草海底泥原位钝化工程示范及其生态环境效应

选取贵州草海重污染湖区，利用改性粘土钝化剂开展底泥原位钝化技术示范，对示范区内外主要水质参数、浮游生物和底栖动物等进行了对比监测与研究。结果表明：示范工程实施一年后钝化区水体氨氮（NH3-N）和总磷（TP）含量分别降低至对照区的29%和23%，水体溶解氧含量达9 mg·L-1以上，透明度显著增加；钝化区水体藻类总丰度降低40%以上，蓝藻所占比例大幅下降；钝化区沉水植物生长繁茂，水体自净功能明显增强，已形成草型清水生态系统。钝化区与对照区水体浮游动物、底栖水生生物种群及丰度无显著变化，表明钝化剂未对动物生长造成不良影响；原位钝化技术具有快速提升水体透明度和溶解氧含量、抑制底泥污染物释放、降低水体营养盐含量及抑制藻类生长等特点，且实施方便、成本低廉，在湖泊底泥污染治理和水体富营养化防治领域具有广阔应用前景。

Eco-environment effect of in-situ sediment inactivation in Lake Caohai,Southwest China

Modified clay was used as an inactivation agent to control sediment pollution in highly contaminated area of the Lake Caohai, a typical plateau wetland in China.The species, total abundance of phytoplankton, zooplankton, benthos, and water quality were determined both in the experimental and contrast zones.The results show that ammonia nitrogen and total phosphorus contents in the experimental zone had dropped to 29% and 23%, respectively.Dissolved oxygen in the water bodies had increased to 9 mg·L-1 and the transparency had improved obviously.The phytoplankton abundance had decreased by more than 40% and the cyanobacteria were only half of the quantity present in the contrast zone.The lush submerged plants greatly enhanced the self-purification ability of the lake and contributed to restoring the ecosystem in the experimental zone to a clear and healthy state.There are almost no differences in the abundance of zooplankton and benthos between the experimental and contrast zones, which indicates that the inactivation agent was harmless to aquatic organisms.An integrated study indicated that the inactivation agent could quickly improve the dissolved oxygen concentration and transparency in water bodies, restrain the pollutant release from sediments, reduce the nutrient concentration, and control the proliferation of algae.The in-situ inactivation technique was deemed to be low cost and easily implementable, with wide application prospects in eutrophication control and remediation of polluted sediments.