PARENT SESSION
PM6 - Fate & Effects of Metals: Regulation and Risk
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P272) Quiescent Transformation Studies of the Metals Cd, Cu, Ni and Zn for Hazard Identification.
Skeaff, Jim*,1, Adams, William2, McGeer, Jim1, King, Morgan1, 1 CANMET, Mining and Mineral Sciences Laboratories, NRCan, Ottawa, Ont., Canada2 Kennecott Copper, Magna, Utah, U.S.A.
ABSTRACT- Within the framework of the Organisation for Economic Cooperation and Development (OECD) Programme on Harmonisation of Classification and Labelling (HCL) for chemical substances placed on the market, a Draft Transformation/Dissolution (T/D) Protocol has been developed to determine the rate and extent of the transformation of pure metals and sparingly soluble metal compounds to bioavailable species in aqueous media under a set of standard laboratory conditions representative of those gener-ally occurring in the environment. Once determined, this information can be used to evaluate the short term and long term aquatic toxicity of the metal or sparingly soluble metal compound from which the soluble species came and thence the aquatic hazard classification of the metal-bearing substance. In this study, instead of continuous agitation of the substance as provided for in the Draft T/D Protocol, we have used quiescent column conditions to examine the transformation/dissolution characteristics of the metals Cd, Cu, Ni and Zn, and the corresponding metal chlorides. Tests were conducted in both the presence and absence of a small amount of sediment, at pH 8 and, with 5% CO2-air, pH 6. We also tested selected transformation solutions for their ecotoxicity towards Daphnia magna. The experimental results are compared to data obtained by the agitation method and, together with the ecotoxicity data, are interpreted in the context of hazard identification outcomes for the substances under consideration.
Key words: metals, transformation/dissolution, hazard identificaiton, ecotoxicity