Serious BTEX pollution in rural area of the North China Plain during winter season

Atmospheric BTEX compounds(benzene, toluene, ethylbenzene and xylenes) in a rural site of the North China Plain(NCP) were preliminarily investigated in winter, and the outdoor concentrations(25.8–236.0 μg/m3) were found to be much higher than those reported in urban regions. The pollution of BTEX inside a farmer's house was even more serious, with combined concentrations of 254.5–1552.9 μg/m3. Based on the ratio of benzene to toluene(1.17 ± 0.34) measured, the serious BTEX pollution in the rural site was mainly ascribed to domestic coal combustion for heating during the winter season. With the enhancement of farmers' incomes in recent years, coal consumption by farmers in the NCP is rapidly increasing to keep their houses warm, and hence the serious air pollution in rural areas of the NCP during winter, including BTEX, should be paid great attention.     

Assessment of cadmium content of potato grown in Weining County,Guizhou Province,China

A total of 54 soil and 54 potato samples have been collected from Weining County to evaluate the accumulation of cadmium in potatoes. The concentrations of the total Cd and the available Cd in the soil samples have been detected. The total concentrations of Cd were from 0.41 to 10.0 mg/kg with an average value of 2.60 mg/kg in soil. The concentrations of available Cd in the soil were 0.07 to 3.47 mg/kg with an average value of 0.59 mg/kg. The concentration of the available Cd showed a good linear positive correlation with the total Cd content in the soil. For the 54 potato samples, the Cd concentrations were from 0.023 to 0.18 mg/kg with an average value 0.083 mg/kg (fresh weight).The bioconcentration factor (BCF) values of Cd in potatoes, based on dry weight, were from 0.02 to 0.96 with an average value 0.24. The uptake of cadmium by plants is dependent on various soil and environmental factors. A regression model to predict the concentration of cadmium in Weining potatoes based on soil properties and elevation was developed. The results showed the elevation and the soil pH played an important role and had a negative influence on the uptake of Cd by potato in Weining County. The mean intake of Cd by adults through consumption of potato from Weining would be 5.9 μg/day, and it is well below the provisionally tolerable daily intake for Cd (70 μg/day).     

原料对餐厨垃圾堆肥产品的影响及其绿地应用适宜性分析

以果蔬残余(VW)、食物残余(FL)及混配餐厨垃圾(MIX)为原料,用生化处理机进行堆肥处理,分别测定比较堆肥产品的肥力特性和污染特性,并探讨其绿地应用适宜性。研究表明,总氮、总磷和有机质含量MIX>VW>FL,均值分别为23.8、3.88和525 g/kg,符合相关标准;重金属及可挥发性有机污染物含量很低,除FL产品的镍含量外均未超标;氯离子、动植物油含量均值分别高达11.1 g/kg和37.9 g/kg,施用于绿地时应控制用量;含水率、杂质含量较高,有臭味;种子发芽指数(GI)除MIX外均未达到50%。可见,原料对堆肥终产物有显著影响,VW比FL更适宜用于生产肥料,MIX产品比单一成分堆肥产品养分更均衡,毒性更低;餐厨垃圾肥料的绿地应用具有广阔前景,但需严格控制盐分及油脂含量,并改善堆肥工艺以提高产品质量。     

Risk assessment and monitoring of dinotefuran and its metabolites for Chinese consumption of apples

Residues of dinotefuran and its metabolites, 1-methyl-3-(tetrahydro-3-furylmethyl)urea (UF) and 1-methyl-3-(tetrahydro-3-furylmethyl)guanidine (DN), in apple were investigated using a “QuEChERS” (quick, easy, cheap, effective, rugged, safe) pretreatment and liquid chromatography–tandem mass spectrometry. Limits of detection (LODs) and quantification (LOQs) of dinotefuran, UF, and DN in apples were 0.011–0.960 and 0.037–3.200 μg/kg, respectively. The average recoveries of dinotefuran, UF, and DN in apple ranged from 70.0 to 83.6% with relative standard deviations less than 13%. A formulation of 20% water-dispersible dinotefuran granules was sprayed at 1–1.5-fold the recommended dose 3–4 times on apple trees. Total terminal residues of dinotefuran in apple were less than 2 mg/kg, which is the maximum residue limit (MRL) set by Japan. When following the recommended application guidelines, dinotefuran is unlikely to present significant health concerns to the Chinese population because the risk quotient (RQ) is less than 100%. This work could provide guidance for the safe use of dinotefuran and serve as a reference for the establishment of a maximum residue limit of dinotefuran in apple in China.     

