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Figure 5.7 Dose response curve for non-carcinogens, suchas heavy metals, have a threshold dose, below which there will be no adverse effect. Carcinogens are assumed to have no safe threshold. The risk can be very small, but it never goes to zero.

Figure 5 7 Dose response curve for non-carcinogens, suchas heavy metals, have a threshold dose, below which there will be no adverse effect. Carcinogens are assumed to have no safe threshold. The risk can be very small, but it never goes to zero.

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the conversation about oncoming rapids and riffles is called politics. The earth is our round river, and we ride on the logs that float down it. The technique of birling is called
the conversation about oncoming rapids and riffles is called politics. The earth is our round river, and we ride on the logs that float down it. The technique of birling is called
Figure 1.3 Metabolism of an industry. Materials that are not converted into products or useful byproducts become wastes or emissions that are contaminated by reactants, impurities in reactants, useless byproducts, solvents, catalysts, and lost products. (Photo credit: freedigitalphotos / supakitmod) Figure 1.3 Metabolism of an industry. Materials that are not converted into products or useful byproducts Figure 1.2 The daily metabolism of a city of 1,000,000 people (Wolman 1965). Not all inputs and outputs are listed. (Photo credit: pixabay)
Figure 1.3 Metabolism of an industry. Materials that are not converted into products or useful byproducts become wastes or emissions that are contaminated by reactants, impurities in reactants, useless byproducts, solvents, catalysts, and lost products. (Photo credit: freedigitalphotos / supakitmod) Figure 1.3 Metabolism of an industry. Materials that are not converted into products or useful byproducts Figure 1.2 The daily metabolism of a city of 1,000,000 people (Wolman 1965). Not all inputs and outputs are listed. (Photo credit: pixabay)
than 1,000,000 people, 63 with more than 5,000,000, and 26 with a population more than 10,000,000
than 1,000,000 people, 63 with more than 5,000,000, and 26 with a population more than 10,000,000
The only way the chemical industry shown in Figure 1.3 could avoid creating waste would be if the raw material inputs were free of impurities, the synthesis chemistry required no excess reactant to drive the reaction and produced no unwanted by-products, and the process operated at ambient conditions of temperature and pressure. In some amount, materials other than product, pure water, and pure air must leave the system. The choice is not whether to discharge waste, but what form and volume shall be discharged and at what pollutant concentrations. Some industries do have a goal of zero discharge of toxic substances.
The only way the chemical industry shown in Figure 1.3 could avoid creating waste would be if the raw material inputs were free of impurities, the synthesis chemistry required no excess reactant to drive the reaction and produced no unwanted by-products, and the process operated at ambient conditions of temperature and pressure. In some amount, materials other than product, pure water, and pure air must leave the system. The choice is not whether to discharge waste, but what form and volume shall be discharged and at what pollutant concentrations. Some industries do have a goal of zero discharge of toxic substances.
Figure 1.4 Understanding the flow of material and energy is fundamental to understanding and solving pollution control problems. All mass and energy entering the system must be accounted for in the system outputs. systems that exist only in our imagination. Figure 1.4 shows an accounting for a simple system.
Figure 1.4 Understanding the flow of material and energy is fundamental to understanding and solving pollution control problems. All mass and energy entering the system must be accounted for in the system outputs. systems that exist only in our imagination. Figure 1.4 shows an accounting for a simple system.
Separating materials is possible whenever they differ in size, density, ionic charge, solubility, or some other property. Each separation stage divides the feed stream into two output streams, one that is enriched with respect to a resource or a pollutant, and one that is depleted. Either of these outputs may need further processing before it is suitable for discharge to the environment, or it becomes a useful product. Figure 1.5 shows a generic separation of a solid from air. There are many ways to do this, as shown in Table 1.1, which is a catalog of methods for separating solids from liquids, solids from gases, gases from gases, liquids from liquids, and solids from solids. gases, liquids from liquids, and solids from solids.
Separating materials is possible whenever they differ in size, density, ionic charge, solubility, or some other property. Each separation stage divides the feed stream into two output streams, one that is enriched with respect to a resource or a pollutant, and one that is depleted. Either of these outputs may need further processing before it is suitable for discharge to the environment, or it becomes a useful product. Figure 1.5 shows a generic separation of a solid from air. There are many ways to do this, as shown in Table 1.1, which is a catalog of methods for separating solids from liquids, solids from gases, gases from gases, liquids from liquids, and solids from solids. gases, liquids from liquids, and solids from solids.
Table 1.1 Separation processes can be combined into hundreds of different pollution control systems and manufacturing processes.
Table 1.1 Separation processes can be combined into hundreds of different pollution control systems and manufacturing processes.
Figure 1.5 A separation process splits a feed stream into two output streams.
Figure 1.5 A separation process splits a feed stream into two output streams.
Figure 1.6 Process are linked, or integrated, as required to produce enriched and depleted outputs that can be released to the environment or transferred to a point of reuse. All of this is done with the understanding that everything entering the system must leave, in one form
Figure 1.6 Process are linked, or integrated, as required to produce enriched and depleted outputs that can be released to the environment or transferred to a point of reuse. All of this is done with the understanding that everything entering the system must leave, in one form
Figure 1.7 A generic integrated system that includes transformations and separations.
Figure 1.7 A generic integrated system that includes transformations and separations.
series, as in Figure 1.6b.
series, as in Figure 1.6b.
Figure 1.8 The arrangement of processes is identical to Figure 1.7, but naming the processes reveals a commonly used scheme for treating municipal wastewater. The three transformations are all done biologically. The boxes all represent physical separations of solids and water. Separations of gases from liquid are shown with arrows.
Figure 1.8 The arrangement of processes is identical to Figure 1.7, but naming the processes reveals a commonly used scheme for treating municipal wastewater. The three transformations are all done biologically. The boxes all represent physical separations of solids and water. Separations of gases from liquid are shown with arrows.
Figure 2.1 A preliminary schematic for the screen-printing operation. More details will be needed on the solvent composition, point of use, and point of ventilation or emission. Quantities will be revised.
Figure 2.1 A preliminary schematic for the screen-printing operation. More details will be needed on the solvent composition, point of use, and point of ventilation or emission. Quantities will be revised.
Figure 2.2 Design proceeds in stages, from preliminary concepts to final design. The early stages offer the greatest opportunity for innovation.
Figure 2.2 Design proceeds in stages, from preliminary concepts to final design. The early stages offer the greatest opportunity for innovation.
analysis select the alternatives that need to be studied in more detail.
analysis select the alternatives that need to be studied in more detail.
Figure 2.3 Industrial reductions in 17 targeted toxic chemicals under the voluntary 33/50 program (USEPA 1999).
Figure 2.3 Industrial reductions in 17 targeted toxic chemicals under the voluntary 33/50 program (USEPA 1999).
Figure 2.4 Cradle-to-grave analysis of a manufactured product. Energy is consumed and waste is generated in each phase of the life cycle. to dismantle at the end of their useful life so parts and materials can be recycled. Pollution prevention will
Figure 2.4 Cradle-to-grave analysis of a manufactured product. Energy is consumed and waste is generated in each phase of the life cycle. to dismantle at the end of their useful life so parts and materials can be recycled. Pollution prevention will
Figure 2.6 An ideal reaction produces no waste. Real reactions yield a mixture of product and other materials. A separation process is needed to support the chemical transformation. a ‘clear or ‘greer’ reaction. This is the goal of Green Chemistry.
Figure 2.6 An ideal reaction produces no waste. Real reactions yield a mixture of product and other materials. A separation process is needed to support the chemical transformation. a ‘clear or ‘greer’ reaction. This is the goal of Green Chemistry.
Figure 2.5 Waste minimization methods. manufacturing process and making changes may not be easy even if good ideas seem plentiful.
Figure 2.5 Waste minimization methods. manufacturing process and making changes may not be easy even if good ideas seem plentiful.
Figure 2.7 Economy-of-scale cost function used for naking preliminary cost estimates. This curve is for a This also means that halving the design capacity will reduce the cost by 38%. f the cost exponent is less than 1.0 there is an economy of scale. This means that doubling the capacity
Figure 2.7 Economy-of-scale cost function used for naking preliminary cost estimates. This curve is for a This also means that halving the design capacity will reduce the cost by 38%. f the cost exponent is less than 1.0 there is an economy of scale. This means that doubling the capacity
Figure 2.8 Alternate designs may be compared on the basis of cost, either the first cost of construction or the lifetime cost, but they differ in many characteristics and effectiveness should be considered as well. Figure 2.8 Alternate designs may be compared on the basis of cost, either the first cost of construction
Figure 2.8 Alternate designs may be compared on the basis of cost, either the first cost of construction or the lifetime cost, but they differ in many characteristics and effectiveness should be considered as well. Figure 2.8 Alternate designs may be compared on the basis of cost, either the first cost of construction
but lacks a volatile form, so it moves between the land and water. Carbon, nitrogen, oxygen, hydrogen, sulfur, and water can exist as soluble and as volatile forms, and
but lacks a volatile form, so it moves between the land and water. Carbon, nitrogen, oxygen, hydrogen, sulfur, and water can exist as soluble and as volatile forms, and
Figure 3.1 The water cycle, or hydrologic cycle. is a central problem in environmental protection. Figure 3.2 shows that 99% of all water on earth is not directly available for human use. About 97% of the total is saline (oceans). Almost 68.7% of the fresh water on earth exists as ice in glaciers and icecaps and 30.1% is groundwater. That leaves 0.9% of the total as surface water. Of this small fraction, only 2% is in rivers, 87% is in lakes, and 11% is in swamps. Almost one-quarter of the world’s population, 1.7 billion people, lives in regions where groundwater is being used up faster than it can be replenished (Gleeson 2012, Pearce 2006).
Figure 3.1 The water cycle, or hydrologic cycle. is a central problem in environmental protection. Figure 3.2 shows that 99% of all water on earth is not directly available for human use. About 97% of the total is saline (oceans). Almost 68.7% of the fresh water on earth exists as ice in glaciers and icecaps and 30.1% is groundwater. That leaves 0.9% of the total as surface water. Of this small fraction, only 2% is in rivers, 87% is in lakes, and 11% is in swamps. Almost one-quarter of the world’s population, 1.7 billion people, lives in regions where groundwater is being used up faster than it can be replenished (Gleeson 2012, Pearce 2006).
Figure 3.2 Distribution of the earth’s water (adapted from U.S Geological Society).
Figure 3.2 Distribution of the earth’s water (adapted from U.S Geological Society).
Figure 3.3 Water use in the manufacturing process. Wastewater consists of process waste, water used for cleanup and for air pollution control, drainage from floors, as well as unpolluted process and cooling water and stormwater. This diagram, for simplicity, shows all wastewater going into a common drain. Better practice is to segregate (i.e. collect separately) different kinds of wastewater. For example, do not mix unpolluted water with polluted water.
Figure 3.3 Water use in the manufacturing process. Wastewater consists of process waste, water used for cleanup and for air pollution control, drainage from floors, as well as unpolluted process and cooling water and stormwater. This diagram, for simplicity, shows all wastewater going into a common drain. Better practice is to segregate (i.e. collect separately) different kinds of wastewater. For example, do not mix unpolluted water with polluted water.
