珠三角地区稻田土壤和谷粒中邻苯二甲酸酯(PAEs)的分布特征及人体健康暴露风险

Distribution of phthalic acid esters(PAEs) in paddy soil and grains of rice in the Pearl River Delta region and the health risk assessment

选择珠三角地区（东莞、惠州、广州、番禺）4个水稻种植区,采集土壤（30个）和水稻谷粒（37个）样品,通过超声提取进行样品前处理,利用气相色谱-质谱仪（GC-MS）分析9种邻苯二甲酸酯（PAEs）化合物的含量,研究PAEs的污染特征和人体健康暴露风险。结果表明,4个地区稻田土壤中PAEs总含量（∑PAEs）为3.25～8.05 mg·kg^-1（平均为5.25 mg·kg^-1）,水稻谷粒的∑PAEs为1.77～4.13 mg·kg^-1（平均为2.93 mg·kg^-1）,两者均以东莞的平均值最高,分别为（6.26±1.45）mg·kg^-1和（3.13±0.71）mg·kg^-1。土壤和水稻谷粒中PAEs均以邻苯二甲酸正二丁酯（DBP）、邻苯二甲酸双（2-乙基己基）酯（DEHP）和邻苯二甲酸二异丁酯（DIBP）为主,三者的累计含量占∑PAEs的85%以上。水稻谷粒对PAEs化合物的生物富集系数在0.37～1.27之间,部分DBP、DIBP、DEHP的大于1。大米和谷壳中∑PAEs分别为1.33～3.22 mg·kg^-1（平均为2.17 mg·kg^-1）和0.81～2.61 mg·kg^-1（平均为1.43 mg·kg^-1）。若人体食用这些大米,成人和儿童对DBP和DEHP的日均摄入量均小于10μg·kg^-1bw·d^-1,低于美国环保局推荐的日允许摄入量（DBP：100μg·kg^-1bw·d^-1,DEHP：20μg·kg^-1bw·d^-1）,健康暴露风险较小。但人体通过食用大米的长期低剂量暴露不容忽视。

This study aimed to investigate the distribution of PAEs in paddy soil and grains of rice（Oryza sativa L.）within the Pearl River Delta region and to evaluate the human health risk of PAEs via the ingestion of rice. Paddy soil samples（n=30）and grain samples（n=37）were collected from the rice cultivation areas of four cities（i.e., Dongguan, Guangzhou, Huizhou, Panyu） in this region. Nine PAE com-pounds in samples were ultrasonic-assisted extracted and analyzed using gas chromatography coupled with mass spectrometry（GC-MS）. The results show that the sum concentrations of nine PAE compounds（∑PAEs）in paddy soils ranged from 3.25 to 8.05 mg·kg^-1with a mean of5.25 mg·kg^-1, and those in grains were between 1.77 and 4.13 mg·kg^-1with a mean of 2.93 mg·kg^-1. The highest average concentrations in both of paddy soil（6.26±1.45 mg·kg^-1）and grains（3.13±0.71 mg·kg^-1）were observed in the samples from Dongguan City. Di-n-butyl phthalate（DBP）, di-（2-ethylhexyl）phthalate（DEHP）and di-iso-butyl phthalate（DIBP）were the most abundant compounds, accounting for more than 85% of the ∑PAEs. The bioaccumulation factor of grains to PAEs（defined as the ratio of PAE concentrations in grains to those in soil）varied from 0.37 to 1.27, and some of them for DBP, DEHP and DIBP were greater than 1.0. The ∑PAEs in rice and chaff ranged from1.33 to 3.22 mg·kg^-1（with a mean of 2.17 mg·kg^-1）and from 0.81 to 2.61 mg·kg^-1（with a mean of 1.43 mg·kg^-1）. Estimated daily intakes of DBP and DEHP for adult ranged from 0.52 to 2.61 μg·kg^-1bw·d^-1and from 0.65 to 4.09 μg·kg^-1bw·d^-1, those for child ranged 1.12 to5.58 μg·kg^-1bw·d^-1and from 1.57 to 9.91 μg·kg^-1bw·d^-1, respectively, via the ingestion of rice of this study, being lower than the reference doses proposed by U.S. Environmental Protection Agency（DBP： 100 μg·kg^-1bw·d^-1, DEHP： 20 μg·kg^-1bw·d^-1）. The human health risk via the ingestion of rice is relatively low.