Evaluation of working air quality by using semipermeable membrane devices. Analysis of organophosphorus pesticides

It has been evaluated the use of semipermeable membrane devices (SPMDs) as passive samplers of organophosphorus pesticides from air, in order to determine the contamination of working environments. Additionally, the use of SPMDs as portable samplers has been also considered. The analytical methodology for the determination of diazinon, chlorpyrifos-methyl, pirimiphos-methyl, chlorpyrifos and fenthion in SPMDs exposed to contaminated air was based on microwave-assisted extraction and gas chromatography with mass spectrometry determination. Limit of detection (LOD) values from 2 to 4 ng SPMD⁻¹ and repeatability from 2 to 7% were obtained by using the aforementioned methodology. Theoretical calculated sampling rates were employed for the estimation of the pesticide concentration in air, by using the pesticide mass retained in the deployed SPMD. The obtained LOD values, for a sampling time of 7 days, were from 1 to 2 ng m⁻³. The evaluation of the air quality of a pesticide laboratory with an intensive use of diazinon and chlorpyrifos has been made in order to check the operation safety conditions.     

Determination of volatile organic compounds in contaminated air using semipermeable membrane devices

Semipermeable membrane devices (SPMDs) were evaluated as passive samplers for the determination of 26 volatile organic compounds (VOCs) in contaminated air of occupational environments. A direct methodology based on the use of head-space-gas chromatography-mass spectrometry (HS-GC-MS) was developed for VOCs determinations in SPMDs, without any sample pre-treatment and avoiding the use of solvents. A desorption temperature of 150 °C for 10 min was sufficient for a sensitive VOCs determination providing limits of detection in the range of 15 ng SPMD⁻¹ for 21 of 26 studied compounds. Linear and equilibrium uptake models were established for each VOC from compound isotherms. Highly volatile compounds were slightly absorbed and moderately volatile compounds were strongly absorbed by SPMDs. This study is the first precedent of the use of SPMDs for the simultaneous sampling of a wide number of VOCs. The use of SPMDs is a simple and low cost alternative to ordinary sampling devices such as Radiello^® diffusive samplers or badge-type solid-phase supports.     

An Electrochemical Monitor for Air Pollutants

Abstract

A thin-layer electrochemical cell has been developed as a detector for air pollutants, and tested with S0₂-air and Cl₂-air mixtures. The cell gives well-defined, reproducible signals proportional to pollutant concentrations down to 20 ppb. Two electroanalytical procedures are described for monitoring or sampling polluted air with the cell: (1) a controlled-potential experiment in which the current-time response of the cell is related to pollutant concentration, and (2) an experiment similar to stripping analysis in which pollutants are first accumulated at an electrode surface under controlled potential conditions, and then analyzed voltammetrically.     

Microwave-assisted extraction of OCPs, PCBs and PAHs concentrated by semi-permeable membrane devices (SPMDs)

Microwave-assisted extraction (MAE) has been evaluated as an alternative to dialysis for extraction of some water-borne hydrophobic contaminants sampled by semi-permeable membrane devices (SPMDs). Seven organochlorine pesticides (OCPs), 11 polychlorinated biphenyls (PCBs) and 13 polycyclic aromatic hydrocarbons (PAHs) were accumulated in SPMDs at nanogram levels and extracted with three 3-min irradiation cycles with 33 mL of a solvent mixture hexane–water (10:1,v/v) in each cycle. The developed MAE method gave for all analytes investigated statistically comparable extraction yields with those found by dialysis carried out with a total volume of 250 mL hexane for 48 h at room temperature. The recoveries of all the targeted contaminants were in the range of 65–105% with variation coefficients not exceeding 19%. The applicability of the MAE extraction was tested in field SPMDs samples deployed for 15 days in a sewage-treatment process. Our results show that MAE provides a remarkable reduction of time and solvent volume when used as an extraction method in the analysis of SPMDs.     

An overview of emerging pollutants in air: Method of analysis and potential public health concern from human environmental exposure

