Studies On Phthalate Easters Pollution In Protected Fields

In order to illustrate the phthalate easters pollution of air-soil-vegetable system in vegetable production fields, protected fields in Shouguang city were investigated, and DMP, DEP, DBP, DEHP were determinated by HPLC, GC. The changes of PAEs content in soil and air of greenhouse were studied. Pot experiment was conducted to discuss the transformation of PAEs in cucumber, tomato and carrot. And the elimination of PAEs in vegetables was probed to. The main results and conclusions were as follows:1 Conditions of HPLC and GC were probed to, and their correlation coefficients and limits of detection met the requirement of microanalysis. The range of detection limits of HPLC was from 0.702 ng to 1.920 ng, and correlation coefficients was more than 0.998. And to GC, The range of detection limits was from 0.15 mg/L to 0.24 mg/L, and correlation coefficients were more than 0.997.2 The investigation in Shouguang city showed: (1) The total content of DMP, DEP, DBP and DEHP was from 7.35 mg/kg to 33.39mg/kg. And there was no difference among five vegetable production fields. (2) The DBP content in vegetables was the highest and more than 50 percent of total PAEs content. The contents of DEP and DMP were the lowest, even were lower than detection limit. (3) The PAEs content in soil of different planting years, cucumber and tomato was in the order of DBP>DEHP>DEP>DMP, and did not increase with the planting years.3 Lunar variation of PAEs content in soil showed that, the DBP, DEHP, DMP or DEP content was higher than detection limit in 0～5cm layer soil during the first month after the greenhouse was covered with plastic film, and the PAEs content in soil was in the order of DBP>DEHP>DEP>DMP. The DBP, DEHP and DMP content increased with the time, but DEP content was steady.4 Annual variation of PAEs content in soil showed that there were no differences among the variation of different layer soil. The trend of annual variation was increased- steady- increased- decreased. PAEs content among different layer soil was in the order of 0～5cm layer>5～10cm layer>10～20cm layer>20～40cm layer. And the content of different kinds of PAEs in the same layer soil was in the order of DBP>DEHP>DMP>DEP. 5 Daily variation of PAEs content in air showed that DBP content was the highest, secondly was DEHP, and the content of DMP and DEP was lower than detection limit. The curve of daily variation was parabola, and the peak appeared at 1 p.m.. 6 Lunar variation of PAEs content in air showed that only the content of DBP and DEHP was higher than detection limit after the greenhouse was covered with plastic film, and three stages were found in the luner variation: the release rate increased at the 1st to 5th day, the release rate lowed down at the 5th to 20th day, and the release rate was steady at the 20th to 30th day.7 Annual variation of PAEs content in air showed that only the content of DBP and DEHP was higher than detection limit. The content of DBP and DEHP increased continually from October, 2005 to February, 2006, and then kept steady from February to March. From April to June, the content rapidly decreased because of aeration in the greenhouse.8 The pot experiment of PAEs appended showed that the DBP content in root and leaves of carrot was in the order of high treament>low treament>CK. And the DEHP content in root and leaves of carrot was the highest, there was no difference between low treatment and CK. The DBP content in root of carrot was higher than in leaves, and the DEHP content in leaves was higher than in root. In fruit, root, leaves of cucumber and in fruit, stem, leaves of tomato, the content of DBP and DEHP was in the order of high treament>low treament>CK. There was no difference in the DBP and DEHP contents in stem of cucumber and tomato between high treatment and low treatment. The DBP content in cucumber and tomato fruit was higher than DEHP, and in root the content was reverse, but there was no difference between DBP and DEHP in the stem and leaves.9 The washing experiments showed that after washed by water or surfactant, the content of PAEs in vegetables was reduced remarkably. The eliminated ratio of DBP and DEHP in vegetables was about 50 percent after the vegetables were washed by water, and the eliminated ratio was about 80 percent after washed by surfactant. And eliminated ratio of DBP was higher than DEHP.