(Beyond Pesticides, June 19, 2015) A new study directly links exposure to dichlorodiphenyltrichloroethane (DDT) in utero to the development of breast cancer later in life. Published in the Journal of Clinical Endocrinology and Metabolism, the study looked at data that were taken from a California program that evaluated samples from women during 1960s, when DDT use was popular. DDT is known to be an endocrine disruptor, and is linked to serious health effects. Although DDT has been banned for many years, residues still linger in certain areas of the U.S. and continue to cause environmental and health hazards.
The recent study, titled DDT Exposure in Utero and Breast Cancer, focuses on 118 mothers who were members of Kaiser Foundation Health Plan from 1959-1967 and had daughters that were diagnosed with breast cancer by their 50s. Stored blood samples from these mothers gave researchers an idea of how much DDT they were exposed to during pregnancy or soon after giving birth. They found that elevated levels of DDT in the mother’s blood led to a four-fold increase in the daughter’s risk of developing breast cancer. Among those with cancer, 83% had a form of cancer called estrogen positive breast cancer, which is caused by the estrogen hormone malfunctioning to promote tumor growth. Women with the highest rate of exposure to DDT in utero were found to have a more advanced type of breast cancer than women who were not exposed to DDT in utero.
DDT is an organochlorine pesticide that was banned in the U.S. in 1972, following a massive environmental movement spurred by Rachel Carson’s Silent Spring, which documents the adverse environmental effects resulting from the indiscriminate use of pesticides. DDT was widely used to control mosquitoes for malaria abatement, and in agriculture. Despite the fact that DDT was banned in the U.S. 43 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. This is because DDT/DDE are persistent organic pollutants (POPs), which 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.
DDT/DDE has affected human health and the environment in many ways. DDE has been linked to an early start to menopause and potentially harmful effects on ovarian function. People with high levels of exposure to DDT are also four times more likely to have Alzheimer’s disease than people with low levels. A 2014 study showed that exposure to DDT in utero cultivates conditions that increase an individual’s likelihood of becoming obese and developing type-2 diabetes, while another study documented generational effects associated with DDT exposure, finding that the third generation of pregnant rats injected with DDT exhibited dramatically higher levels of fat and weight gain despite not being directly exposed to the pesticide themselves.
As mentioned earlier, DDT is extremely persistent, affecting humans and wildlife to this day. A community in central Michigan continues to deal with the fallout of a pesticide company that produced DDT nearly half a century ago, leading to mass bird die-offs from exposure to the deadly insecticide. In the San Francisco Bay canal, DDT is still poisoning fish and posing a threat to human health, despite numerous cleanup attempts after contamination was discovered over 50 years ago. DDT can move through the environment, contaminating wildlife even in places where it has likely never been used. Researchers suspect that DDT is carried through atmospheric currents, where it is deposited during rain events as moisture condenses over cold regions ””at high altitudes and latitudes.
The Environmental Protection Agency (EPA) has notoriously been slow to act against the use of dangerous pesticides. Although DDT has been banned, its effects live on. Other dangerous chemicals continue to be used with vigor, similar to the use of DDT years ago. U.S. regulators continue to drag their feet in moving forward with the statutorily-mandated review of pesticides for the previously unevaluated risk of potential endocrine disruption. Yet, findings like the current study and many others highlight the importance of generating strong pesticide regulations that take into consideration endocrine-disrupting effects when evaluating safety standards for worker protection and human health impact.
Another class of insecticides in particular, neonicotinoids (neonics), have been implicated in environmental degradation and important pollinator declines. In Canada, Ontario’s Environmental Commissioner has even named neonics to be a “bigger threat” to the environment than DDT, and created new rules to limit their use. Here in the U.S., Beyond Pesticides, Center for Food Safety, Pesticide Action Network North America, and beekeepers filed a lawsuit against EPA in 2013 calling for a ban on clothianidin and thiamethoxam, which are two neonicotinoids used extensively on corn, soybean and canola seeds.
Join Beyond Pesticides in supporting beekeepers across North America in their fight against neonicotinoids and learn the many ways you can BEE Protective by visiting our website! We also urge consumers to support organic agriculture as a method of avoiding exposure to endocrine disrupters, neonics, and all other dangerous pesticides.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.