Citation:

Glassmeyer, S AND J A. Shoemaker. EFFECTS OF CHLORINATION ON THE PERSISTENCE OF PHARMACEUTICALS IN THE ENVIRONMENT. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 74(1):24-31, (2005).

Impact/Purpose:

The overall objective of this task is to provide the Agency with background information on the fate of pharmaceuticals in drinking water systems which can be used to determine if pharmaceuticals should be entered on the 2003 or future CCLs.

Description:

In the past decade, the identification of pharmaceuticals in surface (Jones et al. 2001; Ternes 1998), ground (Sacher et al. 2001) and drinking (Heberer 2002) waters has attracted the attention of both the scientific and lay communities. Although the concentrations of these compounds are very small (typically less than 1 g/L), their presence is a reminder that many people's drinking water was once another community's wastewater. To date, the majority of the studies looking for pharmaceutical compounds have been conducted in Europe. Due to the differences in drinking and wastewater treatment technologies, as well as the dosage level and types of pharmaceuticals administered, it is difficult to estimate the concentrations of pharmaceuticals present in the waters of the United States based on European data. The United States Geological Survey (USGS) has recently conducted the first nationwide reconnaissance of pharmaceuticals (both human and veterinary) and other wastewater components in the United States (Kolpin et al. 2002). They found at least one of their target non-prescription drugs in approximately 80% of the 139 streams sampled. At least one prescription drug was found in over 30% of the streams and at least one antibiotic was found in over 50% of the sampled locations. While the sample locations were biased towards areas that were expected to yield detections (such as downstream from urban centers and areas if dense livestock populations), this study demonstrates the pervasiveness of pharmaceuticals in the aquatic environment of the United States.

Due to the low concentrations of pharmaceuticals in the environment, most of the mass spectrometry methods that have been developed only measure known target compounds. These methods only monitor selected ions, which helps to improve detection limits. However, this improvement comes at a price. Since only specified ions are monitored, in studies where the influent and effluent of waste and drinking water treatment plants were analyzed, only removal efficiencies can be reported (Ternes 1998; Ternes et al. 2002; Zwiener and Frimmel 2000). The ultimate fate of these compounds, that is whether they were degraded into something harmless, or potentially transformed into something more toxic, cannot be determined.

In the United States, chlorine is commonly used to disinfect sewage, as well as drinking water (USEPA 1999a). Although this procedure removes pathogens, the chlorine can also react with compounds in the water. As past research on disinfection byproducts in water has shown, this addition of chlorine may increase the toxicity of the compounds (Clark et al. 2001; Nieuwenhuijsen et al. 2000). Thus, if the removal of pharmaceuticals in waste and drinking water treatment plants is due to the chlorination of the compounds, the potential negative human health impacts may be increased rather than decreased. Mass spectrometry is useful in chlorination experiments, because it can easily detect the formation of new degradation products which contain chlorine atoms.

The purpose of this work was to determine via benchtop experiments the fate of pharmaceuticals during chlorination. This information can be used to focus occurrence studies on the analytes that have a higher probability of persisting through treatment (and thus being found in the environment), as well as the disinfection/ degradation byproducts that might be unknowingly produced.

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