Multiresidue analysis of organophosphate and pyrethroid pesticides in duplicate-diet solid food by pressurized liquid extraction

An analytical method was developed for determining organophosphate pesticides (OPP) and pyrethroid pesticides (PYR) in duplicate-diet solid food. The method consisted of pressurized liquid extraction (PLE) with dichloromethane followed by cleanup with gel permeation and solid phase extraction columns and gas chromatography/mass spectrometry (GC/MS) analysis. Quantitative recoveries (73-117 %) of the target pesticides were obtained for spiked duplicate-diet food samples. The percent standard deviation (% RSD) of replicate food samples was within ± 20 %. Another method was developed for determining a common OPP metabolite, 3, 5, 6-trichloro-2-pyridinol (TCP) in duplicate-diet food. The method consisted of a PLE with methanol followed by liquid-liquid partitioning, derivatization, and GC/MS analysis. Recoveries of TCP ranged from 83 to 101 % for spiked duplicate-diet food samples. The % RSD of replicate food samples was within ± 15 %. The results confirmed that these methods are reliable and robust, and that they can be used in routine analysis. In addition, a storage stability study for a common OPP, chlorpyrifos (CPF), in solid food samples was performed. The fortified (15)N-(13)C-labeled CPF was stable over 16 mo storage at -20° C in the dark. The developed analytical methods were successfully applied to 278 duplicate-diet food samples from preschool children, demonstrating that these methods are robust and suitable for routine analysis in future exposure monitoring studies.     

类Fenton反应对偶氮染料橙黄II的脱色研究

以橙黄II染料溶液为研究对象,通过正交实验确定了Fe-NTA/H2O2构成的类Fenton反应中各影响因子的最佳操作条件为:[H2O2]=20 mmol/L,[Fe-NTA]=2.5 mmol/L,pH=3。同时考察了反应时间、溶液pH值、H2O2浓度、Fe-NTA浓度对脱色效率的影响。实验表明脱色反应在30 m in内基本完成,类Fenton试剂能在较宽的pH范围内保持较好的脱色效果,而且在pH=6时,类Fenton试剂比传统Fenton试剂的脱色效率提高约75%。增加双氧水浓度可以提高橙黄II溶液脱色率,但超过20 mmol/L后效果提高不明显。在0.5~2.5 mmol/L的范围内,Fe-NTA浓度对脱色效果的影响不显著。     

气象条件对沈阳市环境空气臭氧浓度影响研究

利用2013年沈阳市环境空气监测点位臭氧监测数据,分析沈阳臭氧浓度变化特征,结合气象资料分析了其对臭氧浓度的影响。结果表明,沈阳市不同区域臭氧浓度变化特征基本一致。臭氧浓度日变化呈单峰趋势,最大值出现在14:00左右,最小值出现在6:00左右;臭氧浓度变化具有明显的季节特征,夏季臭氧浓度最高,春秋次之,冬季最低;臭氧浓度受温度、风速、湿度、能见度、天气情况影响,臭氧浓度变化是多因素共同作用的结果。     

官厅水库典型入库河流(洋河)表层沉积物重金属赋存形态特征

官厅水库曾是北京市重要的饮用水源地之一,洋河作为官厅水库重要入库河流,沉积物污染直接影响水库的水质安全.以洋河水系表层沉积物为研究对象,利用BCR三步连续提取法分析沉积物中Cd、Cr、Cu、Ni、Pb和Zn形态特征,并基于重金属形态的评价方法(次生相原生相分布比值法-RSP和风险评估指数法-RAC),评价了洋河水系表层沉积物中重金属的污染程度与风险水平.结果表明,在整体研究区域,6种重金属均以残渣态(B4态)为主,在次生相中(除B4以外的其他3种形态),Cd、Cu、Ni、Pb和Zn均以可还原态(B2态)为主,Cr以可氧化态(B3态)为主.在空间分布上,Cd在干流中游段和支流清水河段以B2态为主;Zn在干流中游段以B2态和弱酸提取态(B1态)为主,在支流清水河段以B2态为主.RSP结果表明,洋河水系表层沉积物中Cd和Zn为轻度污染,Cr、Ni、Cu和Pb无污染.但Cd和Zn在支流清水河段均为重度污染等级,其可能主要来源于区域化工原料及化学品制造行业.RAC结果表明,整体上洋河水系表层沉积物中Cd和Zn对水环境构成中等风险,Ni和Cu构成了低风险,而Cr和Pb基本无风险.     

