| Phytoremediation is an economically effective and environmentally friendly soil pollution remediation technology with less secondary pollution.At present,most of the research on phytoremediation technology is based on the pot experiment simulating the real environment,and further research is needed for its real large-scale application in the field.Therefore,the phytoremediation technology of Cd-Pb compound pollution in alkaline cultivated soil was studied in this paper.Firstly,selecting nine species of plants with Cd-Pb pollution remediation potential,namely Solanum nigrum L.,Rumex acetosa L.,Calendula officinalis,Rosa chinensis Jacq.,Sedum plumbizincicola,Rosa davurica,Paeonia suffruticosa Andr.,Tagetes erecta L and Impatiens balsamina L.in a greenhouse.Then,the potential remediation plants were screened by BCF(enrichment factor)and TF(transport factor)in the greenhouse.Finally,potential remediation plants were planted in the field to verify their remediation effect,and the feasibility analysis of field promotion was carried out.The results showed that:(1)Among the alternative plants planted in greenhouses,the Cd content in the stem and leaves of Paeonia suffruticosa Andr.was the highest,and the Pb content in the root of Impatiens balsamina L.was the highest.In terms of plant enrichment ability,Solanum nigrum L.,Rumex acetosa L.,Calendula officinalis,Rosa chinensis Jacq.and Paeonia suffruticosa Andr.,Tagetes erecta L,Rosa davurica,root,Impatiens balsamina L.all had certain enrichment ability for Cd,and the enrichment ability of Pb in Solanum nigrum L.,Rumex acetosa L.and Impatiens balsamina L.is stronger than that of other plants.From plants in terms of transport capacity,Solanum nigrum L.,Calendula officinalis,Rosa chinensis Jacq.,Sedum plumbizincicola,Rosa davurica,Paeonia suffruticosa Andr.and Impatiens balsamina L.on Cd and Pb had certain ability to transport.However,in terms of extraction amount,the extraction amount of Cd and Pb in Rosa davurica,Sedum plumbizincicola and Solanum nigrum L.were too low to be used as the remediation plants in this area.Therefore,the other six plants were selected as the remediation plants for the combined pollution of Cd and Pb in alkaline cultivated soil.(2)The results of field enrichment showed that the stem and leaves of Tagetes erecta L had the highest content of Cd,and the stem and leaves of Rumex acetosa L.had the highest content of Pb among the six selected plants.In terms of enrichment ability,Calendula officinalis and Rosa chinensis Jacq.all had certain enrichment ability for Cd,Rumex acetosa L.,Calendula officinalis and Tagetes erecta L had certain enrichment ability for Pb.From plants in terms of transport capacity,Rumex acetosa L.,Tagetes erecta L and Paeonia suffruticosa Andr.on Cd had certain ability to transport.Rumex acetosa L.,Rosa chinensis Jacq.and Paeonia suffruticosa Andr.on Pb had certain ability to transport.In terms of the extraction amount,the extraction amount of Cd and Pb from Paeonia suffruticosa Andr.was lower than that from the other five plants,and the extraction amount of Cd and Pb from Calendula officinalis was higher than that from the other five plants.(3)The average contents of Cd and Pb in soil decreased by 18.05% and9.01%,respectively,after planting in field,which is technically feasible.The cost-benefit analysis showed that it was economically feasible to plant four kinds of flower plants,such as calendula calendula,Chinese rose,peony and marigold,which could be widely planted.To sum up,It was concluded that the four flower plants of Calendula officinalis,Rosa chinensis Jacq.,Paeonia suffruticosa Andr.and Calendula officinalis could be promoted and applied as remediation plants for the combined pollution of Cd and Pb in alkaline cultivated soil. |
