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Changes in sample collection and analytical techniques and effects on retrospective comparability of low-level concentrations of trace elements in ground water

Water Research

By:
, ,
DOI: 10.1016/S0043-1354(01)00094-X

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Abstract

Ground-water sampling techniques were modified to reduce random low-level contamination during collection of filtered water samples for determination of trace-element concentrations. The modified sampling techniques were first used in New Jersey by the US Geological Survey in 1994 along with inductively coupled plasma-mass spectrometry (ICP-MS) analysis to determine the concentrations of 18 trace elements at the one microgram-per-liter (??g/L) level in the oxic water of the unconfined sand and gravel Kirkwood-Cohansey aquifer system. The revised technique tested included a combination of the following: collection of samples (1) with flow rates of about 2L per minute, (2) through acid-washed single-use disposable tubing and (3) a single-use disposable 0.45-??m pore size capsule filter, (4) contained within portable glove boxes, (5) in a dedicated clean sampling van, (6) only after turbidity stabilized at values less than 2 nephelometric turbidity units (NTU), when possible. Quality-assurance data, obtained from equipment blanks and split samples, indicated that trace element concentrations, with the exception of iron, chromium, aluminum, and zinc, measured in the samples collected in 1994 were not subject to random contamination at 1??g/L.Results from samples collected in 1994 were compared to those from samples collected in 1991 from the same 12 PVC-cased observation wells using the available sampling and analytical techniques at that time. Concentrations of copper, lead, manganese and zinc were statistically significantly lower in samples collected in 1994 than in 1991. Sampling techniques used in 1994 likely provided trace-element data that represented concentrations in the aquifer with less bias than data from 1991 when samples were collected without the same degree of attention to sample handling. Copyright ?? 2001 .

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Changes in sample collection and analytical techniques and effects on retrospective comparability of low-level concentrations of trace elements in ground water
Series title:
Water Research
DOI:
10.1016/S0043-1354(01)00094-X
Volume
35
Issue:
15
Year Published:
2001
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Water Research
First page:
3611
Last page:
3624
Number of Pages:
14