Ecological Toxicity Methods and Metals. An examination of two case studies (8 pp + 1) |
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Authors: | Thomas Gloria Andrea Russell John Atherton Scott Baker Murray Cook |
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Institution: | (1) Thomas P. Gloria, Ph.D. Senior Consultant Five Winds International 35 Bracebridge Rd. Newton, MA 02459-1728 USA t.gloria@fivewinds.com, , ,;(2) Andrea J. Russell Rio Tinto Borax Valencia, CA USA, , ,;(3) John Atherton International Council on Mining and Metals London United Kingdom, , ,;(4) Scott R. Baker International Copper Association New York, NY USA, , ,;(5) Murray Cook International Zinc Association Brussels Belgium, , , |
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Abstract: | Goal, Scope and Background The Apeldoorn Workshop (April 15th, 2004, Apeldoorn, NL) brought together specialists in LCA and Risk Assessment to discuss
current practices and complications of the life cycle impact assessment (LCIA) ecological toxicity (ecotox) methodologies
for metals. The consensus was that the LCIA methods currently available do not appropriately characterize impacts of metals
due to lack of fundamental metals chemistry in the models. A review of five methods available to perform ecotox impact assessment
for metals has been prepared to provide Life Cycle Assessment (LCA) practitioners with a better understanding of the current
state of the science and potential biases related to metals. The intent is to provide awareness on issues related to ecotox
impact assessment.
Methods In this paper two case studies, one a copper based product (copper tube), the other a zinc-based product (gutter systems),
were selected and examined by applying freshwater ecological toxicity impact models – USES-LCA, Eco-indicator 99 (EI 99),
IMPACT 2002, EDIP 97, and CalTOX-ETP. Both studies are recent, comprehensive, cradle-to-gate, and peer-reviewed. The objective
is to review the LCIA results in the context of the practical concerns identified by the Apeldoorn Declaration, in particular
illustrating any inconsistencies such as chemical characterization coverage, species specificity, and relative contribution
to impact results.
Results and Discussion The results obtained from all five of the LCIA methods for the copper tube LCI pointed to the same substance as being the
most important – copper. This result was obtained despite major fundamental differences between the LCIA methods applied.
However, variations of results were found when examining the freshwater ecological toxicity potential of zinc gutter systems.
Procedural difficulties and inconsistencies were observed. In part this was due to basic differences in model nomenclature
and differences in coverage (IMPACT 2002+ and EDIP 97 contained characterization factors for aluminium that resulted in 90%
and 22% contribution to burden respectively, the other three methods did not). Differences were also observed relative to
the emissions source compartment. In the case of zinc, air emissions were found to be substantial for some ecotox models,
whereas, water emissions results were found to be of issue for others.
Conclusions This investigation illustrates the need to proceed with caution when applying LCIA ecotox methodologies to life cycle studies
that include metals. Until further improvements are made, the deficiencies should be clearly communicated as part of LCIA
reporting. Business or policy decisions should not without further discussion be based solely on the results of the currently
available methods for assessing ecotoxicity in LCIA.
Outlook The outlook to remedy deficiencies in the ecological toxicity methods is promising. Recently, the LCIA Toxic Impacts Task
Force of the UNEP/SETAC Life Cycle Initiative has formed a subgroup to address specific issues and guide the work towards
establishment of sound characterization factors for metals. Although some measure of precision of estimation of potential
impact has been observed, such as in the case of copper, accuracy is also a major concern and should be addressed. Further
investigation through controlled experimentation is needed, particularly LCIs composed of a variety of inorganics as well
as organics constituents. Support for this activity has come from the scientific community and industry as well. Broader aspects
of structure and nomenclature are being collectively addressed by the UNEP/SETAC Life Cycle Initiative. These efforts will
bring practical solutions to issues of naming conventions and LCI to LCIA flow assignments. |
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Keywords: | Apeldoorn Declaration metals life cycle impact assessment (LCIA) toxicity methods life cycle management (LCM) |
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