Metal Contamination Assessment in the Sediments of the Red Sea Coast of Saudi Arabia

Benthic Foraminifera as Bio-indicators of Coastal Marine Environmental Contamination in the Red Sea-Gulf of Aqaba, Saudi Arabia

To assess heavy metals contamination in shallow marine environments using benthic foraminifera as bio-indicators. Forty-six species of foraminifera were found in 33 benthic samples from the Saudi Arabian coast of the Red Sea-Gulf of Aqaba. Forty-six species belonging to 27 genera and 10 families under the Textularina, Rotalina, and Miliolina suborders were recorded in the study area. The most common genera of the recorded fauna were Peneroplis (37.2%), Coscinospira (15.06%), Sorites (10.36%), and Quinqueloculina (7.76%). The influx of clastic sediments would dilute the abundance of foraminifera species, and It may be the main reason for the decrease in abundance Concentrations of Fe, Mn, Cu, Ni, Zn, Pb, Cr, Co, and Cd were measured in the four common species of benthic foraminifera (Sorites orbiculus, Peneroplis planatus, Peneroplis pertusus, and Coscinospira hemprichii) using inductively coupled plasma mass spectrometry. The average values of heavy metals in the study area show that Iron was the most abundant metal (3367 μg/g), followed by Mn (142 μg/g), Cu (30 μg/g), Zn (24 μg/g), Cr (21 μg/g), Ni (14 μg/g), Pb (7 μg/g), Co (4.6 μg/g), and Cd (0.82 μg/g). Iron concentrations recorded in the foraminiferal tests in the study area were lower than those from the Jeddah area of Saudi Arabia. Other metals were found at higher concentrations than those recorded off the Red Sea coast of Saudi Arabia and Egypt. The heavy metals concentrations in the study area may be attributable to terrestrial influx or anthropogenic activities. The increase of abundance of epiphytic foraminifers and the absence of opportunistic foraminifers show normal the environment in the study area.

Pollution assessment of the Red Sea-Gulf of Aqaba seawater, northwest Saudi Arabia

The water pollution index (PIj), degree of contamination (C_d), heavy metal pollution index (HPI), and statistical analyses were used to assess seawater pollution and identify the possible sources of heavy metals from the Red Sea-Gulf of Aqaba coastline, northwest Saudi Arabia. Concentrations of Cr, Sb, Co, Ni, Cu, Zn, Cd, As, Fe, Mn, Hg, and Pb were analyzed and interpreted in 33 surface seawaters samples. The mean heavy metals of seawater were in the following order: Zn (5.51 μg/l) > Ni (2.45) > As (2.43) > Cu (2.34) > Mn (2.20) > Fe (1.81) > Pb (1.31) > Sb (0.64) > Co (0.31) > Cr (0.26) > Cd (0.05) > Hg (0.008). The spatial distribution of heavy metals showed high levels in some individual samples, especially nearby the residential cities, may be due to anthropogenic sources. PIj and C_d indicated light and low pollution for the seawater samples, respectively, while HPI indicated low pollution for 10 samples and medium pollution for the rest ones. The lack of significant correlations between metal pairs (except Cu and As) indicated different sources of pollution. Pollution indices, principal component analysis, and Pearson's correlation coefficient reveal that the quality of seawater in the Red Sea-Gulf of Aqaba coastline is mainly controlled by geogenic processes with minor anthropogenic input.

Assessment of contaminants in the northwestern Bay of Bengal

The coastal sediments in the northern Bay of Bengal has undergone contamination due to the heavy metal contribution from rivers. To evaluate the status of contamination in the inner shelf region of the Bay of Bengal, a sediment core chronologically constrained using 210Pb dating technique from the northwest Bay of Bengal was investigated for several trace elements. To assess sediment quality, enrichment factor (EF), geo-accumulation index (Igeo), and Modified Nemerow Pollution Index (MPI) were derived. The influence on ecology by individual contaminants and combined contaminants was evaluated using the potential ecological risk factor (Eri) and modified ecological risk index (MRI). The single-element pollution indices indicated that the sediment has no significant pollution by individual elements. However, the multi-elemental approach shows slight pollution in the sediment core. The ecology is at low risk by contaminants present in the sediment. Comparison of the elemental values of shelf sediment with adjacent riverine and estuarine samples demonstrates the role of estuarine environment and/or high riverine flux of sediments causing either removal or dilution of trace elements during its transport from the river to the sea.