Distribution of phthalate esters in urban soils of subtropical city, Guangzhou, China

Surface soils from 37 sampling sites including roadsides (RS), parks (PA) and residential areas (RE) of the Subtropical City, Guangzhou, were collected in December of 2005 and analyzed for 16 phthalate esters (PAEs). PAEs were detected in all surface soils analyzed, which indicate that PAEs are ubiquitous environmental contaminants. The summation operator(16)PAEs concentrations ranged from 1.67 to 322 microg g(-1)-dry weight (dw), with the median concentration of 17.7 microg g(-1)-dw, mainly originating from municipal solid waste leachate, discarded plastic effusion, municipal sewage and atmospheric depositions. Concentrations of PAEs were poorly correlated with soil organic carbon content, suggesting mixing process between local and on-going sources. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs, with the median concentrations of 1.63 microg g(-1)-dw, 1.80 microg g(-1)-dw and 14.8 microg g(-1)-dw, respectively, and accounted for 74.2-99.8% of the summation operator(16)PAEs concentrations. Principal Component Analysis (PCA) was applied to the distribution patterns of PAEs in the urban soils. Significant correlations existed among DiBP, DnBP, and DEHP, and between dimethyl phthalate (DMP) and diethyl phthalate (DEP). No significant differences of PAE congeneric profiles were observed between this and studies conducted elsewhere, which is consistent with the application of similar commercial PAEs around the world. As compared to the results from other studies, the urban soils of Guangzhou city were severely contaminated with PAEs. The environmental and human health risks posed by PAEs in the urban soils of Guangzhou city may deserve further attention.     

Identifying the potential sources of di-(2-ethylhexyl) phthalate contamination in the sediment of the Houjing River in southern Taiwan

Sediment samples were analyzed for di-(2-ethylhexyl) phthalate (DEHP), an organic endocrine disruptor, in Houjing River in southern Taiwan. The average DEHP concentration at 10 sampling locations, spanning from upper, middle, and lower segments of the stream, was calculated at 3.81+/-6.36mgkg(-1)drywt. Highest concentration was recorded at the Jhongsing Bridge (20.22mgkg(-1)drywt.) near the Dashe Industrial Park, followed by the Renwu Bridge (8.93mgkg(-1)drywt.) near the Renwu Industrial Park. The surface sediment concentration of DEHP was found to be higher in the dry season (October and December), and lower in the wet (flood) season (August), indicating that sources of DEHP remained active and continued to recharge the Houjing River. Vertical sediment core analysis revealed that highest concentration occurred at the depth of 40-60cm, indicating that historical discharges of DEPH may have been higher than recent years. Domestic comparison of DEHP concentrations in sediment from highest to lowest could be categorized as northern, southern, central, and eastern Taiwan, respectively, and seemed to be positively correlated with population density and/or industrial activity. Compared to other countries, DEHP concentration of the Houjing River was relatively higher than rivers studied in Japan, Germany, Italy, and Malaysia, and was relatively lower than the Aire and Trent Rivers in the United Kingdom.     

GC-MS法同时测定橡皮擦中22种邻苯二甲酸酯增塑剂

建立了气相色谱-质谱(GC-MS)分段选择离子监测(SIM)模式分析同时测定橡皮擦中22种邻苯二甲酸酯(PAEs)增塑剂含量的方法。该方法具有良好线性,相关系数R均大于0.999,检测限在1.3 mg/kg～128.9 mg/kg之间,平均回收率在70.2%～105.6%,相对标准偏差在2.57%～9.88%之间。通过该方法对国内橡皮擦中PAEs增塑剂进行检测,实际样品均检出邻苯二甲酸二(2-乙基)己酯(DEHP),含量最高达32.5%。     

Subcritical water extraction for the remediation of phthalate ester-contaminated soil

