The coastal area of the Western Province is faced with an acute environmental problem due to undesirable pollution of its waters from various wastes. The overall objective of this research was to determine the present status of water quality along the coastal line in the Western Province. In addition, an attempt was made to suggest recommendations to mitigate the pollution levels. The study was carried out from November 2011 to April 2012 and sampling was done on a monthly basis from Bentota to Negombo in selected coastal area. Dissolved oxygen (DO), water temperature, pH, turbidity, conductivity, total dissolved solids (TDS) and salinity were determined in situ and water samples were subjected to laboratory analysis using standard methods. Coastal water quality results revealed that, the average ammonia concentration (0.22 ± 0.16) mg/L and water temperature (30.0 ± 3.8) 0 C were below the maximum permissible limits of the proposed ambient water quality standards for Sri Lankan coastal waters. Average pH (7.91 ± 0.34) was within the ideal pH range for above standards whereas the mean concentration of DO was below the saturation level. An average value determined for Biochemical Oxygen Demand (12.08 ± 4.47) mg/l was much higher than the permissible threshold limit (>5 mg/l) which indicates the gross organic and inorganic pollution in all selected sampling locations in western coast. Proposed ambient coastal water quality standards should be modified using coastal water quality monitoring data and expert views and comments. Further studies needed to determine heavy metal concentration and bacteriological parameters to obtain clear picture of the pollution status.

Suspended matter and nutrient are major factors for water pollution studies and this study is focused on behavior and loading of suspended sediment and nutrient in Upper Kotmale Basin (UKB). Nanu Oya, Dambagasthalawa Oya and Agra Oya are three major streams fed by Kotmale Oya proper in UKB. Eight sampling locations were selected considering all major rivers and eight months samples were collected on monthly basis. Data analysis is used cluster analysis and descriptive statistic was used for analysis of nutrient and suspended sediment loading in streams. Results reveal that, highest nutrient loads bring by Nanu Oya and calculated mean daily nutrient loads namely; ammonia-N, nitrite-N, nitrate-N, and dissolve phosphate were found to be in

Madu Ganga is the latest addition to the Ramsar International Convention of Wetlands. Najas marina is an alien aquatic plant and 0.5 m long that are often branched toward the upward portion of the plant. The objective of the study was to study the impact of salinity and nutrients for the growth of Najas marina. Samples were collected for analysed water quality parameters from March, 2006 to January 2007 in the lagoon. Mapping was done using Garmin GPS map 76CS and Arc GIS used to developed maps.Mean nutrient such as, nitrate nitrogen, ammonia nitrogen and orthophosphate concentrations were observed 0.26 ± 0.3 mg/l, 0.057 ± 0.04 mg/l, and 0.354 ± 0.77 mg/l subsequently. Mean salinity variation in bottom and surface are 6.38 ± 6.65 ppt and 4.31 ± 4.68 ppt. Higher bottom salinity was observed in location number 02 (near to sea mouth) and Najas marinawas not present in the area. Najas marina was also not recorded in upper part of the lagoon and fresh water streams studied. High density of Najas marina plants were observed in sampling location 07, 08 and 09, because of the high nutrient concentration flowing through feeding tributaries. More than 25 % of lagoon area was covered by Najas marina.

Consumption of fish contaminated with non essential heavy metals such as Pb, Hg and Cd metals which exceed the required limits pose a risk to human health. Bioaccumulations of heavy metals in fish depend on several factors such as increased levels of industrial pollution and domestic solid waste dumping in the estuary. Based on the pollution inputs into the estuary, it is considered that different localities within the estuary are polluted at different rates.The objectives of this study were to determine the non essential heavy metals concentration in fish tissues and assess the seasonal variations in the ecosystem. For this study, fish tissue samples were collected from nine sampling locations along the North (n =3), South (n=2), West (n=2), and East (n=2) parts of the estuary for a period of one year from January to December 2014. Fish tissue heavy metals levels were analyzed employing standard methods. Results revealed that the average concentrations (mg/kg) varied from Pb 0 to 0.15 ± 0.06, Cd 0.35 ± 0.16 to 1.04 ± 0.28 and Hg 0.0005 ± 0.0004 to 0.05 ± 0.046 mg/kg respectively. The detected levels were below the maximum permissible limits for hazardous substances in fish and fishery products for recommendation of FAO. The detected lead, mercury and cadmium contents in fish tissue were below the standard limits defined for each element < 0.5 mg/kg < 0.05 mg/kg and < 0.05 mg/kg respectively. Significant differences (P < 0.05) were observed for Pb and Hg depending on fish tissues. The levels of Pb and Hg metals in muscle tissue were lower than the standard limit for FAO. The value obtained on Cd 1.04 ± 0.28 mg/kg concentration was much higher than the permissible threshold limit observed in the north, south, east and west regions. The most prominent increases in Pb and Cd metal concentrations in fish tissue were found during the October, November and December study of 2014, which corresponded to peak periods from October, November and December which apparently coincided with the second inter monsoon of the island respectively.

The Weligama Bay is a one of the rocky shorelines in the coastline of Sri Lanka and Polwatta River is the major river which enters to south part of the Bay. The study objectives were to find out the sedimentary characteristic, and water quality status in Polwatta River and Weligama bay. Results indicated that, mean water temperature, pH, NO 3