DEHP Contamination Of Vegetables And The Influence Factors Corresponding Various Pollution Sources

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.