November 30, 2020 by Adam Peters

The SETAC North America meeting has been held as a virtual conference recently (SciCon2) and Adam co-chaired a session with Chris Mebane of the USGS on the derivation and use of Water Quality Criteria, which are equivalent to the Environmental Quality Standards that are set in Europe. All of the presentations in the session were available on-line for at least a week prior to the opening of the conference to give attendees a good opportunity to view the information that was being presented, and questions could be asked about the presentations, and responded to by the presenters, via a messaging system. A key part of the virtual conference is that live discussion sessions were held using videoconferencing to give presenters and attendees an opportunity to discuss some of the broader issues surrounding the session topics. The discussion session was structured around a series of questions that were intended to cover a broad range of issues including substance prioritisation, data evaluation, dataset adequacy, ecological relevance, field evidence, and implementation.

The discussion was interesting and informative and involved several key contributors from the USEPA who were happy to provide their views. Some of the issues that got discussed in particular were the relevance of criteria to specific sites, ecosystems or ecoregions, and the use of higher tier data such as mesocosms and field evidence. An important issue raised was the frequency of review of the criteria once they are set, (apparently some of the US criteria are now over 40 years old) and the need to derive criteria for substances with limited data available. Both of these issues highlight the scale of the problem that regulators are faced with in terms of keeping up with the science and the changing use of chemicals by society to ensure that they are regulating those substances which have the greatest potential to cause environmental harm.

Another issue that was discussed was the importance of being able to implement the criteria that are derived and making sure that the practical aspects that regulators are faced with such as analytical limits of detection and the availability of uncomplicated approaches for making the criteria values more ecologically relevant on a site specific basis. This is an aspect of criteria derivation and development that has been gaining increasing attention over the last decade both in North America and Europe, and a good example of the development of more practical implementation approaches is seen in the development of simplified bioavailability tools such as bio-met in Europe, and the development of empirical bioavailability modelling approaches as an alternative to the complex Biotic Ligand Models that were the only options available in the past.