底泥调控剂对感潮河涌沉积物中重金属的影响

Effects of Regulatory Agent on the Heavy Metal Stability in Tidal Sediments

以典型的电器工业区重污染感潮河道——佛山市顺德区容桂街道内河涌为研究对象,选取一段河道,投加含硝酸钙的调控剂,采用BCR形态提取法研究调控剂对感潮河涌沉积物中重金属的影响,以评价调控剂对重金属的稳定化效果.结果表明,①调控剂使得重金属Cu、Zn、Pb和Cr的可还原态和可氧化态占总量的百分比降低;②调控剂能有效促进底泥中的重金属Cu、Zn、Pb和Cr向残渣态转化,投加调控剂处理22 d后,重金属Cu、Zn、Pb和Cr的残渣态占总量的质量分数分别升高了4%、20%、21%和23%,这在不同程度上降低了底泥Cu、Zn、Pb和Cr的可生物利用性;③调控剂能使Cu、Pb和Cr的弱酸提取态增加,而使Zn的弱酸提取态下降,即增加了Zn的稳定度而降低了Cu、Pb和Cr的稳定度.总体上,调控剂对底泥重金属Cu、Pb和Cr的稳定化效果并不理想,而对底泥重金属Zn有一定的稳定化效果,但效果不明显.

The object of this work was to evaluate the feasibility of calcium nitrate-regulatory agent for the stabilization of heavy metals in tidal sediments. The pilot-scale treatment was deployed in a section of the urban river in Ronggui, Foshan, which was heavily contaminated with Cu, Zn, Pb and Cr. For the remediation of the contaminated sediment, chemical speciation and stability of four elements were studied. The results indicated that： a）the percentage of four elements associated with reducible fraction and oxidizable fraction was decreased with the treatment of regulatory agent; b） the regulatory agent could effectively promote Cu, Zn, Pb, and Cr in sediment distributing in the residual fraction, which were increased by 4% , 20% , 21% and 23% after being treated by dosing regulatory agent for 22 days, with lower bioavailability in environment; c） the concentration of acid soluble fraction of Cu, Pb and Cr was increased except Zn, In general, the effect of stabilization for heavy metals Cu, Zn, Pb and Cr by regulatory agent is not ideal except Zn which has a certain effect, but the effect is not obvious.