Impact/Purpose:

Mercury is a bioaccumulative toxin that moves from placer gold mines. PMD is conducting a literature search for new methods of measuring mercury and methyl mercury in fish tissue and the livers of fish eating birds. to achieve very low values. This information will lead to use of better methods for determining current levels of total mercury in the birds and fish of the Carson River Watershed.

Description:

This project involves conducting a literature search with the goal of identifying "robust" methods for measuring mercury concentrations in biological tissues. Mercury is a significant contaminant of concern in Region 9, due in large part to the extensive mining activities of the last century and a half. Ongoing investigations of mercury and its environmental effects, such as those being conducted by EPA's Superfund Division along the Carson River in Nevada, require sensitive and accurate methods for measuring mercury in a wide variety of media, including biological tissues. As inorganic mercury makes its way into the food chain, it becomes incorporated into a variety of organic compounds. Methods commonly used to measure mercury in soil, sediment, and water can usually detect the inorganic forms present in the soil, sediment, or water sample. However, these methods may not detect all the organic forms of mercury present. This can be especially problematic if these methods are used to measure mercury in biological tissues such as liver, blood, bird eggs, and insects, where the majority of the mercury is present in organic forms. The goal of this project is to identify analytical methods in the literature which have been developed to accurately measure mercury in tissues. It would be most helpful to find methods and techniques which have proven "successful." But it would also be useful to have information about the effectiveness of all the approaches that have been evaluated and reported in the literature, so that the "unsuccessful" ones can be avoided. Several literature data bases and indexing services are available, and are accessible from desktop personal computers. A secondary task might be to locate commercially-available sources of tissues in which the mercury concentration has been accurately measured by the most accurate techniques available. These "Certified Reference Materials" (so-called because the material is "certified" to contain mercury at the concentration stated on the accompanying certificate) are important tools used by environmental laboratories to assess the accuracy of their methods.

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