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Field Investigation Techniques for Potentially Contaminated Sites
Published in Kofi Asante-Duah, Management of Contaminated Site Problems, 2019
Diffusion sampling is a relatively new technology designed to use passive sampling techniques that eliminate the need for well purging. In fact, groundwater sample collection using diffusion samplers represents a relatively new technology that have traditionally utilized passive sampling methods for monitoring VOCs in groundwater. In this technique, a diffusive-membrane capsule is filled with deionized distilled water, sealed, mounted in a suspension device, and lowered to a specified depth in a monitoring well. Over time (generally no less than 72 h), VOCs in the groundwater diffuse across the capsule membrane and contaminant concentrations in the water inside the sampler attain equilibrium with the ambient groundwater. The sampler is subsequently removed from the well and the water within the diffusion sampler is transferred to a sample container and submitted for laboratory analysis. Once a diffusion sampler is placed in a well, it remains undisturbed until equilibrium is achieved between the water in the well casing and the water in the diffusion sampler. Depending on the hydrogeologic characteristics of the aquifer, the diffusion samplers can reach equilibrium within 3–4 days (Vroblesky and Campbell, 2001)—albeit up to 2 weeks or so may be a reasonable recommended modus operandi. Groundwater samples collected using the diffusion samplers are thought to be representative of water present within the well during the previous 24–72 h. Studies have indeed shown the VOC concentration in undisturbed water within the screened well interval can be representative of concentrations in the adjacent aquifer. Thus, a passive sampling method, such as diffusion samplers, has the potential to provide representative concentrations of aqueous contaminants as they exist in the undisturbed subsurface.
Passive Sampling Strategies for Environmental Monitoring in Air and Aquatic Environment
Published in Leo M. L. Nollet, Dimitra A. Lambropoulou, Chromatographic Analysis of the Environment, 2017
Anna-Akrivi Thomatou, Ioannis Konstantinou
Thus, passive sampling methods are based on either adsorption or absorption of pollutants from water. Adsorptive methods are based on the physical or chemical sorption of analytes on surfaces and depend on surface binding and surface area. Absorptive methods include analyte distribution on the receiving phase and depend mainly on the polarity of the pollutant and the solvent phase and the solubility of the pollutant in water and the solvent.
Introduction
Published in R. A. Jenkins, M. R. Guerin, B. A. Tomkins, The Chemistry of Environmental Tobacco Smoke, 2000
R. A. Jenkins, M. R. Guerin, B. A. Tomkins
Active sampling involves drawing air into collection media by means of a pump. Passive sampling involves placing a material that irreversibly adsorbs, absorbs, or chemically fixes the chemical of interest in the environment being sampled. Active sampling is used to sample large volumes of air or to sample small volumes of air over short durations. Passive sampling is used primarily to sample small volumes of air over long periods of time.
Environmental sampling for disease surveillance: Recent advances and recommendations for best practice
Published in Journal of the Air & Waste Management Association, 2023
Joshua L. Santarpia, Elizabeth Klug, Ashley Ravnholdt, Sean M. Kinahan
In continuous flow-proportional sampling, a small amount of fluid is collected for specified volumes of liquid flowing past the collector. This method requires continuous flow measurement of the waste stream and can be costly to implement. Twenty-four hour composite samples are similar to continuous flow sampling, except that samples are collected at specified time intervals rather than based on flow volume. Both of these methods represent composites of the waste stream over a period of time and therefore temporal variations in the waste stream are not observable. Other sampling methods offer more cost effective solutions. In grab sampling a onetime sample is taken to represent a specified time period. This method can be influenced by temporal variations in the waste stream. However, it has been shown to be effective for SARS-CoV-2 monitoring if the sampling time corresponds with presence of the suspected contaminant (Augusto et al. 2022; Kmush et al. 2022). Passive sampling (Bivins et al. 2022; Rafiee et al. 2021) involves the collection of the analyte of interest on a collection medium that is submerged in the waste stream to accumulate time-integrated samples.
Efficient passive sampler using copper oxide micro-adsorbent for the detection of volatile sulfur compounds (VSCs) from the small lab-scale spilled crude oil
Published in Petroleum Science and Technology, 2022
Hozan Jalal Saleem, Yousif Mustafa Salih, Luqman Omar Hamasalih, Khalid M. Omer
Several methods have been used to detect and collect of VSCs in polluted environments such as using solid phase micro extraction (SPME) technique (Nielsen and Jonsson 2002; Li and Shooter 2004; Kabir and Kim 2012; Lu et al. 2012), active sampling technique (Xu et al. 2020), portable VSC detectors (Yaegaki et al. 2012) and passive sampler methods (Mason et al. 2011). The passive sampling methods have been used lately as a cheap, simple-to-use and reliable technique for measuring ambient pollutants. Passive sampler was described as any sampling technique depend on the free flow of analyte molecule from surrounded medium to receiving phase in the passive sampler, as a consequence from various chemical potential between environments of both medium. The receiving phase can be solvent, chemical reagent or any probable porous adsorbent (Vrana et al. 2005). The most customarily used adsorbent in passive sampling is charcoal with is equipped with different types of passive samplers which are commercially available and have been used for the collection of environmental volatile component concentrations in indoor and outdoor air (Begerow et al. 1999).
Passive personal air sampling of dust in a working environment—A pilot study
Published in Journal of Occupational and Environmental Hygiene, 2019
Mariam Shirdel, Ingvar A. Bergdahl, Britt M. Andersson, Håkan Wingfors, Johan N. Sommar, Ingrid E. Liljelind
Occupational exposure to particles can lead to different health effects among workers.[1–3] Measuring occupational exposure by using active sampling requires a working pump and special expertise for maintenance and sampling. The cost of obtaining samples with the expertise of industrial hygienists can therefore be high considering the time required and the operational costs. A cost-effective and simpler alternative to active sampling is passive sampling,[4] which is also less disturbing for the worker. Passive sampling does not rely on a pump and requires no power supply; it uses gravity and diffusion to collect particles.