MP11 Advances in Bioaccumulation Assessment
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(SPR-1117-831492) A Modified Approach to Aquatic Bioconcentration Factor (BCF) Tests Using Reduced Sampling.

Springer, T¹, Krueger, H¹, Jaber, M¹, Guiney, P², ¹ Wildlife International, Ltd., Easton, MD, USA² S.C. Johnson & Sons, Inc., Racine, WI, USA

ABSTRACT- Recent regulatory initiatives have created a need for more efficient methods for estimating the bioconcentration factor (BCF) of chemicals in fish. We present simulation and study results demonstrating that BCF estimates can be made reliably using an approach that reduces study complexity, analytical costs, and animal use compared to standard bioconcentration tests. The modified test is similar in some respects to standard designs. However, tissue samples are taken only during the depuration period, and at only two or three points in time. The approach is focused on estimating the BCF using the kinetic definition (i.e. BCF = K_uptake/K_depuration) and does not require that chemical concentrations in water and tissue are at equilibrium. The performance of the modified test design was assessed by comparing BCF estimates obtained in a series of standard guideline tests to BCF estimates that would have been obtained had the study been performed using the modified approach. Modified test results were estimated by resampling from the uptake and depuration data. Data was drawn from eight full bioconcentration studies performed in three different laboratories, using a total of 19 bioconcentration curves (multiple curves for nonedible, edible, whole fish portions and different concentrations). BCF estimates based on the curves studied ranged from about 0.3 to over 20,000. The correlation between log (BCF) estimates from the modified test and log (BCF) estimated from the full data set analyzed using the standard approach was R² = 0.99825 with slope = 0.97561. Subsequently, a study was performed using the modified study design. The BCF value determined using the modified kinetic method was nearly identical to the standard BCF value determineded from the ratio of the peak concentration of the chemical in tissue to the concentration of the chemical in the water (i.e. assuming equilibrium), suggesting that both BCF estimates were reasonable. The available evidence suggest that the modified kinetic approach offers significant advantages over standard BCF tests in use of resources with little sacrifice in precision and predictive power.

Key words: bioconcentration factor, bioaccumulation, fish, BCF