Subcritical water has been used as an environment-friendly extraction fluid for many classes of organic compounds. It was used for the removal of phthalate esters (PEs), such as di-methyl phthalate, DMP; di-ethyl phthalate, DEP; di-iso-propyl phthalate, DIPP; di-n-butyl phthalate, DBP; benzyl butyl phthalate, BBP; di-n-pentyl phthalate, DpentP; di-n-hexyl phthalate, DHXP; di-heptyl phthalate, DheptP; di-2-ethylhexyl phthalate, DEHP; di-n-nonyl phthalate, DNP; di-n-octyl phthalate, DOP; di-n-decyl phthalate, DDP, in soil samples under the optimum condition of 250 °C and 10 MPa in our study. The soil samples cleaned with subcritical water were extracted by homemade accelerated solvent extraction system (ASE) and analyzed by HPLC-UV to check for soil remediation efficiency. Three types of soil collected at different sites in Taiwan have been tested. Although at higher PEs concentration levels, the modification of treatments may be necessary for satisfactory removal of the contaminants, soil samples of different PEs levels treated with subcritical water extraction (SCWE) were analyzed and the results indicated removal efficiency ranges of 80-90% for PEs spiked in soil samples. Soil samples contaminated with native DEHP were treated and gave comparable recovery efficiencies. Our results indicate that the applications of subcritical water as soil remediation for removal of PEs contaminant are feasible.     

Alkylphenols and phthalates in bottled waters

The aim of this study was to investigate the occurrence of endocrine disrupting compounds (EDCs) in bottled waters. The examined compounds were bisphenol A (BPA), nonylphenol (NP), tert-octylphenol (tOP), dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), di(2-ethylhexyl)phthalate (DEHP) and di(n-octyl)phthalate (DNOP). The presence of EDCs in bottled waters under poor storage conditions was also investigated after exposure outdoors under realistic conditions for 15 and 30 days. EDCs were recovered after liquid-liquid extraction and determined by employing Gas Chromatography-Mass Spectrometry. Most of these compounds were detected in bottled water from different brands purchased from local market. Storage at outdoor conditions had no significant effect on the concentrations of the examined compounds. Only BPA occurred at higher concentrations in polycarbonate containers exhibited an increasing trend during exposure. The estimated exposure to EDCs via consumption of drinking water was very low.     

Distribution, partitioning and sources of polycyclic aromatic hydrocarbons in Daliao River water system in dry season, China

Eighteen polycyclic aromatic hydrocarbons (PAHs) were analyzed in 29 surface water, 29 suspended particulate matter (SPM), 28 sediment, and 10 pore water samples from Daliao River water system in dry season. The total PAH concentration ranged from 570.2 to 2318.6 ng L(-1) in surface water, from 151.0 to 28483.8 ng L(-1) in SPM, from 102.9 to 3419.2 ng g(-1) in sediment and from 6.3 to 46.4 microg l(-1) in pore water. The concentration of dissolved PAHs was higher than that of particulate PAHs at many sites, but the opposite results were generally observed at the sites of wastewater discharge. The soluble level of PAHs was much higher in the pore water than in the water column. Generally, the water column of the polluted branch streams contained higher content of PAHs than their mainstream. The environmental behaviors and fates of PAHs were examined according to some physicochemical parameters such as pH, organic carbon, SPM content, water content and grain size in sediments. Results showed that organic carbon was the primary factor controlling the distribution of the PAHs in the Daliao River water system. Partitioning of PAHs between sediment solid phase and pore water phase was studied, and the relationship between logK(oc) and logK(ow) of PAHs on some sediments and the predicted values was compared. PAHs other than naphthalene and acenaphthylene would be accumulated largely in the sediment of the Dalaio River water system. The sources of PAHs were evaluated employing ratios of specific PAHs compounds and different wastewater discharge sources, indicating that combustion was the main source of PAHs input.     

