Cd (II), Pb (II), and A1 (III) stock standard solutions
(1.0 g liter 1) were prepared by dissolving 1.0 g of
cadmium, lead, or aluminum (99.9%) in the adequate
acid medium and made up to 1 liter with distilled
water.
Dry algal samples (400-600 mg) were digested in
glass tubes with a 3:2 mixture of sulfuric and nitric acid
and gradually heated in an aluminum block up to
150°C (Agemian et al., 1980).