厌氧消化酸累积条件下强化产甲烷研究与应用

厌氧消化系统在实际运行中易受多种条件的影响,导致挥发性脂肪酸积累,挥发性脂肪酸的积累进一步抑制产甲烷作用,最终导致厌氧消化系统崩溃。分析了pH值、挥发性脂肪酸的种类和浓度是酸累积抑制产甲烷的原因,综述了利用投加嗜酸产甲烷菌和丙酸产甲烷菌的生物强化技术与投加磁铁矿、纳米零价铁、活性炭、生物炭、石墨烯的外源强化技术消除酸累积取得的效果,展望了未来研究方向可从加强酸累积对产甲烷抑制作用的机理探究,以及利用数学模型对酸累积的过程进行预警和调控等方面开展。

Citric Acid Accumulation in an Alkali_tolerant Plant Puccinellia tenuiflora Under Alkaline Stress

The accumulation of citric acid and associated correlative strain indexes were investigated in the seedlings of Puccinellia tenuiflora (Griseb.) Scribn. et Merr. stressed with 0-175 mmol/L Na 2CO 3. The results showed that the citric acid accumulation is a specific physiological respond of this plant to alkali_stress. On the contrary, the citric acid content decreased slightly in this plant stressed with 0-400 mmol/L neutral salt NaCl. The accumulation of citric acid increased with increasing strength of alkali_stress, the citric acid content increased gently when the strength was lower than 100 mmol/L Na 2CO 3, but increased obviously when the strength was higher than 100 mmol/L Na 2CO 3. The citric acid rapidly accumulated at early alkali_stress, an obvious raise can be mensurated after 4 h. About 48 h after treatment, the amount of citric acid accumulated nearly reached the maximum. In various parts of P. tenuiflora seedlings alkali_stressed for 144 h, the order of citric acid content from high to low is: old leaf, mature leaf, old leaf sheath, young leaf sheath, young stem, old stem, and young leaf. In the mature leaf, the citric acid content gradually increased with increasing strength of alkali_stress, while the citric acid content increased sharply in old leaf and sheath just for strength higher than 125 mmol/L. There was little change of citric acid content in stem, but no change in young leaf. The results of the experiment showed that citric acid was outstanding among accumulated organic acid caused by alkali_stress. The contribution of other organic acids was negligible.

Protective Effects of Glycinebetaine on Brassica chinensis Under Salt Stress

Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by the leaf of B. chinensis . Its application (0-20 mmol/L) enhanced the plant tolerance to salt stress. The treatment of 15 mmol/L GB significantly decreased the Na + accumulation in leaf and root under NaCl stress. This difference in accumulating Na + and K + is caused by higher selectivity of root absorption. Furthermore, GB increased H +_ATPase activity of root plasma membrane evidently. This result strongly suggested that in root the decreased Na + accumulation was caused by the GB accumulation that enhanced the extrusion of Na + from the cell in some way through plasma membrane transporter, e.g. Na +/H + antiport driven by H +_ATPase. The GB application was also found to stabilize the plasma membrane, to decrease the loss of chlorophyll, and to stimulate the osmosis induced proline response under salt stress.

Effects of Amino Acids Replacing Nitrate on Growth,Nitrate Accumulation,and Macroelement Concentrations in Pak-choi (Brassica chinensis L.)

A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N）, phosphorus （P）, and potassium （K） in pak-choi （Brassica chinensis L.） shoots. When 20% of nitrate-N was replaced with arginine （Arg） compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly （P ≤ 0.05）, but when 20% of nitrate-N was replaced with alanine （Ala）, valine （Val）, leucine （Leu）, isoleucine （Ile）, proline （Pro）, phenylalanine （Phe）, methionine （Met）, aspartic acid （Asp）, glutamic acid （Glu）, lysine （Lys）, glycine （Gly）, serine （Ser）, threonine （Thr）, cysteine （Cys）, and tyrosine （Tyr）, shoot fresh and dry weights decreased significantly （P ≤ 0.05）. After replacing 20% of nitrate-N with asparagine （Asn） and glutamine （Gin）, shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine （His）, and Arg, significantly reduced （P ≤0.05） nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased （P ≤ 0.05）. Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.