不同粒径易自燃煤常温氧化实验研究*

为探究易自燃煤在常温条件下的氧化特性,自行设计煤常温封闭氧化实验装置,采用实验研究与回归分析2种方法,分析易自燃煤发生氧化反应的气体变化过程,探究3种粒径煤样在20 ℃有限空间内的耗氧与产气特征。结果表明:易自燃煤样在16 d常温封闭氧化过程中,容器内O2体积浓度呈指数衰减、CO和CO2体积浓度呈指数增长的变化规律;在0.06~0.83 mm范围内,粒径越大,易自燃煤耗氧速率越大,CO和CO2产生速率则先增大后减小;介于中间的粒径为0.13~0.25 mm易自燃煤氧化反应最强烈,更容易发生氧化。研究结果对揭示生产环境温度下煤粒粒径对煤自燃的影响有一定的意义。     

Species of Trace Metals, Organic Residues and Humic Substances in Sediments From the Taiwan Erhjin River and Coastal Areas

Total organic carbon, humic substances, and the species of trace metals (including Cu, Zn, Pb, Cd, Cr, Mn and Fe) in six and seven phases, such as bioexchangeable (P1), skeletal (carbonates, P2), easily reducible (Fe and Mn oxides, P3), moderately reducible (crystalline Mn oxides, P4), organic matters with sulphides (P5), and detritus with minerals (P6) as well as organic with humic substances (PB4) and organic residues (PB6), were analyzed in sediments from the Taiwan Erhjin coastal (including river and estuarine) area, where places we found the copper pollution. Results indicate that higher percentages of P1 and P2 for copper, zinc, lead, cadmium and manganese in samples collected in March and September of 1990 were much higher than those in P3-P6. High percentages of chromium and iron in samples respectively collected in March and September of 1990 were found in P6. for the seven phase analysis, higher percentages of copper species in PB4 and PB6 as well as iron species in PB7 were observed. On the other hand, purified humic acid with the high contents of manganese and iron in humic acid as well as purified fulvic acids were generally found at the upstream stations; and low values at coastal stations. However, extremely high copper (as high as 1750μg g^-1, dry weight in fulvic acid and 820μg g^-1 in humic acid) and lead (821μg g^-1 in humic acid) concentrations with relatively high manganese and iron concentrations were observed in humic substances from the station near the copper recycling area. Comparing the results obtained from the Antarctic Ocean sediments with those from the Taiwan Erhjin Chi coastal sediments, the human impacts on the latter are evaluated.     

Biotrickling filtration of airborne styrene: A comparison of filtration media

This study compares the performances of fern and plastic chips as packing media for the biofiltration of a styrene-laden waste gas stream emitted in a plant for the manufacture of plastic door plates. Fern chips (with a specific surface area of 1090 m² m^?3) and plastic chips (with a specific surface area of 610 m² m^?3) were packed into a pilot-scale biotrickling filter with a total medium volume of 50 L for the performance test. Field waste gas with styrene concentrations in the range of 161–2390 mg Am^?3 at 28–30 °C) was introduced to the bed and a fixed empty-bed retention time (EBRT) of 21 sec, a volumetric gas flow rate of 8.57 m³ hr^?1, and superficial gas velocity of 53.6 m hr^?1 were maintained throughout the experimental period. Nutrients containing metal salts, nitrogen, phosphorus, and milk were supplemented to the filters for maintaining the microbial activities. Results reveal that the biotrickling filter developed in this study had the highest styrene monomer (SM) elimination capacities (170 g m^?3 hr^?1 for fern-chip packing and 300 g m^?3 hr^?1 for plastic-chip packing) among those cited in the literature. The plastic medium is a favorable substitute for endangered fern chips. The thermal-setting nature of plastic chips limits their recycle and reuse as raw materials, and the study provides an opportunity for the utilization of the materials.

