| 黑土区城郊耕地重金属污染空间扩散机制 |
| 摘要点击 2673 全文点击 793 投稿时间：2022-10-25 修订日期：2022-12-18 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 城郊地区 黑土耕地 重金属 源头防控 空间扩散机制 |
| 英文关键词 peri-urban area black soil cropland heavy metal source control spatial diffusion mechanism |
|
| 中文摘要 |
| 城郊复杂环境条件下的耕地土壤重金属污染空间扩散机制是落实土壤污染源头防控和保障黑土地质量安全的基础.针对以往溯源研究中污染源头难定位和扩散趋势不明确等问题，以长春市城郊地区为例，以耕地土壤As、Pb、Hg和Cd元素为研究对象，采用近邻传播（AP）算法和空间自回归的扩散格局-驱动因素组合分析法尝试揭示黑土区城郊耕地重金属污染空间扩散机制.结果表明，ω（As）和ω（Cd）均值分别为39.35mg ·kg-1和0.183 mg ·kg-1，累积水平较高.内梅罗指数显示研究区有52.38%的耕地已出现轻度污染.AP算法识别出As存在3个影响幅度相似的潜在污染源地，均位于远离城市的典型农耕区；Pb元素的2个潜在污染源地集中分布于范家屯镇附近的工业区；Hg和Cd元素的扩散格局复杂，尤其是Cd元素，呈现多地并发的污染扩散特征.空间滞后模型表明，As元素的空间扩散格局和农药施用强度有关；Cd元素主要受土壤类型和设施农业布局的制约；Pb元素受区域城镇化和工业化发展的影响；Hg元素和区域污染迁移条件相关.污染调蓄功能未对4种元素的空间扩散格局产生显著影响.研究丰富了耕地重金属污染的空间分析理论和方法，对落实城郊黑土地的污染源头防控具有科学意义. |
| 英文摘要 |
| The spatial diffusion mechanism underlying cropland heavy metal contamination in a complex peri-urban environment provides a crucial basis for controlling soil contamination from the source and also for ensuring the quality of black soil croplands. However, previous studies have struggled to locate the contamination sources or trace their diffusion trajectories in space. In this regard, representative peri-urban croplands in the black soil region were selected as a case, and soil As, Pb, Hg, and Cd were deemed as the main research objects. Moreover, an affinity propagation algorithm and spatial autocorrelation regression were adopted to measure the contamination patterns and identify the major determinants, in an attempt to reveal how heavy metals are diffused in the peri-urban cultivated area. The results indicated that ① the average concentrations of soil As and Cd were 39.35 mg·kg-1 and 0.183 mg·kg-1, respectively, which exhibited heavier accumulation in the study area. The Nemerow index indicated that there were 52.38% of croplands indicating slight contamination. ② The affinity propagation algorithm identified three potential sources with a similar impact extent for As, which were situated in the typical cultivated area. Both of the two identified potential sources for Pb were situated in close proximity to Fanjiatun Town. The diffusion patterns for Hg and Cd were complex, particularly for the latter, of which the potential sources were scattered in multiple places. ③ The spatial lag model indicated that the distributions of As and Cd were mainly controlled by the intensive agriculture in peri-urban areas, among which As was related to the application of herbicide and Cd was related to the distribution of protected agriculture. Pb was mainly influenced by urbanization and industrialization, whereas Hg was found to be associated with the migration conditions of the soil. However, the regulating function provided by either croplands or their nearby environment did not play an important role in determining the diffusion patterns of heavy metals. The present study enriches the theory and methods for the spatial analysis of cropland heavy metal contamination and is significant for controlling contamination from the source in peri-urban croplands in the black soil region. |
|
|
|
