Assessing the effect of leachate of copper slag from the ISASMELT process on cell growth and proximate components in microalgae, Chlorella vulgaris (Beijerinck)

Abstract

Dumping or disposal of huge quantities of slag (containing significant amounts of heavy metals) generated during matte smelting and refining of copper (Cu) is likely to result in environmental toxicity. Detailed chemical studies of Cu-containing slags indicated long-term persistence and poor leachability. Since chemical analyses alone are not sufficient for quantifying biological impact, the effect of copper slag leachate (CSL) on growth and proximate components in marine microalgae, Chlorella vulgaris (Beijerinck), were assessed under laboratory conditions. An inhibitory effect of CSL on cell growth (14.3%) was well below the defined criteria of 50% using algal growth inhibition test. Cellular concentrations of the total protein (TP) in CSL-exposed cultures were significantly higher than the controls. Although the cells of C. vulgaris exposed to CSL accumulated numerically elevated levels of total lipid (TL) compared to control, exposure of C. vulgaris to 100% CSL did not induce stress proteins as evidenced by SDS-PAGE. Further studies assessing the changes in the growth rate and lipid profile might help in complete understanding of the nature of CSL-induced toxicity in microalgae.