Nitrite Accumulation during the Denitrification Process in SBR for the Treatment of Pre-treated Landfill Leachate

The nitrite accumulation in the denitrification process is investigated with sequencing batch reactor （SBR） treating pre-treated landfill leachate in anoxic/anaerobic up-flow anaerobic sludge bed I（UASB）. Nitrite accumulates obviously at different initial nitrate concentrations （64.9,54.8,49.3 and 29.5 mg·L^-1 ） and low temperatures, and the two break points on the oxidation-reduction potential （ORP） profile indicate the completion of nitrate and nitrite reduction. Usually, the nitrate reduction rate is used as the sole parameter to characterize the denitrification rate, and nitrite is not even measured. For accuracy, the total oxidized nitrogen （nitrate ＋ nitrite） is used as a measure, though details characterizing the process may be overlooked. Additionally, batch tests are conducted to investigate the effects of C/N ratios and types of carbon sources on the nitrite accumulation during the denitrification. It is observed that carbon source is sufficient for the reduction of nitrate to nitrite, but for further reduction of nitrite to nitrogen gas, is deficient when C/N is below the theoretical critical level of 3.75 based on the stoichiometry of denitrification. Five carbon sources used in this work, except for glucose, may cause the nitrite accumulation. From experimental results and cited literature, it is concluded that Alcaligene species may be contained in the SBR activated-sludge system.

Effect of Sludge Retention Time on Nitrite Accumulation in Real-time Control Biological Nitrogen Removal Sequencing Batch Reactor

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.

合成革废水中试实验短程硝化快速启动研究

采用有效容积为1 m^3的SBR反应器,以某合成革污水厂厌氧滤池出水为实验进水,控制温度约为34℃、pH值7.4~8.3、溶解氧质量浓度0.2~0.6 mg·L^(-1)、游离氨质量浓度约10~30 mg·L^(-1)、泥龄约25 d、并添加一定质量的Na Cl;在其它条件不变,控制运行温度为27℃并逐渐下降至23℃的条件下,分别用时12和24 d,实现了短程硝化工艺的成功启动.亚硝酸盐累积率均达97%以上,NH+4-N的N容积负荷去除率分别达到0.18、0.08 kg·(m^3·d)^(-1).该工艺运行效果良好,抗冲击能力较强.

Cloning and nucleotide sequence of D-hydantoinase gene of marine polyphosphate-accumulating bacterium, Halomonas sp. YSR-3

Hydantoinase is involved in the production of optically pure amino acids from racemic 5-mono-substituted hydantoins. We measured the D-hydantoinase activity in marine Halomonas sp. YSR-3 and amplified the D-hydantoinase gene by PCR. The gene was inserted into vector pGM-T and transformed into E. coli TOP10. The positive transformants with the D-hydantoinase gene were sequenced. The sequenced fragment comprises 1 510 base pairs. The D-hydantoinase gene from YSR-3 is 77% similar to that from Pseudomonas entornophila L4 by searching against the NCBI databse. The protein product of the YSR-3 D-hydantoinase gene is 75%, 73%, and 70% similar to those from Pseudomonasfluorescens Pf-5, Marinornonas sp. MED121, and Burkholderia vietnamiensis G4, respectively. The difference of the D-hydantoinase gene between marine Halornonas sp. YSR-3 and other terrestrial organisms is distinct.

