聚四氟乙烯高压密封罐消解样品测定五氧化二钒

利用聚四氟乙烯高压密封罐消解矿石样品测定五氧化二钒,具有操作手续相对简便、轻松、快捷等优点,与传统的硫酸－磷酸混合酸消解或采用碱熔融前处理法比较,相对误差小于１．６％,样品的添加标准回收率为９２．９％～１０３．５％。     

Distribution of antibiotic-resistant bacteria in chicken manure and manure-fertilized vegetables

Veterinary manure is an important pollution reservoir of antibiotics and antibiotic-resistant bacteria (ARB). However, little is known of the distribution of ARB in plant endophytic bacteria and the number/types of ARB in chicken manure. In this study, 454-pyrosequencing was used to investigate the distribution and composition of ARBs in chicken manure and fertilized vegetables. The prevalence of ARB in the samples of the chicken manure compost recovered from farms on which amoxicillin, kanamycin, gentamicin, and cephalexin were used was 20.91–65.9 % for ARBs and 8.24–20.63 % simultaneously resistant to two or more antibiotics (multiple antibiotic resistant bacteria (MARB)). Antibiotic-resistant endophytic bacteria were widely detected in celery, pakchoi, and cucumber with the highest rate of resistance to cephalexin. The pyrosequencing indicated that the chicken manure dominantly harbored Firmicutes, Bacteroidetes, Synergistetes, and Proteobacteria and that Bacteroidetes was significantly enhanced in farms utilizing antibiotics. In the total cultivable colonies, 62.58–89.43 % ARBs and 95.29 % MARB were clustered in Bacteroidetes with the dominant species (Myroides ordoratimimus and Spningobacterium spp., respectively) related to human clinical opportunistic pathogens.     

水中安替比林的紫外光降解研究

以波长为254 nm的紫外杀菌灯为光源,研究了水溶液中消炎镇痛药物安替比林（PZ）的光降解行为;考察了初始pH值及水中其他物质对PZ光降解的影响,探讨了PZ光解机制,并分析其降解产物及光解途径。结果表明,安替比林的光降解遵循拟一级反应动力学规律,pH值变化对光解速率基本没有影响。安替比林直接光降解占主导作用,活性氧类物种（ROS）对安替比林间接光解基本没有贡献。腐殖酸对安替比林光降解有抑制作用,而NO^-₃,HCO^-₃,Cl^-对安替比林光降解没有明显作用。GC-MS分析表明安替比林在紫外辐射下生成甲酰胺,乙酰胺,2-羟基吲哚-3-酮,2,4（1氢,3甲基）-喹唑啉二酮,1-甲基-2-羟基苯并咪唑,2-羟基苯并恶唑等一系列具有安替比林母体苯环结构的化合物,表明安替比林侧链上N—N键断裂导致其最终降解。     

海洋环境中纳米金属的生物吸收及生物效应

当前随着纳米科技的发展,纳米材料,特别是纳米金属,因其独特的物化性质,在各行各业中的使用量呈指数增长,致使其在大气、水域、土壤环境中的安全性问题引起公众关注。尤其是在受到人类活动密切影响的近岸海洋环境中,纳米金属的潜在生态效应成为当前国内外研究的热点之一。本文重点综述了由于海洋环境的理化因子以及纳米金属独特的物化性质导致的纳米金属的环境行为,海洋生物对纳米金属的吸收,以及纳米金属的生物效应和可能的致毒机制,旨在为评估海洋环境中纳米金属的潜在生态危害,完善纳米材料的监管机制及保障纳米科技的可持续发展提供思路。     

IFC化肥增效剂对盆栽小白菜的生物效应和环境效应

IFC化肥增效剂在盆栽小白菜上的应用试验表明:与单独施用碳铵处理相比,施用碳铵 IFC化肥增效剂可使小白菜鲜重增加8.97%(P＜0.01),干重增加3.45%(P＜0.05),吸氮总量增加8.70%(P＜0.01),NO-3-N含量降低30.10%(P＜0.01),但含氮率无明显变化.IFC在小白菜上的应用效果好于常用氮肥增效剂双氰胺.适量施用IFC化肥增效剂使土壤氨化强度略有增加,能在一定程度上抑制土壤反硝化作用,但对土壤微生物生物量未产生明显影响.     

