郭雯婕, 郭含旭, 张耀怡, 高艳鹏, 田恬, 罗斌, 雷纯阳, 阮烨. 长庆油田产油区周边农田重金属分布特征及生态风险评价[J]. 环境与职业医学, 2022, 39(5): 527-531, 538. DOI: 10.11836/JEOM21410
引用本文: 郭雯婕, 郭含旭, 张耀怡, 高艳鹏, 田恬, 罗斌, 雷纯阳, 阮烨. 长庆油田产油区周边农田重金属分布特征及生态风险评价[J]. 环境与职业医学, 2022, 39(5): 527-531, 538. DOI: 10.11836/JEOM21410
GUO Wenjie, GUO Hanxu, ZHANG Yaoyi, GAO Yanpeng, TIAN Tian, LUO Bin, LEI Chunyang, RUAN Ye. Distribution characteristics and ecological risk assessment of heavy metals in farmland around Changqing Oilfield[J]. Journal of Environmental and Occupational Medicine, 2022, 39(5): 527-531, 538. DOI: 10.11836/JEOM21410
Citation: GUO Wenjie, GUO Hanxu, ZHANG Yaoyi, GAO Yanpeng, TIAN Tian, LUO Bin, LEI Chunyang, RUAN Ye. Distribution characteristics and ecological risk assessment of heavy metals in farmland around Changqing Oilfield[J]. Journal of Environmental and Occupational Medicine, 2022, 39(5): 527-531, 538. DOI: 10.11836/JEOM21410

长庆油田产油区周边农田重金属分布特征及生态风险评价

Distribution characteristics and ecological risk assessment of heavy metals in farmland around Changqing Oilfield

  • 摘要: 背景 随着国家能源开发布局的变化,庆阳地区出现了石油开采和农业并重的局面,如果不引起重视,极易造成当地土壤污染。

    目的 评价长庆油田主产区周边农田土壤重金属的分布特征、可能来源及生态风险。

    方法 采集长庆油田主产区周边的庆阳市正宁县、镇原县、庆城县三县农田土壤样本60份,按GB15618—2018《土壤环境质量 农用地土壤污染风险管控标准(试行)》的方法检测农田土壤重金属铅(Pb)、汞(Hg)、铬(Cr)、镉(Cd)、砷(As)的质量分数(后称:含量),以甘肃省土壤背景值作为计算污染指数的分母,采用单因子污染指数(Pi)法、内梅罗综合污染指数(PN)法和潜在生态风险指数法评价农田土壤5种重金属的污染及生态特征。

    结果 长庆油田周边农田土壤5种重金属中Pb、As、Hg以及庆城县Cr、Cd和正宁县Cd水平超过甘肃省土壤背景值,但均低于国家土壤环境质量标准。单因子污染指数(Pi)分别为Hg(2.14)、Pb(1.24)、As(1.13)、Cr(0.78)、Cd(0.67),提示Hg属于中污染,Pb和As属于轻污染,Cd和Cr为未污染状态;内梅罗综合污染指数(PN)分别为Cr(0.92)、Cd(1.08)、As(1.20)、Pb(1.68)、Hg(3.85),提示Cr为尚清洁,Cd、Pb和As属于轻度污染,Hg属于重度污染。镇原县Hg、Cd和庆城县Hg含量值的变异系数分别为60.00%、50.00%和50.00%,均大于50%,提示所在地相应重金属的污染受人为影响较大。农田土壤中Pb、Cr、Cd、As和Hg 5种重金属潜在生态风险指数(Er)分别为6.20、1.55、20.05、11.28和81.64,即Hg属于强生态风险水平,其余4种重金属属轻微生态风险水平;综合潜在生态风险(RRI)为124.48,结合Hg的潜在生态风险指数,认为当地农田土壤中5种重金属的综合潜在生态风险属强生态风险水平。

    结论 长庆油田主产区农田土壤中5种重金属水平均值虽未超过国家土壤环境质量标准,但已超过甘肃省土壤相应元素的背景值,且存在人为影响的迹象和不同程度的潜在生态风险。

     

    Abstract: Background With the change of the national energy development layout, Qingyang has seen a situation where oil exploitation and agriculture go hand in hand, which may lead to local soil pollution if not taken seriously.

    Objective To evaluate the distribution characteristics, possible sources, and ecological risks of heavy metals in farmland soils around the main production areas of Changqing Oilfield.

    Methods A total of 60 farmland soil samples were collected from Zhengning County, Zhenyuan County, and Qingcheng County of Qingyang City, and the contents of heavy metals such lead (Pb), mercury (Hg), chromium (Cr), cadmium (Cd), and arsenic (As) in farmland soil were detected according to GB 15618-2018 Soil environmental quality—Risk control standard for soil contamination of agricultural land(on trial). The soil background value of Gansu Province was used as the denominator in the calculation of pollution index, and the pollution characteristics and ecological characteristics of selected five heavy metals in farmland soil were evaluated by single-factor pollution index (Pi), Nemerow comprehensive pollution index (PN), and potential ecological risk index.

    Results The levels of Pb, As, and Hg in farmland soils around Changqing Oilfield, the levels of Cr and Cd in Qingcheng County, and the level of Cd in Zhengning County were higher than the corresponding soil background values of Gansu Province, but lower than the national soil environmental quality standard. The single-factor pollution indexes (Pi) were: Hg, 2.14; Pb, 1.24; As, 1.13; Cr, 0.78; Cd, 0.67, which indicated that Hg were graded as moderate pollution, Pb and As were slight pollution, and Cd and Cr were not polluted. The Nemerow comprehensive pollution indexes (PN) were: Cr, 0.92; Cd, 1.08; As, 1.20; Pb, 1.68; Hg, 3.85, which indicated that Cr was graded as no pollution, Cd, Pb and As were mild pollution, and Hg was severe pollution. The variation coefficients of Hg and Cd in Zhenyuan County and that of Hg in Qingcheng County were 60.00%, 50.00%, and 50.00%, respectively, which were all greater than 50%, indicating that the pollution of above heavy metals in the location was subject to human activities. The potential ecological risk indexes (Er) of Pb, Cr, Cd, As, and Hg were 6.20, 1.55, 20.05, 11.28, and 81.64, respectively, indicating that Hg was graded as strong ecological risk, and the other four heavy metals were mild ecological risk. The comprehensive potential ecological risk index (RRI) was 124.48. Combined with the potential ecological risk index of Hg, the comprehensive potential ecological risk of the five heavy metals in local farmland soils was considered to be at a strong ecological risk level.

    Conclusion Although the average values of selected five heavy metals in farmland soils surrounding the main production areas of Changqing Oilfield are qualified with the national soil environmental quality standards, they exceed corresponding soil background values of Gansu Province, and there are signs of human influence and potential ecological risks of different degrees.

     

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