Study on the interaction of phthalate esters to human serum albumin by steady-state and time-resolved fluorescence and circular dichroism spectroscopy

Phthalate esters (PAEs) are globally pervasive contaminants that are considered to be endocrine disruptor chemicals and toxic environmental priority pollutants. In this paper, the interactions between PAEs and human serum albumin (HSA) were examined by molecular modelling, steady state and time-resolved fluorescence, ultraviolet-visible spectroscopy (UV-vis) and circular dichroism spectroscopy (CD). The association constants between PAEs and HSA were determined using the Stern-Volmer and Scatchard equations. The binding of dimethyl phthalate (DMP) to HSA has a single class of binding site and its binding constants (K) are 4.08 × 10³, 3.97 × 10³, 3.45 × 10³, and 3.20 × 10³ L mol⁻¹ at 289, 296, 303, and 310 K, respectively. The Stern-Volmer and Scatchard plots both had two regression curves for HSA-butylbenzyl phthalate (BBP) and HSA-di-2-ethylhexyl phthalate (DEHP), which indicated that these bindings were via two types of binding sites: the numbers of binding site for the first type were lower than for the second type. The binding constants of the first type binding site were higher than those of the second type binding site at corresponding temperatures, the results suggesting that the first type of binding site had high affinity and the second binding site involved other sites with lower binding affinity and selectivity. The thermodynamic parameters of the binding reactions (ΔG°, ΔH° and ΔS°) were measured, and they indicated the presences of hydrophobic forces and hydrogen interactions in the PAEs-HSA interactions, which agreed well with the results from molecular modelling. The alterations of protein secondary structure in the presence of PAEs were confirmed by UV-vis and CD spectroscopy. The time-resolved fluorescence study showed that the lifetime of Trp residue of HSA decreased after the addition of PAEs, which implied that the Trp residue of HSA was the main binding site.     

超高效液相色谱法测定冬瓜中DEHP的含量

邻苯二甲酸二（2-乙基己基）酯（DEHP）是一种应用较广泛的邻苯二甲酸酯类有机污染物。对冬瓜中DEHP的含量测定方法进行了研究,建立了超高效液相色谱（UPLC）测定蔬菜中DEHP含量的方法。实验结果表明：方法线性范围为0．0001～1．0mg／mL,样品检出限为3．62×10-3mg／kg,加标回收率为91．3％～96．7％。该分析方法具有时间短、选择性好、干扰少等特点,能满足蔬菜中DEHP的分析要求,具有实际的检测价值。     

高效液相色谱测定啤酒瓶盖内衬垫DEHP的含量

建立了高效液相色谱测定啤酒瓶盖内衬垫中邻苯二甲酸二(2-乙基己基)酯(DEHP)含量的方法。通过改变样品的前处理方法及检测的色谱条件,以保留时间来定性,外标法来定量,对实验结果进行优化。实验得到:样品在经过无水乙醇浸泡处理,流动相甲醇与水的体积比为95∶5,紫外检测器检测波长为275 nm时,能获得的分离效果最佳;在该分析条件下,DEHP标准曲线呈现很好的线性关系,相关系数均大于0.998,精密度RSD<1.5%,DEHP在无水乙醇中浸泡的溶出量为24.45%,在95%甲醇中浸泡的溶出量为15.97%。     

纸包装油墨中增塑剂向食品模拟物Tenax的迁移

通过纸张表印油墨的实验室印制方法,模拟真实纸包装油墨中四种增塑剂向食品模拟物Tenax的迁移,使用气相色谱法检测不同温度(50℃、70℃和100℃)、纸张克重(240g/m2和400g/m2)和增塑剂初始含量下的迁移量。结果表明,纸包装油墨中增塑剂的迁移行为由其扩散系数和分配系数决定,温度和纸张克重对增塑剂迁移行为影响较大,实际中要避免增塑剂的迁移对人体造成的危害。     

