Potential sources of methylmercury in tree foliage

Environ Pollut. 2012 Jan;160(1):82-7. doi: 10.1016/j.envpol.2011.09.013. Epub 2011 Oct 14.

Abstract

Litterfall is a major source of mercury (Hg) and toxic methylmercury (MeHg) to forest soils and influences exposures of wildlife in terrestrial and aquatic ecosystems. However, the origin of MeHg associated with tree foliage is largely unknown. We tested the hypothesis that leaf MeHg is influenced by root uptake and thereby related to MeHg levels in soils. Concentrations of MeHg and total Hg in deciduous and coniferous foliage were unrelated to those in soil at 30 urban and rural forested locations in southwest Ohio. In contrast, tree genera and trunk diameter were significant variables influencing Hg in leaves. The fraction of total Hg as MeHg averaged 0.4% and did not differ among tree genera. Given that uptake of atmospheric Hg(0) appears to be the dominant source of total Hg in foliage, we infer that MeHg is formed by in vivo transformation of Hg in proportion to the amount accumulated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Air Pollutants / analysis
  • Air Pollutants / metabolism
  • Ecosystem
  • Environmental Monitoring
  • Mercury / analysis
  • Mercury / metabolism
  • Methylmercury Compounds / analysis*
  • Methylmercury Compounds / metabolism
  • Ohio
  • Plant Leaves / chemistry*
  • Plant Leaves / metabolism
  • Soil Pollutants / analysis
  • Soil Pollutants / metabolism
  • Trees / chemistry*
  • Trees / metabolism

Substances

  • Air Pollutants
  • Methylmercury Compounds
  • Soil Pollutants
  • Mercury