Does bisphenol a induce superfeminization in Marisa cornuarietis? Part I: Intra- and inter-laboratory variability in test endpoints

Valery E. Forbes1*, Henriette Selck1, Annemette Palmqvist1, John Aufderheide2, Ryan Warbritton2, Nadine Pounds3, Roy Thompson3, Nelly van der Hoeven4, Norbert Caspers5

1 Department of Environmental, Social and Spatial Change, Roskilde University, Universitetsvej 1, PO Box 260, 4000 Roskilde, Denmark
2 ABC Laboratories, Inc., 7200 E. ABC Lane, Columbia, MO 65202, USA
3 Brixham Environmental Laboratory, AstraZeneca UK Limited, Freshwater Quarry, Devon TQ5 8BA, UK
4 ECOSTAT, Vondellaan 23, 2332 AA, Leiden, The Netherlands
5 Bayer Industry Services, D-51368 Leverkusen, Germany

Corresponding Author:

Valery Forbes
Department of Environmental, Social and Spatial Change,
Roskilde University
Universitetsvej 1,
PO Box 260,
4000 Roskilde,
Denmark
fax: (+)31-45 46 74 30 31;
email: vforbes@iruc.dk

Summary

It has been claimed that bisphenol A (BPA) induces superfeminization in the freshwater gastropod, Marisa cornuarietis. To explore the reproducibility of prior work, here we present results from a three-laboratory study, the objectives of which were to determine the mean and variability in test endpoints (i.e., adult fecundity, egg hatchability, and juvenile growth) under baseline conditions and to identify the sources of variability. A major source of variability for all of the measured endpoints was due to differences within and among individuals. With few exceptions, variability among laboratories and among replicate tanks within laboratories contributed little to the observed variability in endpoints. The results highlight the importance of obtaining basic knowledge of husbandry requirements and baseline information on life-history traits of potential test species prior to designing toxicity test protocols. Understanding of the levels and sources of endpoint variability is essential so that statistically robust and ecologically relevant tests of chemicals can be conducted.

keywords: Endocrine disruption; Gastropod; Reproduction; Risk assessment; Test design

logo ECOSTAT Ecotoxicol. Environm. Safety, 66: 309-318, 2007