Prospects and limitations of phytoremediation for the removal of persistent pesticides in the environment

The environmental problems that have arisen from the use of persistent pesticides in the past, and potential sources of further contamination have been discussed. The potential and limitations of phytoremediation for removal of pesticides in the environment have been reviewed. The enzymatic processes in plants that are known to be involved in phytodegradation of pesticides, and possibilities for enhancing them have also been discussed.     

The application of piezoelectric detectors for investigations of environmental pollution

The general properties of piezoelectric sorption detectors utilised in the detection of air pollution have been characterised. Examples of detection, with the aid of these detectors, of the organophosphorus compounds, sulphur dioxide, ammonia, hydrocarbons and their derivatives and other air pollutants have been given. Based on information given in this paper, general conclusions including advantages, and difficulties of using piezoelectric detectors in practice have been described.     

Comparison of EGR ratios determined by four different methods for electronic re-circulation gate control

In this study, low pressure systems have been applied for exhaust gas recycling (EGR), which is applied in certain operating conditions. Induction air, exhaust gas flow, amount of exhaust gas added to the induction air, amount of carbon dioxide (CO₂) in the exhaust gas, and amount of carbon dioxide in the induction air mixed with the exhaust gas, have been measured and the EGR ratio has been determined using four different calculation methods. The obtained results have been compared, and it has been noted that all the four methods have given similar results, and the deviation among them has been noted to be 1% at most. Deviations among the results have been explained. In the concluding section, a relation has been formed between the variables chosen as basic parameters, electronic re-circulation gate control, and variables utilised in EGR ratio determination methods.     

Pesticide contamination of ground water in the United States--a review

Over 70 pesticides have been detected in ground water. Aldicarb and atrazine along with the soil fumigants EDB and DCP and DBCP have been the pesticides most frequently detected in ground water. Atrazine concentrations have been correlated with high nitrate concentrations. The triazine herbicides, simazine and cyanazine, have also been detected in ground water. The annual amount of recharge, soil type, depth of aquifer from the surface, nitrate contamination and soil pH are important field parameters in determining ground-water contamination potential by pesticides. Pesticide leaching is reduced by proper choice of crop rotation, increasing pesticide application efficiency, and integrated pest management.     

Paper electrophoretic separations of some common pesticides : Determination of monocrotophos,rogor and malathion in soil samples

Abstract

Paper electrophoretic movements of a number of pesticides belonging to organophosphorus, organochlorine and pyethroid groups in various acid background electrolytes have been studied. The effect of pH and pKa of the acids on the movement of these pesticides have also been studied. It has been observed that the movement of most of the pesticides is enhanced with increase in the degree of ionisation of the acids (pKa) studied as background electrolytes. The movement also increases with increase in the pH of acids. On the basis of differential movement of pesticides towards cathode and anode, a number of separations have been achieved from binary mixtures. Monocrotophos, rogor and malathion have been determined quantitatively (28.6 ‐ 29.2 μg) in alcoholic extracts of soil samples.     

高浓度难降解有机废水的催化氧化技术及其进展

根据催化剂的激活因子不同 ,本文将催化氧化法分为湿式催化氧化法 (WCO)、光催化氧化法 (PCO)和电催化氧化法 (ECO)三种 ,并阐述了各自的反应机理及应用研究状况 ,提出了今后需要加强的研究方向     

Accumulation of chlorinated hydrocarbon vapours in pine needles

Needles with different ages from four pines have been analysed for PCB's, HCB, α- and γ-HCH, p,p'DDT and DDE. The accumulation found has been discussed and provisional accumulation rates under actual background conditions have been calculated.     

