Impact/Purpose:

To develop an arsenic speciation protocol for the analysis of dietary seafoods to be used to support fish advisories, improve relative source (water versus diet) contribution for arsenic and provide improved dietary exposure estimates in future epidemiology (EPI) studies.

Description:

The Office of Research and Development has designated the study of arsenic as a high priority research area because of the health risk associated from exposure to this element. Present monitoring efforts are primarily focused on total concentration of arsenic in drinking water. However, because the severity of exposure is related to the chemical form of arsenic, the need to collect speciation data is of prime importance. Because human exposure to arsenic is not limited to drinking water, analytical methods are needed to measure exposure to various species of arsenic from other commonly ingested media such as fish, meat and other edible biota.

One of the major sources of arsenic exposure from the diet is seafood. Although nontoxic arsenicals such as arsenobetaine (AsB) and arsenocholine (AsC) are commonly associated with seafoods, it is inappropriate to assume that seafood exposures are all low risk exposures. The reason for this is two fold. First, while the percentage of toxic arsenicals in seafood can be a relatively low percentage (e.g., <5%) of the total arsenic in the sample, if the sample has an extremely high total arsenic concentration (e.g., 60 parts per million), the toxic dose is then 5% of the 60 ppm total which equals 3 ppm. This dose is small relative to 60 ppm, but it would be considered very significant relative to the proposed 10 parts per billion (ppb) drinking water maximum contaminant level (MCL). The second reason is that toxic forms of arsenic can sometimes exceed 50% of the total arsenic (e.g., 10 ppm) in certain seafoods. This would imply a 5 ppm (50% of 10ppm) exposure which again is significant relative to the proposed 10 ppb drinking water MCL. These exposures, although acute or episodic (for most Midwest Americans), can produce elevated risks for subpopulations with high seafood consumption rates.

The arsenicals associated with seafoods are bound to proteins, fats or cellulose material and for this reason require an extraction from a solid sample prior to separation and detection. The extraction of arsenicals from seafood samples has traditionally used sonication in combination with methanol/water solvents to assure species specific integrity during the extraction. The sonication procedure is time consuming and labor (hands-on) intensive. The objective of this task was to evaluate the Accelerated Solvent Extractor as a semi-automated means to extract arsenicals from seafoods with a secondary objective of developing improved arsenic speciation capabilities in seafoods which could be utilized in developing a preliminary speciation based database for seafoods. This information / capability could then be used to support fish advisories, improve relative source (water versus diet) contribution for arsenic and provide improved dietary exposure estimates in future epidemiology studies.

Record Details:

Record Type:PROJECT

Start Date:09/01/1997

Completion Date:09/01/2002

Record ID: 18292

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Project Information:

Progress :Research under this task is complete. The following presentations and publications resulted from this research effort:

Presentations:

"A Comparison of Extraction Efficiencies in Seafood Matrices Using a Synthetic Stomach and an ASE Extraction Approach with IC-ICP-MS Detection", presented by Patricia Gallagher, Amy Heck, Xinyi Wei, Carol Brockhoff-Schwegel, and J Creed at The Winter Conference on Plasma Spectrochemistry, Lillihammer, Norway, 2/01.

- Accelerated Solvent Extraction of Arsenicals from Seafood Matrices with Ion Chromatography and ICP-MS Detection, Fourth International Conference on Arsenic Exposure and Health Effects, San Diego, CA, 6/00.

- Extraction Techniques for the Removal of Arsenicals from Seafood Exposure Matrices with ICP-MS Detection, Fourth International Symposium on Speciation of Elements in Biological, Environmental and Toxicological Sciences, British Columbia, Canada, 7/00.

- Speciation of Arsenic in Exposure Assessment Matrices, 23rd Annual Conference on Analysis of Pollutants in the Environment, Sponsored by USEPA, Pittsburgh, PA, 5/00.

- Accelerated Solvent Extraction of Arsenicals from Environmental Matrices with Ion Chromatography Separation and ICP-MS Detection, Winter Conference on Plasma Spectrochemistry, Ft. Lauderdale, FL, 1/00.

-Extraction and Identification of Arsenosugars in Commercially Available Seaweeds,IICS, San Jose, Ca, 9/99.

- Accelerated Solvent Extraction of Arsenicals in Seaweed with Ion Chromatographic Separation and ICP-MS Detection, American Chemical Society, Anaheim, CA, 3/99.

- An Evaluation of Accelerated Solvent Extraction as a Semi-Automated Means of Extracting Arsenicals Prior to Speciation Analysis via IC-ICP-MS, European Winter Conference on Plasma Spectrochemistry, Pau, France, 1/99.

