矿山污染水库锑形态及分布受溶解性有机质影响研究

Influence of dissolved organic matter on antimony speciation and distribution in mining polluted reservoir

自然水体中溶解性有机质(DOM)具有丰富的官能团,对溶解态锑(Sb)的形态转化(真溶解态和胶体态)及毒性有潜在影响.以碳酸盐岩区受锑矿山排水污染水库为研究对象,运用三维荧光光谱、平行因子分析法、切向流超滤等技术及环境化学理论,结合水体理化性质,分析DOM与Sb、Fe形态及二者相互作用的关系.结果表明:在水体弱碱性及水化学类型为Ca^(2+)-Mg^(2+)-HCO_(3)^(-)的水质背景下,水体溶解态Sb浓度较高,且上层浓度高于下层,平均约为112.74μg·L^(-1),其中,真溶解态Sb约占86%,主要以SbO_(3)^(-)形态存在;溶解态Fe浓度高于Sb,真溶解态Fe为其主要形态,且下层浓度高于上层,在水库碱性水环境条件下易水解生成胶体;DOM有陆源和内源两种输入途径,主要有陆源腐殖质(C1)、芳香族蛋白质和类富里酸(C2)、类酪氨酸蛋白质和类腐殖酸(C3)等3种荧光组分,其中以C2组分为主;腐殖化程度较低,相对分子质量较小;DOM与Sb、Fe的相互作用中,胶体态有机碳更有助于Fe向有机无机复合胶体转化,会抑制铁氧化物胶体颗粒对Sb的吸附.本研究结果可为深入认识Sb在水库的迁移转化提供科学依据.

Dissolved organic matter(DOM)in natural water is rich in functional groups,and has a potential influence on speciation transformation and toxicity of dissolved antimony(Sb),including truly dissolved and colloidal Sb.A reservoir polluted by antimony mining activity was selected as study object.The relationship of DOM with Sb and Fe speciation and the interaction between the two metals were study by resorting to technologies of excitation-emission matrix fluorescence spectroscopy,parallel factor analysis and tangential flow ultrafiltration and theories of environmental chemistry.The results showed that the water was weakly alkaline and had a hydrochemical type of Ca^(2+)-Mg^(2+)-HCO_(3)^(-).There had a high Sb concentration with an average value of 112.74μg·L^(-1),and it was higher in upper layer than in lower layer.The truly dissolved Sb accounted for about 86%and mainly existed in the speciation of SbO_(3)^(-).The concentration of dissolved Fe was higher than that of Sb,and it was easy to generate colloid under such alkaline condition.The truly dissolved Fe was also the main speciation,while its concentration was relatively higher in lower layer.The DOM were contributed terrestrial and endogenous inputs,mainly contained three kinds of fluorescent component including terrigenous humus(C1),aromatic protein and fulvic acid like(C2)and tyrosine like protein and humic acid like(C3),and the proportion of C2 was relatively high.The humification degree and molecular weight were low.The DOM interacted with Sb and Fe,and the colloidal DOM could promote Fe to transform to organic-inorganic complex,which might inhibit the adsorption of iron oxides colloid to Sb.This study can provide scientific basis for further understanding migration and transformation of Sb in reservoir.