东莞市河道底泥特征及作为绿化种植土的可行性研究

Research on the Characteristics of River Substrates in Dongguan and Their Feasibility as Greening Planting Soil

在广东东莞市沙田镇西太隆河流域综合整治工程中,为解决疏浚污染底泥的后续处理问题,对西太隆河上游、中下游河流交汇处、下游底泥的基本特性进行调查,分析将其改良为绿化种植土的可行性。结果表明:西太隆河底泥的pH值范围在pH 6.45~7.35,渗透率范围在2.17×10^(-4)~8.9×10^(-4) cm/s,土壤质地为粉壤土,上述指标均符合CJ/T 340—2016城镇建设行业标准。该河道底泥养分含量充足但空间异质性较大,靠近下游的底泥养分含量远高于上游河段。靠近河道下游区域受到周围工厂的影响,底泥中的重金属元素含量高,Ni、Cu元素超标严重,未达到种植土的重金属含量最低标准。综合分析上游的河道底泥特性更符合CJ/T 340—2016标准,可通过改良用作绿化种植土,对城市水体环境治理具有重要意义。

In the comprehensive remediation project of Xitailong River basin in Shatian Town of Dongguan City,Guangdong Province,in order to solve the problem of post-treatment of dredged contaminated substrate,the basic characteristics of the substrate in the upper reaches of Xitailong River,the middle and lower reaches of the river confluence and the lower reaches of the river were investigated,and the feasibility of upgrading it to green planting soil was analysed.The results showed that the pH of Xitailong River substrate ranged from pH 6.45 to 7.35,the infiltration rate ranged from 2.17×10^(-4 )to 8.9×10^(-4) cm/s,and the soil texture was powdery loam,all of which met the CJ/T 340-2016 industry standard for urban construction.The nutrient content of the river sediment is sufficient,but the spatial heterogeneity is large,with the nutrient content of the substrate much higher in the downstream than in the upstream reaches.The area near the downstream river is affected by the surrounding factories and the heavy metal elements in the substrate are high,with serious exceedances of the elements Ni and Cu,which does not meet the minimum standards for heavy metal content in plantation soils.A thorough analysis shows that the characteristics of the upstream river substrate is more in line with the CJ/T 340-2016 standard,which can be used as green planting soil through improvement,and is of great importance for the environmental management of urban water bodies.