title: Intra- and inter-basin mercury comparisons: Importance of basin scale and time-weighted methylmercury estimates.
abstract: To assess inter-comparability of fluvial mercury (Hg) observations at substantially different scales, Hg concentrations, yields, and bivariate-relations were evaluated at nested-basin locations in the Edisto River, South Carolina and Hudson River, New York. Differences between scales were observed for filtered methylmercury (FMeHg) in the Edisto (attributed to wetland coverage differences) but not in the Hudson. Total mercury (THg) concentrations and bivariate-relationships did not vary substantially with scale in either basin. Combining results of this and a previously published multi-basin study, fish Hg correlated strongly with sampled water FMeHg concentration (ρ = 0.78; p = 0.003) and annual FMeHg basin yield (ρ = 0.66; p = 0.026). Improved correlation (ρ = 0.88; p < 0.0001) was achieved with time-weighted mean annual FMeHg concentrations estimated from basin-specific LOADEST models and daily streamflow. Results suggest reasonable scalability and inter-comparability for different basin sizes if wetland area or related MeHg-source-area metrics are considered.
authors.affiliation: U.S. Geological Survey, 720 Gracern Rd, Columbia, SC 29210, USA. pbradley@usgs.gov
authors.forename: Paul M
authors.initials: PM
authors.lastname: Bradley
authors.forename: Celeste A
authors.initials: CA
authors.lastname: Journey
authors.forename: Mark E
authors.initials: ME
authors.lastname: Brigham
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Burns
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Button
authors.forename: Karen
authors.initials: K
authors.lastname: Riva-Murray
mesh_terms: D004784:Environmental Monitoring; D008628:Mercury / Q000032:analysis*; D008767:Methylmercury Compounds / Q000032:analysis*; D009518:New York; D045483:Rivers / Q000737:chemistry; D013022:South Carolina; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data
chemical_list: D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury