Bioaccumulation of metals from tannery sludge by Typha angustifolia L.

The metal bioaccumulation capability of a common anchored hydrophyte, Typha angustifolia L. was studied in a green house trial. The plants could absorb significant amounts of the heavy metals like chromium, copper and zinc from tannery sludge. Different concentrations of tannery sludge were prepared in water and plants of T. angustifolia were exposed to the sludge for 30, 60 and 90 days. A significant reduction in sodium chloride percentage, chlorides and chemical oxygen demand (COD) was observed. The percentage reduction in all metals was significant. Cadmium and lead were found to be totally absent. A greater reduction of metals was observed in 30% concentration of sludge. A maximum reduction of 62% for Na, 42% for Cr, 38% for Cu and 36% for Zn was observed in 30% sludge after 90 days exposure of T. angustifolia. The bioaccumulation potential of T. angustifolia was greater for the heavy metals especially for Cr. The maximum metal uptake, observed after 90 days exposure of T. angustifolia, was 6,698 mg kg(-1) for sodium, 20,210 mg kg(-1) for chromium, 16,325 mg kg(-1) for zinc and 7,022 mg kg(-1) for copper in the roots. In shoots, the uptake was 3,745 mg kg(-1) for sodium, 10,150 mg kg(-1) for chromium, 3,509 mg kg(-1). for copper and 7,025 mg kg(-1) for zinc. Aerial parts of T. angustifolia accumulated less heavy metal than the corresponding roots. T. angustifolia is suitable for the decontamination of most of the harmful metals from tannery sludge.