Wastewater treatment plants need to assess the effectiveness of their treatment technologies to deal with an increasing number of “chemicals of emerging concern” (CECs) being discharged into the Great Lakes. That’s the conclusion of a recent report issued by the International Joint Commission (IJC), which assessed the effectiveness of existing wastewater treatment technologies in the Great Lakes Basin to remove CECs.
In the report, “Protecting Our Great Lakes: Assessing the Effectiveness of Wastewater Treatments for the Removal of Chemicals of Emerging Concern,” the IJC – an advisory body to the U.S. and Canadian governments on Great Lakes water quality – called for an assessment of three major activities:
- Development of an inventory of municipal wastewater treatment plants that discharge in the Great Lakes Basin;
- A survey of detailed operational data for selected wastewater facilities; and
- A comprehensive literature review and analysis of the effectiveness of various wastewater treatment technologies to remove the CECs.
According to the IJC report, such chemicals are found in products used daily in households, businesses, agriculture and industry. They include flame retardants, pharmaceuticals, personal-care products and pesticides. Of major concern is the fact that many of these chemicals enter the Great Lakes via treated water from wastewater treatment plants. In fact, treated sewage is often discharged into near-shore waters, which also provide a source of drinking water to the public.
A recent article on Straight.com quoted the IJC report as saying that treatment plants remove only about half of the prescription drugs and other newly emerging contaminants found in sewage. While the impact of these chemicals on human health and aquatic life is unknown, the IJC suggests that better wastewater treatment is needed.
Citing the IJC study, the article said that more than 1,400 wastewater treatment plants in the United States and Canada discharge 4.8 billion gallons of treated effluent into the Great Lakes Basin every day. Scientists reviewed 10 years of data from wastewater treatment plants worldwide to see how well they removed 42 compounds that are increasingly showing up in the Great Lakes.
“The weight of evidence suggests that at least half of the 42 substances examined in the present study are likely to be removed in municipal wastewater treatment plants,” the report’s authors wrote. That said, Antonette Arvai, lead author of the study, commented, “The compounds show up in low levels – parts per billion or parts per trillion – but aquatic life and humans aren’t exposed to just one at a time, but a whole mix. We need to find which of these chemicals might hurt us.”
According to the IJC report, six chemicals were detected frequently and had a low rate of removal in treated effluent: an herbicide, an antiseizure drug, two antibiotic drugs, an antibacterial drug and an anti-inflammatory drug. In addition, caffeine, acetaminophen, and estriol (a natural estrogen) were frequently detected in sewage, but had high removal rates. Triclosan, an antibacterial and antifungal compound found in some soaps, toothpastes, and other consumer products, and can act as a hormone disruptor in fish, had “medium removal efficiency.”
The IJC is guided by the Boundary Waters Treaty, signed by Canada and the United States in 1909. Its main responsibilities are regulating water levels and investigating transboundary issues and recommending solutions. The commission’s decisions take into account a variety of water uses, including drinking water, commercial shipping, hydroelectric power generation, agriculture, industry, fishing, recreational boating and shoreline property.
