| 地质高背景区土壤-水稻系统重金属含量特征与综合质量评价 |
| 摘要点击 1193 全文点击 163 投稿时间：2024-02-23 修订日期：2024-04-07 |
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| 中文关键词 地质高背景区 土壤-水稻系统 重金属（HMs） 生物有效性 综合质量影响指数 |
| 英文关键词 high geological background area soil-rice systems heavy metals（HMs） bioavailability comprehensive impact index |
| 作者 | 单位 | E-mail | | 余飞 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038 | yfcags@126.com | | 张风雷 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038
重庆大学资源与环境科学学院, 重庆 400044 | | | 蒋玉莲 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038 | | | 王锐 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038 | | | 张云逸 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038 | | | 余亚伟 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038 | | | 钟克强 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038 | | | 朱世林 | 重庆市地质矿产勘查开发局川东南地质大队, 重庆土地质量地质调查重点实验室, 重庆 400038 | |
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| 中文摘要 |
| 为了解地质高背景区土壤-水稻系统重金属含量与污染状况,在重庆市东南部采集土壤和水稻籽实样品200套,分析测试了土壤和水稻籽实中重金属含量及赋存状态,利用综合影响指数（IICQ）对土壤-水稻中重金属进行了综合质量评价,并分析了土壤-水稻系统Cd等重金属超标的主要影响因素. 结果表明,土壤中As、Cd、Cr、Hg和Pb平均值均高于重庆市表层土壤背景值和中国表层土壤平均值,土壤重金属富集效应明显. 与农用地土壤风险筛选值相比,研究区土壤中Cd、Hg、As和Pb均存在不同程度的超标,Cd和Hg超标率达82.0%和22.5%；水稻籽实中有41件样品Cd含量超过GB 2726-2022中的标准限值,超标率为20.5%,土壤与农作物Cd等重金属污染评价结果存在较大差异. 随着土壤pH的增加,土壤中Cd的含量平均值逐渐增加,但水稻籽实中Cd的含量平均值降低了0.245 mg·kg-1,超标率降低了42.14%. 水稻籽实中Cd含量与土壤Cd离子交换态、水溶态呈显著相关,土壤pH越高,土壤中生物有效组分占比越低,土壤pH是影响研究区水稻安全的主要因素. 综合质量评价结果显示研究区以中度和重度污染为主,但水稻籽实大多处于清洁状态,少数呈轻微污染,无轻度及以上污染. pH>7.5的碱性地区,水稻基本安全；pH<5.5以下强酸性土壤,水稻籽实超标率达45%,建议施用生石灰或钙质土壤调理剂,改善土壤酸化问题,降低Cd生物有效组分的活性,降低水稻等农产品的超标率. |
| 英文摘要 |
| Heavy metals （HMs） pollution in agricultural soil-rice systems has attracted worldwide attention as it directly threatens regional ecological security and human health. To understand the heavy metal pollution of agriculture soil and rice in the high geological background areas, a total of 200 paddy soil and rice samples were collected in southeast Chongqing. The concentrations of arsenic （As）, cadmium （Cd）, chromium （Cr）, copper （Cu）, mercury （Hg）, nickel （Ni）, lead （Pb）, and zinc （Zn） in paddy soil and rice were analyzed. The comprehensive impact index （IICQ） was used to evaluate the quality of heavy metals in soil-rice. The results showed that the mean concentrations of As, Cd, Cr, Hg, and Pb in soil were higher than their corresponding background values of Chongqing soil and the average values of Chinese surface soil, indicating the accumulation of HMs enrichment of these metals in the paddy soils. Compared with China's soil environmental quality standard of agricultural land （GB 15618-2018）, only 20.5% of rice samples containing Cd exceeded the national food safety standard （GB 2762-2022）, though the Cd and Hg sample contamination rates of the sampling sites were 82% and 22.5%, respectively. The evaluation results of heavy metal pollution, such as Cd in soil and crops, were quite different. With the increase in soil pH value, the average content of Cd in the soil gradually increased, but the average content of Cd in rice seeds decreased by 0.245 mg·kg-1, and the excess rate of rice seeds decreased by 42.14%. The Cd content in rice seeds was significantly correlated with the Cd ion exchange state and water-soluble state in the soil. The higher the soil pH value, the lower the proportion of bioactive components in the soil, and the pH of the soil was the main factor affecting the safety of rice in the study area. The comprehensive quality evaluation results showed that moderate and severe pollution were the main pollution levels in the study area, but most of the rice seeds were in a clean state, a few were slightly polluted, and none showed mild or above pollution. The basic safety of rice was in the alkaline area with a pH>7.5. In strongly acidic soil with pH<5.5 and below, the excess rate of rice seeds could reach 45%. Moreover, it is recommended to apply quicklime or calcareous soil conditioner to improve soil acidification, reduce the activity of Cd bioactive components, and improve the safety of rice and other agricultural products. |
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