To investigate the vertical changes of toxic elements in Jurassic sediments, sampling was performed in four sites. Samples were collected from sandstones and mudstones/marls and analyzed for some toxic elements (Cu, Pb, Zn, As, Ni and V). Results exhibited that the sediment grain size played a significant role in controlling the concentrations of the toxic elements in the sediments. The mean toxic element contents of mudstones/marls were higher than those of sandstones (except Cu). The contamination level of toxic elements was detected by enrichment factor (EF), geo-accumulation index (I_geo), potential ecological risk index (Eⁱ_r), pollution index (Pi) and united pollution index (PI_n). The low EF, I_geo, Eⁱ_r, Pi and PI_n for Cu, Pb, Zn, Ni, V in the sandstones and Cu, Zn, Ni in the mudstones/marls exhibited an absence of clear these elements pollution. The high EF, Eⁱ_r, Pi and PI_n for As (9.7, 73, 7 and 29, respectively, as mean values) in the sandstones and for As (49.3, 222, 22 and 75, respectively, as mean values) Pb (8.8, 24, 5 and 19, respectively, as mean values), V (8.3, 15, 7 and 39, respectively, as mean values) in the mudstones/marls indicated significant contamination. Additionally, according to the potential ecological risk (RI) values, the sandstones had low potential ecological risk for the toxic elements (RI < 150) and the mudstones/marls had moderate potential ecological risk (150 ≤ RI ≤ 300). The potential ecological risk As, Pb, V (especially As) were higher in urban areas than in agricultural activities. Therefore, the source of As, Pb, V could be gasoline combustion, burning coal and vehicle exhausts. The contents of these elements generally increased from bottom to top of the measured stratigraphic sections, which indicated transported by atmospheric conditions.

为了调查侏罗纪沉积物中有毒元素的垂直变化，在四个地点进行了采样。从砂岩和泥岩/泥灰岩中收集样品，并分析一些有毒元素（铜，铅，锌，砷，镍和钒）。结果表明，沉积物粒径在控制沉积物中有毒元素的浓度方面起着重要作用。泥岩/泥灰岩的平均有毒元素含量高于砂岩（铜除外）。通过富集因子（EF），地质累积指数（I _geo），潜在生态风险指数（E ⁱ _r），污染指数（Pi）和联合污染指数（PI _n）检测有毒元素的污染水平。低EF，我砂岩中Cu，Pb，Zn，Ni，V和泥岩/泥灰岩中Cu，Zn，Ni的_geo，E ⁱ _r，Pi和PI _n缺乏明显的这些元素污染。高EF，E ⁱ _r，Pi和PI _n对于砂岩中的砷（分别为平均值9.7、73、7和29）和砷（分别为平均值分别为49.3、222、22和75）Pb（分别为8.8、24、5和19）泥岩/泥灰岩中的V（平均值分别为8.3、15、7和39）表示存在严重污染。此外，根据潜在的生态风险（RI）值，砂岩对有毒元素的潜在生态风险较低（RI <150），而泥岩/泥灰岩具有中等的潜在生态风险（150≤RI≤300）。潜在的生态风险As，Pb，V（尤其是As）在城市地区高于农业活动。因此，As，Pb，V的来源可能是汽油燃烧，燃煤和汽车尾气。