Estrogenic activity of chemicals for dental and similar use in vitro

The estrogenic activities of chemicals for dental and similar use were tested by a reporter gene assay (yeast two-hybrid system) and an estrogen/estrogen receptor (ER-) competition binding assay (fluorescence polarization system). Among the 10 chemicals [bisphenol-A (BPA), bis-2-hydroxypropyl methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), dibutyl phthalate (DBP), n-butyl benzyl phthalate (BBP), n-butyl phthalyl n-butyl glycolate (BPBG), di-2-ethylhexyl phthalate (DEHP), and di-2-ethylhexyl adipate (DOA)], which were diluted with DMSO to concentrations ranging from 5 × 10^-7 to 5 × 10^-3M, and 17-estradiol (E2) as a positive control, BPA and BBP showed estrogenic activity in these two assays, while the remaining eight chemicals did not at the concentrations tested. Additional data, together with in vivo and epidemiological examinations, are required. Such investigations should also provide information on the validity of these methods for testing the estrogenic activity of chemicals.     

Occurrence and phase distribution of selected pharmaceuticals in the Yangtze Estuary and its coastal zone

The occurrence and geochemical behavior of nine pharmaceutical compounds were investigated along the Yangtze River Estuary and its coastal area, by sampling and analysis of pharmaceuticals in sediment, suspended particulate matter (SPM), colloidal and soluble phases. In addition, the impact of sewage input was examined by sampling from sewage treatment plants (STP) effluent and its upstream and downstream in the Yangtze River. Although at relatively low concentrations in SPM and sediments, several pharmaceuticals were found at elevated concentration in filtered water samples from STP-affected sites. STP is therefore an important input of pharmaceuticals in the study area. Colloidal phase was further separated from bulk water samples using cross-flow ultrafiltration (CFUF), confirming it being an effective sorbent for pharmaceuticals with high sorption capacity which are 2-4 orders of magnitude higher than SPM. Moreover, mass balance calculations showed that significant percentages of selected pharmaceutical compounds were associated with aquatic colloids, indicating colloids as a reservoir for these contaminants in the Yangtze estuarine system.     

Occurrence of priority organic pollutants in the fertilizers, China

The use of large quantities of chemical fertilizers is usually associated with environmental problems. A lot of work has been done on the concentrations of heavy metals and radionuclides in chemical fertilizers, but little work has focused on the occurrence of semi-volatile organic compounds (SVOCs). In this study the occurrence of 43 SVOCs listed as priority pollutants in 22 widely used-fertilizers of China was determined by gas chromatography coupled with mass spectrometry. Twenty-six SVOCs were detected with different detection frequencies and concentrations. The most abundant compounds were phthalic acid esters (PAEs; ranging from 1.17 to 2795 microg kg(-1) dry weight, d.w.) and nitroaromatics (up to 9765 microg kg(-1) d.w.), followed by polycyclic aromatic hydrocarbons (PAHs; <140 microg kg(-1) d.w.) and halogenated hydrocarbons (<900 microg kg(-1) d.w.). Chlorobenzenes and haloethers occurred generally at low concentrations. There are large variations in concentrations of various compounds in different fertilizers, and the total concentrations of each class of contaminants varied widely, too. The highest levels of sum concentration for 16 PAHs, for 6 PAEs and for nitroaromatics were found in organic fertilizer containing pesticide and soil amendments. Concentrations of SVOCs in coated fertilizers (the controlled release fertilizer with coating) were considerably higher than those in the corresponding fertilizers without coating. The occurrence frequencies of SVOCs in the straight fertilizers (containing only one of the major plant nutrients) were lower than in the other fertilizers.     