Air pollutants are perhaps the largest cause of diseases and death in the world today. Increasing urbanization and industrialization have caused an increase in number of diverse forms and types of new pollutants, which are difficult to detect and characterize due to their stench behaviour and complex sources of production. Such pollutants have been called emerging pollutants (EPs) and their list is ever increasing. Therefore, the understanding of the method of analysis and health implication of (EPs) in air is critical to providing a more robust understanding of exposure routes, regulations and mitigation. EPs in air discussed in this study are not in any way exhaustive but limited to emerging VOCs (including acrylonitrile, 1−3-butadiene, chloroform, dichloromethane, ethylene oxides, formaldehyde, toluene, trichloroethylene, 1,4-Dioxane) and metals (arsenic, manganese, and vanadium), ultrafine particles, micro- and nano- plastics, engineered nanoparticles, diesel/black carbon and bioaerosols. Occurrence, detection and health implications of these EPs in air are still unfolding due to limited monitoring studies, lack of standard methodology and regulations. To address this knowledge gap, authors conducted an in-depth review of available information. Their spatial distribution, analytical methods and health implications are discussed including the novel coronavirus (COVID-19) as a potential EP in air. The study concluded with highlights of gaps in knowledge and suggestions to key areas for future research. This information is of general interest to environmental scientists and of specific interest to both health and sanitation workers and policymakers at private, government and international organizations.     

Efficiency assessment of wastewater treatment plant based on SPMD sampling

The efficiency of treatment processes forboth municipal and industrial wastewater (treatment plant-Ostrava, Czech Republic) focused on persistent organic pollutants (POPs) was assessed. Semipermeable membrane devices (SPMDs) as a sampling system were applied. Exposed SPMDs were analyzed both for chemical contaminants of POPs and toxicity response. The chemical analyses of PAHs were made by HPLC-FLD, PCDD/Fs and PCBs were analysed by GC/MS/MS on GCQ or PolarisQ (Thermoquest). Ecotoxicity data on chlorococcal alga Desmodesmus subspicatus (Scenedesmus subspicatus) and luminescent bacteria Vibrio fischeri are presented here. All toxicity data as effective volume Vtox are expressed. The results show good treatment ability of the treatment plant and proved used system as an appropriate tool for efficiency assessment of treatment and/or decontamination processes.     

Determination of oxygenated volatile organic compounds in ambient air using canister collection-gas chromatography/mass spectrometry.

This research attempts to establish a method to measure 11 kinds of oxygenated volatile organic compound (OVOC) in ambient air by using the canister collection-gas chromatography/mass spectrometry (GC/MS) method. Since several compounds such as acetone exhibited high blank concentrations due to their laboratory use, stringent quality control was conducted for the VOC-free added water and the VOC-free nitrogen gas. In order to prevent the decline of recovery rates due to lack of sufficient relative humidity, it is necessary to add VOC-free water when pressurizing and diluting the air samples. Thus, all the target compounds in ambient air were obtained from the canisters at high recovery rates without significant contamination. Furthermore, the canister collection-GC/MS method makes it possible to apply simultaneous air monitoring of OVOCs as well as volatile hazardous air pollutants without additional sampling.     

Considerations involved with the use of semipermeable membrane devices for monitoring environmental contaminants

Semipermeable membrane devices (SPMDs) are used with increasing frequency, and throughout the world as samplers of organic contaminants. The devices can be used to detect a variety of lipophilic chemicals in water, sediment/soil, and air. SPMDs are designed to sample nonpolar, hydrophobic chemicals. The maximum concentration factor achievable for a particular chemical is proportional to its octanol-water partition coefficient. Techniques used for cleanup of SPMD extracts for targeted analytes and for general screening by full-scan mass spectrometry do not differ greatly from techniques used for extracts of other matrices. However, SPMD extracts contain potential interferences that are specific to the membrane-lipid matrix. Procedures have been developed or modified to alleviate these potential interferences. The SPMD approach has been demonstrated to be applicable to sequestering and analyzing a wide array of environmental contaminants including organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polychlorinated dioxins and dibenzofurans, selected organophosphate pesticides and pyrethroid insecticides, and other nonpolar organic chemicals. We present herein an overview of effective procedural steps for analyzing exposed SPMDs for trace to ultra-trace levels of contaminants sequestered from environmental matrices.     

Evaluation of the possibility of detecting benzenic pollutants by direct spectrophotometry on PDMS solid sorbent

Solid-phase extraction has become one of the most commonly used techniques for preconcentration of analytes from environmental samples. In the standard use of solid sorbent phases the extracted pollutants are subsequently eluted with a suitable organic solvent before chromatographic analysis. An alternative to this procedure is analysis of the adsorbed and concentrated pollutants by direct application of a spectroscopic method (fluorimetry or absorptiometry) to the phase. Although this method cannot be expected to give results as precise as those given by chromatographic methods, it might have valuable applications, particularly for "on site" pollution monitoring. This paper reports an evaluation of the capability of the method for the spectrophotometric detection of BTX (benzene, toluene, xylenes) in aqueous media and in contaminated atmospheres, with polydimethylsiloxane (PDMS) as sorbent. The tests performed, with the estimated detection limits, indicate that the method is relatively simple and easy to operate and sensitive enough for application to the monitoring of pollution both in water and in air in an industrial ambient atmosphere.     

