Abstract
The aim of the study was to determine the heavy metals (Fe, Cu, Zn, Co, Cr, Ni, Pb and Cd) in mangrove sediments and their associated fiddler crab (Austruca sindensis (Alcock, 1900) from the mangroves of Hawks Bay, Karachi, Pakistan. According to the sediment quality guideline, sediment was contaminated by Ni, Cu, Cr, Pb and Cd and assessed infrequent or frequent adverse effect of these metals on benthic fauna. The mean accumulation pattern of the heavy metals was observed as Pb > Cu > Zn > Fe > Ni > Cr > Co > Cd in the fiddler crabs. All metals concentrations were detected significantly greater in the male crab as compared to female crabs, except Cr. Fiddler crabs were noticed the highest bioaccumulation of Pb, which was observed two to three times higher concentrations than those in the sediment. Sediment biota accumulation factor (SBAF) also revealed the active accumulation of Pb in both genders, whereas Cu, Cd, and Zn showed active accumulation only in male crabs. The results indicated that A. sindensis may be employed in pollution monitoring programs, especially Pb contamination, along the coastal areas of Pakistan.
