菱镁矿区镁粉尘污染土壤的植物修复效果评价

Assessment of phytoremediation for magnesium-rich dust contaminated soil in a magnesite mining area

菱镁矿在开采和煅烧过程中产生的镁粉尘严重损害矿区土壤性质和植被生长,然而至今对菱镁矿污染土壤修复仍无成熟的方法。本研究通过不同添加量镁粉尘处理（0、2%、5%和10%）以及配合施用磷酸二氢钙[Ca（H2PO4）2·H2O]的盆栽实验,探讨羊草（Aneurolepidium chinense）、披碱草（Elymus dahuricus）、剪股颖（Agrostis stolonifera）和碱茅（Puccinellia distans）对菱镁矿区镁粉尘污染土壤的修复效果。结果表明：羊草和披碱草对土壤镁粉尘污染具有极强的耐性,而剪股颖和碱茅耐性中等;4种植物对土壤镁的富集能力均不强,地上部分镁浓度为1.6～8.6 g·kg-1,生物富集系数均小于1,转运系数为0.5～3.1。在轻度镁粉尘污染处理中,4种植物对土壤镁有较好的去除效果;配施Ca（H2PO4）2·H2O显著促进了镁粉尘处理植物的生长,提高了植物对土壤镁的去除能力,在中度和重度镁污染处理的效果更强。因此,在轻度镁粉尘污染土壤上,配施Ca（H2PO4）2·H2O、种植碱茅和羊草,不但能恢复菱镁矿区废弃地植被,还能有效去除土壤镁;对于中度和重度镁粉尘污染土壤,可通过配施Ca（H2PO4）2·H2O、种植羊草和披碱草来加快菱镁矿区废弃地的植被恢复。

The magnesium （Mg）-rich dust from magnesite mining and calcination has damaged the soil and vegetation severely. However, the knowledge on remediation of Mg-rich dust contam- inated soil is scarce. We conducted a pot experiment in the greenhouse to evaluate the remedia- tion effects of Aneurolepidium chinense , Elymus dahuricus , Agrostis stolonifera and Puccinellia dis- tans, combined with application of Ca （ H2 PO4 ） 2 amounts of Mg-rich dust （0, 2% , 5% and 10% ） dahuricns had a very strong tolerance to Mg-rich dust ~ H2 O, on soil contaminated by different We found that： （1） A. chinense and E. contamination and the tolerance of A. stolo- nifera and P. distans was moderate; （2） These plants did not hold a strong Mg enrichment capacity, as the concentration of total Mg in shoot was 1.6-8.6 g kg-1, the bioconcentration fac- tor was less than 1 and the translocation factor was 0.5-3.1. These four plants had a good effect on the removal of Mg in the lightly contaminated soil （2%） ; （3） Application of Ca（ H2PO4 ）2 ： H2O significantly enhanced the plant biomass and the removal of soil Mg, particularly in the 5 % and 10% treatments. Our results suggested that planting A. chinense and P. distans with the application of Ca（ H2PO4 ）2 ： H2O could not only restore vegetation, but also remove soil Mg effectively in lightly Mg-contaminated soil. In soil, planting A. chinense and E. dahuricus celerate the vegetation restoration. moderately and severely Mg-rich dust contaminated with the application of Ca（ H2PO4 ）·H2O could ac