Analysis of Air Toxic Compounds by Using Chromatography and Computer-Assisted FTIR Intelligent Method

In the Title Ⅲ of Clean Air Act Amendments of 1990,a list of 189 air toxic compounds were identified to be controlled from stationary source emissions,which means that US EPA must have the capability to quantitatively measure the emissions of these pollutants. FTIR is considered to have great potential in measurement emissions of substantial number of toxic organic air pollutants of interest to US EPA. However,not much of the FTIR work was conducted for stationary source emissions, and too little is known about its applicability and reliability for monitoring toxic air pollutant source emissions. US EPA needs a worldwide international cooperation to understand the advantages and disadvantages of FTIR and signed the cooperative agreement with us in 1994:Research on FTIR (Including its Utility) for Monitoring Toxic Air Pollutants in Stack Gas Emissions (Contract No.:CR822820-01).     

Working principle and application of photocatalytic optical fibers for the degradation and conversion of gaseous pollutants

Photocatalytic optical fibers are promising for the degradation of gaseous and volatile pollutants in air due to their high specific surface area, high light utilization efficiency, easy regeneration, and sustainability. In particular, photocatalytic optical fibers have proven highly useful for the removal and conversion of different kinds of air pollutants in air. However, these fibers suffer from low photocatalytic degradation efficiencies. In this review, we have focused on introducing photocatalytic quartz optical fibers and photocatalytic plastic optical fibers for the degradation and transformation of gas-phase air pollutants. The principle of photocatalytic optical fibers and main methods for improving their photocatalytic and light utilization efficiencies based on semiconductor photocatalytic coatings are summarized. Moreover, the Langmuir-Hinshelwood kinetic rate equation was summarized to analyze the photocatalytic reduction of gaseous pollutants. Finally, an outlook on the future of photocatalytic optical fibers toward the removal and conversion of gaseous air pollutants is discussed.     

Simultaneous selective detection of organophosphate and phthalate esters using gas chromatography with positive ion chemical ionization tandem mass spectrometry and its application to indoor air and dust

A selective and sensitive method for the simultaneous determination of 14 organophosphate and six phthalate esters using gas chromatography (GC) and mass spectrometry (MS) is presented. Both of these compound classes are frequently found in the indoor environment due to their use as bulk additives in numerous polymers, consumer products and building materials. GC/MS utilizing positive ion chemical ionisation (PICI) in selected reaction monitoring (SRM) mode with isobutane as the reagent gas was found to be the best of the tested methods; it proved superior to electron ionisation (EI) in selected ion monitoring (SIM) mode and to PICI using methane as the reagent gas. The method was applied to indoor air samples collected by active air sampling using solid‐phase extraction (SPE) cartridges. Organophosphates and phthalates were simultaneously determined with method detection limits (MDLs) in the range of 0.1–47 ng m^?3. For most compounds the MDLs were ≤0.2 ng m^?3, but due to the presence of some of these ubiquitous indoor air pollutants in the blanks, significantly higher MDLs were observed for a few compounds. Finally, the method was also applied in the screening of a much more complex sample matrix, indoor dust. Copyright © 2010 John Wiley & Sons, Ltd.     

一种新的有机污染物采样装置

介绍了一种由类脂物和半透膜组成的采样装置,该装置可模拟生物监测可被生物订的有机污染物。将其用于监测大气、水体、沉积物中的多氯联苯（ＰＣＢｓ）、有机氯农药（ＯＣＰ）和多环芳烃（ＰＡＨｓ）时,结果满意。     

Trace gas analysis for the evaluation of zero air generators

Trace amount of substance fractions of air pollutants in zero air are measured applying sensitive analytical methods in combination with the infrastructure to operate zero air generators under simulated field conditions at place. The uncertainties of the amount of substance fractions of a diluted standard gas mixture and the dilution offsets are calculated under conditions that consider the effect of trace amounts of analyte in the zero gas with increasing dilution of a gravimetric gas standard. The analytical methods and their calibration, the test procedure and results for various zero air generators are described. The results are compared with the specifications, the Swiss regulatory requirements and the European norms for monitoring ambient air pollutants. By knowing the residual amount of substance of the analyte in a zero gas, the instrument offsets by dilution can be eliminated and the uncertainties for the measurement values of the diluted standard gas mixtures be calculated.     

