Water and sediment quality in a tropical swamp used for agricultural and oil refining activities.

The Godineau Swamp in Trinidad receives anthropogenic input from agricultural and oil refining activities, sewage and domestic waste. This study was conducted in order to provide a comprehensive baseline dataset for the swamp, to assess water and sediment quality in the swamp, and to identify hotspots and possible sources of pollutants to the swamp. Ten sampling stations were established in the swamp during April/May and July 2002. Water quality parameters monitored included physicochemical measurements (pH, temperature, dissolved oxygen and salinity), total suspended solids, and nutrients (ammonia, nitrites, nitrates and total phosphorus). Sediments were analyzed for hydrocarbons, heavy metals and total organic carbon. Temperatures and pH of water in the swamp were ambient; dissolved oxygen was low in many instances (<3 mg/L). In the dry season, there was saltwater intrusion along the Oropuche River up to the most easterly station. Levels of ammonia and phosphorus concentrations were suggestive of periodic inputs of agricultural and domestic wastes. Hydrocarbons concentrations in sediment were above ambient levels and suggestive of contamination from industrial activities. Sediments from the Godineau River contained elevated nutrients, hydrocarbons, metals and TOC compared with other stations. The results of this study indicate some degree of pollution of the Godineau swamp, which prompts the need for the implementation of measures beneficial for wise use of the swamp.