Effect of Salinity Stress on Capsicum annuum Callus Growth, Regeneration and Callus Content of Capsaicin, Phenylalanine, Proline and Ascorbic Acid

The present research was conducted to study salinity effect on callus growth and regeneration from the local Chilli pepper cultivar as well as calli content of capsaicin, phenylalanine, proline and ascorbic acid. The results showed that the Pericarp gave the highest fresh and dry weight of 511.6 mg and 56.95 mg respectively at 9 dSm-1 compared with other interactions. Moreover the lowest fresh and dry weight was recorded for the root calli grown at 12 dSm-1. The highest regeneration percentage was 87.20% at 3 dSm-1 and the lowest was 6.70% at 9 dSm-1. For explant effect on regeneration, the highest percentage was 71.1% for shoot tips and the lowest was 23.30 % from the pericarp. However no plants were regenerated at 12 dSm-1 from all explants and at 9 dSm-1 from calli induced from roots, placenta and pericarps. Calli induced from Pericarp contain significantly higher Proline amount at 12 dSm-1 which was 34.65 μg/g and the lowest was 2.57 μg/g at 3 dSml. Moreover Phenylalanine ranged from 28.23 μg/g at 3 dSml and 41.50μg/g at 12 dSm1. While a wide range between the explants in the Ascorbic acid amount was recorded. The highest was 47.21 μg/g from the Placenta calli and the lowest was 0.98 μg/g from the Shoot tip calli. On the other hand calli produced from Placenta gave the highest amount of Capsaicin 53.11 μg/g at 9 dSm-1 which was not significantly different than the placenta and the pericarp at 12 dSml and the shoot tips, placenta and the pericarp at 9 μg/g. In conclusion Chili pepper callus tolerated salinity via the accumulation of Ascorbic acid, Proline, Phenylalanine and Capsaicin. Moreover Chili Pepper grown In vitro under salt stress contained high amount of Capsaicin the important pharmaceutical compound. Finally pepper plants were regenerated from salt stressed calli might be salt tolerant under field conditions.

Salt Stress Effects on Germination, Plant Growth and Accumulation of Metabolites in Five Leguminous Plants

The investigation was conducted to determine physiological criteria of early selection for salt tolerant leguminous plants. Plants were subjected to 5 levels of salt stress at the roots （0, 50, 100,150 and 200 mM NaCI）. Results showed that sodium chloride had an underrating effect on growth of stems and seed germination of the species studied. The germination rates of seeds of Glycine max and Phaseolus vulgaris （sensitive glyeophytes） were affected from 3 g/L of NaCl, with critical thresholds at 9 and 12 g/L respectively. In contrast, critical thresholds with Mucunapoggei （facultative halophyte）, Vigna unguiculata （moderately tolerant glycophyte） and P. adenanthus （natural halophyte） was found to be above 21 g/L. The reduction of stems growth rate were not significant in P. adenanthus whereas in M. poggei and V. unguiculata this inhibition was observed just when nutritive solutions were enriched with 200 mM. The lipid contents were reduced in all the species under salt stress, whereas proteins and proline contents in the leaves were substantially increased in tolerant species （M. poggei, P. adenanthus and V. unguiculata）. In contrast, proteins and leaf proline contents were negatively affected by salt concentration to G. max and P. vulgaris. Seed germination, proteins and proline could be used as physiological criteria of early selection for salt tolerant leguminous plants.

Storage and Subsequent Reactivation of Phosphate-Accumulating Aerobic Granules

Phosphate-accumulating aerobic granules cultivated in a sequencing batch reactor were composed of inner rod-shaped bacteria aggregates and outer twining filamentous bacteria. The influence of two-month storage under dif- ferent conditions on the storage and subsequent reactivation performance of aerobic granules was investigated. After two-month storage the granules sealed at 4 ~C in distilled water or normal saline （named granules A and granules B, respectively） could maintain their characteristics as before, while the granules idled in the reactor at room temperature （named granules C） exhibited decreased properties. During reactivation, granules A and granules B presented almost identical recovery performance, faster than granules C, in terms of phosphorus removal efficiency, mixed liquor sus- pended solids （MLSS）, phosphate release and accumulating ability. The results suggest that hermetical storage at low temperature promoted the maintenance of the granular properties and the reviving behaviors of phosphateaccumulating aerobic granules, and storage medium had little influence on the storage and recovery perfomlance.