- The Extraction and Detection of Arsenicals in Seaweed via Accelerated Solvent Extraction with Ion Chromatography Separation and ICP-MS Detection, European Winter Conference on Plasma Spectrochemistry, Pau, France, 1/99.

- Extraction of Arsenicals from Dietary Fish via Accelerated Solvent Extraction with Ion Chromatographic Separation and ICP-MS Detection, FACSS, Austin, TX, 10/98.

- Development of Arsenic Speciation Data for Fish, Shellfish, Seaweed and Water, 3rd International Conference on Arsenic Exposure and Health Effects, San Diego, CA., 8/98.

- Extraction and Determination of Arsenicals Found in Fish Tissue, Pittsburgh Conference, New Orleans, LA., 3/98.

Publications:

- Gallagher, P., Creed, J.T. Wei, X., Murray S., Brockhoff, C.A., An Evaluation of Sample Dispersion Medias with ASE for the Extraction and Recovery of Arsenicals in LFB and DORM-2 with ICP-MS Detection (2002), Journal of Analytical Atomic Spectrometry, 17(6), 781-785.

- Gallagher, P., Creed, J.T. Wei, X., Shoemaker, J., Brockhoff, C.A., Extraction and Detection of Arsenicals in Seaweed via Accelerated Solvent Extraction with Ion Chromatographic Separation and ICP-MS Detection (2000), Fresenius Journal of Anal. Chem. 369, 71-80.

- Gallagher, P., Creed, J.T. Wei, X., Shoemaker, J., Brockhoff, C.A., Detection of Arsenosugars from Kelp Extracts via IC-ESI-MS/MS and IC Membrane Hydride Generation ICP-MS (1999), Journal of Analytical Atomic Spectrometry, 14, 1829-1834.

- McKeirnan, J., Brockhoff, C.A., Creed, J.T., Caruso, J. (1999) A Comparison of Automated and Traditional Methods for the Extraction of Arsenicals from Fish, Journal of Analytical Atomic Spectrometry, 14, 607-613.

This task was conducted in collaboration with Region 10 and one of the goals of this project was to transfer capabilities developed under this task to the Region 10 laboratory. This was accomplished via a series of visits to Region 10 through FY02.



Relevance :Relevance : The Office of Research and Development (ORD) has designated the study of arsenic as a high priority research area because of the health risk associated from exposure. Furthermore, ORD's Arsenic Research Plan identifies improved analytical capabilities in dietary matrices as a key area in reducing the uncertainty in the arsenic risk assessment. The National Research Council report concluded that dietary exposure was a source of uncertainty in arsenic exposure assessment and would improve future EPI studies. Similar conclusions were made in a recent American Water Works Association Research Foundation report. The research described in this task is relevant and aligned with research priorities rankings identified by these independent review panels. Significance: Human exposure to arsenic is not limited to drinking water. Therefore, arsenic exposure estimates from dietary sources is essential in formulating relative source contribution (RSC) estimates. Improved data will minimize the error associated with using a default assumption for this estimate. In addition, the dietary exposure component of EPI studies have been largely overlooked because of a lack of analytical capability to estimate the exposure to arsenic from dietary ingestion. Improved EPI studies and improved dietary exposure estimates will provide the scientific data necessary to assess a revised drinking water MCL for arsenic. The methods and data generated under this task also provide information which aids in identifying highly exposed sub-populations. Finally, this data is useful in supporting fish advisories and the FDA's Food Safety Protection Act. Impact: Improved dietary exposure data in key food groups will provide improved relative source estimates and added capabilities to assess the dietary influence in future EPI studies. Improved dietary exposure assessment for arsenic may reduce the RSC estimate and in turn influence the allowable drinking water exposures in the future. Likewise, if existing RSC estimates are low the improved data may reduce the allowable drinking water exposure in the future. Collaborations and Client Interaction: This project has been a collaboration between NERL and Region 10. The object has been to develop the analytical capability in NERL and transfer this technology to the Region 10 laboratory so that accurate exposure estimates could be obtained for coastal populations in which seafood consumption is high. NERL scientists and Region 10 scientists have conducted periodic teleconferences and NERL scientists have visited the Region 10 laboratory approximately once per year since the inception of this task to facilitate the technology transfer. A final visit is planned for FY02.

Clients :Region 10 (Contact - Roseanna Lorenzana, Isa Chamberlain)

Research Component :ARSENIC

Risk Paradigm :EXPOSURE

Project IDs:

ID Code :none

Project type :ORD-DW Plan

ID Code :4030

Project type :OMIS