Assessment of water quality and pollution in Gurunagar fishery harbour, Jaffna, Sri Lanka

Abstract

Coastal marine water pollution is caused by anthropogenic activities either directly or indirectly. Substances released into marine coastal environment result in deleterious effects such as harmful to living resources, hazards to human health, hindrance to marine activities including fishing. As such, Gurunagar harbour is often polluted by several waste effluents generated within the region. Research was conducted with the objective to determine the quality of water in the fish landing site at Gurunagar and type of wastes discharged into the main water stream. Investigations were carried out for six months period from January to June 2020. Three potential sampling locations were selected along three main drainages where amalgamation takes place at the coastal region. Samples were collected from 10 m, 30 m and 60 m at the interior portion of the harbour whereas control unit was kept at 500 m at the exterior portion of harbour. Fifteen water quality parameters were analyzed to find out the level of contamination in the water. Results showed that physical parameters such as temperature, salinity, total suspended solids, colour and turbidity were kept under the tolerance level. Chemical parameters such as BOD, COD, Nitrate, and Phosphate were accounted above the limit as 139.00 ± 29.57 mg/l, 306.70 ± 70.5 mg/l, 78.70 ± 8.03 mg/l, and 1.42 ±0.2448 mg/l, respectively. There was no significant difference between three main drainage channels considered. Hazardous wastes of oil and grease accumulated as 14.333 ± 2.345mg/l in the harbour water and, the Noxious heavy metals namely Hg and Pb were estimated as 0.03544 ± 0.02845 mg/l and 1.97 ± 0.1815 mg/l, respectively; and these concentrations are crucially above the tolerance limits. The Hg concentration in Jaffna Teaching Hospital drainage was reported as 0.0315 ±0.02247 which is inevitably higher than the threshold level. It was found parameter variables along with the sampling distances and significantly high value was obtained at the distance of 10 m from the coast. The present study recommends that initiatives should be made by the government officials to adopt an effective waste disposal and management system among the coastal communities, in the future.