Phosphorus status on overlying water - sediment of typical riparian wetlands in Hangjiahu plain region and its impact to water quality
杭嘉湖平原湿地底泥-上覆水磷素状况及其水质响应研究

Typical riparian wetlands were investigated to understand the status and characteristics on phosphorus (P) of overlying water and sediments located in south region of Taihu Lake basin, along with a case study of Xiazhuhu wetland. The field investigation shows that total phosphorus (TP) in sediment reached 0.17 to 1.20 mg·g-1 with the corresponding maximal P sorption capacity of 228.1 to 824.5 mg·kg-1, implying tend of P accumulation in sediment. There was significant relationship between NaOH+EDTA-P extractable P and TP/Olsen-P in sediment. TP in overlying water was found in rang of 0.036 to 0.944 mg·L-1, which commonly reached over the critical level responding for water eutrophication. Total particulate P (TPP) concentration in overlying water samples occupied 69.1%±15.0% of TP, while dissolved reactive P (DRP) being relatively low. Wetlands located around the water reservation areas were found lowest in term of P concentration in overlying water, compared with agricultural/livestock farming/living zones. Typical investigation and case study proved that there was no significant relationship between TP concentration in overlying water and TP (and/or Olsen-P) level in sediments. The variation of phosphorus in overlying water of those wetlands would be not predicted only by the status of P accumulation along with the corresponding levels of different forms of P in sediment.