Distribution of salinity and trace elements in surface seawater of the Arabian Gulf surrounding the State of Qatar

This study reports a preliminary survey of salinity variations and trace element concentrations in seawater collected from the coastal areas of Qatar. The concentrations of trace elements in seawater were determined by inductively coupled plasma atomic emission spectroscopy. The concentrations of trace elements were less than 5 ppb for As, Cd, V, Ag, Cr, Mn, Co, Ni, Be, Cu, Tl, and Sn; less than 15 ppb for Pb, Zn, Fe, and Se; less than 50 ppb for Sb, Al, and Ba; and less than 15 ppm for Si, Sr, and B. The average salinities of eastern and western coasts were 42 and 51 ppt, respectively. This salinity variation across the coastal regions is due to the marginal enclosed nature of the sea and brine discharge from desalination plants of the Gulf region. Among analyzed elements, Al, Ba, Fe, Zn, Sb, and Pb were significantly higher at some specific locations than their general average concentrations in the region. These site-specific variations in trace element concentrations may be related to anthropogenic inputs from industrial activities. Strong correlations were obtained for Al-Fe, Sb-Pb, and Sr-B combinations confirming their coexistence from common pollution sources. The trace element average concentrations in Qatari seawater are within the national and environmental protection agency seawater quality standards, they and exhibited similar concentrations to that of Red Sea. Outcomes of this study can be applied to mitigate pollution, improve water management efficiencies and assist sustainable operations of desalination plants.