AWWA WQTC71459

Recently, caffeine has been used as a tool for assessing human impacts on aquatic systems because of its relatively high concentrations detected in surface water as well as its clear anthropogenic origin. Human pharmaceuticals have been extensively surveyed in sewage effluent and river water and proposed as chemical tracers because of their relatively high water solubility and low natural background levels. In this study, the feasibility of using caffeine and human pharmaceutical compounds to identify the human-source contamination in urban marine systems was investigated. Experimental methods included: sample collection; bacterial analysis; and, extraction and instrumental analysis of organic compounds. It was found that a high correlation exists between caffeine and fecal coliform (R2, 0.598), ibuprofen and fecal coliform (R2, 0.364), respectively, in the urban marine system of Singapore, demonstrating that caffeine and ibuprofen are highly related to human-source contamination. Results indicate that caffeine is a suitable chemical tracer in urban marine systems because of its easy detection (in the range of 0.08-2.31 ng/mL), compared with other chemicals monitored. Relative lower concentrations of human pharmaceutical compounds (< 0.2 ng/mL) in urban marine water samples make them hard to be detected, and then limit their use as a chemical tracer. However, their existence can help to validate sewage contamination. The strong correlation between caffeine and ibuprofen also shows the potential to use caffeine as an indicator for the occurrence of emerging pharmaceutical residues in marine water systems. Includes 8 references, table, figure.