蜂窝煤灰渣和磷肥结合修复铅污染贫磷潮土的研究（Remediation of Lead Polluted Chaotu Soil with Low Phosphorus Availability by Application of Honeycomb Briquette Combustion Residue and Phosphorus Fertilizer）

利用蜂窝煤灰渣和磷肥结合稳定铅污染贫磷(Olsen-P=2.50mg·kg-1)潮土中铅的可行性.采用盆栽试验,设置0和500mg·kg-1两个Pb用量,灰渣用量分别为干土质量的0%和2%,P:Pb分别为0和4.种植黑麦草,植物生长85d后收获,测定植物产量、土壤DTPA-Pb、Olsen-P含量、pH值和电导率(EC).结果表明,在两个Pb用量及两个P:Pb比例下,加入灰渣后,土壤的DTPA-Pb含量均降低,平均降低5.61%.其中加铅未加磷处理灰渣效果达到0.05的显著水平,各加Pb处理中,同时加入磷肥和灰渣处理土壤的DTPA-Pb含量最低;加入灰渣后处理土壤中的Olsen-P含量均增加,平均增加了2.71mg·kg-1,各处理土壤pH值上升约0.1个单位,加入灰渣也导致各处理土壤的EC增加.各处理条件下加入灰渣后植物产量均减小.在未加磷土壤中加入Pb后,土壤Olsen-P含量显著增加(p<0.05),表明高铅有效性下,植物可能通过根系分泌物增加了土壤磷的有效性.以上结果表明,蜂窝煤灰渣有可能用于降低污染土壤中铅的有效性,但其对植物生长的抑制作用需要克服.

Remediation of Lead Polluted Chaotu Soil with Low Phosphorus Availability by Application of Honeycomb Briquette Combustion Residue and Phosphorus Fertilizer

Lead(Pb)is one of the most common and toxic heavy metals in soil.Phosphorus(P)amendment is found to be the most effective way of immobilizing Pb in soil.However,application of large amount of P is both a waste of P resource and a threat of the environment quality.Honeycomb briquette combustion residue(HBCR)is a kind of solid waste in rural area of China,it is often discarded as a waste.The purpose of this study was to explore the feasibility of immobilizing Pb in a Chaotu soil with low P availability by application of P fertilizer and HBCR.A Chaotu soil with low P availability(Olsen-P=2.50mg·kg-1)was spiked with 0 or 500mg·kg-1 Pb,single superphosphate was applied in Pb-spiked soil at P:Pb=0 or 4,<2mm HBCR was applied at the rates of 0% or 2% of the soil(dry weight),ryegrass(Lolium perenne L.)was planted in all treatments.After ryegrass plants were harvested,soil DTPA-Pb,Olsen-P,pH,electrical conductivity(EC)and plant yield were determined.HBCR amendment reduced soil DTPA-Pb contents at both 0 and 500mg·kg-1 Pb rates,average reduction reached 5.61% for all treatments with HBCR application,the effect of HBCR in soil with Pb-spiking and without P amendment was significant at 0.05 level.Soil amended with P and HBCR had the lowest DTPA-Pb contents in all Pb-spiked soils.HBCR application also increased Olsen-P contents(2.71mg·kg-1 on the average)in all treatments.HBCR increased soil pH for 0.1 unit and resulted in higher EC compared with soil without HBCR application,however,only the effect on pH was significant(p<0.05).HBCR resulted in lower ryegrass yield in all treatments.An interesting result was that in soil spiked with 500mg·kg-1 Pb and without P application,Olsen-P contents increased significantly compared with soil without Pb-spiking(p<0.05),suggesting that in a soil with very low P availability,stress of high Pb availability may result in more root exudates,which enhances P availability in the soil.Thus,HBCR amendment can reduce Pb availability and improve P availability;however,its negative effect on plant growth should be subjected to further research if it is to be used for immobilizing Pb in soil.