ISO 14239:1997

Soil quality — Laboratory incubation systems for measuring the mineralization of organic chemicals in soil under aerobic conditions

Qualité du sol — Méthodes de mesure de la minéralisation de produits chimiques organiques dans le sol sous conditions aérobies, au moyen de systèmes d'incubation de laboratoire

Kakovost tal - Laboratorijski inkubacijski sistemi za merjenje mineralizacije organskih spojin v tleh pri aerobnih pogojih

General Information

• Status: Withdrawn
• Publication Date: 04-Jun-1997
• Withdrawal Date: 04-Jun-1997
• ICS: 13.080.30 - Biological properties of soils
• Technical Committee: ISO/TC 190/SC 4 - Biological characterization
• Drafting Committee: ISO/TC 190/SC 4 - Biological characterization
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 24-Jul-2017
• Ref Project: SIST ISO 14239:2001 - Soil quality -- Laboratory incubation systems for measuring the mineralization of organic chemicals in soil under aerobic conditions

Relations

• Revised: ISO 14239:2017 - Soil quality — Laboratory incubation systems for measuring the mineralization of organic chemicals in soil under aerobic conditions
• Effective Date: 04-Nov-2015

Standards Content (Sample)

INTERNATIONAL IS0
STANDARD 14239
First edition
1997-06-01
Soil quality - Laboratory incubation
systems for measuring the mineralization
of organic chemicals in soil under aerobic
conditions
- MBthodes de mesure de la minkalisation de produits chimiques
Qua/it6 du sol
organiques dans le sol sous conditions aerobics, au moyen de systhmes
d ’incubation de laboratoire
Reference number
IS0 14239: 1997(E)

---------------------- Page: 1 ----------------------
IS0 14239: 1997(E)
Contents Page
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Scope 1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~.~ 1
3 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
4 Calculation and expresssion of result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5 Test report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Annexes
A Approximate measurement of water-holding capacity of soil . . . . . . . . . . . . . . . 14
B Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
0 IS0 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Internet central @ iso.ch
x.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland
ii

---------------------- Page: 2 ----------------------
@ IS0
IS0 14239: 1997(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards bodies (IS0 member bodies). The work of preparing
International Standards is normally carried out through IS0 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
organizations, governmental and non-governmental, in liaison with ISO, also take
part in the work. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for voting. Publication as an International Standard requires
approval by at least 75 % of the member bodies casting a vote.
International Standard IS0 14239 was prepared by Technical Committee
ISO/TC 190, Soil quality, Subcommittee SC 4, Biological methods.
Annex A forms an integral part of this International Standard. Annex B is for
information only.

---------------------- Page: 3 ----------------------
IS0 14239: 1997(E) @ IS0
Introduction
This International Standard describes incubation systems for deter-
mining the mineralization of organic compounds in soil under
aerobic conditions.
Mineralization is only one of the parameters which can be used to
assess the biodegradation of organic compounds in soil. If miner-
alization is not extensive, this does not necessarily mean that the test
material is not biodegradable. Material balance studies to assess the
production of metabolites, in addition to mineralization studies,
provide a comprehensive assessment of biodegradation.
It is essential that this International Standard be used in conjunction
with IS0 11266, which gives general guidance on the information
needed to assess the potential of an organic compound to be
degraded in soil.
Depending on the aim of the study, it is feasible to use a range of
incubation conditions, described below, and different methods of
analysis.
NOTE - Several trade names of products are given as examples of
products available commercially. This information is given for the
convenience of users of this International Standard and does not constitute
an endorsement by IS0 of these products.
iv

---------------------- Page: 4 ----------------------
IS0 14239:1997(E)
INTERNATIONAL STANDARD @ IS0
Soil quality - Laboratory incubation systems for measuring the
mineralization of organic chemicals in soil under aerobic conditions
1 Scope
This International Standard specifies three incubation systems for measuring the rates and
extent of mineralization of organic compounds in soil by measurement of carbon dioxide
evolution. All three incubation systems are applicable to soluble or insoluble compounds but
choice of system depends on the overall purposes of the study.
This International Standard does not apply to the use of such systems for material balance
studies, which are often test-substance specific.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this International Standard. At the time of publication, the editions indicated
were valid. All standards are subject to revision, and parties agreements based on this
International Standard are encouraged to investigate the possibility of applying the most
recent editions of the standards indicated below. Members of IEC and IS0 maintain registers
of currently valid International Standards.
Guidance on the collection, handling and
IS0 10381-6:1993, Soil quality - Sampling -
storage of soil for the assessment of aerobic microbial processes in soil.
IS0 11266: 1994, Soil quality - Guidance on laboratory testing for biodegradation of organic
chemicals in soil.
IS0 11274:-l), Soil quality - Determination of the water retention characteristic - Laboratory
methods.
3 Methods
31 . General requirements
The following procedures shall be followed, whichever incubation system is selected.
Soil collection and characterization
3.1.1
Soil shall be collected and handled in accordance with IS0 1038 l-6. The soil shall be
characterized in accordance with IS0 11266: 1994, 5.1.1.
‘) To be published.

