公路旁土壤中重金属污染分布及潜在生态危害的研究

[目的]研究公路旁土壤中重金属污染的分布及潜在生态危害。[方法]以319国道龙岩市新罗区路段为研究区,对耕作土采样,用原子吸收光谱法和分光光度法分析土壤中重金属Cd、Pb、Cu、Zn和Cr含量,并与对照区比较,同时采用Lars Hakanson指数法评价重金属的潜在生态危害。[结果]研究区表层土壤cd[(1.48±0.60)mg/kg]、Pb[(160.17±55.99)mg/kg]、cu[(38.44±12.16)mg/kg]、Zn[(80.35±6.60)mg/kg]、Cr[(79.50±23.58)mg/kg]含量显著高于对照区(P<0.001),Cd和Pb为重度污染(100％),Cu和Cr为轻微污染(分别占监测点位的55.8％和35.3％);土壤对重金属元素的吸收及污染程度:Pb>Cd>Cu>Cr>zn。潜在生态危害综合指数为253.0,主要污染为Cd,达到很强的生态危害,其次是Pb、Cu、Cr和Zn,均为轻微生态危害;潜在生态危害地带自公路起向其两侧扩散范围约为150 m。[结论]公路旁土壤中重金属以Cd、Pb污染为主,属于中等生态危害,污染物主要来源于机动车辆燃料和轮胎中所含微量重金属成分。

Study on the Heavy Metal Contamination in Roadside Soil and the Ecological Hazard

[Objective] To study the distribution of the heavy metal contamination in roadside soil and the potential ecological hazards. [Methods] The levels of heavy metals (Cd, Pb, Cu, Zn and Cr) in farmland soil along No. 319 Road in Xinluo, Longyan were analyzed by atomic adsorption spectro-photometry and spectro-photometry. The potential ecological hazards were assessed by Lars Hakanson Index. [Results] The levels of Cd, Pb, Cu, Zn and Cr were 1. 48, 160. 17, 38. 44, 80. 35, 79. 50 mg/kg respectively in the surface soil and higher than those in the control area. The soil was contaminated by Cd (100%) and Pb (100%) and lightly by Cu (55. 8%) and Cr (35. 3%). The adsorptive capacity of soil to the metals and the levels were in the following orders : Pb > Cd > Cr > Cu > Zn. The hazard index was 253. 0. Cd was a main ecological hazard factor, followed were Pb, Cu, Cr and Zn. The contamination zone was distributed along the both roadsides with 150 m width. [Conclusion] The roadside soil was mainly contaminated by Cd and Pb. The medium ecological hazards are caused by the metal contamination. The main contamination sources are trace heavy metals from fume and tires of running vehicles.