ISO/TR 18105:2014
(Main)Soil quality — Detection of water soluble chromium(VI) using a ready-to-use test-kit method
Soil quality — Detection of water soluble chromium(VI) using a ready-to-use test-kit method
ISO/TR 18105:2014 describes the procedure to screen soil samples to detect Cr(VI) using test-kits based on water extraction of Cr(VI) in soil. The test-kit approach in this method is designed to quickly screen soil samples using calibration to indicate the concentration level.
Qualité du sol — Détection du chrome(VI) soluble dans l'eau en utilisant un kit d'essai prêt à l'emploi
General Information
Standards Content (Sample)
TECHNICAL ISO/TR
REPORT 18105
First edition
2014-05-15
Soil quality — Detection of water
soluble chromium(VI) using a ready-
to-use test-kit method
Qualité du sol — Détection du chrome(VI) soluble dans l’eau en
utilisant un kit d’essai prêt à l’emploi
Reference number
ISO/TR 18105:2014(E)
©
ISO 2014
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ISO/TR 18105:2014(E)
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ISO/TR 18105:2014(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 References . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 2
6 Interferences . 2
7 Apparatus . 2
8 Procedure. 2
8.1 Calibration . 2
8.2 Sample detection . 2
8.3 Measurement . 2
9 Quality assurance (QA) and quality control (QC) . 3
10 Test report . 3
Annex A (informative) Extraction of Cr(VI) from soil CRMs . 4
Annex B (informative) Comparison of Cr(VI) results obtained with commercially
available test-kits . 7
Annex C (informative) Simulation of mapping distributions of Cr(VI) contaminating
potential land . 8
Bibliography .14
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ISO/TR 18105:2014(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information.
The committee responsible for this document is ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical
methods and soil characteristics.
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ISO/TR 18105:2014(E)
Introduction
A test-kit method uses reagents stored in plastic or glass vials prepared for colorimetric detection of
specific compounds soluble with water. There is a lot of varieties of test-kits developed mainly for the
compounds in water samples based on well-known reactions with commonly-used and chemically
stable reagents indicating constant magnitudes of intensities of the signals from target compounds.
The common reactions employed for the test-kit usually give colour, by which the user can recognize
the concentration level of the compound without absorption spectrophotometers even in the situation
when such instruments are not available. Thus, the test-kit determination of the compound in water
samples can be used to screen specific compounds in soil samples, if they are easily dissolved into water.
The reaction applied depends on the target compounds. For chromium(VI), a reaction is used, where
1,5-diphenylcarbazide is used, its isomer or derivatives. When other chemicals or derivatives are used,
the performance is intended to be similar to that obtained with the original reagents. The test-kit
consisting of the reagents has to be identified by confirming the spectrum including intensities at a
specific wavelength. The spectrum shape should be similar to each other between those from test-kits
and bulk reagents commonly used for absorptiometry in laboratories. The intensities and varieties of
interferences to the test-kit method should be within those taking place to absorptiometry test methods
with bulk reagents. The quality or purity of the reagents packed in test-kits should keep constant with a
deviation around that for the bulk reagents for absorptiometry. The detection limit and working curves
available with test-kits should be confirmed in prior of the use.
When screening contaminated sites for Cr(VI) by test-kit detection, Cr(VI) is extracted from soil into
water. The recovery of extracted Cr(VI) would be slightly lower than that when extracting with alkali
solution; however, the repeatability of test-kit detection for Cr(VI) is high enough to apply the detection
manner to contaminated sites as a screening method. Basically, laboratory analysis provides with
precise concentration values but takes longer time and higher costs than those of test-kit detection.
Furthermore, under the conditions that survey time and the total costs are restricted, test-kit detection
is more useful and practical as it can cover more inspection spots, resulting in precise information on the
pollution at investigation sites, compared with a conventional manner applying samples to laboratory
analysis that costs and limits the numbers of samples to be analysed due to a lean budget for financial
reasons.
The two investigation manners, or the conventional methods and the screening work, have their specific
advantages and characters. Then, it is quite natural to choose one of the two options. In short, one
gives precise concentration values at selected spots within a limited number but calling for high costs
while the other provides concentration levels at spots with no limits in number but showing good cost
performance.
