Cattle Tissue Sampling and Analysis for Use in Multiple Pathway Risk Assessment of PCDDs, PCDFs. T. L. Copeland and R. H. Pesin, Harding Lawson Associates, 3 Hutton Centre Drive, Santa Ana, CA 92707
Multiple pathway exposure models that predict the uptake of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) into various components of the food chain (e.g., beef and dairy cattle) have been widely applied to predict potential health risks. Because these models are based on steady state assumptions and limited sampling data, there is considerable uncertainty in their results. One approach to reducing uncertainty in the characterization of chemical uptake is to directly measure chemical concentrations in the specific media (e.g., cattle tissue). This study presents a comprehensive sampling and analysis protocol for the evaluation of PCDDs and PCDFs in beef cattle that graze adjacent to an incinerator. Samples of muscle and fat were obtained from four female cows at slaughter and analyzed for PCDDs and PCDFs by Triangle Laboratories using EPA Test Method 8290 to meet detection limit targets for these compounds. Results of the analysis were compared to the results of risk assessment models and to background concentrations published by EPA.