Contamination of organochlorine pesticides in water and sediments from a waterbird-inhabited lake,East Central China

Seventeen organochlorine pesticides (OCPs) were investigated in the water and sediments from a waterbird-inhabited lake (Yangchaihu Lake) to evaluate their current pollution levels and potential risks. The concentrations of total OCPs in water and sediments were 10.12–59.75 ng/l and 4.25–27.35 ng/g dry weight, respectively. Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the most abundant OCPs, while HCB and cyclodiene pesticides were detected with low levels. Levels of ∑OCPs (sum of 17 OCPs) at sites highly influenced by waterbirds were significantly higher than the sites with no significant waterbird populations (one-way ANOVA, P?相似文献   

Distribution and ecological risk assessment of organochlorine pesticides in surface sediments from the East Lake,China

Organochlorine pesticides (OCPs) are ubiquitous pollutants, and their presence in urban lakes is a concern for human and ecological health. Surface sediments in the East Lake, China, were collected in winter 2012 and summer 2013 to investigate concentrations, distribution patterns, possible sources, and potential ecological risks of OCPs in this area. The total concentrations of 14 OCPs ranged from 6.3 to 400 ng g^?1 dry weight (dw) with an average concentration of 79 ng g^?1 dw. The mean values of hexachlorocyclohexanes (HCHs) (α-, β-, γ-, and δ-HCH) and dichlorodiphenyltrichloroethanes (DDTs) (p,p’-DDE, p,p’-DDD, and p,p’-DDT) were 36 and 7.6 ng g^?1 dw, accounting for 45 and 10 % of the total OCPs, respectively. The concentrations of OCPs in sediment samples collected in winter were significantly higher than those in summer, especially the HCHs, of which in winter were two times greater than summer. Composition analyses indicated that DDTs and endosulfan were mainly from historical contribution. Historical use of technical HCH and new input of lindane were probably the source of HCHs in the East Lake. Most sampling sites of HCHs and DDTs were found to have the potential ecological risk based on levels specified in the sediment quality standards.     

Measurements of the streaming potential of clay soils from tropical and subtropical regions using self-made apparatus

The streaming potential has been wildly used in charged parallel plates, capillaries, and porous media. However, there have been few studies involving the ζ potential of clay soils based on streaming potential measurements. A laboratory apparatus was developed in this study to measure the streaming potential (ΔE) of bulk clay soils’ coupling coefficient (C) and cell resistance (R) of saturated granular soil samples. Excellent linearity of ΔE versus liquid pressure (ΔP) ensured the validity of measurements. The obtained parameters of C and R can be used to calculate the ζ potential of bulk soils. The results indicated that the ζ potentials measured by streaming potential method were significantly correlated with the ζ potentials of soil colloids determined by electrophoresis (r ²?=?0.960**). Therefore, the streaming potential method can be used to study the ζ potentials of bulk clay soils. The absolute values of the ζ potentials of four soils followed the order: Ultisol from Jiangxi?>?Ultisol from Anhui?>?Oxisol from Guangdong?>?Oxisol from Hainan, and this was consistent with the cation exchange capacities of these soils. The type and concentration of electrolytes affected soil ζ potentials. The ζ potential became less negative with increased electrolyte concentration. The ζ potentials were more negative in monovalent than in divalent cationic electrolyte solutions because more divalent cations were distributed in the shear plane of the diffuse layer as counter-cations on the soil surfaces than monovalent cations at the same electrolyte concentration.     

Degradation of aqueous Rhodamine B by plasma generated along the water surface and its enhancement using nanocrystalline Fe-, Mn-, and Ce-doped TiO2 films

The degradation of aqueous Rhodamine B (RhB) was examined using a dual-channel spark switch module designed to regulate the steepness of pulsed high voltage with microsecond rise time. Depending on the energy per pulse, a spark along the water surface (SPWS) or streamer along the water surface (STWS) was formed. STWS was found to have a better degradation effect and energy efficiency toward RhB than SPWS at the same power; however, addition of H₂O₂ amounts resulted in increased degradation, the effect being more pronounced using SPWS. The initial concentration of RhB also appeared to influence the rate constant of the degradation reaction. Furthermore, TiO₂ films doped with Fe, Mn, and Ce were found to enhance the degradation performance of plasma. A possible reaction mechanism of plasma formation along the water surface was concluded by determination of the main inorganic products in the liquid and gas phases.     

发酵类抗生素废水处理工艺及运行效果

介绍了内蒙古某抗生素废水处理厂的处理工艺流程、处理单元类型及其详细设计参数,通过对该污水处理厂半年内运行效果的调研,分析评价该污水处理系统的处理效果及出水指标;该水厂工艺流程对COD、TOC、氨氮、总氮、总磷、BOD和急性毒性的平均去除率分别为96.52%、95.83%、50.24%、55.20%、62.05%、98.52%和99.14%,COD、氨氮、总氮、总磷出水水质分别为477、438、556.7和7.69 mg/L,达到排放到城区下水道要求,园区内所有废水汇集到园区污水处理厂进行集中深度处理达标后排放水体。通过对该水厂工艺的介绍和水质分析,为我国抗生素生产企业面临的废水处理工艺类型选择及工程改造升级提供一定参考。     

