Environmental Effects of Emulsions

This report describes a study, undertaken in 2006–7, of the potential toxicity to the environment (ecotoxicity) of cationic bitumen emulsions that are utilized for chipsealing in New Zealand. The ecotoxicities of the separate components of bitumen emulsions are reviewed to evaluate their contribution to emulsion ecotoxicity. Overseas reports on the environmental hazards and impacts of a non-ionic bitumen emulsion (a power station fuel) and runoff from cold mix asphalt are investigated for relevant applications to sealing emulsions. Ecotoxicities are measured for four samples representative of New Zealand emulsions. The implications of the results for possible environmental classification of emulsions by environmental authorities are discussed.