SEAWATER QUALITY AT INDUSTRIAL EFFLUENTS DISCHARGE ZONE

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 the ir wastewater directly into the Gulf after in-plant treatment. How far industrial effluents influence the marine environment was assessed us ing Microtox toxicity assays of seawater samples collected twice a wee k 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 la tter site ten samples showed medium to high levels of toxicity. The hi gher incidence of toxicity in the downstream area may be due to the mi xing of effluent from individual discharges and indicate some ineffici ency of the effluent treatment process. The study revealed that the bi ological assay provides effective assessment of water quality. (C) 199 6 IAWQ. Published by Elsevier Science Ltd.