决策环境风险评价的研究进展

对环境风险评价的基本概念、发展历程以及主要的技术路线和方法作了总结,介绍了决策环境风险评价的概念和应用,指出当前决策环境风险评价研究中存在的主要问题。     

Characteristics of atmospheric volatile organic compounds in urban area of Beijing: Variations, photochemical reactivity and source apportionment

Atmospheric volatile organic compounds (VOCs) were observed by an on-line gas chromatography-flame ionization detector monitoring system from November 2016 to August 2017 in Beijing. The average concentrations were winter (40.27 ± 25.25 μg/m³) > autumn (34.25 ± 19.90 µg/m³) > summer (32.53 ± 17.39 µg/m³) > spring (24.72 ± 17.22 µg/m³). Although benzene (15.70%), propane (11.02%), ethane (9.32%) and n-butane (6.77%) were the most abundant species, ethylene (14.07%) and propene (11.20%) were the key reactive species to ozone formation potential (OFP), and benzene, toluene, ethylbenzene, m-xylene + p-xylene and o-xylene (54.13%) were the most reactive species to secondary organic aerosol formation potential (SOAFP). The diurnal and seasonal variations indicated that diesel vehicle emission during early morning, gasoline vehicle emission at the traffic rush hours and coal burning during the heating period might be important sources. Five major sources were further identified by positive matrix factorization (PMF). The vehicle exhaust (gasoline exhaust and diesel exhaust) was found to be contributed most to atmospheric VOCs, with 43.59%, 41.91%, 50.45% and 43.91%, respectively in spring, summer, autumn and winter; while solvent usage contributed least, with 11.10%, 7.13%, 14.00% and 19.87%, respectively. Biogenic emission sources (13.11%) were only identified in summer. However, both vehicle exhaust and solvent usage were identified to be the key sources considering contributions to the OFP and SOAFP. Besides, the contributions of combustion during heating period and gasoline evaporation source during warm seasons to OFP and SOAFP should not be overlooked.     

北京市城区春季大气挥发性有机物污染特征

"2+26"城市联防联控措施的实施及北京市产业结构的调整,使得北京市大气中VOCs（volatile organic compounds,挥发性有机物）质量浓度、组成特征及来源发生了变化.运用AirmoVOC（GC-866）在线自动监测仪对2017年3-5月北京市城区大气中的VOCs进行观测.结果表明:①北京市城区春季大气中ρ（TVOCs）（TVOCs为总挥发性有机物）为34.36 μg/m3,ρ（烷烃）、ρ（芳香烃）、ρ（烯烃）、ρ（炔烃）分别占ρ（TVOCs）的57.13%、33.18%、7.54%、2.15%.质量浓度最高的前3位VOCs物种分别为苯、丙烷和乙烷,其质量浓度分别为5.97、3.51、2.63 μg/m3.②ρ（TVOCs）的日变化有3个较明显的峰值,分别出现在05:00、11:00和23:00,ρ（TVOCs）最低值出现在18:00,并且夜间ρ（TVOCs）高于白天.VOCs日变化特征表明,北京市VOCs污染受凌晨时段柴油车尾气排放和早晚交通高峰期汽油车尾气排放的影响较为明显.③春季VOCs的OFP（ozone formation potential,臭氧生成潜势）分析表明,芳香烃对OFP的贡献率（44.22%）最大,其次是烯烃（31.06%）,最后是烷烃（23.86%）;北京市VOCs污染的关键活性组分是丙烯、正丁烷、环戊烷、苯、甲苯、二甲苯.④PMF（正矩阵因子分析法）分析表明,溶剂使用源是北京市春季大气中VOCs最主要的排放源,对TVOCs的贡献率为39.06%,其次是移动源（33.79%）和油气挥发源（17.85%）,燃烧源的贡献率（9.30%）最低.研究显示,控制移动源、溶剂使用源和燃烧源的排放是控制北京市环境空气中VOCs污染的关键.      

Dissipation and residue of metalaxyl and cymoxanil in pepper and soil

A simple and accurate method of determining metalaxyl and cymoxanil in pepper and soil was developed by ultra-performance liquid chromatography–photodiode array detection. The limits of detection were 0.015 mg/kg for metalaxyl and 0.003 mg/kg for cymoxanil. The limits of quantification were 0.05 mg/kg for metalaxyl in pepper and soil as well as 0.01 mg/kg for cymoxanil in pepper and soil. Recoveries of pepper and soil were investigated at three spiking levels and ranged within 77.52 to 102.05 % for metalaxyl and 87.15 to 103.21 % for cymoxanil, with relative standard deviations below 9.30 %. For field experiments, the half-lives of metalaxyl were 3.2 to 3.9 days in pepper and 4.4 to 9.5 days in soil at the three experimental locations in China. At harvest, pepper samples were found to contain metalaxyl and cymoxanil well below the maximum residue limit MRLs of the European Union (EU) following the recommended dosage and the interval of 21 days after last application.     

Contamination,spatial distribution,and source contribution of persistent organic pollutants in the soil of Guiyang city,China: a case study

Environmental Geochemistry and Health - The contamination of persistent organic pollutants (POPs), including dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and polycyclic...     

Enantioselective hydrolysis and photolysis of mandipropamid in different aquatic environments — evaluation of influencing factors

Environmental Science and Pollution Research - The hydrolysis and photolysis of the chiral fungicide mandipropamid were investigated, and the potential enantioselectivity of mandipropamid in...