CEN/TR 14589:2003

SLOVENSKI STANDARD
01-maj-2004
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Characterization of waste - State of the art document - Chromium VI specification in solid
matrices
Charakterisierung von Abfällen - Bestimmung von Chrom in AbfallStatusbericht
Caractérisation des déchets - Etat de l'art - Spécification du Chrome (VI) dans les
matrices solides
Ta slovenski standard je istoveten z: CEN/TR 14589:2003
ICS:
13.030.10 Trdni odpadki Solid wastes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 14589
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
May 2003
ICS 13.030.10
English version
Characterization of waste – State of the art document –
Chromium VI specification in solid matrices
Caractérisation des déchets - Etat de l'art - Spécification Charakterisierung von Abfällen - Bestimmung von Chrom in
pour la détermination du Chrome VI dans les matrices AbfallStatusbericht
solides
This Technical Report was approved by CEN on 7 April 2003. It has been drawn up by the Technical Committee CEN/TC 292.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 14589:2003 E
worldwide for CEN national Members.

Contents
Foreword. 3
Introduction . 3
1 Scope . 3
2 Normative references . 4
3 Symbols and abbreviations. 4
4 Chromium VI speciation in solid matrices . 6
5 Final conclusions. 19
Bibliography . 38
Foreword
This document (CEN/TR 14589) has been prepared by Technical Committee CEN/TC 292 "Characterization of
waste", the secretariat of which is held by NEN.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,
Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Introduction
Speciation is one of the growing features of analytical chemistry of the last years. It is now recognized that the
determination of total trace element contents is no longer sufficient, because the biological and environmental
impact of an element is dictated by the physico-chemical form in which it is present in the sample.
Chromium belongs to the category of problematic elements in analytical chemistry, because it behaves as a
valence chameleon. The chemistry of chromium compounds is rather complicated, inorganic chromium compounds
may occur in oxidation states ranging from -II to +VI [1,2]. However, in natural systems, Cr(III) and Cr(VI) are the
most stable forms. Besides Cr(III) which is an essential trace element for mammals, including man, Cr(VI)
compounds are genotoxic and potentially carcinogenic in humans. Evidence exists for the carcinogenity of calcium,
strontium and zinc chromate [2,3]. The inoffensive nature of Cr(III) ions results from the fact that in biotic
n-3
environment, it usually appears in aqua-hydroxo complexes of the form []Cr()H O (OH ) and their size
2 6-n
n
excludes them almost entirely from penetrating cell membranes [4].
From chemical point of view, Cr(III) shows similarities with that of Al O : Cr O is amfoteric, albeit more basic than
2 3 2 3
acidic. In contrast, Cr(VI) is strongly acidic; all Cr(VI) compounds, except for CrF are oxocompounds:
-2-2-
HCrO CrO Cr O
(hydrochromate), (chromate) and (dichromate) species which are powerful oxidants.
4 4 2 7
Under environmental conditions, dichromates are not formed at a total chromium concentration less than
0,01 mol/l. Certain forms of Cr(III) may oxidize to Cr(VI) in soils and that Cr(VI) may be reduced to Cr(III) in the
same soil. Since under alkaline to slightly acidic conditions, Cr(VI) compounds are not strongly absorbed by many
soils, they can be very mobile in surface environments. On the other hand, under these conditions, Cr(III) readily
precipitates as Cr(OH) . Cr(VI) can be reduced to Cr(III) in soils by redox reactions with aqueous inorganic species,
electron transfer at mineral surfaces, reactions with non-humic organic substances such as carbohydrates and
proteins or reduction by soil humic substances [5]. The latter, which constitutes the majority of the organic fraction
in most soils, represents a significant reservoir of electron donors for Cr(VI) reduction. As a result, the opposing
solubility and toxicity characteristic of Cr(III) and Cr(VI) and the potential for Cr(III) oxidation in soil represent a
unique regulatory challenge for the establishment of protective, health-based clean-up standards for Cr-
contaminated soils [6]. Remediation of Cr(VI) containing soils through reduction to Cr(III) will lower the health and
ecological hazard of such soils.