Figure 3.4 The Industrial Water Cycle. Industries run on water and energy as much as on raw materials used in the actual manufacturing. Water for the formulation and refinement of the product is supplied from plant utilities, which also supplies boilers and cooling towers. Wastewater streams include blowdown from boilers and cooling towers, scrubbers, and waste from manufacturing, including washwater. Water treatment and wastewater treatment produce sludge. There may also be solid wastes (not shown) from manufacturing. Waste treatment may be done off-site at a municipal treatment plant, but on-site treatment will offer more opportunities to recycle water. Figure 3.4 The Industrial Water Cycle. Industries run on water and energy as much as on raw materials used in the actual
Figure 3.4 The Industrial Water Cycle. Industries run on water and energy as much as on raw materials used in the actual manufacturing. Water for the formulation and refinement of the product is supplied from plant utilities, which also supplies boilers and cooling towers. Wastewater streams include blowdown from boilers and cooling towers, scrubbers, and waste from manufacturing, including washwater. Water treatment and wastewater treatment produce sludge. There may also be solid wastes (not shown) from manufacturing. Waste treatment may be done off-site at a municipal treatment plant, but on-site treatment will offer more opportunities to recycle water. Figure 3.4 The Industrial Water Cycle. Industries run on water and energy as much as on raw materials used in the actual
Figure 3.5 Cooling water loop showing make-up water being added and blowdown being removed. (Photo credit: freedigitalphotos, supakitmod)
Figure 3.5 Cooling water loop showing make-up water being added and blowdown being removed. (Photo credit: freedigitalphotos, supakitmod)
Figure 3.6 The natural carbon cycle is linked to the oxygen cycle. (Quantities are from NOAH Research 1996. Photo credits: freedigitalphotos ) One of the important reactions in the carbon cycle is a classical cause of water pollution. Lakes and rivers absorb oxygen from the atmosphere while microorganisms simultaneously consume dissolved oxygen and organic carbon from the water. When food (carbon) is plentiful, oxygen is consumed faster than it can be replaced from the atmosphere. This reduces the dissolved oxygen (DO) and can endanger fish and other desirable aquatic organisms. and organic carbon from the water. When food (carbon) is plentiful, oxygen is consumed faster than it
Figure 3.6 The natural carbon cycle is linked to the oxygen cycle. (Quantities are from NOAH Research 1996. Photo credits: freedigitalphotos ) One of the important reactions in the carbon cycle is a classical cause of water pollution. Lakes and rivers absorb oxygen from the atmosphere while microorganisms simultaneously consume dissolved oxygen and organic carbon from the water. When food (carbon) is plentiful, oxygen is consumed faster than it can be replaced from the atmosphere. This reduces the dissolved oxygen (DO) and can endanger fish and other desirable aquatic organisms. and organic carbon from the water. When food (carbon) is plentiful, oxygen is consumed faster than it
Figure 3.7 Global annual average temperature (as measured over land and oceans). The curve shows the historic levels of atmospheric carbon dioxide (CO,), measured in ppmv. The horizontal line is the average temperature for the period 1901-2000. The bars indicate temperature deviations above and below the average temperature. The year-to-year fluctuations in temperature are due to natural processes, such as the effects of El Nifos, La Nifas, and the eruption of large volcanoes. (Karl et al. 2011) Burning coal, petroleum and natural gas emits roughly 7.5 billion metric tons of carbon per year. The
Figure 3.7 Global annual average temperature (as measured over land and oceans). The curve shows the historic levels of atmospheric carbon dioxide (CO,), measured in ppmv. The horizontal line is the average temperature for the period 1901-2000. The bars indicate temperature deviations above and below the average temperature. The year-to-year fluctuations in temperature are due to natural processes, such as the effects of El Nifos, La Nifas, and the eruption of large volcanoes. (Karl et al. 2011) Burning coal, petroleum and natural gas emits roughly 7.5 billion metric tons of carbon per year. The
Table 3.1 Elements essential to life.
Table 3.1 Elements essential to life.
Figure 3.8 The Nitrogen Cycle. Nitrogen in the atmosphere can be fixed by industrial fertilizer production or by nitrogen-fixing plants (legumes). Organic N, mainly proteins, decomposes to yield ammonia, which is converted in the body to urea for excretion. In the presence of oxygen, nitrifying bacteria will convert ammonia to nitrite and to nitrate (NO,) and then nitrate to nitrate (NO,). Ammonia, nitrite and nitrate can be taken up by plants and, hence converted back to organic nitrogen. Nitrate can be converted, in a biological process to nitrogen gas. Figure 3.8 The Nitrogen Cycle. Nitrogen in the atmosphere can be fixed by industrial fertilizer
Figure 3.8 The Nitrogen Cycle. Nitrogen in the atmosphere can be fixed by industrial fertilizer production or by nitrogen-fixing plants (legumes). Organic N, mainly proteins, decomposes to yield ammonia, which is converted in the body to urea for excretion. In the presence of oxygen, nitrifying bacteria will convert ammonia to nitrite and to nitrate (NO,) and then nitrate to nitrate (NO,). Ammonia, nitrite and nitrate can be taken up by plants and, hence converted back to organic nitrogen. Nitrate can be converted, in a biological process to nitrogen gas. Figure 3.8 The Nitrogen Cycle. Nitrogen in the atmosphere can be fixed by industrial fertilizer
Figure 3.9 The natural cycle of Phosphorus (P) in water. Organic and inorganic P can exist as particulate or soluble materials. Transport of P to land by sea birds and by human harvesting of fish or aquatic plants is not shown. Atmospheric transport of sea spray is a minor mechanism. (Photo credit: pixabay)
Figure 3.9 The natural cycle of Phosphorus (P) in water. Organic and inorganic P can exist as particulate or soluble materials. Transport of P to land by sea birds and by human harvesting of fish or aquatic plants is not shown. Atmospheric transport of sea spray is a minor mechanism. (Photo credit: pixabay)
Figure 3.11 The Sulfur Cycle. (Photo credit: pixabay; freedigitalphotos, worradmu & prozac’)
Figure 3.11 The Sulfur Cycle. (Photo credit: pixabay; freedigitalphotos, worradmu & prozac’)
Table 4.1 Scale of toxicity for three routes of administration. (Hodge and Sterner 1956)
Table 4.1 Scale of toxicity for three routes of administration. (Hodge and Sterner 1956)
Figure 4.1 Acute toxic bioassay data for bluegill exposed to copper Figure 4.1 shows that the survival of bluegills exposed to copper (Cu) decreases as exposure time increases. At 0.6 mg/L, the 96-hr LC,, 85% of organisms survive for 48 hours, 50% survive for 96 hours, and just over 10% survive for 144 hours. In this case the relation between exposure time and LC,, is almost linear and we find LC, -144-hr = 0.40 mg/L, LC,,-96-hr = 0.60 mg/L, and LC, -48-hr = 0.76 mg/L Cu. linear and we find LC, -144-hr = 0.40 mg/L, LC, -96-hr = 0.60 mg/L, and LC,,-48-hr = 0.76 mg/L Cu
Figure 4.1 Acute toxic bioassay data for bluegill exposed to copper Figure 4.1 shows that the survival of bluegills exposed to copper (Cu) decreases as exposure time increases. At 0.6 mg/L, the 96-hr LC,, 85% of organisms survive for 48 hours, 50% survive for 96 hours, and just over 10% survive for 144 hours. In this case the relation between exposure time and LC,, is almost linear and we find LC, -144-hr = 0.40 mg/L, LC,,-96-hr = 0.60 mg/L, and LC, -48-hr = 0.76 mg/L Cu. linear and we find LC, -144-hr = 0.40 mg/L, LC, -96-hr = 0.60 mg/L, and LC,,-48-hr = 0.76 mg/L Cu
Discover the truth at www.deloitte.ca/careers
Discover the truth at www.deloitte.ca/careers
Figure 4.2 Typical effluent bioassay test showing the NOEL, LOEL, and EC... NOEL = No Observed Effect Level, the highest level at which the response is not significantly different statistically from controls. NOEL is normally only used in chronic toxicity tests. LOEL = Lowest Observed Effect Level, is the lowest dose at which the response can be statistically distinguished from the control group. The NOEL is the next lowest dose below the LOEL. The LOEL and NOEL may correspond to an effect that is observable but is not adverse and of no practical importance. Figure 4.2 Typical effluent bioassay test showing the NOEL, LOEL, and A toxic response in the screening test may lead to a definitive test to estimate the concentration or percentage of effluent at which a certain percentage or significant fraction of organisms exhibit a certain response. Organisms are exposed to a predetermined array of test solutions containing various proportions of effluent.
Figure 4.2 Typical effluent bioassay test showing the NOEL, LOEL, and EC... NOEL = No Observed Effect Level, the highest level at which the response is not significantly different statistically from controls. NOEL is normally only used in chronic toxicity tests. LOEL = Lowest Observed Effect Level, is the lowest dose at which the response can be statistically distinguished from the control group. The NOEL is the next lowest dose below the LOEL. The LOEL and NOEL may correspond to an effect that is observable but is not adverse and of no practical importance. Figure 4.2 Typical effluent bioassay test showing the NOEL, LOEL, and A toxic response in the screening test may lead to a definitive test to estimate the concentration or percentage of effluent at which a certain percentage or significant fraction of organisms exhibit a certain response. Organisms are exposed to a predetermined array of test solutions containing various proportions of effluent.
Figure 4.3 Species sensitivity to copper. acute values for at least eight taxonomic families of aquatic organisms, as shown in Table 4.4.
Figure 4.3 Species sensitivity to copper. acute values for at least eight taxonomic families of aquatic organisms, as shown in Table 4.4.
Site-Specific Water Quality Criteria The GMAVs are plotted against the percentile rank in Figure 4.4 and a straight line is drawn to facilitate interpolation to find the FAV at the lower fifth percentile point. calcium and magnesium in the water) is known to moderate the toxicity of some metals.
Site-Specific Water Quality Criteria The GMAVs are plotted against the percentile rank in Figure 4.4 and a straight line is drawn to facilitate interpolation to find the FAV at the lower fifth percentile point. calcium and magnesium in the water) is known to moderate the toxicity of some metals.
without trout. Using this approach requires stream surveys to identify the indigenous aquatic organisms.
without trout. Using this approach requires stream surveys to identify the indigenous aquatic organisms.
Table 4.6 Parameters for calculating the acute and chronic toxicity for seven metals as a function of water hardness. (Federal Register, vol 56, no. 223, p. 58444, 1991) Table 4.6 gives the values of m and b for seven heavy metals.
Table 4.6 Parameters for calculating the acute and chronic toxicity for seven metals as a function of water hardness. (Federal Register, vol 56, no. 223, p. 58444, 1991) Table 4.6 gives the values of m and b for seven heavy metals.
Figure 4.5 The toxicity of heavy metals decreases (the LC,, increases) as water hardness increases. Data for four fish species and Daphnidae sp show a wide range tolerance to copper. increases. Similar results are seen for cadmium, chromium III, copper, lead, nickel, silver, and zinc.
Figure 4.5 The toxicity of heavy metals decreases (the LC,, increases) as water hardness increases. Data for four fish species and Daphnidae sp show a wide range tolerance to copper. increases. Similar results are seen for cadmium, chromium III, copper, lead, nickel, silver, and zinc.
Figure 4.6 Percent Un-ionized ammonia as a function of water pH and temperature. The approximate concentrations of the two ammonia species are
Figure 4.6 Percent Un-ionized ammonia as a function of water pH and temperature. The approximate concentrations of the two ammonia species are
Chronic Continuous Concentration (CCC) - Early Life Stages Present (mg/L as N) Chronic Continuous Concentration (CCC) - Early Life Stages Absent (mg/L as N)
Chronic Continuous Concentration (CCC) - Early Life Stages Present (mg/L as N) Chronic Continuous Concentration (CCC) - Early Life Stages Absent (mg/L as N)
Table 4.7 Chronic Water Criteria for Total Ammonia (mg/L as N).
Table 4.7 Chronic Water Criteria for Total Ammonia (mg/L as N).
model and reality. Risk assessment is a simplified model of the real world that relies on many assumptions and subjective judgments. The models are useful, but they are certain to be wrong with respect to some parts of the real world. Conclusions are vulnerable to error caused by gaps in the data that lead to gaps between the model and reality.
model and reality. Risk assessment is a simplified model of the real world that relies on many assumptions and subjective judgments. The models are useful, but they are certain to be wrong with respect to some parts of the real world. Conclusions are vulnerable to error caused by gaps in the data that lead to gaps between the model and reality.
Figure 5.1 A risk profile matrix of a semi-quantitative risk assessment. The factors are the likelihood of an event occurring and the severity of the consequences if it does occur. The scales divide these two factors into five categories (more or less could be used) and they are arbitrarily given weights of 1 through 5. The numbers in the cells are the products of the marginal weights. Figure 5.1 A risk profile matrix of a semi-quantitative risk assessment. The factors are the likelihood of an event if they occur.
Figure 5.1 A risk profile matrix of a semi-quantitative risk assessment. The factors are the likelihood of an event occurring and the severity of the consequences if it does occur. The scales divide these two factors into five categories (more or less could be used) and they are arbitrarily given weights of 1 through 5. The numbers in the cells are the products of the marginal weights. Figure 5.1 A risk profile matrix of a semi-quantitative risk assessment. The factors are the likelihood of an event if they occur.
Figure 5.2 Hazardous material identification symbol showing the types of active hazard that could be created by an accidental release flammability, and strong chemical reactions, including possible explosions. A hazard is a situation that poses a threat to life, health, property, or the environment. Most hazards pose only a theoretical risk of harm. A toxic chemical becomes an active hazard (danger, harm) when toxicity and exposure are combined. Trucks and rail cars that haul hazardous materials are clearly marked with the familiar sign shown in Figure 5.2 so emergency crews will know exactly what hazard they face in case of an accident. This sign shows that materials can be hazardous in many different ways, by toxicity, flammability, and strong chemical reactions, including possible explosions.
Figure 5.2 Hazardous material identification symbol showing the types of active hazard that could be created by an accidental release flammability, and strong chemical reactions, including possible explosions. A hazard is a situation that poses a threat to life, health, property, or the environment. Most hazards pose only a theoretical risk of harm. A toxic chemical becomes an active hazard (danger, harm) when toxicity and exposure are combined. Trucks and rail cars that haul hazardous materials are clearly marked with the familiar sign shown in Figure 5.2 so emergency crews will know exactly what hazard they face in case of an accident. This sign shows that materials can be hazardous in many different ways, by toxicity, flammability, and strong chemical reactions, including possible explosions.
