Science, Ethics, and Scientif ic Ethics in the Modern World

Environmental Health Perspectives, 2009

oBjectives: Dichlorodiphenyltrichloroethane (DDT) was used worldwide until the 1970s, when concerns about its toxic effects, its environmental persistence, and its concentration in the food supply led to use restrictions and prohibitions. In 2001, more than 100 countries signed the Stockholm Convention on Persistent Organic Pollutants (POPs), committing to eliminate the use of 12 POPs of greatest concern. However, DDT use was allowed for disease vector control. In 2006, the World Health Organization and the U.S. Agency for International Development endorsed indoor DDT spraying to control malaria. To better inform current policy, we reviewed epidemiologic studies published from 2003 to 2008 that investigated the human health consequences of DDT and/or DDE (dichlorodiphenyldichloroethylene) exposure. data sources and extraction: We conducted a PubMed search in October 2008 and retrieved 494 studies. data synthesis: Use restrictions have been successful in lowering human exposure to DDT, but blood concentrations of DDT and DDE are high in countries where DDT is currently being used or was more recently restricted. The recent literature shows a growing body of evidence that exposure to DDT and its breakdown product DDE may be associated with adverse health outcomes such as breast cancer, diabetes, decreased semen quality, spontaneous abortion, and impaired neurodevelopment in children. conclusions: Although we provide evidence to suggest that DDT and DDE may pose a risk to human health, we also highlight the lack of knowledge about human exposure and health effects in communities where DDT is currently being sprayed for malaria control. We recommend research to address this gap and to develop safe and effective alternatives to DDT. key words: DDE, DDT, dichlorodiphenyldichloroethylene, dichlorodiphenyltrichloroethane, health effects, organochlorine pesticides, persistent organic pollutants.

