« Recent reports have raised questions about the possible effects of some chemicals on the human endocrine system.
Some natural and man-made chemicals can and do interact with the endocrine system, or are “endocrine-active.” In some cases, this interaction is harmless – the substances lack sufficient potency, or exposures are so low that no effects occur at all; in other cases, the body naturally adjusts, and the exposure causes no health effect.
However, some substances under certain exposure scenarios go beyond a simple interaction and can result in adverse health effects – these substances are referred to as “endocrine disruptors”.
Through governmental, academic and industry efforts, considerable progress has been made to develop methods, tests and data to help answer questions about whether and how certain chemicals may affect the endocrine system. However, some recent studies have failed to incorporate critical information including exposure and weight-of-evidence analysis or have used unreliable methods, reducing their relevance to sound decision making.
More research is needed to better understand whether, how and to what effect specific chemicals interact with the endocrine system.
By improving screening and testing, regulatory agencies can make decisions based on scientific evidence as they develop and implement programmes intended to reduce risks associated with endocrine disrupting chemicals (EDCs).
The American Chemistry Council (ACC) recently released 11 “Principles for Identifying Endocrine-Active and Endocrine Disrupting Chemicals”, a set of recommendations to promote reliability, consistency and scientific integrity in the screening and testing of chemicals for endocrine activity and endocrine disruption.
These principles are industry’s latest contribution to advancing scientific understanding of endocrine-active and endocrine disrupting chemicals. Industry’s Long Range Research Initiative also has developed cutting-edge screens and tests to support these efforts and has made substantial contributions to development of high-throughput tools that can help prioritise and screen chemicals at a much faster pace than traditional methods.
Chemical manufacturers also have participated in the US EPA’s Endocrine Disruptor Screening Programme and have submitted data and analysis on test-method development and chemicals, for use by regulators to determine whether they activate the endocrine system and, if so, whether they cause adverse health effects due to that interaction.
Chemistry is fundamental to human life; everything is made of chemicals, including the human body and all of nature. Chemical manufacturers take seriously their responsibility to produce chemistries that enable important product performance benefits and that can be used safely, and they undertake extensive scientific analyses to evaluate potential risk of their chemicals, from development through use and safe disposal.
Box: Summary of the 11 principles
1. Apply precise and accurate characterisations to chemicals: Chemicals should not be labelled as endocrine disruptors unless there is scientific consensus that they cause adverse health effects through an endocrine mediated pathway. This will prevent confusion and potential unnecessary market disruption.
2. Adhere to credible testing methods and data: Programmes should incorporate objective measures of data quality and follow Organization for Economic Cooperation and Development (OECD) guidelines for good laboratory practices.
3. Conduct thorough investigation: Screens and tests should examine hormone-related effects, characterise systemic toxicity and consider biological factors such as absorption, distribution, metabolism and excretion.
4. Mutual acceptance of data: Data from tests, conducted according to OECD guidelines, should be acceptable for use by multiple organisations so duplicative testing can be minimised.
5. Engage in transparent decision making: Testing programmes should engage in clear, public and consistent decision-making processes.
6. Be effective and efficient: Testing programmes should be designed to maximise efficiency and minimise delays.
7. Apply advanced technology: Programmes should utilise validated, new technologies to increase progress and reduce the need for animal testing.
8. Consider real world exposures: Testing programmes must incorporate relevant exposure information so conclusions are based on actual risk, not solely on hazard.
9. Incorporate weight-of-evidence analysis: All credible evidence should be incorporated to ensure that the most reliable and relevant studies carry the greatest influence on conclusions and outliers do not skew findings.
10. Embrace a proactive approach: Screens and tests should be highly sensitive and as accurate as possible. Screens should err on the side of over-identification, and in cases where results are ambiguous, further testing should be pursued.
11. Accept safe levels of exposure: Thorough examination can identify safe exposure levels. The hypothesis that low levels of exposure can cause harmful effects that are not adequately captured by traditional toxicological studies is often discussed, but rigorous reviews by scientists at regulatory agencies have been unable to validate the hypothesis, so changes to current testing and safety assessment approaches are not warranted. »
Article of Dr Sue Marty, PhD, ICCA representative on Unep Advisory Group on Endocrine Disrupting Chemicals; Dr Marty is also toxicology and environmental research and consulting science leader at The Dow Chemical Company.
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