海南胡椒种植基地土壤重金属评价及来源分析

在对海南省主要胡椒种植区-文昌、琼海两市种植地土壤重金属含量调查的基础上,采用单项污染指数法和综合污染指数法,结合绿色食品产地环境技术条件及土壤环境质量二级标准,对其重金属含量现状进行了评价;然后结合深层土壤、母质岩石样品及海南岛1:25万多目标区域地球化学调查成果,对其土壤重金属来源进行了综合分析。结果表明,相对所选标准,沉积砂岩区(F11~F13)、第四系松散沉积物区(F7、F14)和花岗岩区一种植地(F9)均符合绿色食品产地要求。玄武岩区(F1~F6)土壤Cu、Cr、Ni超标,花岗岩区另一种植地(F8)和变质岩区(F10)土壤Pb、As超标。综合分析结果显示,胡椒基地土壤环境质量整体良好,成土母质是土壤中重金属元素的主要控制因素,但部分种植地浅层土壤中Cd、Pb、As等重金属元素已受到人类活动的影响。

Source Analysis and Evaluation of Soil Heavy Metals in Pepper Fields in Hainan Province

According to the investigation of heavy metal contents in soils in pepper fields in Wen-chang and Qiong-hai,main pepper bases,in Hainan Province,the status of heavy metals in the soils was evaluated.The evaluation was made through adopting single-factor pollution index method,synthesis pollution index method and green food-technical conditions for environmental of area and the grade Ⅱ standard for soil environmental quality.Then the source of heavy metals in pepper fields was discussed by combining to the deep soil samples,soil parent rock samples and the results of 1:25,000 multi-target regional geochemical surveys in Hainan Island.The results indicated that Ni,Cr and Cu were the main heavy metal pollution factors in the six fields(F1-F6) weathered from basalt.Pb and As sub-standard existed in the two pepper fields(F8 and F10) weathered from granite and metamorphic rock.The rest six fields met green food-technical conditions for environmental of area,which are weathered from sedimentary sandstone(F11-F13),loose sediment of Quaternary(F7 and F14) and granite(F9).Basing on systems analysis,though Cd,Pb,As and other heavy metals,caused partly by the impact of Human activities,were enriched in the surface soil of certain pepper fields,but the soil parent material types were the main factors controlling concentrations of heavy metals in the soils.