Assessment of current water pollution status and accumulation of trace metals in Mugil cephalus from Negombo estuary

Abstract

Industrial and domestic solid waste dumping are the major pollution sources polluting the Negombo estuary. Polluted water and sediments in the estuary may cause heavy metals accu mulation in fish. Therefore, this study was aimed to assess physico - chemical parameters in water, heavy metals (Zn, Pb, Hg, Cd, Cu and Cr) in water and fish tissues, to compare the levels of metals in fish tissues with the available maximum recommended standards. The study was carried out from January to December 2016 and monthly sampling was done from the selected sampling sites. Physico - chemical parameters and metal levels were detected through standard methods. Water quality results revealed that temperature, salinity, pH, EC, TSS, BOD and nutrient levels were below the maximum permissible limits and COD levels were higher than the discharge of industrial wastewater quality standards of the CEA, Sri Lanka. According to the results, metal levels in water of the estuary were below the tolerance limits for the wastewater standards of the CEA except for Hg. In the Northern region of the estuary, higher Pb, Cu and Cr levels were reported from the fish species collected. As the “X-Press Pearl” shipwreck has posed a serious threat to the Negombo estuary, this study can be considered as a baseline for the future studies on water and sediment pollution and bioaccumulation of heavy metals in edible fish species from the estuary.