Lead Biotic Ligand Model Tool
Metals present many challenges to those responsible for assessing hazard and risk to aquatic organisms. Past studies have shown that neither total nor dissolved concentrations of metals are good predictors of their potential effects on ecosystems. Indeed, several physico-chemical water characteristics, such as dissolved organic carbon (DOC), pH and hardness can modify toxicity with several orders of magnitude.
Accounting for the bioavailability of metals, using techniques such as the Biotic Ligand Model (BLM), resolves some of these difficulties. The BLM approach is currently considered as state-of-the-art for predicting metal bioavailability because it integrates existing knowledge about metal speciation in the solution surrounding the organism and the interactions between metal ions and competing ions at the binding sites on the organism-water interface (e.g. epithelial cells in fish gill tissue).
Read more about the Biotic Ligand Model in this case study
Lead BLM Tool
The Lead Chronic Biotic Ligand Model Tool (Lead BLM Tool*) is a programme for anybody interested in bioavailability-based approaches for assessing the chronic effects of lead in the freshwater aquatic environment and combines bioavailability models with detailed species sensitivity distribution (SSD) analyses to derive hazard concentration of lead for a given water body.
The tool is a free online resource that was produced under contract of ILA by ARCHE cvba using biotic ligand models developed to describe lead toxicity by GhEnToxLab, Ghent University (Belgium) and the chemical speciation codes used in Visual Minteq (KTH, Sweden).
How to use the tool
A detailed technical user guide has been developed that provides background information on the lead biotic ligand model and step-by-step instructions for installing the tool. This can be downloaded here.
User-friendly chronic BLM tools
The lead chronic BLM tool requires input of several physico-chemical water characteristics that may not always be available. It is therefore considered more applicable to academic research. However, a user-friendly chronic BLM tool has recently been developed based and validated using the full academic version of the model. This tool, called Bio-met, is available to download here. An alternative tool that functions in a similar manner called PNEC-pro is also available and can be downloaded here. Other tools are also available that allow users to account for effect of water chemistry on the bioavailability (and toxicity) of lead. The lead environmental quality standard screening tool is a calculator that can be used to assess compliance with the European Environmental Quality Standard (EQS) for lead described in the EU Water Framework Directive. This tool, that can be downloaded here, only requires knowledge of water DOC levels. A poster comparing the performance of all the available chronic BLM and DOC tools is available.
Acute BLM Tools
For those are interested in the acute BLM for lead, please download the tool from http://www.hydroqual.com/wr_blm.html. If you are interested in more information or updates, or have any questions concerning the BLM tools please contact ILA Science Manager Jasim Chowdhury.
- See also this video: An introduction to Environmental Quality Standards for Metals. The video is produced by Eurometaux, the European non-ferrous metals association, and Arche Consulting, and provides an introduction to the process of setting environmental quality standards for metals in water.
- ILA has developed a set of aquatic life Ambient Water Quality Criteria (AWQC) for lead for the US and presented this at the 7th World Congress of the Society of Environmental Toxicology and Chemistry (SETAC) in Florida. Read the paper Derivation of BLM-based Ambient Water Quality Criteria for Lead Following US EPA Guidelines: A Comparison with European Approaches.
*The development of lead bioavailability models (including biotic ligand models, BLM) is an ongoing research project and hence the lead-BLM-SSD-normalization tool may undergo revisions from time to time. Under no circumstances will ILA, Ghent University, KTH, or ARCHE cvba be deemed responsible for informing the recipients, including the distributees, of such revisions to the bioavailability models or the lead BLM SSD normalization tool.