Fate of alkylphenols, chlorophenols and bisphenol A in the Lake Shihwa, Korea

Full text: Surface water, suspended particles in surface water and sediment samples from the brackish lake, Shihwa, and its surrounding creeks were collected during Aug. 2001 to May 2004 in Korea. Representative endocrine disrupting chemicals (EDCs) such as alkylphenols, chlorophenols and bisphenol A, were determined from each matrix by GC/MS. Among them, alkylphenol compounds were recorded as the major pollutants affecting Lake Shihwa water quality. High concentration of alkylphenols were measured in those matrices in and around industrial complexes. The levels decreased gradually with distance from the industrial areas. Though alkylphenols concentration in sediment varied from that of water and suspended particle, high concentrations were generally found in industrial area and in central part of the Lake Shihwa. Concentrations of nonylphenol from industrial area were similar or higher than US and EU regulatory value which is 1 μg/L. Spatial and seasonal variation of alkylphenol in dissolved water and suspended particulate were similar but not in the sediment. The alkylphenol concentration was the highest in summer and the lowest in winter. There is no annual correlation on the levels of alkylphenol in water and particulate. Phenolic compounds are continuously discharged into Lake Shihwa from surrounding industries and hence the input of alkylphenols increases in time. Alkylphenol compounds were continuously produced by biodegradation of alkylphenol polyethoxylate and it was accumulated in the sediments by adsorption. Nonylphenol and bisphenol A were the major endocrine disrupting chemicals determined in the Lake Shihwa. The contents of nonylphenol and bisphenol A in dissolved water, suspended particle and sediment are 60, 70, 90% and 35, 25, 8%, respectively. The levels of these chemicals measured in creeks were about 25 times higher than those in Lake Shihwa. In order to identify the source and behavior of alkylphenols in the environment, the relationship between nonylphenol and water quality parameters such as salinity, pH, DO, COD, TN and TP were studied. Those parameters point to industrial input as the principle source of alkylphenol pollution to Lake Shihwa. In order to investigate vertical distribution profile of alkylphenols in the sediment, two sediment cores were collected from Lake Shihwa. The concentrations profile indicates that the lowest concentration were at the surface layer and the highest at the bottom. The degradation rate of nonylphenol in the seawater was lower than it's parent compounds namely nonylphenol diethoxylate. Detailed study is underway in our laboratory to understand this fully. (author)