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U.S. Department of Energy
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Environmental significance of the potential for mer (Tn21)-mediated reduction of Hg (2+) to Hg in natural waters

Technical Report ·
OSTI ID:7266249
The role of mer(Tn21) in adaptation of aquatic microbial communities to Hg2+ was investigated. Elemental mercury was the sole product of Hg2+ volatilization by freshwater and saline microbial communities. Bacterial activity was responsible for biotransformation because most microeukaryotes did not survive the exposure conditions, and removal of larger microbes (> 1 microgram) from adapted communities did not significantly (P > 0.01) reduce Hg2+ volatilization rates. DNA sequences homologous to mer(Tn21) were found in 50% of Hg2+ resistant bacterial strains representing two freshwater communities, but in only 12% of strains representing two saline communities (difference highly significant, P < 0.001). Thus, mer(Tn21) played a significant role in Hg2+ resistance among strains isolated from freshwaters where microbial activity had a limited role in Hg2+ volatilization. In saline environments where microbially mediated volatilization was the major mechanism of Hg2+ loss, other bacterial genes coded for the biotransformation.
Research Organization:
Technical Resources, Inc., Gulf Breeze, FL (USA)
OSTI ID:
7266249
Report Number(s):
PB-90-129511/XAB
Country of Publication:
United States
Language:
English