September 24, 2020 by Graham Merrington
Adam, Iain and I, along with colleagues at the International Zinc Association have derived a bioavailability-based zinc Environmental Quality Standard (EQS) for France following recently updated European Technical Guidance, and the work has been published in Environmental Science and Pollution Research. France has high quality, spatially extensive surface water monitoring data that are publicly accessible and importantly, have concurrent sample site measures of pH, dissolved organic carbon (DOC) and calcium; the parameters that most influence zinc bioavailability in freshwaters.
We have derived a national bioavailability-based zinc EQS for France from Biotic Ligand Model calculations for 4645 sites (22,000 samples from 4645 sites in 14 regions). An EQS of 11.3 µg Zn L-1 was derived based on the sensitive waters of the Bretagne region typically of circumneutral pH and relatively low DOC and low dissolved calcium. An indicative assessment of compliance, using the annual average zinc concentrations at each site showed that across France 2% of the sites would exceed this bioavailability-based EQS.Unfortunately, National EQS for zinc used for the assessment of ecological status in freshwaters vary by over two orders of magnitude across 25 European countries. Such variability is likely to reflect inconsistent levels of ecological protection, poor environmental relevance and no account being taken of bioavailability.