Exposure to organochlorine chemicals, such as DDE and PCBs, is linked to increased rates of sperm abnormalities that may lead to fertility problems, according to a new study published in the journal Environmental Health Perspectives. This is the latest study in a long line of research implicating endocrine (hormone)-disrupting chemicals in reproductive diseases.
Researchers investigated this issue by observing the blood serum and sperm quality of 90 men, aged 22-44, participating in health studies in the Faroe Islands, an archipelago under Denmark’s control that is located between Iceland, the UK and Norway. Faroe islanders consume a high seafood diet that often consists of pilot whale, integral historically as a food source for the Faroese people. However, this practice exposes the Faroese to higher than average levels of environmental contaminants. For the study, data on umbilical cord blood and blood serum at age 14 was available for 40 of the participants, allowing a researchers to measure lifetime impacts.
Faroese participants were screened for sperm aneuploidy, a condition which usually involves an abnormal number of X or Y chromosomes in sperm, and is suspected as contributing to congenital abnormalities and up to 50% of early pregnancy losses. Results found that adult concentrations of DDE and PCBs in participants was associated with increased rates of aneuploidy. Concentrations of the organochlorine chemicals at age 14 were significantly correlated with increased rates of aneuploidy at adult age, however the link between concentrations in umbilical cord blood and adult aneuploidy was not significant.
“Exposure to these chemicals in adolescence may lead to reproductive problems years later,” said Melissa Perry, ScD, MHS, chair of the Environmental and Occupational Health program at George Washington University and lead author of the study in a press release.
DDE (dichlorodiphenyldicholorethylene) is the breakdown chemical of DDT (dichlorodiphenyltrichloroethane), 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 DDE have remained alarmingly high in many locations, including surface waters, the Arctic, and even some U.S. towns and national parks. DDT, DDE, PCBs and other persistent organic pollutants (POPs) are known to resist environmental degradation through chemical, biological, and photolytic processes.
“DDT and other pesticides like it continue to linger in our environment and contaminate our food,” said Dr. Perry to NY Daily News. A study published in 2015 found that long banned but persistent pesticides like DDT may reemerge as a result of soil erosion in agricultural fields. However, a large source of exposure to these chemicals is through eating meat. This is because many POPs are also known to bioaccumulate and biomagnify, increasing in concentration as they move up the food chain from prey to predator. “Most people can reduce their exposure to PCBs and DDT by cutting back on foods that are high in animal fats and choosing fish wisely,” said Dr. Perry in a press release.
DDT and DDE have been linked to a number of reproductive and endocrine diseases. A 2013 study found that exposure to DDT and a range of other pesticides was linked to decreased sperm quality. A two-part French study published in 2014 found that sperm quality in French men had decreased 30% over the past 16 years as a likely result of chemical exposure, with the implication that these similar results would be seen in other areas of the world. Research shows women have also been impacted by exposure to POPs. A study published early this year found that exposure to POPs is associated with an earlier start to menopause. Another study published in June found that in utero exposure to DDT was directly linked to breast cancer later in life. Lastly, DDT has been shown to cause adverse impacts that span generations. A study published in 2013 by Michael Skinner, PhD, found that exposure to DDT contributed to obesity three generations down the line.
The results of this and numerous other studies confirm that relying on the same risk-based approach to regulating toxic chemicals that allowed the widespread use of DDT and other POPs is simply unacceptable. “This study, and others like it, suggest that any decisions about putting biologically active chemicals into the environment must be made very carefully as there can be unanticipated consequences down the road,” said Dr. Perry. Beyond Pesticides urges regulators at the U.S. Environmental Protection Agency (EPA) to strongly consider the data and conclusions developed by independent scientists. As EPA continues to allow pesticides to market that pose unacceptable risks to the environment given widely available organic and natural alternatives, local residents must stand up in opposition, and start at the community level to get unnecessary toxins out of their environment.
To read more about an alternative approach to regulating toxic pesticides, and to see more studies linking pesticide exposure to common diseases, see Beyond Pesticides’ Pesticide Induced Diseases Database.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.