Polluted creek

The present examination investigates the pertinence of response surface method related to the Box-Behnken Design to statistically streamline the electro coagulation system to ejection of Dicofol pesticide from misuse water. The effect of three parameters: electrolysis time (20-180 min), pH (3-11), voltage (3-19 volts), was considered. The quadratic backslide show displayed a respectable relationship amongst foreseen and trial values (R 2 =0.98). ANOVA studies (p-regard) attested adequacy of backslide illustrate. Likewise, a low value (0.18) of coefficient of assortment showed a more elevated amount of precision and relentless nature of examinations. Response surfaces showed a colossal impact of electrolysis time, voltage and pH on the removal of Dicofol from liquid course of action. The perfect conditions obtained were electrolysis time (124 min), Voltage (15 volts) and pH (5.2) to fulfill departure of Dicofol. The proposed plot associations may ended up being a profitable mechanical assembly in arranging the business plant for the electro coagulation process.

This paper presents the residue levels of organochlorine, organophosphate pesticides and herbicides in agricultural soils from Delhi region. Among OCPs, HCH, DDT endosulphan and dieldrin ranged between <0.01-104.14 ng g-1 , <0.01-15.79 ng g-1 , <0.01-7.57 ng g-1 and <0.01-2.38 ng g-1 , respectively. The concentration of OPPs ranged from <0.01-20.95 ng g-1 , ND-3.92 ng g-1 , ND-31.73 ng g-1 , ND-6.46 ng g-1 and ND-6.46 ng g-1 for phosphomidon, monocrotophos, chlorpyriphos, quinolphos and ethion, respectively. Pendimethalin (0.27 ng g-1) was the dominant herbicides followed by butachlor (0.19 ng g-1), and fluchloralin (0.05 ng g-1). Data showed the region was contaminated by technical DDT and technical HCH mixture. The study reveals that the level of some organochlorine pesticides in agricultural soils is a matter of concern for future food chain accumulation and human health so; regular investigation of pesticide residues is recommended on soil health and contamination levels.

Pakistan is an agro-economy country where hexachlorocyclohexane (HCH) pesticides are being used to improve crop productivity, as a result the risk of contamination of soil and sediment has been increased. HCH exhibits all the characteristics of persistent organic pollutants (POP), and was therefore added to the list of ‘new POPs’ in 2009. This review report revealed that the major rivers of Pakistan such as the Indus Basin, River Ravi, River Chenab and their tributaries all are contaminated with HCH and the highest residual concentration (4,090 ng/g) was detected in a pesticide burial ground in Hyderabad city. Major sources of HCH contamination were identified as agricultural runoff, discharge of untreated industrial effluents and surface runoff. In order to manage HCH pollution, various ex-situ and in-situ remediation techniques along with their merits and demerits are thoroughly reviewed. Among these, microbial bioremediation is a low cost, environment friendly, effective in-situ ...

The present study was performed for the period of one year from June 2012 to May 2013 in order to understand the level of toxic heavy metals in the water of Mahim Creek near Mumbai. It was observed that the annual average concentration of heavy metals like Pb, Cd, Cr, Fe, Zn, Cu and Ni and Hg was found to be 0.68, 0.28, 0.15, 0.04, 2.93, 0.64, 1.29 and 0.31 ppm respectively. The average concentrations of Hg and Pb were found to be above the maximum permissible limit of 0.01 ppm and 0.1 ppm respectively set for inland surface water by Central Pollution Control Board (CPCB) of India. The results suggest that there is a need to have such regular scientific monitoring for longer time period in order to understand the variation in level of these toxic heavy metals discharged in to the creek water. It is feared that the existing problem if ignored may increase the pollution problem of the creek due to the toxic heavy metals resulting in threat to the biological life of an aquatic ecosyste...

