| 广西不同成土母质区土壤-作物重金属污染评价及管控建议 |
| 摘要点击 2301 全文点击 443 投稿时间：2023-08-31 修订日期：2023-12-04 |
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| 中文关键词 成土母质 土壤重金属 生物有效性 综合质量影响指数 风险管控 |
| 英文关键词 parent material soil heavy metals bioavailability comprehensive quality impact index risk management and control |
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| 中文摘要 |
| 为了研究不同成土母质区土壤和作物重金属污染情况及影响因素,为耕地分类管控提供依据,以广西东南部兴业县为研究区,共采集土壤表层样品1 326件,作物籽实-根系土样品46套,对比分析了4种成土母质土壤-作物系统中重金属的富集特征,研究了水稻吸收Cd的影响因素,采用综合质量影响指数法对研究区的土壤和农作物开展污染评价,并根据评价结果提出耕地安全利用建议. 结果表明,4种成土母质区中仅碳酸盐岩母质区土壤中各重金属元素均表现出明显富集状态,其中以Cd元素富集现象较突出. 参照《食品安全国家标准 食品中污染物限量》（GB 2762-2022）,水稻籽实重金属Cd的超标率为35.7%,其余重金属均未超标. 不同成土母质区水稻重金属Cd的生物富集系数大小依次为：第四系沉积物区>碳酸盐岩母质区>碎屑岩母质区>花岗岩母质区. 水稻中Cd的富集受到土壤pH和CaO的影响,当土壤pH值在5.5~6.5范围时,水稻籽实Cd的含量和超标率大幅上升. 土壤-作物重金属污染评价结果显示研究区整体重金属风险较高,清洁、 轻微污染、 轻度污染、 中度污染和重度污染的占比分别为23.91%、 10.87%、 17.39%、 17.39%和30.43%,轻度污染及以上均存在农产品超标. 结合综合质量影响指数分布情况和不同成土母质污染特征,针对性地提出了分类管控建议,可为受污染耕地安全利用工作的开展提供思路. |
| 英文摘要 |
| To study the heavy metal pollution and influencing factors of soils and crops in different parent material areas and provide the basis for the classification and control of cultivated land, a total of 1 326 soil surface samples and 46 crop seed-root soil samples were collected from Xingye County in the southeast of Guangxi. The enrichment characteristics of heavy metals in the soil-crop system of four soil-forming parent materials were compared and analyzed, and the influencing factors of Cd absorption by rice were studied. The comprehensive quality impact index method was used to evaluate the soil and crops in the study area, and the safe use of cultivated land was proposed according to the evaluation results. The results showed that in the four soil-forming parent material areas, only the carbonate rock parent material area showed obvious enrichment of heavy metals in the soil, especially Cd. According to the "National Food Safety Standard for the Limit of Pollutants in Food" （GB 2762-2022）, the excess rate of heavy metal Cd in rice seeds was 35.7%, and the other heavy metal rates were not exceeded. The bioconcentration coefficient of heavy metal Cd in rice from different parent material areas was as follows： quaternary sediment area > carbonate parent material area > clastic parent material area > granite parent material area. The enrichment of Cd in rice was affected by soil pH and CaO. When the soil pH value was in the range of 5.5-6.5, the Cd content and exceeding rate of rice seed increased significantly. The evaluation results of soil-crop heavy metal pollution showed that the overall heavy metal risk in the study area was high, and the proportions of clean, mild, light, moderate, and heavy pollution were 23.91%, 10.87%, 17.39%, 17.39%, and 30.43%, respectively. Combined with the distribution of the comprehensive quality influence index and the pollution characteristics of different parent materials, the classification and control suggestions were put forward, which provided ideas for the safe utilization of polluted cultivated land. |
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