12 April 2016

With ongoing public discussion of endocrine disruptors (EDs), questions are being raised about the state of the science on key issues and testing of chemicals for the assessment of potential endocrine-disrupting effects. Crop protection products are among the chemicals evaluated for such effects.

In fact, crop protection products are among the most highly tested and regulated substances in the world. They are extensively tested for potential adverse effects in humans and ecosystems in studies mandated by national governments, which include the evaluation of endocrine systems. Marketing approvals are granted only when it is proven that potential exposures will not harm humans or the environment.

Strong scientific evidence shows that crop protection products do not cause endocrine-related diseases or conditions such as cancer, diabetes or obesity. In fact, human exposure to these products is orders of magnitude lower than exposure to common, natural and more potent endocrine-active substances such as sugar, caffeine and soy protein. Independent of such substances, multiple factors account for increases in endocrine-related diseases or conditions, such as lifestyle, diet, body weight and changes in diagnostic criteria.

CropLife International issued a Policy Perspective on Endocrine Disruptors that points to well-conducted epidemiological studies examining crop protection products and human health, with most focusing on farmers and others who use these products.^{[1],[2],[3],[4]} The weight of this significant body of scientific literature does not show these products are associated with human disease, including those affecting the endocrine system.

Furthermore, existing chemical regulation, based on internationally accepted test guidelines, is designed to detect an ED. That’s because EDs produce a wide range of diverse, adverse effects that can be observed in at least one or more of the required studies. Mandatory testing for crop protection products also takes into account the potential for sensitive windows of exposure and vulnerable populations.

Moreover, these existing approaches provide protection from combined exposures to low levels of crop protection products in food or the environment. Risk assessments by regulatory authorities in the European Union and United States have consistently confirmed that low level exposure to mixtures of pesticide residues is not of concern for human health.^[5],[6],[7] Advanced methodologies for cumulative risk assessment are under development and the crop protection industry will continue to provide expert input.

The industry supports continued research to advance the scientific understanding of the way chemicals interact with the endocrine system using validated screening tools, tests and methods. It has contributed actively to the creation of test guidelines within the Organisation for Economic Co-Operation and Development and to the U.S. Endocrine Disruptor Screening Program, which is leading the development of even more sensitive tests.

Meanwhile, the weight of available scientific evidence supports maintaining current testing and risk assessment approaches related to endocrine-disrupting chemicals. The crop protection industry explains why on EndocrineScienceMatter.org. This website was created to share validated science about endocrine active substances and endocrine disruptors, especially as it relates to crop protection products.

This website discusses definitions of the endocrine system, endocrine-active substances and EDs; adverse effects; crop protection products and endocrine testing; weight of evidence approach; endocrine-related diseases and crop protection products; reference values for regulation; thresholds; low-dose effects; non-monotonic dose responses; mixture effects; and sensitive windows of exposure and vulnerable populations. These important topics are addressed here by toxicologists, ecotoxicologists and epidemiologists for the benefit of non-scientists. That’s because endocrine science matters to us all.

Howard Minigh is CEO and president of CropLife International based in Brussels, Belgium.

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^[1] Leveque-Morlais N, Tual S, Clin B, Adjemian A, Baldi I Lebailly P. 2014. The AGRIculture and CANcer (AGRICAN) cohort study: enrollment and causes of death for the 2005–2009 period. Int Arch Occ Env Hea. (2015) 88:61-73.

^[2] Koutros S, Alavanja MC, Lubin JH, Sandler DP, Hoppin JA, Lynch CF, Knott C, Blair A, Freeman LE. 2010. An update of cancer incidence in the Agricultural Health Study. J Occup Environ Med. 52(11):1098-105.

^[3] Waggoner JK, Kullman GJ, Henneberger PK, Umbach DM, Blair A, Alavanja MC, Kamel F, Lynch CF, Knott C, London SJ et al. 2011. Mortality in the Agricultural Health Study, 1993-2007. Am J Epidemiol. 173:71-83.

^[4] Frost G, T. Brown T, Harding AH. 2011. Mortality and cancer incidence among British agricultural pesticide users. Occup Med (Lond). 61(5):303-10.

^[5] European Food Safety Authority. March 2014. http://www.efsa.europa.eu/en/press/news/150312.htm.

^[6] U.S. Department of Agriculture. 2013. http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=stelprdc5098551.

^[7] United States Environmental Protection Agency. 2001. Cumulative risk assessment: Developing the methods available, papers and where they may be located. June 21, 2001. http://www.epa.gov/pesticides/cumulative/Cum_Risk_AssessmentDTM.htm.