Superfund Research Program
Trace Elements Analysis Core
The goal of this core remains the same as specified in the grant, i.e., to provide state-of-the-art analysis for low level metal detection and speciation in support of the projects of this program, principally Project 4 (epidemiology), Project 6 (geochemistry) and Project 7 (ecotoxicology) in which low level detection and speciation of specific toxic metals is crucial to the success of those research projects. The development of mercury speciation methods applying GC-ICPMS has been completed and the core now has two different methods running on a routine basis in the laboratory. A standard GC-ICPMS method for mercury speciation (Hg2+ and MeHg+) in fish and larger zoo-plankton samples (> 200 mg). The other method is for small or low-concentration samples (most often zoo-plankton) utilizing a purge-and-trap system for pre-concentration of mercury species, this system is unique and column heaters were build in the laboratory as no such system is commercially available. Both methods are in the process of being published, the first paper already being submitted for publication in Journal of Analytical Atomic Spectroscopy. The developed mercury speciation methods are now being used for the analysis of fish and zoo-plankton samples from the ecotoxicology research project (project 7; Carol Folt and Celia Chen). In 2004 with a skilled ICPMS technician (Ms. Angela LaCroix-Fralish) and the Agilent 7500c ICPMS instrument running many different samples types and routine methods in addition to being used for arsenic and mercury speciation with the Element I ICPMS instrument being used exclusively for total mercury determinations, the core was able to significantly increase their sample throughput and exceeded their goal of 6000 samples per year and has completely cut back on all of the backlogged samples. In the fall of 2004 another milestone was reached, the implementation of a new laboratory information system developed especially for the Dartmouth College Core Facilities. This system allows the core to keep track of all samples entering the laboratory and all results sent out in addition to keeping track of expenses, income and invoices. This system now allows the team to plan the work in the laboratory more efficiently and save themselves a lot of time in addition. Core B is vital to the success of the entire program, which is based on the low level detection of trace toxic elements and their speciation. Recent research findings, particularly in the case of arsenic and mercury, reiterate the importance of not only being able to accurately quantify low levels of metals, but also having the ability to speciate. It is now clear that different species (valence, ligand partners) of each metal can have vastly different chemical and biological properties. Dartmouth has a state-of-the-art ICP-MS facility capable of providing these data, and also has the technical expertise to assist researchers in the design and analysis of their experiments so that they obtain accurate information and glean the most insights possible from their studies. This support core allows projects such as Projects 4, 6 and 7 to remain on the cutting edge of their fields. Core B will continue to provide state-of-the-art technical support for this research program. They plan to continue their ongoing support, as well as to develop new methodologies that will be most useful and tailored to each project’s research needs so that the projects can achieve their scientific goals.