长江中游赤壁段农业用地多环芳烃来源解析

Distribution and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Different Agricultural Lands in Chibi along the Middle Reaches of Yangtze River

该文利用气相色谱-质谱联用法检测了长江中游沿岸赤壁市太平口村不同农业用地的多环芳烃的含量、组成,借助异构体比值法及生态风险评价法对这些农田土壤多环芳烃(PAHs)进行了源解析及生态风险评价。结果显示,种植玉米、大豆、棉花、水稻和茶树的土壤中检测的16种优控PAHs含量在91.55~543.02 ng/g之间,其中种植玉米、大豆、棉花、水稻4种作物的土壤PAHs以中高环数为主且种植水稻土壤含量最高,可能由水稻种植过程中灌溉活动贡献。种植茶树土壤含量最低且以低环数PAHs为主,可能和茶树种植的地理位置和PAHs扩散作用相关。源解析表明,这些农业用地土壤中PAHs主要来源是燃烧源,比如木材秸秆燃烧、煤炭燃烧等。生态风险评价表明,长江中游沿岸赤壁市太平口村农田土壤存在一定的PAHs致癌风险,茚并[123-cd]芘和苯并[a]芘是主要的致癌化合物。通过和长江流域及其他地区土壤PAHs对比发现,在太平口村实施的秸秆焚烧等管控措施对减少PAHs在长江沿岸农田土壤的积累有一定的积极作用。

The concentrations of PAHs in different agricultural lands in Taipingkou Village,Chibi City along the middle reaches of the Yangtze River were detected by gas chromatograph-mass spectrometry.The source apportionment and ecological risk assessment of PAHs in the farmland were carried out by means of isomer ratio method and ecological risk assessment method.The results showed that the content of 16 kinds of optimized PAHs detected in the soil planted with corn,soybean,cotton,rice and tea trees ranged from 91.55 to 543.02 ng/g.The soils of corn,soybean,cotton and rice were dominated by medium and high cyclic PAHs.And the concentrations of PAHs in rice soils were the highest which may be contributed by irrigation activities during rice planting.The concentrations of PAHs in tea soils were the lowest and dominated by low cyclic PAHs which may be related to the geographical location of tea tree planting and the diffusion of PAHs in air.Source analysis shows that the main sources of PAHs in the agricultural soils are combustion sources,such as wood straw burning and coal burning.The ecological risk assessment showed that PAHs carcinogenic risk existed in the farmland soil of Taipingkou Village in Chibi City along the middle reaches of the Yangtze River,and InP and BaP were the main carcinogenic compounds.By comparing with PAHs in the Yangtze River basin and other areas,it was found that straw burning and other control measures implemented in Taipingkou Village have a certain positive effect on reducing the accumulation of PAHs in the farmland soil along the Yangtze River.