Inclusion of phthalate esters by a self-assembled monolayer of thiolated cyclodextrin on a gold electrode

Complexation of phthalic acid esters (PAEs) by a self-assembled monolayer (SAM) of thiolated alpha-cyclodextrin (6-(2-mercaptoethylamino)-6-deoxy-alpha-cyclodextrin, MEA-alpha-CD) on a gold electrode was examined by a cyclic voltammetry using hydroquinone (HQ) as a probe. From the inhibitory effect of the phthalate esters on the inclusion of HQ by the surface-confined cyclodextrin (CD), the association constants (Kasn) of the esters with the immobilized CD were estimated. For comparison, the association of PAEs with free alpha-CD was examined spectrophotometrically using methyl orange as a probe. It was concluded that, in both free and surface-confined CD systems, the Kasn value increased with an increase in the length of aliphatic alcohols conjugated to phthalic acid. Furthermore, the Kasn values for PAEs in the SAM system were much larger than those in a free CD system. This could be intuitively ascribed to the steric factor for the PAEs to come out from the cavity of surface-confined CD, whose rim was in contact with the PAEs. Thermodynamic parameters indicated that the inclusion of PAEs in the SAM system was entropy-driven, which is different from the free CD system where the inclusion was favored by both enthalpy and entropy. This is partly due to the difficulties in cancellation of strain energy by the inclusion into the cavity of the densely fixed CD (97% of the calculated maximum) and partly due to the reduction of hydrogen bonding between the PAEs and the surface-confined CD. Desolvation of the PAEs and CD by the friction at the penetration into the cavity of CD, which was rigidly fixed to the electrode, might also contribute to the positive entropy change. These factors might emphasize the apolar factor of binding to be characterized by a favorable entropy change in the immobilized CD system.     

RoHS Regulation: Challenges in the Measurement of Substances of Concern in Industrial Products by Different Analytical Techniques

The European Union’s as well as India’s reduction of hazardous materials (RoHS) directives state that producers of certain categories of electrical and electronic equipments will not be able to offer for sale any product that contains any of hazardous substances: Cd, Pb, Hg, Cr⁶⁺, polybrominated biphenyls (PBB), polybrominated diphenyl ethers (PBDE), bis(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), dibutyl phthalate (DBP) and diisobutyl phthalate (DIBP) beyond the specified limits. Allowable concentration levels in any homogeneous material contained within a product are extremely low: 0.01% for Cd and 0.1% for other substances by weight. These substances when present in quantities in excess of the permissible limits are considered hazardous and damaging to the environment and human health. With the introduction of the RoHS Directive many manufacturing companies in the world are pursuing chemical testing as a means to identify and quantify these hazardous substances. This article presents various testing methods that are currently available to the manufacturing firms who need to generate data to prove that their products are compliant to the RoHS directive. The utility of portable X-ray fluorescence spectrometer (XRF) and also the potential of laser-induced breakdown spectrometer (LIBS) for rapid screening applications is described. For quantitative determination of Pb, Cd, Hg and Cr, the role of instrumental analytical techniques such as atomic absorption spectrometry, XRF, instrumental neutron activation analysis, inductively coupled plasma optical emission spectrometry, the inductively coupled plasma mass spectrometry (ICP-MS), LIBS and the potential of the new analytical technique, microwave plasma atomic emission spectrometry is discussed. Applicability of hyphenated techniques such as HPLC-ICP-MS for Cr⁶⁺, GC–MS for the determination of PBB, PBDE and phthalates, and the importance of certified reference materials, challenges and future trends are presented.     

Evaluation of the effect of the concentration of plasticizer di(2-ethylhexyl) phthalate on the quantity of residual monomer vinyl chloride in PVC chest drainage tubes

The effect of amount of plasticizer di(2-ethylhexyl) phthalate (DEHP) amount on the amount of residual monomer vinyl chloride (VC) was determined in samples of plasticised polyvinyl chloride (PVC) with different concentration of plasticiser (22.32-33.05%), before and after sterilisation by a titrimetric method. The titrimetric method was used to determine the VC concentration in a KMnO4 solution where the samples were kept immersed under the same conditions for 2 h. The influence of PVC film extracts with different amounts of DEHP on mouse fibroblast cells L-929 in a culture medium was evaluated by using quantitative tests: the amount of cells (protein determination), viability (MTT test) and proliferation (incorporation of bromodeoxyuridine (BrDU). The amount of vinyl chloride before and after heat sterilisation at 120 degrees C for 30 min was found to be almost the same for all samples and without any dependence on the concentration of DEHP. The extracts of the PVC films which were tested have no toxic effect on cells in a culture medium.     

