W10 AM Life Cycle Approaches to Water Resources
Wednesday, 16 November 2005: 8:00 AM - 11:40 AM in 341-342

(ADA-1118-517380) Evaluation of USES Model for Deriving Characterization Factors for Metals.

Adams, W.¹, Verdonck, F.², Van Sprang, P.³, Russell, A.⁴, ¹ Rio Tinto, Murray, UT, USA² Euras, Gent, BE, BE³ Euras, Gent, BE, BE⁴ Borax, Valencia, CA, USA

ABSTRACT- Two workshops, Montreal and Apeldoorn were a collaborative effort between ICMM and the UNEP-SETAC Life Cycle Initiative. These workshops identified key issues in the life cycle assessment of metals that need improvement in order to develop a robust LCIA methodology. It is recognized that the characterization factors (CFs) for metals require additional research to improve their reliability (www.leidenuniv.nl/interfac/cml/ssp/projects/declaration). Current models used to develop assessment factors do not include important process for metals such as speciation, essentiality, bioavailability, and other metal specific fate parameters. The models also have limited compartmentalization and ability to deal with spatial and temporal changes in exposure. Toxicity potentials are standard values used in LCA to enable a comparison of toxic impacts between substances. Huijbrechts (2001) calculated toxicity potentials for 181 substances utilizing the USES model for the six impact categories, i.e. freshwater aquatic ecotoxicity (AETPfresh), marine aquatic ecotoxicity (AETPsalt), freshwater sediment ecotoxicity (SETPfresh), marine sediment ecotoxicity (SETPsalt), terrestrial ecotoxicity (TETP) and human toxicity (HTP) after initial emission to the compartments air, freshwater, seawater, industrial soil and agricultural soil, respectively. Marine Ecotox potential for metals is usually high using this approach whereas most open ocean metal concentrations are very low. A sensitivity analysis of the USES model was untaken using copper as an example. Results of the study indicate: fate processes on the global scale (moderate, arctic and tropical) are determining the marine water and sediment ecotoxicity potentials for copper most; inclusion of speciation and bio-availability processes would be very beneficial as the dominant metal fate process is currently partitioning; sedimentation processes from the water and burial in deep sediment layer are the second most important fate parameter; more accurate estimates of input parameters should be used, especially for the PNECwater and PNECsediment; and all partition coefficients should be updated. Implications for further model development will be discussed.

Key words: metals, copper, LCIA, USES