What are Endocrine Disrupting Chemicals?

Endocrine Disrupting Chemicals (EDCs) are biologically active chemicals of a diverse origin and uses (industrial chemicals, plastic components, components of cosmetics, pharmaceuticals, pesticides, biocides etc) that interfere with the hormonal system of animal species, including humans, leading to poor health and the development of disease. They are also called "hormone disruptors".

The hormonal system can be seen as a network of chemical messengers (hormones) that circulate across the body and transfer the necessary "information" to specific organs to regulate their function and development. These continuous coordinated interactions have the key role to maintain our bodies in equilibrium.
During the development of a male foetus, for example, hormones released from the brain stimulate the production of the male hormone testosterone, which passes information to the reproductive system in order to initiate the development of male reproductive organs, together with other male characteristics. When too much testosterone is produced, the brain ceases stimulating its production and testosterone levels are reduced.
Very small amounts of EDCs are capable to interfere with or "disrupt" the natural action of hormones, pass the wrong "messages" to specific organs and result in alterations in morphology, physiology, growth, reproduction, development and behaviour. Such changes have been linked to endocrine-related disorders such as reproductive failure, reproductive organ deformities and cancer, diminished fertility, altered sex differentiation, metabolic disorders (e.g. obesity and diabetes in mammals), immune dysfunction and cognitive impairment among other effects.

Why EDCs are different from other toxic chemicals?

What makes these chemicals particular is that they mimic/disrupt the role of hormones that are naturally present in very small concentrations. Thus, a very tiny amount of an EDC is sufficient to trigger an effect. When the wrong hormonal signals are sent during the early-life stages of development, a whole erroneous cascade of events is triggered and the "wrong programming" is set, which will inevitably result in disease and dysfunction later in life. This means that unborn babies (exposed through their mothers), infants and children, are the most vulnerable to EDCs exposure.

When juveniles and adults are exposed to small amounts of EDCs effects may be different because the biological system of the adults can compensate small alterations without resulting in disease. In the classical risk assessment of toxic chemicals the tests are done mainly in adults and therefore they fail to detect the effects of small doses of EDCs in juveniles. Furthermore, these tests assume a safety level, below which exposure can be considered safe. However, scientists are warning us that for EDCs there is no safe level exposure during the early-life stages of development and growth. All these observations, together with the fact that currently there are very few tests in the assessment of toxic chemicals that detect endocrine disruption specifically, point out that several EDCs are being erroneously classified as safe.

The State-of-the-Science for EDCs

There are still great uncertainties regarding the diseases triggered by these chemicals and what are exactly the first biochemical reactions in this long cascade of events that lead to disease. In laboratory studies, scientists have proven that exposure to EDCs during early-life leads to endocrine-related diseases and although several suggestions have been given on how this occurs, in many cases the exact mode of action is an ongoing investigation. For example, one of the most cases of endocrine disruption in wildlife is the development of "imposex" in marine snails, a "masculizination" condition where female snails develop a penis that blocks their reproduction following exposure to the paint biocide agent Tributyltin (TBT). TBT-paints were used widely until the 80s on the hulls of the boats to avoid the attachment of marine organisms that reduce the speed of the boat and cause metal corrosion. A tiny drop of TBT in twenty 50x25 meters swimming pools is enough to cause "imposex" (!!) but why this phenomenon occurs is a more than 40-years ongoing investigation. TBT was finally totally banned in 2008 due to the continuous evidence of the adverse impacts on aquatic life.
In such circumstances, where dangers to human, wildlife and environmental health have been detected but scientific data is insufficient to permit the full evaluation of the risk and employ safety measures, EU has to apply the "precautionary principle" and regulate the production and distribution of, in this case, EDCs to avoid further potential damage.

EDCs enter the European Regulations and create a "political disruption".

Due to their extraordinary effects, EDCs have been in the agenda of the European Union since 1999, when the 'Community strategy for endocrine disruptors' (COM(1999)706) was adopted, foreseeing more research on EDCs to understand their action, identify them and gradually remove them from Europe's market. Step by step EDCs were incorporated in the legislations related to chemicals (Regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals-REACH; Water Framework Directive-WFD; Medical Devices; Cosmetics) but it was the Plant Protection Products Regulation EC 1107/2009 (PPPR), put into force in 2011 to regulate pesticides, the first legislation to apply the precautionary principle on EDCs and introduce "hazard-based cut-off" criteria, as it is applied for carcinogenic and toxic to reproduction compounds i.e. any pesticide with EDCs properties is regarded as a hazard and must be banned (hence the wording "cut-off"). Since pesticide residues are found in our food, deciding against the use of such pesticides was certainly a wise move. EDCs "cut-off" criteria were also incorporated later in the Biocide Product Regulation EU 528/2012 (BPR), which entered into force in 2013.
Ironically the Pesticide and Biocide Regulations entered into force before defining the criteria to identify EDCs. This made the criteria a target for the industry and industry-friendly institutions in the EU that profit from pesticide use in agriculture and intensive farming, using all kind of tactics to create doubt on the adverse effects that these chemicals cause and on what is an EDC overall.

PAN Europe is following closely the process of the selection of the criteria to identify EDCs with the aim to help the Commission select the correct criteria, based on the state-of-the-science on EDCs, that will succeed to protect human health, our future generations and the environment from exposure to these chemicals.

Check out our Assessment of endocrine disrupting pesticides, our timeline on the downfall of the Endocrine Disruptors Policy and PAN-Europe's position on the roadmap published by the Commission to outline the current developments on EDCs.