Sedimentary coprostanol in Kaohsiung Harbour and the Tan-Shui Estuary, Taiwan

Coprostanol in sediments from Kaohsiung Harbour and the Tan-Shui Estuary has been analysed. In the Kaohsiung Harbour sediments, coprostanol has a concentration range between 0.58 and 128 μg g^-1 dry wt with a mean of 20.8 μg g^-1 dry wt; higher concentrations are found near the mouths of rivers. Moreover, a significant log-log correlation is found between total coprostanol concentration and oil hydrocarbon concentration (r=0.803^*). In Tan-Shui Estuary sediments, coprostanol ranges in concentration from 1.00 to 230 μg g^-1 dry wt with an average of 63.5 μg g^-1 dry wt; relatively high levels of coprostanol (> 10 μg g^-1) with 5β 5β+5α cholestanol ratios > 0.7 indicate positive sewage pollution. This probably results from an input from the sewage outfall, anoxicity, shallow water depths, inadequate tidal flushing, etc. Additionally, highly significant correlations have been found for coprostanol and cholesterol (r=0.986^*) and for cholestanol and cholesterol (r=0.981^*); these relationships are thought to be mediated predominantly by sediment micro-organisms in the reducing environment.