Minimised bioconcentration tests: a useful tool for assessing chemical uptake into terrestrial and aquatic invertebrates?

Laura J. Carter,Jim J. Ryan,Alistair B. A. Boxall,Roman Ashauer

doi:10.1021/es5031992

Abstract

Current guidelines for determining bioconcentration factors (BCF) and uptake and depuration rate constants require labor intensive studies with large numbers of organisms. A minimized approach has recently been proposed for fish BCF studies but its applicability to other taxonomic groups is unknown. In this study, we therefore evaluate the use of the minimized approach for estimating BCF and uptake and depuration rate constants for chemicals in aquatic and terrestrial invertebrates. Data from a range of previous BCF studies were resampled to calculate BCFs and rate constants using the minimized method. The resulting values were then compared to values obtained using full study designs. Results demonstrated a good correlation for uptake rate constants, a poor correlation for depuration rate constants and a very good correlation between the BCFs obtained using the traditional and minimized approach for a variety of organic compounds. The minimized approach therefore has merit in deriving bioconcentration factors and uptake rate constants but may not be appropriate for deriving depuration rate constants for use in, for example, toxico-kinetic toxico-dynamic modeling. The approach uses up to 70% fewer organisms, requires less labor and has lower analytical costs. The minimized design therefore could be a valuable approach for running large multifactorial studies to assess bioconcentration of the plethora of chemicals that occur in the environment into the many taxonomic groups that occur in the environment. The approach should therefore help in accelerating the development of our understanding of factors and processes affecting uptake of chemicals into organisms in the environment.

Highlights

Synthetic chemicals such as pesticides, pharmaceuticals, personal care products, industrial chemicals, and veterinary medicines can reach the environment and accumulate in biota.[1−3] It is important to study the uptake of these chemicals into nontarget organisms because toxic effects may be induced within the organism and there is the potential for them to be accumulated as they move up food chains.[4,5]
For example environmental risk assessment regulations for pesticides, biocides, veterinary medicines, pharmaceuticals and industrial chemicals (e.g., REACH, EU legislation Regulation (EC No 1107/2009),[7] Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA),[8] China REACH9) require bioconcentration factors to be measured and these are typically compared to a threshold to determine whether there is a risk of bioaccumulation or not
Comparison of the rate constants obtained using the minimized (k1 and k2 minimized) and traditional (k1 and k2 traditional) approaches showed that generally there was a good correlation between uptake rate constants obtained using the minimized and traditional approaches, the minimized approach appears to result in smaller predictions than the full approach where uptake rate constants are low (Figure 2a)

Summary

Introduction

Synthetic chemicals such as pesticides, pharmaceuticals, personal care products, industrial chemicals, and veterinary medicines can reach the environment and accumulate in biota.[1−3] It is important to study the uptake of these chemicals into nontarget organisms because toxic effects may be induced within the organism and there is the potential for them to be accumulated as they move up food chains.[4,5] A bioconcentration factor (BCF), which reflects the absorption of a chemical into an organism from the ambient environment through respiratory or dermal surfaces,[2,6] is typically used to describe the accumulation of chemicals within an organism. The rigor of the current guidelines means that large numbers of animals are required and that labor

Methods

Results

Conclusion