Figure 5.3 Annual risk of death (per person per year) for some “risky” activities.
Figure 5.3 Annual risk of death (per person per year) for some “risky” activities.
Risk = (Probability of critical event)(Probability of exposure to event)
Risk = (Probability of critical event)(Probability of exposure to event)
Figure 5.4 Illustration of risk as the combination of exposure and probability of Our discussion will be about toxic chemicals in air and water. Good engineering can reduce the hazard by limiting either the dose or the exposure, or both. For example:
Figure 5.4 Illustration of risk as the combination of exposure and probability of Our discussion will be about toxic chemicals in air and water. Good engineering can reduce the hazard by limiting either the dose or the exposure, or both. For example:
Figure 5.6 Epidemiological studies and laboratory studies provide different kinds of information. Both are needed and both are valuable. When clear epidemiological information does not exist data from laboratory studies are used to extrapolate risks in the real world. Figure 5.6 Epidemiological studies and laboratory studies provide different residents in cities with highly polluted air. Good epidemiological studies top all other information, but they do not exist for most chemicals. They evaluate the health of real people in the real world. The most definitive studies are of clearly identified groups of industrial workers, or very large groups of exposed people, such as smokers and long-term residents in cities with highly polluted air. Good epidemiological studies top all other information, but they do not exist for most chemicals. They The regulator's dilemma, shown in Figure 5.5, is deciding whether a chemical or substance should be banned or regulated. There are two correct decisions and two that are wrong. The worst mistake is failure to ban or regulate a truly dangerous substance. We also want to not ban substances that are harmless because this mistake will waste time and money that could be better used on real problems.
Figure 5.6 Epidemiological studies and laboratory studies provide different kinds of information. Both are needed and both are valuable. When clear epidemiological information does not exist data from laboratory studies are used to extrapolate risks in the real world. Figure 5.6 Epidemiological studies and laboratory studies provide different residents in cities with highly polluted air. Good epidemiological studies top all other information, but they do not exist for most chemicals. They evaluate the health of real people in the real world. The most definitive studies are of clearly identified groups of industrial workers, or very large groups of exposed people, such as smokers and long-term residents in cities with highly polluted air. Good epidemiological studies top all other information, but they do not exist for most chemicals. They The regulator's dilemma, shown in Figure 5.5, is deciding whether a chemical or substance should be banned or regulated. There are two correct decisions and two that are wrong. The worst mistake is failure to ban or regulate a truly dangerous substance. We also want to not ban substances that are harmless because this mistake will waste time and money that could be better used on real problems.
cost of a useful level of knowledge is millions of dollars per chemical.
cost of a useful level of knowledge is millions of dollars per chemical.
Figure 5.8 Dose response data for rats exposed to arsenite.
Figure 5.8 Dose response data for rats exposed to arsenite.
Figure 5.8 shows dose-response data for animals exposed to the carcinogen arsenic (arsenite). The arsenite dose, measured in mg arsenite/kg body weight (ppm), is constant over the term of the experiment. The four data points are in the upper right hand corner of the plot. The straight line is the extrapolation of risk. Note that extrapolation over more than a 100,000-fold range is necessary to predict the dose that gives an added risk of 10° orl0°.
Figure 5.8 shows dose-response data for animals exposed to the carcinogen arsenic (arsenite). The arsenite dose, measured in mg arsenite/kg body weight (ppm), is constant over the term of the experiment. The four data points are in the upper right hand corner of the plot. The straight line is the extrapolation of risk. Note that extrapolation over more than a 100,000-fold range is necessary to predict the dose that gives an added risk of 10° orl0°.
Incremental individual lifetime cancer risk = CDI x SF The model for incremental individual risk to an exposed individual is
Incremental individual lifetime cancer risk = CDI x SF The model for incremental individual risk to an exposed individual is
Table 5.2 Toxicity Data for Selected Potential Carcinogens Table 5.1 EPA Recommended standard values for Daily Intake Calculations
Table 5.2 Toxicity Data for Selected Potential Carcinogens Table 5.1 EPA Recommended standard values for Daily Intake Calculations
for a few important chemicals. Tables 5.1 gives the default values for body weight and consumption that are widely used for risk calculations. Fish consumption is included because bioaccumulation of carcinogens in the edible tissue may create a significant cancer risk. Table 5.2 lists some cancer potency factors and other characteristics for a few important chemicals.
for a few important chemicals. Tables 5.1 gives the default values for body weight and consumption that are widely used for risk calculations. Fish consumption is included because bioaccumulation of carcinogens in the edible tissue may create a significant cancer risk. Table 5.2 lists some cancer potency factors and other characteristics for a few important chemicals.
relative source contribution (RCS). This applies to chemicals that have a threshold toxicity. Risk-based Standards for Drinking Wate 1 Relative Source Contribution
relative source contribution (RCS). This applies to chemicals that have a threshold toxicity. Risk-based Standards for Drinking Wate 1 Relative Source Contribution
Table 5.3 A sample of Relative Source Contribution factors for drinking water (USEPA 2000) The USEPA has used values of 0.2 to 0.8 (20% to 80%) of the total acceptable exposure for drinking water, with 0.2 (20%) being the default value in the absence of good data. The total exposure should not exceed the reference dose (RfD). This approach has been used to derive public health goals (PHGs) for 69 chemicals. Some of the values used in the derivation of public health goals are in Table 5.3. 59 chemicals. Some of the values used in the derivation of public health goals are in Table 5.3. The Maximum Contaminant Level Goal (MCLG) is a non-enforceable health-based goal. For known carcinogens, or cancer-causing agents, the goal is set at zero, assuming that any level of consumption presents a cancer risk. For non-carcinogens the MCLG level is based on the assumption that a person could consume two liters of drinking water containing the maximum level of the contaminant daily for 70 years without experiencing any known health effects The Maximum Contaminant Level Goal (MCLG) is a non-enforceable health-based goal. For known
Table 5.3 A sample of Relative Source Contribution factors for drinking water (USEPA 2000) The USEPA has used values of 0.2 to 0.8 (20% to 80%) of the total acceptable exposure for drinking water, with 0.2 (20%) being the default value in the absence of good data. The total exposure should not exceed the reference dose (RfD). This approach has been used to derive public health goals (PHGs) for 69 chemicals. Some of the values used in the derivation of public health goals are in Table 5.3. 59 chemicals. Some of the values used in the derivation of public health goals are in Table 5.3. The Maximum Contaminant Level Goal (MCLG) is a non-enforceable health-based goal. For known carcinogens, or cancer-causing agents, the goal is set at zero, assuming that any level of consumption presents a cancer risk. For non-carcinogens the MCLG level is based on the assumption that a person could consume two liters of drinking water containing the maximum level of the contaminant daily for 70 years without experiencing any known health effects The Maximum Contaminant Level Goal (MCLG) is a non-enforceable health-based goal. For known
Table 5.4. Maximum Contaminant Level (MCL) for selected chemicals taken from the U.S. Recommended Drinking Water Criteria (USEPA 2011). Table 5.4 lists MCL values for a few chemicals. Appendix 1 is a more complete list. where FI = fish intake (mg/day)
Table 5.4. Maximum Contaminant Level (MCL) for selected chemicals taken from the U.S. Recommended Drinking Water Criteria (USEPA 2011). Table 5.4 lists MCL values for a few chemicals. Appendix 1 is a more complete list. where FI = fish intake (mg/day)
If the chemical is a Class C carcinogen (suggestive evidence of carcinogenic potential), divide by uncertainty facto UF = 10.
If the chemical is a Class C carcinogen (suggestive evidence of carcinogenic potential), divide by uncertainty facto UF = 10.
Notes: Dry weight basis means that 100 kg of dry sludge solids will contain from 4 to 8 kg of total nitrogen. 100 kg of dry sludge solids will contain, on average, (100 kg)(10 mg/kg) = 1000 mg Arsenic. [he average composition of municipal sewage sludge in the U.S. is given in Table 5.5.
Notes: Dry weight basis means that 100 kg of dry sludge solids will contain from 4 to 8 kg of total nitrogen. 100 kg of dry sludge solids will contain, on average, (100 kg)(10 mg/kg) = 1000 mg Arsenic. [he average composition of municipal sewage sludge in the U.S. is given in Table 5.5.
Figure 5.9 Pathways for risk assessment of the beneficial use of biosolids under the Part 503 regulations (USEPA 1992). plants (phytotoxicity).
Figure 5.9 Pathways for risk assessment of the beneficial use of biosolids under the Part 503 regulations (USEPA 1992). plants (phytotoxicity).
Table 5.7 The Part 503 limitations on heavy metals set in the Part 503 Rule for land disposal of municipal sewage sludge (USEPA 1992).
Table 5.7 The Part 503 limitations on heavy metals set in the Part 503 Rule for land disposal of municipal sewage sludge (USEPA 1992).
The AWSAR for the sludge is the lowest of the individual AWSARs calculated for the 10 regulated metals. The lowest AWSAR is copper (Cu). The limit is 20 tonne/ha-yr (410 Ib/ft?-yr). Table 5.9 Annual whole sludge application rate (AWSAR) calculations 5.10.4 The Risk Assessment Assumptions
The AWSAR for the sludge is the lowest of the individual AWSARs calculated for the 10 regulated metals. The lowest AWSAR is copper (Cu). The limit is 20 tonne/ha-yr (410 Ib/ft?-yr). Table 5.9 Annual whole sludge application rate (AWSAR) calculations 5.10.4 The Risk Assessment Assumptions
routes, but we dare not rely only on these analogies to suggest that a substance is safe.
routes, but we dare not rely only on these analogies to suggest that a substance is safe.
Figure 6.1 A colorized version of the original map by John Snow showing the clusters of cholera cases (red dots) in the London epidemic of 1854 and the locations of wells in the neighborhood. The Broad Street well is the blue dot at the center of the cluster. This well was the source of the cholera infection. handle of the pump was removed on the following day.”
Figure 6.1 A colorized version of the original map by John Snow showing the clusters of cholera cases (red dots) in the London epidemic of 1854 and the locations of wells in the neighborhood. The Broad Street well is the blue dot at the center of the cluster. This well was the source of the cholera infection. handle of the pump was removed on the following day.”
water-borne disease.
water-borne disease.
Table 6.2 Probability of infection for some pathogenic microorganisms. (USEPA 2012). a single organism and the exposure that is predicted to cause a 1% risk of infection.
Table 6.2 Probability of infection for some pathogenic microorganisms. (USEPA 2012). a single organism and the exposure that is predicted to cause a 1% risk of infection.
Figure 6.2 Probability of infection by Rotavirus as predicted by the Beta- Pr a i | Figure 6.2 was generated using this model over a wide range of doses. he probability of infection can be estimated as the product of the exposure from drinking water and 1e probability that exposure to one organism would result in infection. Not all infected individuals ill develop clinical illness; asymptomatic infection is common for most pathogens. The percentage of ifected persons that will develop clinical illness depends on the pathogen, but also on other factors, ich as the immune status of the host.
Figure 6.2 Probability of infection by Rotavirus as predicted by the Beta- Pr a i | Figure 6.2 was generated using this model over a wide range of doses. he probability of infection can be estimated as the product of the exposure from drinking water and 1e probability that exposure to one organism would result in infection. Not all infected individuals ill develop clinical illness; asymptomatic infection is common for most pathogens. The percentage of ifected persons that will develop clinical illness depends on the pathogen, but also on other factors, ich as the immune status of the host.
The basic principle of the DALY is to weight each health effect for its severity from 0 (normal good health) to 1 (death). This weight is multiplied by the duration of the effect and by the number of people affected by a particular outcome. It is then possible to sum the effects of all different outcomes due to a particular agent. The duration is the time during which disease is apparent. When the outcome is death, the “duration” is the remaining life expectancy. the “duration” is the remaining life expectancy.
The basic principle of the DALY is to weight each health effect for its severity from 0 (normal good health) to 1 (death). This weight is multiplied by the duration of the effect and by the number of people affected by a particular outcome. It is then possible to sum the effects of all different outcomes due to a particular agent. The duration is the time during which disease is apparent. When the outcome is death, the “duration” is the remaining life expectancy. the “duration” is the remaining life expectancy.