High-performance liquid chromatography-UV diode array,inductively coupled plasma mass spectrometry (ICMPS) and orthogonal acceleration time-of-flight mass spectrometry (oa-TOFMS) applied to the simultaneous detection and identification of metabolites of 4-bromoaniline in rat urine

Summary The paper describes the role and tasks of environmental analysis and monitoring. It emphasises the leading role played by gas chromatography, especially when coupled with suitable sample preparation. This is demonstrated by some literature evidence and mainly by the author's original work on the design of sample preparation apparatus and development of GC-based methods of determination of a wide variety of organic pollutants in environmental samples. A typical example is the physical speciation of PAHs and PCBs in river environment with the use of a home-made filtration vessel coupled with SPE cartridges to prepare samples for GC-MS analysis; thin layer head space with self-generation of aqueous concentrate to prepare humane urine samples for DAI (direct aqueous injection)-GC-ECD analysis for the content of volatile chloro-organic compounds; studies on capillary denuders in sampling organic air pollutants; passive dosimeters in indoor air quality measurements; design and application of thermal desorbers for the introduction of analytes into GC columns and modification of a speciation analyser for organometalic environmental pollutants. Presented at Balaton Symposium '01 on High-Performance Separation Methods, Siófok, Hungary, September 2–4, 2001     

A fiber-optic sensor system for monitoring chlorinated hydrocarbon pollutants

We have developed and field-tested a fiber-optic chemical sensor system for use in environmental monitoring and remediation. The system detects chlorinated hydrocarbon pollutants with colorimetry, and is based on an irreversible chemical reaction between the target compound and a specific reagent. The reaction products are detected by their absorption at 560 nm and can be monitored remotely with optical fibers. Continuous measurements are made possible by renewing the reagent from a reservoir with a miniature pumping system. The sensor has been evaluated against gas chromatography standards and has demonstrated accuracy and sensitivity (5 ppbw) sufficient for the environmental monitoring of trichloroethylene and chloroform. Successful preliminary field tests have been conducted in a variety of contamination monitoring scenarios.     

Diagnosis of Air Pollution by Microwave Spectroscopy

A review is made of the current state-of-the-art of microwave spectroscopy, and of the feasibility of using this technique in the detection of gaseous pollutants in air. The possibility of applying ultraviolet, visible, and infrared spectroscopic methods to the microwave region is investigated. This is a relatively new application of microwave spectroscopy; only one work was done in the area before 1966, and no results from it were published.

Present experimental work, being done by the authors, is explained. This is divided into two phases. First, basic measurements are being made to determine the limits of pressure over which small concentrations of pollutants may be measured in air. Second, methods are being investigated for adapting the techniques of microwave spectroscopy to the detection of gaseous pollutants. Specifically, it is desired to develop an instrument which will quantitatively detect pollutants at atmospheric pressures. This instrument may be incorporated in a system for air pollution monitoring over large expanses from remote stations, or stack monitoring.     

Configurations and calibration methods for passive sampling techniques

Passive sampling technology has developed very quickly in the past 15 years, and is widely used for the monitoring of pollutants in different environments. The design and quantification of passive sampling devices require an appropriate calibration method. Current calibration methods that exist for passive sampling, including equilibrium extraction, linear uptake, and kinetic calibration, are presented in this review. A number of state-of-the-art passive sampling devices that can be used for aqueous and air monitoring are introduced according to their calibration methods.     

Removal and sensing of emerging pollutants released from (micro)plastic degradation: Strategies based on boron-doped diamond electrodes

The negative impacts of microplastics on the environment and human health cannot be unnoticed. Several classes of emerging pollutants with endocrine-disrupting properties such as bisphenol A and its analogs, phthalates, among others, have been reported to migrate out of plastics entering the aquatic environment. Thus, this review aims to draw attention to the significant potential of the boron-doped diamond electrode to contribute to the implementation of mitigation actions for microplastic pollutants. The latest studies in the two main fields of the use of the boron-doped diamond electrode, that is, treatment of wastewater by electrochemical oxidation and a as sensor for pollutants monitoring, are herein reviewed and their main findings highlighted.     

Continuous emission monitoring of metal aerosol concentrations in atmospheric air

Improvements of an apparatus for continuous emission monitoring (CEM) by inductively coupled plasma atomic emission spectrometry (ICP-AES) of metal aerosols in air are described. The method simultaneously offers low operating costs, large volume of tested air for valuable sampling and avoids supplementary contamination or keeping of the air pollutant concentrations. Questions related to detection and calibration are discussed. The detection limits (DL) obtained for the eight pollutants studied are lower than the recommended threshold limit values (TLV) and as satisfactory as the results obtained with other CEM methods involving air-argon plasmas.