焦化废水中细菌质粒的研究

细菌质粒中常带有一些可编码降解特殊有毒物质酶的基因,为了研究质粒对有毒物质CN^-的降解的意义,主要调查了焦化废水中好氧异养菌的质粒分布特点。从山西省焦化企业公司生化站、太原煤气公司焦化厂生化站中筛选出53株细菌,利用琼脂糖凝胶电泳法,采用GDS-8000型凝胶电泳分析仪进行拍照,同时测定各菌株降氰、降酚能力,CN^-采用异烟酸-毗唑啉酮法,酚采用4-氨基安替比林法测定。结果表明,质粒的存在与降氰力有一定的关系,但对降酚力的影响差异不显著。同时,通过对其中11^*号菌株进行了质粒转化和消除实验,证明质粒稳定,不可用十二烷基磺酸钠(SDS)消除掉,用E．cbli DHI作受体菌,用11^#菌株作供体菌。作转化实验,但由于种种原因,没有筛洗到转化子。     

Assuring the quality of data in the pesticide residue laboratory

Abstract

The importance of quality control procedures to the collection of pesticide residue data is discussed. The equipment requirements of an adequate, safe pesticide residue laboratory are presented. Equipment maintenance, personnel training, and preservation of samples is also reviewed. Appropriate objectives for an intra‐laboratory quality control program are outlined.     

An alternative for the nitrobenzylpyridine test for the description of the toxicity of alkylating agents

When correlating the biologic activity of alkylating agents with physicochemical parameters, the reaction rate constant of the reaction with 4-(p-nitrobenzyl) pyridine (NBP) is often used as a measure of the compounds chemical reactivity. Since the use of NBP suffers some drawbacks from an experimental point of view, it was decided to develop an alternative test method, using thiourea as a standard nucleophile.Reactivities obtained with both methods for six halogenated alkylating agents are compared, and the usefulness of the new experimental method is discussed.     

Acid rain in the tropical forests of the Ivory Coast

This paper presents the first results concerning the acidity of the precipitation collected over a period of 1 year (February 1983–March 1984) in an undisturbed area of tropical forest in the Ivory Coast. A large proportion of the precipitation is acid, 77% bas a pH below 5.6. The average acidity is 5.0, with a temporal evolution tending towards a basic pH during the dry season, characteristic of the influence of the Sahelian terrigenous dust source and tending towards an acid pH of about 4.2 at the beginning of each humid period. This result, new for an African tropical forest, confirms the observations made in the Amazonian forests or in those of Northern Australia. An extensive research program on the acidity in the equatorial areas was started in the forests of the Ivory Coast and Congo in order to confirm this preliminary study.     

The Application of the Karl Fischer Oven for the Determination of Water in Consumer Products

Abstract

The direct Karl Fischer (KF) titration method has known interferences for measuring water content. In addition, in analyzing some paints, KF can fail to produce an accurate analysis. The California Air Resources Board (GARB) staff has developed a KF procedure that can be used to determine the water content of consumer products. The procedure uses an oven accessory to the titration system, and is based on a distillation method developed by the California Polytechnical University at San Luis Obispo (Cal Poly). Samples are diluted in l-methoxy-2-propanol (MPA), and an aliquot is injected into an enclosed oven system, where the MPA/water azeotrope is swept directly into the KF titration vessel. The technique is accurate and precise and, thus far, proves to be a fast and reliable method for analysis.     

Variation in diet composition: a hazard to the reliability of the LD50-test

The severity of toxic effects on nearly fully-grown birds from an organophosphorus insecticide (isofenphos) was shown to be affected by the tested birds' previous diet as juveniles. Subadult grey partridges (Perdix perdix), with an insect-poor diet as juveniles, were severely affected by the insecticide, whereas birds fed an insect-rich diet as juveniles showed no signs of poisoning after feeding on isofenphos-treated seeds.     

Adaptive management of the Great Barrier Reef and the Grand Canyon world heritage areas

Conventional perceptions of the interactions between people and their environment are rapidly transforming. Old paradigms that view humans as separate from nature, natural resources as inexhaustible or endlessly substitutable, and the world as stable, predictable, and in balance are no longer tenable. New conceptual frameworks are rapidly emerging based on an adaptive approach that focuses on learning and flexible management in a dynamic social-ecological landscape. Using two iconic World Heritage Areas as case studies (the Great Barrier Reef and the Grand Canyon) we outline how an improved integration of the scientific and social aspects of natural resource management can guide the evolution of multiscale systems of governance that confront and cope with uncertainty, risk, and change in an increasingly human-dominated world.     

环境监测实验室内质量控制体系的设想

环境监测实验室质量控制足环境监测质量保汪的蘑要组成部分。山于实验室内质量控制工作量大，质控工作往往流于形式。因此，有必要建立一套完整又便捷的实验室内质量控制体系，在质控质量上发挥重要作用。对体系建立前提条件和体系建立的，思路进行了阐述。对体系设计基础——计算机网络技术的运用。实验室内质量评价高效、便捷的数字化应用平台的建口进行了设想。     

The Variability of Dustfall Analysis Due to the Container and the Collecting Fluid

As part of their air pollution control program, many communities monitor the coarse dust content of the atmosphere by simply exposing an open vessel to the atmosphere for an extended period of time. The material collected and retained by a fluid layer is then weighed and chemically analyzed. In this study a statistical approach was used to separate the real and significant effects of different container-fluid combinations on both the magnitude of dustfall and its composition.     

A motley of possible therapies of the COVID-19: reminiscing the origin of the pandemic

Environmental Science and Pollution Research - The 2019 outbreak of corona virus disease began from Wuhan (China), transforming into a leading pandemic, posing an immense threat to the global...     

An Operational Assessment of the Application of the Relative Reduction Factors in the Demonstration of Attainment of the 8-Hr Ozone National Ambient Air Quality Standard

Abstract

The U.S. Environmental Protection Agency in 1997 revised the 1-hr ozone (O₃) National Ambient Air Quality Standard (NAAQS) to one based on an 8-hr average, resulting in potential nonattainment status for substantial portions of the eastern United States. The regulatory process provides for the development of a state implementation plan that includes a demonstration that the projected future O₃ concentrations will be at or below the NAAQS based on photochemical modeling and analytical techniques.

In this study, four photochemical modeling systems, based on two photochemical models, Community Model for Air Quality and the Comprehensive Air Quality Model with extensions, and two emissions processing models, Sparse Matrix Optimization Kernel for Emissions and Emissions Modeling System, were applied to the eastern United States, with emphasis on the northeastern Ozone Transport Region in terms of their response to oxides of nitrogen and volatile organic carbon-focused controls on the estimated design values. With the 8-hr O₃ NAAQS set as a bright-line test, it was found that a given area could be termed as being in or out of attainment of the NAAQS depending upon the modeling system. This suggests the need to provide an estimate of model-to-model uncertainty in the relative reduction factor (RRF) for a better understanding of the uncertainty in projecting the status of an area's attainment. Results indicate that the model-to-model differences considered in this study introduce an uncertainty of the future estimated design value of ～3–5 ppb.     

Minimization of the environmental impact in the unhairing of bovine hides

This study tests an alternative method to the traditional unhairing method used during the process of tanning the hides. The new method is based on the substitution of sodium sulfide by hydrogen peroxide as an unhairing agent in both hair recovery and recirculation of the floats employed in the process. The properties of the hides obtained using the two methods have been compared and the results indicate that those hides have similar physical, chemical, and organoleptic properties. However, the differences existing from an environmental point of view are significant. These include reductions of water consumption (approx 70%), chemical oxygen demand (approx 35%), toxicity (98%) and total kjendhal nitrogen (50%). Also, the risk associated with the production of hydrogen sulfide is eliminated, which implies a great improvement in terms of safety for the workers. Given the large amounts of water and chemical pollution discharged in the process, the reductions in absolute values represent a significant improvement. A financial assessment was carried out to demonstrate that the proposed new system is 16% more economic than the traditional one.     

Does the smart city policy promote the green growth of the urban economy? Evidence from China

Environmental Science and Pollution Research - Urban governance is an important cornerstone in the modernization of a national governance system. The establishment of smart cities driven by...     

Operational ozone forecasts for the region of Copenhagen by the Danish Meteorological Institute

The Danish Meteorological Institute (DMI) has developed an operational forecasting system for ozone concentrations in the Atmospheric Boundary Layer; this system is called the Danish Atmospheric Chemistry FOrecasting System (DACFOS). At specific sites where real-time ozone concentration measurements are available, a statistical after-treatment of DACFOS’ results adjusts the next 48 h ozone forecasts. This post-processing of DACFOS’ forecasts is based on an adaptive linear regression model using an optimal state estimator algorithm. The regression analysis uses different linear combinations of meteorological parameters (such as temperature, wind speed, surface heat flux and atmospheric boundary layer height) supplied by the Numerical Weather Prediction model DMI-HIRLAM. Several regressions have been tested for six monitoring stations in Denmark and in England, and four of the linear combinations have been selected to be employed in an automatic forecasting system. A statistical study comparing observations and forecasts shows that this system yields higher correlation coefficients as well as smaller biases and RMSE values than DACFOS; the present post-processing thus improves DACFOS’ forecasts. This system has been operational since June 1998 at the DMI's monitoring station in the north of Copenhagen, for which a new ozone forecast is presented every 6 h on the DMI's internet public homepage.     

An ozone precursor monitor for analyzing the ozone-forming potential of the atmosphere

A new air monitoring instrument, the Ozone Precursor Monitor, is described. This device draws ambient air into a reaction chamber and measures its O₃ content before and after irradiation. The change in O₃ content, measured in ozone equivalent units (ppb O₃), represents the ozone-forming potential of the air. Although this measurement is more closely related to O₃-forming potential than other available precursor measurements or emission inventories, differences in temperature, exposure time and intensity, and precursor enrichment or dilution make it site dependent and not equivalent to observed concentrations after exposure to sunlight. However, the O₃-equivalent unit may become a valuable parameter for predicting O₃ concentrations, either as an input to an empirical model or as a mid-point check in the validation of an analytical model.     

Selectivity of Euphorbia lathyris L., to chlortoluron results from the accumulation of the herbicide in the leaves

$\text{Euphorbia lathyris L.}$, was treated for 24 h. with 0.1, 1 and 10 ppm chlortoluron. The induction kinetic of the fluorescence on the whole leaf was registered during the following 15 days. A recovery of $\text{E. lathyris}$ seedlings and an accumulation of chlortoluron in leaves was observed. The fluorescence levels obtained on the leaves emerged after the treatments were similar to the one observed on the control plants. This explains the detoxification mechanism as an accumulation of chlortoluron in the leaves present during the treatment.     

Factors influencing the vertical distribution of microplastics in the beach sediments around the Ras Rakan Island,Qatar

Environmental Science and Pollution Research - Microplastic (MP) pollution is an emerging environmental problem, particularly in the marine environment, and nations are concerned about this issue....     

Increasing the microbial activity in activated sludge by the phenomenon of 'biological resonance

Mechanical oscillations as well as electrical oscillations (e.g. in an electrical oscillatory circuit) can lead to resonance conditions by external agitation with the natural frequency of the system. During the microbial protein synthesis, the induction and repression mechanisms also cause oscillations in the form of varying protein concentrations. The aim of this work concentrates on an induced resonance case of the biological system, comparable with physical resonance phenomena, by external periodic stimulations. For this, system theoretical computer simulations with a structured genetic model were carried out, which built the theoretical fundament for describing the effect of 'Biological Resonance'. Based on that, lab-scale experiments using a mixed microbial culture (activated sludge) and skimmed milk as an inducing substrate revealed an enhanced microbial productivity of around 60%-75% compared to values of the productivity under steady-state conditions in a narrow range of process parameters. The optimum (resonance case) was confirmed by a repetition of the variation experiments and is characterised by a substrate supply period of approx. 18 min and a following starvation period of about 9 min. Long-term investigations under optimised process conditions indicate adaptation mechanisms of the microorganisms to evade the imposed stress conditions. The productivity will not remain constant without additional stimulation and declines to its original level. However, temporal modulation of the starvation period permanently increases the productivity (elevated catabolism) to about 60%, which was observed over a period of several weeks.     

Interaction between components of electroplating industry wastes. Influence of the receiving water on the toxicity of the effluent

A copper-cadmium-nickel-zinc mixture was assessed in seven different river waters to study metal toxicity to the ciliate protozoan Colpidium campylum, the interactions occurring between metals, and the influence of the receiving water on toxicity. In the range of concentrations tested, which are representative of electroplating industry wastes, the main part of the toxicity can be attributed to copper and to cadmium-copper synergy. A classification of waters, based on a principal component analysis (PCA), was used to examine the main parameters of the water, which can affect the toxicity of metal mixtures. It appears that the mineralization of the water, more than the total organic carbon (TOC), is an important parameter for the expression of toxicity. A strategy for the estimation of ecotoxicological hazard assessment, based on a simplified factorial experiment is proposed. It enables one to study, in a two-step bioassay, the toxicity of an effluent, the influence of river water on its toxicity, and the effects of contact time and dilution. By applying PCA to data from very different waters, it may be possible to estimate the ecotoxicological risk associated with the discharge of an effluent, on the basis of the chemistry of the receiving water.     

Some Problems in the Application of the Deutsch Equation to Industrial Electrostatic Precipitation

The Deutsch equation assumes that all particles are identical and that there is complete mixing of the gas at any point along the gas path. In industrial precipitators complete mixing is probably a good approximation but the diversity of sizes and kinds of particles results in an efficiency curve which increases less rapidly with precipitator length than would be predicted by the Deutsch equation. By choosing a different drift velocity for each condition, the Deutsch equation can be effectively used by an expert but this procedure can be very confusing to the engineer with limited experience.