School of Biological Sciences
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School of Biological Sciences |
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Environmental Pollution and Toxicology |
During the last decade or so, concern has mounted that Endocrine disruption could turn out to be a major global environmental problem such as that posed by Global Warming. These fears have been exacerbated by the connections with lowered sperm counts in human males, putative involvement by PCBs and other organochlorines involved in planetary wide transport from warm to cold climate zones. After a period of poor understanding, new evidence is beginning to shape opinions:
The evidence for chemicals having harmful effects on the human endocrine system is "weak", according to the first world-wide survey of research in the field. The survey was carried out by the UN International programme on chemical safety (IPCS) and has now been posted on the web. Its aim is to evaluate the threat posed by endocrine disrupting chemicals (EDCs) by applying a "collective weight of evidence" method to state-of-the-art scientific findings.
A key conclusion is that signs of damage to humans from hormone-mimicking substances are only "inconclusive and inconsistent", with "weak evidence that human health has been adversely affected by exposure to endocrine-active chemicals".
The conclusions could influence the EU's strategy on endocrine disrupting chemicals (EDCs). Case studies focus on two potential adverse impacts that have brought EDCs to the top of the EU regulatory agenda. For the first, declining sperm counts , there are "no human data" to support an EDC effect. For the second, endometriosis, the data are "equivocal".
A spokesperson for EU chemical industry association Cefic welcomed the report as a cool look at the evidence that should take the heat out of the EU debate. "There is actually, when you look at the weight of evidence, not a causal relationship for many of the chemicals claimed to act as endocrine disrupters," said EDC specialist Rob Taalman.
But the report says its overall conclusion on human effects is "not meant to downplay the potential effects of EDCs" and instead "highlights the need for rigorous studies". Serious endocrine-disrupting effects remain "biologically plausible" and little is known about the consequences of low-level chronic exposure to EDCs. Moreover, effects on wildlife are "extensive".
The EU strategy has so far produced little more than a list of 12 chemicals for priority assessment of endocrine effects. It is understood that a number of consultancy reports recommending next steps for action on these will be presented to the Commission's environment directorate in early 2003 with a larger list of potential EDCs later in the summer.
IPCS Global Assessment (see Exec Summary (International
Programme on Chemical Safety (supported by WHO & UNEP)
http://www.who.int/ipcs/publications/new_issues/endocrine_disruptors/en/