Pemba Island which is part of Zanzibar in the United Republic of Tanzania, is situated between latitude of 34°1′0′′N and 5°14′32′′S, and longitude of 118°8′0′′ and 39° 48′7′′E. It has a population of 432,100 people of which 70% depends on agricultural activities as their main livelihood option (NBS, 2012). The island is partly undulating with many crevices and valleys and about 30 % of the land is not suitable for agriculture activities as it is covered by coral rag soil, especially along east coast. Agriculture in Pemba is characterised by a wide variety of intricate mixed cropping systems dominated by rice growing activities. The rice farming activities are carried out within hydromorphic valleys located along western and southern part of the island. The suitability of the hydromorphic valleys for rice farming is attributed by high soil fertility and presence of permanent and temporary running streams assisted by very shallow water table. Rice is the most preferred food in Zanzibar and its annual demand is estimated between 90,000 to 120,000 tons(MALNR, 2017). The major policy of rice farming in Zanzibar has been self-sufficiency in rice and a number of initiatives have been taken by the Zanzibar Government to increase the production. Despite subsidies such as provision of tractor services, rice development projects, irrigation schemes and other input into the sector, rice production is far below the demand. The production is estimated to provide 20 % of the total demand (MALNR, 2017). Declining yields and Population growth make it extremely difficult to even maintain the production levels and therefore self sufficient in rice production has become flying target. The decline in rice production is attributed by number of factors including small scale farming that uses low technology and frequent pest outbreak. The pest problems in Pemba are typical to sub-humid tropical agriculture and oftenly observed in every season. Consequently pesticides are routinely used to reduce possible losses due to pest and the intensity of pesticide use increase during the pest outbreak period.Common pests that have been reported to affect rice farming are rice hispa beetle

Pakistan is an agro-economy country where hexachlorocyclohexane (HCH) pesticides are being used to improve crop productivity, as a result the risk of contamination of soil and sediment has been increased. HCH exhibits all the characteristics of persistent organic pollutants (POP), and was therefore added to the list of ‘new POPs’ in 2009. This review report revealed that the major rivers of Pakistan such as the Indus Basin, River Ravi, River Chenab and their tributaries all are contaminated with HCH and the highest residual concentration (4,090 ng/g) was detected in a pesticide burial ground in Hyderabad city. Major sources of HCH contamination were identified as agricultural runoff, discharge of untreated industrial effluents and surface runoff. In order to manage HCH pollution, various ex-situ and in-situ remediation techniques along with their merits and demerits are thoroughly reviewed. Among these, microbial bioremediation is a low cost, environment friendly, effective in-situ ...

The present examination investigates the pertinence of response surface method related to the Box-Behnken Design to statistically streamline the electro coagulation system to ejection of Dicofol pesticide from misuse water. The effect of three parameters: electrolysis time (20-180 min), pH (3-11), voltage (3-19 volts), was considered. The quadratic backslide show displayed a respectable relationship amongst foreseen and trial values (R 2 =0.98). ANOVA studies (p-regard) attested adequacy of backslide illustrate. Likewise, a low value (0.18) of coefficient of assortment showed a more elevated amount of precision and relentless nature of examinations. Response surfaces showed a colossal impact of electrolysis time, voltage and pH on the removal of Dicofol from liquid course of action. The perfect conditions obtained were electrolysis time (124 min), Voltage (15 volts) and pH (5.2) to fulfill departure of Dicofol. The proposed plot associations may ended up being a profitable mechanical assembly in arranging the business plant for the electro coagulation process.

Different kinds of fishing gears used along the Ulhas River estuary (URE) were studied for their make and methods of operation. Most of the gears were designed indigenously to suit the availability of the amenable fishery species. The overall chronospatial pattern of frequency of gears operation was obtained using PRIMER v6 software. The use of gears was most frequent and diverse towards the lower reaches of the estuary. Late post-monsoon season was the most affluent in gear frequency. The important fishing methods used along the URE was &amp;#39;vana&amp;#39; (barrier net), &amp;#39;busa&amp;#39; (surface gill-net), &amp;#39;dol&amp;#39; (stationary bag net) and &amp;#39;malli&amp;#39; (basin method for capturing mudskippers on mud-flats). The fishing was carried for subsistence or artisanal levels at major while commercial fishing was highly reduced in URE. The reduced mesh sizes of the ambient gears portray the size of the species sought which depicted the threatening status of overall condition of fisheries in URE and requires a special attention for its rejuvenation.

