Methylmercury in Mosquitoes Related to Atmospheric Mercury Deposition and Contamination

• Published in: Environmental science & technology Vol. 39; no. 9; pp. 3034 - 3039
• Main Authors: Hammerschmidt, Chad R, Fitzgerald, William F
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.05.2005
• Subjects: Animal, plant and microbial ecology; Animals; Anopheles crucians; Applied ecology; Aquatic ecosystems; Atmosphere; Biological and medical sciences; Comparative analysis; Culex nigripalpus; Culicidae; Culicidae - chemistry; Diptera; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Environmental Monitoring; Environmental science; Female; Florida; Fundamental and applied biological sciences. Psychology; Mercury; Mercury - analysis; Mercury - pharmacokinetics; Methylmercury Compounds - analysis; Methylmercury Compounds - pharmacokinetics; Mosquitoes; Ochlerotatus atlanticus; Terrestrial environment, soil, air; Tissue Distribution; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - pharmacokinetics; North America; America; Florida; Alaska; California; United States > US; Michigan; USA; USA, California, Lake Cty; USA, California; USA, Florida; USA, Michigan; Arctic; USA, Alaska; Insecta; Biological indicator; Atmospheric deposition; Contamination; Heavy metal; Arthropoda; Culicidae; Pollution source; Air pollution; Invertebrata; Biological accumulation; Mercury; Diptera; Organic compounds; Chemical contamination
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0485107

A connection between loadings of inorganic Hg, especially from the atmosphere, and accumulation of methylmercury (MeHg) in aquatic biota has not been firmly established. Mosquitoes (Diptera:  Culicidae) may be a useful indictor of Hg contamination or MeHg accumulation in aquatic ecosystems because they have aquatic life stages, and their ubiquitous distribution permits sampling across wide ranges of climate, biological productivity, and atmospheric Hg deposition. We examined MeHg in adult mosquitoes from subtropical (Florida), maritime (California), continental (Michigan), and arctic (Alaska) regions of North America that span a range in wet atmospheric Hg deposition (1.5−15 μg m-2 y-1). More than 90% of the Hg in mosquitoes was MeHg, and concentrations varied among locations. Levels of MeHg differed among mosquito species at six sites in northwest Florida (Ochlerotatus atlanticus < Culex nigripalpus < Anopheles crucians); this may be related to differences in biogeochemical characteristics of the aquatic habitat that affect dietary accumulation of MeHg during the larval stage. Mosquito MeHg was related positively to wet atmospheric Hg deposition among locations where atmospheric deposition is the principal source of Hg, and it was greatly enhanced in Hg-polluted environs near the Sulphur Bank Mine in Lake County, California. These results suggest that MeHg in mosquitoes may be a useful and sensitive indicator of Hg loadings to aquatic systems, including that derived from atmospheric deposition.