As a consequence of previous considerations, most attention is paid to Cr(VI) determination in environmental
matter. Unfortunately, just this task is difficult to handle. Intricacies are primarily because of instability of the
oxidation states of chromium and the complex character of environmental samples.
1 Scope
This European document describes the state-of-the-art extraction and determination methods for the total content
of hexavalent chromium in raw waste and other solid materials.
2 Normative references
This document incorporates by dated or undated reference, provisions from other publications. These normative
references are cited at the appropriate places in the text and the publications are listed hereafter. For dated
references, subsequent amendments to or revisions of any of these publications apply to this document only when
incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).;
AS 2882 : 1986 Waters-Determination of chromium (VI)(diphenylcarbazide spectrophotometric
(Australia): method);
Test Method for Dissolved Hexavalent Chromium in Water by Ion Chromatography;
ASTM D 5257 1997
ASTM D 5281: 1998 Standard Test Method for Collection and Analysis of Hexavalent Chromium in
Ambient Atmospheres;
DSF 38929: 1999 Packaging-Requirement for measuring and verifying four heavy metals and other
dangerous substances present in packaging and their release into the environment-
Part 1: Requirements for measuring and verifying four metals present in packaging
(lead, cadmium, chromium VI and mercury);
IRSA (Italy): 1986 Analytical Methods for Waste-Physico-Chemical Parameters, Method No. 16,
Hexavalent Chromium
(colorimetric reaction with diphenylcarbazide);
ISO 11083: 1994 Water quality-Photometric determination of Chromium VI with 1.5 diphenylcarbazide;
ISO 3856-5: 1984 Determination of hexavalent chromium content of pigment portion of liquid paint or
paint in powder form-spectrophotometric method with diphenylcarbazide;
Soil quality-Determination of Chromium (VI) in phosphate extract;
DIN 19734: 1999
DIN 38405-24: 1987 German standard methods for the examination of water, waste water and sludge;
photometric determination of Chromium (VI) using 1.5 DPC
;
DIN 53780: 1999 Pigments and extenders-Determination of matter soluble in water-hexavalent
chromium content
3 Symbols and abbreviations
For the purposes of this documentError! No text of specified style in document., the following symbols and
abbreviations apply:
50 52
III
is the mass bias corrected measured isotope ratio of Cr to Cr of Cr(III) in the spiked sample;
R
50/52
is the atomic fraction of Cr in the sample;
A
x
III
is the concentration of Cr(III) in the sample (μmol/g, unknown);
C
x
50 50
50 III
is the atomic fraction of Cr in the Cr(III) spike;
A
s
III
is the concentration of Cr(III) in the Cr(III) spike (μmol/g);
C
s
VI
is the concentration of Cr(VI) in the Cr(VI) spike (μmol/g);
C
s
III
is the weight of the Cr(III) spike (g);
W
s
VI
is the concentration of Cr(VI) in the sample (μmol/g, unknown);
C
x
B is the bias per mass unit;
c , c is the concentration of analysed sample and spike, respectively (μg/g);
x s
I is the true number of counts, that means the number of counts that would have been detected if
there had been not dead time;
I is the number of counts measured on a channel;
m
K is the mass discrimination factor;
M , M is the atomic mass of isotope "1" and "2", respectively;
1 2
M , M is the atomic mass of analysed sample and spike, respectively (μg/mol);
x s
N is the number of atoms;
i
N , N is the total number of atoms in unknown sample and spike, respectively;
x s
R is the real isotope ratio;
R' is the measured isotope ratio;
R , R is the corrected-isotope ratio and the measured dead-time-corrected isotope ratios of the sample,
c m
respectively;