Data from high-income regions. In low-income regions, severity is typically higher, but drinking-water transmission is unlikely to dominate. This reflects the acute end-points (e.g., diarrhoeal illness) and also mortality and the effects of more serious end-points. Disease burden per case varies widely. For example, the disease burden per 1000 cases of rotavirus diarrhea is 480 DALYs in low-income regions, where child mortality is frequent, but only 14 DALYs per 1000 cases in high-income regions where hospital facilities are accessible to the great majority of the population. Table 6.3 Method for linking tolerable disease burden and source water quality for reference pathogens: example calculation for an acceptable disease burden of 1 x 10°DALYs per year. No accounting is made for effects on immune-compromised persons (e.g., cryptosporidiosis in HIV/AIDS patients), which is significant in some countries. only 14 DALYs per 1000 cases in high-income regions where hospital facilities are accessible to the great
Data from high-income regions. In low-income regions, severity is typically higher, but drinking-water transmission is unlikely to dominate. This reflects the acute end-points (e.g., diarrhoeal illness) and also mortality and the effects of more serious end-points. Disease burden per case varies widely. For example, the disease burden per 1000 cases of rotavirus diarrhea is 480 DALYs in low-income regions, where child mortality is frequent, but only 14 DALYs per 1000 cases in high-income regions where hospital facilities are accessible to the great majority of the population. Table 6.3 Method for linking tolerable disease burden and source water quality for reference pathogens: example calculation for an acceptable disease burden of 1 x 10°DALYs per year. No accounting is made for effects on immune-compromised persons (e.g., cryptosporidiosis in HIV/AIDS patients), which is significant in some countries. only 14 DALYs per 1000 cases in high-income regions where hospital facilities are accessible to the great
Figure 6.3 The colored bands show the Ct required for 99% kill or inactivation of bacteria, virus and protozoans. Cryptosporidium is not inactivated at these conditions. information. Higher pH requires a higher Ct ; lower temperature requires a higher Ct. For a contact basin of fixed volume (fixed contact time) the most practical control is variation of th concentration or intensity. The job can be done with intense exposure (high concentration of chlorin or intense UV radiation) and a short contact time, or with low exposure for a longer time. Figure 6.: shows the Ct requirements for 99% kill of bacteria, virus and protozoa. Table 6.4 provides more detailec information. Higher pH requires a higher Ct ; lower temperature requires a higher Ct.
Figure 6.3 The colored bands show the Ct required for 99% kill or inactivation of bacteria, virus and protozoans. Cryptosporidium is not inactivated at these conditions. information. Higher pH requires a higher Ct ; lower temperature requires a higher Ct. For a contact basin of fixed volume (fixed contact time) the most practical control is variation of th concentration or intensity. The job can be done with intense exposure (high concentration of chlorin or intense UV radiation) and a short contact time, or with low exposure for a longer time. Figure 6.: shows the Ct requirements for 99% kill of bacteria, virus and protozoa. Table 6.4 provides more detailec information. Higher pH requires a higher Ct ; lower temperature requires a higher Ct.
Table 6.4 Reduction of bacteria, viruses and protozoa achieved by chlorination and membrane processes. Ct is the product of disinfectant concentration (mg/L) and contact time (min). Inactivation is directly proportional to the Ct values. Ct and UV radiation levels apply to microorganisms in suspension, not embedded in particles. Table 6.4 Reduction of bacteria, viruses and protozoa achieved by chlorination and membrane processes. Ct is the product of
Table 6.4 Reduction of bacteria, viruses and protozoa achieved by chlorination and membrane processes. Ct is the product of disinfectant concentration (mg/L) and contact time (min). Inactivation is directly proportional to the Ct values. Ct and UV radiation levels apply to microorganisms in suspension, not embedded in particles. Table 6.4 Reduction of bacteria, viruses and protozoa achieved by chlorination and membrane processes. Ct is the product of
Figure 6.4 Animal husbandry can contribute pathogens by direct contamination by animals in the water body as well as runoff from pens, storage ponds and cropland. The on-site storage of manure, the runoff collection pond, and a green buffer zone between the stream and the source area help to reduce pollution. Figure 6.4 Animal husbandry can contribute pathogens by direct contamination by animals in the water body as well as runoff
Figure 6.4 Animal husbandry can contribute pathogens by direct contamination by animals in the water body as well as runoff from pens, storage ponds and cropland. The on-site storage of manure, the runoff collection pond, and a green buffer zone between the stream and the source area help to reduce pollution. Figure 6.4 Animal husbandry can contribute pathogens by direct contamination by animals in the water body as well as runoff
Figure 6.5 Distribution of the volume of water ingested by swimmers during 45 minutes of activity. 80% of children ingested more than 10 mL of water, 60% ingested more than 20 mL, and 20 % ingested more than 50 mL. (Source USEPA 2010)
Figure 6.5 Distribution of the volume of water ingested by swimmers during 45 minutes of activity. 80% of children ingested more than 10 mL of water, 60% ingested more than 20 mL, and 20 % ingested more than 50 mL. (Source USEPA 2010)
protecting the soil and the stream bank. The mass of manure applied to the land and the net runoff during the storm are known more precisely than the other values. The density of organisms and species depends on the kind of animals and their pathogen shedding abundance. The fraction of organisms mobilized depends on the rainfall intensity, rainfall duration, antecedent soil moisture, how the manure was incorporated into the soil, and vegetation protecting the soil and the stream bank.
protecting the soil and the stream bank. The mass of manure applied to the land and the net runoff during the storm are known more precisely than the other values. The density of organisms and species depends on the kind of animals and their pathogen shedding abundance. The fraction of organisms mobilized depends on the rainfall intensity, rainfall duration, antecedent soil moisture, how the manure was incorporated into the soil, and vegetation protecting the soil and the stream bank.
Figure 6.6 Risks estimates from a Monte Carlo simulation for the five major pathogens in recreational water contamination by pig, cattle, and chicken manure. The horizontal line is the risk of infection for the current recreational water quality criteria. The bars in the boxes indicate the median values, the boxes bound the middle 50% of the estimated values, and the bars on the extended lines bound 99% of the estimated values. (USEPA 2010) If these odds are unacceptable then better management methods are needed for handling animal manure
Figure 6.6 Risks estimates from a Monte Carlo simulation for the five major pathogens in recreational water contamination by pig, cattle, and chicken manure. The horizontal line is the risk of infection for the current recreational water quality criteria. The bars in the boxes indicate the median values, the boxes bound the middle 50% of the estimated values, and the bars on the extended lines bound 99% of the estimated values. (USEPA 2010) If these odds are unacceptable then better management methods are needed for handling animal manure
supply can persist. Table 6.5 summarizes some of these concerns. Table 6.5 Waterborne pathogens and their significance in water supplies and recreational waters (partial list from WHO 2011)
supply can persist. Table 6.5 summarizes some of these concerns. Table 6.5 Waterborne pathogens and their significance in water supplies and recreational waters (partial list from WHO 2011)
Discover the truth at www.deloitte.ca/careers
Discover the truth at www.deloitte.ca/careers
Table 6.6 Disappearance rate coefficients, K, for selected microorganisms in rivers and in neutral groundwater. (Blanc & Nasser 1996, Mathess et al. 1988) Example 6.5 Dic-oFF oF BACTERIA IN A STREAM
Table 6.6 Disappearance rate coefficients, K, for selected microorganisms in rivers and in neutral groundwater. (Blanc & Nasser 1996, Mathess et al. 1988) Example 6.5 Dic-oFF oF BACTERIA IN A STREAM
important indicator organisms are listed in Table 6.7. Table 6.7 Easily cultivated organisms that are reliable indicators of fecal contamination in water (WHO 2011).
important indicator organisms are listed in Table 6.7. Table 6.7 Easily cultivated organisms that are reliable indicators of fecal contamination in water (WHO 2011).
This is a worthy challenge to raise the level of health and happiness in the world.
This is a worthy challenge to raise the level of health and happiness in the world.
Figure 7.1 The spread of sulfur dioxide aerosols released by the June 15, 1991, eruption of Mt. Pinatubo, Philippines. (Source: NASA)
Figure 7.1 The spread of sulfur dioxide aerosols released by the June 15, 1991, eruption of Mt. Pinatubo, Philippines. (Source: NASA)
Figure 7.2 Bouyant plume rise and dispersion of stack emissions. The height of plume rise depends on the temperatures of the ambient air and the gaseous emission. For power plants and many other industries the emission is warm and will rise above the stack, thus giving an effective stack height that exceeds the actual height. (Photo credit: pixabay) Figure 7.2 Bouyant plume rise and dispersion of stack emissions. The
Figure 7.2 Bouyant plume rise and dispersion of stack emissions. The height of plume rise depends on the temperatures of the ambient air and the gaseous emission. For power plants and many other industries the emission is warm and will rise above the stack, thus giving an effective stack height that exceeds the actual height. (Photo credit: pixabay) Figure 7.2 Bouyant plume rise and dispersion of stack emissions. The
Figure 7.3 is a highly simplified picture of a rectangular plume spreading downwind of the source. The plume is assumed to grow in proportion to the distance from the source. What makes this the ‘worst- case’ estimate of ground level concentration is assuming that the pollutant concentration is uniform over the cross-section. The maximum concentration of a real plume is at the centerline of the plume and the ground level concentration is less.
Figure 7.3 is a highly simplified picture of a rectangular plume spreading downwind of the source. The plume is assumed to grow in proportion to the distance from the source. What makes this the ‘worst- case’ estimate of ground level concentration is assuming that the pollutant concentration is uniform over the cross-section. The maximum concentration of a real plume is at the centerline of the plume and the ground level concentration is less.
Figure 7.3 A worst-case analysis can be done using a highly simplified picture of a dispersion plume. The release rate at the source is Q, with units of mass/time. The flux of pollutant through a cross-section at any distance x must equal the source release rate Q. As the plume moves it entrains more air and the mass of pollutant carried in 1 m? of air near the source is diluted into a larger volume. The flow of air through a cross-section of area is UWH m’/s so the dilution from the near-source concentration is by a factor of 1/UWH.
Figure 7.3 A worst-case analysis can be done using a highly simplified picture of a dispersion plume. The release rate at the source is Q, with units of mass/time. The flux of pollutant through a cross-section at any distance x must equal the source release rate Q. As the plume moves it entrains more air and the mass of pollutant carried in 1 m? of air near the source is diluted into a larger volume. The flow of air through a cross-section of area is UWH m’/s so the dilution from the near-source concentration is by a factor of 1/UWH.
The total concentration for a plume spreading in free air is
The total concentration for a plume spreading in free air is
Figure 7.4 Ideal Gaussian plume dispersion. (a) Dispersion of a plume released under stable conditions at an effective height H. The pollutant disperses laterally and vertically as the plume moves downwind. (b) A view of the plume looking down the Figure 7.4 Ideal Gaussian plume dispersion. (a) Dispersion of a plume released under stable conditions at an effective height H.
Figure 7.4 Ideal Gaussian plume dispersion. (a) Dispersion of a plume released under stable conditions at an effective height H. The pollutant disperses laterally and vertically as the plume moves downwind. (b) A view of the plume looking down the Figure 7.4 Ideal Gaussian plume dispersion. (a) Dispersion of a plume released under stable conditions at an effective height H.
Table 7.2 Lateral and vertical turbulence intensities for different wind conditions. more unstable. Table 7.2 gives typical values for different atmospheric conditions Turbulent intensities increase, especially in the vertical direction, as atmospheric conditions become
Table 7.2 Lateral and vertical turbulence intensities for different wind conditions. more unstable. Table 7.2 gives typical values for different atmospheric conditions Turbulent intensities increase, especially in the vertical direction, as atmospheric conditions become
Figure 7.5 The applicability of different models depending on the complexity of dispersion and the complexity of effect.
Figure 7.5 The applicability of different models depending on the complexity of dispersion and the complexity of effect.
issues, including tropospheric ozone, fine particles, toxics, acid deposition, and visibility degradation. Dispersion modeling uses meteorological data to characterize the dispersion of a pollutant from a source to selected downwind receptor locations. These models are used to determine compliance with National Ambient Air Quality Standards (NAAQS) and for State Implementation Plans (SIP). AERMOD is a steady-state model for continuous, buoyant plumes. Plume deposition behavior includes wet or dry deposition of particulates and/or gases. Releases may be at the surface, near surface, or elevated. It is available on the internet (USEPA 2004).
issues, including tropospheric ozone, fine particles, toxics, acid deposition, and visibility degradation. Dispersion modeling uses meteorological data to characterize the dispersion of a pollutant from a source to selected downwind receptor locations. These models are used to determine compliance with National Ambient Air Quality Standards (NAAQS) and for State Implementation Plans (SIP). AERMOD is a steady-state model for continuous, buoyant plumes. Plume deposition behavior includes wet or dry deposition of particulates and/or gases. Releases may be at the surface, near surface, or elevated. It is available on the internet (USEPA 2004).
