Seasonal variations in levels of Heavy metals in muscles of crab Sesarma boulengeri collected from Al-Garaf canal at Thi Qar province, Iraq

Abstract

The present work is aiming at investigating seasonal variations in levels of some heavy
metals (Ni, Cd, and Cu & Zn) in muscles of the crab Sesarma boulengeri. Samples
were collected from Al-Garaf canal at Thi Qar governorate. The study extended from
March 2004 to February 2005. Specimens were collected from a location supply cities
of Basrah, Thi Qar, Shatra and Garaf water's purification boards with crude
freshwater for domestic uses. The surrounding areas are affected with sewage and
agricultural disposals. It also represent mixing zone of water masses of various
compositions. Elements found to vary seasonally in their levels and analyses of muscles
indicate that Ni occupied the first position and revealed the highest levels, in general.
The minimal recorded accumulative values (200.11 μg/g dry wt) was in Spring and the
highest (243.20 μg/g dry wt) in summer. Zinc occupied second accumulation levels and
showed the minimal (55.13 μg/g dry wt) in spring, whereas Cd, by no means, exhibited
the minimal concentrations and the lowest value (4.82 μg/g dry wt) was in winter.
Causes and effects of trace elements were discussed.