Human health risk assessment of groundwater in Hetao Plain (Inner Mongolia Autonomous Region,China)

Groundwater quality significantly affects public health. In order to better understand groundwater suitability, a total of 887 shallow groundwater samples were collected from the Hetao Plain (HP), Inner Mongolia, China; the maximum and minimum health guideline values of each element were established in this work. Subsequently, the desirability functions (DFs) theory was employed to evaluate the human health risk of groundwater. The results indicate that 780 of the samples were unsuitable for drinking purposes due to the iron, total dissolved solids (TDS), arsenic, strontium, fluoride, and manganese concentrations present, all of which exceeded their maximum guideline value (MaGV). Only 107 samples were suitable for drinking use; however, these samples also have adverse effects on human health to some extent, due to the extremely lower concentrations of nutrient elements and existence of non-nutrient elements. Based on the observed results, groundwater that is unsuitable for drinking use must undergo bacteriological treatment prior to consumption. It was necessary for residents in the western, central, and northeastern parts of the study area are required to be supplied with certain nutrient elements, such as iron, iodine, molybdenum, manganese, and lithium. According to the human health risk assessment of groundwater, the general public can safely and reasonably consume the groundwater for drinking, agriculture irrigation, and industrial purposes.     

Preparation and utilization of molecularly imprinted polymer for chlorsulfuron extraction from water, soil, and wheat plant

A molecularly imprinted polymer (MIP) was prepared using chlorsulfuron (CS), a herbicide as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linker, methanol and toluene as a porogen, and 2,2-azobisisobutyronitrile as an initiator. The binding behaviors of the template chlorsulfuron and its analog on MIP were evaluated by equilibrium adsorption experiments, which showed that the MIP particles had specific affinity for the template CS. Solid-phase extraction (SPE) with the chlorsulfuron molecularly imprinted polymer as an adsorbent was investigated. The optimum loading, washing, and eluting conditions for chlorsulfuron molecularly imprinted polymer solid-phase extraction (CS-MISPE) were established. The optimized CS-MISPE procedure was developed to enrich and clean up the chlorsulfuron residue in water, soils, and wheat plants. Concentrations of chlorsulfuron in the samples were analyzed by HPLC-UVD. The average recoveries of CS spiked standard at 0.05~0.2 mg L(-1) in water were 90.2~93.3%, with the relative standard deviation (RSD) being 2.0~3.9% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 10 g soil were 91.1~94.7%, with the RSD being 3.1~5.6% (n=3). The average recoveries of 1.0 mL CS spiked standard at 0.1~0.5 mg L(-1) in 5 g wheat plant were 82.3~94.3%, with the RSD being 2.9~6.8% (n=3). Overall, our study provides a sensitive and cost-effective method for accurate determination of CS residues in water, soils, and plants.     

光催化处理二甲苯废气的影响因素研究

使用自制光催化反应器,以多孔型载体分别负载纳米TiO2和普通TiO2,以256～265 nm紫外光为光源,探讨了TiO2光催化处理二甲苯废气的影响因素及处理性能.结果发现,在以纳米型TiO2作为催化剂、在紫外光强为1000 W且布光均匀、风量为1000 m3/h、进口浓度350 mg/m3、通入臭氧的工况条件下运行,整个系统对二甲苯的去除率平均在90%以上.     

快速交通对城市可达性及经济联系影响研究——以湖南省为例

基于因子分析法测算了城市经济实力,运用可达性系数模型分析高速铁路和高速公路对城市可达性的影响,运用引力模型测算出快速交通对城市经济联系的影响,并利用ESDA法测度了城市经济联系的空间分异特征。结果表明:快速交通使得湖南城市整体可达性大幅提高,产生了明显的"时空压缩"效应。快速交通使边缘城市与中心地区城市可达性的差异缩小,高铁沿线城市的可达性明显优于非高铁沿线城市,高速公路扩大了高铁可达性的影响范围。快速交通使湖南省内城市间经济联系增强,强化了长沙的经济中心地位,扩大了东西部城市的经济差异,省际经济联系强度受出省通道便捷性的影响。此外,各市经济联系总量总体上具有层次性,演化上存在非均衡性。     

实时控制条件下外加碳源用于低C/N比养殖废水处理中污泥膨胀的控制研究

养殖废水是一类典型的高氨氮废水.在低C/N比进水条件下,生物处理单元内较易出现污泥膨胀现象.采用实时控制技术,建立了序批式反应器(SBR)优化硝化-反硝化控制系统,进行了外加碳源用于低C/N比养殖废水处理中的污泥膨胀控制研究.并探讨了优化控制系统对污泥膨胀的控制机制.结果表明,低C/N比进水条件下,不完全硝化-反硝化过程导致硝酸盐及氨氮的累积是低F/M条件下污泥膨胀的主要原因.根据进水水质变化,实时控制系统自动优化外加碳源投加量,可有效控制由不完全硝化-反硝化反应引起的污泥膨胀.     

