Scientific Investigations Report 2011-5082
Table 12. Minimum, median, and maximum concentrations of priority trace elements detected in Hood River basin, Oregon, surface waters and national and State water-quality standards and exposure responses from literature. [Source: Oregon Department of Environmental Quality, 2004; U.S. Environmental Protection Agency, 2005a, 2009b. All concentrations reported in micrograms per liter. Abbreviations: USEPA, U.S. Environmental Protection Agency; CMC, criteria maximum concentration; CCC, criterion continuous concentration; wk, week; m, month; h, hour; d, day; LC50, 50 percent lethal concentration; —, not detected, no water-quality standard or no literature values]
1Hardness-dependent criterion based on hardness range of 15-60 mg/L, the general range of hardness values available in the basin from 1999 through 2009. Criteria were calculated using USEPA (2005a) National Recommended Water-quality criteria Appendix B: Parameters for Calculating Freshwater Dissolved Metals Criteria That Are Hardness-Dependent. The USEPA reports these criteria based on 100 mg/L hardness as CaCO3. 2USEPA criteria for copper were calculated using the hardness-dependent formula. The USEPA now uses the Biotic Ligand Model (BLM), which uses 11 parameters to calculate copper criteria. The BLM could not be used here because data for all 11 parameters in the basin do not exist. 3Oregon hardness-dependent criteria are based on older USEPA guidelines, which use different calculation parameters than USEPA currently uses. Oregon criteria refer to total recoverable metal concentration, while the USEPA uses dissolved concentration (Oregon Department of Environmental Quality, 2006). |
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