This Technical Report describes the procedure to screen soil for Cr(VI) using a method with test-kits
developed for water samples.
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TECHNICAL REPORT ISO/TR 18105:2014(E)
Soil quality — Detection of water soluble chromium(VI)
using a ready-to-use test-kit method
1 Scope
This Technical Report describes the procedure to screen soil samples to detect Cr(VI) using test-kits
based on water extraction of Cr(VI) in soil. The test-kit approach in this method is designed to quickly
screen soil samples using calibration to indicate the concentration level. A batch test at a liquid to solid
ratio of 10 l/kg, designated by ISO/TS 21268-2, has been used in Japan for over 30 years to evaluate
the risk of Cr(VI) contamination in soil. The Cr(VI) detection by a ready-to-use test-kit method follows
ISO/TS 21268-2.
This screening technique is applicable in laboratories but can also be applied for site screening in the
field. The standard system detection covers the range mg/kg to % for Cr(VI).
This method is expected as a screening technique because of the significant colour change given by
1,5-diphenylcarbazide in the existence of Cr(VI). The method may be especially useful in quickly
detecting Cr(VI) where a site is assumed to have no Cr(VI) contamination. As with other screening
techniques, it is advisable to confirm a certain percentage of both positive and negative test results in
another technique, especially when the detected level is near or above a regulatory action limit or when
the presence of background or interfering materials is suspected.
Basically, laboratory analysis requires longer time and higher costs than those of test-kit detection. If the
same survey time and the costs are allowed with test-kit screening work and conventional investigation
methods including laboratory analysis, the former way can work on more inspection spots than the
latter. However, test-kit detection should carefully be adopted for site investigation because the recovery
of Cr(VI) from soil into water dependent on soil matrices changes the performance of test-kit detection.
2 References
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 11074, Soil quality — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11074 and the following apply.
3.1
ready-to-use method
analytical method that is ready-made for use, and may be employed in the field
Note 1 to entry: A more familiar name is “field method”.
[SOURCE: ISO 17381:2003, 3.2, modified — definition shortened]
4 Principle
Chromium(VI) in solution reacts with 1,5-diphenylcarbazide to form a red-violet complex of
chromium-1,5, diphenylcarbazone resulting in colour changes of the solution due to the formation.
Spectrometry and colour charts are applied to determine the complex. The test determines Cr(VI)
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ISO/TR 18105:2014(E)
present in the soil extract as chromate or dichromate ions. The test-kit method to detect the Cr(VI) in
soil consists of three basic steps: extraction, filtration and detection.
5 Reagents
5.1 Water, de-ionized, as an extraction solvent to extract Cr(VI) from soil samples.
5.2 Test-kit reagent, i.e. 1,5-diphenylcarbazide.
6 Interferences
Arsenic, cobalt, iron(II), iron(III), tin, vanadium, lead and phenol may give colour changes by reacting
with 1,5-diphenylcarbazide. Reducing agents like iron(II) and ascorbic acid effect to reduce Cr(VI) to
Cr(III). Thus, they also interfere with a chromium(VI)/1,5-diphenylcarbazone reaction.
7 Apparatus
7.1 Spectrometer, hand-held or portable photometer working at a wavelength of 540 nm.
7.2 Colour chart, with colour bars indicating a value on a reference concentration.
7.3 Spoon, non-metal to take soil samples.
7.4 Sample tube and vial, e.g. plastic or glass tube for the extraction operation by shaking and a
transparent glass vial for the test-kit observation.
8 Procedure
8.1 Calibration
When using a photometer for photometric observation of Cr(VI) in the sample solution, prepare a
calibration curve using blank and working standards. The working standards should be prepared by
spiking an appropriate amount of Cr(VI) solution into de-ionized water.
When using a colour chart for the detection of Cr(VI), the calibration process is not necessary.
8.2 Sample detection
Weigh out 1 g of a soil sample and put into 10 ml of water. Shake the mixture for 1 min and then filtrate
using a 0,45 μm pored membrane filter. Dilute 1 ml of the filtrate with water to give at least 10 ml, when
the colour of the sample is out of the range of the colour chart supplied by the manufacturer due to too
high concentration of Cr(VI) in the filtrate.
8.3 Measurement
Introduce a cer
...
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