TiO2光催化氧化处理偶氮染料废水的研究进展

二氧化钛具有较高的光稳定性和反应活性,可用于处理偶氮染料废水,对二氧化二钛光催化氧化的影响因素、提高二氧化钛光能化氰化处理偶氮染料废水效率的途径和比催化氧化联用处理技术进行了综述,提出今后研究重点是扩展二氧化钛对可见光的光谱响应、提高太阳光的利用率以及加强气-质联用、液-质联用技术在处理偶氮染料废水中的应用。     

Evaluation of N-acetylcysteine and glutathione as quenching agents for the analysis of halogenated disinfection by-products

Disinfection by-products(DBPs), formed from the reactions of disinfectants with natural organic matter and halides in drinking water, were considered to be cytotoxic and genotoxic, and might trigger various cancers. The relatively low concentration of DBPs in finished water(low μg/L or even ng/L levels) and the interference from water matrix inhibited in situ determination of DBPs. Moreover, the further formation and degradation of DBPs by disinfectants during the holding time(several hours to s...     

Mg/Al水滑石对水中痕量邻苯二甲酸酯的吸附动力学和热力学

研究了Mg／A1水滑石对水中痕量邻苯二甲酸二甲酯（DMP）、邻苯二甲酸二（2一乙基己基）酯（DEHP）和邻苯二甲酸二辛酯（DnOP）的吸附动力学和热力学特性。结果表明,在所研究的浓度范围内,3种邻苯二甲酸酯的吸附动力学曲线均符合准二级速率方程,DMP、DEHP和DnOP分别在600、200和200min基本达到吸附平衡;3种邻苯二甲酸酯的吸附等温线基本符合Langmuir和Freundlich吸附等温方程;在283～308K范围,pH=6．36,3种邻苯二甲酸酯初始浓度均为50μg／L时,吸附过程△H为负值且绝对值为5～12kJ／mol,表明吸附为放热过程,以表面物理吸附为主,邻苯二甲酸酯在Mg／Al水滑石上的吸附是色散力、诱导力、取向力和氢键力等多种作用力协同作用的结果。     

Spatial and seasonal variations of polycyclic aromatic hydrocarbons in Haihe Plain, China

A dynamic fugacity model was developed to simulate the spatial and seasonal variations of PAHs in Haihe Plain, China. The calculated and measured concentrations exhibited good consistency in magnitude with deviations within a factor of 4 in air and 2 in soil. The spatial distributions of PAHs in air were mainly controlled by emission while the seasonal variations were dominated by emission and gas-particle partition. In soil, the spatial distributions of PAHs were controlled by the soil organic carbon content while the seasonal variations were insignificant. The severest soil contamination was observed in Shanxi and followed by the southwest of Hebei province. Transfer fluxes of total PAHs between air and soil were calculated. The spatial distribution of air-to-soil flux was closely related to the landcover while the soil-to-air flux changed with soil organic matter content. Monte Carlo simulation was done to evaluate the uncertainty of the estimated results in air.     

V/Ce共掺杂TiO2光催化降解甲醛的实验研究

采用溶胶-凝胶法制备了不掺杂、V掺杂、Ce掺杂、V/Ce共掺杂纳米TiO2光催化剂,并将其分别负载于瓷砖上,利用X射线衍射分析（XRD）和扫描电镜分析（SEM）技术对薄膜样品的结构和形貌进行了表征。通过对甲醛的降解实验评价光催化剂的光催化活性。实验结果表明,光催化剂的负载量、共掺杂离子的掺杂量、掺杂配比、煅烧温度影响纳米TiO2的光催化活性。V/Ce共掺杂TiO2光催化剂产生了协同效应,其光催化活性优于纯TiO2和单掺杂TiO2样品。