不同栽培环境下豇豆体内多环芳烃源解析及风险评估

Source analysis and risk assessment of PAHs in Vigna unguiculata (Linn.) Walp in different culture environments

为了探讨不同污染特征环境下栽培的蔬菜体内多环芳烃(PAHs)来源及风险,以豇豆[Vigna unguiculata(Linn.)Walp]为材料,检测大棚(试验基地PAHs污染残留区)和大田(距离机动车通道100 m内)栽培的豇豆体内PAHs含量,采用同分异构体比值法分析了其体内PAHs来源,并用生态效应低中值法和苯并(a)芘毒性等效当量法评估了豇豆体内PAHs污染的生态风险,以人群日均暴露量估算了其潜在人体健康风险。结果表明:在16种优控的PAHs中,大棚豇豆体内含有13种,大田豇豆体内含有6种;大棚豇豆体内的PAHs总含量为253.94μg·kg-1,以2～4环为主,其中3环占总含量的64.47%。大田豇豆体内PAHs总含量为80.60μg·kg-1,芴和菲占总含量的69.69%。大棚和大田豇豆体内的二苯并(a,h)蒽毒性当量分别为43.32μg·kg-1和10.85μg·kg-1,其对总的毒性当量贡献率分别为89.38%和88.57%;大棚和大田豇豆的人群健康风险系数分别为2.07×10-6和6.5×10-7。研究表明:大棚豇豆体内PAHs主要源于人为处理残留的PAHs;大田豇豆体内PAHs主要来源于汽油和生物质燃烧污染。大棚豇豆存在一定的生态风险和健康风险,大田豇豆尚不存在PAHs的生态风险和健康风险,但需重视苯并(k)荧蒽、二苯并(a,h)蒽和茚并(1,2,3-c,d)芘等物质的富集作用。

We evaluated the source and risk of polycyclic aromatic hydrocarbons(PAHs)in vegetables cultivated under different pollution conditions using Vigna unguiculata(Linn.)Walp as the study material.PAH contents were detected in Vigna unguiculata(Linn.)Walp planted in a shed(PAH contamination residue area)and field(within100m of a motorway).The PAH source was analyzed by the isomerism method.The ecological risk of PAH pollution in Vigna unguiculata(Linn.)Walp was evaluated using the low median method of ecological effect and toxicity equivalent of pyrene(a)pyrene(TEQBaP).The potential human health risk was estimated by daily pollution human exposure levels.The results showed that,of the16types of PAH,13were found in samples planted in the shed and6were found in those planted in the field.The total PAH content in the shed plants was253.94μg·kg-1,which mainly contained2~4rings;3-ring PAHs accounted for64.47%.The total PAH content in the field plants was80.60μg·kg-1,while fluorene and phenanthrene accounted for69.69%.The TEQBaP of dibenzo(a,h)anthracene in Vigna unguiculata(Linn.)Walp planted in the shed and field were43.32μg·kg-1and10.85μg·kg-1,respectively,which represented89.38%and88.57%of the total TEQBaP.The health risk factors of shed and field plants were2.07×10^-6and6.5×10^-7,respectively.Most PAHs in Vigna unguiculata(Linn.)Walp planted in the shed came from man-made pollution treatment,whereas for those planted in the field,PAHs were mainly derived from gas and biomass burning.Vigna unguiculata(Linn.)Walp planted in the shed exhibited a certain extent ecological risk but those planted in the field showed no risk;however,the enrichment of benzo(k)fluoranthene,dibenzo(a,h)anthracene and indeno(1,2,3-c,d)pyrene is a serious cause for concern.