| 高强度运输活动影响下承德钒钛磁铁矿集区土壤重金属生态风险与来源解析 |
| 摘要点击 470 全文点击 63 投稿时间：2024-04-15 修订日期：2024-06-10 |
| 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 钒钛磁铁矿 重金属污染 土壤 道路降尘 正定矩阵因子分解（PMF） 承德 |
| 英文关键词 vanadium-titanium magnetite heavy metal pollution soil road dust positive matrix factorization（PMF） Chengde |
|
| 中文摘要 |
| 以承德伊逊河红旗-大庙钒钛磁铁矿小流域为例,采集895件表层土壤（0~20 cm）与5件道路降尘样品. 通过地累积指数、生物有效性风险编码、综合生态风险指数与改进内梅罗综合生态风险指数评价了土壤重金属累积程度与生态风险,结合主成分、相关聚类、冗余分析与GIS空间分析,探究了土壤重金属空间分异对交通路网、土地利用与成土母质类型环境因子的响应特征,采用正定矩阵因子分解（PMF）模型定量解析了土壤重金属污染来源. 结果表明,表层土壤Cu、Cr、Cd、Ni、Pb和Zn超农用地土壤污染风险筛限值（GB 15618-2018）比例分别为5.70%、2.79%、1.01%、0.67%、0.11%和0.11%. 土壤重金属地累积程度由强至弱为：Cu>Ti>Cr>V>Co>Ni>Cd>Zn>Mn>As>Hg>Pb,Cu地累积指数平均值为1.23,达中等累积水平. 在路网200 m范围内,Cu、Zn、Cr、Mn、V、Ti、Co和Ni累积程度随距路网距离增大逐渐减弱；Cd累积程度在路网25~800 m范围内较为稳定,Pb、Hg和As地累积程度在距路网200 m处达到最高. 重金属风险评估编码值（RAC）由强至弱为：Cd>Mn>Ni>Zn>Hg>Co>Pb>Cu>As>Cr>V>Ti,Cd元素表现出高生物活性,RAC平均值达46.45%,其它元素总体属低风险-无风险水平. 重金属潜在综合生态风险RI值范围为51.48~1 152.39,平均值为131.12, 1.01%样品达强生态风险；内梅罗综合潜在生态风险指数（mNIER）范围为10.32~745.57,平均值达32.85, 97.43%样点属轻风险与中度风险. 高强度交通运输贡献了表层土壤44.82%、33.45%、32.27%和24.35%的Pb、Hg、Cd和Zn；成土母质自然源、钒钛磁铁矿床风化源、工业排放与燃煤降尘及矿区二次扬尘混合源、农业生产生活源、交通活动源对12种重金属的总体贡献率分别为27.46%、21.12%、19.29%、17.05%和15.08%. |
| 英文摘要 |
| A total of 895 surface soil samples （0-20 cm） and five road-dust samples were collected in a typical vanadium-titanium magnetite mining area of Hongqi-Damiao catchment in the Chengde City and analyzed for 12 heavy metals （Cu, Ni, Cd, Cr, Pb, Zn, Hg, V, Ti, Mn, As, and Co） and their chemical speciation. The accumulation and ecological risk characteristics of soil heavy metals （HMs） were clarified by geological accumulative index, potential ecological risk index （RI）, risk assessment coding （RAC）, and modified Nemerow integrated ecological risk index （mNIER）. Multiple statistical methods including principal component analysis, correlation analysis, cluster analysis, redundancy analysis, and GIS spatial analysis were used to investigate the spatial variation response of soil HMs to the environmental impact factors （distance to the road network, land use, and soil parent material types）. The sources of HMs were quantitatively analyzed using a positive matrix factorization （PMF） model. The results showed that the over-standard rates of Cu, Cr, Cd, Ni, Pb, and Zn were 5.70%, 2.79%, 1.01%, 0.67%, 0.11%, and 0.11%, respectively, in comparison to China's soil environmental quality standard risk screening values （GB15618-2018）. The average accumulation index of soil HMs followed the order of Cu>Ti>Cr>V>Co>Ni>Cd>Zn>Mn>As>Hg>Pb, while the average accumulation index of Cu was 1.23 and categorized as moderate accumulation. The accumulation of Cu, Zn, Cr, Mn, V, Ti, Co, and Ni gradually decreased within a distance of 200 m, while the content of Cd in soil was relatively stable within the distance from 25 m to 800 m to the road network, and the accumulation index of Pb, Hg, and As in soil was highest at the 200 m buffer zone. The average RAC value of 12 HMs followed the order of Cd>Mn>Ni>Zn>Hg>Co>Pb>Cu>As>Cr>V>Ti. The average RAC value of the Cd element was 46.45%, showing high biological activity, while the bioavailability RAC value of other elements was generally categorized as low-risk or risk-free level. The potential ecological risk of HMs in soil was relatively low with the RI value range between 51.48 to 1 152.39 （average of 131.2） and the mNIER value range between 10.32 to 745.57, with an average value of 32.85, in which 97.43% of the samples were classified as light to moderate risk. Based on the PMF model, 44.82%, 33.45%, 32.27%, and 24.35% of Pb, Hg, Cd, and Zn in surface soil were contributed by intensive transportation activities, respectively. The main sources of 12 HMs in the study area were the combined sources of natural sources （soil parent materials）, weathering sources of V-Ti-Fe-P deposits, dust deposition from industrial and mining activities and coal combustion, agricultural sources, and traffic sources, with their contribution rates of 27.46%, 21.12%, 19.29%, 17.05%, and 15.08%, respectively. |
|
|
|
