Ecological Toxicity Methods and Metals. An examination of two case studies (8 pp + 1)

Implications of considering metal bioavailability in estimates of freshwater ecotoxicity: examination of two case studies

“…We revisited the case studies examined by Gloria et al (2006), first a Cu-based product of Cu pipe and second a Zn-based gutter system for an average residential application. For Cu pipe used in a typical American house over its lifetime, Gloria et al (2006) relied on the comprehensive inventory compiled by Ecobalance (2000a, b) under commission to the International Copper Association that represented data from 31 sites and accounted for 58% of the Cu production by refinery and 74% by solvent extraction.…”

“…Their analysis used life cycle inventory (LCI) data for total emissions of various chemicals as part of the cradle-to-grave analysis of both case studies. Gloria et al reported the outcomes of the ecotoxicity impact category as a result of using five different LCIA models to calculate freshwater ecotoxicity potential of metals: USES-LCA 1.0, Eco-indicator 99 (EI 99), IMPACT 2002, EDIP 97, and CalTOX-ETP. The goal of this paper was to examine the effect on the outcome of the metal case studies presented by Gloria et al (2006) of using the new method for estimating freshwater ecotoxicity. We calculated and compared metal CFs and LCIA outcomes for freshwater ecotoxicity of each of the two studies using four models: USES-LCA 1.0 (Huijbregts et al 2000), USES-LCA 2.0 (van Zelm et al 2009), USEtox™ using the interim approach , and the new method with the geochemical correction in USEtox™ .…”

“…The CF is determined by normalizing the CTP of a substance relative to other chemicals under defined model conditions (Gandhi et al , 2011. Gloria et al (2006) explored the consequences of using metal CFs from different LCIA models that do not explicitly account for metal speciation and bioavailability. They examined two case studies: (1) use of Cu pipe for supplying domestic water and (2) an average Zn-based gutter system for residential use.…”

“…In this paper, we compared and assessed the consequences of using the new method versus currently available LCIA models for calculating freshwater ecotoxicity, as applied to two case studies previously examined by Gloria et al (2006): (1) the production of copper (Cu) pipe and (2) a zinc (Zn) gutter system. Methods Using the same inventory data as presented by Gloria et al (2006), we calculated and compared the LCIA outcomes for freshwater ecotoxicity of each case study using four models: USES-LCA 1.0, USES-LCA 2.0, USEtox™ using the previous approach, and USEtox™ using the new method. Since the new method requires specification of water chemistry for the freshwater compartment, we explored the effect of using seven freshwater archetypes.…”

“…For both case studies, differences in ecotoxicity scores were not significant for the infinite vs. 100 years time scale. Conclusions Accounting for metal bioavailability and speciation by using USEtox™ (new) when calculating CFs decreased by 1-4 orders of magnitude the total metal freshwater ecotoxicity scores (Σ CF×emissions) attributable to metal emissions tallied for Cu pipe and Zn gutter system case studies (Gloria et al 2006). This broad range came from the model used in comparison to USEtox™ (new) and the choice of freshwater archetype.…”