Ferronickel slag toxicity tests on Chlorella vulgaris and Artemia sp.

Acute effects of ferronickel slag toxicity on Chlorella vulgaris and Artemia sp. were studied. Tests were conducted on ferronickel slag to determine the concentration of heavy metals leached out to the environment. Toxicity tests were also carried out on the organisms with minimum exposure duration of 4 days or until the occurrence of a negative effect. About 400 cells mL(-1) of C. vulgaris and 20 individuals of Artemia sp. were used in each of the reactors with media containing slag concentration ranged from 0 to 50%. Results showed that the IC50 (inhibition concentration) value of the percentage of slag (w/v) for C. vulgaris was 5-10%. Slag toxicity test on Artemia showed that LC50 (lethal concentration) for the percentage of slag was also between 5-10%. The study proved beyond doubt the acute effects of the slag at low concentration (10% w/v) as indicated by the inhibition of growth of 60% of the C. vulgaris population and deaths of more than 50% of the Artemia in the reactors. Hence the study suggests wise use of the slag to avoid disturbances to environment and society at large.