The International Journal of Life Cycle Assessment

, Volume 15, Issue 2, pp 143-147

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

The clearwater consensus: the estimation of metal hazard in fresh water

  • Miriam L. DiamondAffiliated withDepartment of Geography, University of Toronto Email author 
  • , Nilima GandhiAffiliated withDepartment of Chemical Engineering, University of Toronto
  • , William J. AdamsAffiliated withRio Tinto
  • , John AthertonAffiliated withICMM 35/38 Portman Square
  • , Satyendra P. BhavsarAffiliated withOntario Ministry of the Environment
  • , Cécile BulleAffiliated withEcole Polytechnique de Montréal, 2900 Edouard-montpetit
  • , Peter G. C. CampbellAffiliated withInstitute National de la Recherché Scientifique
  • , Alain DubreuilAffiliated withMining and Mineral Sciences Labs, CANMET
  • , Anne FairbrotherAffiliated withExponent
    • , Kevin FarleyAffiliated withDepartment of Civil and Environmental Engineering, Manhattan College
    • , Andrew GreenAffiliated withInternational Zinc Association
    • , Jeroen GuineeAffiliated withInstitute of Environmental Sciences, University of Leiden
    • , Michael Z. HauschildAffiliated withTechnical University of Denmark, DTU-MAN
    • , Mark A. J. HuijbregtsAffiliated withDepartment of Environmental Science, Radboud University
    • , Sébastien HumbertAffiliated withRue Verte
    • , Karen S. JensenAffiliated withDepartment of Basic Science and Environment, University of Copenhagen
    • , Olivier JollietAffiliated withSchool of Public Health, University of Michigan
    • , Manuele MargniAffiliated withEcole Polytechnique de Montréal, 2900 Edouard-montpetit
    • , James C. McGeerAffiliated withWilfrid Laurier University
    • , Willie J. G. M. PeijnenburgAffiliated withNational Institute for Public Health and the Environment
    • , Ralph RosenbaumAffiliated withEcole Polytechnique de Montréal, 2900 Edouard-montpetit
    • , Dik van de MeentAffiliated withDepartment of Environmental Science, Radboud University
    • , Martina G. VijverAffiliated withInstitute of Environmental Sciences, University of Leiden


Background, aim, and scope

Task Force 3 of the UNEP/SETAC Life Cycle Initiative has been working towards developing scientifically sound methods for quantifying impacts of substances released into the environment. The Clearwater Consensus follows from the Lausanne (Jolliet et al. Int J Life Cycle Assess 11:209–212, 2006) and Apeldoorn (Apeldoorn Int J Life Cycle Assess 9(5):334, 2004) statements by recommending an approach to and identifying further research for quantifying comparative toxicity potentials (CTPs) for ecotoxicological impacts to freshwater receptors from nonferrous metals. The Clearwater Consensus describes stages and considerations for calculating CTPs that address inconsistencies in assumptions and approaches for organic substances and nonferrous metals by focusing on quantifying the bioavailable fraction of a substance.


A group of specialists in Life Cycle Assessment, Life Cycle Impact Assessment, metal chemistry, and ecotoxicology met to review advances in research on which to base a consensus on recommended methods to calculate CTPs for metals.

Conclusions and recommendations

Consensus was reached on introducing a bioavailability factor (BF) into calculating CTPs where the BF quantifies the fraction of total dissolved chemical that is truly dissolved, assuming that the latter is equivalent to the bioavailable fraction. This approach necessitates calculating the effects factor, based on a HC50EC50, according to the bioavailable fraction of chemical. The Consensus recommended deriving the BF using a geochemical model, specifically WHAM VI. Consensus was also reached on the need to incorporate into fate calculations the speciation, size fractions, and dissolution rates of metal complexes for the fate factor calculation. Consideration was given to the characteristics of the evaluative environment defined by the multimedia model, which is necessary because of the dependence of metal bioavailability on water chemistry.


Comparative toxicity potentials Freshwater ecotoxicity Life cycle impact assessment Metal bioavailability Nonferrous metals