Proposals to ban chemicals that could cause birth defects and reproductive damage to animals may be based on inadequate science, a British professor will tell members of the European Parliament on Tuesday.
Peter Calow, professor of biological sciences at the University of Sheffield, will tell the Brussels meeting that research on endocrine disruptors, chemicals that have been blamed for reproductive system damage in humans and animals, has been focused on the wrong targets.
He said: "The work that has been done so far has been based in the laboratory and has looked at chemicals at high concentrations over short periods. The emphasis has been on the effects on individual animals.
"When you are dealing with chemicals affecting humans, you have to worry if even one develops a birth defect. But with animals the issue is whether the effect is enough to damage a whole population over time. For that you need to look at lower concentrations of chemicals over long periods and look at ecology and populations, not individuals."
Professor Calow said that although there were potential ill-effects, most might not be realised in actual ecological systems.
He added that there were clear cases in which endocrine disruptor chemicals caused serious ecological damage. The clearest was tributyl tin, used to discourage marine organisms from growing on ships' hulls. "The effect was clearly seen because female snails grew penises and became infertile. This affected population density and the whole ecosystem. But if you ban the chemical, which is now happening, you find that a replacement comes along that you know less about."
Professor Calow will also tell the MEPs that more research is needed to find out whether industry is to blame for all the endocrine effects seen by ecologists. "It used to be thought that industrial waste was responsible for some of these effects seen downstream of sewage works," he said. "But it may turn out that the chemicals are produced naturally by humans or are waste from the contraceptive pill."
Professor Calow studies how endocrine disruptor chemicals affect water fleas, snails and worms. He will call for the European Commission, already a major funder of this work, to spend more.