Spencer A. Peterson

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The ability of selenium (Se) to moderate mercury (Hg) toxicity is well established in the literature. Mercury exposures that might otherwise produce toxic effects are counteracted by Se, particularly when Se:Hg molar ratios approach or exceed 1. We analyzed whole body Se and Hg concentrations in 468 fish representing 40 species from 137 sites across 12(More)
Although mercury contamination of fish is a widespread phenomenon, its regional evaluation is hindered by the reluctance of permitting agencies to grant collection permits, problems in securing adequate freezer space, and time to process whole, large fish or filets. We evaluated mercury concentrations in 210 filet biopsies from 65 sites in 12 western states(More)
We collected and analyzed 2,707 large fish from 626 stream/river sites in 12 western U.S. states using a probability design to assess the regional distribution of whole fish mercury (Hg) concentrations. Large (>120 mm total length) fish Hg levels were strongly related to both fish length and trophic guild. All large fish that we sampled exceeded the wet(More)
Bioassays were used in a three-phase research project to (a) assess the comparative sensitivity of test organisms to known classes of chemicals, (b) determine if the chemical components in field soil and water samples of unknown chemical composition could be inferred from laboratory studies using pure chemicals and (c) investigate kriging (a relatively new(More)
We classified 235 randomly selected lentic waterbodies (>1 ha) in the Northeast USA as human created, or natural. We compared geographic extent and distribution, morphology and hydrology, trophic state, and fish assemblage metrics of impoundments and natural drainage lakes. We estimated that 46% of the 10 608 (±1695; 95% CI) lentic waterbodies in the region(More)
Research priorities in ecology and environmental sciences for the future are formulated. The priorities for both fundamental and applied ecology are proposed. The list of priorities includes 50 items. The priorities are relevant to terrestrial, aquatic, and general ecology. The list of priorities is helpful when grant proposals are being prepared,(More)
We conducted a probability survey of 154 Oregon, USA, stream and river sites to assess the spatial extent of mercury (Hg) contamination in fish tissue. Samples consisted of whole-fish analyses of both small (<120 mm) and large (>120 mm) fish at each site, when both were present. Overall, Hg levels (microgram/g) in small fish (mean = 0.031; standard(More)
Current recommended holding times for the analysis of total mercury (Hg) in fish tissue ranges from 28 to 180 days. In 2006, we evaluated the effect of an extended holding time on Hg concentrations by reanalyzing whole-fish wet homogenates that were analyzed originally in 2002 and had been stored frozen at -20 degrees C since that time. Seven species, 13-15(More)
Three different laboratory earthworm protocols for assessing the potential toxicity of environmental samples were evaluated using Eisenia fetida. The 48-h Contact Test (CT) is a short test and may indicate the presence of water-soluble chemicals. The 14-day Soil Test (ST) is best suited to assess chemical impacts of either known or unknown chemicals in(More)
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