农药废水中有机硫、磷污染物湿式空气氧化反应的研究

以o,o-二甲氧基或o,o-二乙氧基硫代磷酰氯废水为典型废水,在180—230℃,氧气压力为0.7—1.5MPa的反应条件下,在2L的不锈钢高压釜中,研究了农药废水中有机硫磷化合物在湿式空气氧化过程中的降解机制。实验结果表明,有机硫磷化合物分子中的有机硫通过氧化反应降解为硫酸,有机磷通过水解反应降解为磷酸。有机硫氧化生成的硫酸是废水湿式空气氧化过程中酸度增加的主要来源,酸性条件比碱性条件更利于有机硫磷化合物的湿式空气氧化降解。     

Relationship between groundwater cadmium and vicinity resident urine cadmium levels in the non-ferrous metal smelting area,China

● This study systematically examined the relationship between groundwater Cd and UCL. ● The study covered 211 UCL and sociological characteristic from nine groundwater samples. ● We found a significant positive correlation between groundwater Cd and UCL. ● Smoking status and education level also significantly affected UCL. Cadmium (Cd) has received widespread attention owing to its persistent toxicity and non-degradability. Cd in the human body is mainly absorbed from the external environment and is usually assessed using urinary Cd. Hunan Province is the heartland of the Chinese non-ferrous mining area, where several serious Cd pollution events have occurred, including high levels of Cd in the urine of residents. However, the environmental factors influencing high urinary Cd levels (UCLs) in nearby residents remain unclear. Therefore, 211 nearby residents’ UCLs and the corresponding sociological characteristics from nine groundwater samples in this area were analyzed using statistical analysis models. Groundwater Cd concentration ranged from 0.02 to 1.15 μg/L, aligning with class III of the national standard; the range of UCL of nearby residents was 0.37–36.60 μg/L, exceeding the national guideline of 0–2.5 μg/L. Groundwater Cd levels were positively correlated with the UCL (P < 0.001, correlation coefficient 95 % CI = 9.68, R² = 0.06). In addition, sociological characteristics, such as smoking status and education level, also affect UCL. All results indicate that local governments should strengthen the prevention and abatement of groundwater Cd pollution. This study is the first to systematically evaluate the relationship between groundwater Cd and UCL using internal and external environmental exposure data. These findings provide essential bases for relevant departments to reduce Cd exposure in regions where the heavy metal industry is globally prevalent.     

Rapid degradation of butachlor in wheat rhizosphere soil

The degradative characteristics of butachlor in non-rhizosphere, wheat rhizosphere, and inoculated rhizosphere soils were measured. The rate constants for the degradation of butachlor in non-rhizosphere, rhizosphere, and inoculated rhizosphere soils were measured to be 0.0385, 0.0902, 0.1091 at 1 mg/kg, 0.0348, 0.0629, 0.2355 at 10 mg/kg, and 0.0299, 0.0386, 0.0642 at 100 mg/kg, respectively. The corresponding half-lives for butachlor in the soils were calculated to be 18.0, 7.7, 6.3 days at 1 mg/kg, 19.9, 11.0, 2.9 days at 10 mg/kg, and 23.2, 18.0, 10.8 days at 100 mg/kg, respectively. The experimental results show that the degradation of butachlor can be enhanced greatly in wheat rhizosphere, and especially in the rhizosphere inoculated with the bacterial community designated HD which is capable of degrading butachlor. It could be concluded that rhizosphere soil inoculated with microorganisms-degrading target herbicides is a useful pathway to achieve rapid degradation of the herbicides in soil.     

铁镍改性膨润土对废水中有机污染物的吸附性能研究

以钠基膨润土为原料,制备了铁镍无机改性土和铁镍有机复合改性土,并应用于造纸废水的处理,探讨了改性土用量、废水pH值、搅拌时间等因素对COD去除率的影响,通过正交实验对实验条件进行了优化.结果表明:铁镍有机复合改性土和铁镍元机改性土对废水的处理效果明显好于原土;膨润土的用量、废水的pH对COD的去除率影响较大;对于铁镍无机改性土,吸附剂用量为12g/L,溶液pH=2,吸附时间为10 min时,对废水中COD的去除率为54.06%;对于铁镍有机复合改性土,吸附剂用量为14g/L,溶液pH=3,吸附时间为20 min时,对废水中COD的去除率为70.10%.     

Mn2O3/γ-Al2O3在超临界水氧化中催化活性的研究

采用浸渍法制备了Mn2O3/γ-Al2O3催化剂,在超临界水中催化氧化降解1,5-萘二磺酸,探索了催化剂Mn2O3活性组分负载量、催化剂空速和反应溶液pH对Mn2O3/γ-Al2O3催化剂活性的影响。结果表明：Mn2O3/γ-Al2O3的催化活性在一定范围内随Mn2O3活性组分负载量的增加而提高;在一定范围内,Mn2O3/γ-Al2O3空速越小,模拟废水的COD去除率越高;Mn2O3/γ-Al2O3催化活性在反应溶液呈酸性情况下比碱性时高。