开发区实施循环经济的环境管理探讨--以苏州高新区为例

以苏州高新区为例，指出了主要环境问题，分析了实施循环经济的环境管理现状及不足，并重点提出了实施循环经济的环境管理对策，为开发区按循环经济的规律运行作了有益的探索，也为循环经济的顺利开展提供了科学依据。     

武钢焦化公司酚氰废水治理现状及改进措施

本文介绍了武钢焦化公司酚氰废水的来源、治理的原理、工艺流程及运行现状 ,并对一些环节提出了具体的改进措施和建议。     

Microstructural characterisation of keratin fibres from chicken feathers

Natural fibres have recently attracted scientists' attention because of their advantages from the environmental standpoint. However, almost all the research has been directed towards cellulose from vegetal sources without taking into account other potentially interesting compounds like keratin, which can be found in feathers, wool, nail or hair. In spite of its strength, low density and biodegradability, keratin has been studied only from the medical and textile point of view, whereas others aspects have not been highlighted. The object of this work is to give an exhaustive characterisation of one of the most abundant sources of keratin fibre, that is, of chicken feather. To accomplish this programme we have made spectroscopic analysis using both Fourier transform, infrared and Raman thermal analysis including differential scanning calorimetry and thermogravimetric analysis, and contact angle determinations. Finally optical, transmission and scanning electron microscopy have been realised to ensure a full characterisation.     

Comparative toxicity of some pesticides on human health and some aquatic species

Inhibition studies have been carried on the hydrolysis reactions catalyzed by cholinesterases taken from electric eel, human and horse serums by Sevin, Aldrin and Malathion. Three esters of p-nitrophenol have been used as substrates. The degree of inhibition has been used as a measure of the comparative toxicity of these pesticides on these cholinesterases.     

Evaluation of Dust Generated from Basic Oxygen Furnace Steel Making

Abstract

A detailed characterization has been made of the dust generated during steel making in basic oxygen furnaces (BOF). Chemical composition and particle size distribution have been analyzed. X-ray diffraction, scanning electron microscopy, and electron probe micro-analysis techniques have been used to identify the morphology and the nature of the major iron-bearing phases as well as the gangue constituents. The dust characteristics have been found to be widely different, depending on the type of process used in BOF steel making, namely, suppressed combustion or total combustion. The type of dust abatement system (dry or wet) additionally influences the nature of the gangue constituents. The possibility of utilizing the iron-bearing major phases has been examined.     

Parasites and pollution: the effectiveness of tiny organisms in assessing the quality of aquatic ecosystems,with a focus on Africa

The aquatic environment represents the final repository for many human-generated pollutants associated with anthropogenic activities. The quality of natural freshwater systems is easily disrupted by the introduction of pollutants from urban, industrial and agricultural processes. To assess the extent of chemical perturbation and associated environmental degradation, physico-chemical parameters have been monitored in conjunction with biota in numerous biological monitoring protocols. Most studies incorporating organisms into such approaches have focussed on fish and macroinvertebrates. More recently, interest in the ecology of parasites in relation to environmental monitoring has indicated that these organisms are sensitive towards the quality of the macroenvironment. Variable responses towards exposure to pollution have been identified at the population and component community level of a number of parasites. Furthermore, such responses have been found to differ with the type of pollutant and the lifestyle of the parasite. Generally, endoparasite infection levels have been shown to become elevated in relation to poorer water quality conditions, while ectoparasites are more sensitive, and exposure to contaminated environments resulted in a decline in ectoparasite infections. Furthermore, endoparasites have been found to be suitable accumulation indicators for monitoring levels of several trace elements and metals in the environment. The ability of these organisms to accumulate metals has further been observed to be of benefit to the host, resulting in decreased somatic metal levels in infected hosts. These trends have similarly been found for host–parasite models in African freshwater environments, but such analyses are comparatively sparse compared to other countries. Recently, studies on diplozoids from two freshwater systems have indicated that exposure to poorer water quality resulted in decreased infections. In the Vaal River, the poor water quality resulted in the extinction of the parasite from a site below the Vaal River Barrage. Laboratory exposures have further indicated that oncomiracidia of Paradiplozoon ichthyoxanthon are sensitive to exposure to dissolved aluminium. Overall, parasites from African freshwater and marine ecosystems have merit as effect and accumulation indicators; however, more research is required to detail the effects of exposure on sensitive biological processes within these organisms.     

