Determination of Mercury Speciation in Fish Tissue with a Direct Mercury Analyzer
Oral Presentation
Prepared by B. Barst1, P. Drevnick2
1 - INRS-ETE, 490 de la couronne, Quebec, Quebec, G1K9A9, Canada
2 - University of Michigan Biological Station and School of Natural Resources and Environment, Dana Building G168, Ann Arbor, Michigan, 48109, United States
Contact Information: [email protected]; 418-657-3554
ABSTRACT
Knowledge of mercury speciation in tissue is valuable for assessing potential toxicological effects in fish. Direct mercury analyzers have recently gained popularity for determining organic mercury after procedural solvent extraction from some environmental media, although quantitative recovery from lipid-rich materials, such as fish liver, has been problematic. We developed a new method by which organic mercury in fish liver and muscle is estimated by difference from direct measurements of inorganic mercury in an acid extract and total mercury in whole tissue. The method was validated by analysis of a certified reference material (DOLT-4) and naturally contaminated fish tissues with comparison to an established mercury speciation method (GC-CVAFS). Recovery of organic mercury from DOLT-4, estimated by difference, averaged 99± 5% of the mean certified value for methylmercury. In the majority of liver samples and all muscle samples, estimates of organic mercury from the proposed method were indiscernible from direct speciation measurements of methylmercury (99± 6%). Estimation of organic mercury by difference between total mercury and inorganic mercury was less accurate in liver samples with high percent inorganic mercury (90%). This was due to the increased uncertainty that results from estimating a third value (i.e., organic mercury) by difference between two large concentrations (inorganic mercury and total mercury). The proposed method is a useful tool for examining the speciation of mercury in fish muscle and liver, and by extension, potentially other tissues and environmental media. Potential applications of this method will be discussed.
Oral Presentation
Prepared by B. Barst1, P. Drevnick2
1 - INRS-ETE, 490 de la couronne, Quebec, Quebec, G1K9A9, Canada
2 - University of Michigan Biological Station and School of Natural Resources and Environment, Dana Building G168, Ann Arbor, Michigan, 48109, United States
Contact Information: [email protected]; 418-657-3554
ABSTRACT
Knowledge of mercury speciation in tissue is valuable for assessing potential toxicological effects in fish. Direct mercury analyzers have recently gained popularity for determining organic mercury after procedural solvent extraction from some environmental media, although quantitative recovery from lipid-rich materials, such as fish liver, has been problematic. We developed a new method by which organic mercury in fish liver and muscle is estimated by difference from direct measurements of inorganic mercury in an acid extract and total mercury in whole tissue. The method was validated by analysis of a certified reference material (DOLT-4) and naturally contaminated fish tissues with comparison to an established mercury speciation method (GC-CVAFS). Recovery of organic mercury from DOLT-4, estimated by difference, averaged 99± 5% of the mean certified value for methylmercury. In the majority of liver samples and all muscle samples, estimates of organic mercury from the proposed method were indiscernible from direct speciation measurements of methylmercury (99± 6%). Estimation of organic mercury by difference between total mercury and inorganic mercury was less accurate in liver samples with high percent inorganic mercury (90%). This was due to the increased uncertainty that results from estimating a third value (i.e., organic mercury) by difference between two large concentrations (inorganic mercury and total mercury). The proposed method is a useful tool for examining the speciation of mercury in fish muscle and liver, and by extension, potentially other tissues and environmental media. Potential applications of this method will be discussed.
