September 7, 2012 by Adam Peters

Earlier this summer I had the opportunity to attend the second Aquatic Toxicology Symposium. This is a small and informal meeting where various research leaders in the relevant area meet up to discuss their findings. The first ATS was held at a former borax mine in Arizona, and in keeping with the theme this meeting was held at a former copper mine in the Cascade mountains in Washington state. The mine has been closed for over 50 years, but the former miners village is now run as a retreat by the Lutheran church. The former mine workings are currently undergoing a remediation programme to prevent impacts from the mine on the river and to stabilise old tailings piles. Recent surveys have shown some effects of the mine on aquatic communities in the river close to the tailings piles, and these should be reversed by the remediation works.

The theme of this workshop was the use of bioassessment for characterizing the impacts of metals on stream benthos and fish. This is an area that I have been working on with colleagues at wca for several years, particularly for the purpose of deriving or validating Environmental Quality Standards. The workshop was an excellent opportunity to discuss findings with other leading researchers in the field, and it was particularly encouraging to find that many of us had been faced with relatively similar problems, and that there was a surprising degree of consistency to the findings of studies conducted in different parts of the world. There are many potential problems to be addressed when studying effects in the field, such as exposures to mixtures of contaminants, the variability of aquatic communities in relatively similar streams, and the importance of other factors which might affect the local aquatic communities (e.g. flow and habitat conditions).

I hope to be able to make use of some of what I learnt at this workshop in our efforts towards EQS derivation and validation in the future, although there is still a great deal that we have yet to learn about how aquatic communities respond to different kinds of pressures. An increase in the use of ecological quality assessments in Europe as a result of the Water Framework Directive is likely to improve our understanding of some of these issues in the future.