Effect of some heavy metals ions on the chlorophyll a pigment of Nostoc linkia and Hapalosiphon aureus


Two Cyanophyt A species : Nostoc linkia and Hapalosiphon aureus were exposed to some heavy metals ions {silver (Ag1+) , cobalt ( Co2+) and lead (Pb2+) } in different concentrations (1 , 5 and 10) mg/l to study their effects on the growth ( i.e. Chlorophyll A ) of these species. Chlorophyll A pigment was extracted from these species after different exposure periods (0 , 1 , 2 , 3 and 4 ) weeks for using as physiological parameter in the toxicological studies with Cyanophyta.Results showed that the effect of heavy metals has not significant differences (p> 0.05) between these two algal species, the effect wasSignificantly (p< 0.05) depended on the metal type and its concentration in the growth medium so as the exposure periods, the effect of heavy metals on the growth and pigment of these two species was in thefollowing sequences:- Ag > Co > Pb