Mercury speciation and biomagnification in the food web of Caddo Lake, Texas and Louisiana, USA, a subtropical freshwater ecosystem

• DOI: 10.1002/etc.477
• Publication Date: 2011-02-09T12:02:20Z
• Authors: Matthew M Chumchal; Thomas R Rainwater; Steven C Osborn; Aaron P Roberts; Michael T Abel; George P Cobb; Philip N Smith; Frank C Bailey
• Keywords: Biomagnification; Methylmercury; Mercury; Dry weight

We studied the biomagnification of total mercury and methylmercury in a subtropical freshwater lake, Caddo Lake, Texas Louisiana, USA. The present study is unique that it not only included invertebrates (seven species) fish (six but also an amphibian (one species), reptiles (three mammals species). Nonfish vertebrates such as those are often assessments trophic transfer Hg. Mean position (determined using stable isotopes nitrogen) ranged from 2.0 (indicative primary consumer) to 3.8 tertiary consumer). Hg concentrations 36 3,292 ng/g dry weight muscle whole body 150 30,171 liver. Most whole-body tissue was found methylmercury, at least 50% liver inorganic form (with exception largemouth bass, Micropterus salmoides). Mercury were positively correlated with position, indicating occurs food web Lake. magnification factors (FWMFs; slope relationship between mean concentration position) for both similar observed other studies. Because most consumers FWMF significantly different Some examined had low their tissues invertebrates, whereas others previous studies have been associated negative health consequences fish.