杭嘉湖平原湿地底泥-上覆水磷素状况及其水质响应研究

    选取太湖流域南冀31处代表性滨岸带湿地采样点进行底泥-上覆水磷素状况面上调查,并选取该区腹地下渚湖湿地作为典型案例研究.面上调查表明,湿地底泥含总磷(TP)0.17～1.20 mg·g-1,最大吸附量(Qmax)为228.1～824.5 mg·kg-1,存在富磷化趋势.底泥NaOH+EDTA-P的积累与TP密切相关,并伴随其积累Olsen-P含量提高.湿地上覆水含TP 0.036～0.944 mg·L-1,普遍达到水体富营养化水平;总颗粒态磷(TPP)占TP含量的69.1%±15.0%,溶解态活性磷(DRP)相对较低;水源区湿地水体磷素水平低下.面上调查与典型案例下渚湖湿地研究发现,底泥TP及(或)Olsen-P与对应上覆水TP浓度之间没有显著相关性,仅从内源底泥富磷水平及其组分特征分析不能直接预测太湖流域南冀滨岸带湿地上覆水的磷素变化趋势.

Phosphorus status on overlying water - sediment of typical riparian wetlands in Hangjiahu plain region and its impact to water quality

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.