R4 AM Occurrence and Fate of Pharmaceutical and Other Emerging Wastewater Contaminants in Aquatic Systems
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in Ballroom 4

(ROT-1117-834293) Transport and fate of selected priority pharmaceuticals in the US environment.

Roth, C.¹, Dong, Z.¹, Senn, D.¹, MacLeod, M.², Shine, J.¹, ¹ Harvard University, Boston, MA, USA² Swiss Federal Institute of Technology (ETHZ), Zurich, Switzerland

ABSTRACT- Pharmaceuticals enter the environment after use or unused after disposal mainly through the wastewater system. As their removal in wastewater treatment plants (WWTP) is often not 100% they pose a risk to the aquatic environment. A range of pharmaceuticals used in the US market has been determined as top-priority compounds based on information such as sales, metabolism, degradation in WWTPs and toxicity. The environmental exposure of a selection of these pharmaceuticals is assessed by a multimedia fate and transport model. With the BETR-North America model, environmental distribution in seven compartments in 24 North American regions is calculated based on refined input parameters. These parameters include degradation in the environment, including estimates of biodegradation, photodegradation and other reactions of the mostly charged species. A range of estimation methods is used to approach speciation and possible degradation processes. Partitioning in various environmental sorbents is estimated with poly-parameter linear free energy relationships (LFER), an approach novel in multimedia modeling. Poly-parameter LFERs are not only based on one parameter such as the octanol-water partitioning coefficient, but include several parameters accounting for the diverse intermolecular interactions taking place in sorption of organic pollutants. Results show the exposure of the aquatic system to these pharmaceuticals, some of which have not yet been examined for their occurrence in and potential risk to the environment.

Key words: Pharmaceuticals, environmental fate, estimation methods