胞外多聚物在厌氧污泥颗粒化成核过程中的特性

以模拟啤酒废水为底物在IC反应器中进行厌氧污泥颗粒化培养,并对污泥颗粒化过程中胞外多聚物(EPS)的主要成分变化及其与细胞表面疏水性和Zeta电位之间的相互关系进行分析,以此来阐述EPS对污泥颗粒化成核的作用。研究结果表明,好氧剩余污泥在经过56 d的培养后,平均粒径由接种时的54.72μm增长到103.46μm,实现了厌氧污泥颗粒化成核过程;EPS蛋白质含量(PN)在颗粒化过程中逐渐由接种时的18.1 mg/g增至54.3 mg/g,而EPS多糖含量(PS)则无明显变化;此外,PN/PS与污泥平均粒径、细胞表面疏水性(RH)以及Zeta电位之间呈正相关关系,相关系数分别为0.9727、0.9593和0.9274。由此可推测:厌氧污泥颗粒化成核过程的主要作用成分为胞外蛋白质,其可以改变污泥细胞表面疏水性和Zeta电位,从而在厌氧污泥颗粒化过程中有着重要的促进作用。     

Heterogeneous reactions of suspended parathion, malathion, and fenthion particles with NO(3) radicals

Organophosphorus pesticides (OPPs) emit into the atmosphere in both gas and particulate phases via spray drift from treatments and post-application emission, but most of their degradations in the atmosphere are not well known. In this study, the heterogeneous reactions of nitrate (NO₃) radicals with three typical OPPs (parathion, malathion, and fenthion) absorbed on azelaic acid particles are investigated using an online vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The reaction products observed with the VUV-ATOFMS are identified on the basis of GC/MS analysis of the products in the reaction between NO₃ radicals and the coating of the pesticide. Paraoxon is identified as the only product of parathion; malaoxon and bis(1,2-bis-ethoxycarbonylethyl)disulfide as the products of malathion; fenoxon, fenoxon sulfoxide, fenthion sulfoxide, fenoxon sulfone, and fenthion sulfone as the products of fenthion. The degradation rates of parathion, malathion, and fenthion under the experimental conditions are 5.5 × 10⁻³, 5.6 × 10⁻², and 3.3 × 10⁻² s⁻¹, respectively. The pathways of the heterogeneous reactions between the three OPPs and NO₃ radicals are proposed. The experimental results reveal the possible transformations of these OPPs through the oxidation of NO₃ radicals in the atmosphere.     

BDE-47 sorption and desorption to soil matrix in single- and binary-solute systems

Three loamy-clay soil samples (LC1-3) with different properties were collected as the geosorbents to preliminarily investigate the sorption and desorption of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) in single system and binary system with the presence of decabromodiphenyl ether (BDE-209), which can provide information in order to further understand the sorption mechanisms and evaluate the adsorption sites. A concentration of 10 μg L⁻¹ BDE-209 suppressed the sorption of BDE-47, and the trend became more and more significant with the increase of BDE-47 equilibrium concentration, however, BDE-47 caused no competitive effect on BDE-209 sorption, which was related with the better accessibility of more hydrophobic molecules to adsorption sites. In the binary system, nonlinearity of the BDE-47 sorption isotherms for the three samples changed in different ways, which originated from the varied soil properties. Desorption hysteresis was observed in all cases, which was estimated due to irreversible surface adsorption between sorbent and sorbate. BDE-209 made desorption of BDE-47 more hysteretic from soil samples, which was estimated to be ascribed to the accelerated sorbent state transition and new sites creation caused by BDE-209 sorption.     

小区生活污水的治理方案

对小区排污状况进行现场调查、分析和试验的基础上,综合对比目前处理小区生活污水的几种常用工艺,结合本小区的实际情况,提出用A／O法治理该小区的生活污水,治理后的废水出水水质达到国家废水综合排放标准(GB8978—96)二级标准,并且部分回收再利用。     

典型医化园区废气和环境空气中挥发性有机物污染特征

对典型医化园区中的挥发性有机物(VOCs)污染特征进行研究,采用便携式气相色谱质谱法监测园区及周边14个点位的环境空气,大气预浓缩气相色谱质谱法监测10个点位排气筒中废气。结果表明,废气中非甲烷总烃为1. 77～218 mg/m3,环境空气中甲苯、二氯甲烷、丙酮、乙酸乙酯、四氢呋喃的质量浓度分别为0. 048～0. 833,0. 022～3. 07,0. 011～0. 312,0. 004～0. 754和0. 004～0. 529 mg/m3;废气和环境空气中均检出含量较高的芳香烃、卤代烃、酯类、酮类等化合物,以及园区特征的氟苯类和噻吩类化合物。园区环境空气明显受到工业源VOCs污染,分布趋势为生产越密集区域VOCs值越高,经过园区后沿着风向逐渐降低,园区下风向11 km处可测到园区特征氟苯类物质。     

橡胶生产企业安全评价方法的综合应用

本文结合橡胶生产企业的特点,探讨了橡胶生产企业安全评价方法的综合应用模式:预先危险性分析法;风险矩阵指数矩阵法;道化学火灾、爆炸指数评价法;故障树分析法;安全检查表法.分析各种安全评价方法的特点,以及综合应用的效果.     

