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What effects are adverse?

The WHO/IPCS has adopted a general definition for adversity which says “A change in the morphology, physiology, growth, development, reproduction or lifespan of an organism, system or (sub)population that results in an impairment of functional capacity, an impairment of the capacity to compensate for additional stress or an increase in susceptibility to other influences.”

The JRC expert advisory group agreed that adversity is an important element for the identification of an endocrine disrupter, as laid down in the report “Key scientific issues relevant to the identification and characterisation of endocrine disrupting substances [i]. At the same time the report notes in chapter 2.3 that “the point at which an observed change should be considered adverse is a topic of continuous debate.”

Endocrinologists have proposed that the ability of a chemical to interfere with hormone action is a predictor of adverse outcomes [ii]. Changes to the endocrine system in an organism following exposure to a substance should therefore always be regarded as a concern. This means that the notion of “what is adverse?” may need go beyond looking at the information that is typically available on a chemical. The measurements that are made in the internationally agreed (OECD guideline) regulatory studies that have been typically used are organ weight, lethality, number of pups born, sex ratio etc. In future, the endpoints being monitored should also include important intricate changes which can lead to adverse outcomes later in life such as lowered IQ or increased disease susceptibility.

Better tests are needed which can be used as predictors of important human diseases/disorders. For example, academic scientists have used sensitive tests such as expression of hormone receptors in the brain, expression of typical male and female behaviours, response of the prostate to hormone challenges, blood glucose after an insulin challenge, and morphogenesis of the mammary gland at puberty [iii].

Both REACH and the Pesticides Regulation require a precautionary interpretation of whether or not the effects seen are adverse, because they stipulate ‘probable serious effects’ and ‘may cause adverse effects’ respectively.

In tests to determine the harm on wildlife, only effects that affect the population level are deemed adverse. CHEM Trust considers that any effect that can reasonably be argued to potentially have some effect on the population level of wildlife species, should be considered adverse.

This page is part of CHEM Trust’s Hormone Disrupting Chemicals FAQ – Full list of questions here.

The next question is “Aren’t pharmaceuticals with EDC properties the main cause of environmental impacts, rather than industrial chemicals from consumer products?“.


[i].   JRC report: Key scientific issues relevant to the identification and characterization of endocrine disrupting substances. Report of the ED expert Advisory group. March 2013, http://ihcp.jrc.ec.europa.eu/our_activities/food-cons-prod/endocrine_disrupters/jrc-report-scientific-issues-identification-endocrine-disrupting-substances

[ii].   Zoeller et al.: Endocrine-disrupting chemicals and public health protection: a statement of principles from The Endocrine Society, Endocrinology, 153, 9, 2012, 4097-4110. doi:10.1210/en.2012-1422

[iii].  Diamanti-Kandarakis et al., Endocrine disrupting Chemicals, An Endocrine Society Scientific Statement 2009. http://www.endo-society.org/journals/scientificstatements/upload/edc_scientific_statement.pdf