Exposure to endocrine-disrupting chemicals – Back in the news
Tuesday, 21 May 2013 at 1:25:PM
A report published in February, entitled State of the science of endocrine disrupting chemicals - 2012, (along with the corresponding press release) adds additional weight to the argument for more caution in the use of endocrine-disrupting chemicals (EDCs) such as phthalates and bisphenol A.
The report, and published jointly by the United Nations Environment Programme (UNEP) and the World Health Organization (WHO), says that EDCs are “a global threat that needs to be resolved”.
At the same time, the report says that much more research is needed. The authors make the quite pointed remark that to obtain a clear picture of the extent to which EDCs affect the health of humans and ecosystems in general “it is critical to move beyond the piecemeal, one-chemical-at-a-time, one-disease-at-a-time, one-dose approach currently used by scientists.”
EDCs, defined as chemicals known or suspected to be capable of interfering with hormone receptors, number about 800, and include well-known constituents of everyday objects such as phthalate esters used as plasticisers, flame retardants in furnishings, and bisphenol A in tinned goods (see this article, "No easy fix for food can coatings", for an overview of alternatives to bisphenol A in food cans).
The presence of these chemicals alone is enough to raise concerns in some quarters, but the call for action becomes unignorable when when considered alongside the rising incidence of endocrine-related disorders. These disorders can manifest themselves in a variety of ways, including cancer, obesity, type 2 diabetes, low semen quality and genital malformations. Such serious effects can lead to somewhat alarmist headlines in the popular media, exemplified by this article in the Daily Mail following the release of the UNEP/WHO report.
Despite this level of concern, action on regulating the use of EDCs has been slow in coming. This is essentially because concrete evidence of cause and effect is exceptionally hard to come by in any real-life situation amenable to experimental analysis.
The resulting piecemeal process of evidence-gathering, although criticised in the UNEP/WHO report, is unlikely to be superseded any time soon. Further complications arise from disagreements between researchers over issues of experimental design, as illustrated by this journal article on phthalates used in PVC flooring, a subsequent letter to the editor and the response from the authors.
Even with improvements in experimental methods, the big question ‘Are EDCs definitely harmful to humans?’ is only ever likely to be answered incrementally. Until then, a precautionary approach is the only reasonable way forward, and this should involve restricting the use of the chemicals most strongly suspected to be hazardous to health.
Importantly, too, there should be no let-up in research into the precise hazards posed by EDCs. As spelt out by the WHO’s Director for Public Health and the Environment, Dr Maria Neira, “We urgently need more research to obtain a fuller picture of the health and environment impacts of endocrine disruptors”.
So what’s the message for the GC/MS analyst from all this? The answer lies in the main recommendations outlined in the current report. These boil down to the need to carry out more biological testing, to assess the actual amount of chemicals in the body. The other aspect is material emissions testing, to fill in gaps in knowledge of the chemicals actually present in products and materials.
Both of these fields of study present challenges for the analyst. As anyone who’s ever dealt with GC/MS analysis of breath or consumer goods will know, the effort involved in confirming without doubt the presence (or absence) of every target compound in such complex samples can be considerable. Fortunately, however, GC/MS technology continues to improve, with new sampling devices and thermal desorption instrumentation making analyses ever more quicker, reliable, and comprehensive.
It’s therefore up to researchers to demand the very best from the equipment that they use. This will enable them to carry out the essential groundwork needed to inform future medical studies and ultimately provide clear answers to the complex health issues raised by EDCs.
David Barden received his Ph.D. in Organic Chemistry from Cambridge University in 2004, and during his time as an editor at the RSC wrote news pieces for Chemistry World on various scientific topics. He is now Technical Copywriter at Markes International, where he draws on the expertise of his colleagues to explain how new thermal desorption and mass spectrometry technologies can be applied to analyse volatile organic compounds in a wide variety of situations.