四川省农业生产环境因素-化肥施用状况宏观分析

本文首次提出“区域化肥施用负荷”、“化肥施用相对生产力”、“化肥施用相对适宜度”等概念及研究方法,用于四川省化肥施用状况宏观分析。四川全省化肥施用量F=228．86kg／hm^2,全省21个市州中自贡、攀枝花、德阳、绵阳、遂宁、眉山、雅安和巴中等8个市F〉250kg／hm^2,其中攀枝花市达到457kg／hm^2;全省5个农业区中,成都平原区F值最高,达285．63kg／hm^2。四川省化肥施用负荷H=4704kg／km^2,自贡、德阳、遂宁、内江等4市H值是全省H值4倍以上,自贡、遂宁2市甚至达5倍以上;成都平原区、盆地丘陵区H值分别是17491kg／km^2和16309kg／km^2,远远高于其他地区。全省化肥施用相对生产力R=20．26kg,攀枝花市R=12．11kg,是全省最低的;盆地丘陵区R=20．16kg,其余地区R值均高于全省的。全省近10年平均化肥施用相对适宜度T=3．19作为评价基准,攀枝花市T=5．22,是全省最高的,属化肥施用高度过量;各农业区中,盆地丘陵区T=3．47,盆周山地区T=3．28,属化肥施用轻度过量,其余地区基本适宜。     

Trend, abrupt change, and periodicity of streamflow in the mainstream of Yellow River

The Yellow River is the second largest river in China. The annual runoff of which is only about 2 % of China’s total, but contributes to 9 % of China’s GDP and directly supports 12 % of the population. Today, the water shortage in the Yellow River basin has been aggravated due to rapid population growth and global warming. In order to best maximize water resources management, the natural and observed streamflow series from six hydrologic gauging stations (Guide, Lanzhou, Hekou, Sanmenxia, Huayuankou, and Lijin) are obtained, and the linear regression, Mann–Kendall test, and wavelet transform methods were used to detect the characteristic of streamflow variation from 1956 to 2007. The results show that: (1) both the natural streamflow and observed streamflow present a downward trend over the past 52 years, and the trends are intensified downstream; the decreasing rate of observed streamflow is more rapid than that of the natural streamflow; (2) most of the abrupt changes in natural streamflow and observed streamflow appear in the late 1980s to early 1990s through the result of the Mann–Kendall test; and (3) other than the Guide station, the streamflows at the rest of the stations appear to have strongest periodicity of 19–21 years with a 52-year scale. The results of this study imply that less precipitation and warmer climate in the basin are the primary factors that cause this decreasing trend of natural streamflow. Additionally, the rapid ascent of water consumption by human being results in the reduction of observed streamflow further. Furthermore, human activities like reservoir construction, soil and water conservation measures, etc. influence the streamflow as well. It is recommended that the society takes some effective countermeasures to cope with the water shortage.     

环境中多溴联苯醚(PBDEs)的代谢转化研究现状

多溴联苯醚(PBDEs)作为一种溴系阻燃剂(BFRs),在多种环境介质和生物体内广泛存在且浓度逐年增加,因而越来越多地受到研究者关注.综合PBDEs各方面研究报道,认为其在环境中存在生物和非生物两种转化方式.非生物转化主要是光降解,即PBDEs在光照条件下可通过自由基反应脱溴生成低溴同系物及多溴联苯呋喃(PBDFs).生物转化则包括微生物转化、生物体内转化和生物体外代谢,其转化代谢途径除脱溴外,还有醚键断裂、羟基化和羟基化/脱溴等.对PBDEs在环境中不同转化方式的转化速率、转化途径和转化产物等的研究现状进行综述,对今后PBDEs在环境中归趋、生态风险和健康评价研究将起到一定的指导作用.     

Bioavailable phosphorus transport from a hillslope cropland of purple soil under natural and simulated rainfall

To further understand the mechanism of bioavailable total P (BAP) and bioavailable dissolved P (BDP) transport by overland and subsurface flow, we exposed a runoff plot 4.5 m long × 1.5 m wide × 0.6 m deep to simulated and natural rainfall in order to study the effects of rainfall type, rainfall intensity, and vegetation cover on BAP and BDP transport. The results showed that vegetation cover could alleviate the discharge of overland flow and sediment transport and enhance subsurface flow. BAP transport significantly increased with elevated rainfall intensity. Vegetation cover reduced the BAP transport by overland flow and increased it by subsurface flow. BDP transport showed no significant relationship with vegetation cover and rainfall type. The bioavailable particulate P (BPP) transport by overland flow contributed to no less than 90% by weight of total BAP, and the BPP transport by subsurface flow contributed to no less than 60% by weight of total BAP. Short-time heavy rainfall caused more BAP transport and accelerated non-point source pollution.