5. What are potential sources of EDC exposure?
Lack of scientifically sound data about the frequency, length and levels of exposure to endocrine disrupting chemicals (EDCs) is the weak link in the argument that they have harmful effects on human and animal health. Most of the information on EDC exposure has focused on the presence of persistent organic pollutants, such as PCBs, dioxins, DDT and other chlorine-containing pesticides, in Europe and North America. Exposures to other non-persistent EDCs have not been investigated in any depth.
Another shortcoming is the lack of information on exposure during critical periods of human or animal development. Moreover, the available information relates mostly to EDCs present in the environment – such as in the air, food and water – rather than to levels in blood and tissues in the body. Limited exceptions are human breast milk and fat tissue samples, which have been screened for potential EDCs, such as organochlorines.
Generally, exposure to potential EDCs occurs through contaminated food and groundwater, gas emissions from industrial sources and the burning of waste, and contaminants in consumer products.
Despite a heavy investment of money, time and effort worldwide, information comparing human and wildlife EDC exposures in different countries is still sorely needed. Such information, obtained through field studies on wildlife and studies in human populations - epidemiological studies - on diseases or other observations like sperm quality or outcomes of pregnancy, is essential to establish causal relationships between exposure and response. Exposure information is also essential to produce a credible risk assessment of this problem. More...