Stream life taking in pharmaceutical pollution, study finds
Insects that live near streams are absorbing a cocktail of drugs and medicines, new research shows.
The pollutants, including antibiotics and antidepressants, are spreading through the food chain as predators such as birds, bats and fish feed on the contaminated insects.
Drugs enter the environment because most wastewater treatment facilities are not equipped to remove them from sewage, the researchers said. Septic tanks, ageing pipes, and sewer overflows contribute to the problem.
Study co-author Dr Emma Rosi from the Cary Institute of Ecosystem Studies in the United States, said: “Stream life is swimming in a mixture of pharmaceuticals.”
The research was carried out in Australia, but pharmaceutical pollution is present in surface waters around the world, the researchers said.
Their analysis found up to 69 different pharmaceutical compounds in aquatic insects, and up to 66 compounds in spiders that spin their webs over streams to catch the emerging insects.
Dr Rosi said: “Our study is the first to show that this chronic drug pollution can concentrate in aquatic insects and move up food webs, in some cases exposing top predators to therapeutically-relevant doses.”
Dr Laurence Couldrick, chief executive of the Westcountry Rivers Trust, said the technology we rely on to remove pollutants from waste is not designed to cope with all the new chemicals from domestic and industrial sources and are easily overwhelmed by storm flows making them even less effective.
“Without installing the type of very expensive controls we have for drinking water, there is a considerable risk these pollutants will be in our environment,” he said.
“This is something that concerns us and I believe there are groups researching this in the UK but it is complex as the number of new pollutants is growing all the time.”
Dr Couldrick said the methods used by the Environment Agency to assess and measure river water were “simplistic” and likely to miss pollutants.
Drugs can accumulate as they are passed on and build up through the food chain from prey to predator and potentially on to us.
“It is uncertain what the impacts to us could be as it depends on the dose we receive,” he said.
So-called “integrated constructed wetlands” might offer some improvement, Dr Couldrick said. These are schemes where waste water is used to create wetlands, where some of the contaminants are trapped and, in some cases, turned into useful products.
“I’m trying to develop a project on these and those leading the field think they will do well with the increasing cocktail of pollutants but this is yet unproven,” Dr Couldrick said.
Maritime and Environment Correspondent ‘The number of new pollutants is growing all the time’
Dr Laurence Couldrick