Escherichia Coli and Biophysicochemical Relationships of Seawater and Water Pollution Index in the Jakarta Bay

Problem statement: Relationships between Escherichia coli (E. coli) and biophysicochemical properties of seawater at different seasons and water pollution index were investigated in the Jakarta Bay, Indonesia. Approach: Water quality data taken at different seasons (Early Rainy Season (ERS) in November 2007 and Late Dry Season (LDS) in August 2008) were analyzed. Additionally, to compare pollution level at different seasons, Nemerow-Sumitomo Water Pollution Index (WPI) was used. Results: Significant correlation of E. coli occured with only few parameters in the ERS, but with more parameters in the LDS. This might be due to the rainfall intensity in the ERS that was potential to dilute seawater and reduce concentration of some parameters, especially along the offshore stations. However, at the same time, the freshwater coming from land had capacity to force out the polluted water in 13 river systems flowing into the bay; hence it could generate more pollution along the onshore stations. Seawater pollution level slightly increased in the ERS in respect to the addition of polluted water from rivers. In this season, none station was clean, 20 stations were slightly polluted, six stations were moderately polluted and six stations were highly polluted. Meanwhile in the LDS, the number of stations following the above WPI criteria were 9, 16, 3 and 4, respectively, indicating less pollution level. Conclusion/Recommendations: The overall results showed that E. coli exhibited significant correlations with more water parameters in the LDS and the WPI showed a little increase in the ERS.