CHARACTERISTICS OF ORGANIC PHOSPHORUS IN SEDIMENTS OF LAKE DIANCHI, CHINA

The amounts and forms of organic phosphorus (OP) in surface sediments of Lake Dianchi, Yunnan, South China, were examined using a sequential chemical extraction method. OP in thirty three sediment samples of Lake Dianchi were defined as labile, moderately labile and nonlabile fractions based on their solubility during the extraction procedures. The results showed that the concentration of OP in sediments decreased from the north to the south regions excluding the samples from the northwest region polluted by phosphate ore mining. The average content of total phosphorus (TP) in sediments far exceeds 2000mg/kg, showing that the sediments have been heavily polluted. Moderately labile and nolabile organic phosphorus are the main compositions, accounting for about 90% of the OP in sediments. There is no obvious correlation between OP fractions and organic matter (OM). However, labile, moderately labile and nonlabile organic phosphorus are significantly correlated with OM if excluded the nine samples in the southwest zone. Labile and moderately labile OP are also positively correlated with labile inorganic phosphorus (IP), indicating their potential bio-availability.