A new study by the U.N. Environment Program and the World Health Organization finds many synthetic chemicals affect the hormone system and could have significant health implications. The joint study updates scientific evidence presented 10 years ago and identifies the effects of human exposure to so-called hormone-disrupting chemicals.
Human health depends on a well-functioning endocrine or glandular system to regulate the release of certain hormones that are essential for some functions. They regulate metabolism, growth and development, sleep and mood.
Some substances known as endocrine disrupters can alter the functions of this hormonal system increasing the risk of adverse health effects. Maria Neira, World Health director of public health and environment, said there is growing evidence that some endocrinal disrupting disorders or diseases are on the rise.
“The speed to which these diseases are increasing cannot exclusively be justified by genetic problems,” said Dr. Neira. “It has to be as well be associated with environmental factors, issues like nutrition or bad nutrition or age or other factors that I would say are external and probably combined.”
Endocrine disrupting chemicals are found in many household and industrial products. They can enter the environment mainly through industrial and urban discharges, agricultural run-off and the burning and release of waste.
Human exposure to these chemicals can create a lower sperm count in young men and contribute to breast cancer in women. Ms. Neira says prostate cancer risks are higher among those men exposed to pesticides, particularly in those countries where occupational health is not well developed.
“We have an association as well with adverse effects on the developing nervous system in children and those can include a negative impact on brain development, and we have seen an excess risk of thyroid cancer among those workers who are using pesticides,” said Ms. Neira.
The report also raises concerns on the impact of endocrine disrupting chemicals on wildlife. For example, it notes exposure to such chemicals in the U.S. State of Alaska may contribute to reproductive defects, infertility and antler malformation in some deer populations.
It says the decline in population species of otters and sea lions may also be partially due to their exposure to PCBs, the insecticide DDT, and other persistent organic pollutants and metals, such as mercury.
Among its recommendations, the study urges more comprehensive testing to identify other possible endocrine disrupters, their sources, and routes of exposure. It notes what is known about these chemicals is just the tip of the iceberg.