Mercury lake studies

Hudson RJM, Gherini SA, Watras CJ, Porcella DB. 1994. Modeling the biogeochemical cycle of mercury in lakes the Mercury Cycling Model (MCM) and its application to the MTL study lakes. In Watras CJ, Huckabee JW, editors. Mercury pollution integration and synthesis. Boca Raton (FL) Lewis Publishers, CRC Press Inc., p. 473-523. 

Driscoll et al. (1994) have studied the mercury species relationships among water, sediments, and fish (yellow perch) in a series of Adirondack lakes in New York state, USA. In most lakes, approximately 10% of the total mercury loading was in the form of C2HsHg+. Mercury concentrations increased as pH fell, but the best correlation was found between [dissolved Al] and [dissolved Hg] suggesting that the same factors are responsible for mobilizing both these metals. Methylmercury concentrations correlated strongly with the dissolved organic carbon content in the water. Fish muscle tissue was analyzed for mercury and showed an increase with age. However, the study was unable to resolve the question of whether the principal source of mercury to these lakes was atmospheric deposition or dissolution from bedrock due to acid rains. 

In studies of the concentrations of arsenic, bromine, chromium, copper, mercury, lead and zinc in south-eastern Lake Michigan, it was shown that these elements concentrated near the sediment water interface of the fine-grained sediments. The concentration of these elements was related to the amount of organic carbon present in the sediments (161). However, it was not possible to correlate the concentration of boron, berylium, copper, lanthanum, nickel, scandium and vanadium with organic carbon levels. The difficulty in predicting the behaviour of cations in freshwater is exemplified in this study for there is no apparent reason immediately obvious why chromium and copper on the one hand and cobalt and nickel on the other exhibit such variations. However, it must be presumed that lanthanium might typify the behaviour of the trivalent actinides and tetravalent plutonium. 

A study of mercury in Lake Michigan found levels near 1.6 pM (1.6 X 10 12 M), which is two orders of magnitude below concentrations observed in many earlier studies.5 Previous investigators apparently unknowingly contaminated their samples. A study of handling techniques for the analysis of lead in rivers investigated variations in sample collection, sample containers, protection during transportation from the field to the lab, filtration techniques, chemical preservatives, and preconcentration procedures.6 Each individual step that deviated from best practice doubled the apparent concentration of lead in stream water. Clean rooms with filtered air supplies are essential in trace analysis. Even with the best precautions, the precision of trace analysis becomes poorer as the concentration of analyte decreases (Box 5-2). 

Lakewide Hg Accumulation. Mercury accumulation rates can be calculated for individual core sites as the product of the 210Pb-based sediment accumulation rate and Hg concentration in different strata. If enough cores are analyzed, whole-lake Hg inputs can be calculated by weighting the Hg flux of each core by the portion of the depositional basin it represents. In this study we calculate Hg loading for each lake on an areal basis for two time-stratigraphic units—modem (roughly the last decade) and preindustrial (before 1850)—according to eq 2 ... 

Partly because of this concern, the Wisconsin Department of Natural Resources, in cooperation with the Electric Power Research Institute, initiated an extensive study of Hg cycling in seepage lakes of north-central Wisconsin (14). The mercury in temperate lakes (MTL) study used clean sampling and subnanogram analytical techniques for trace metals (10, 17) to quantify Hg in various lake compartments (gaseous phase, dissolved lake water, seston, sediment, and biota) and to estimate major Hg fluxes (atmospheric inputs, volatilization, incorporation into seston, sedimentation, and sediment release) in seven seepage lake systems. 

Castner, Hamilton Young — (Sep. 11, 1858, Brooklyn, New York, USA - Oct. 11,1899, Saranac Lake, New York, USA) Castner studied at the Brooklyn Polytechnic Institute and at the School of Mines of Columbia University. He started as an analytical chemist, however, later he devoted himself to the design and the improvement of industrial chemical processes. He worked on the production of charcoal, and it led him to investigate the Devilles aluminum process. He discovered an efficient way to produce sodium in 1886 which made also the production of aluminum much cheaper. He could make aluminum on a substantial industrial scale at the Oldbury plant of The Aluminium Company Limited founded in England. However, - Hall and - Heroult invented their electrochemical process which could manufacture aluminum at an even lower price, and the chemical process became obsolete. Castner also started to use electricity, which became available and cheap after the invention of the dynamo by - Siemens in 1866, and elaborated the - chlor-alkali electrolysis process by using a mercury cathode. Since Karl Kellner (1851-1905) also patented an almost identical procedure, the process became known as Castner-Kellner process. Cast-... 

One of the most important problems in oceanography and water resources science is the effect of the concentrations and concentration changes of trace metal ions on the nature of the water system (1-6). Recently, there has been much interest in the apparent increased concentration of metal ions such as mercury, lead, and iron. This concern is, at best, speculative since there are insuflBcient analytical techniques to establish baseline normal concentrations with the precision expected of good analytical methods. For example, there has been tremendous publicity concerning the level of mercury concentrations in edible fish in Lake St. Clair (7, 8, 9). Even in extreme cases, there was considerable disagreement in the true mercury concentrations in the fish analyzed. Rottschafer, Jones, and Mark (9) conducted a comparative study in which a homogenous sample of Coho salmon flesh was dis-... 

Regnell O, Tunlid A. 1991. Laboratory study of chemical speciation of mercury in lake sediment and water under aerobic and anaerobic conditions. Appl Environ Microbiol 57(3) 789-795. 

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