Ulhas river estuary is subjected to heavy pollution due to the industrial and residential belts established along its either banks incurring huge amount of non-point and point pollution sources. Ambient hydrological conditions assessed during July 2005 to May 2006 and anthropogenic stresses are critical therefore leading to the decline in the fishery diversity as compared to earlier records. The abundant main fin-fishery species were replaced by the pollution tolerant species in due course of time. Several fin-fisheries have been obliterated in the estuary. Majority of the fishermen have abandoned the fishing practices due to non-productive status of the Ulhas river estuary fin-fisheries. The species diversity and species richness of the present diversity were conducive of the former observations.

The organochlorines (OClPs) and organophosphates (OPPs) pesticides in surface and ground water having intensive agriculture activity were investigated to evaluate their potential pollution and risks on human health. As per USEPA 8081 B method, liquid-liquid extraction followed by Gas-Chromatographic technique with electron capture detector and mass selective detector (GC-MS) were used for monitoring of pesticides. Among organochlorines, α,β,γ,δ HCH’s, aldrin, dicofol, DDT and its derivatives, α,β endosulphan’s and endosulphan-sulphate were analysed; dichlorovos, ethion, parathion-methyl, phorate, chlorpyrifos and profenofos were determined among organophosphates. As compared to ground water, higher concentrations of OClPs and OPPs were found in surface water. Throughout the monitoring study, α - HCH (0.39 μg/L in Amravati region),α - endosulphan (0.78 μg/L in Yavatmal region), chlorpyrifos (0.25 μg/L in Bhandara region) and parathion-methyl (0.09 μg/L in Amravati region) are frequen...

Fish constitutes an important and cheap source of animal protein to human beings and a large number of people depend on fish and fishing activities for their livelihood. Increasing human influences through heavy metal pollution have however, led to the depletion of our fish resources and substantial reduction in the nutritive values. The danger of these heavy metals is their persistent nature as they remain in the biota for long period of time when they are released into the environment. As a result of the heavy metal pollution several endemic fish species have become threatened. Realizing this, assessment of heavy metals in the tissues of fish species is increasingly gaining ground throughout the world. Considering the above facts the current research was carried out at Vashi Creek. The creek is highly polluted and thus the fishes from this creek were selected which includes Harpadon nehereus, Mugil spp, Terapon theraps, Mystus gulio, Macrobrachium idae, Clupeidae and Tilapia mossa...

Fish constitutes an important and cheap source of animal protein to human beings and a large number of people depend on fish and fishing activities for their livelihood. Increasing human influences through heavy metal pollution have however, led to the depletion of our fish resources and substantial reduction in the nutritive values. The danger of these heavy metals is their persistent nature as they remain in the biota for long period of time when they are released into the environment. As a result of the heavy metal pollution several endemic fish species have become threatened. Realizing this, assessment of heavy metals in the tissues of fish species is increasingly gaining ground throughout the world. Considering the above facts the current research was carried out at Vashi Creek. The creek is highly polluted and thus the fishes from this creek were selected which includes Harpadon nehereus, Mugil spp, Terapon theraps, Mystus gulio, Macrobrachium idae, Clupeidae and Tilapia mossa...

Agricultural intensification helps to uplift socio-economic condition of farmers but the overuse of pesticides in farmland cause health and environmental problems. It is assumed that agricultural intensification contaminates river water and soil via pesticides applications. However, there are very limited studies on quality assessment of river water in reference to pesticide pollution in Nepal. The aim of the current study is to investigate the level of pesticide contamination in soil and water of agricultural intensive area (Ansikhola watershed, Kavre, Nepal). The analysis is focused mainly on organochlorine and organophosphorous as these two groups are most commonly used in Nepal. Endosulfan, iprobenfos, monochrotofos, mevinphos and butamifos are detected in water samples where as cypermethrin, dichlorvos, and cyafluthrin are detected in soil samples. The concentration up to 2 ppb has been reported in this study.

Estuaries with mangroves and mudflats have high aquatic biodiversity. These ecosystems play important roles as sheltering, feeding, nursery and spawning grounds for finfish and shellfish (Vidthayanon & Premcharoen 2002). Some species occur both as juveniles and as adults in these areas while others move as adults to other biotopes such as deep zones in the coral reef and vice versa (Van der Velde et al. 1995). Kambona (1974) observed that commercial fisheries yield in the Indian Ocean are based mainly on coastal species particularly migratory pelagic and demersal species from estuaries and coral reefs. Highly detrimental fishing methods such as the use of dynamite and beach seines as well as indiscriminate shell fish collection have contributed to the depletion of various coastal resources on the Indian Ocean coast (Matthes 1974). Understanding the assemblages of organisms and how they change in species numbers and abundance depending on existing biotopes is of great interest to eco...

