METAL BIOAVAILABILITY; TOXICITY IN SEDIMENTS AND ACCUMULATION IN FIREWORM EURYTHOE COMPLANATA (PALLAS, 1766) (POLYCHAETA: AMPHINOMIDAE) FROM BULEJI KARACHI, PAKISTAN

Abstract

Eurythoe complanata (Pallas, 1766) is a marine polychaete worm, which is considered as an indicator species of heavy metal pollution. During present investigation the worm and sediment samples were collected from the intertidal zone of the Buleji coast in Karachi, at low tide, from January to March 2016. Atomic Absorption Spectrophotometer was used to determine the concentrations of Zn, Pb, Mn, Cu, Cd, Cr, and Ni. The results showed that the mean concentrations of Zn was the highest 14.86 ± 1.64 in dry tissues of worms and 36.16 ± 3.04 µg g-1 dry weight in sediments while Ni was the lowest 0.60 ± 0.18 (dry tissues of worms) and 1.00 ± 0.15 µg g-1 were recorded in sediment. The trend of the metals concentration, in a decreasing order, was found to be Zn> Pb> Mn> Cu> Cr> Cd > Ni for the worm and Zn> Mn> Pb> Cu> Cr> Cd> Ni for the sediments samples. The bio-concentration factor (BCF) for all the metals studied were found to be <1. The correlation between body weight and the concentration of the heavy metals in the worm showed a positive relationship for Zn, Pb and Ni while for Cd, Cr, Cu and Mn negative relationship was observed.