1. Biogeochemistry Research Centre; Plymouth University; Drake Circus Plymouth PL4 8AA UK
2. Division of Analytical & Environmental Toxicology, Department of Laboratory Medicine & Pathology, Faculty of Medicine and Dentistry; University of Alberta; Edmonton AB T6G 2G3 Canada
3. Shell Global Solutions International B V; Rock and Fluid Science; Kessler Park 1 2288 GS Rijswijk The Netherlands
4. Water Science and Technology Directorate; Environment Canada; 867 Lakeshore Road Burlington ON L7R 4A6 Canada