Cloning and Characterization of a Lycium chinense Carotenoid Isomerase Gene Enhancing Carotenoid Accumulation in Transgenic Tobacco

Carotenoid isomerase （CRTISO）is a key enzyme that catalyzes the conversion of cis-lycopene to all- trans tycopene. In this study, we isolated and characterized the CRTISO gene from Lycium chinense （LcCRTISO） for the first time. The open reading flame of LcCRTISO was 1 815 bp encoding a protein of 604 amino acids with a molecular mass of 66.24 kDa. Amino acid sequence analysis revealed that the LcCRTISO had a high level of simi- larity to other CRTISO. Phylogenetic analysis displayed that LcCRTISO kept a closer relationship with the CRTISO of plants than with those of other species. Semi-quantitative PCR analysis indicated that LcCRTISO gene was expressed in all tissues tested with the highest expression in maturing fruits. The overexpression of LcCRTISO gene in transgenic tobacco resulted in an increase of total carotenoids in the leaves with [3-carotene and lutein being the predominants. The results obtained here clearly suggested that the LcCRTISO gene was a promising candidate for carotenoid production.

Variation in Rubisco and other photosynthetic parameters in the life cycle of Haematococcus pluvialis

Cells of Haematococcus pluvialis Flot. et Will were collected in four different growth phases. We quantified the initial and total enzyme activity of ribulose-1,5-bisphosphate carboxylase （Rubiseo） in crude extracts, and the relative expression of large-subunit ribulose-1,5-bisphosphate caboxylase / oxygenase （rbcL） mRNA. We measured the ratio of photosynthetic rate to respiration rate （P/R）, maximal effective quantum yield of photosystem II （Fv/Fm）, electron transport rate （ETR）, actual photochemical efficiency of PSI1 in the light （ФPSII）, and non-photochemical quenching （NPQ）. Green vegetative cells were found to be in the most active state, with a relatively higher P/R ratio. These cells also displayed the lowest NPQ and the highest Fv/Fm, ETR, and ФPSII, indicating the most effective PSII. However, both Rubisco activity and rbcL mRNA expression were the lowest measured. In orange resting cysts with relatively lower P/R and NPQ, Rubisco activity and rbcL expression reached a peak, while Fv/Fm, ETR, and ФPSII were the lowest measured. Taking into account the methods of astaxanthin induction used in industry, we suggest that Rubisco may participate in astaxanthin accumulation in H. pluvialis. A continuous and sufficient supply of a carbon source such as CO2 may therefore aid the large scale production of astaxanthin.

Role of Carbon Substrates Added in the Transformation of Surplus Nitrate to Organic Nitrogen in a Calcareous Soil

Excessive amounts of nitrate have accumulated in many soils on the North China Plain due to the large amounts of chemical N fertilizers or manures used in combination with low carbon inputs. We investigated the potential of different carbon substrates added to transform soil nitrate into soil organic N （SON）. A 56-d laboratory incubation experiment using the 15N tracer （K15NO3） technique was carried out to elucidate the proportion of SON derived from accumulated soil nitrate following amendment with glucose or maize straw at controlled soil temperature and moisture. The dynamics and isotopic abundance of mineral N （NO3 and NH4＋） and SON and greenhouse gas （N20 and CO2） emissions during the incubation were investigated. Although carbon amendments markedly stimulated transformation of nitrate to newly formed SON, this was only a substitution effect of the newly formed SON with native SON because SON at the end of the incubation period was not significantly different （P 〉 0.05） from that in control soil without added C. At the end of the incubation period, amendment with glucose, a readily available C source, increased nitrate immobilization by 2.65 times and total N20-N emission by 33.7 times, as compared with maize straw amendment. Moreover, the differences in SON and total N20-N emission between the treatments with glucose and maize straw were significant （P 〈 0.05）. However, the total N20-N emission in the straw treatment was not significantly （P ~ 0.05） greater than that in the control. Straw amendment may be a potential option in agricultural practice for transformation of nitrate N to SON and minimization of N20 emitted as well as restriction of NO3-N leaching.

