Insects that live near streams are poisoned by cocktail medications and medications including antibiotics and antidepressants. This shows new research.
The dangerous chemicals are passed through the food chain when the contaminated insects are eaten by predators such as trout and platypus.
Many of the insects studied contained pharmaceutical chemicals in concentrations that could endanger the lives of the animals that feed on them.
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Insects that live near streams are poisoned by cocktail medications and medications including antibiotics and antidepressants. These chemicals are passed on to predators, including the neighboring spider (photo photo)
The co-author of the study, dr. Emma Rosi, an expert at the Cary Institute of Ecosystem Studies in the United States, said: "The life of the river is floating in a mix of pharmaceuticals.
"Our study is the first to show that chronic drug contamination can be concentrated in aquatic insects and can move food webs up, sometimes exposing top predators to therapeutically relevant doses."
An international team of researchers has investigated six streams for 98 active pharmaceutical ingredients in Melbourne, Australia.
They measure for common medicines like antibiotics, antidepressants, antihistamines and NSAIDs.
Up to 69 pharmaceutical compounds were found in aquatic insects and 66 in trailers building their lanes from streams collected by the team.
Drug concentrations were highest in insects collected downstream from wastewater treatment plants or in densely populated areas.
On average, drug levels at these sites were 10 to 100 times higher than less contaminated sites.
Dr. Erinn Richmond, co-author of the study, said, "Each insect and spider we tested contained drugs.
"Even seemingly pristine sites were contaminated, probably because people live in the park's drainage zone and visit the park."
A platypus living in a stream that receives treated wastewaters could receive half of the recommended human dose of antidepressants daily – simply by consuming its normal diet with brook insects (pictured).
The pharmaceutical pollution is present in surface waters around the world, the researchers said.
Drugs enter our waterways as most wastewater treatment plants are not capable of removing them from the sewage.
Wastewater tanks, aging pipes and sewer overflows all add to the problem.
Scientists say they can deliver drugs to spiders, birds, bats and other power seekers when the insects appear as flying adults.
In the rivers studied, platypus and brown trout also fed on aquatic insects.
By combining the levels of drugs found in river insects with known dietary needs for platypuses and trout, the team estimated the drug exposure.
Dr. Rosi said, "A platypus living in a stream that receives treated wastewaters could receive half of the recommended human dose of antidepressants daily – just by eating its normal insect feed.
"This intake probably has biological effects."
The caddisfly, a globally distributed aquatic insect, was tested in the study.
Dr Richmond said, "Similar insects are found in freshwater around the world.
"This is not a specific problem for Australia. It is representative of what is likely to happen where people are taking drugs.
"And it's probably an underrated one. We tested only 98 pharmaceuticals – thousands are in circulation."
The results were published in the journal Nature Communications.