---------------------- Page: 5 ----------------------
IS0 14239: 1997(E)
3.1.2 Test material
The test material shall be characterized in accordance with IS0 11266: 1994, 5.2.
Incubation conditions
3.1.3
The following conditions shall be used unless there is a specific reason for using different
conditions:
(20 + 2)OC
Temperature:
-
Pore water pressure of soil: -0,Ol MPa to -0,03 MPa (measured to * 5%)
as determined .in accordance with IS0 11274
[or between 40% and 60% max. FVHC (measured
to + 5%) in accordance with Annex A.]
Incubation: in the dark
The incubation conditions should be reported in the test report. If they differ from those
above, the reasons for changing them should also be reported in the test report.
A temperature of (20 + 2) ‘C has been chosen as a standard for comparative purposes and
because it gives relatively rapid results. Temperatures outside this range can be used if they
are more appropriate (for example, because of local conditions, lack of cooling equipment).
32 0 Choice of incubation systems
One of the three systems described in this International Standard, the flow-through system
(3.3), the soda-lime column system (3.4) or the biometer system (3.5), shall be used.
Data on the mineralization of organic chemicals can most reliably be obtained from
experiments with radiolabelled compounds. Where unlabelled organic chemicals are used, a
number of controls are necessary and carbon dioxide evaluation data should be analysed
statistically.
Recoveries of carbon dioxide (CO2) in the three systems can be measured using known
quantities of unlabelled or “C-labelled calcium carbonate and adding sufficient hydrochloric
acid to dissolve fully the calcium carbonate.
WARNING The methods in this International Standard use several materials of a
hazardous nature. Due care is necessary in their handling and disposal. In particular,
all pertinent national regulations should be complied with.
The main advantages and disadvantages of the systems are:
a) Flow-through system:
The main advantages are: sufficient oxygen for long-term, aerobic degradation
studies; uses standard laboratory glassware; allows measurement of unlabelled CO2
14C02 (scintillation counting), and/or
(titration), “C-labelled volatile products
(scintillation counting).

---------------------- Page: 6 ----------------------
IS0 14239:1997(E)
@ IS0
The main disadvantages are: difficulties with complete recoveries when volatile
14C-compounds are under investigation; sensitivity to leaks in the system.
b) Soda lime column system:
The main advantages are: free access of oxygen for long-term degradation studies;
uses standard laboratory glassware; requires little space; adaptable without changes
for use with standing or shaken aerobic sediments, pure cultures of microorganisms,
algae or plant cell cultures; problem-free incubation under various environmental
conditions; full recoveries of applied radioactivity in short- or long-term material
balance studies.
The main disadvantages are: 14C02 trapped in soda lime has to be released and
re-adsorbed in liquid for scintillation counting; water content of soils has to be
adjusted at least once per month.
c) Biometer system
The main advantages are: requires little space; adaptable Without changes for use
with standing cultures of aerobic sediments, pure cultures of microorganisms or
algae; problem-free incubation under various environmental conditions; ease of
measurement of non-radioactive CO2 (titration), 14C02 (scintillation counting or
“C-labelled volatile products (scintillation counting).
The main disadvantages are: not ideal for long-term incubations due to lack of free
access of air and reduction of partial pressure of oxygen in chamber during
incubation; requires special glassware.
33 . Flow-through system
3.3.1 Principle
This method allows determination of the dissipation and/or metabolism of non-radioactive or
“C-labelled test materials in soil. C02-free air is drawn through the incubation vessel
containing the treated soil samples. The CO2 and organic volatiles evolved from the soil are
trapped in a series of absorption traps.
3.3.2 Materials and reagents
Reagents of recognized analytical grade shall be used.
3.3.2.1 Source of COz-free air (e.g. obtained by passing air through an aqueous solution of
strong alkali). For studies with “C-labelled compounds, CO2 need not be
removed from the air unless there is a danger of saturation of the CO2 traps.
3.3.2.2 Ethylene glycol or ethylene glycol methyl ester, for absorption of organic
volatiles.
3.3.2.3 Polyurethane foam trap, density 16 kg/m3 for absorption of organic volatiles. .
3.3.2.4 Sulfuric acid, c(H2SO4 ) = 0,5 mol/l, for absorption of alkaline volatiles.
3.3.2.5 Sodium or potassium hydroxide solution, c&OH) [or (NaOH)] = 0,l mol/l to
O,5 mol/l for absorption of nonradioactive CO 2; or scintillation cocktail for absorption of
‘4co 1)
2 l
1) Carbosorb (Canberra Packard) and Oxisolve (Zinsser) are examples of suitable products available commercially This
information is given for the convenience of users of this International Standard and does not constitute an endorsement by
IS0 of these products.

