A braid that lives in a stream or a stream of wastewater can be exposed to 50% of the daily dose of antidepressants in human forms, only if they eat their normal insect feed, according to new research.
A team of scientists, led by researchers at Monash University, analyzed insects and nearby crawlers found in six Melbourne streams for traces of 98 different types of pharmaceutical products.
The research, published in the center of Nature Communications, revealed 69 different types of pharmaceutical products in insects and 66 types of spiders. It is suggested that pharmaceutical products were moved to pauve after they consumed insects.
The scientists then evaluated what potential exposure might be for the main species fed to those invertebrates in these streams: platypus and brown trout.
"There are many studies that exist to tell us that pharmaceutical products are in the water," said study author Erinn Richmond. "What we did not know was whether these pharmaceuticals were moving through water networks for food?
"One I think that I think it's alarming because of this study is just the number and type of drugs discovered in these insects.
"We found 69 different pharmaceuticals."
The analyzed flows have different levels of exposure to wastewater from the treatment plant or other wastewater sources, such as leaking septic tanks or infrastructure.
The number of drug types found and their concentration are greatest in insects collected in areas downstream from the wastewater treatment plant or in large populated septic tank leakage areas.
However, Richmond said that even the site expected to be free of contamination – Lirebird Creek in the Dandenong Ranges National Park – has been discovered to have insects in which 41 different pharmaceutical compounds have been discovered.
Types of drugs that have been discovered include muscle relaxants, antihistamines, paracetamol, beta blockers, and a small amount of drugs for Parkinson's disease.
For some classes of drugs, such as antidepressants, researchers have estimated that trout and plutum can consume even half a day's therapeutic dose for humans.
Scientists have said that pharmaceutical products that pass through the food network are not a problem specific to Australia and could occur wherever medicines are being consumed.
They said that the amount of drugs they discovered were also "undoubtedly underestimated" given that they tested only 98 compounds, and over 900 pharmaceuticals were subsidized by Australian pharmaceutical benefits. More than 1,400 are approved by the Food and Drug Administration in the United States.
However, Richmond said that the consequences of exposure to the wilderness should be sought for further research.
She said that individuals should be aware of how to dispose of unused pharmaceutical drugs and that more stringent environmental guidelines might be needed.
"As we continue, global pharmaceutical use is rising," she said. "There are benefits to taking drugs for us, but the research clearly shows that these pharmaceutical agents go through these food nets to detect insects, spiders, and potentially birds, blind mice, fish, and platypus."