Figure 7.6 A receptor model can be run forward or backward in time to predict source emission or conditions at the receptor. from the ambient data. teceptor models (Figure 7.6) are mathematical or statistical procedures for identifying and quantifyin: he sources of air pollutants at a receptor location. Unlike photochemical and dispersion air qualit nodels, receptor models do not use pollutant emissions, meteorological data and chemical transformatiot nechanisms. Instead, receptor models use the chemical and physical characteristics of gases and particle neasured at source and receptor to quantify source contributions to receptor concentrations. The EP/ 1as developed the Chemical Mass Balance (CMB) and UNMIX models, and also the Positive Matri ‘actorization (PMF) method. CMB fully apportions receptor concentrations to chemically distinc ource-types depending upon the source profile database. UNMIX and PMF generate source profile rom the ambient data. Case Study: Detroit Multi-Pollutant Pilot Project In each chapter about the fate of pollutants (chapters 7, 8 and 9) we will summarize one case study of a complicated modeling project. The goal is to outline the impressive capability that has grown from the very simple models that were explained earlier in the chapter. This capability has developed because of advanced understanding of mechanisms, but more important have been the availability of reliable data and massive computing power.
Figure 7.6 A receptor model can be run forward or backward in time to predict source emission or conditions at the receptor. from the ambient data. teceptor models (Figure 7.6) are mathematical or statistical procedures for identifying and quantifyin: he sources of air pollutants at a receptor location. Unlike photochemical and dispersion air qualit nodels, receptor models do not use pollutant emissions, meteorological data and chemical transformatiot nechanisms. Instead, receptor models use the chemical and physical characteristics of gases and particle neasured at source and receptor to quantify source contributions to receptor concentrations. The EP/ 1as developed the Chemical Mass Balance (CMB) and UNMIX models, and also the Positive Matri ‘actorization (PMF) method. CMB fully apportions receptor concentrations to chemically distinc ource-types depending upon the source profile database. UNMIX and PMF generate source profile rom the ambient data. Case Study: Detroit Multi-Pollutant Pilot Project In each chapter about the fate of pollutants (chapters 7, 8 and 9) we will summarize one case study of a complicated modeling project. The goal is to outline the impressive capability that has grown from the very simple models that were explained earlier in the chapter. This capability has developed because of advanced understanding of mechanisms, but more important have been the availability of reliable data and massive computing power.
Figure 7.7 The AERMOD model uses a 1 km x 1 km grid size, compared with 12 km x 12 km for the CMAQ model. This provides 144 AERMOD receptor estimates for each CMAQ estimate, and these are for different pollutants. The hybrid approach merges the two outputs and gives better resolution and better management decisions. (Wesson et al 2009, 2010; USEPA 2008) Figure 7.7 The AERMOD model uses a 1 km x 1 km grid size, compared with 12 km x 12 km for the
Figure 7.7 The AERMOD model uses a 1 km x 1 km grid size, compared with 12 km x 12 km for the CMAQ model. This provides 144 AERMOD receptor estimates for each CMAQ estimate, and these are for different pollutants. The hybrid approach merges the two outputs and gives better resolution and better management decisions. (Wesson et al 2009, 2010; USEPA 2008) Figure 7.7 The AERMOD model uses a 1 km x 1 km grid size, compared with 12 km x 12 km for the
Table 7.3 Some selected values from the benefit-cost comparison of the conventional modeling approach and the multi-pollutant hybrid model approach. (Wesson et al 2009, 2010; USEPA 2008)
Table 7.3 Some selected values from the benefit-cost comparison of the conventional modeling approach and the multi-pollutant hybrid model approach. (Wesson et al 2009, 2010; USEPA 2008)
Figure 7.8 The outputs of the dispersion model (AERMOD) and the photochemical model (CMAQ) were combined into one model output. (Wesson et al 2009, 2010; USEPA 2008)
Figure 7.8 The outputs of the dispersion model (AERMOD) and the photochemical model (CMAQ) were combined into one model output. (Wesson et al 2009, 2010; USEPA 2008)
Lakes and reservoirs are three-dimensional problems, or four-dimensional if one counts the annual Rivers are the easiest. Conditions change in one-dimension, along the length of the river. Vertical and
Lakes and reservoirs are three-dimensional problems, or four-dimensional if one counts the annual Rivers are the easiest. Conditions change in one-dimension, along the length of the river. Vertical and
Figure 8.1 Zone of mixing for a bankside discharge of pollutant may be up to three times the width of the river. At the downstream end of the mixing zone the pollutant is thoroughly mixed and diluted in the river water. Figure 8.1 Zone of mixing for a bankside discharge of pollutant may be Q, and Q, are volumetric flows of the river upstream and of the effluent, as shown in Figure 8.1. The flow after the river and effluent have mixed is Q, = Q+Q.. C,, C, and C, indicate concentrations at the three locations of interest. The pollutant will be further diluted as it moves downstream by tributaries. groundwater inflow, and overland runoff, assuming these flows do not make an additional contribution of the pollutant. groundwater inflow, and overland runoff, assuming these flows do not make an additional contribution The usual assumption is that any reactions within the mixing zone can be neglected. It isa good assumption for biological reactions, but may not be for rapid chemical oxidations. Ambient water quality criteria are usually imposed at the boundary of the mixing zone. If toxicity within the mixing zone is a problem, it may be worthwhile to discharge away from the bank or to use multiple discharge points.
Figure 8.1 Zone of mixing for a bankside discharge of pollutant may be up to three times the width of the river. At the downstream end of the mixing zone the pollutant is thoroughly mixed and diluted in the river water. Figure 8.1 Zone of mixing for a bankside discharge of pollutant may be Q, and Q, are volumetric flows of the river upstream and of the effluent, as shown in Figure 8.1. The flow after the river and effluent have mixed is Q, = Q+Q.. C,, C, and C, indicate concentrations at the three locations of interest. The pollutant will be further diluted as it moves downstream by tributaries. groundwater inflow, and overland runoff, assuming these flows do not make an additional contribution of the pollutant. groundwater inflow, and overland runoff, assuming these flows do not make an additional contribution The usual assumption is that any reactions within the mixing zone can be neglected. It isa good assumption for biological reactions, but may not be for rapid chemical oxidations. Ambient water quality criteria are usually imposed at the boundary of the mixing zone. If toxicity within the mixing zone is a problem, it may be worthwhile to discharge away from the bank or to use multiple discharge points.
Figure 8.2 Dispersion of a non-reacting pollutant spill in a river. The height of the curve indicates the concentration at three locations below the point of the injection (or spill). The peak concentration decreases with distance from the spill as turbulence mixes the pollutant with a larger volume of river water. Figure 8.2 Dispersion of a non-reacting pollutant spill in a river. The height of the The fate ofa slug injection of pollutant is different. The sharp peak in pollutant concentration that is created by the spill will be carried along by convection, but turbulent mixing along the axis of flow will also be obvious. This will mix the pollutant into a larger volume of water and decrease the peak concentration. Figure 8.2 shows that concentration pattern that will develop. If the pollutant is non-reactive the mass of pollutant remains the same in the affected volume of water, which expands with travel downstream. This dilution of the peak is important to downstream consumers, especially if the spilled pollutant is toxic, causes off tastes or odors, or is otherwise objectionable. toxic, causes off tastes or odors, or is otherwise objectionable.
Figure 8.2 Dispersion of a non-reacting pollutant spill in a river. The height of the curve indicates the concentration at three locations below the point of the injection (or spill). The peak concentration decreases with distance from the spill as turbulence mixes the pollutant with a larger volume of river water. Figure 8.2 Dispersion of a non-reacting pollutant spill in a river. The height of the The fate ofa slug injection of pollutant is different. The sharp peak in pollutant concentration that is created by the spill will be carried along by convection, but turbulent mixing along the axis of flow will also be obvious. This will mix the pollutant into a larger volume of water and decrease the peak concentration. Figure 8.2 shows that concentration pattern that will develop. If the pollutant is non-reactive the mass of pollutant remains the same in the affected volume of water, which expands with travel downstream. This dilution of the peak is important to downstream consumers, especially if the spilled pollutant is toxic, causes off tastes or odors, or is otherwise objectionable. toxic, causes off tastes or odors, or is otherwise objectionable.
‘igure 8.3a shows three pollutants decaying at different rates. The decay coefficients in these figure: rave units of 1/hour. Twenty hours travel in a river is 100 km, assuming an average velocity of 5 km/I 3 mile/h). It is unlikely that conditions will be constant for that distance, so a more realistic result may ye that shown in Figure 8.3b, where for some reason the rate coefficient changes from k = 0.05/h tc < = 0.2/h. A change like this could occur if the velocity is reduced and the removal efficiency increase: Jue to settling. The chemical might disappear due to volatilization or the river might become mor urbulent, which would increase the rate of removal. Ifthe removal mechanism is biodegradation, the rive: night enter a shallow reach where the water is warmer and benthic activity accelerates the removal rate might enter a shallow reach where the water is warmer and benthic activity accelerates the removal rate
‘igure 8.3a shows three pollutants decaying at different rates. The decay coefficients in these figure: rave units of 1/hour. Twenty hours travel in a river is 100 km, assuming an average velocity of 5 km/I 3 mile/h). It is unlikely that conditions will be constant for that distance, so a more realistic result may ye that shown in Figure 8.3b, where for some reason the rate coefficient changes from k = 0.05/h tc < = 0.2/h. A change like this could occur if the velocity is reduced and the removal efficiency increase: Jue to settling. The chemical might disappear due to volatilization or the river might become mor urbulent, which would increase the rate of removal. Ifthe removal mechanism is biodegradation, the rive: night enter a shallow reach where the water is warmer and benthic activity accelerates the removal rate might enter a shallow reach where the water is warmer and benthic activity accelerates the removal rate
Figure 8.3 (a) Exponential disappearance of three pollutants at different rates. (b) Exponential disappearance of one pollutant where the rate changes after 10 hours. 3.2.5 Oxygen Depletion in a River
Figure 8.3 (a) Exponential disappearance of three pollutants at different rates. (b) Exponential disappearance of one pollutant where the rate changes after 10 hours. 3.2.5 Oxygen Depletion in a River
Figure 8.4 Dissolved oxygen concentrations predicted for the conditions given in Example 8.3 for 10 mg/L, 20 mg/L, and 30 mg/L of pollution. More pollution drives down the dissolved oxygen to levels that become harmful to stream biota. Values for the biodegradation rate coefficient, k, are in the range of 0.05 to 0.5 day'. The reaeration rate coefficient, k,, can range from 0.25 day"' for sluggish streams to 0.45-0.7 day" for large streams of normal velocity to 1.15 day" for swift turbulent streams. The value for rapids and waterfalls is greater than 1.15. Both k, and k, depend on temperature; higher temperatures give higher k values, which means that everything happens faster.
Figure 8.4 Dissolved oxygen concentrations predicted for the conditions given in Example 8.3 for 10 mg/L, 20 mg/L, and 30 mg/L of pollution. More pollution drives down the dissolved oxygen to levels that become harmful to stream biota. Values for the biodegradation rate coefficient, k, are in the range of 0.05 to 0.5 day'. The reaeration rate coefficient, k,, can range from 0.25 day"' for sluggish streams to 0.45-0.7 day" for large streams of normal velocity to 1.15 day" for swift turbulent streams. The value for rapids and waterfalls is greater than 1.15. Both k, and k, depend on temperature; higher temperatures give higher k values, which means that everything happens faster.
Figure 8.5 Segmented river model for a biodegradable pollutant and dissolved oxygen. The first letter of the variable indicates pollutant (P) or dissolved oxygen (D), the second indicates the upstream (U) or downstream (D) end of the segment, and the number is the segment identifier.
Figure 8.5 Segmented river model for a biodegradable pollutant and dissolved oxygen. The first letter of the variable indicates pollutant (P) or dissolved oxygen (D), the second indicates the upstream (U) or downstream (D) end of the segment, and the number is the segment identifier.
Figure 8.7 Map of the Fox River, Wisconsin. The map cuts the river into two lengths, above Kaukana and below Kaukana. The shaded areas show the deposits of PCB-contaminated sediments. The numerical values are the estimated inventory of PCBs (adapted from Velleux 2001). Polychlorinated biphenyls (PCBs) were manufactured by adding chlorine to biphenyl. The resulting product was a mixture of chlorinated biphenyl groups, some with only 2 chlorine atoms attached, and some with seven or eight. Figure 8.7 shows examples of 7-Cl, 5-Cl and 4-Cl congeners. The biphenyl group has 10 positions where a Cl-atom can be attached, so there are many possible congeners. There are 169 congeners with 4 or more chlorine atoms.
Figure 8.7 Map of the Fox River, Wisconsin. The map cuts the river into two lengths, above Kaukana and below Kaukana. The shaded areas show the deposits of PCB-contaminated sediments. The numerical values are the estimated inventory of PCBs (adapted from Velleux 2001). Polychlorinated biphenyls (PCBs) were manufactured by adding chlorine to biphenyl. The resulting product was a mixture of chlorinated biphenyl groups, some with only 2 chlorine atoms attached, and some with seven or eight. Figure 8.7 shows examples of 7-Cl, 5-Cl and 4-Cl congeners. The biphenyl group has 10 positions where a Cl-atom can be attached, so there are many possible congeners. There are 169 congeners with 4 or more chlorine atoms.
