Researchers at Cary Institute for Ecosystem Studies found alarming levels of pharmaceutical compounds in the skis. Of the 69 compounds, some are found in concentrations that endanger the animals feeding on them, such as trout and platypus. Moreover, stream insects can pass drugs along with spiders, birds and other predators when they appear as adult flying.
Pharmaceutical contamination is present in surface waters around the world. Most wastewater treatment plants are not equipped to remove the drug from sewerage, and aging of septic tanks and pipes contributes to the problem.
Co-author of the study Emma Rosi is a water ecologist at Cary Institute.
"Stream of life swims in a mix of drugs. Our study is the first to show that this chronic drug contamination can concentrate on water insects and move food on the net, in some cases by exposing topical predates to therapeutically relevant doses," Rosi explained.
The study focused on six streams in Melbourne, Australia, where researchers searched 98 pharmaceutical compounds including common drugs such as antibiotics, antidepressants, antihistamines, and NSAIDs. The team collected aquatic insects and mountain spiders for testing.
Author of the study Erinn Richmond is a freshwater ecologist at Monash University in Australia. "We have focused on the prudent spiders because they build their networks through flowing and food for adult insects that leave water," said Richmond.
Tissue analysis revealed up to 69 different pharmaceutical compounds in water insects and up to 66 compounds in mountain spiders. Most drug concentrations had insects collected downstream from wastewater treatment facilities or in heavily populated areas with potential leakage of septic tanks. Across these sites, pharmaceutical concentrations were on average 10 to 100 times higher in comparison to sites with less contamination.
Coauthor of Studies Jerker Fick is a chemist in University of Umeå in Sweden that analyzed insect and spider samples.
"The insect tissue contained drug concentrations more than the concentrations measured in surface waters," Fick said. "We also found a variety of drug spiders, suggesting that drugs go from the water to the prey of predators, by which other animals are exposed to drugs on food."
Richmond added: "Drugs were present in every insect and spider we tested – including those collected in the Dandenong Ranges National Park. Even this seemingly untouched location was contaminated, probably because people live in the park's drainage area and visit the park . "
The study was published in the journal Nature of communication.
Per Chrissy Sexton. Earth.com Staff Writers
Photo Credit: Denise Illing