【作者】 傅小伟；

【导师】 杜琪珍；

【作者基本信息】 浙江工商大学 ， 食品科学， 2012， 博士

【摘要】 随着工业生产和塑料制品的使用,塑料垃圾的大量增加,邻苯二甲酸酯(PAEs)不断进入环境,已成为全球性的最普遍的污染物。邻苯二甲酸酯(2-乙基己基)酯(DEHP)是塑化剂的主要成分,它可以从塑料中释放至大气、土壤和水域中,迁移到蔬菜、水果和庄稼,通过食物链进入人体,从而对人类健康造成危害。本研究开展了主要蔬菜受DEHP污染状况的调查和污染原因分析,蔬菜吸收累积DEHP受污染源的影响及其规律,并探讨了不同种类蔬菜吸收DEHP能力的差异。主要结论如下：(1)对不同采样点的蔬菜进行了DEHP含量分析,采于塑料厂周边农田的叶菜类蔬菜可食部分和瓜果类叶子部分均被检出DEHP,且受DEHP污染较为严重；采自农贸市场和路边小摊的叶菜类和瓜果类亦有部分检出DEHP;而采于山区的蔬菜DEHP污染极少。冬令时节采集的蔬菜样品中的DEHP含量比夏令时节相同蔬菜样品DEHP含量高。塑料厂周边瓜果类蔬菜的可食部分也均有DEHP检出,但较其叶子部分中的DEHP含量低。(2)根据蔬菜的污染状况,分析采样点的土壤、大气和蔬菜中的DEHP含量,结果表明,蔬菜叶中累积DEHP的量与大气中DEHP含量有较好的线性关系；而其与土壤中DEHP含量的线性关系不明显。(3)分析了地膜导致的蔬菜累积DEHP的情况。结果显示,种植在用地膜覆盖的土地上的蔬菜均能检出DEHP。同厚度条件下,黑地膜种植的蔬菜中(除了小葱)含有的DEHP高于白地膜的。地膜厚度越大,膜中释放出的DEHP越多,蔬菜累积DEHP的量亦高。除小葱外,蔬菜中DEHP含量与地膜厚度的呈线性相关(R2>0.8)。(4)通过盆栽试验,发现不同种类蔬菜吸收DEHP的能力有较大差异,冬瓜、南瓜、黄瓜及大白菜的叶子累积较高DEHP。蔬菜不同部位中DEHP的含量顺序为叶子>茎>根。田间地膜试验中发现雪里蕻、生菜、南瓜、丝瓜和黄瓜含量较高。(5)以大棚塑料膜为DEHP污染源,研究了DEHP在棚膜/棚内空气/棚内蔬菜的转移规律。结果显示,棚内空气中DEHP的日含量变化曲线呈峰形,与棚内温度的日变化情况基本一致。棚内青菜样品中DEHP的日含量变化呈缓慢增加趋势,与空气中DEHP含量变化趋势稍有差异。蔬菜大棚影响棚内蔬菜吸收累积DEHP,这些因素分别是塑料膜材质和厚度,大棚高度和棚龄。塑料膜中所含DEHP量越高,棚内蔬菜中DEHP含量越高；塑料膜越厚,所搭建的大棚高度越低,棚龄越短,蔬菜累积的DEHP量越高。(6)通过在塑料厂周边农田种植蔬菜,研究了蔬菜中DEHP累积量。结果得出,试验田距塑料厂越近,气温越高,位于污染源的下风向,其大气中DEHP的含量越高,蔬菜中DEHP含量也越高。另外,试验田上方空气中DEHP的浓度水平与蔬菜累积DEHP的量呈正相关,相关系数均大于0.95,佐证了蔬菜受DEHP污染主要来自大气中的DEHP。以上研究结果可为避免蔬菜DEHP污染、种植出符合食品安全标准的蔬菜提供科学依据。更多还原

【Abstract】 Phthalates have being caused severe environmental and food contaminants since the use of plasterers in plastic products. Di-(2-ethylhexyl) phthalate (DEHP), the main substance in plasticizers, can be continuously released from the plastic to the atmosphere, soil and water, and then migrate to vegetables, fruits and crops, which lead to uptake of human body through food chain. Because DEHP possesses teratogenicity and carcinogenicity, the DEHP-contamination degree of vegetables, the source of the contamination, and the factors influencing the accumulation of DEHP in vegetables from different pollution sources were investigated in the present paper. The main results are summarized as follows:(1) DEHP contents of vegetables from the different sampling sites were analyzed. The edible parts of leafy and fruit vegetables had DEHP accumulation from the farmland surrounding the plastics factory, and some of them were seriously contaminated. DEHP was also detected in part of leafy and fruit vegetables from the markets and roadside stalls. However, DEHP of vegetables from the mountains were rarely detected. The DEHP content of the vegetables in winter were higher than those in summer. The edible parts of fruits surrounding the plastic factory were also polluted by DEHP, but the DEHP contents in fruits were lower than that of in corresponding leaves.(2) The DEHP contents in soil, atmosphere and the selected vegetables were determined. The regression analyses of the data showed that there was in good linear relationship between the content of DEHP in the leaves of vegetables and in the atmosphere while no linear relationship between the content DEHP in vegetable and in soil, which suggested that DEHP in vegetables came from air, not soil.(3) DEHP contents in the vegetables cultivated in soil covered by mulch film were analyed. The results showed that all the vegetables was polluted by DEHP, and black film could cause more severe DEHP contamination than white film, which imply black film possesses stronger release ability of DEHP than white film. In addition, the greater the thickness of mulch film, the higher the DEHP amount released from the film to air, and caused more DEHP accumulation in the vegetables. The linear coefficients R2 between the film thickness and DEHP contents of the vegetables were more than 0.8, except for the onion samples.(4) Pot-planting experiment with mulch film was conducted for a comparision of ability of DEHP uptake of different vegetable plants. The result showed the leaves of B. hispida, C. moschata, C. sativus and B. parachinensis possessed strong ability of DEHP uptake. Usually, leaves accumulated the highest DEHP content, followed by stem and root. The DEHP contents of vegetables planting in field with mulch film were determined. The result showed that there were high DEHP levels in B. juncea, L. sativa, C. moschata, L. cylindrical and C. sativus.(5) The migration of DEHP from the cover film of greenhouse to atmosphere and vegetables was studied. The results exhibited that the daily DEHP content in air increased with the increase of the greenhouse temperature and the change curve of DEHP exhibited in peak shape. In the greenhouse, the daily DEHP content of vegetable was increased from morning to night, and the monthly DEHP content changes in vegetable were consistent with the change of DEHP levels in the greenhouse air. The factors influencing the DEHP uptake of vegetables in greenhouse included the material and thickness of the plastic membrane, the height and the age of the greenhouse. A low and young greenhouse covered with a thick film caused a higher DEHP content of vegetable than a high and old one covered with a thin film.(6) The accumulation of DEHP in vegetables cultivating around a plastic factory was studied. The result showed that high DEHP content was detected in the vegetables cultivated the site near to the plastic factory, and temperature and wind direction were the key factors influencing the measurable DEHP concentration of the air and vegetables. A strong positive linear correlation between atmospheric DEHP concentration and DEHP content of the vegetable crops was found, and all the correlation coefficients (R2) were more than 0.95, which indirectly demonstrated that the DEHP in plants is distributed by the uptake of leaves, stem and fruits from atmosphere.The total results of the present paper can provide scientific knowledge for avoiding DEHP contamination of vegetables to meet the requirement of food safety.更多还原