Figure 8.6 (a) Volatilization is partitioning between air and water (in general between a gas and a liquid). The relative concentrations at equilibrium are defined by Henry's Law. (b) Adsorption of chemical to solids (light colored particles) and partitioning between the air and water. Figure 8.6 (a) Volatilization is partitioning between air and water (in general between a gas and a liquid). The relative
Figure 8.6 (a) Volatilization is partitioning between air and water (in general between a gas and a liquid). The relative concentrations at equilibrium are defined by Henry's Law. (b) Adsorption of chemical to solids (light colored particles) and partitioning between the air and water. Figure 8.6 (a) Volatilization is partitioning between air and water (in general between a gas and a liquid). The relative
Particles subside into the sediments during low flow but are resuspended in high flow. Some forms can volatilize. Some PCB congeners are slowly biodegradable in the presence of oxygen, but not in conditions like river sediments where there is no oxygen. Others decompose in the sediments without oxygen. The more highly chlorinated PCBs adsorb strongly to organic matter, including soil and sediment. more highly chlorinated PCBs adsorb strongly to organic matter, including soil and sediment.
Particles subside into the sediments during low flow but are resuspended in high flow. Some forms can volatilize. Some PCB congeners are slowly biodegradable in the presence of oxygen, but not in conditions like river sediments where there is no oxygen. Others decompose in the sediments without oxygen. The more highly chlorinated PCBs adsorb strongly to organic matter, including soil and sediment. more highly chlorinated PCBs adsorb strongly to organic matter, including soil and sediment.
Figure 8.8 Observed and simulated concentrations for total suspended solids (TSS) and PCBs at the De Pere dam on the Fox River, Wisconsin, from 1989 to 1996. The observed values are shown as dots and the predicted values are the solid lines. (Figures adapted from Velleux 2001) severe scouring of the river bottom. It was estimated that the Fox River was discharging 140 to 220 kg/yr into Green Bay (Lake Michigan) and the goal was to keep the PCBs out of the lake (Fitzgerald & Steur 1996). There has been no input of PCBs to the river for many years, so the PCBs are carried on sediments that accumulated years ago and are scoured from the river bottom during times of high flow. The issue was whether the contaminated sediment should be dredged from the river, left in place, or somehow covered up to restrict migration. Leaving them in place could result in intermittent transport during high flow conditions due to resuspension of surface sediments. Subsurface sediments would only be released if high flow caused severe scouring of the river bottom.
Figure 8.8 Observed and simulated concentrations for total suspended solids (TSS) and PCBs at the De Pere dam on the Fox River, Wisconsin, from 1989 to 1996. The observed values are shown as dots and the predicted values are the solid lines. (Figures adapted from Velleux 2001) severe scouring of the river bottom. It was estimated that the Fox River was discharging 140 to 220 kg/yr into Green Bay (Lake Michigan) and the goal was to keep the PCBs out of the lake (Fitzgerald & Steur 1996). There has been no input of PCBs to the river for many years, so the PCBs are carried on sediments that accumulated years ago and are scoured from the river bottom during times of high flow. The issue was whether the contaminated sediment should be dredged from the river, left in place, or somehow covered up to restrict migration. Leaving them in place could result in intermittent transport during high flow conditions due to resuspension of surface sediments. Subsurface sediments would only be released if high flow caused severe scouring of the river bottom.
\\nother problem in discharging to lakes is to calculate the spatial changes in water quality. In the simples ase, where the water is well mixed vertically, the size and shape of the mixing zone is dependent o1 he pattern, direction, duration and velocity of the wind induced current, although advection throug] he lake may play some part. The temperature difference between the discharge and the lake wate nay also play a part in controlling the degree of mixing. Thermal stratification virtually eliminates th nixing of the surface layer (epilimnion) with the deeper water (hypolimnion). Only during the sprin: nd autumn turnovers is there likely to be complete mixing of the discharge, otherwise it will tend t nix with the epilimnion. mix with the epilimnion.
\\nother problem in discharging to lakes is to calculate the spatial changes in water quality. In the simples ase, where the water is well mixed vertically, the size and shape of the mixing zone is dependent o1 he pattern, direction, duration and velocity of the wind induced current, although advection throug] he lake may play some part. The temperature difference between the discharge and the lake wate nay also play a part in controlling the degree of mixing. Thermal stratification virtually eliminates th nixing of the surface layer (epilimnion) with the deeper water (hypolimnion). Only during the sprin: nd autumn turnovers is there likely to be complete mixing of the discharge, otherwise it will tend t nix with the epilimnion. mix with the epilimnion.
Figure 8.9 Stratification in the Cherokee Reservoir of the Tennessee Valley Authority (TVA) (Courtesy of John A Gordon, 1969). The elevation is in feet (above sea level) and the disatance (in miles) is measured across the top. Tl indicates the depth of the turbine intakes and SL indicates rhe depth of the sluice. In the TVA system all water is released through the hydroturbines; none is discharged through the sluice or lost over the spillway. Figure 8.9 Stratification in the Cherokee Reservoir of the Tennessee Valley Authority (TVA) (Courtesy of John A Gordon, 1969). The
Figure 8.9 Stratification in the Cherokee Reservoir of the Tennessee Valley Authority (TVA) (Courtesy of John A Gordon, 1969). The elevation is in feet (above sea level) and the disatance (in miles) is measured across the top. Tl indicates the depth of the turbine intakes and SL indicates rhe depth of the sluice. In the TVA system all water is released through the hydroturbines; none is discharged through the sluice or lost over the spillway. Figure 8.9 Stratification in the Cherokee Reservoir of the Tennessee Valley Authority (TVA) (Courtesy of John A Gordon, 1969). The
Figure 8.10 Primary productivity and eutrophication is driven by the availability of phosphorus. Phosphorus exists in water as organic matter, particulate inorganic and organic forms, and dissolved inorganic (orthophosphate). The cycle is shown in the upper block. The graph shows how the productivity of chlorophyll (algae and plants) depends on the phosphorus concentration in the water. The aerial photo on the lower right shows an experiment in a Canadian lake. C, N & P were added on one side of a curtain; C & N (no P) were added on the other. The effect of phosphorus on eutrophication is striking. (Photo used with the kind permission of Schindler 1974). In lakes, phosphorus is the nutrient in least supply relative to plant needs. The N:P ratio in plant tissue is 10:1 to 15:1. If the ratio of N:P in water is greater than 15:1 then the lake is phosphorus limited. The P will be used up before the N is used and plant growth will be limited. Eutrophication in lakes cannot be controlled only by reducing nitrogen (Schindler et al. 2008). Reducing P will reduce primary productivity of algae, as shown by the graph of chlorophyll and P concentrations and the aerial photograph in the lower half of Figure 8.10. Figure 8.10 Primary productivity and eutrophication is driven by the availability of phosphorus. Phosphorus exists in water as organic of algae, as shown by the graph of chlorophyll and P concentrations and the aerial photograph in the
Figure 8.10 Primary productivity and eutrophication is driven by the availability of phosphorus. Phosphorus exists in water as organic matter, particulate inorganic and organic forms, and dissolved inorganic (orthophosphate). The cycle is shown in the upper block. The graph shows how the productivity of chlorophyll (algae and plants) depends on the phosphorus concentration in the water. The aerial photo on the lower right shows an experiment in a Canadian lake. C, N & P were added on one side of a curtain; C & N (no P) were added on the other. The effect of phosphorus on eutrophication is striking. (Photo used with the kind permission of Schindler 1974). In lakes, phosphorus is the nutrient in least supply relative to plant needs. The N:P ratio in plant tissue is 10:1 to 15:1. If the ratio of N:P in water is greater than 15:1 then the lake is phosphorus limited. The P will be used up before the N is used and plant growth will be limited. Eutrophication in lakes cannot be controlled only by reducing nitrogen (Schindler et al. 2008). Reducing P will reduce primary productivity of algae, as shown by the graph of chlorophyll and P concentrations and the aerial photograph in the lower half of Figure 8.10. Figure 8.10 Primary productivity and eutrophication is driven by the availability of phosphorus. Phosphorus exists in water as organic of algae, as shown by the graph of chlorophyll and P concentrations and the aerial photograph in the
Figure 8.11 A large lake or reservoir will have zones along its length and from top to bottom, as suggested in this schematic. The riverine zone at the inlet and in tributary embayments has narrow channelized basins with relatively high flow rates.The broad deep lake basin (the lacustrine zone) has low velocities, is relatively clear, and is less eutrophic. (adapted from Loucks & van Beek 2005) Figure 8.11 A large lake or reservoir will have zones along its length and from
Figure 8.11 A large lake or reservoir will have zones along its length and from top to bottom, as suggested in this schematic. The riverine zone at the inlet and in tributary embayments has narrow channelized basins with relatively high flow rates.The broad deep lake basin (the lacustrine zone) has low velocities, is relatively clear, and is less eutrophic. (adapted from Loucks & van Beek 2005) Figure 8.11 A large lake or reservoir will have zones along its length and from
Figure 8.12 Conceptual model for a lake. Often the water column will be divided layers or seqments.
Figure 8.12 Conceptual model for a lake. Often the water column will be divided layers or seqments.
Figure 8.13 Map of Hagg Lake, Oregon, showing depth contours (left) and the grid (right) that was constructed to identify rather homogeneous sections for modeling. (Cole & Wells 2002) 8.8 Fate of Pollutants in Estuaries 8.8.1 The Tidal Cycle and Water Movement
Figure 8.13 Map of Hagg Lake, Oregon, showing depth contours (left) and the grid (right) that was constructed to identify rather homogeneous sections for modeling. (Cole & Wells 2002) 8.8 Fate of Pollutants in Estuaries 8.8.1 The Tidal Cycle and Water Movement
Figure 8.14 Movement of a parcel of water down an estuary. 1 is the start position. A parcel of water moves to position 2 at the end of the ebb tide and back upstream to position 3 at the end of the flood tide. The net tidal excursion is the distance between 1 and 3. This is the movement due to fresh water advection into the estuary. Several tidal cycles may pass before a parcel of water moves from the estuary inlet to the sea. Figure 8.14 Movement of a parcel of water down an estuary. 1 is the start position. Water movement in estuaries is the complex result of a freshwater flow and a tidal oscillation, with additional momentum from the wind, and a density difference. The total distance travelled by a water particle from low water slack to high water slack and vice versa is referred to as the tidal excursion, as shown in Figure 8.14. This represents the maximum distance travelled by a water particle during the rising or falling limb of the tide. Tidal excursion is not to be confused with the distance travelled by the tide wave itself (e.g., high water), which propagates from the ocean to the end of the estuary each tide cycle, which may be up to 150 km. A parcel of water moves to position 2 at the end of the ebb tide and back upstream Several tidal cycles may pass before a parcel of water moves from the estuary inlet
Figure 8.14 Movement of a parcel of water down an estuary. 1 is the start position. A parcel of water moves to position 2 at the end of the ebb tide and back upstream to position 3 at the end of the flood tide. The net tidal excursion is the distance between 1 and 3. This is the movement due to fresh water advection into the estuary. Several tidal cycles may pass before a parcel of water moves from the estuary inlet to the sea. Figure 8.14 Movement of a parcel of water down an estuary. 1 is the start position. Water movement in estuaries is the complex result of a freshwater flow and a tidal oscillation, with additional momentum from the wind, and a density difference. The total distance travelled by a water particle from low water slack to high water slack and vice versa is referred to as the tidal excursion, as shown in Figure 8.14. This represents the maximum distance travelled by a water particle during the rising or falling limb of the tide. Tidal excursion is not to be confused with the distance travelled by the tide wave itself (e.g., high water), which propagates from the ocean to the end of the estuary each tide cycle, which may be up to 150 km. A parcel of water moves to position 2 at the end of the ebb tide and back upstream Several tidal cycles may pass before a parcel of water moves from the estuary inlet
aline coastal waters are carried into an estuary by the tides; freshwater inflows tend to wash the saltwat ack out to sea. The presence of salt in an estuary produces a longitudinal density gradient, with wat lensities around the mouth of the estuary being greater (because of higher salt concentrations) th lensities around the head of the estuary. This results in the enhancement of flood tide velocities n¢ he bed and ebb tide velocities near the surface. When averaged over a tidal cycle, this behavior lea o residual currents, in which saline water flows upstream along the bottom of the estuary and | alty, even fresh water, flows seawards near the surface. This pattern of residual flows is referred to ravitational circulation; it is driven by the gravitational forces resulting from density differences (s ‘igure 8.14b). Gravitational circulation can give rise to discharges that are 10 or 20 times greater th reshwater inflows. Gravitational circulation is an important mechanism of upstream sediment transpc nd the longitudinal dispersion of salt in estuaries. freshwater inflows. Gravitational circulation is an important mechanism of upstream sediment transport
aline coastal waters are carried into an estuary by the tides; freshwater inflows tend to wash the saltwat ack out to sea. The presence of salt in an estuary produces a longitudinal density gradient, with wat lensities around the mouth of the estuary being greater (because of higher salt concentrations) th lensities around the head of the estuary. This results in the enhancement of flood tide velocities n¢ he bed and ebb tide velocities near the surface. When averaged over a tidal cycle, this behavior lea o residual currents, in which saline water flows upstream along the bottom of the estuary and | alty, even fresh water, flows seawards near the surface. This pattern of residual flows is referred to ravitational circulation; it is driven by the gravitational forces resulting from density differences (s ‘igure 8.14b). Gravitational circulation can give rise to discharges that are 10 or 20 times greater th reshwater inflows. Gravitational circulation is an important mechanism of upstream sediment transpc nd the longitudinal dispersion of salt in estuaries. freshwater inflows. Gravitational circulation is an important mechanism of upstream sediment transport
Figure 8.15 Water density as a function of temperature and salinity.
