COS 80-4 - Temporal variation of pharmaceuticals in an urban and agriculturally influenced stream

Thursday, August 5, 2010: 9:00 AM
334, David L Lawrence Convention Center
Allison Veach, Kansas State University and Melody Bernot, Biology, Ball State University, Muncie, IN
Background/Question/Methods

Pharmaceuticals enter freshwater ecosystems via multiple sources including disposal of surplus drugs, human

excretion into sewage, and runoff associated with therapeutic treatment of livestock.  Previous studies consistently

demonstrate the prevalence of pharmaceuticals in freshwater but we do not yet know how concentrations vary

over time within a given system.  Two sites in central Indiana with varying land use in the surrounding watershed

were sampled monthly for pharmaceutical concentrations and stream physiochemical parameters.  Sediment

samples were also collected at each sampling event for measurement of 15N content.

Results/Conclusions

Significant differences in pharmaceutical compounds detected and total concentrations were identified both

between sites (spatial variation) and within each site (temporal variation).  Pharmaceutical compounds detected

included acetaminophen (2.1-460 ng/L), carbamazepine (1.1-2.7 ng/L), caffeine (11-400 ng/L), cotinine (2.1-12

ng/L), DEET (23-150 ng/L), gemfibrozil (1.2-4.9 ng/L), ibuprofen (1.8-42 ng/L), sulfamethoxazole (1.4-15 ng/L),

sulfamethazine (1.8 ng/L), triclosan (9.1-22 ng/L), and trimethoprim (3-9.7 ng/L).  Across sites, water column

dissolved oxygen correlated with caffeine (p=0.026), carbamazepine (p=0.006), cotinine (p=0.026), and

sulfamethoxazole (p=0.056) concentrations.  Overall, total pharmaceutical concentrations within the agriculturally

influenced site were highest in winter whereas the urban site had the highest in summer.  Pharmaceuticals present

in freshwater may not only affect aquatic organisms, but may also enter drinking water intakes resulting in

unintentional consumption by humans.  A more comprehensive understanding of spatial and temporal variability of

these contaminants is needed to mitigate potential effects.

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