Purpose

In this study, rates of arsenic, cadmium, chromium, copper, lead and zinc contents in agricultural soils from Eghlid County, south of Iran, were determined to assess the soil pollution and potential ecological risk index (PERI) and also spatial distribution of such elements.

Method

A total of 100 topsoil specimens were collected from 100 sampling stations. In the laboratory, after acid digestion the element contents in soil samples were determined using ICP-OES. Then, the soil contamination and also ecological risk of the soil were assessed using various indices especially Igeo, PI, IPI, PLI and PERI. Also, the spatial distribution maps of the studied elements in soil specimens were made using the kriging interpolation technique by ArcGIS software (10.4).

Results

Based on the results, the mean contents (mg/kg) of the elements in specimens were 1.85, 2.80, 19.04, 19.35, 7.17 and 38.77 for As, Cd, Cr, Cu, Pb and Zn, respectively. Arsenic and Cu contents were comparable to background values, while Cd contents were higher than their corresponding background values. The results of principal component analysis (PCA) and hierarchical cluster analysis (HCA) revealed that Cd had anthropogenic sources; while, other elements originated from natural sources. Pollution index (PI) values of As, Cd, Cr, Cu, Pb and Zn varied in the range of 0.45–1.49, 0.52–32.09, 0.096–0.33, 0.36–1.35, 0.18–0.32 and 0.23–1.59, with mean values of 0.92, 12.17, 0.21, 0.68, 0.21 and 0.96, respectively. The integrated pollution load index (PLI) values of the specimens with an average value of 0.84, indicated that 65% and 35% of soil samples were moderately and low contaminated, respectively. The mean value of PERI with 380.32 implied that the agricultural soils of the study area could be classified of high ecological risk. The spatial distribution of content of the elements showed that Cd had high spatial variability.

Conclusions

Although in the short run, the contents of the elements found in the agricultural soil samples may not be alarming for agricultural production and consequently human health, signals it can be observed especially for Cd in the long term due to the impact of anthropogenic activities that lead to the discharge of this element to the environment and can result in its accumulation in agricultural soils. In conclusion, as it is expected that the metal inputs increase in the future, it is recommended that plant analyses be included in the future studies for determining the impact of the amount of bioavailable metals.

中文翻译：

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农业土壤中砷和部分重金属的分析、空间分布和生态风险评估，案例研究：伊朗南部

 目的

本研究测定了伊朗南部埃格利德县农业土壤中砷、镉、铬、铜、铅和锌的含量，以评估土壤污染和潜在生态风险指数（PERI）以及这些元素的空间分布。元素。

 方法

从100个采样站总共采集了100个表土样本。在实验室中，酸消解后，使用 ICP-OES 测定土壤样品中的元素含量。然后，使用各种指数特别是Igeo、PI、IPI、PLI和PERI评估土壤污染和土壤生态风险。此外，土壤样本中研究元素的空间分布图是通过ArcGIS软件（10.4）使用克里格插值技术绘制的。

 结果

根据结果​​，样品中元素的平均含量（mg/kg）分别为：As、Cd、Cr、Cu、Pb 和 Zn，分别为 1.85、2.80、19.04、19.35、7.17 和 38.77。砷和铜含量与背景值相当，而镉含量则高于相应的背景值。主成分分析(PCA)和层次聚类分析(HCA)结果表明Cd有人为来源；而其他元素则源自天然来源。 As、Cd、Cr、Cu、Pb和Zn的污染指数（PI）值变化范围为0.45~1.49、0.52~32.09、0.096~0.33、0.36~1.35、0.18~0.32和0.23~1.59，平均值为0.23~1.59。分别为 0.92、12.17、0.21、0.68、0.21 和 0.96。样品的综合污染负荷指数（PLI）平均值为0.84，表明土壤样品分别有65%和35%被中度污染和低度污染。 PERI 平均值为 380.32，表明研究区农业土壤可归类为高生态风险。元素含量的空间分布表明Cd具有较高的空间变异性。

 结论

尽管从短期来看，农业土壤样品中发现的元素含量可能不会对农业生产和人类健康产生影响，但从长远来看，由于人类活动的影响，可以观察到这些元素，尤其是镉。将该元素排放到环境中，并可能导致其在农业土壤中积累。总之，由于预计未来金属投入量会增加，建议在未来的研究中纳入植物分析，以确定生物可利用金属量的影响。