The Use of Direct Toxicity Assessment in The Assessment and Control of Complex Effluents in The UK: A Demonstration Programme

Abstract

This paper outlines the background, objectives, methodology, findings, outputs and recommendations from the Direct Toxicity Assessment (DTA) Demonstration Programme. This was a trial of a suite of bioassay methods and a seven-step protocol designed to deliver water quality improvements in catchments with well-defined water quality problems, where ecotoxicity from effluents was a contributing factor. The trial was run as a collaborative venture between the environmental regulators and water and manufacturing industries in the UK and was conducted at three project sites: -a reach of the river Aire near the city of Bradford in Yorkshire; -a reach of the River Esk near the town of Langholm on the border between Scotland and England; and -the lower Tees estuary on the north-east coast of England. The outcomes of each project are summarised in this paper. The learning points delivered by the programme were used to make recommendations to the regulators on how best to use bioassays for the assessment and control of complex effluents in the UK. Guidance was provided on how to carry out the bioassays and on how to use the data generated for regulatory decision-making. The programme also demonstrated how the regulators and the regulated can successfully work together to tackle environmental issues and deliver effective and workable solutions.

Ecotoxicological assessment of effluents in the Basque country (Northern Spain) by acute and chronic toxicity tests using Daphnia magna straus

“…Based on the results of this study and on other experiences, such as the whole-effluent assessment used in Direct Toxicity Assessment (DTA) in the UK (Tinsley et al 2004), we propose a ''step-wise'' protocol for the assessment of industrial and municipal effluents in Spain, and in particular in the Basque Country. First, a broad screening with simple pass/fail tests will help to perform a rapid preliminary distinction between NonToxic versus Toxic effluents, facilitating the rapid identification of ecotoxicity hotspots in the country and the establishment of priority actions.…”

Chemical, biological, and ecotoxicological assessment of pesticides and persistent organic pollutants in the Bahlui River, Romania

“…Regarding ecotoxicological testing, whole effluent toxicity tests may provide a basis for more in-depth investigations, like toxicity identification evaluations to identify the particular toxic components in municipal and industrial effluents, and the detailed toxicological effects important for water quality management (e.g., Tinsley et al 2004). Also, the battery of toxicity tests used in this study was rather limited and should be extended during future investigations.…”

The relationship between whole effluent toxicity (WET) and chemical-based effluent quality assessment in Vojvodina (Serbia)

“…By using an in situ bioassessment approach, Maltby et al (2000) demonstrated receiving water toxicity and ecological degradation that were consistent with the results of WET tests performed on the point source discharge and concluded that systematic approach provides a comprehensive and ecologically relevant database for assessing the ecological risk posed by point source discharges, so that by applying a set of complementary diagnostic tools, resource managers and dischargers would gain greater confidence in the permit limits set for effluents and the methods used to monitor compliance. Quite a large number of specific research studies of ecotoxicity of industrial effluents using conventional toxicity tests combined with chemical quality assessment, were conducted world-wide, such as, for instance, in Portugal (Mendonca et al 2007), Spain (Rodriguez et al 2006), UK (Tinsley et al 2004), Italy (Guerra 2001), Netherlands (Tonkes et al 1999), Turkey (Sponza 2002), Lithuania and Estonia (Manusadzianas et al 2003), Argentina (Gomez et al 2001;Di Marzio et al 2005), Brasil (Araujo et al 2005) and South Korea (Ra et al 2006a). The conclusion from all the cited studies, which stands for our research as well, is that clear environmental benefit can be delivered by targeting the use of effluent bioassays at catchments with well defined water quality problems, where ecotoxicity from complex effluents is expected to be a contributing factor, despite compliance with chemical limits.…”