Pakistan is an agro-economy country where hexachlorocyclohexane (HCH) pesticides are being used to improve crop productivity, as a result the risk of contamination of soil and sediment has been increased. HCH exhibits all the characteristics of persistent organic pollutants (POP), and was therefore added to the list of &#39;new POPs&#39; in 2009. This review report revealed that the major rivers of Pakistan such as the Indus Basin, River Ravi, River Chenab and their tributaries all are contaminated with HCH and the highest residual concentration (4,090 ng/g) was detected in a pesticide burial ground in Hyderabad city. Major sources of HCH contamination were identified as agricultural runoff, discharge of untreated industrial effluents and surface runoff. In order to manage HCH pollution, various ex-situ and in-situ remediation techniques along with their merits and demerits are thoroughly reviewed. Among these, microbial bioremediation is a low cost, environment friendly, effective ...

Estuaries with mangroves and mudflats have high aquatic biodiversity. These ecosystems play important roles as sheltering, feeding, nursery and spawning grounds for finfish and shellfish (Vidthayanon & Premcharoen 2002). Some species occur both as juveniles and as adults in these areas while others move as adults to other biotopes such as deep zones in the coral reef and vice versa (Van der Velde et al. 1995). Kambona (1974) observed that commercial fisheries yield in the Indian Ocean are based mainly on coastal species particularly migratory pelagic and demersal species from estuaries and coral reefs. Highly detrimental fishing methods such as the use of dynamite and beach seines as well as indiscriminate shell fish collection have contributed to the depletion of various coastal resources on the Indian Ocean coast (Matthes 1974). Understanding the assemblages of organisms and how they change in species numbers and abundance depending on existing biotopes is of great interest to eco...

The mudskipper fishery study from Ulhas river estuary in the vicinity of Thane city, India was assessed for its status with a special reference to the biology of Boleophthalmus dussumieri (Cuv. & Val.) in 2005. The seasonwise hydrology, anthropogenic activities analyses depicted a great stress on the ambient species. Gobioide species were observed to be declining due to the heavy pollution in the Ulhas river estuary. The impact was high in late post monsoon season.

generously during the project period. He also expresses his gratefulness especially to his colleagues, fishermen community, the non-teaching staff and research students Mr. Sameer and Mr. Adesh from Advance Study Centre of the B. N. Bandodkar college of Science without their help project wouldn't have been a success. Author also acknowledges with thanks to everyone who was involved in the project work, directly or indirectly.

Ulhas river estuary is subjected to heavy pollution due to the industrial and residential belts established along its either banks incurring huge amount of non-point and point pollution sources. Ambient hydrological conditions assessed during July 2005 to May 2006 and anthropogenic stresses are critical therefore leading to the decline in the fishery diversity as compared to earlier records. The abundant main fin-fishery species were replaced by the pollution tolerant species in due course of time. Several fin-fisheries have been obliterated in the estuary. Majority of the fishermen have abandoned the fishing practices due to non-productive status of the Ulhas river estuary fin-fisheries. The species diversity and species richness of the present diversity were conducive of the former observations.

The fish diversity and associated environment of 12 strategically selected intertidal stations along the extremely polluted Thane creek on the west coast of India were studied for a year and compared with past available data to investigate changes in the creek ecology due to various anthropogenic activities like industrial, domestic, and solid waste disposal along with land reclamation. Hydro-sedimentological investigations revealed enhancement of total nitrogen (TN) and organic carbon (C org) load and hypoxic levels of dissolved oxygen (DO) over the years. Silt component of sediment was increasing, with proportionate decrease in clay due to various anthropogenic disturbances. 12 species of fish were recorded along the entire length of the creek with dominance of only 5 species that occurred throughout the year, namely Mugil cephalus, Mystus gulio, Mystus shingala, Tilapia mossambica and Scylla serrata where as the other fishes were rare in their occurrence. A comparison with the pa...