Kinetics of photocatalytic VOCs abatement in a standardized reactor

A standardized micro-pilot scale continuous flow apparatus has been built up, using two types of differential photoreactors, and equipped with a refined control of the working conditions in order to study the photocatalytic degradation as a way to abate VOCs in air. Kinetic measurements have been carried out on trichloroethylene (TCE), methanol and benzene as model pollutants. The absence of diffusional limitation and of reaction product effect on the kinetics have both been demonstrated under our working conditions. The influences of concentration, light flux and temperature on the initial degradation rate have been studied. A simple Langmuir-Hinshelwood kinetic model has been verified for TCE and methanol, whereas benzene degradation was more complex and did not follow this simple mechanism. The determined experimental data aim at being useful in the scaling-up of photocatalytic reactors.     

Use of ozone and/or UV in the treatment of effluents from board paper industry

The aim of this work has been to study the viability of ozone and/or UV in the treatment of cardboard industry effluents. Several model compounds have been chosen for the experiments: guaicol, eugenol, glucose, acetate and butyrate. Significant differences in the ozonisation rates are observed between phenolic products coming from lignin (eugenol and guaiacol) and aliphatic compounds. Reactions fit in all cases a pseudo-first order kinetics and are influenced by the pH of the solution. Real effluents have also been tested, and the COD decrease has been found to depend on the fatty acids/phenols ratio. Finally, respirometric studies have shown an increase in the BODst in effluents subjected to a mild oxidation, while under stronger conditions a BODst decrease is observed.     

Texas Regulation Requires Control of Opacity Using Instrumental Measurements

For over four years, a Texas air pollution control regulation has been in force which permits use of a stack mounted transmissometer instrument to measure visible emissions, thus avoiding the necessity for visual observations. Many types of industrial plants have installed instruments, and extensive experience has been obtained with this method of measurement and control. Plant operators and enforcement officials have expressed a strong preference for this method, both to demonstrate compliance and to provide data to aid in operating control equipment. Some operational problems have been encountered, but these usually can be overcome with proper care. Because of the advantages obtained with this regulation a new regulation has been adopted which makes the instrumental method mandatory for large sources of visible emissions.     

Tracking of phenol degrading genotype

A simple and rapid protocol has been developed for monitoring of the phenol degrading population in the environmental samples. PCR protocol uses the total DNA prepared from the samples as a template in the amplification reaction. Primers have been designed from the sequence data for Dmp and Phe operon encoding multi-component and single component phenol oxidizing system, respectively. The phenol degrading genotype in various samples have been demonstrated using the developed PCR protocol.     

Air Pollution Impacts to Some Important Species of Pine

In the past, many species of pine have been severely damaged by acute forms of air pollution associated with ore smelting. More recently, damage to ponderosa pine in the state of Washington has been associated with atmospheric fluoride, and this species in particular has also suffered smog damage in southern California. In the East, white pine has been declining in the vicinity of certain soft-coal-burning power plants, and in one case downwind from an oil-burning power plant: also, throughout the East, an atmospheric oxidant of unknown source has caused a type of needle blight on white pine. Trash burners and city dump combustion have led to the hilling of certain pine species, leaving other intermixed pine species unharmed. Localized damage to white pine from automobile exhaust has been observed. Differences in the susceptibility of neighboring trees of the same species to a given air pollutant have been observed repeatedly.     

Manual Procedures for the Estimation of Atmospheric Fluorides

Manual methods for the determination of air-borne fluorides, including the discrimination of gaseous and particulate forms, have been reviewed. Published methods have been re-examined and comparative sampling data presented, to point out advantages of some newer techniques in sampling, separation, and quantitation.