Formation and accumulation of oil and gas in marine carbonate sequences in Chinese sedimentary basins

Advances in studies of formation and accumulation mechanisms of oil and gas in marine carbonate sequences have led to continuing breakthroughs of petroleum exploration in marine carbonate sequences in Chinese sedimentary basins in recent years. The recently discovered giant Tahe Oil Field and Puguang Gas Field have provided geological entities for further studies of the formation and accumulation of oil and gas in marine carbonate sequences. Marine carbonate sequences in China are characterized by old age, multiple structural deformation, differential thermal evolution of source rocks, various reservoir types (i.e. reef-bank complex and paleo-weathered crust karst reservoir), uneven development of caprocks, especially gypsum seal, and multi-episodes of hydrocarbon accumulation and readjustment. As a result, the formation of hydrocarbon accumulations in the Chinese marine carbonate sequences has the following features: (i) the high-quality marine source rocks of shale and calcareous mudstone are often associated with siliceous rocks or calcareous rocks and were deposited in slope environments. They are rich in organic matter, have a higher hydrocarbon generation potential, but experienced variable thermal evolutions in different basins or different areas of the same basin. (ii) High quality reservoirs are controlled by both primary depositional environments and later modifications including diagenetic modifications, structural deformations, and fluid effects. (iii) Development of high-quality caprocks, especially gypsum seals, is the key to the formation of large-and medium-sized oil and gas fields in marine carbonate sequences. Gypsum often constitutes the caprock for most of large sized gas fields. Given that Chinese marine carbonate sequences are of old age and subject to multiple episodes of structural deformation and superposition, oil and gas tend to accumulate in the slopes and structural hinge zones, since the slopes favor the development of effective assemblage of source-reservoir-caprock, high quality source rocks, good reservoirs such as reef-bank complex, and various caprocks. As the structural hinge zones lay in the focus area of petroleum migration and experienced little structural deformation, they are also favorable places for hydrocarbon accumulation and preservation.

Changes in the physiological properties and kinetics of citric acid accumulation via carbon ion irradiation mutagenesis of Aspergillus niger

The objective of this work was to produce citric acid from corn starch using a newly isolated mutant of Aspergillus niger, and to analyze the relationship between changes in the physiological properties of A. niger induced by carbon ion irradiation and citric acid accumulation. Our results showed that the physiological characteristics of conidia in A. niger were closely related to citric acid accumulation and that lower growth rate and viability of conidia may be beneficial to citric acid accumulation. Using corn starch as a raw material, a high-yielding citric acid mutant, named HW2, was obtained. In a 10-L bioreactor, HW2 can accumulate 118.9 g/L citdc acid with a residual total sugar concentration of only 14.4 g/L. This represented an 18% increase in citric acid accumulation and a 12.5% decrease in sugar utilization compared with the original strain.

Lignite-Derived Humic Acid Effect on Growth of Wheat Plants in Different Soils

Humic acid （HA）, a fairly stable product of decomposed organic matter that consequently accumulates in ecological systems, enhances plant growth by chelating unavailable nutrients and buffering pH. We examined the effect of HA derived from lignite on growth and macronutrient uptake of wheat （Triticum acstivum L.） grown in earthen pots under greenhouse conditions. The soils used in the pot experiment were a calcareous Haplustalf and a non-calcareous Haplustalf collected from Raisalpur and Guliana, respectively, in Punjab Province, Pakistan. The experiment consisted of four treatments with HA levels of 0 （control without HA）, 30, 60, and 90 mg kg^-1 soil designated as HA0, HA1, HA2, and HA3, respectively. In the treatment without HA （HA0）, nitrogen （N）, phosphorus （P）, and potassium （K） were applied at 200, 100, and 125 mg kg^-1 soil, respectively. Significant differences among HA levels were recorded for wheat growth （plant height and shoot weight） and N uptake. On an average of both soils, the largest increases in plant height and shoot fresh and dry weights were found with HA2 （60 mg kg^-1 soil）, being 10%, 25%, and 18%, respectively, as compared to the control without HA （HA0）. Both soils responded positively towards HA application. The wheat growth and N uptake in the non-calcareous soil were higher than those of the calcareous soil. The HA application significantly improved K concentration of the non-calcareous soil and P and NO3-N of the calcareous soil. The highest rate of HA （90 mg kg^-1 soil） had a negative effect on growth and nutrient uptake of wheat as well as nutrient accumulation in soil, whereas the medium dose of HA （60 mg kg^-1 soil） was more efficient in promoting wheat growth.

