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Validation and Extension of a Rapid Method of Dioxin Screening in Marine and Freshwater Fish through Multivariate Statistical Analysis of Fatty Acid Profiles
Impact/Purpose:
We are proposing validation and extension of the ‘Bassompierre’ method to freshwater whole fish of three trophic levels (i.e. predators, benthic and forage fish) collected by Region III from the Kanawha River, which has high dioxin levels from dumping of Agent Orange following the Vietnam war. The novel Bassompierre fatty acid profile method may provide stakeholders (i.e., federal, state, tribal, non-profit and commercial laboratories) with a high throughput screening technique for determining dioxin TEQ-WHO values in freshwater fish tissue samples. Once this method is operational those samples identified as likely to exceed a TEQ-WHO threshold of concern, for either ecological or human health risk, could then have confirmatory analysis performed using Method 1613.
Description:
Over 95% of human exposure to dioxin is through ingestion of animal fats. Studies have identified both freshwater and marine fish, from wild and farmed stocks, as a significant source of human exposure to dioxins (Alcock and others 1998; Turyk and others, in press; Rawn and others 2006; Bocio and Domingo 2005). Dioxin levels in fish tissue have lead to consumption advisories in North America and Europe, for both farmed and wild fish (SCAN 2000; USEPA 2004c). Dioxins (and furans) in fish tissue are presently determined to the low parts per trillion range by EPA Method 1613 (USEPA 1994; 1997a; 1997b). This method is a high resolution (HR) GC/MS method which is very costly (~$600-$850 per biological sample at a commercial lab), time consuming (an analytical turn-around-time of 35 days, not including time for data validation, which takes a month, under ideal conditions), and creates potentially hazardous waste, all of which limit its applicability. Method 1613 starts with a solvent extraction of 10 grams of tissue sample followed by several cleanup procedures to isolate the 2,3,7,8-dioxin/furan congeners. After cleanup, the solvent extract is analyzed for the usual 17 dioxin/furan congeners using HRGC/HRMS. Recently, Danish researchers (Bassompierre and others 2004a; 2004b) have reported a rapid method of dioxin screening of North Atlantic saltwater fishmeal utilizing multivariate statistical analysis (Principal Components Analysis - PCA and Partial Least Squares Regression - PLS) of the multivariate covariance between dioxin WHO-TEQ toxicity and fatty acid profiles. GC-FID (Gas Chromatography – Flame Ionization Detection) analysis determined fatty acid profiles.