CAJ | 학술논문

土壤重金属污染已成为人类面临的共同挑战，典型的重金属污染场地包括金属矿山、公路沿线、工业集中区、农业耕地等。对于事关农业安全生产的大农区，土壤超量重金属往往导致农产品品质下降甚至使用价值丧失，由此造成的经济损失不可估量。实际上，农作物体内累积重金属量与土壤“活性”重金属关系更加密切，这部分重金属主要以可交换态存在，在一定条件下能够与碳酸盐结合态、Fe-Mn氧化态、有机结合态和残渣态相互转换。因此，明确土壤条件对重金属有效性的作用规律，有望从源头上降低重金属对农作物的污染风险。基于前期研究成果，以华中大农区酸性网纹红土为检测对象，采用Tessier连续提取-原子吸收光谱法（AAS）揭示不同条件对红土Pb形态转化的非生物调控机制。结果表明：红土样品 Pb 总量为32．56 mg·kg－1，低于《土壤环境质量标准》一级标准推荐值，但比全国土壤Pb 平均含量要高。不同形态Pb 含量分布为残渣态＞Fe-Mn氧化态＞有机结合态＞碳酸盐结合态＞可交换态，其中残渣态 Pb 占 Pb 总量的54．55％。红土pH 值通过改变无机胶体和有机质表面电荷量来控制Pb的结合行为和可交换态含量；不同含水率导致红土氧化还原电位差异，进而影响Pb的形态转化行为。此外，秸秆加入量和老化时间也能改变Pb的形态分布，但残渣态Pb含量始终最高。红土Pb的 Muller指数Igeo为0．3025，表明土样采集区人为污染值得注意。Tessier连续提取-AAS法能有效表征红土Pb赋存形态的非生物转化机制。
토양중금속오염이성위인류면림적공동도전，전형적중금속오염장지포괄금속광산、공로연선、공업집중구、농업경지등。대우사관농업안전생산적대농구，토양초량중금속왕왕도치농산품품질하강심지사용개치상실，유차조성적경제손실불가고량。실제상，농작물체내루적중금속량여토양“활성”중금속관계경가밀절，저부분중금속주요이가교환태존재，재일정조건하능구여탄산염결합태、Fe-Mn양화태、유궤결합태화잔사태상호전환。인차，명학토양조건대중금속유효성적작용규률，유망종원두상강저중금속대농작물적오염풍험。기우전기연구성과，이화중대농구산성망문홍토위검측대상，채용Tessier련속제취-원자흡수광보법（AAS）게시불동조건대홍토Pb형태전화적비생물조공궤제。결과표명：홍토양품 Pb 총량위32．56 mg·kg－1，저우《토양배경질량표준》일급표준추천치，단비전국토양Pb 평균함량요고。불동형태Pb 함량분포위잔사태＞Fe-Mn양화태＞유궤결합태＞탄산염결합태＞가교환태，기중잔사태 Pb 점 Pb 총량적54．55％。홍토pH 치통과개변무궤효체화유궤질표면전하량래공제Pb적결합행위화가교환태함량；불동함수솔도치홍토양화환원전위차이，진이영향Pb적형태전화행위。차외，갈간가입량화노화시간야능개변Pb적형태분포，단잔사태Pb함량시종최고。홍토Pb적 Muller지수Igeo위0．3025，표명토양채집구인위오염치득주의。Tessier련속제취-AAS법능유효표정홍토Pb부존형태적비생물전화궤제。
The soil contamination of heavy metals,from the areas of mine,highway,industrial area,agricultural land and so on, is nowadays a serious issue all over the world.The contamination of heavy metals in large agricultural area might lead to the de-crease of products quality and economic value.Actually,the accumulation amount of heavy metals by crops is much more related to the activated speciation,which is exchangeable and able to transform to the forms of carbonates,Fe-Mn oxides,organic mat-ter and residual.Thus,the investigation to reveal the transformation mechanism of heavy metals caused by soil conditions might be appropriate to reduce the contaminated risk to crops.The vermicular red soil from the agricultural area of central China was used as sample in the paper,and the Tessier Sequential Extraction Procedure-atomic absorption spectroscopy (AAS)was applied to discuss the chemical speciation and non-biological transformation mechanism of Pb at different conditions.The results showed:the total amount of Pb is 32. 56 mg·kg-1 ,lower than the first level of the State Environmental Quality Standard for Soils.The Pb content of different speciation,with decreased concentration,is residual (54. 55% of total Pb content),bound to Fe-Mn oxides,bound to organic matter,bound to carbonates and exchangeable.The pH value of red soil is related to the charge amount on surface of inorganic colloids and organic matter,and the water content of red soil would change the redox potential, effective for the variation of chemical speciation of Pb.The environmental factors of straw dosage and aging time could change Pb speciation,with Pb concentration of residual form the highest.The Muller Index of Igeo is 0. 302 5,indicating the contribution of human activities.The Tessier Sequential Extraction Procedure-AAS is effective for the non-biological transformation mechanism identification of Pb speciation in red soil.