Spatial trends and impairment assessment of mercury in sport fish in the Sacramento–San Joaquin Delta watershed

• Published in: Environmental pollution (1987) Vol. 157; no. 11; pp. 3137 - 3149
• Main Authors: Melwani, A.R., Bezalel, S.N., Hunt, J.A., Grenier, J.L., Ichikawa, G., Heim, W., Bonnema, A., Foe, C., Slotton, D.G., Davis, J.A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-11-2009; Elsevier
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; Assessments; Bass; bioaccumulation; Biological and medical sciences; Brackish; California; Deltas; Ecotoxicology, biological effects of pollution; Environmental Monitoring; Fish; Fishes - classification; Fishes - metabolism; food webs; Freshwater; freshwater fish; Fundamental and applied biological sciences. Psychology; game fish; General aspects; geographical variation; heavy metals; Human health; Hydrology; Lepomis macrochirus; linear models; Mercury; Mercury - analysis; Mercury - metabolism; Mercury - toxicity; Micropterus salmoides; Morone saxatilis; Muscles - chemistry; Muscles - metabolism; Oncorhynchus mykiss; predator-prey relationships; prediction; Regional; risk assessment; rivers; Rivers - chemistry; Sacramento–San Joaquin Delta; Spatial trends; temporal variation; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity; watershed hydrology; Watersheds; California; USA, California, Mokelumne R; INE, USA, California, Sacramento-San Joaquin Delta; Fish; Human health; Sacramento–San Joaquin Delta; Spatial trends; Mercury; Human; Heavy metal; Freshwater environment; Trace element; Aquatic environment; Pollutant; Vertebrata; Pollution; Health and environment; Delta; Pisces; Trend analysis; Watershed; Environment; Poison; Sacramento-San Joaquin Delta; Public health
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2009.05.013

A three-year study was conducted to examine mercury in sport fish from the Sacramento–San Joaquin Delta. More than 4000 fish from 31 species were collected and analyzed for total mercury in individual muscle filets. Largemouth bass and striped bass were the most contaminated, averaging 0.40 μg/g, while redear sunfish, bluegill and rainbow trout exhibited the lowest (<0.15 μg/g) concentrations. Spatial variation in mercury was evaluated with an analysis of covariance model, which accounted for variability due to fish size and regional hydrology. Significant regional differences in mercury were apparent in size-standardized largemouth bass, with concentrations on the Cosumnes and Mokelumne rivers significantly higher than the central and western Delta. Significant prey–predator mercury correlations were also apparent, which may explain a significant proportion of the spatial variation in the watershed.
Regional differences in sport fish mercury were found in the Sacramento–San Joaquin Delta.