Natural and anthropogenic factors affecting the shallow groundwater quality in a typical irrigation area with reclaimed water,North China Plain

In this study, the hydrochemical characteristics of shallow groundwater were analyzed to get insight into the factors affecting groundwater quality in a typical agricultural dominated area of the North China Plain. Forty-four shallow groundwater samples were collected for chemical analysis. The water type changes from Ca·Na-HCO₃ type in grass land to Ca·Na-Cl (+NO₃) type and Na (Ca)-Cl (+NO₃+SO₄) type in construction and facility agricultural land, indicating the influence of human activities. The factor analysis and geostatistical analysis revealed that the two major factors contributing to the groundwater hydrochemical compositions were the water-rock interaction and contamination from sewage discharge and agricultural fertilizers. The major ions (F, HCO₃) and trace element (As) in the shallow groundwater represented the natural origin, while the nitrate and sulfate concentrations were related to the application of fertilizer and sewage discharge in the facility agricultural area, which was mainly affected by the human activities. The values of pH, total dissolved solids, electric conductivity, and conventional component (K, Ca, Na, Mg, Cl) in shallow groundwater increased from grass land and cultivated land, to construction land and to facility agriculture which were originated from the combination sources of natural processes (e.g., water-rock interaction) and human activities (e.g., domestic effluents). The study indicated that both natural processes and human activities had influences on the groundwater hydrochemical compositions in shallow groundwater, while anthropogenic processes had more contribution, especially in the reclaimed water irrigation area.     

壳聚糖接枝共聚物的合成及应用研究

在N2保护下,以浓度为0.8 mmol/L硝酸铈铵为引发剂,控制壳聚糖(CTS)和丙烯酰胺(AM)质量比为mCTS∶mAM=1∶6,于50℃下接枝共聚反应3 h,得改性的壳聚糖衍生物(CAM).用IR对产物进行表征.通过对废水的处理,研究了共聚产物在絮凝、COD去除、脱色上的应用.结果表明:CAM的絮凝效果好于聚丙烯酰胺和壳聚糖,CAM对COD的去除率达到84.7%,并有较好的脱色效果.     

典型SSRIs类抗抑郁药对鱼类的毒性效应研究进展

选择性血清素再摄取抑制剂(selective serotonin reuptake inhibitors,SSRIs)是一类在临床上具有良好治疗效果的抗抑郁药物,由于使用量巨大,在水环境中频繁被检出,其潜在生态毒性效应引起人们的广泛关注.鱼类作为水生脊椎动物,具有和人类相似的神经调控系统,更易受到水体中残留的SSRIs...     

高锰酸钾预氧化后地表水中三氯甲烷生成量的预测模型研究

在饮用水处理中,适当地采用高锰钾预氧化可以降低水中的三氯甲烷生成量。本文研究了影响三氯甲烷生成量的因素,如反应时间,反应温度等,并以这些影响因素为参数通过一元线性回归等数学方法,建立了各影响因素下三氯甲烷生成量折了模型和综合预测模型。     

氯代苯及氯代酚类优先污染物好氧生物降解动力学的研究

利用测定微生物呼吸耗氧量的方法,对氯代苯及氯代酚类中的７种优先污染物,用经它们分别驯化的活性污泥对其好氧生物降解动力学进行了研究。     

水中微量甲基膦酸类化合物的树脂富集与GC／MS分析

本文使用三种阴离子交换树脂（即大孔弱碱型Ｄ－３０１－Ｒ,强碱型Ｄ－２９６,２０１Ｘ７）柱对水中微量甲基膦酸类化合物的富集方法进行了研究。含磷毒剂降解产物的水样用气相色谱／质谱法进行定性定量分析。结果表明,Ｄ－３０１－Ｒ阴离子交换树脂柱对甲基膦酸的富集回收率高于６０％。     

The effect of γ-Fe2O3 nanoparticles on Escherichia coli genome

Extensive production and application of γ-Fe₂O₃ magnetic nanoparticles (MNPs) has increased their potential risk on environment and human health. This report illustrates a genetic impact of γ-Fe₂O₃ magnetic nanoparticles (MNPs) on Escherichia coli (E. coli). After 3000-generation incubation with MNPs addition, obvious genomic variations were revealed by using repetitive extragenic palindromic PCR (rep-PCR) DNA fingerprint technique. The physicochemical interactions between MNPs and bacteria could be responsible for such genomic responses. It was revealed that Fe³⁺ concentration increased in the medium. Transmission electronic microscopy (TEM) and flow cytometry (FCM) analysis consistently demonstrated the occurrences of adsorption and membranes-internalization of MNPs outside and inside cells. Both increased Fe³⁺ ion and the uptake of MNPs facilitated Fe binding with proteins and DNA strands, resulting in enhancing the mutation frequency of E. coli. Our results would be of great help to assessing the potential impact of MNPs on human and environment.     

环境水体中四溴双酚A的HPLC-MS/MS分析方法的建立与应用

四溴双酚A(tetrabromobisphenol A,TBBPA)是目前使用量最大的溴代阻燃剂.随着它的广泛应用,已经引起了大气、水体、沉积物和土壤等环境介质及相关生态系统的严重污染.建立了环境水体中TBBPA的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法.该方法采用电喷雾电离(ESI)负离子模式进行扫描,...     

新型混凝剂聚磷氯化铝铁的表征及应用

以FeCl3·6H2O、AlCl3·6H2O和Na2HPO4·12H2O为主要原料,采用共聚工艺,制备了聚磷氯化铝铁(PPAFC)混凝剂.采用FTIR及SEM进行结构表征,推断磷酸根为与聚合氯化铝铁(PAFC)接聚,而不是磷酸盐与PAFC之间简单的物理混合.实验结果表明,以PPAFC处理含油乳化液废水、造纸废水及受污染...     

Developmental toxicity of cypermethrin in embryo-larval stages of zebrafish

Cypermethrin, a type II pyrethroid insecticide, is widely used throughout the world in agriculture, forestry, horticulture and homes. Though the neurotoxicity of cypermethrin has been thoroughly studied in adult rodents, little is so far available regarding the developmental toxicity of cypermethrin to fish in early life stages. To explore the potential developmental toxicity of cypermethrin, 4-h post-fertilization (hpf) zebrafish embryos were exposed to various concentrations of cypermethrin (0, 25, 50, 100, 200 and 400 μg L⁻¹) until 96 h. Among a suite of morphological abnormalities, the unique phenotype curvature was observed at concentrations as low as 25 μg L⁻¹. Studies revealed that 400 μg L⁻¹ cypermethrin significantly increased malondialdehyde production. In addition, activity of antioxidative enzymes including superoxide dismutase and catalase were significantly induced in zebrafish larvae in a concentration-dependent manner. To further investigate the toxic effects of cypermethrin on fish, acridine orange (AO) staining was performed at 400 μg L⁻¹ cypermethrin and the result showed notable signs of apoptosis mainly in the nervous system. Cypermethrin also down-regulated ogg1 and increased p53 gene expression as well as the caspase-3 activity. Our results demonstrate that cypermethrin was able to induce oxidative stress and produce apoptosis through the involvement of caspases in zebrafish embryos. In this study, we investigated the developmental toxicity of cypermethrin using zebrafish embryos, which could be helpful in fully understanding the potential mechanisms of cypermethrin exposure during embryogenesis and also suggested that zebrafish could serve as an ideal model for studying developmental toxicity of environmental contaminants.