海南岛北部种植园土壤中多环芳烃的质量分数、 来源及生态风险

Contents,sources and ecological risk assessment of polycyclic aromatic hydrocarbons(PAHs)in agricultural soils of plantations in northern Hainan Island

海南岛是我国主要的热带农作物种植基地,对海南岛种植园土壤污染物评估具有重要意义。对海南岛北部种植园土壤中的16种多环芳烃(PAHs)质量分数、来源及生态风险进行评估。使用气相色谱-质谱联用技术对咖啡、香蕉、山药、甘蔗、橙子、百香果和石榴种植园中100件表层土壤样品进行PAHs质量分数测定。结果表明,研究区种植园土壤平均∑_(16)PAHs为37.6 ng/g,低于我国土壤背景值和荷兰无污染土壤限值(<200 ng/g)。三环、四环和五环PAHs为主要组成成分,分别占据∑_(16)PAHs质量分数的25.8%,26.8%和23.5%。源识别显示,种植园内PAHs主要来自机动车尾气排放,部分来自石油产品的泄露及煤和生物质的低温燃烧。生态风险评价结果显示,等效毒性当量∑_(16)BaP _(eq)低于国家标准,表明土壤中PAHs污染物水平处于可接受范围。

Hainan Island is the main planting base of tropical plants in China.Evaluating the level of soil pollution in this area has a great significance.In this study,we assessed the contamination levels,sources and ecological risk of 16 priority polycyclic aromatic hydrocarbons(PAHs)in agricultural soils of northern Hainan Island.A total of 100 surface soil samples were collected from plantations(coffee,banana,yam,sugarcane,orange,passion fruit and guava)and analyzed for PAHs concentration using gas chromatography equipped with a mass spectrometry detector(GC-MS).The average of∑_(16)PAHs from plantation soil was 37.6 ng/g,which was below the background of national soil and the no pollution limit of 200 ng/g determined by Netherlands.Three-,four-and five-ring PAHs were dominant components,accounting for 25.8%,26.8%and 23.5%of the total PAHs,respectively.Source analysis suggested that PAHs of soil in these plantations were mainly derived from the exhaust gas of locomotives and partially from oil spill as well as low temperature combustion of coal and biomass.In ecological risk assessment,the benzo(a)pyrene equivalent concentration(∑_(16)BaP _(eq))presented a much lower level than the guideline values announced by Chinese Environmental Protection Agency,demonstrating that the PAHs contamination level in solis was acceptable.