California Agriculture, 1995

2003

This assignment is devoted to an in depth analysis of the pro-and the contra-positions in the long-standing and costly debate about the question whether to spray with DDT or not in the fight against malaria. I argue that the dilemma whether or not to spray with DDT is born out of a political agenda, hype, exaggeration and misinformation of the first order. Radical environmentalists appear to insist that DDT is a principal contributor of environmental degradation, and the major cause of death amongst wildlife and humans. Worse still, many Western people seem to be under the impression that mosquitoes cannot cause so much human misery as purported, and that malaria is caused by some kind of plant form of life, or even a virus. The proponents of DDT, on the other hand, appear to be convinced that DDT is a saviour of humankind, and argue that the horrors associated with DDT are exaggerated and baseless, as they are not backed by scientific inquiry. Proponents of DDT also believe that anything that is overused may kill, even ordinary table salt. In this assignment, both of these positions are scrutinized. On the basis of an historical overview in Chapter I of the history of the use of DDT, and the emergence of the debate about DDT in the wake of Rachel Carson's Silent Spring (1962), Chapter 2 is devoted to an evaluation of seven basic arguments against the use of DDT, while in Chapter 3 six arguments for the use of DDT are weighed. In Chapter 4 a resolution of the dilemma is proposed in which a case is made for a limited use of DDT only for indoor spraying of huts and houses against malaria mosquitoes until such time as a less dangerous alternative for DDT is found that can be used as effectively in the fight against malaria. As such, this case is informed by the strong moral conviction that we cannot allow poor people of colour to die because of a general ban on the use of DDT. Further research on this ethical debate is encouraged. Stellenbosch University http://scholar.sun.ac.za ABSTRAK Hierdie werkstuk: is toegespits op 'n in-diepte analise van die pro-en kontra-posisies in die voortslepende, asook duur debat oor die gebruik van DDT al dan nie in die bekamping van Malaria. Ek argumenteer dat die dilemma rondom die vraag of DDT gebruik moet word of nie, aangewakker word deur politieke agendas, sensasie, oordrywing en foutiewe informasie van die eerste orde. Radikale omgewingsgesindes dring oënskynlik daarop aan dat die gebruik van DDT 'n hoof-oorsaak is van die agteruitgang van die omgewing, asook 'n primêre oorsaak van dood onder wild en mense. Erger nog, dit wil voorkom of heelwat Westerse mense onder die indruk is dat muskiete nie werklik soveel menslike lyding kan veroorsaak as wat voorgegee word nie, en dat malaria eerder veroorsaak word deur 'n sekere soort plantvorm van lewe, of selfs deur 'n virus. Die voorstaanders van DDT, aan die ander kant, is klaarblyklik oortuig dat DDT 'n redder van die mensdom is, en argumenteer dat die gruwels wat geassosieer word met DDT 'n grondelose oordrywing is, aangesien dit nie deur wetenskaplike ondersoek gesteun word nie. Voorstaanders van DDT glo verder dat enige stof wat in oormaat gebruik word, die dood kan veroorsaak, selfs gewone tafelsout. In hierdie werkstuk word albei hierdie posisies krities bestudeer en bespreek. Op grond van 'n historiese oorsig in Hoofstuk 1 oor die gebruik van DDT, en die ontstaan van die debat oor DDT na aanleiding van Rachel Carson se Silent Spring (1962), word Hoofstuk: 2 gewy aan 'n evaluasie van sewe basiese argumente teen die gebruik van DDT, terwyl in Hoofstuk 3 ses argumente vir die gebruik van DDT oorweeg word. In Hoofstuk 4 word 'n voorstel gemaak vir die resolusie van die dilemma deur 'n saak uit te maak vir die beperkte gebruik van DDT, nl. slegs vir binneshuise gebruik in hutte en huise teen malaria-muskiete tot tyd en wyl 'n minder gevaarlike alternatief vir DDT gevind word wat net so effektief sal wees in die stryd teen malaria. As sulks word hierdie studie gerugsteun deur die sterk morele oortuiging dat ons nie kan toelaat dat mense van kleur sterf as gevolg van 'n algemene verbod op die gebruik van DDT nie. Verdere navorsing oor hierdie etiese debat word aangemoedig. Stellenbosch University http://scholar.sun.ac.za Firstly I would like to thank my family for their constant support throughout this project and throughout my life. My wife and kids were really magnificent with their amazing encouragement. This project would not have been possible without Professor Johan Hattingh's amazing guidance and encouragement and, for his stimulating comments which were very influential to the final outlook of the text. I really appreciated his critical comments and remarks. I thank him for making me believe in myself again. I sincerely believe that without his untiring inputs and support, this project would not have been possible. This project further meant that I had to travel to Mpumalanga and Limpopo Province to collect data, and all this thanks to Professor Kok for having ensured that my financial obligations are met for this historical research. I would also like to extend my gratitude to Tsakane Furumele, an entomologist at the Malaria Institute in Tzaneen for her amazing help in ensuring the success of this project. Stellenbosch University http://scholar.sun.ac.za TABLE OF CONTENTS CHAPTERl INTRODUCTION 1.1 1.2 1.3 Historical Background Problem Statement 7 Methodology CHAPTER2 BASIC ARGUMENT AGAINST THE USE OF DDT 2.1 Silent Spring revisited 2.2 Wildlife and DDT 2.3 Human Health and DDT 2.4 Sustainable Development Argument 2.5 Autonomy of Nature 2.6 The Ecocentric Argument 2.7 Ecology Ethic Argument 2.8 Reverence for Being 2.9 Conclusion CHAPTER3 BASIC ARGUMENTS FOR THE USE OF DDT 3.1 The general social-political context of the DDT debate 3.2 Human Health and DDT 3.3 Wildlife and DDT 3.4

Malawi Medical Journal, 2010

2013

The authors would like to thank David Gee for helping to prepare the manuscript. 'There was a strange stillness. The birds for example-where had they gone? Many people spoke about them, puzzled and disturbed. The feeding stations in the backyards were deserted. The few birds seen anywhere were moribund: they trembled violently and could not fly. It was a spring without voices ... only silence lay over the fields and woods and marsh.'

