Fate of Pharmaceuticals and Endocrine Disrupting Compounds during Drinking Water Treatment

The presence of pharmaceuticals and endocrine disrupting compounds (EDCs) in drinking water has received renewed interest during the past year. Despite popular press concerns over the occurrence of trace levels of such compounds, scientists and regulators are not sure what risk, if any, is posed by their presence. A better understanding of their occurrence in drinking water treatment plants and fate during treatment is needed. To that end, we will present results from several years of work detailing the occurrence and fate of pharmaceuticals and EDCs in drinking water treatment plants throughout the United States, as well as their fate during both conventional and advanced treatment processes. Concentrations of 61 compounds were measured in the source water, finished water, and distribution system water of 19 drinking water treatment plants in the United States, representing the drinking water for 28.4 million Americans. Of the ten compounds that were detected in at least 50% of source waters (sulfamethoxazole, atenolol, trimethoprim, meprobamate, dilantin, carbamazepine, atrazine, gemfibrozil, naproxen, estrone, and TCEP), only three (meprobamate, dilantin, and atrazine) were detected in at least 50% of finished water samples. Median concentrations of the ten most frequently detected compounds were below 10 ng/L, except for sulfamethoxazole and TCEP in raw water (12 and 120 ng/L, respectively), as well as atrazine in raw, finished and distribution system water (32, 49, and 49 ng/L, respectively). In terms of treatment technologies, ozone is more effective than chlorine, and is much more effective than chloramine for removal of pharmaceuticals and EDCs. Advanced oxidation processes (ozone/peroxide, UV/peroxide, UV/titanium dioxide photocatalysis) are highly effective at removing the majority of contaminants evaluated. Reverse osmosis and nanofiltration membrane systems are also very efficient at removal of the pharmaceuticals and EDCs, whereas ultrafiltration and nanofiltration systems are not.