设施栽培对土壤与蔬菜中PAHs污染特征及其健康风险评价

Concentrations and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons(PAHs) in Soils and Vegetables influenced by Facility Cultivation

利用现场设施栽培试验,研究了大棚内外土壤、蔬菜(生菜、苋菜、空心菜和青菜)及蔬菜生长期内湿沉降样品中16种PAHs的含量特征、可能来源以及对人的健康风险.结果表明,大棚内外蔬菜中PAHs含量平均值分别为99.27 ng·g^(-1)和109.11 ng·g^(-1);棚内外土壤中PAHs含量分别为128.01 ng·g^(-1)和173.07 ng·g^(-1).棚内PAHs含量明显低于棚外,棚内外土壤与蔬菜体内的PAHs均以低环为主.湿沉降颗粒态与溶解态PAHs含量分别为2 986.49 ng·g^(-1)和61.9 ng·L^(-1).通过分析蔬菜对土壤中PAHs的生物富集系数发现蔬菜对低环PAHs富集系数较大.土壤与蔬菜中PAHs主要来源为石油排放和草、木和煤的燃烧;湿沉降颗粒态中PAHs主要来源为油类排放与草、木和煤的燃烧;溶解态主要来源为化石燃料的燃烧和汽油排放.分析终身暴露致癌风险,儿童与成人食用不同种类蔬菜的终身暴露致癌风险值ILCR在10-6~10-4(排除苋菜)之间,都存在潜在致癌风险,棚外蔬菜致癌风险高于棚内,相比较其他3种蔬菜食用苋菜(ILCR<10-6)的致癌风险最低,青菜的终身暴露风险ILCR>10-5,有较高的致癌风险.

The concentrations,sources,and health risks of 16 United States Environmental Protcction Agency（ USEPA） priority polycyclic aromatic hydrocarbons（ PAHs） in vegetables（ leafy lettuce,amaranth,water spinach,and Shanghai green）,in soils inside and outside the vegetable greenhouse,and in wet deposition were investigated by conducting an experiment on facility cultivation. The results showed that the average concentrations of total PAHs in vegetables and soils were 99. 27 ng·g^-1and 128. 01 ng·g^-1in the greenhouse,and 109. 11 ng·g^-1and 173. 07 ng·g^-1out of the greenhouse. The concentrations of PAHs in the greenhouse were lower than those outside and the high ring-PAHs were lower than the low ring-PAHs both inside and outside. The PAH concentrations in suspended particular matter in dissolved phases of wet deposition were 2 986. 49 ng·g^-1and 61. 9 ng·L^-1,respectively. The low rings were easily enriched by the vegetables based on the shoot concentration factors. PAHs in soils and vegetables mainly originated from oil emissions and grass,wood,and coal combustion,while those in suspended particular matter in wet deposition were from petrogenic sources and the combustion of grass,wood,and coal. Petroleum combustion emissions were the main sources of PAHs in dissolved phases. We used the model of incremental lifetime cancer risks to evaluate the health risk of eating these vegetables. There was a potential risk of cancer for both children and adults for all vegetables except amaranth. The carcinogenic risk of vegetables outside the greenhouse was higher than the risk inside. Amaranth had a low carcinogenic risk with the value of incremental lifetime cancer risk lower than 10^-6,while the risk of Shanghai green ranged between 10^-4and 10^-6.