A Downhole Passive Sampling System To Avoid Bias and Error from Groundwater Sample Handling

Britt, Sanford L.; Parker, Beth L.; Cherry, John A.

doi:10.1021/es100828u

Cited by 28 publications

(22 citation statements)

References 17 publications

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“…As such, they are well suited for determining depth‐discrete concentrations within a well. Several other grab‐sample devices have been developed and tested extensively, including in situ sealed samplers (i.e., Snap Samplers) (ITRC 2007; Parker and Mulherin 2007; Britt et al 2010). Extensive technical and regulatory guidance has been published, including the results of comparative validation studies.…”

Section: Introductionmentioning

confidence: 99%

Field Investigation of Vapor‐Phase‐Based Groundwater Monitoring

Adamson¹,

McHugh²,

Rysz³

et al. 2011

Groundwater Monitoring Rem

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The use of in‐field analysis of vapor‐phase samples to provide real‐time volatile organic compound (VOC) concentrations in groundwater has the potential to streamline monitoring by simplifying the sample collection and analysis process. A field validation program was completed to (1) evaluate methods for collection of vapor samples from monitoring wells and (2) evaluate the accuracy and precision of field‐portable instruments for the analysis of vapor‐phase samples. The field program evaluated three vapor‐phase sample collection methods: (1) headspace samples from two locations within the well, (2) passive vapor diffusion (PVD) samplers placed at the screened interval of the well, and (3) field vapor headspace analysis of groundwater samples. Two types of instruments were tested: a field‐portable gas chromatograph (GC) and a photoionization detector (PID). Field GC analysis of PVD samples showed no bias and good correlation to laboratory analysis of groundwater collected by low‐flow sampling (slope = 0.96, R2 = 0.85) and laboratory analysis of passive water diffusion bag samples from the well screen (slope = 1.03; R2 = 0.96). Field GC analysis of well headspace samples, either from the upper portion of the well or at the water‐vapor interface, resulted in higher variability and much poorer correlation (consistently biased low) relative to laboratory analysis of groundwater samples collected by low‐flow sample or passive diffusion bags (PDBs) (slope = 0.69 to 0.76; R2 = 0.60 to 0.64). These results indicate that field analysis of vapor‐phase samples can be used to obtain accurate measurements of VOC concentrations in groundwater. However, vapor samples collected from the well headspace were not in equilibrium with water collected from the well screen. Instead, PVD samplers placed in the screened interval represent the most promising approach for field‐based measurement of groundwater concentrations using vapor monitoring techniques and will be the focus of further field testing.

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Section: Introductionmentioning

confidence: 99%

Field Investigation of Vapor‐Phase‐Based Groundwater Monitoring

Adamson¹,

McHugh²,

Rysz³

et al. 2011

Groundwater Monitoring Rem

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“…They use vials introduced into the well in order to avoid volatilization of sampled compounds. One of these devices was compared with sampling at low flow rate after a purge and with PDB on six sites contaminated with volatile organic contaminants [9]. This study showed a good correlation between data obtained with the three methods.…”

Section: Introductionmentioning

confidence: 92%

Validation of a multilevel sampling device to determine the vertical variability of chlorinated solvent in a contaminated aquifer

Barnier¹,

Palmier

Atteia³

2013

Environmental Technology

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The vertical heterogeneity of contaminant concentrations in aquifers is well known, but obtaining representative samples is still a subject of debate. In this paper, the question arises from sites where numerous fully screened wells exist and there is a need to define the vertical distribution of contaminants. For this purpose, several wells were investigated with different techniques on a site contaminated with chlorinated solvents. A core-bored well shows that a tetrachloroethene (PCE) phase is sitting on and infiltrating a less permeable layer. Downstream of the cored well, the following sampling techniques were compared on fully screened wells: low flow pumping at several depths, pumping between packers and a new multilevel sampler for fully screened wells. Concerning low flow rate pumping, very low gradients were found, which may be due to the existence of vertical flow inside the well or in the gravel pack. Sampling between packers gave results comparable with the cores, separating a layer with PCE and trichloroethene from another one with cis 1,2-dichloroethene and vinyl chloride as major compounds. Detailed sampling according to pumped volume shows that even between packers, cleaning of the inter-packer volume is necessary before each sampling. Lastly, the proposed new multilevel sampler gives results similar to the packers but has the advantages of much faster sampling and a constant vertical positioning, which is fairly important for long-term monitoring in highly stratified aquifers.

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“…Brite et al 23 have described a downhole groundwater sampler to reduce bias and error due to sample handling and exposure while introducing minimal distribution to natural flow conditions in the formation and well. This in situ sealed (ISS) or "snap" sampling device includes removable/flab-ready sample bottles, a sampler device to hold double end-opening sample bottles in an open position, and a line for lowering the sampler system and triggering closure of the bottles downhole.…”

Section: Sampling Devicesmentioning

confidence: 99%

Metals in Natural Water Samples

Crompton

2015

Determination of Metals in Natural Waters, Sediments and Soils

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A Downhole Passive Sampling System To Avoid Bias and Error from Groundwater Sample Handling

Cited by 28 publications

References 17 publications

Field Investigation of Vapor‐Phase‐Based Groundwater Monitoring

Field Investigation of Vapor‐Phase‐Based Groundwater Monitoring

Validation of a multilevel sampling device to determine the vertical variability of chlorinated solvent in a contaminated aquifer

Metals in Natural Water Samples

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