July 8, 2019 by Iain Wilson


The new version of bio-met, version 5, was released in June 2019. This tool estimates the potential risk to the aquatic environment posed by copper, nickel, zinc and lead after considering bioavailability. The tool calculates Local HC5 values and Bioavailable Metal Concentrations based on information on local water physicochemistry. It has been developed as part of the bio-met project and has been designed to operate in Microsoft Excel. The tool is based on calculations from Biotic Ligand Models (BLM) but is much easier and quicker to use than the models that it has been developed from. It is currently intended to be used as part of a tiered risk assessment or as an early tier in an Environmental Quality Standard (EQS) compliance assessment, and is suitable for use by both regulators and regulated industries.

The following key improvements to the tool since the previous version have been:

  • Lower range of the Ni EQS is changed to 4 µg Ni/L.
  • The DOC resolution of the underlying database with key water parameters has been increased.
  • Worst-case competition waters have been added to the underlying database
  • The option to include Ambient Background Concentrations (ABC) for Zn in the bio-met calculations has been removed, as this calculation was not in line with the most recent guidance of the WFD. However, local background concentrations may be taken into consideration following compliance assessment if appropriate.

Further information regarding the tool, including its operation, validation and more can be found here: www.bio-met.net.