Our vital freshwater ecosystems are being threatened by high concentrations of pharmaceutical waste. This should be cause for great concern and if current trends persist, the amount of pharmaceutical effluence leaching into waterways could increase by two-thirds before 2050. These findings were part of a study presented to the European Geosciences Union conference in Vienna on 10 April 2018 by Francesco Bregoli, a researcher at the IHE Delft Institute for Water Education in the Netherlands. Bregoli is leader of an international team that has developed a method for tracking drug pollution ‘hotspots’. He says that technology alone cannot solve the problem and that a substantial reduction in the consumption of pharmaceutical products is needed. However, with pharmaceutical use growing worldwide, and sales expected to increase 6.3% annually (2016 to 2022), more and more drugs are likely to be entering the environment.
Pharmaceuticals are ubiquitous in wastewater being deposited primarily via human urine and faeces. The active ingredients from leftover pills thrown in patients’ trash or even hospital waste also finds its way into waterways. Sewage treatment plants remove some pharmaceuticals from water during basic filtering processes but many pass through unhindered. From sewage plants and landfills, drugs make their way into streams, rivers, lakes, seawater, and even into drinking water.
A large number of these drugs – analgesics, antibiotics, anti-platelet agents, hormones, psychiatric drugs, antihistamines – have proven to be dangerous for wildlife. Endocrine disruptors, for example, have induced sex changes in fish and amphibians. Bregoli and his team used the common anti-inflammation drug, diclofenac, as a proxy to estimate the presence and spread of other medications in freshwater ecosystems. Both the European Union and the US Environmental Protection Agency have identified diclofenac as an environmental threat. Veterinary use of it has driven a sub-species of vultures on the Indian subcontinent to the brink of extinction, and more than 10,000 km of rivers around the world have concentrations of diclofenac above the EU 'watch list' limit of 100 nanograms a litre, the new research found.
Diclofenac emissions are similar to any of thousands of pharmaceuticals and personal care products. Global consumption of diclofenac tops 2,400 tonnes a year. Several hundred tonnes remain in human waste, and only a small fraction – about 7% – of that is filtered out by treatment plants. Another 20% is absorbed by ecosystems, and the rest goes into oceans. Bregoli and his team developed the computer model to predict current and future pharma pollution based on criteria such as population densities, sewage systems and drugs sales. They compared the results to data gathered from 1,400 spot measurements of diclofenac toxicity taken from around the world. Most of the data points were in Europe and North America. Pollution levels are likely to be substantially higher in much of Latin America, Africa and Asia where less than a quarter of waste water is treated, and with technology unable to filter out most pharmaceuticals.
In other research presented at the conference, scientists found that the rapid expansion of sewage systems in large urban areas has sharply raised river pollution because much of it is not adequately treated. “In 2000, sewage was a source of pollution in about 50% of the rivers in the world,” said Maryna Strokal, a scientist at Wageningen University and Research in the Netherlands. “By 2010, sewage was a source of pollution in almost all rivers worldwide.” Antibiotics and chemicals waste is also driving the evolution of drug-resistant bacteria, UN Environment warned in a study in December. Between 70% and 80% of all antibiotics consumed by humans and farm animals – thousands of tonnes – find their way into natural environments.
'Legacy' pollutants such as polychlorinated biphenyls (PCBs) and DDT – so-called because they persist for years and accumulate in the environment -- have been banned in many countries. Because they are designed to maintain their strength and efficacy en route from manufacturer to pharmacy to medicine cabinet, pharmaceuticals also do not degrade and may persist for years (even decades) in the environment. To make matters worse, our modern environment contains a mixture of, not only pharmaceuticals, but pesticides, industrial by-products and many other chemicals. This can lead to dangerous concoctions where drugs interact with one another, with bacteria, and with basic environmental elements such as water. Chemical and biological reactions can result creating new chemicals with new properties. Such metabolites can sometimes be more toxic than their parent compounds.
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