MERCURY IN AQUATIC SYSTEMS: ENVIRONMENTAL FACTORS AFFECTING MERCURY METHYLATION.

Authors

  • Marcio Rodrigues Miranda Universidade Federal do Rio de Janeiro
  • Sergio Augusto Coelho-Souza Universidade Federal do Rio de Janeiro
  • Jean Remy Daveé Guimarães Universidade Federal do Rio de Janeiro.
  • Raquel R.S. Correia Universidade Federal do Rio de Janeiro
  • Diana Oliveira Universidade Federal do Rio de Janeiro

Keywords:

methylmercury, microorganisms, global cycle, methylcobalamin, inorganic mercury, speciation.

Abstract

Methylmercury is a highly neurotoxic contaminant that accumulates in organisms and biomagnifies along the food chain. Methylmercury is formed through the transfer of a methyl group to the inorganic mercury (Hg2+). This reaction is mainly mediated by microorganisms living in anoxic environments like bottom sediments and macrophytes rhizosphere. Abiotic methylation can also occur, however in most cases with lower rates than biological methylation. Mercury methylation rates in aquatic systems are influenced by both the speciation and bioavailability of mercury. Many interrelated environmental variables such as biological activity, nutrient availability, pH, temperature, redox potential, and the presence of inorganic and organic complexing agents can also affects the net rate of methylmercury production. Which factors dominate methylmercury production is likely to differ from one ecosystem to other.

Published

2009-12-11