Nitrate Controls Methyl Mercury Production in a Streambed Bioreactor

2011 ◽  
Vol 40 (5) ◽  
pp. 1586-1592 ◽  
Author(s):  
Rita Shih ◽  
William D. Robertson ◽  
Sherry L. Schiff ◽  
David L. Rudolph
Keyword(s):  
Methyl Mercury ◽  
Mercury Production

Methyl mercury production and loss in Arctic soil

2009 ◽  
Vol 407 (5) ◽  
pp. 1691-1700 ◽  
Author(s):  
Lindsay Oiffer ◽  
Steven D. Siciliano
Keyword(s):  
Methyl Mercury ◽  
Arctic Soil ◽  
Mercury Production

The Mercury Problem in Recently Formed Reservoirs of Northern Manitoba (Canada): Effects of Impoundment and Other Factors on the Production of Methyl Mercury by Microorganisms in Sediments

1988 ◽  
Vol 45 (1) ◽  
pp. 97-121 ◽  
Author(s):  
Togwell A. Jackson
Keyword(s):  
Organic Matter ◽  
Methyl Mercury ◽  
Inorganic Mercury ◽  
Oxygen Depletion ◽  
Main Stream ◽  
Minor Importance ◽  
River Diversion ◽  
Marked Rise ◽  
Aerobic Conditions ◽  
Mercury Production

Creation of hydroelectric reservoirs by enlargement of riverine lakes and flooding of adjacent forested land along the Churchill River diversion route has led to a marked rise in rates of methyl mercury production by microorganisms in sediments. This phenomenon has resulted primarily from stimulation of microbial activity by organic matter in submerged land areas and is due both to utilization of organic nutrients by methylators and to concomitant oxygen depletion. Release of mercury from scattered low-level sources in this organic matter is a secondary contributing factor. Compared with submerged terrestrial organics, organic matter from aquatic biota has only been of minor importance in promoting methyl mercury production. In some regions, clay and silt eroded from shoreline deposits have inhibited methyl mercury production appreciably. The aerobic conditions prevailing in well-flushed main-stream regions tend to increase the "availability" of sediment-bound inorganic mercury for methylation while decreasing the rate at which microbes are able to methylate the mercury; under less aerobic conditions in quiet backwater regions, the reverse is true.

Aeration prevents methyl mercury production in dental wastewater

2012 ◽  
Vol 47 (4) ◽  
pp. 598-604 ◽  
Author(s):  
Xiuhong Zhao ◽  
Karl J. Rockne ◽  
James L. Drummond
Keyword(s):  
Methyl Mercury ◽  
Mercury Production

Measurements of Specific Rates of Net Methyl Mercury Production in the Water Column and Surface Sediments of Acidified and Circumneutral Lakes

1987 ◽  
Vol 44 (4) ◽  
pp. 750-757 ◽  
Author(s):  
Luying Xun ◽  
N. E. R. Campbell ◽  
John W. M. Rudd
Keyword(s):  
Water Column ◽  
Water Samples ◽  
Methyl Mercury ◽  
Lake Acidification ◽  
Sediment Surface ◽  
Mercury Methylation ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Decreasing Ph ◽  
Mercury Production

Specific rates of mercury methylation and demethylation were determined for water and surficial sediment samples taken from several lakes located in the Experimental Lakes Area, northwestern Ontario. Specific rates of mercury methylation were found to increase with decreasing pH in epilimnetic water samples in which pH was adjusted prior to incubation and in epilimnetic water samples taken from lakes of different pH. Reduction of pH also increased methyl mercury production at the sediment surface. Both increases and decreases in pH reduced specific rates of mercury demethylation. However, these changes were smaller than for methylation. Proportionally, specific rates of methylation increased faster than increasing concentrations of Hg2+, while specific rates of mercury demethylation increased linearly with increasing concentrations of methyl mercury. Overall, this study predicts that the net rate of methyl mercury production in the water column and at the sediment–water surface will increase as a result of lake acidification, and this may at least partially explain why the mercury concentration of fish appears to increase during lake acidification.

scholarly journals Why the English–Wabigoon river system is still polluted by mercury 57 years after its contamination

FACETS ◽  
2021 ◽  
Vol 6 ◽  
pp. 2002-2027
Author(s):  
John W.M. Rudd ◽  
Carol A. Kelly ◽  
Patricia Sellers ◽  
Robert J. Flett ◽  
Bruce E. Townsend
Keyword(s):  
Surface Sediment ◽  
Methyl Mercury ◽  
Total Mercury ◽  
Inorganic Mercury ◽  
River System ◽  
Lake Surface ◽  
Riverbank Erosion ◽  
Plant Site ◽  
High Mercury ◽  
Mercury Production

Between 1962 and 1969, 10 tonnes of mercury were discharged from a chlor-alkali plant in Dryden, Ontario, to the English–Wabigoon River. Present-day fish mercury concentrations are amongst the highest recorded in Canada. In 2017, the Grassy Narrows Science Team found no evidence of ongoing discharges from the plant site to the river water, even though large quantities of mercury remain at the site. Instead, our data suggest that ongoing erosion of high mercury particles by the river, as it meanders through contaminated floodplains, is responsible for present-day transport of mercury to Clay Lake and to Ball Lake, located 154 km downstream. In Clay Lake, surface sediment total mercury concentrations and inflow water concentrations are still about 15 times above background (86 km downstream), and in Ball Lake mercury concentrations in sediments appeared to be still increasing. The remobilization of legacy inorganic mercury from riverbank erosion between Dryden and Clay Lake stimulates methyl mercury production there, in Clay Lake, and in Ball Lake. The large quantities of methyl mercury produced between Dryden and Clay Lake are mostly dissolved in water and are swept downstream, elevating concentrations in water and biota throughout the system. Several options for remediating the ongoing contamination are discussed.

The Effect of pH on Methyl Mercury Production and Decomposition in Lake Sediments

1985 ◽  
Vol 42 (4) ◽  
pp. 685-692 ◽  
Author(s):  
P. S. Ramial ◽  
John W. M Rudd ◽  
Akira Furutam ◽  
Luying Xun
Keyword(s):  
Lake Sediments ◽  
Methyl Mercury ◽  
Inorganic Mercury ◽  
Mercury Methylation ◽  
Surficial Sediments ◽  
Experimental Lakes Area ◽  
Effect Of Ph ◽  
Northwestern Ontario ◽  
Acidified Lakes ◽  
Mercury Production

Mercury methylation was measured in surficial sediments taken from unacidified and experimentally acidified lakes in the Experimental Lakes Area, northwestern Ontario. A reduction in the pH of sediments lowered the rate of 203Hg methylation. Methylation was undetectable at pH <5.0. This decrease in mercury methylation was probably related to a shortage of available inorganic mercury when the pH of the sediment porewater was reduced. Below pH 6.0, inorganic mercury concentrations in porewater, measured with 203Hg, were reduced to less than 20% of that found at unaltered pH. A comparison of methylation and demethylation rates was made at various pH's. The rate of demethylation decreased to a lesser extent than methylation as the pH was lowered. This research indicates that enhanced mercury methylation in the sediment is not responsible for the observed increase in mercury levels in fish from acidified lakes.

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