Seawater quality at industrial effluents discharge zone

Abstract

Shuaiba Industrial Area (SIA) accommodates 38 plants, of which 15 are located in the eastern sector and the other 23 in the western sector. The factories, being near the shore of the Arabian Gulf, discharge their wastewater directly into the Gulf after in-plant treatment. How far industrial effluents influence the marine environment was assessed using Microtox toxicity assays of seawater samples collected twice a week for six months from two stations located upstream and downstream of SIA. Out of 50 samples each collected from Station No 1 and Station No 2, only two samples from the former showed toxicity, whereas at the latter site ten samples showed medium to high levels of toxicity. The higher incidence of toxicity in the downstream area may be due to the mixing of effluent from individual discharges and indicate some inefficiency of the effluent treatment process. The study revealed that the biological assay provides effective assessment of water quality.