There are huge gaps in what experts know about how complex mixtures of pollutants disrupt hormones, growth and reproduction in wildlife, scientists reveal today.
A paper out today answers the Government Office for Science’s call for an independent review on what scientists know and don’t know about what hormone-disrupting chemicals do to wildlife.
Treated water contains endocrine-disrupting chemicals (EDCs) such as oestrogen from the contraceptive pill, metformin, which controls blood sugar in Type 2 diabetes, and fluoxetine in anti-depressants.
The glaring lack of evidence about the effects of hormone-altering chemicals is laid bare amid growing amounts in rivers, oceans and sea-life such as killer whales, dolphins and tuna.
“We are a very long way from understanding based on a chemical’s structure alone if it will cause adverse effects in the environment, on what species and at what concentration,” said Brunel ecotoxicologist Professor John Sumpter. “We usually notice these effects after they occur and that’s not the position we want society to be in. We want to be able to predict toxicity.”
EDCs upset basic biology such as growth, reproduction and how organs work. They come from plastics and electronic waste such as old mobile phones and also PCBs (polychlorinated biphenyls) and flame-retardants that end up in landfill. One chemical in the contraceptive pill can feminise male fish, Prof Sumpter highlights. “You find eggs in their gonads as well as sperm.”
Highly toxic and long-lasting, PCBs were banned globally in 2004. Killer whales in North West Scotland with high PCB exposure have had no calves for 25 years. Globally up to 50% face extinction in the next 100 years because of high PCB levels, scientists predict.
“The potential threat to wildlife from PCBs became widely accepted in the 1960s-1980s and since we’ve seen national or international bans on some,” said Dr Paul Jepson, European Veterinary Specialist in Wildlife Population Health at ZSL’s (Zoological Society of London) Institute of Zoology. “However, in most cases when an EDC has caused adverse effects on wildlife the connection has only been established after the population had declined.”
Despite the high amounts of EDCs in the environment, most research looks at the effect of just one EDC on one species or environment, says the study, led by Professor Sir Charles Godfray from Oxford Martin School at the University of Oxford. But there are few facts about how EDCs interact with each other and other pollutants.
“Increased plastic consumption, the rise in anti-depressant use, Type 2 diabetes and EDCs from melting Arctic ice will all increase the presence of EDCs,” Prof Sumpter added. “Yet, substantial uncertainty exists about the potential negative environmental impacts.
“Policy-makers need to balance the known risks outlined in this restatement and the known unknowns identified with the economic, health and other benefits of each substance.”
Hayley Jarvis, Media Relations
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