Humans are exposed to thousands of chemicals in a life-time via air, food and water. A significant number of these chemicals are able to disrupt the endocrine system and are known as endocrine disrupting chemicals (EDCs). The list of chemicals with EDC activity has increased considerably over the last decade. Evidence indicates that these chemicals can compromise the reproductive system, thyroid signalling mechanisms, this includes tissues and organs associated with energy metabolism, glucose control, fat cell development and satiety. It is possible that all endocrine systems are affected to some degree by environmental chemical exposures. EDCs activate the same receptors and signalling pathways as hormones and act at low concentrations and they are subject to the same biological regulatory systems as hormones. As they control all aspects of physiology the same can be expected from EDCs.
The idea that EDCs are impacting significantly on human health is of great concern. More information is needed to expand the list of organs and tissues affected and more research is needed to identify and classify the diseases they are causing in humans and animal models. Currently there is sufficient data to identify EDCs as a public health problem that must be addressed.
EDCs are ubiquitous and will ultimately land up in the aquatic environment which serves as a kitchen sink. Therefore the effect of mixtures should be investigated especially as many of the chemicals are present at low levels. Similar individual chemicals are combined at concentrations below the detection limits may result in an additive effect which can then be measured in in vitro bioassays. There are a number of bioassays available to measure estrogenic and androgenic activity.
Current South African legislation does not require that chemicals be screened for endocrine disruptive effects before being used in food, cosmetics, household, industrial, agricultural, pharmaceutical products and packaging materials. Industrial effluents, sewage treatment works and landfill sites all contribute to the pollution of our water sources and environment.
Research strategies are needed to address the link between sources, exposure and the associated health effects of EDCs. The EDC and Toxicology laboratory at the University of Pretoria with the collaborators and organisations has the expertise to investigate these issues and also to train students to a high level of expertise in the field.