The coastal areas are highly dynamic and complex with a variety of ecosystems. Nearly 25% of people of the country live in these coastal areas largely depending on coastal waters for their livelihood, and highly populated cites are located on coastal area. These regions are experiencing rapid development and therefore, hectic human interference with the environment.

Exposure to mercury has shown to cause neurological and kidney impairment. Earlier studies have shown that waters and thus most of the fish of Ulhas river estuary in Maharashtra are contaminated with Hg. The study carried out on fish consumption pattern confirmed fish to be a staple item in the diet of indigenous fish-eating populations of Alimgarh village who consume large quantities of contaminated fish from Ulhas river estuary. A study on the dietary intake of mercury through fish consumption in Alimgarh villagers revealed a range of 0.0029 µg/kg body wt/week and 11.434 µg/kg body wt/ week with an average of 3.146 + 2.27 µg/kg body wt/week in this population. Alimgarh village thus had 40% of the populations exceeding the PTWI limit of 3.3 µg/kg body weight /week as proposed by JECFA in 2003, forcing this population to be categorized under vulnerable group with a risk of Hg poisoning. High consumption of carnivorous fish like Mystus spp. and Scylla serrata, high rate of fish consumption and a high frequency of consumption in this population were the factors influencing high dietary intake of Hg in this population. In order to place them within the safe limit of 3.3 µg/kg body wt/week, it is found necessary to limit the consumption of carnivorous fish like Mystus spp. and Scylla serrata. However, people can relish on several fish meals of herbivorous fish like prawns and Tilapia spp. while fishes like Mugil spp., and Gobius spp. should be consumed in moderation.

the vicinity of Mumbai are highly polluted owing to the heavy load of industrial pollutants and sewage discharged in to them. Size related studies on mercury accumulation in Mugil cephalus were carried out in two locations, Wehele along Ulhas river estuary and Vittawa along Thane creek. Mercury levels were found in proportion with the length of fish. The maximum safe size for consumption of M.cephalus from Wehele is 14.5 cms and that from Vittawa is 16.6 cms. In the size-related Hg accumulation in fish from Wehele, statistical evaluation by regression analysis showed best fit equation Y = -0.78689 + 0.090649 X with multiple correlation coefficient R = 0.9323 whereas in Vittawa, the best fit equation obtained by regression analysis was Y = -0.7052 + 0.072708 X and a multiple correlation co-efficient R = 0.9874 was obtained. The rate of mercury bioaccumulation was found to be same in both locations. However, the slight variation observed in the process of mercury bioaccumulation was r...

Exposure to mercury has shown to cause neurological and kidney impairment. Earlier studies have shown that waters and thus most of the fish of Ulhas river estuary in Maharashtra are contaminated with Hg. The study carried out on fish consumption pattern confirmed fish to be a staple item in the diet of indigenous fish-eating populations of Alimgarh village who consume large quantities of contaminated fish from Ulhas river estuary. A study on the dietary intake of mercury through fish consumption in Alimgarh villagers revealed a range of 0.0029 µg/kg body wt/week and 11.434 µg/kg body wt/ week with an average of 3.146 + 2.27 µg/kg body wt/week in this population. Alimgarh village thus had 40% of the populations exceeding the PTWI limit of 3.3 µg/kg body weight /week as proposed by JECFA in 2003, forcing this population to be categorized under vulnerable group with a risk of Hg poisoning. High consumption of carnivorous fish like Mystus spp. and Scylla serrata, high rate of fish consu...

Thirteen persistent organic pesticides were investigated in the sediments of Vasai Creek near Mumbai to evaluate their pollution levels and potential risks. It was observed that ΣOCPs level was in the range of 597–1538 ng/g dw, with an average value of 1115.25 ng/g dw. The level of ΣOPPs was in the range of 492–1034 ng/g dw, with an average value of 798.15 ng/g dw. The values o,p′-DDT/p,p′-DDT ratio gives an indication of use of technical DDT as the prime source of DDT, while the α/γ-BHC ratio indicate that BHCs in study area might have been received from fresh lindane. The results of an ecological risk assessment showed that sediment bound organic pesticides are of more ecotoxicological concern as they might create adverse ecological risk to the marine breeding habitats. These pesticides residues may get remobilize and released to overlying waters creating adverse effects on terrestrial and aquatic organisms.