Figure 8.15 Water density as a function of temperature and salinity.
Figure 8.16 Classification of estuaries on the basis of vertical salinity gradients.
Figure 8.16 Classification of estuaries on the basis of vertical salinity gradients.
Figure 8.17 Structure of a water quality model for Chesapeake Bay, one of the most important estuaries in the United States (U.S. EPA 2010). divided into 899 sub-sections. (USEPA 2010; www.chesapeakebay.net) seven states and the District of Columbia. There are 24 land-use classifications and the watershed is
Figure 8.17 Structure of a water quality model for Chesapeake Bay, one of the most important estuaries in the United States (U.S. EPA 2010). divided into 899 sub-sections. (USEPA 2010; www.chesapeakebay.net) seven states and the District of Columbia. There are 24 land-use classifications and the watershed is
Figure 8.18 Model results for dissolved oxygen in Chesapeake Bay for June 2009. The bottom plot shows the condition along the centerline of the estuary. There is sufficient dissolved oxygen for fish (DO > 4 mg/L) in the upper layers, but a large region of deeper water is oxygen deficient. Note the map has been turned so North is to the left instead of the top as would be normal. (Maryland Eyes on the Bay web site). Figure 8.18 Model results for dissolved oxygen in Chesapeake Bay for June 2009. The bottom plot shows the condition along the centerline of the estuary. There is sufficient dissolved oxygen for fish (DO > 4 mg/L) in the upper
Figure 8.18 Model results for dissolved oxygen in Chesapeake Bay for June 2009. The bottom plot shows the condition along the centerline of the estuary. There is sufficient dissolved oxygen for fish (DO > 4 mg/L) in the upper layers, but a large region of deeper water is oxygen deficient. Note the map has been turned so North is to the left instead of the top as would be normal. (Maryland Eyes on the Bay web site). Figure 8.18 Model results for dissolved oxygen in Chesapeake Bay for June 2009. The bottom plot shows the condition along the centerline of the estuary. There is sufficient dissolved oxygen for fish (DO > 4 mg/L) in the upper
Figure 8.19 The Deer Island Boston Harbor Project. The lower pictures are computer-generated maps showing the lack of effective dispersal of effluent from the former outfall (left-hand map) and the highly effective dilution and dispersal from the new outlet. The white tip of land is the northern tip of Cape Cod. The area outlined in white is the Stellwagen Bank. The top photo shows the Deer Island Wastewater Treatment Plant, Boston, the second largest treatment plant in the United States. The egg-shaped structures in the left foreground are anaerobic sludge digesters (12 units, 64 m tall, 3 million gallon volume). (Source: Massachusetts Water Resources Authority (MWRA.com) 2009) A recent and successful ocean outfall installation is part of the Boston Harbor Project, Figure 8.19. Boston treats its wastewater at the Deer Island Plant, the second largest treatment plant in the United States. With the former outfall locations, high pollutant concentrations were found within Boston Harbor and along the coastline immediately south. With the new outfall location, high concentrations are found only within a few kilometers of the outfall, concentrations are dramatically lower in Boston Harbor. only within a few kilometers of the outfall, concentrations are dramatically lower in Boston Harbor.
Figure 8.19 The Deer Island Boston Harbor Project. The lower pictures are computer-generated maps showing the lack of effective dispersal of effluent from the former outfall (left-hand map) and the highly effective dilution and dispersal from the new outlet. The white tip of land is the northern tip of Cape Cod. The area outlined in white is the Stellwagen Bank. The top photo shows the Deer Island Wastewater Treatment Plant, Boston, the second largest treatment plant in the United States. The egg-shaped structures in the left foreground are anaerobic sludge digesters (12 units, 64 m tall, 3 million gallon volume). (Source: Massachusetts Water Resources Authority (MWRA.com) 2009) A recent and successful ocean outfall installation is part of the Boston Harbor Project, Figure 8.19. Boston treats its wastewater at the Deer Island Plant, the second largest treatment plant in the United States. With the former outfall locations, high pollutant concentrations were found within Boston Harbor and along the coastline immediately south. With the new outfall location, high concentrations are found only within a few kilometers of the outfall, concentrations are dramatically lower in Boston Harbor. only within a few kilometers of the outfall, concentrations are dramatically lower in Boston Harbor.
Figure 8.20 The effluent tunnel and diffusers constructed in Massachusetts Bay (Boston) to serve the Deer Island Wastewater Treatment Plant. The design discharge capacity is 1,270 x 10° gal/d (4.8 x 10° m?/d). (Source: Massachusetts Water Resources Authority (MWRA.com) 2009)
Figure 8.20 The effluent tunnel and diffusers constructed in Massachusetts Bay (Boston) to serve the Deer Island Wastewater Treatment Plant. The design discharge capacity is 1,270 x 10° gal/d (4.8 x 10° m?/d). (Source: Massachusetts Water Resources Authority (MWRA.com) 2009)
loaded aquifers and lakes with atrazine and other varieties. Thelargest and most serious contaminated groundwater sites were created through ignorance, carelessness, and accidents. Dangerous chemicals were dumped without much thought about their persistence and ability to disperse. Chemicals were spilled around factory loading docks. Underground storage tanks leaked. Industrial and military wastes were dumped into pits and lagoons that did not retain the materials. Landfills slowly released leachate. Table 9.1 lists the many ways that problems can originate. Landfills slowly released leachate. Table 9.1 lists the many ways that problems can originate.
loaded aquifers and lakes with atrazine and other varieties. Thelargest and most serious contaminated groundwater sites were created through ignorance, carelessness, and accidents. Dangerous chemicals were dumped without much thought about their persistence and ability to disperse. Chemicals were spilled around factory loading docks. Underground storage tanks leaked. Industrial and military wastes were dumped into pits and lagoons that did not retain the materials. Landfills slowly released leachate. Table 9.1 lists the many ways that problems can originate. Landfills slowly released leachate. Table 9.1 lists the many ways that problems can originate.
The Problem Originates Table 9.1 Sources of Ground-Water Quality Degradation The Movement of Groundwater The flow of water in a saturated aquifer is defined by Darcy’s Law:
The Problem Originates Table 9.1 Sources of Ground-Water Quality Degradation The Movement of Groundwater The flow of water in a saturated aquifer is defined by Darcy’s Law:
Figure 9.1 The hydraulic gradient is Ah/L, expressed as m/m (ft/ft) The concentration of pollutant in the groundwater is C, usually expressed as mg/L or ug/L. The mass
Figure 9.1 The hydraulic gradient is Ah/L, expressed as m/m (ft/ft) The concentration of pollutant in the groundwater is C, usually expressed as mg/L or ug/L. The mass
Showing only one contour for concentration suggests a single chemical moving with the groundwater.
Showing only one contour for concentration suggests a single chemical moving with the groundwater.
Figure 9.2 Hypothetical plumes for a spill (a one-time source) and a continuous source o ee Pree een
Figure 9.2 Hypothetical plumes for a spill (a one-time source) and a continuous source o ee Pree een
Figure 9.4 Hypothetical plume from a chemical spill in 1950 that is to be redirected and extracted by a pump-and-treat facility There may be chemical vapor in the unsaturated zone. Figure 9.3 A pumped well redirects the flow of groundwater by altering the local hydraulic gradient
Figure 9.4 Hypothetical plume from a chemical spill in 1950 that is to be redirected and extracted by a pump-and-treat facility There may be chemical vapor in the unsaturated zone. Figure 9.3 A pumped well redirects the flow of groundwater by altering the local hydraulic gradient
facility is proposed to extract the contaminated water before reaches the city well water water supply.
facility is proposed to extract the contaminated water before reaches the city well water water supply.
be extrapolated toward future conditions once we start containment or remediation. There is no way to answer these questions without modeling. Monitoring data, even long records, cannot
be extrapolated toward future conditions once we start containment or remediation. There is no way to answer these questions without modeling. Monitoring data, even long records, cannot
Figure 9.5 Trichloroethylene (TCE) plume at the Tucson International Airport Area (TIAA) in 1987 before the Superfund cleanup began.
Figure 9.5 Trichloroethylene (TCE) plume at the Tucson International Airport Area (TIAA) in 1987 before the Superfund cleanup began.
Figure 9.6 TCE plume in groundwater at the Tucson International Airport Area Superfund Site in 2010. TCE = 5 pg/L in drinking water. The dark red areas are where the TCE plume was above 5 g/L TCE. The light red areas is where the 1,4-Dioxane plume was above 3 yg/L.The highest TCE concentrations were about 300 pg/L. Source: Arizona Dept. of Environmental Quallity. (More detailed maps of the TCE and 1,4-Dioxane plumes, that can be found by searching for TCE Plume, TIAA CERCLA Site, Tucson.)
Figure 9.6 TCE plume in groundwater at the Tucson International Airport Area Superfund Site in 2010. TCE = 5 pg/L in drinking water. The dark red areas are where the TCE plume was above 5 g/L TCE. The light red areas is where the 1,4-Dioxane plume was above 3 yg/L.The highest TCE concentrations were about 300 pg/L. Source: Arizona Dept. of Environmental Quallity. (More detailed maps of the TCE and 1,4-Dioxane plumes, that can be found by searching for TCE Plume, TIAA CERCLA Site, Tucson.)
Figure 9.7 Model predictions for TCE at the Tucson airport site with remediation (solid line) and without remediation (dotted line). The mass of TCE removed over the first eight years are shown with dots. Time = 0 is the start of the cleanup effort. Figure 9.7 Model predictions for TCE at the Tucson airport site with remediation
Figure 9.7 Model predictions for TCE at the Tucson airport site with remediation (solid line) and without remediation (dotted line). The mass of TCE removed over the first eight years are shown with dots. Time = 0 is the start of the cleanup effort. Figure 9.7 Model predictions for TCE at the Tucson airport site with remediation
Every pollution control project has a legal component. The laws are complicated. It is difficult, but necessary, to learn the applicable rules and regulations and work within the legal constraints they impose. They will dictate which chemicals and substances are to be controlled, and they constrain the quantities and concentrations that may be released into the environment. Some laws specify pollution control technology. Some prescribe analytical methods and how remedial investigations are to be done. They establish requirements for getting permits to discharge effluents and gaseous emissions, and to transport and store solid wastes. They establish requirements for getting permits to discharge effluents and gaseous emissions, and to
Every pollution control project has a legal component. The laws are complicated. It is difficult, but necessary, to learn the applicable rules and regulations and work within the legal constraints they impose. They will dictate which chemicals and substances are to be controlled, and they constrain the quantities and concentrations that may be released into the environment. Some laws specify pollution control technology. Some prescribe analytical methods and how remedial investigations are to be done. They establish requirements for getting permits to discharge effluents and gaseous emissions, and to transport and store solid wastes. They establish requirements for getting permits to discharge effluents and gaseous emissions, and to
Table 10.1 Guideline values for chemicals that are of health significance in drinking water (WHO 2011). among countries.
Table 10.1 Guideline values for chemicals that are of health significance in drinking water (WHO 2011). among countries.
Figure 10.1 is a World Health Organization map of deaths attributable to urban air pollution (WHO 2009). Outdoor urban air pollution, much of it generated by vehicles, is associated with higher rates ot! cardiovascular and respiratory diseases. Exhaust from gasoline and diesel engines contains irritating and toxic chemicals. Sulfur dioxide is corrosive. Ozone is dangerous to persons with breathing disorders (e.g., asthma). In general, particles emitted by fuel combustion processes may contain or carry more toxic compounds (e.g. metals) than particles from natural sources such as dust storms. SO, emissions are contributed mainly by thermal power generation and NO, is an indicator of vehicular pollution: although it is produced in almost all combustion reactions. Particulate matter (PM) is the most general! indicator of pollution because it receives key contributions from fossil fuel burning, industrial processes. and vehicular exhaust.
