International trends in bioassay use for effluent management.

The use of effluent bioassays in various international jurisdictions is reviewed, resulting in an analysis of themes and trends in: regulatory use, different uses of bioassays in meeting protection goals, different types of bioassays, bioassay test variability, statistical design, use of effluent bioassays to predict receiving environment effects, and uptake of effluent bioassay testing by developing countries. Current effluent bioassay use by jurisdictions in North America, the European Union, and Asia/Pacific is described. The historical trend for many jurisdictions has been to start with chemical hazard-based systems, then add effluent bioassays (first lethal, then sublethal measures) and then use receiving environment evaluations to predict or measure impacts. For jurisdictions adopting effluent bioassays over the past decade, policies about the use of in vivo vertebrate tests appear to be influencing the types of bioassays that are used and there is also a trend towards micro-scale tests. In countries where regulations relating to effluent management do not require effluent bioassays, uptake of bioassays is relatively slow. Good practice for effluent bioassay applications can only be defined with regard to the regulatory regime, as differences between jurisdictions (e.g., hazard-based versus risk-based regimes, policies on in vivo vertebrate testing) will result in different choices.

Temporal and spatial trends of PCB congeners in UK gannet eggs.

Gannet (Sula bassana) eggs collected from Ailsa Craig, Western Scotland between 1977-1998 have been analyzed retrospectively for several PCB congeners. Concentrations of a range of congeners were determined in 8-10 eggs analyzed separately for several individual years. All congeners declined in concentrations throughout the time period, but the rates of decline differed for different congeners. Declines were first order and half-lives varied between 5.4 years for PCB-101 to 10.1 years for PCB-180. Egg concentrations reflect the maternal body burden, which itself is controlled by the birds rate of intake (principally via the diet) and losses (via metabolism and other clearance mechanisms). The declining concentrations in eggs, therefore, broadly reflect reductions in prey concentrations (principally herring and mackerel) and--in turn--water column concentrations. Rates of change in PCB concentrations from this study were similar to those noted in fish-eating birds from the Baltic Sea and North American Great Lakes, and ambient air in the UK. This provides indirect evidence that gannet eggs are broadly reflecting regional/global scale clearance/removal mechanisms which are controlling ambient PCB concentrations.