Bioaccumulation of Pb^2＋ and Its Effects on Growth, Morphology and Pigment Contents of Spirulina （Arthrospira）platensis

A laboratory experiment was conducted to assess the bioaccumulation of Pb2 and its effects on growth,morphology andpigment contents of Spirulina (Arthrospira) platensis.The specimen cultured in Zarrouk liquid medium was treated with variousinitial metal concentrations (0,5,10,30,50 and 100 μgmL-1).The growth of S.platensis was adversely affected by Pb2 at high con-centrations (30,50 and 100 μg mL-1).However,at low concentrations (5 μg mL-1),Pb2 could stimulate its growth slightly.The pig-ment contents (chlorophyll α and β carotene) were decreased in a dose-dependent manner.The highest reductions (67% and 53%respectively in chlorophyll α and β carotene) were observed in 100 μg mL-1 treatment group.The LC50 (96 h) of Pb2 was measured as75.34μg mL-1.Apart from a few cases of filament breakages at elevated concentrations (50 and 100μg mL-1),morphological abnor-malities are not specific.Metal bioaccumulation increased with Pb2 concentrations,but decreased with exposure time.The maxi-mum accumulated amount was 188 mgg-1 dry weight.The bioconcentration factor (BCF) reached to a peak at day 2,followed by agradual reduction for all the exposure concentrations.S.platensis is able to tolerate considerably high Pb2 concentrations.Conse-quently it can be used as a potential species to remove heavy metal from contaminated waters.

Bioaccumulation of Pb2+ and Its Effects on Growth, Morphology and Pigment Contents of Spirulina (Arthrospira)platensis

A laboratory experiment was conducted to assess the bioaccumulation of Pb2+ and its effects on growth,morphology andpigment contents of Spirulina (Arthrospira) platensis.The specimen cultured in Zarrouk liquid medium was treated with variousinitial metal concentrations (0,5,10,30,50 and 100 μgmL-1).The growth of S.platensis was adversely affected by Pb2+ at high con-centrations (30,50 and 100 μg mL-1).However,at low concentrations (5 μg mL-1),Pb2+ could stimulate its growth slightly.The pig-ment contents (chlorophyll α and β carotene) were decreased in a dose-dependent manner.The highest reductions (67% and 53%respectively in chlorophyll α and β carotene) were observed in 100 μg mL-1 treatment group.The LC50 (96 h) of Pb2+ was measured as75.34μg mL-1.Apart from a few cases of filament breakages at elevated concentrations (50 and 100μg mL-1),morphological abnor-malities are not specific.Metal bioaccumulation increased with Pb2+ concentrations,but decreased with exposure time.The maxi-mum accumulated amount was 188 mgg-1 dry weight.The bioconcentration factor (BCF) reached to a peak at day 2,followed by agradual reduction for all the exposure concentrations.S.platensis is able to tolerate considerably high Pb2+ concentrations.Conse-quently it can be used as a potential species to remove heavy metal from contaminated waters.