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Posts Tagged ‘Sampling’

Vapor Intrusion Investigations: Air Sampling Tips for Meeting Data Quality Objectives

Monday, September 26th, 2011

N. Dagnillo1, L. Hill2, A. Fortune3, A. Smith4, and S. Thompson2
1Trihydro Corporation, 3001 E. Pershing Blvd, Suite 115, Cheyenne, WY 82007
2Trihydro Corporation, 1537 Riverside Ave., Suite 101, Fort Collins, CO 80524
3Columbia Analytical Services, Inc., 2655 Park Center Drive, Suite A, Simi Valley, CA 93065
4Trihydro Corporation, 9460 Calle Milano, Atascadero, CA 93422

Vapor intrusion is a fate and transport process characterized by the upward movement of volatile chemicals from subsurface contamination (e.g., buried waste, contaminated groundwater) into overlying buildings. The potential for adverse human health effects from exposure to indoor air vapors has motivated private, state, and federal entities to develop guidance documents and protocols specific to the collection and analysis of soil vapor data.

Read more about Vapor Intrusion Investigations…

Reducing Errors through Multi-Increment Sampling

Wednesday, August 18th, 2010

By Gregory Salata, Ph.D.

Multi-Increment Sampling

The objective of environmental sampling is to quantify contamination at a given location. In situations where sample collection may result in discrete samples of a heterogeneous nature, results may be biased based on the particle size of each sub-aliquot collected at the site. One option to help reduce the errors associated with non-uniform sample composition is to use multi-increment sampling (MIS) to create a representative, homogeneous aliquot for analysis of analytes.

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Analytical Testing for 1,4-Dioxane

Tuesday, January 26th, 2010

1,4 Dioxane Testing1,4-Dioxane (dioxane) is a chemical of concern for its potential health effects as a carcinogen and irritant. It is commonly found in personal care products such as detergents, shampoos, body lotions, and cosmetics, and is widely used as an industrial solvent and stabilizer in manufacturing processes (e.g., electronics, metal finishing, fabric cleaning, pharmaceuticals, herbicides, pesticides, antifreeze, paper, etc.). Currently, there are no established limits on the amount of dioxane in personal care products nor is it specifically regulated in manufacturing wastewater streams that may impact the surrounding environment. Manufacturers of personal care products should conduct laboratory analysis to determine the levels of dioxane in their products, and manufacturers using dioxane in their processes should analyze their waste streams for possible dioxane content.

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Air Sampling Media Cleanliness for Vapor Intrusion

Wednesday, November 26th, 2008

The increase in regulatory oversight at vapor intrusion sites nationwide, as well as recent publication of Federal and local vapor intrusion guidance documents and screening levels has led to a need for reliable air phase (indoor air and sub-slab/soil vapor) data at extremely low concentrations. This paper will explore and discuss the importance of media cleanliness and certification to achieve typical low level data quality objectives.

Several potential pathways of media contamination will be examined, including: canisters, flow controllers/critical orifice assemblies, vacuum gauges, and canister pressurization/fill stations in the laboratory.

Several contamination situations will be explored and quantified. The resulting data will be used to support laboratory and field sampling best practice recommendations.

Read the complete air sampling media cleanliness case study… (Acrobat PDF)

Soil Gas Sampling

Tuesday, January 15th, 2008

Soil-Gas-SamplingSoil gas sampling is increasing in frequency across the country as vapor intrusion continues to gain regulatory attention. When evaluating the potential for vapor intrusion at a particular site, it is useful to collect soil gas samples to find out how vapors and contaminants of concern are migrating in the subsurface, and whether or not those vapors are migrating indoors. Soil gas sampling, used in conjunction with state specific screening criteria and/or modeling, is often an intermediate step between screening based on groundwater concentration and collecting indoor air samples.

The goal of soil gas sampling is to collect a sample of the vapor that resides in the interstitial soil pores near a source of contamination and/or near a potential receptor structure. To sample soil gas, a temporary or permanent soil vapor probe is installed. If the well is installed incorrectly or is not sealed properly, leaks to the ambient air may occur. This can dilute or otherwise influence the concentrations seen, potentially leading to incorrect decision making.

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Passive Diffusion Devices & Polyethylene Diffusion Bag (PDB) Samplers

Sunday, October 26th, 2003

Passive Diffusion SamplingPassive Diffusion Samplers are generating a lot of interest in the environmental community for four main reasons:

•Water samples are more representative of the area adjacent to the well screen or area of interest than those taken by other conventional means.
•Well purging is not required.
•They are simple to deploy.
•They are inexpensive when compared to other sampling techniques.

The principle behind passive diffusion is that compounds will migrate or diffuse through a semi-permeable membrane until a concentration equilibrium is established on either side of the membrane. The following three passive devices are currently commercially available or will be soon.

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