Methylation and demethylation of mercury under controlled redox, pH, and salinity conditions

Journal Article · Sat Dec 01 04:00:00 EST 1984 · Appl. Environ. Microbiol.; (United States)

OSTI ID:6098438

Compeau, G; Bartha, R

In estuarine sediments, the microbially mediated processes of methylation, demethylation, and volatilization determine the state and overall toxicity of mercury pollutants. The effects of redox potential (E/sub h/) and salinity on the above microbial processes were investigated in reactors constructed to allow for continuous monitoring and adjustment of the pH (6.8) and E/sub h/ of freshly collected estuarine sediments. For measurments of methylation and demethylation activity, sediment slurries adjusted to appropriate salinity were spiked with HgCl/sub 2/ or CH/sub 3/HgCl, respectively, and were incubated in the reactors. Methylmercury was measured by gas chromatography. Volatilized elemental mercury (Hg/sup 0/) was trapped and determined by cold vapor atomic absorption spectrometry. Volatilization of Hg/sup 0/ and CH/sub 3/HgCH/sub 3/ were found to be minimal. Methylation of Hg/sup 2 +/ was favored at E/sub h/-220 mV as compared to +110 mV. At -220 mV, high salinity (2.5%) inhibited methylation, and low salinity (0.4%) favored it. At +110 mV, the salinity effect was less pronounced. Demethylation of CH/sub 3/HgCl was favored at +110 mV regardless of the salinity level. Low redox potential under low salinity conditions inhibited demethylation, but high salinity reversed this inhibition. These findings are helpful for interpreting and predicting the behavior of mercury pollutants in estuarine sediments.

• Research Organization: Rutgers Univ., New Brunswick, NJ
• OSTI ID: 6098438
• Journal Information: Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 48:6; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ABSORPTION SPECTROSCOPY
BIODEGRADATION
BIOREACTORS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DECOMPOSITION
ELEMENTS
ESTUARIES
EVAPORATION
GAS CHROMATOGRAPHY
MERCURY
MERCURY COMPOUNDS
METALS
METHYLATION
METHYLMERCURY
ORGANIC COMPOUNDS
ORGANIC MERCURY COMPOUNDS
PH VALUE
PHASE TRANSFORMATIONS
REDOX POTENTIAL
RESPONSE MODIFYING FACTORS
SALINITY
SAMPLING
SEDIMENTS
SEPARATION PROCESSES
SPECTROSCOPY
SURFACE WATERS