October 23, 2015 by Adam Peters

Last week Graham and I attended the Manganese Showcase Symposium organised by the International Manganese Institute in Ottawa. The symposium covered a wide variety of issues relevant to manganese including socioeconomic analyses, the effects of manganese on human health, life cycle analysis of processing sites, and environmental effects. Recent developments suggest that manganese is not a reproductive toxicant. Manganese can cause neurotoxicity when levels are sufficiently elevated, but manganese deficiency also causes adverse effects due to its essential nature. Recent advances in physiologically-based pharmacokinetic modelling, especially for manganese exposure through inhalation, have provided insight into the uptake, elimination, and distribution of manganese to target organs, and developments in toxicity modelling have enabled U-shaped dose response curves to be developed for manganese which take account of both its essentiality and toxicity.

Life cycle assessments of manganese industries have been able to identify the greatest impacts resulting from manganese extraction and processing sites, and enabled robust evaluations of potential manganese recovery or slag processing operations. I presented work that wca did in developing a suite of biotic ligand models for manganese toxicity to fish, invertebrates, and plants in the aquatic environment, and the development of simplified tools to enable implementation of a bioavailable EQS for manganese. Graham presented a generic risk assessment of the potential environmental impacts due to manganese at manganese processing sites.