---------------------- Page: 7 ----------------------
IS0 14239:1997(E)
WARNING If the scintillation cocktail is used as a trap, volatile organic
amines and ,solvents can accumulate in toxic concentrations and there is
danger of explosion. Therefore it is essential that the work area is well
ventilated.
3.3.2.6 Scintillation cocktails for determination of the 14C02 in alkali traps?
3.3.3 Apparatus and glassware
3.3.3.1 Liquid scintillation counter
3.3.3.2 Scintillation vials
Temperature-controlled incubator or room (If: 2 ’C)
3.3.3.3
3.3.3.4 Membrane pump (capacity, approximately 2,8 m3/h)
3.3.3.5 Flow meter
3.3.3.6 Flow-restrictor valves
3.3.3.7 Glass dishes for system I, e.g. moist soil (equivalent to 50 g dry mass)
- diameter 5 cm, height 5 cm - for samples equivalent to 50 g air-dried soil
- diameter 9,5 cm, height 5 cm - for samples equivalent to 300 g air-dried soil
3.3.3.8 Erlenmeyer flask (250 ml) for system II
3.3.3.9 Gas washing bottles (100 ml) for absorption traps
3.3.3.10 Gas washing bottles (200 ml to 500 ml ) for moistening the air.
3.3.4 Procedure
Choose incubation system I or II described below. System I is more applicable when many
samples have to be incubated in limited space, system II requires more space but is applicable
for small-scale experiments.
3.3.4.1 Incubation system I
Incubation of soil samples shall take place in temperature-controlled incubators or rooms
(3.3.3.3.). Set up cylindrical, separately removable incubation units in the chamber (see
Figure 1). The incubation units shall contain sets of soil samples in glass dishes (3.3.3.7)
(normally one incubation set consists of 6 sub-samples). Each incubation unit can be aerated
separately.
In order to ensure aerobic conditions, draw a constant stream of C02-free air (3.3.2.1)
through each incubation unit using a membrane pump (3.3.3.4).
3.3.4.2 Incubation system II
Incubate the soil sample in a glass flask (e.g. Erlenmeyer flask) (3.3.3.8) in a temperature-
controlled room or incubator (3.3.3.3). Draw a constant stream of COZ-free air (3.3.2.1)
through the flask.
1) Hionic fluor and Optifluor (Canberra Packard) are examples of suitable products available commercially. This
information is given for the convenience of users of this International Standard and does not constitute an
endorsement by IS0 of these products.
4

---------------------- Page: 8 ----------------------
IS0 14239:1997(E)
@ IS0
3.3.4.3 Absorption of volatile products
For both systems, moisten the C02-free air passing over the soils by bubbling it through
half-filled with acidified, deionized water
2 gas wash bottles (3.3.3.1) about
(approximately 1 ml of concentrated sulfuric acid per litre of water). Distribute the water-
saturated air to the different incubation units via valves (3.3.3.6).
Establish a constant flow of approximately 0,l l/min through each incubation unit; use a
flow meter (3.3.3.5) to measure the flow rates.
For both systems, bubble the outgoing gas through an absorption system to capture
volatilized parent compound, volatile metabolite, and CO2 for subsequent analyses. All
connections shall be made of stainless steel or polytetrafluoroethylene (PTFE) tubing.
Quantify any 14C-labelled compounds by liquid scintillation counting, as appropriate.
The absorption systems consist of:
- one gas washing bottle (3.3.3.9) filled with reagent for absorption of organic volatiles
(3.3.2.2 or 3.3.2.3);
- one gas washing bottle (3.3.3.9) filled with reagent for absorption of alkaline
volatiles (3.3.2.4) (if necessary);
- one gas washing bottle for absorption of CO2 (3.3.2.5). If high rates of
CO2Gproduction are expected, a second CO2 trap is needed.
Flow-through monitor
Valve for maintaining a slight pressure
\
+C Gas supply
1
Reskvoir
Wash bottles
Incubation unit
7
I L rl-
Va Ive
L Sample
IAl- 1 Distribution board
\
Incubation chamber
Valve for flow-through regu
...