武汉天兴洲公铁两用长江大桥关键技术研究

天兴洲公铁两用长江大桥是北京至广州客运专线在武汉跨越长江的重要桥梁,其主桥为主跨504m的双塔三索面三主桁斜拉桥,铁路、公路分上下两层布置。重点介绍武汉天兴洲公铁两用长江大桥结构体系、主桁结构、基础选型和施工等关键技术及研究成果。     

邻苯二甲酸二丁酯在加工中的变化及膳食暴露评估

目的选取萝卜为研究对象,研究食用加工对萝卜中邻苯二甲酸二丁酯(DBP)残留量及膳食暴露评估的影响。方法采用盆栽种植、模拟餐前加工和液相色谱检测方法,研究漂烫、腌制和干制处理对萝卜中DBP残留及膳食暴露的影响。结果经漂烫、腌制和干制处理后均会对DBP残留量有明显的影响,溶度参数、水分散失和DBP挥发是影响萝卜中DBP含量的3个关键因子。在漂烫加工中,DBP残留量和加工因子随着时间的增加都呈逐渐减小的趋势,消除率为0.96%～45.54%;在腌制加工中,DBP残留量和加工因子随着时间的增加呈先减小后逐渐增加的趋势,消除率为1.36%～44.74%;在干制加工中,DBP残留量和加工因子随着时间的增加呈先增加后逐渐减小的趋势,考虑到干制加工中水分会流失,通过校正含水量后消除率可达82.06%。对DBP残留量进行膳食暴露评估的结果表明,对采用漂烫、腌制和干制等3种加工方式加工后的DBP残留量比用初始值评估值最高可分别降低45.54%,44.73%和24.32%。结论适当的食用加工方式可以有效降低萝卜中DBP的残留量,提高萝卜食用的安全性,而引入加工因子后膳食暴露评估结果会更接近真实值。     

5-Chloro-2-hydroxyaniline-copper(II) coprecipitation system for preconcentration and separation of lead(II) and chromium(III) at trace levels

A separation-preconcentration procedure based on the coprecipitation of lead(II) and chromium(III) ions with copper(II)-5-chloro-2-hydroxyaniline system has been developed. Effects of pH, sample volume and interferences on the recovery of the metal ions were investigated. The detection limits corresponding to three times the standard deviation of the blank were found to be 2.72 microg L(-1) for lead and 1.20 microg L(-1) for chromium. The preconcentration factor is 50. The effectiveness of the present method was assessed by determining analyte metals in GBW 07309 stream sediment and NIST SRM 1633b coal fly ash certified reference materials. The method was successfully applied to the determination of trace lead and chromium in environmental samples.     

Slurry sampling-microwave assisted leaching prior to hydride generation-pervaporation-atomic fluorescence detection for the determination of extractable arsenic in soil

A flow injection-pervaporation method, where the sample was introduced as slurry, has been developed for the continuous derivatization and determination of arsenic in soil by hydride generation-atomic fluorescence spectrometry. The removal of arsenic is achieved with the help of a microwave digestor, which facilitates an on-line leaching in the flow injection manifold. Slurries, prepared by mixing the soil (particle size <65 microm) with 6 mol L(-)(1) HCl, were magnetically stirred for 3 min, and while stirring, the pump aspirated the aliquot and filled the loop (500 microL) of the injection valve. An industrial soil and five types of soil (sandy, clayey, slimy, limy, organic) were selected for the optimization of the leaching and determination steps of arsenic, respectively. The results obtained from three certified reference materials [stream sediment GBW 07311 (188 microg/mL As), river sediment CRM 320 (76.7 microg/mL As), and soil GBW 07405 (412 microg/mL As)] using direct calibration against aqueous standards demonstrate the reliability of the method. The relative standard deviation for within-laboratory reproducibility was 4.5%.