Monday, September 12, 2011

Drought changes toxicity of aquatic pollutants

Environmental Research Web: Some areas of the southern US are suffering from the longest dry spell since 1887. That could prove problematic for aquatic organisms, according to a study from Baylor University.

The research found that drought conditions make some chemicals in the environment more toxic to fish and other aquatic life. Specifically, drought conditions were found to exacerbate the magnitudes of natural pH shifts in the water. This is important, the researchers say, because the toxicity to aquatic life of some contaminants, such as ammonia, depends on the pH level.

Also, more than 75% of the essential drugs described by the World Health Organization and approximately one-third of modern pesticides have ionizable groups of compounds. These "weak base" compounds can become more toxic to fish when dispersed in the environment if surface pH levels are high.

..."The importance of this work is it shows that we may be underestimating or overestimating the adverse effects of some chemicals on fish," says study co-author Bryan Brooks of Baylor University. "How drought conditions, especially those influenced by climatic changes, impact fluctuations of the water's pH level is just now emerging as an area of concern in regards to making certain chemicals more toxic and more likely to accumulate in fish."…

The Glade Creek Grist Mill, a West Virginia attraction in Babcock State Park, shot by Gabor Eszes (UED77), Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

No comments: