病区水龙头相关物表铜绿假单胞菌污染分析

目的 了解中山市中医院31个住院病区医生办公室水池相关物表污染情况,分析相关危险因素,为医院水源性感染防控措施提供科学依据。方法 按国家规范采集医院住院大楼31个病区医生办公室水池相关样本,包括水龙头相关物表、水池旁饮水机相关物表、水样本等三种类型共201份样本。记录每个采集部位特征,包括水龙头采样部位、有无安装起泡器、朝向、环境类型、龙头类型、手柄特征等信息。采用微生物法检测样本和进行铜绿假单胞菌的鉴定来掌握物表污染情况。结果 201份样本三种类型物表检出铜绿假单胞菌的阳性率有统计学意义(用Fisher精确独立性检验P <0. 001),其中水龙头相关物表铜绿假单胞菌检出的阳性率最高16. 216%。对水龙头相关物表进行单因素分析,显示水龙头不同采样部位的铜绿假单胞菌检出的阳性率有差异,结果有统计学意义(χ^(2)=4. 874,P <0. 050),水龙头体的污染风险最高。将龙头类型、手柄特征、朝向、科室类型、菌落数是否合格、龙头口无安装起泡器等因素作为自变量进行非条件Logistic回归分析,发现这些因素对铜绿假单胞菌检出的阳性率,无统计学意义(Fisher精确独立性检验P>0. 05)。但水龙头不同采样部位、龙头口有无安装起泡器两个自变量同时加入Logistic模型,拟合优度检验AIC值最低61. 696,显示没有安装起泡器的水龙头体容易检出铜绿假单胞菌。结论 病区医生办公室内水龙头污染严重,清洁易被忽视。制定规范的水源性相关感控措施,切断医院感染传播途径有必要。

医院Ⅰ类环境水龙头污染现况调查及风险评估

目的了解医院内Ⅰ类环境中水龙头及相关水槽的微生物污染现状.方法2023年3-4月对某三甲医院所有Ⅰ类环境科室中水龙头及其相关水槽进行物体表面采样,通过细菌培养的方法检测相应采样点微生物污染的现况,并收集相关信息筛选与污染相关的危险因素.结果该医院Ⅰ类环境水龙头设施细菌超标率为32.46%(74/228),检出率最高的细菌是铜绿假单胞菌(8.49%,9/106);另外检出3株耐碳青霉烯鲍氏不动杆菌;多因素Logistic回归分析的结果显示,房间洁净级别(OR=1.629,95%CI:1.091~2.434,P=0.017)、使用年限(OR=0.489,95%CI:0.262~0.911,P=0.024)对水龙头设施微生物污染的影响具有统计学意义.结论医院Ⅰ类环境水龙头污染严重,亟待制定专门针对Ⅰ类环境的清洁消毒措施,以防止相关医院内感染的发生.

Sorption and Fractionation of a Peat Derived Humic Acid by Kaolinite, Montmorillonite, and Goethite

Sorption of humic acid （HA） on mineral surfaces has a profound interest regarding the fate of hydrophobic organic contaminants （HOCs） and carbon sequestration in soils. The objective of our study is to determine the fractionation behavior of HA upon sorption on mineral surfaces with varying surface properties. HA was coated sequentially on kaolinite （1：1 clay）, montmorillonite （2：1 clay）, and goethite （iron oxide） for four times. The unadsorbed HA fractions were characterized by elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy （DRIFT）, and solid state 13C nuclear magnetic resonance spectroscopy （NMR）. The mineral-HA complexes were characterized by DRIFT. Polarity index [（N＋O）/C] revealed higher polarity of the unadsorbed HA fractions after coating on kaolinite, reflecting that relatively higher polarity fractions of HA remain unadsorbed. Sorption of aiiphatic alcohol fraction along with carbohydrate was prominent on kaolinite surface. DRIFT results of the unadsorbed HA fractions indicated more sorption of aiiphatic moieties on both kaolinite and montmorillonite. DRIFT results of the unadsorbed HA fractions after sorption on kaolinite and goethite showed the sorption of the proteinaceons fractions of HA. The HA fractions obtained after coating on goethite showed significant sorption of carboxylic moieties. The results mentioned above comply reasonably well with the DRIFT spectra of the minerai-HA complexes. ^13C NMR results showed higher sorption of anomeric C on kaolinite surface. Higher sorption of paraffinic fraction waS observed on montmorillonite. NMR data inferred the sorption of carboxylic moieties on goethite surface. Overall, this study showed that aliphatic moieties of HA preferentially sorbed on kaolinite and montmorillonite, while carboxylic functional groups play a significant role in sorption of HA on goethite. The sorbed fractions of HA may modify the mineral surface properties, and thus, the interaction with organic contaminants.

Isolation and Characterization of a Bensulfuron-Methyl-Degrading Strain L1 of Bacillus

The objectives of this study were to isolate a bensulfuron-methyl （BSM）-degrading strain of Bacillus spp. and to evaluate its effectiveness in remediation of a BSM-contaminated soil. A BSM-degrading bacterium, strain L1, was successfully isolated in this study. Strain L1 was identified as Bacillus megaterium based on its morphological, physiological, and biochemical properties, G＋C content, phylogenetie similarity of 16S rDNA, and fatty acid composition. Two experiments were used to examine BSM degradation by strain L1. When BSM was used as a sole carbon source in a mineral salt medium, the average degradation rate of BSM by strain L1 was 12.8%, which suggested that the strain was able to utilize BSM as a sole carbon and energy source. Supplement of yeast extract （200 mg L^-1） significantly （P ≤ 0.01） accelerated the degradation of BSM by strain L1. Ahnost complete degradation （97.7%） of BSM could be achieved in 84 h with addition of yeast extract. In addition, in a sterile soil with 50 mg L^-1 BSM, BSM degradation rate by strain L1 was 94.3% in 42 d, indicating the potential of using microbes for the remediation of BSM-contaminated soils in fields.

Electrodeposition and Surface Characterization of Sulfur on Polycrystalline Platinum from Sulfide Polluted Brine

This paper investigated the electrodeposition of sulfur on polycrystalline platinum from sulfide polluted brine. Anodic polarization, potentiostatic and electrochemical impedance spectroscopy （EIS） techniques were performed. The slope of Warburg straight line in Nyquiest plot of the EIS spectra performed at 0.0 V indicates diffusion control mechanism of the electrodeposition process. At 0.5 V the Rp （determined from EIS measurements） increased rapidly with time indicating more sulfur deposition and more passivation of platinum surface. Samples subjected to potentiostatic experiments at 0.4, 0.9 and 1.0 V were investigated under Scanning Electron Microscope （SEM）. SEM images reveal the deposition of sulfur on the sample surfaces. The degree of sulfur deposit coverage and its morphology depend on both the potential and time of deposition.

Distribution Pattern of Heavy Metals in the Surface Sediments of the Jiaozhou Bay

Grain size analysis and chemical analysis of heavy metals are made for 312 surface samples of the Jiaozhou Bay. Nineteen samples of the waste water taken from the sewage discharge outlets along the eastern coast of the bay are also analyzed for heavy metals. Results show that heavy metals are richer in the east and poorer in the west of the bay. Sedimentary dynamic studies reveal that the distribution of heavy metals in the surface sediments of the Jiaozhou Bay is under the control of hydrodynamics.

Grain-size related nitrogen distribution in southern Yellow Sea surface sediments

Forty-eight surface sediments of the southern Yellow Sea are separated into three grain-size frac- tions. Four forms of extractable nitrogen (nitrogen in ion-exchangeable form (Nie), nitrogen in weak-acid ex- tractable form (Nwa), nitrogen in strong-alkali extractable form (Nsa) and nitrogen in strong-oxidant form (Nso)) are obtained by the sequential extraction. The results show that the contents and the distributions of the extract- able nitrogen in the southern Yellow Sea surface sediments are closely related to sediment grain size. The distri- butions of Nie, Nso and total nitrogen (TN) present positive correlations with fine particles content, while Nwa and Nsa does not have such correlation. The net contents of all the forms of nitrogen increase with sediment grain size finer.

Distribution and pollution assessment of trace metals in seawater and sediment in Laizhou Bay

Selected trace metals （Pb, Cd, Cu, Hg） and arsenic in seawater and surface sediments of Laizhou Bay were determined, to evaluate their spatial distribution, pollution risk and potential ecological risk. Concentrations of the elements were 0.56-2.07, 0.14-0.38, 12.70-18.40, 0.014-0.094, and 1.13- 2.37 μg/L in the seawater and 8.94-32.2, 0.18-0.67, 4.51-30.5, 0.006-0.058, and 5.75-15.3 mg/kg in sediments for Pb, Cd, Cu, Hg and As, respectively. High concentrations of the trace metals and arsenic in seawater and surface sediments were generally observed near the fiver estuary. The pollution risk result of the elements showed that Cu was the prominent trace metal pollutant in seawater, followed by Hg, Pb, Cd and As. The metal complex pollution index in seawater was at a medium level. The most important trace metal pollutant in sediments was Cd, followed by As, Cu, Pb, and Hg. Our pollution assessment suggests that trace metal pollution in Laizhou Bay sediments was at a low level. The potential ecological risk was also low in surface sediment.

Assessment of Heavy Metal Pollution in Estuarine Surface Sediments of Tangxi River in Chaohu Lake Basin

A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor （EF） and geoaccumulation index （Igeo） as well as multivariate statistical analysis methods including Factor Analysis （FA） and Hierarchical Cluster Analysis （HCA） were applied for the assessment of heavy metal pollution in surface sediments. The results of EF values show that the pollution of copper （Cu） and cadmium （Cd） occurs in the estuarine sediments, and that zinc （Zn）, lead （Pb） and chrome （Cr） may originate from crustal materials or natural weathering process. The mean EF values of the five heavy metals are in the decreasing order： Cu〉Cd）Zn〉Pb〉Cr. Based on the lgeo of target heavy metals, the surface sediments collected from the study area can be approximately categorized as unpolluted with Zn, Pb and Cr, and moderately polluted with Cu and Cd. The degree of heavy metal pollution decreases in the order of Cu〉Cd〉Zn〉Pb〉Cr. Three groups of pollution factors are presented from FA： Zn-TOC, Cu-Cd and Cr-Pb, which respectively accounte for 27.22%, 25.20% and 21.05% of variance. By means of HCA, a total number of seven groups are distinguished from 30 sampling sites. Results indicate that Cu and Cd are the prior controlled pollutants in the estuarine sediments of the Tangxi River.

Distribution and Source of Main Contaminants in Surface Sediments of Tidal Flats in the Northern Shandong Province

Twenty-nine samples of surface sediments from tidal flats in the Northern Shandong Province were collected for grain size, heavy metal(Hg, Cu, Pb, Zn, Cd, and Cr), and oil pollution analyses. The geoaccumulation index(Igeo) and factor analysis were introduced to evaluate sediment quality and source of contaminants. The mean concentrations of Hg, Cu, Pb, Zn, Cd, Cr, and oil in the surface sediments in the study area are 0.033, 17.756, 19.121, 55.700, 0.291, 59.563, and 14.213 μg g-1, respectively. The heavy metal contamination in the old delta lobe is slightly higher than that in the abandoned delta lobe; however, the opposite was observed for oil pollution. The Igeo results revealed that the overall quality of the surface sediments in the study area is in good condition. The heavy metal pollution levels show a descending order: Cd> Hg> Cr> Cu> Zn> Pb, Cd being the main pollutant. The contamination level for in the study area is relatively lower than those for China's other tidal flats. Heavy metals are mainly derived from natural sources of rock weathering and erosion, partly influenced by industrial and agricultural discharge. However, oil pollution is mainly from runoff input, motorized fishing boat sewage, and oil exploitation.

A Method and a Surface Treatment Agent for Preventing Biofouling on Surfaces under Water

This paper presents an environm centally friendly method of inhibiting biofouling especially acorn barnacles on surfaces under water by using nicotine and selenium in the form of Se（0）, or such a substance which can be converted into them. Both of the substances are necessary to oxygen dependent organisms and will be used after conversion, but are toxic in high doses. By adding the substances to paint or other surface treatment agent which marine surfaces are treated with, organisms which are trying to establish themselves on the surfaces will be exposed to so high doses, the reactions which the settling is based on are disturbed. When the substances leak out into the seas, they will act as environment protectors, as they promote the development of organisms. Nicotine is transformed to nicotine amid which is the reactive part in NADH and one of the most important substances for the transference of hydrogen. Selenite is reduced to Se（0）, also involved in the transport chain of hydrogen to reducible oxygen. However, large quantities Se（0） may disturb the reactions of sulphur b＇./binding to it and impairing the formation of S-S-bridges.

Volume and Toxic Composition of Leachate from an Open Dump

In Mexico, hazardous and non-hazardous urban solid wastes are commonly disposed of in dumps. Inappropriate waste disposal makes solid waste disposal sites potential sources of pollution and health risks. The objective of the present study was to evaluate the impact of leachate from a dump on surface water systems. Physical, chemical, and bacteriological characteristics and the volume of leachate were measured. The site of study is located in Zinaprcuaro, Michoac^m, Mexico, and was chosen due to the water supplies were in line with the dump, thus conforming a system to test for movement of toxins. Leachate and water from three ponds located at different distances to the dump were sampled during three months of a year to measure physicochemical and bacteriological parameters, according to the standard methods of the American Public Health Association; the concentration of heavy metals was measured by atomic absorption spectrometry. Most characteristics exceed the maximum permissible limits established for the Mexican legislation regarding wastewater discharges and drinking water. Likewise, analysis of variance showed statistically significant differences between concentrations of pollutants in relation to the distance from the dump of sampled sites and with season of sampling, thus confirming the contamination of water by dump leachate.

Batch washing of saturated hydrocarbons and polycyclic aromatic hydrocarbons from crude oil contaminated soils using bio-surfactant

Desorption of total saturated fractions(i.e. SAT, defined for this study as the summation of the concentrations of the saturated hydrocarbon from n-C10 to n-C26) and polycyclic aromatic fractions(i.e. PAH, defined as the summation of the concentrations of all polycyclic aromatic fractions including the 16 EPA priority PAH) in two types of soils subjected to the changes of p H and salinity and different bio-surfactant concentrations were investigated. In general, compared with the experiments without bio-surfactant addition, adding rhamnolipid to crude oil-water systems at concentrations above its critical micelle concentration(CMC) values benefits SAT and PAH desorption. The results indicate that the change of p H could have distinct effects on rhamnolipid performance concerning its own micelle structure and soil properties. For loam soil, the adsorption of non-aqueous phase liquid(NAPL) and rhamnolipid would be the principle limiting factors during the NAPL removal procedure. For sand soil, less amount of rhamnolipid is adsorbed onto soil. Thus, with the increase of salinity, the solubilization and desorption of rhamnolipid solution are more significant. In summary, the p H and salt sensitivity of the bio-surfactant will vary according to the specific structure of the surfactant characteristics and soil properties.

Climate Change and Environmental Impact Caused by Anthropogenic

For the last two decades the world has undergone a population explosion which has been accompanied by a speeding up of urbanization and land use for industrial and agricultural products. These involve a vast increase in the discharge of pollutants into very different receiving water bodies, and have had adverse effects on the various components of the environment. For a long time, human has concerned a little of the natural environment. It is obvious that this variation in surface temperature of the earth increases the level of sea due to snowmelt. So climate change is manifested by many phenomena： floods, droughts, fires, tornadoes, cyclones, earthquakes, volcanic eruptions, diseases etc.. The statement today is dramatic. Entire regions were devastated and many rivers and lakes have become polluted around the world. Pollution has it nature which is hard to be absorbed. Where did the different pollutants come from？ What are the risks to the aquatic environment？ To prevent and combat the general decline of these ecosystems, it is important to distinguish and determine the effects of different sources of pollution and any changes that may suffer the physical environment. The climate depends primarily on changes in earth orbit parameters, which affect the solar radiation received by the earth surface. Therefore, human participates strongly to these changes, for example, pollution is the main reason to argue the greenhouse effect, an increase of anthropogenic carbon dioxide （CO2） into the atmosphere, which promotes global warming to the planet. These modifications are already applied in order to ensure durable development in water resources by controlling discharges into streams to preserve water resources for future generations and to ensure reconciliation between man-climate and environment.

Heavy Metal Pollution of Sediments from Coastal Areas： Assessment of the Environmental Impact of Polluted Surface Sediments from the Bay of Luanda, Angola

Luanda bay has been acting as a sink for the untreated municipal and industrial effluents from a part of the city. Sediment samples were analyzed for their total organic carbon contents and pseudo-total concentrations ofFe, Mn, Hg, Cd, Pb, Cu, Zn, Ni and Cr The highest concentrations of organic carbon and Hg, Cd, Pb, Cu and Zn were found near the sewerage discharge outlets, exceeding in these points the lowest Sediment Quality Guidelines for the occurrence of adverse biological effects. A further study, based on the latest version of the BCR sequential extraction procedure, was undertaken in order to assess the physical/chemical binding and bioavailability ofFe, Mn, Cd, Pb, Cu and Zn in these sediments. The toxic metals Cd, Zn, Pb and Cu pose a potential environmental risk, because they were extracted from the sediment labile fractions in concentrations that exceeded the corresponding ERL （Effects Range Low） values, entering the range within which adverse biological effects occur. The non-residual fractions of metals ranged from 91 to 100% for Cd, 89 to 94% for Zn, 67 to 100% for Pb, 71 to 82% for Cu, 30 to 77% for Mn and 39 to 48% for Fe. Measures to be taken for the disposal of the polluted dredged sediments are shown in this work.

Research on solubilization used for micellar enhanced ultrafiltration

Micellar enhanced ultrafiltration （MEUF） is a new effective treatment technology for the filtration removal of organic pollutants through solubilization. The present paper is aimed to study the solubilization of organic compounds such as chlorobenzene （CB）, pyrene and phenol by anionic, cationic and mixed anionic-nonionic surfactants such as sodium dodecyl sulfate （SDS）, cetyltrimethylammonium bromide （CTMAB） and Tween-80 （TW80） and the mixed SDS-TW80 with a batch equilibrium method. This study enables us to supply deeper investigation for MEUF. The results showed that solubilization capacity was not obvious below the critical micellar concentration （CMC）. The apparent solubilities of organic compounds were linearly related to surfactant concentrations over their CMCs. Solubilization capacity by single surfactants follow the order of TW80 〉 CTMAB 〉 SDS. The results also proved that the solubilization of the organic contaminants by the mixed surfactants can significantly be enhanced compared with the single anionic surfactant SDS. Whereas the CMC can be decreased, the solubility can be increased as long as the mass ratio of nonionic surfactant increases. The solubility enhancement efficiency of the different organic compounds follow the order of phenol 〉 CB 〉 pyrene. In addition, the solubilization ratio appears to be positively relative to the intrinsic water solubility of the organic contaminants and negatively correlates to octanol-water coefficients （Kow） of organic compounds and the hydrophile-lypophile balance values （HLB） of the surfactants.

Spatial Distribution of Heavy Metals in Surface Sediments of the Sakumo Lagoon, Ghana

The aim of this study was to determine the possible build up of heavy metals （Pb, Cu, Fe, Mn and Zn） in the Sakumo lagoon, a Ramsar site situated 3 km west of Tema, an industrial town in Ghana. To achieve this, surface sediments were collected from three sections designated as south, centre and north of the lagoon. Sampling was done for a period of six months （September 2007 to February 2008） and concentrations of the heavy metals （Pb, Cu, Mn, Fe and Zn） in the sediments were determined using the atomic absorption spectrophotometer. The results were compared with the mean concentrations of these metals from a study carried out on the same lagoon in 2003. It was observed that concentrations of these heavy metals in the sediments showed a significant increase over the 2003 levels except for lead where a decrease was observed. The metals also showed spatially large variation from south to north. The spatial variations in concentrations indicate the different absorption capacities of the sediments in the lagoon, a phenomenon which shows that recent anthropogenic heavy metal pollution had occurred. Statistical analysis also showed significant correlation between Pb and Cu （0.968） at 0.01 confidence level and between Cu and Zn （0.869） at 0.05 confidence level.

Geochemical Assessment of Heavy Metals in Surface Sediments： A Case Study of the Tema Port, Ghana

Ten trace and heavy metals （Fe, Mn, Ni, Zn, Cu, Cd, As, Co, Cr and V） were analysed in sediments collected from nine stations at the Tema Port of Ghana, during the dry and wet seasons. Analysis of samples was done using INAA （instrumental neutron activation analysis） for Mn, V, Cu, As and Cd, and AAS （atomic absorption spectrophotometry） for Fe, Cr, Zn, Ni and Co. The concentrations of metals in sediments followed the orders Fe 〉 V〉 Mn 〉 Cd 〉 Ni 〉 Zn 〉 Cu 〉As, for the dry season and Fe 〉 V 〉 Ni 〉 Cu 〉 Zn 〉 Mn 〉 Cd 〉As, for the wet season. Concentrations of Co and Cr were below detection limit, whiles Cu, Cd and Ni were found to be above the TELs （threshold effect levels） of NOAA＇s （National Oceanic and Atmospheric Administration＇s） SQuiRTs （screening quick reference tables） at most sites. Estimated enrichment factors for individual metals showed very high contamination of the port＇s sediments, with Cd occurring at all sites, and Cu, As, V and Ni occurring at some sites for both dry and wet seasons. Although sediments from the Tema Port were highly enriched with Cd, Cu, Ni and V above natural background levels, the overall PLI （pollution load index） per sampling station considering background values of the analysed elements indicated that metal pollution in the port＇s sediment is below 1, indicating relatively unpolluted sediment.

Insights into the selective catalytic reduction of NO by NH_3 over Mn_3O_4(110):a DFT study coupled with microkinetic analysis

Nitric oxide(NO_x), as one of the main pollutants, can contribute to a series of environmental problems, and to date the selective catalytic reduction(SCR) of NO_x with NH_3 in the presence of excess of O_2 over the catalysts has served as one of the most effective methods, in which Mn-based catalysts have been widely studied owing to their excellent low-temperature activity toward NH3-SCR. However, the related structure-activity relation was not satisfactorily explored at the atomic level. By virtue of DFT+U calculations together with microkinetic analysis, we systemically investigate the selective catalytic reduction process of NO with NH_3 over Mn_3 O_4(110), and identify the crucial thermodynamic and kinetic factors that limit the catalytic activity and selectivity.It is found that NH3 prefers to adsorb on the Lewis acid site and then dehydrogenates into NH_2~* assisted by either the two-or three-fold lattice oxygen; NH_2~* would then react with the gaseous NO to form an important intermediate NH_2 NO that prefers to convert into N_2 O rather than N_2 after the sequential dehydrogenation, while the residual H atoms interact with O_2 and left the surface in the form of H_2 O. The rate-determining step is proposed to be the coupling reaction between NH_2~* and gaseous NO.Regarding the complex surface structure of Mn_3 O_4(110),the main active sites are quantitatively revealed to be O_(3 c) and Mn_(4 c).

Opinion on the recent development of environmentally friendly marine anti-fouling coating

Marine biofouling is a global problem that is detrimental to both moving ships and static underwater devices.Marine microorganisms tend to attach to any unprotected surface and grow into biofilm,which can be hardly removed even under high shear flow condition[1].With the long-term accumulation of marine organisms,ships suffer significantly from the increase on the net weight as well as the drag when cruising.Increased drag causes fuel power penalties of up to86%at cruising speed;it is notable even a very thin layer