Troubled waters: A new call for conducting low-dose and mixture toxicity testing

While the cocktail of chemicals we are exposed to is growing every year, our regulatory and research institutions do not adequately consider synergistic combinations of chemicals mixtures. New research to be published in the December issue of Environmental Pollution examines the behavior-related endpoints (swimming and eating behavior) of aquatic amphipods following exposure to the fungicide prochloraz and the antidepressant fluoxetine. Simulating a real-life aquatic environment, researchers found both chemicals may cause significant sublethal effects at low concentrations, as well as some chemical interaction that could modify their toxic effects.

According to one of the authors of the report, Alex Ford, of Portsmouth’s Institute of Marine Biology, “Most of the world’s urban waterways receive a cocktail of pollutants from agricultural run-off to human sewage containing sometimes high concentrations of medicines like antidepressants. Such cocktails may stop short of killing marine species, but we are concerned at what sub-lethal effects certain pollutants may be having. These findings underline the importance of understanding and knowing the impact of complex mixtures of pollutants are having. One of the great conundrums for environmental toxicologists is how can we possibly determine or predict the effects of every combination of chemicals when there are thousands released into the environment, many of which have had quite limited toxicity assessment…. The way an animal feeds and moves is a sensitive way of detecting the sub-lethal impact on individual organisms which are likely to be relevant elsewhere in the food chain and through our entire ecosystem."

[Source: Science Daily]