Chronic Toxicity of Cobalt to Marine Organisms: Application of a Species Sensitivity Distribution Approach to Develop International Water Quality Standards.

Abstract

Water quality standards for cobalt (Co) have yet to be developed for the European Union (EU) or the United States (US). The primary objective of this research was to produce a data set comprising marine Co toxicity data that could be used by both the EU and US to determine a predicted no effect concentration (PNEC) and ambient water quality criteria (AWQC), respectively. Ten marine species, ranging from algae to fish, were subjected to chronic Co toxicity tests that were designed to meet international water quality testing standards. Chronic EC10 values ranged from a low of 1.23 μg dissolved Co/L for red algae (Champia parvula) to a high of 31,800 μg dissolved Co/L for the sheepshead minnow (Cyprinodon variegatus). The species sensitivity ranking for chronic marine Co exposure was as follows (from most to least sensitive): C. parvula > Neanthes arenaceodentata (polychaete) > Americamysis bahia (mysid shrimp) > Skeletonema costatum (marine diatom) > Dendraster excentricus (sand dollar) > Mytilus galloprovincialis (mussel) > Strongylocentrotus purpuratus (purple sea urchin) > Crassostrea gigas (oyster) > Dunaliella tertiolecta (marine flagellate) > C. variegatus. Chronic test results indicated that invertebrate and plant species were substantially more sensitive to Co exposure than fish. The chronic toxicity data were used to calculate a species sensitivity distribution (SSD), from which a Hazardous Concentration 5th percentile (HC5) of 7.09 µg dissolved Co/L (95% CI: 0.025-47.3 μg Co/L) was derived. This article is protected by copyright. All rights reserved.