SLOVENSKI STANDARD
SIST ISO 14239:2001
01-september-2001
Kakovost tal - Laboratorijski inkubacijski sistemi za merjenje mineralizacije
organskih spojin v tleh pri aerobnih pogojih
Soil quality -- Laboratory incubation systems for measuring the mineralization of organic
chemicals in soil under aerobic conditions
Qualité du sol -- Méthodes de mesure de la minéralisation de produits chimiques
organiques dans le sol sous conditions aérobies, au moyen de systèmes d'incubation de
laboratoire
Ta slovenski standard je istoveten z: ISO 14239:1997
ICS:
13.080.10 .HPLMVNH]QDþLOQRVWLWDO Chemical characteristics of
soils
SIST ISO 14239:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ISO 14239:2001

---------------------- Page: 2 ----------------------

SIST ISO 14239:2001
INTERNATIONAL IS0
STANDARD 14239
First edition
1997-06-01
Soil quality - Laboratory incubation
systems for measuring the mineralization
of organic chemicals in soil under aerobic
conditions
- MBthodes de mesure de la minkalisation de produits chimiques
Qua/it6 du sol
organiques dans le sol sous conditions aerobics, au moyen de systhmes
d ’incubation de laboratoire
Reference number
IS0 14239: 1997(E)

---------------------- Page: 3 ----------------------

SIST ISO 14239:2001
IS0 14239: 1997(E)
Contents Page
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Scope 1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~.~ 1
3 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
4 Calculation and expresssion of result . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5 Test report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Annexes
A Approximate measurement of water-holding capacity of soil . . . . . . . . . . . . . . . 14
B Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
0 IS0 1997
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 l CH-1211 Geneve 20 l Switzerland
Internet central @ iso.ch
x.400 c=ch; a=400net; p=iso; o=isocs; s=central
Printed in Switzerland
ii

---------------------- Page: 4 ----------------------

SIST ISO 14239:2001
@ IS0
IS0 14239: 1997(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards bodies (IS0 member bodies). The work of preparing
International Standards is normally carried out through IS0 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
organizations, governmental and non-governmental, in liaison with ISO, also take
part in the work. IS0 collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for voting. Publication as an International Standard requires
approval by at least 75 % of the member bodies casting a vote.
International Standard IS0 14239 was prepared by Technical Committee
ISO/TC 190, Soil quality, Subcommittee SC 4, Biological methods.
Annex A forms an integral part of this International Standard. Annex B is for
information only.

---------------------- Page: 5 ----------------------

SIST ISO 14239:2001
IS0 14239: 1997(E) @ IS0
Introduction
This International Standard describes incubation systems for deter-
mining the mineralization of organic compounds in soil under
aerobic conditions.
Mineralization is only one of the parameters which can be used to
assess the biodegradation of organic compounds in soil. If miner-
alization is not extensive, this does not necessarily mean that the test
material is not biodegradable. Material balance studies to assess the
production of metabolites, in addition to mineralization studies,
provide a comprehensive assessment of biodegradation.
It is essential that this International Standard be used in conjunction
with IS0 11266, which gives general guidance on the information
needed to assess the potential of an organic compound to be
degraded in soil.
Depending on the aim of the study, it is feasible to use a range of
incubation conditions, described below, and different methods of
analysis.
NOTE - Several trade names of products are given as examples of
products available commercially. This information is given for the
convenience of users of this International Standard and does not constitute
an endorsement by IS0 of these products.
iv

---------------------- Page: 6 ----------------------

SIST ISO 14239:2001
IS0 14239:1997(E)
INTERNATIONAL STANDARD @ IS0
Soil quality - Laboratory incubation systems for measuring the
mineralization of organic chemicals in soil under aerobic conditions
1 Scope
This International Standard specifies three incubation systems for measuring the rates and
extent of mineralization of organic compounds in soil by measurement of carbon dioxide
evolution. All three incubation systems are applicable to soluble or insoluble compounds but
choice of system depends on the overall purposes of the study.
This International Standard does not apply to the use of such systems for material balance
studies, which are often test-substance specific.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute
provisions of this International Standard. At the time of publication, the editions indicated
were valid. All standards are subject to revision, and parties agreements based on this
International Standard are encouraged to investigate the possibility of applying the most
recent editions of the standards indicated below. Members of IEC and IS0 maintain registers
of currently valid International Standards.
Guidance on the collection, handling and
IS0 10381-6:1993, Soil quality - Sampling -
storage of soil for the assessment of aerobic microbial processes in soil.
IS0 11266: 1994, Soil quality - Guidance on laboratory testing for biodegradation of organic
chemicals in soil.
IS0 11274:-l), Soil quality - Determination of the water retention characteristic - Laboratory
methods.
3 Methods
31 . General requirements
The following procedures shall be followed, whichever incubation system is selected.
Soil collection and characterization
3.1.1
Soil shall be collected and handled in accordance with IS0 1038 l-6. The soil shall be
characterized in accordance with IS0 11266: 1994, 5.1.1.
‘) To be published.

