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BEAUDIN, L., S.C. JOHANNESSEN, R.W. MACDONALD, 2010. spectrophotometry : an example using mercury analysis of small sections of fish scales. Anal. Chem. (Wash.), 82(21): 8785-8788 .
Mercury is a toxic element that exchanges among air, water, and sediments and biomagnifies into high trophic level organisms. Here, we present a novel combination of laser ablation with relatively low-cost cold vapor atomic fluorescence spectrophotometry to analyze Hg vaporized from targeted patches of fish scale 300–500 μm square. This method permits the analysis of multiple samples from the same scale, which is useful, because fish scale growth rings may provide an archive from which spatial and temporal trends in environmental Hg can be inferred at fine resolution. The detection limit of the method is 1.5 pg Hg, with a precision of 0.1 pg/μL. Developed using fish scales, the method could be adapted to other media, such as baleen, shells, nails, hair, teeth, wood and, possibly, varved sediments.©2010 American Chemical Society
GALLON, C., A. TESSIER, C. GOBEIL, L. BEAUDIN, 2005. Sources and chronology of atmospheric lead deposition to a Canadian Shield lake : inferences from Pb isotopes and PAH profiles. Geochim. Cosmochim. Acta, 69(13): 3199-3210 .
The depth-distribution of lead and its stable isotope ratios were determined in a dated sediment core from a Canadian Shield lake receiving anthropogenic Pb inputs exclusively from atmospheric deposition. The results demonstrate that anthropogenic Pb deposited to the sediments of this lake since the preindustrial period can be modeled successfully using as little as two isotopically distinct Pb types. The first, whose flux was not detectable before 1850, reached a maximum value around 1950, and then decreased significantly thereafter; it was characterized by 206Pb/207Pb and 206Pb/208Pb ratios of 1.222 and 0.495, respectively, and was derived mainly from coal combustion. The second, whose flux was not detectable before 1880, increased sharply to exceed that of the Pb type derived from coal combustion around 1930, and reached a maximum in the mid 1970s; it is characterized by 206Pb/207Pb and 206Pb/208Pb ratios of 1.179 and 0.482, respectively, and was derived mainly from leaded gasoline combustion and industrial sources. The chronology of deposition of these two anthropogenic lead types agrees well with the historical records of fossil fuel uses in Canada and the USA, and also with the history of sediment-deposited polycyclic aromatic hydrocarbons (PAHs) originating from coal combustion. The inventory of Pb derived from coal combustion (0.09 αmol cm-2) is ˜30 % of that derived mainly, but not exclusively, from leaded gasoline (0.31 αmol cm-2). Apportionment among source regions of lead deposited to the sediments during the period when leaded gasoline dominated Pb atmospheric emissions indicates that &tilde: 50 % of this lead originated in the USA.©2005 Elsevier Ltd
GOBEIL, C., B. RONDEAU, L. BEAUDIN, 2005. Contribution of municipal effluents to metal fluxes in the St. Lawrence River. Environ. Sci. Technol., 39(2): 456-464 .
The contribution of urban effluents to the total metal fluxes carried toward the sea by the St. Lawrence, a major world river, is 60 % for Ag; 8-13 % for Cu, Zn, Mo, Cd, and Bi; and less than 3 % for all other measured elements (Al, V, Cr, Mn, Fe Co, Ni, As, Rb, Sr, Zr, Cs, Ba, W, Re, Pb, Th, U). This is inferred from measurements at the Montreal wastewater treatment plant. Except for Ag, municipal effluents do not weigh heavily on the St. Lawrence River metal budget, likely because of the physical-chemical primary treatment applied to most effluents. Compared to direct atmospheric deposition on the surface of the river, effluents would contribute half as much Pb and one-tenth as much Zn. In contrast, effluents deliver twice as much Cd and six times as much Cu as the atmosphere. Stable Pb isotope ratios (206Pb/207Pb, 206Pb/208Pb) in suspended particulate matter from the river indicate that the total Pb content in the river water is three times higher than the pristine level. The ratios of Cr, Ni, Cu, Zn, and Cd to Al in suspended particulate matter are high as compared to pre-industrial sediments, which suggests that trace element fluxes are higher today. To decrease metal levels in the St. Lawrence River further will be a challenge since the sources of metals are not well-known.©2005 American Chemical Society
GOBEIL, C., R.W. MACDONALD, J.N. SMITH, L. BEAUDIN, 2001. Atlantic water flow pathways revealed by lead contamination in Arctic Basin sediments. Science (Wash.), 293: 1301-1304 .
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