Jianpijiedu Fang improves survival of hepatocarcinoma mice by affecting phosphatase and tensin homolog, phosphoinositide 3-kinase, and focal adhesion kinase

OBJECTIVE: To investigate the effect of Jianpijiedu Fang (JPJDF) on phosphatase and tensin homolog (PTEN), phosphoinositide 3-kinase (PI3K), and focal adhesion kinase (FAK), and on the survival of hepatocellular carcinoma (HCC) nude mice. METHODS: Forty male nude mice were randomly divided into 4 groups. Human HCC tissue was implanted in the livers of three groups. After 24 h, the three groups were treated respectively with JPJDF (37.5 g/kg), saline (20 mL/kg) and Tegafur (FT-207, 160 mg/kg) once a day for 10 weeks. The control group without implanting the tissue was concurrently treated with saline (20 mL/kg). The survival data and body weight of all mice were recorded, and expression levels of PTEN, PI3K and FAK in normal tissue and cancer tissue of the livers were eval-uated with immunohistochemical method. RESULTS: The cumulative survival rate of the mice in the JPJDF group was higher than those of the other groups. The rate of weight loss was the lowest in JPJDF group. The survivability and weight loss rate in FT-207 group were the poorest in all groups. The expression intensity of PTEN was higher in normal tissues than in cancer tissues, and lower in the normal tissues of HCC models than in that of mice without HCC. The PTEN expression intensity in normal tissue and cancer tissue from mice treated with FT-207 were lower than that from the mice treated with JPJDF or saline.The expression intensity of PI3K was higher in cancer tissue than in normal tissue. The PI3K expression intensity was the lowest in normal tissue and cancer tissue from mice treated with JPJDF, and the intensity from mice treated with FT-207 was the highest. In mice treated with JPJDF, the expression intensity of FAK was higher in the normal tissue and lower in the cancer tissue than those of the other treatment groups. CONCLUSION: The mechanism accounting for the prolonged survival of HCC-bearing mice treated with JPJDF might be related to the reduction in weight loss and the benign regulation of PTEN, PI3K, and FAK.

Contamination of Phthalate Esters in Vegetable Agriculture and Human Cumulative Risk Assessment

Phthalate esters （PAEs）, which can disturb human endocrine system, have been widely detected in vegetable greenhouse agriculture in China. To investigate the effects of environmental factors on PAEs in soils, pollution sources were identified, and the cumulative risks of PAEs to humans through vegetables in the diet were evaluated in this study. Ninety-eight vegetable samples were collected from 10 markets along with 128 vegetable and 111 soil samples from agricultural greenhouses and open field. All soil and vegetable samples were contaminated with PAEs, and the total concentrations of the 5 PAEs, including dimethyl phthalate （DMP）, diethyl phthalate （DEP）, di-iso-butyl phthalate （DiBP）, di-n-butyl phthalate （DnBP）, and di-2-ethylhexyl phthalate （DEHP）, were in the ranges of 0.26-2.53 mg kg-1 for soils and 0.95-8.09 mg kg-1 for vegetables. Three components extracted from principle component analysis could explain 51.2%, 19.8%, and 15.3% of the total variance of the 5 PAEs in soils, which may represent three major sources of PAEs, i.e., wastewater irrigation, application of fertilizers and pesticides, and plastic film. Long-term greenhouse cultivation could accumulate DEHP in soils, and a higher soil FeOx content reduced the DnBP concentration. Based on a survey of vegetables in the diet, the hazard index of PAEs was 〈 0.15 for individuals in different cities. The exposure of PAEs through vegetable intake was higher than the total exposure from other food stuffS, inhalation, and dermal absorption. More attention should be g!ven to controlling PAEs in greenhouse vegetables.