1. Shiraz University
Faculty of Sciences
M.Sc. Thesis in Earth Sciences
ENVIRONMENTAL GEOCHEMISTRY AND
BIOAVAILABILITY OF HEAVY METALS IN COASTAL
AND MARINE SEDIMENTS OF GOWATR BAY
By
Mohammad Javad Nematollahi
Supervised by
Dr. F. Moore
December 2013
2.
3. Abstract
Environmental geochemistry and bioavailability of heavy metals in
coastal and marine sediments of Gowatr bay
By
Mohammad Javad Nematollahi
In this research, distribution and bioavailability of heavy metals in marine and intertidal
sediments of Gowatr bay (also gowadar bay) was studied in order to identify natural and
anthropogenic pollution. For this purpose, 17 surficial sediment samples, and 5 sediment cores
were collected, and analyzed. The results were then compared with local background
concentration. Surficial distribution of heavy metals indicate that maximum concentration of
Copper and Zinc, Lead, vanadium and chromium, nickel and cobalt is related to Pasabandar
harbor, sandy coast, and mudflats of Mangrove jungle, respectively. Calculated correlation
coefficients indicate a positive correlation between Iron, clay fraction, organic matter, and
potentially toxic metals, especially; Cu, Zn, and Ni. Heavy metals distribution at depth was
determined in five sediment cores. Heavy metals are mainly concentrated in cores 3 and 5. Most
sediment cores display surficial Pb enrichment, while Ni and Co are concentrated at depth.
According to calculated geo-accumulation factors (Igeo), zinc and copper show heavy
contamination in Pasabandar harbor. Maximum PLI and RI are also related to Pasabandar harbor.
The results of heavy metals fractionation reveal that Cu and Pb, Mn, and Zn, Ni, Co, Cr, V, and
Fe are primarily concentrated in reducible, exchangeable, and residual fractions respectively. The
dominance of Cu, Pb, Mn, and Zn in non-residual fractions shows high bioavailability and
potential risk of these metals in littoral ecosystem. Marine traffic, along with ship yards activity at
and close to Pasabandar harbor and mangrove jungle, combined with weathering of ophiolites are
apparently responsible for the observed high concentration of heavy metals in Gowatr bay.
Keywords: heavy metal, surficial sediment, Gowatr bay, Pasabandar harbor, mangrove jungle,
bioavailability
