ICP-OES研究黄河三角洲贝壳堤岛土壤中有效态重金属的含量与空间分布特征

采用电感耦合等离子体发射光谱法高效、快速地测定了黄河三角洲贝壳堤岛土壤中重金属As，Cd，Cu，Fe，Hg，Mn，Pb，Se和Zn的有效态浓度，研究了它们在贝壳堤岛土壤中的空间分布特征，并对土壤中有效态重金属的分布规律、影响因素及保护区土壤环境状况进行了分析。结果表明：黄河三角洲贝壳堤岛土壤样品中9种有效态重金属的含量除镉(Cd)和汞(Hg)稍高外，其余均远远低于国家土壤环境质量标准中的一级背景含量，贝壳堤岛土壤整体处于清洁水平。从水平分布来看，由于背海侧受人类干扰较多，且海水淋洗较少，七种重金属(As，Cd，Cu，Fe，Mn，Pb，Zn)有效态含量背海侧明显高于向海侧，且呈显著差异(p≤0.05)。从纵向土壤剖面分析，受土壤机械组成、人为取沙和地形与水流方向的影响，有效态重金属浓度平均值随剖面样品中<0.5 mm粒径土壤颗粒所占比例的增加而增加，随>0.5 mm粒径土壤颗粒所占比例的增加而减小；贝壳堤岛土壤中的重金属有向下运动的趋势，大部分有效态重金属含量的最大值都位于表层以下各层，但各层重金属含量整体上变化不大。贝壳堤岛土壤中重金属As，Cd，Cu，Fe，Pb，Zn可能有大致相同的来源，而与Hg，Mn和Se的来源不同。综合来看，黄河三角洲贝壳堤岛土壤环境未受到明显外源污染，贝壳堤岛土壤中有效态重金属主要来源于土壤母质滤食性贝类对海水中重金属的富集、风化过程中土壤颗粒对环境中重金属的吸附，以及外源工业区重金属污染物的迁移转化。

A Probe into the Contents and Spatial Distribution Characteristics of Available Heavy Metals in the Soil of Shell Ridge Island of Yellow River Delta with ICP-OES Method

With the application of ICP-OES (Inductively Coupled Plasma-Optical Emissio n Spectrometry),available heavy metals (i.e.As,Cd,Cu,Fe,Hg,Mn,Pb,Se,Zn) in the soil of Shell Ridge Island of Yellow River Delta are rapidly determ ined.The spatial distribution characteristics in the soil of Shell Ridge Isla nd are studied,and the distribution rules and influence factors of available heav y metals in soil are analyzed.As indicated in the conclusion,for the contents of nine available heavy metals in the soil samples from Shell Ridge Island of Ye llow River Delta,all elements,except for Cadmium (Cd) and Mercury (Hg),fall f ar below the level 1 background content as specified in the National Environment al Quality Standard for Soils.In this sense,the overall soil of Shell Ridge Is land is at clean level.As indicated in the horizontal distribution,due to more human disturbances at the back side of sea and less seawater leaching,the cont ents of seven available heavy metals (As,Cd,Cu,Fe,Mn,Pb,Zn) are significan tly higher than that at the seaward side,and there are significant variations (p≤0.05).As indicated in the analysis of longitudinal soil profile,due to the influences of soil mechanical composition,artificial sand borrowing,terra in and water flow direction,the average concentration value of available heavy metals rise with the increased proportion of soil particles (particle size <0.5mm) in the profile sample whereas declines with the increased proportion of soi l particles (particle size >0.5 mm).There is a downward movement trend of the heavy metals in the soil of Shell Ridge Island,and the maximum value of most av ailable heavy metal contents are located at every layer under the surface layer.However,there are no obvious changes in the overall contents of heavy metals i n every layer.Such heavy metals as As,Cd,Cu,Fe,Pb and Zn in the soil of She ll Ridge Island may roughly have the same source,yet different from the source of Hg,Mn and Se.Synoptically speaking,the soil environment in the Shell Ridge Island of Yellow River Delta is not subject to obvious external pollution,while the available heavy metals in the soil of Shell Ridge Island mainly come from the pa rent material filter feeding bivalve for concentration of heavy metals in seawat er,soil particles for the absorption of heavy metals in the environment during weathering process and the migration & transformation of heavy metal pollutants from external industrial regions.