Figure 10.1 is a World Health Organization map of deaths attributable to urban air pollution (WHO 2009). Outdoor urban air pollution, much of it generated by vehicles, is associated with higher rates ot! cardiovascular and respiratory diseases. Exhaust from gasoline and diesel engines contains irritating and toxic chemicals. Sulfur dioxide is corrosive. Ozone is dangerous to persons with breathing disorders (e.g., asthma). In general, particles emitted by fuel combustion processes may contain or carry more toxic compounds (e.g. metals) than particles from natural sources such as dust storms. SO, emissions are contributed mainly by thermal power generation and NO, is an indicator of vehicular pollution: although it is produced in almost all combustion reactions. Particulate matter (PM) is the most general! indicator of pollution because it receives key contributions from fossil fuel burning, industrial processes. and vehicular exhaust.
occur during periods of sunny weather. Izone at ground level (not to be confused with the ozone layer in the stratosphere) is one of the major -onstituents of photochemical smog. It is formed by the reaction with sunlight (photochemical reaction) of pollutants such as nitrogen oxides (NO) from vehicle and industry emissions and volatile organic “ompounds (VOCs) emitted by vehicles, solvents and industry. The highest levels of ozone pollution yccur during periods of sunny weather.
occur during periods of sunny weather. Izone at ground level (not to be confused with the ozone layer in the stratosphere) is one of the major -onstituents of photochemical smog. It is formed by the reaction with sunlight (photochemical reaction) of pollutants such as nitrogen oxides (NO) from vehicle and industry emissions and volatile organic “ompounds (VOCs) emitted by vehicles, solvents and industry. The highest levels of ozone pollution yccur during periods of sunny weather.
Table 10.3 Limit Values (LV) and Target Values (TV) in the EU Air Quality Directives. environment as a whole, to be attained where possible over a given period.
Table 10.3 Limit Values (LV) and Target Values (TV) in the EU Air Quality Directives. environment as a whole, to be attained where possible over a given period.
This is a simplified hypothetical example of how a cap-and-trade system might work. Two emission sources, A and B, both emit 100,000 tonnes of CO, per year. The government gives each of them 95,00 emission allowances with one allowance representing the right to emit 1 tonne of CO,,. Both installation A and Bare, therefore, 5,000 allowances short (5%) of covering their annual CO, output. The plant owner face the same choice: either reduce their emissions by 5,000 tonnes, or purchase 5,000 allowances o1 the market. In order to decide which option to pursue, they will compare the costs of reducing thei emissions by 5,000 tonnes with the projected market price for allowances. And, as permits become mor limited and their prices rise, A and/or B might decide to invest in CO, reduction strategies instead. limited and their prices rise, A and/or B might decide to invest in CO, reduction strategies instead.
This is a simplified hypothetical example of how a cap-and-trade system might work. Two emission sources, A and B, both emit 100,000 tonnes of CO, per year. The government gives each of them 95,00 emission allowances with one allowance representing the right to emit 1 tonne of CO,,. Both installation A and Bare, therefore, 5,000 allowances short (5%) of covering their annual CO, output. The plant owner face the same choice: either reduce their emissions by 5,000 tonnes, or purchase 5,000 allowances o1 the market. In order to decide which option to pursue, they will compare the costs of reducing thei emissions by 5,000 tonnes with the projected market price for allowances. And, as permits become mor limited and their prices rise, A and/or B might decide to invest in CO, reduction strategies instead. limited and their prices rise, A and/or B might decide to invest in CO, reduction strategies instead.
Table 10.4 Pollution control instruments in China (Wikipedia; Chunmei & Zhaolan, 2010) a sustainable development strategy outlined in Table 10.4.
Table 10.4 Pollution control instruments in China (Wikipedia; Chunmei & Zhaolan, 2010) a sustainable development strategy outlined in Table 10.4.
Figure 10.2 The progress of pollution control as a result of new legislation and serious financial investments starting in the late 1960s has been impressive. waste segregation, and material reclamation. ‘able 10.5 lists the major federal legislation related to environmental protection. Mechanisms for th ontrol of toxic pollutants are contained in several federal regulations, such as the Toxic Substanc vontrol Act (PL 94-469), Comprehensive Environmental Response, Compensation, and Liability Ac PL 96-510), Resource Conservation and Recovery Act (PL 95-580), Clean Water Act (PL 95-217), Cleat \\ir Act (PL 95-95), and the Safe Drinking Water Act (PL 93-523). PL indicates Public Law. CFR is Cod f Federal Regulations. Appendix 4 explains how Federal laws and regulations are developed.
Figure 10.2 The progress of pollution control as a result of new legislation and serious financial investments starting in the late 1960s has been impressive. waste segregation, and material reclamation. ‘able 10.5 lists the major federal legislation related to environmental protection. Mechanisms for th ontrol of toxic pollutants are contained in several federal regulations, such as the Toxic Substanc vontrol Act (PL 94-469), Comprehensive Environmental Response, Compensation, and Liability Ac PL 96-510), Resource Conservation and Recovery Act (PL 95-580), Clean Water Act (PL 95-217), Cleat \\ir Act (PL 95-95), and the Safe Drinking Water Act (PL 93-523). PL indicates Public Law. CFR is Cod f Federal Regulations. Appendix 4 explains how Federal laws and regulations are developed.
S: ppmv = concentration in parts per million by volume at 25°C and 1 atm PM, indicates particles 10 ym or less in diameter on short-term averages, while others are based on an annual average. Table 10.7 Summary of the National Ambient Air Quality Standards (NAAQS) (http://www.epa.gov/air/criteria.html)
S: ppmv = concentration in parts per million by volume at 25°C and 1 atm PM, indicates particles 10 ym or less in diameter on short-term averages, while others are based on an annual average. Table 10.7 Summary of the National Ambient Air Quality Standards (NAAQS) (http://www.epa.gov/air/criteria.html)
“Superfund” is the nickname for the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Superfund provides the mechanisms for investigation, assessment, and remediation of past mistakes, in particular abandoned and contaminated sites that were not operating under a RCRA permit or where contamination is found and there is no responsible party willing or financially able to undertake cleanup. Appendix 6 is an expanded version of this summary of CERCLA. financially able to undertake cleanup. Appendix 6 is an expanded version of this summary of CERCLA.
“Superfund” is the nickname for the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Superfund provides the mechanisms for investigation, assessment, and remediation of past mistakes, in particular abandoned and contaminated sites that were not operating under a RCRA permit or where contamination is found and there is no responsible party willing or financially able to undertake cleanup. Appendix 6 is an expanded version of this summary of CERCLA. financially able to undertake cleanup. Appendix 6 is an expanded version of this summary of CERCLA.
plume scale through analysis of contaminant mass discharge, Jour. Contaminant Hydrology, vol. 126,
plume scale through analysis of contaminant mass discharge, Jour. Contaminant Hydrology, vol. 126,
Proceedings, National Alfalfa Symposium, San Diego, December 13-15, 2004. 13 pages.
Proceedings, National Alfalfa Symposium, San Diego, December 13-15, 2004. 13 pages.
Thomann, RV & Mueller, JA, 1997, Principles of Surface Water Quality Modeling and Control, Wiley, Streeter, HW & Phelps, EB 1925, A study of the pollution and natural purification of the Ohio River, III.
Thomann, RV & Mueller, JA, 1997, Principles of Surface Water Quality Modeling and Control, Wiley, Streeter, HW & Phelps, EB 1925, A study of the pollution and natural purification of the Ohio River, III.
the Lower Fox River to Green Bay, Journal of Great Lakes Research, vol. 20, pp. 416-434.
the Lower Fox River to Green Bay, Journal of Great Lakes Research, vol. 20, pp. 416-434.
Table A2.1 Partial list of Human Health Water Quality Criteria for the consumption of water & organism (USEPA 2009) For complete information go to EPA National Recommended Water Quality Criteria (http://water.epa.gov/scitech/swguidance/ standards/criteria/ current/tipnload/nrwac-3N09 naf)_ Table A2.1 Partial list of Human Health Water Quality Criteria for the consumption of water & organism (USEPA 2009) For complete
Table A2.1 Partial list of Human Health Water Quality Criteria for the consumption of water & organism (USEPA 2009) For complete information go to EPA National Recommended Water Quality Criteria (http://water.epa.gov/scitech/swguidance/ standards/criteria/ current/tipnload/nrwac-3N09 naf)_ Table A2.1 Partial list of Human Health Water Quality Criteria for the consumption of water & organism (USEPA 2009) For complete
to which an aquatic community can be exposed indefinitely without resulting in an adverse effect of a material in surface water to which an aquatic community can be exposed briefly without resulting
to which an aquatic community can be exposed indefinitely without resulting in an adverse effect of a material in surface water to which an aquatic community can be exposed briefly without resulting
Table A3.1 Partial list of the EPA Aquatic Life Criteria for Freshwater and Saltwater. CMC = Criteria Maximum Concentration = highest concentration to which an aquatic community can be exposed briefly without an unacceptable effect. CCC = Criterion Continuous Concentration = highest concentration to which an aquatic community can be exposed indefinitely without an unacceptable effect. (USEPA 2009) For complete information go to EPA National Recommended Water Quality Criteria (http://water.epa.gov/scitech/ Table A3.1 Partial list of the EPA Aquatic Life Criteria for Freshwater and Saltwater. CMC = Criteria Maximum Concentration = highest
Table A3.1 Partial list of the EPA Aquatic Life Criteria for Freshwater and Saltwater. CMC = Criteria Maximum Concentration = highest concentration to which an aquatic community can be exposed briefly without an unacceptable effect. CCC = Criterion Continuous Concentration = highest concentration to which an aquatic community can be exposed indefinitely without an unacceptable effect. (USEPA 2009) For complete information go to EPA National Recommended Water Quality Criteria (http://water.epa.gov/scitech/ Table A3.1 Partial list of the EPA Aquatic Life Criteria for Freshwater and Saltwater. CMC = Criteria Maximum Concentration = highest
Figure A4.1 Relation of three branches of the U. S. government in making and enforcing environmental laws. All major industries and consulting companies employ some people whose responsibility includes being up to date on all relevant proposed, pending, and active rules. Current law must be known to secure compliance and avoid civil or criminal penalties, and to protect the discharger’s organization from unfavorable publicity. Proposed and pending regulations must be known in order to offer comments and advice that will influence the final regulation, and to be able to make orderly plans for compliance. and advice that will influence the final regulation, and to be able to make orderly plans for compliance. The process of creating a new law or regulation offers engineers, scientists, municipalities, and industries an opportunity to influence the scope and content of the law. In fact, the development process requires the solicitation of advice through written submissions and public hearings. All three branches of Federal Government - the Legislative, Executive, and Judicial - are active in environmental regulation. The relation of the three branches of government and the opportunity for public input are shown in Figure AA 1 The process of creating a new law or regulation offers engineers, scientists, municipalities, and industries
Figure A4.1 Relation of three branches of the U. S. government in making and enforcing environmental laws. All major industries and consulting companies employ some people whose responsibility includes being up to date on all relevant proposed, pending, and active rules. Current law must be known to secure compliance and avoid civil or criminal penalties, and to protect the discharger’s organization from unfavorable publicity. Proposed and pending regulations must be known in order to offer comments and advice that will influence the final regulation, and to be able to make orderly plans for compliance. and advice that will influence the final regulation, and to be able to make orderly plans for compliance. The process of creating a new law or regulation offers engineers, scientists, municipalities, and industries an opportunity to influence the scope and content of the law. In fact, the development process requires the solicitation of advice through written submissions and public hearings. All three branches of Federal Government - the Legislative, Executive, and Judicial - are active in environmental regulation. The relation of the three branches of government and the opportunity for public input are shown in Figure AA 1 The process of creating a new law or regulation offers engineers, scientists, municipalities, and industries
characteristic limits given in Table A5.1.
characteristic limits given in Table A5.1.
long-term threat to public health. Hazardous waste sites are rated with respect to the substances involved, their tendency to migrate from the site, their toxicity, and other factors related to environmental health and safety. A site that scores high enough is placed on the National Priorities List (NPL). Sites on this list are considered to pose the most significant threat to human health or the environment. This does not mean that the site is an immediate threat to public health, but listing means that a site is considered to represent some significant, long-term threat to public health.
long-term threat to public health. Hazardous waste sites are rated with respect to the substances involved, their tendency to migrate from the site, their toxicity, and other factors related to environmental health and safety. A site that scores high enough is placed on the National Priorities List (NPL). Sites on this list are considered to pose the most significant threat to human health or the environment. This does not mean that the site is an immediate threat to public health, but listing means that a site is considered to represent some significant, long-term threat to public health.
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