R , R is the certified isotope ratio and the measured isotope ratios of the standard material (dead time
t m
corrected);
W , W is the weigh of unknown sample and spike, respectively (g);
x s

is the percentage of Cr(III) oxidized to Cr(VI) after spiking (unknown);
 is the percentage of Cr(VI) reduced to Cr(III) after spiking (unknown);

is the dead time;
Aliquat-336: methyltricaprylammonium;
APDC: ammonium pyrolidine dithiocarbamate;
DDTC: diethyldithiocarbamate;
DIN
: direct injection nebulization;
DPC: Diphenylcarbazide;
DPP: differential pulse polarography;
DPTA: Diethylenetriaminepentaacetic;
HHPN
: hydraulic high-pressure nebulization;
HMDE: hanging mercury drop electrode;
HPLC:
high pressure liquid-chromatography;
IC: ion-chromatography;
IC-DPC: ion chromatography diphenylcarbazide;
IC-ICP-MS: ion chromatography inductively coupled plasma mass spectrometry;
ICP-MS:
inductively coupled plasma-mass spectrometry;
ID: Isotope Dilution method;
LC: liquid-chromatography;
LiFDDC: lithium bis(trifluoroethyl) dithiocarbamate;
LL
: Liquid-liquid extraction;
MIBK: methyl isobuthyl ketone;
NPP: normal pulse polarography;
ORP: Oxidation Reduction Potential;
SFE
: Supercritical fluid extraction;
SIDMS: Speciation Isotope Dilution-Mass Spectrometry;
TBDTC: dibuthyl-dithiocarbamate;
TOC: Total Organic Carbon;
TSN
: thermospray nebulization;
4 Chromium VI speciation in solid matrices
4.1 Chromium VI extraction from solid matrices
4.1.1 Sample pre-treatment
To quantify total Cr(VI) in solid matrices, three criteria must be satisfied:
a) the extraction solution must solubilize all forms of Cr(VI);
b) the conditions of the extraction must not induce reduction of native Cr(VI) to Cr(III);
c) the method must not cause oxidation of native Cr(III) contained in the sample.
Thus, it has been recognized that Cr(VI) must be leached from samples in an alkaline medium rather than in acidic
medium in order to inhibit Cr(VI) to Cr(III) reduction by possible reductants present in sample [2]. An alkaline
extraction procedure, USEPA SW-846 Method 3060 for the preparation of soil samples in view of analysis of total
Cr(VI) was used for a number of years. But an USEPA funded research study did not achieved consistent results
among samples using this method [7]. The researches concluded that the Cr oxidation state is matrix specific and
may be unstable and unpredictable (in environmental samples) once it is solubilize in either an acidic or basic
aqueous extraction medium [8]. Based on these considerations, in June 1997 the USEPA promulgated SW-846
rd
Method 3060A for inclusion in the Third Update to the Test Method for Evaluating Solid Waste, SW-846, 3 ed. [5].
Although the basic chemistry has remained the same, the modifications to USEPA SW-846 Method 3060 have
enhanced the efficiency of the extraction process, principally by reducing the soil sample weight and decreasing the
ratio of sample weight to alkaline digest volume.
4.1.2 USEPA SW-846 Method 3060A [9]
4.1.2.1 Summary of USEPA SW-846 Method 3060A
The solid sample is digested using a mixed solution (pH>11,5) consisting of Na CO (0,28 M) and NaOH (0,5 M)
2 3
and heating at 90 °C – 95 °C for 60 minutes, in order to dissolve the Cr(VI) and stabilize it against reduction to
Cr(III)
For waste materials or soils containing soluble Cr(III) greater than four times the laboratory Cr(VI) detection limit,
Cr(VI) results obtained using this method may be high biased because of method-induced oxidation. Thus the
method recommends the addition of Mg(II) in a phosphate buffer to the alkaline extraction solution to suppress this
oxidation. When analysing a sample digest for total Cr(VI) it is appropriate to determine the reducing/oxidizing
tendency of each sample matrix. This can be accomplished by characterization of each
...