Different kinds of fishing gears used along the Ulhas River estuary (URE) were studied for their make and methods of operation. Most of the gears were designed indigenously to suit the availability of the amenable fishery species. The overall chronospatial pattern of frequency of gears operation was obtained using PRIMER v6 software. The use of gears was most frequent and diverse towards the lower reaches of the estuary. Late post-monsoon season was the most affluent in gear frequency. The important fishing methods used along the URE was 'vana' (barrier net), 'busa' (surface gill-net), 'dol' (stationary bag net) and 'malli' (basin method for capturing mudskippers on mud-flats). The fishing was carried for subsistence or artisanal levels at major while commercial fishing was highly reduced in URE. The reduced mesh sizes of the ambient gears portray the size of the species sought which depicted the threatening status of overall condition of fisheries in URE and requires a special attention for its rejuvenation.

Exposure to mercury has shown to cause neurological and kidney impairment. Earlier studies have shown that waters and thus most of the fish of Ulhas river estuary in Maharashtra are contaminated with Hg. The study carried out on fish consumption pattern confirmed fish to be a staple item in the diet of indigenous fish-eating populations of Alimgarh village who consume large quantities of contaminated fish from Ulhas river estuary. A study on the dietary intake of mercury through fish consumption in Alimgarh villagers revealed a range of 0.0029 µg/kg body wt/week and 11.434 µg/kg body wt/ week with an average of 3.146 + 2.27 µg/kg body wt/week in this population. Alimgarh village thus had 40% of the populations exceeding the PTWI limit of 3.3 µg/kg body weight /week as proposed by JECFA in 2003, forcing this population to be categorized under vulnerable group with a risk of Hg poisoning. High consumption of carnivorous fish like Mystus spp. and Scylla serrata, high rate of fish consu...

The present study was performed for the period of one year from June 2012 to May 2013 in order to understand the level of toxic heavy metals in the water of Mahim Creek near Mumbai. It was observed that the annual average concentration of heavy metals like Pb, Cd, Cr, Fe, Zn, Cu and Ni and Hg was found to be 0.68, 0.28, 0.15, 0.04, 2.93, 0.64, 1.29 and 0.31 ppm respectively. The average concentrations of Hg and Pb were found to be above the maximum permissible limit of 0.01 ppm and 0.1 ppm respectively set for inland surface water by Central Pollution Control Board (CPCB) of India. The results suggest that there is a need to have such regular scientific monitoring for longer time period in order to understand the variation in level of these toxic heavy metals discharged in to the creek water. It is feared that the existing problem if ignored may increase the pollution problem of the creek due to the toxic heavy metals resulting in threat to the biological life of an aquatic ecosystem. From the results of the present investigation it seems that the time has come to move towards ecosystem specific discharge standards to maintain the health and productivity of natural resources on which the majority of human population is dependent.

Shrimps are very important part of the export economy of Pakistan. They share about 60 % the total exports
of the sea food. For the studies of shrimp health, the length-weight studies are critical for the evaluation of the shrimp
stocks. In this paper an attempt has been made to explore the Length-weight relationships of the shrimps at the creeks
zone of Sindh coast (the study area). Furthermore, the impacts of seasonal change on the growth of shrimps (length and
weight treated as parameter) have been evaluated. The main objective of this study is to analyze the seasonal and
spatial pattern of growth and condition of the selected shrimp species. For this purpose, three most abundant shrimp
species Penaeus indicus, Metapenaeus affinis and Exopalaemon styliferus have been selected out of 30 found at the
coastal creeks areas of Sindh, Pakistan from April 2013 to January 2014. Pre and Post-Monsoon seasonal changes
were analyzed through Geographic Information Science (GIS) and universally accepted equation for LWRs logW =
alogLb were applied on three species selected. It has been found that post-monsoon is the ideal period for shrimp catch
for three species. LWRs (growth pattern) found stable in Penaeus indicus and Metapenaeus affinis while predicting an
alarming deteriorated situation for Exopalaemon styliferus at creeks zone.
ACKNOWLEDGEMENTS
We would like to express our thanks to Mr. Paul
Fanning, Chief Technical Advisor of Food and
Agricultural Organization (FAO) and Marine Fisheries
Department (MFD) and Government of Sindh for the
accessibility of the collected data from the field
surveys. We are also thankful to WWF-Pakistan for the
financial assistance for the execution of the GIS
project. Very special thanks to Ms. Shahla Siddiqui
Cooperative Teacher from Department of Statistics,
University of Karachi for her technical assistance in the
quantitative analysis of data.

