A new report by a joint U.S.-Canadian organization reveals that not all prescription drugs and other chemicals are removed by water treatment plants, leaving a significant proportion of the chemicals in treated effluent.
The International Joint Commission (IJC), which regulates shared water uses, has raised concerns that the Great Lakes and other bodies of water are being contaminated with so-called "chemicals of emerging concern" (CECs), which may eventually show up in drinking water. CECs have recently come under scrutiny because of their suspected negative impact on the environment, although their specific effect on health is not clear. The chemicals are often used in household items, agriculture, personal care products, pharmaceuticals and flame retardants.
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Between 2009 and 2011 the IJC carried out a study looking at how effective wastewater treatment plants in the area of the Great Lakes were and how successful they were in removing 42 CECs through different technologies. At least six of the chemicals, including two antibiotics, an antibacterial drug, an anti-seizure drug, an anti-inflammatory drug and a herbicide, were removed very rarely and frequently remained in the treated effluent. A further five CECs also had a low rate of removal but were not often detected in the treated water. The study concluded that about half of the examined chemicals were likely to be picked up and removed in municipal wastewater treatment plants.