Washington, DC–(ENEWSPF)–October 28, 2013. Scientists at Washington State University (WSU), in a laboratory study, determined that exposure to the insecticide DDT —banned in the U.S. since 1972, but still used today in developing countries for malaria abatement programs—impacts multiple generations, ultimately contributing to obesity three generations down the line. The study, published in the journal BMC Medicine, provides the scientific community with new information on multi-generational impacts of pesticide exposure.
Lead researcher Michael Skinner, PhD., professor of biological sciences at WSU, and colleagues exposed pregnant rats to DDT to determine the long-term impacts to health across generations. The study, Ancestral dichlorodiphenyltrichloroethane (DDT) exposure promotes epigenetic transgenerational inheritance of obesity, finds that the first generation of rats’ offspring developed severe health problems, ranging from kidney disease, prostate disease, and ovary disease, to tumor development. Interestingly, by the third generation more than half of the rats have increased levels of weight gain and fat storage. In other words, the great grandchildren of the exposed rats are much more likely to be obese.
“Therefore, your ancestors’ environmental exposures may influence your disease development even though you have never had a direct exposure,” the study finds.
Previous studies have demonstrated that exposure to chemicals, including fungicides, dioxins, and other endocrine disruptors, can have severe health impacts on offspring. This study builds on a history of research showing that DDT can continue to impact health across generations. Evidence of multi-generational impacts from pesticide exposure is not isolated to laboratory animals. A 2007 scholarly review, entitled Pesticides, Sexual Development, Reproduction and Fertility: Current Perspective and Future Direction, written by Theo Colborn, PhD. and Lynn Carroll, PhD, pointed to studies linking the legacy chemical DDT to transgenerational health effects.
DDT is an organochlorine pesticide that was banned for most uses in the U.S. in 1972 due to its persistent and highly toxic nature. DDT was widely used to control mosquitoes for malaria abatement, as well as in agriculture. Despite the fact that DDT was banned in the U.S. more than 40 years ago, concentrations of this toxic chemical’s major metabolite, DDE, have remained alarmingly high in many ecosystems, including surface waters, the Arctic, and even U.S. national parks. A recent study found concentrations of DDE river otters of the Illinois River, at levels higher than those detected in otters only 20 years ago. This is because the chemicals DDT/DDE are considered persistent organic pollutants (POPs). POPs are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, are capable of long-range transport, bioaccumulate in human and animal tissue, and biomagnify in food chains.
Though DDT was proposed for elimination under the 2001 Stockholm Convention of the United Nations Environmental Program (UNEP), it has continued to be used worldwide due in part to backing by the World Health Organization (WHO). In 2006, WHO issued a position statement promoting the use of indoor spray for malaria control, despite the fact that effective, least toxic mosquito control methods exist. Later, in 2009, UNEP and WHO announced a renewed international effort to combat malaria with an incremental reduction of the reliance on DDT. However, efforts to invest in real solutions are often derailed by those promoting DDT as a “silver bullet” for malaria prevention.
However, the adverse impacts to humans —including cancer, reproductive disease, neurological disease, developmental problems, and now obesity— paint a cautionary tale that long-banned pesticides continue to impact human health and the environment. While the study makes no conclusions about the risks posed to human health, Dr. Skinner commented to the LA Times that DDT advocates should take pause to consider the potential long-term impacts.
“Although the number of lives saved from malaria is significant, the long-term health and economic effects on survivors and subsequent generations also need to be considered,” the study concludes.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.