Letter Atmospheric corrosion of zinc-based materials: runo rates, chemical speciation and ecotoxicity eects I. Odnevall Wallinder a, * , C. Leygraf a , C. Karl en a , D. Heijerick b , C.R. Janssen b a Division of Corrosion Science, Department of Materials Science and Engineering, Royal Institute of Technology, Dr. Kristinas v. 51, SE-100 44 Stockholm, Sweden b Laboratory for Environmental Toxicology and Aquatic Ecology, University of Gent, J. Plateaustraat 22, BE-9000 Gent, Belgium Received 1 September 2000; accepted 13 September 2000 Abstract In order to ®ll some major gaps of knowledge for future risk assessments, an interdisci- plinary research eort is going on in order to generate relevant zinc runo rate data from various commercial zinc-based materials, and to explore the relation between the chemical speciation of zinc in runo water and its ecotoxicity. This study presents runo rates, based on 1-year exposures of 15 zinc-based materials, which range from 0.07 to 3.5 g/m 2 year. When collected immediately after release from the various zinc-based surfaces, chemical speciation modeling of the runo water suggests that nearly all zinc >95%) is present as hydrated Zn 2 ions, the most bioavailable speciation form. Evaluation of zinc runo for possible environ- mental eects was performed through growth inhibition test with a green alga, Raphidocelis subcapitata. The results show a high correlation between the amount of zinc in the runo and the environmental eect, suggesting, again, that all zinc is present as hydrated Zn 2 . The in- sight gained aids in predicting actual ecotoxicity eects during environmental fate of zinc, based on chemical speciation of zinc in the runo. Ó 2001 Elsevier Science Ltd. All rights reserved. Keywords: Zinc; Atmospheric corrosion; Runo rate; Chemical speciation; Bioavailability; Ecotoxicity www.elsevier.com/locate/corsci Corrosion Science 43 2001) 809±816 * Corresponding author. Tel.: +46-8-7906621; fax: +46-8-208284. E-mail address: ingero@corrosci.kth.se I. Odnevall Wallinder). 0010-938X/01/$ - see front matter Ó 2001 Elsevier Science Ltd. All rights reserved. PII:S0010-938X00)00136-0