Prioritizing Pharmaceutical Contaminants in Great Lakes Tributaries Using Risk-Based Screening Techniques.

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Water Quality Assessment

Background:

• Pharmaceuticals are frequently detected in aquatic environments.
• Assessing the ecological risk of these contaminants is crucial for water resource management.

Purpose of the Study:

• To evaluate the ecological relevance of detected pharmaceuticals in Great Lakes tributaries.
• To identify areas with high pharmaceutical contamination and inform resource managers.

Main Methods:

• Monitored 257 pharmaceuticals across 44 sampling sites in 16 Great Lakes tributaries.
• Utilized ECOTOX Knowledgebase and ToxCast database for benchmark comparisons.
• Analyzed pharmaceutical concentrations in relation to flow rates and wastewater effluent.

Main Results:

• 110 pharmaceuticals were detected; ten were identified as high-priority based on biological effects benchmarks.
• Highest pharmaceutical concentrations were found in Lake Erie, southern Lake Michigan, and Lake Huron tributaries.
• Low-flow periods and wastewater effluent correlated positively with higher pharmaceutical concentrations.

Conclusions:

• Ten pharmaceuticals pose the greatest potential ecological risk in the studied Great Lakes tributaries.
• Contamination levels are influenced by flow dynamics and wastewater discharge.
• Further research is needed for high-priority pharmaceuticals and those lacking ecotoxicological data.