The paper reports PHc contamination in water, sediment and biota of the coastal area of Bassein-Mumbai in relation to relatively less polluted sites (Dabhol and Ratnagiri) off the west coast of India. To facilitate inter-comparison three standards have been used though the results are reported in terms of SAM (Residue of Saudi Arabian Mix crude). The concentration of PHc in water off Bassein-Mumbai varies widely (2.9-39.2 lg l À1 ) as compared to the average baseline (2.8 lg l À1 ) with higher values generally confined to creeks and estuaries. The higher concentration of PHc in the bottom water of shallow areas is attributed to the contribution from the sediment-associated petroleum residue. High concentration of PHc in the surficial sediment of inshore area Ratnagiri (107.7 ppm, dry wt) is perhaps the remnants of an oil spill that occurred in the Bombay High region on May 17, 1993. The majority of values of PHc concentration in the surficial sediment of the Bassein-Mumbai region exceed 15 ppm (dry wt) against the expected background (<3 ppm, dry wt) and the trend is indicative of transfer of PHc loads from the inshore areas to the open-shore sediments. The PHc concentration of 0.8-2.6 ppm (dry wt) in sediment deposited prior to the first global commercial use of petroleum in core R5 represents the biogenic background. Based on the period of industrialisation and the horizon of PHc accumulation, a sedimentation rate of 0.2 and 1.0 cm y À1 respectively is estimated for cores U11 and U12. Substantial increase in the concentration of PHc in sediment after 1950 in cores T8 and T10 correlates well with the establishment of refineries on the western shore of the Thane Creek in 1955-1960. A minor peak in most cores in the top 10 cm sediment probably results from biological transfer of PHc lower into the sediment by benthic organisms. Excess of PHc retained in the sediment of the Bassein-Mumbai region over the biogenic background is estimated at 40,000 t. The PHc residues (1.8-10.8 ppm, wet wt) in fish caught off Bassein-Mumbai do not suggest bioaccumulation.

The fish diversity and associated environment of 12 strategically selected intertidal stations along the extremely polluted Thane creek on the west coast of India were studied for a year and compared with past available data to investigate changes in the creek ecology due to various anthropogenic activities like industrial, domestic, and solid waste disposal along with land reclamation. Hydro-sedimentological investigations revealed enhancement of total nitrogen (TN) and organic carbon (C org ) load and hypoxic levels of dissolved oxygen (DO) over the years. Silt component of sediment was increasing, with proportionate decrease in clay due to various anthropogenic disturbances. 12 species of fish were recorded along the entire length of the creek with dominance of only 5 species that occurred throughout the year, namely Mugil cephalus, Mystus gulio, Mystus shingala, Tilapia mossambica and Scylla serrata where as the other fishes were rare in their occurrence. A comparison with the past literature for the study area revealed decline in the fish diversity. As per the energy transfer theory, it was observed that the benthos in the study area can support an average fishery yield of at least 256937.2 kg/year (i.e. 21411.433 kg/month). This however is not fully utilized because the fishes were found to feed mostly on phytoplankton and the locals also reported very poor fishery catch in the creek.

Ulhas river estuary is subjected to heavy pollution due to the industrial and residential belts established along its either banks incurring huge amount of non-point and point pollution sources. Ambient hydrological conditions assessed during July 2005 to May 2006 and anthropogenic stresses are critical therefore leading to the decline in the fishery diversity as compared to earlier records. The abundant main fin-fishery species were replaced by the pollution tolerant species in due course of time. Several finfisheries have been obliterated in the estuary. Majority of the fishermen have abandoned the fishing practices due to non-productive status of the Ulhas river estuary fin-fisheries. The species diversity and species richness of the present diversity were conducive of the former observations.