| Polycycylic aromatic hydrocarbons?PAHs?are hydrophobic organic compounds,with teratogenicity,carcinogenicity and mutagenicity.PAHs are persistent environmental organic pollutants and widespread in the environment,which are easy to be absorbed by solids,made soil a repository.PAHs are more likely to be absorbed by vegetables and food chain is the major pathway for human exposure to PAHs,ultimately causing a risk to human health.Aquatic vegetables,as a large group of vegetables,play an indispensable role in adjusting people's dietary structure.In this study,three major aquatic vegetables in Guangxi,lotus root,sagittaria trifolia and water chestnut,were taken as the research objects,comparing the PAHs pollution characteristics of aquatic vegetable and terrestrial vegetable and soil,analysis the main sources of PAHs in soil and investigate the health risk assessment of PAHs by vegetables intake.In order to provide basic data and theoretical for the prevention of soil PAHs pollution and the safe production of vegetables.The mainly results are as follows:?1?The concernation ofin soils of aquatic vegetable fields,was higher than those in terrestrial vegetable soils.Mover over The concentrations of five-and six-ring PAHs and seven kinds of carcinogenic PAHs in the aquatic vegetable soil within the study area were significantly higher than those in the terrestrial vegetable soil,the concentrations of two-and three-ring PAHs were lower than those in the terrestrial vegetable soil,the concentrations of four-ring PAHs were not significantly different.most sampling sites at the severe pollution levels.The pollution of the soil in the study area in the medium level.Three different aquatic vegetable soils have the same PAHs pollution patterns,four-and five-ring PAHs was dominatnt,followed by two-and three-ring PAHs,six-ring PAHs was the least.?2?The molecular diagnostic ratios and principal component analysis?PCA?suggests that the main sources of PHAs were vehicle emission and biomass combustion in the soil.The TEQ in aquatic vegetables soil(174.59?g·kg-1)was significant higher than those in the terrestrial vegetables soil(105.54?g·kg-1),both of them were lower than the soil quality indicators of Canada(600?g·kg-1),but potential ecological risks should not be neglected.?3?The concentration of 6-ring PAHs andin edible part of aquatic vegetables were significantly greater than those in terrestrial vegetables.By contrast,the rates of 2 and 3-ring PAHs in terrestrial vegetables were all over 50%,which were all significantly higher than those in aquatic vegetables.The concentration of PAHs in three kinds of aquatic vegetables,lotus root,sagittaria trifolia and water chestnut,was not only trended in an order with 749.02?g·kg-1,652.09?g·kg-1and 629.30?g·kg-1,respectively.At the same time,the proportion of different rings of PAHs in aquatic vegetable was also similar.?4?In edible part of vegetables was mainly contaminated by the low molecular weight of PAHs,for their contents were all higher than those of high molecular weight of PAHs.There was a positive correlation between the contents of 5-ring PAHs?r=0.62,p=0.08?,6-ring PAHs?r=0.54,p=0.06?PAHs andin aquatic vegetables and soils.And there was the same correlation between the contents of 5-ring PAHs?r=0.77,p=0.29?andin terrestrial vegetables and soils,but there was no significant difference between them.?5?The value of ILCR for human being under different ages,which induce by feeding with PAHs-contaminated vegetables,was showed in an order from high to low with child,adult,senior and adolescent.And the value of ILCR for male in adult and senior stages was higher than that of female.Meanwhile,the ILCR value of PAHs in different vegetables,was in an rank with leafy vegetables,fruit vegetables and aquatic vegetables,respectively. |
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