Implications: Biotreatment of contaminants in air streams offers an inexpensive and efficient alternative to conventional technologies. Biofiltration has a great potential for the degradation of gas-borne styrene and total hydrocarbon (THC) removal efficiency of around 80%. The objective of this research was to compare the performances of fern chips and a kind of plastic chips as packing media for biofiltration of the styrene-laden waste gas stream emitted from cutting operations of stripes of premixed unsaturated polyester (UP) and styrene paste before hot-pressing operations for making plastic door plates. From a practical point of view, the plastic medium can be a good substitute medium for fern chips, which has been declared as a protected plant. This study provides an experimentally verified model for the design and operation of such biotreatment systems.     

环戊烯臭氧化反应瞬变物种产生机制

大气中烯烃臭氧化反应产物是二次有机气溶胶(SOA)形成的重要前体物. 运用自行组建的低温基质隔离系统研究环戊烯臭氧化反应的瞬变物种产生机制. 采用程序升温方法,将温度从6 K升至115 K,用傅里叶红外光谱仪检测不同温度下生成的活性中间体,并将试验值与理论计算值、文献报道值进行对比,以确定中间体构型. 结果表明:环戊烯臭氧化反应生成的中间体——POZ(初级臭氧化物)、SOZ(二次臭氧化物)和CI(一分子羰基氧化物和一分子醛或酮)被成功检测到. 其中,POZ的特征吸收峰在705和946 cm-1处,对应O—O—O反对称伸缩振动和环变形振动;SOZ特征吸收峰在939 cm-1处,对应C—O伸缩振动;CI的特征吸收峰在1 733和853 cm-1处,分别对应CO伸缩振动和O—O伸缩振动. 据此,环戊烯臭氧化反应遵循Criegee机制. 采用4种量子化学计算方法——B3LYP/6-311++G(d,2p)、B3LYP/6-311++G(3df,3pd)、MP2/aug-cc-pvdz和PW91PW91/6-311++G(3df,3pd),计算POZ、SOZ和CI特征吸收峰的振动频率,其中POZ在705 cm-1处吸收峰的振动频率计算值分别为725、698、703、680 cm-1;SOZ在1 030 cm-1处吸收峰的振动频率计算值分别为1 017、1 018、1 025和993 cm-1;CI在1 733 cm-1处吸收峰的振动频率计算值分别为1 796、1 803、1 732和1 745 cm-1.表明MP2/aug-cc-pvdz计算的特征振动频率与试验值最接近.      

鲍鱼对2种多环芳烃的富集动力学研究

为探究多环芳烃(PAHs)在海洋生物体内富集过程,选择皱纹盘鲍(Haliotis discus hannai)作为受试生物,应用半静态双箱动力学模型,分别考察了3-甲基菲和9,10-甲基蒽2种多环芳烃在皱纹盘鲍体内的富集动力学过程,通过非线性拟合获得鲍鱼对2种多环芳烃的吸收速率常数(K_1)、释放速率常数(K_2)、生物富集因子(BCF),以及平衡状态下鲍鱼体内2种多环芳烃的含量(Cmax)、生物学半衰期(t_(1/2))等动力学参数。结果表明,鲍鱼对9,10-甲基蒽富集动力学参数K_1、K_2、BCF、Cmax、t_(1/2)的平均值分别为4.9437、0.406、13.59、790.03μg·L~(-1)、3.78 d。鲍鱼对3-甲基菲富集动力学参数K_1、K_2、BCF、Cmax、t_(1/2)的平均值分别为2.3023、0.367、5.97、354.37μg·L~(-1)、3.13 d。鲍鱼在不同浓度下对3-甲基菲和9,10-甲基蒽的生物富集过程均符合双箱动力学模型。     

河南省服务业发展的主要问题与对策研究

通过分析河南省近年来服务业发展状况的统计数据,在开展调查研究的基础上,全面分析了河南省服务业在发展过程中存在的主要问题.针对这些问题,结合河南省服务业的实际发展状况和自身特点,从政府引导、结构优化、重点建设、人才培养、集聚区建设五个方面提出了相关对策建议.