Effect of some heavy metals and nutrients upon the growth of green alga Chlorella vulgaris

Abstract

The present study contained manifestation of toxic effect of two heavy metals (Cadmium and Lead) separately (as single) and in a combination at different concentrations on the growth of green alga Chlorella vulgaris ,also studying effect of adding nutrients (Nitrogen and Phosphorus) in different concentrations on this toxicity. The study was carried out depending on the biomass represented by the total number of cells and then taking into account of the growth rate and doubling time . The results showed the differences of the toxic effect of heavy metals (as separately) were significantly different according to the difference of type, concentration of metals and exposing period, and there were cases of antagonistic effect and others of synergistic effect when the alga was exposed to the alloy of both metals depending on used concentrations and exposing period. The addition of nutrients (Nitrogen 1 and 3 mg/l) with cadmium (1 mg/l) and lead (50 mg/l) had a positive effect on a growth of studied alga and decreased the toxic effect of both metals .The results showed there was a significant increase in the growth rates by increasing the added phosphorus concentrations (0.1-- 0.5 mg/l) with cadmium (1 mg/l) and lead (50 mg/l) in compared with control group