T10 PM Advances in Bioaccumulation Assessment
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 341-342

(WOO-1117-631936) BCF data analysis techniques: What are the most effective and efficient tools?

Woodburn, K¹, ¹ The Dow Chemical Company, Midland, MI, USA

ABSTRACT- Bioconcentration studies provide critical information for both aquatic and terrestrial risk assessments to evaluate the impacts of chemicals on wildlife species and potentially for uptake into human consumers. A key parameter resulting from such experiments is the bioconcentration factor or BCF value, and this value is ideally evaluated at steady-state conditions or using toxicokinetic parameters. The former situation may be unrealistic for many highly lipophilic materials which can require extremely long exposure timeframes for achievement of steady-state conditions. Pharmacokinetic modeling techniques can allow kinetic parameter estimation over shorter periods of time and provide insight into the key issues of absorption, distribution, and metabolism. A current regulatory guideline BCF study with fish typically requires a 28-day water exposure under flow-through conditions, followed by a minimum 14-day clearance period. Data on BCF values generated via empirical steady-state conditions will be compared to kinetic parameter-estimated BCFs. An additional issue that will be examined is the relative importance of dosimetry in bioconcentration studies. Current regulatory guidelines require two separate exposure concentration studies, differing in dose by a factor of ten; these studies are time, money, and animal intensive. Bioconcentration data will be examined as to whether the use of such dual exposure experiments is warranted, or if alternatives exist requiring less intensive use of animals with an acceptable level of accuracy. Supporting examples taken from case studies will be presented and discussed. All statistical analyses involve a comparison of means using the paired t-test.

Key words: bioconcentration, steady-state, pharmacokinetic, dosimetry