American Journal of Public Health, 2008

The use of DDT to control malaria has been a contentious practice for decades. This controversy centers on concerns over the ecological harm caused by DDT relative to the gains in public health from its use to prevent malaria. Given the World Health Organization's recent policy decisions concerning the use of DDT to control malaria, it is worth reviewing the historical context of DDT use. Ecological concerns focused on evidence that DDT ingestion by predatory birds resulted in eggs with shells so thin they were crushed by adult birds. In addition, DDT spraying to control malaria allegedly resulted in cats being poisoned in some areas, which led to increased rodent populations and, in turn, the parachuting of cats into the highlands of the island of Borneo to kill the rodents, a story that influenced the decision to ban DDT spraying. I focus on this story with the intention of grounding the current debate on lessons from the past.

Chemosphere, 2016

A total of 81 roach (Rutilus rutilus) collected from 13 southern English river sites between 2007 and 2012, were analysed for organochlorine pesticides, PCBs, PBDEs and some metals. Unexpectedly high concentrations of the banned insecticide DDT and its degradation products DDE and DDD (∑DDTs) were found in the 10 fish from the river Lee (or Lea) which averaged 88 ± 70 (standard deviation) μg/kg ww, almost 20 times higher than the average for the remaining sites (4.8 ± 3.1 μg/kg). All fish from that site exceeded the Canadian Tissue Residue Guideline (environmental quality standard) of 14 μg/kg ∑DDTs. Concentrations of the insecticides chlordane and lindane as well as copper, which is often used as a fungicide, were also elevated in fish from the Lee, though not as much as those of DDTs. A likely explanation for these observations was found in a nearby former pesticide factory, which had stopped production about three decades earlier. An extensive review of recent literature data on ...

Environmental Research, 2001

DDT contamination was investigated in soil, sediment, and chicken eggs from an endemic leishmaniasis area located in Rio de Janeiro City, Brazil. The last DDT application in this area was in 1990, for sand-By vector control. Sampling campaigns were conducted in 1997 and 1999. DDT was extracted by use of a modiAed soxhlet apparatus and analysis was performed by gas chromatography with electron capture detector. The results show that, in 1997, soil samples contained up to 351 g.kg ؊1 d.w. of DDT near the insecticide-sprayed sites. In 1999, the soil concentration decreased to 112 g.kg ؊1 d.w. of DDT. Sediments from small creeks also showed low concentrations (up to 32.9 g.kg ؊1 d.w. of DDT). Chicken eggs had, on average, 1.98 mg.kg ؊1 DDT (twice FAO's maximum residue limit), comprising 82% of p,p-DDE. Taking into account the egg results, DDT bioaccumulation is a question of concern. Considering just the egg consumption, it was estimated that DDT intake in the study area is 0.38؋10 ؊4 mg.kg ؊1 body weight.day ؊1 whereas the reference maximum dose (US EPA) is 5؋10 ؊4 mg.kg ؊1 body weight.day ؊1 . This approach can be used to estimate DDT exposure in other places where DDT contamination may be of concern, especially in places where locally produced animals and eggs are a signiAcant portion of the diet.

Ambix, 2016

Objective: To review research findings on the effects of DDT on body functions in vertebrates. Methods: The research was based on retrieval and critical review of relevant articles and abstracts cited in international and regional journals. The literature search was done on MedLine from the year 1975 to 2010. The analyses of published data on various vertebrates (birds, fish, mice, human, among others) were considered. Results: The effect of DDT on body functions is purely dependent on the degree of exposure. Whereas mild exposure (1-5mg/kg) may not have significant effects, very high concentrations (>100mg/kg) of DDT generally adversely affect the reproductive functions of animals. Eggshell quality, egg hatch-ability and health of chicks are affected by high DDT exposure. Very high DDT levels may increase the chances of spontaneous abortion and preterm birth, which is one of the main causes of infant mortality in humans. The health of a growing foetus and infant may also be compromised by DDT transfer from an exposed mother through the placenta and breast milk. The DDT affects the estrous cycle of exposed animals by altering the hormonal functions. In male rats, DDT has been observed to alter spermatogenesis and reduce aggression behaviour. However the effect in higher male animals has not been clearly elucidated. Conclusion: DDT exposure has drastic effects on reproductive functions in vertebrates, and safer alternatives should be considered rather than reintroducing DDT as a control agent for mosquitoes as has been suggested recently.