二氧化钛脱除高温烟气中的氯化氢

HCl是城市垃圾焚烧产生的主要气体污染物之一。将一种新型脱氯剂TiO2引入到垃圾焚烧系统中,并与其他脱氯剂的性能进行比较。研究了不同脱氯剂使用量、不同反应温度和不同HCl气体浓度对TiO2、CaO和CaTiO3脱氯效果的影响。结果显示,TiO2能在高温(800~1 000℃)、高HCl浓度(1 303.6~1 629.5 mg/m3)下获得较好的脱氯效果。与传统的脱氯剂CaO相比,TiO2更适合于高温烟气脱氯,其在1 000℃时的氯容(36.3 mg HCl/g TiO2)几乎是相同情况下的CaO氯容(9.3 mg HCl/g CaO)的4倍。而CaTiO3的脱氯效果不但受到自身分解效率的影响,还受到TiO2和CaO脱氯效果的影响,其脱氯效果较差。     

Potential toxicity of amphenicol antibiotic: binding of chloramphenicol to human serum albumin

Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet–visible (UV–Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP–HSA complex, and the binding constant was determined to be 3.196?×?10⁴ L mol^?1 at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage.     

Concentration and health risk evaluation of heavy metals in market-sold vegetables and fishes based on questionnaires in Beijing,China

Concentrations of heavy metals (As, Cd, Pb, Cu, Ni, Fe, Mn, and Zn) in market vegetables and fishes in Beijing, China, are investigated, and their health risk to local consumers is evaluated by calculating the target hazard quotient (THQ). The heavy metal concentrations in vegetables and fishes ranged from not detectable (ND) to 0.21 mg/kg fresh weight (f.w.) (As), ND to 0.10 mg/kg f.w. (Cd), and n.d to 0.57 mg/kg f.w. (Pb), with average concentrations of 0.17, 0.04, and 0.24 mg/kg f.w., respectively. The measured concentrations of As, Cd, Pb, Cu, Ni, Fe, Mn, and Zn are generally lower than the safety limits given by the Chinese regulation safety and quality standards of agriculture products (GB2762-2012). As, Cd, and Pb contaminations are found in vegetables and fishes. The exceeding standard rates are 19 % for As, 3 % for Cd, and 25 % for Pb. Pb contaminations are found quite focused on the fish samples from traditional agri-product markets. The paper further analyzed the health risk of heavy metals in vegetables and fishes respectively from supermarkets and traditional agri-product markets; the results showed that the fishes of traditional agri-product markets have higher health risk, while the supermarkets have vegetables of higher heavy metal risk, and the supervision should be strengthened in the fish supply channels in traditional agri-product markets.     

煅烧的水滑石同时去除水体中砷和氟

为探讨水滑石类材料对水体中氟、砷离子的同时去除效果,采用共沉淀法合成(Mg∶Al=2∶1)纳米类水滑石(LDHs),用傅立叶转换红外光谱、电子扫描透射电镜、X射线晶体衍射等手段对合成的材料进行了表征,并研究纳米材料在不同初始浓度、pH、吸附时间、阴离子干扰条件下其同时除砷氟性能。结果表明,煅烧后的水滑石(LDOs)对砷最大吸附量为51.02 mg/g,对氟最大吸附量为36.63 mg/g。吸附动力学实验表明,煅烧水滑石对砷的吸附在前6 h内基本完成,对氟的吸附在前10 h内基本完成。砷氟共存溶液保持pH=4~10及pH=6~8时,水滑石分别对砷、氟保持良好的吸附效率。对比不同阴离子对水滑石共除砷氟效率的影响,水滑石除砷速率受到阴离子影响力大小为:HPO2-4CO2-3NO-3Cl-SO2-4;水滑石除氟速率受到阴离子影响力大小为:CO2-3HPO2-4SO2-4Cl-NO-3。材料再生循环利用4次后,对砷和氟的吸附效率均能达到90%以上。实验结果表明,所合成的水滑石是一种优秀的能共除砷氟的吸附剂。     

Reduction of Fusarium rot and maintenance of fruit quality in melon using eco-friendly hot water treatment

Significant losses in harvested fruit can be directly attributable to decay fungi and quality deterioration. Hot water treatment (HWT) has been demonstrated to be an effective and economic environment-friendly approach for managing postharvest decay and maintaining fruit quality. In this study, the effects of HWT (45 °C for 10, 15, 20, and 25 min) on in vitro growth of Fusarium oxysporum, in vivo Fusarium rot, and natural decay of melon were investigated. HWT inhibited spore germination and germ tube elongation of F. oxysporum. Protein impairment and ATP consumption triggered by HWT contributed to the inhibitory effect. Results of in vivo studies showed that HWT effectively controlled Fusarium rot and natural decay of melon. Correspondingly, HWT induced a significant increase in content of total phenolic compounds and lignin of melon. These findings indicate that the effects of HWT on Fusarium rot may be associated with the direct fungal inhibition and the elicitation of defense responses in fruit. Importantly, HWT used in this study had beneficial effects on fruit quality as well. HWT may represent an effective non-chemical approach for management of postharvest Fusarium rot.