Distribution feature and correlation analysis of COD in Sansha Bay

The investigation of water quality in Sansha Bay was carried out in May and November of 2012，the result showed that the content of COD in the water ranged from 0.52 to 2.13 mg/L，with an average of 0.94 mg/L. The spatial distribution feature showed that COD was gradually decreased from northwest to southeast， and highest in Baima Bay. COD content in autumn was higher than that of in spring. The average content of COD could meet the first class of sea water quality standard COD < 2 mg/L) . Correlation analysis of COD and environmental variables were performed. Active silicate， inorganic nitrogen， total nitrogen and suspended substance were positively correlated with COD. Salinity and pH had a negative significant correlation with COD.