---------------------- Page: 7 ----------------------

SIST ISO 14239:2001
IS0 14239: 1997(E)
3.1.2 Test material
The test material shall be characterized in accordance with IS0 11266: 1994, 5.2.
Incubation conditions
3.1.3
The following conditions shall be used unless there is a specific reason for using different
conditions:
(20 + 2)OC
Temperature:
-
Pore water pressure of soil: -0,Ol MPa to -0,03 MPa (measured to * 5%)
as determined .in accordance with IS0 11274
[or between 40% and 60% max. FVHC (measured
to + 5%) in accordance with Annex A.]
Incubation: in the dark
The incubation conditions should be reported in the test report. If they differ from those
above, the reasons for changing them should also be reported in the test report.
A temperature of (20 + 2) ‘C has been chosen as a standard for comparative purposes and
because it gives relatively rapid results. Temperatures outside this range can be used if they
are more appropriate (for example, because of local conditions, lack of cooling equipment).
32 0 Choice of incubation systems
One of the three systems described in this International Standard, the flow-through system
(3.3), the soda-lime column system (3.4) or the biometer system (3.5), shall be used.
Data on the mineralization of organic chemicals can most reliably be obtained from
experiments with radiolabelled compounds. Where unlabelled organic chemicals are used, a
number of controls are necessary and carbon dioxide evaluation data should be analysed
statistically.
Recoveries of carbon dioxide (CO2) in the three systems can be measured using known
quantities of unlabelled or “C-labelled calcium carbonate and adding sufficient hydrochloric
acid to dissolve fully the calcium carbonate.
WARNING The methods in this International Standard use several materials of a
hazardous nature. Due care is necessary in their handling and disposal. In particular,
all pertinent national regulations should be complied with.
The main advantages and disadvantages of the systems are:
a) Flow-through system:
The main advantages are: sufficient oxygen for long-term, aerobic degradation
studies; uses standard laboratory glassware; allows measurement of unlabelled CO2
14C02 (scintillation counting), and/or
(titration), “C-labelled volatile products
(scintillation counting).

---------------------- Page: 8 ----------------------

SIST ISO 14239:2001
IS0 14239:1997(E)
@ IS0
The main disadvantages are: difficulties with complete recoveries when volatile
14C-compounds are under investigation; sensitivity to leaks in the system.
b) Soda lime column system:
The main advantages are: free access of oxygen for long-term degradation studies;
uses standard laboratory glassware; requires little space; adaptable without changes
for use with standing or shaken aerobic sediments, pure cultures of microorganisms,
algae or plant cell cultures; problem-free incubation under various environmental
conditions; full recoveries of applied radioactivity in short- or long-term material
balance studies.
The main disadvantages are: 14C02 trapped in soda lime has to be released and
re-adsorbed in liquid for scintillation counting; water content of soils has to be
adjusted at least once per month.
c) Biometer system
The main advantages are: requires little space; adaptable Without changes for use
with standing cultures of aerobic sediments, pure cultures of microorganisms or
algae; problem-free incubation under various environmental conditions; ease of
measurement of non-radioactive CO2 (titration), 14C02 (scintillation counting or
“C-labelled volatile products (scintillation counting).
The main disadvantages are: not ideal for long-term incubations due to lack of free
access of air and reduction of partial pressure of oxygen in chamber during
incubation; requires special glassware.
33 . Flow-through system
3.3.1 Principle
This method allows determination of the dissipation and/or metabolism of non-radioactive or
“C-labelled test materials in soil. C02-free air is drawn through the incubation vessel
containing the treated soil samples. The CO2 and organic volatiles evolved from the soil are
trapped in a series of absorption traps.
3.3.2 Materials and reagents
Reagents of recognized analytical grade shall be used.
3.3.2.1 Source of COz-free air (e.g. obtained by passing air through an aqueous solution of
strong alkali). For studies with “C-labelled compounds, CO2 need not be
removed from the air unless there is a danger of saturation of the CO2 traps.
3.3.2.2 Ethylene glycol or ethylene glycol methyl ester, for absorption of organic
volatiles.
3.3.2.3 Polyurethane foam trap, density 16 kg/m3 for absorption of organic volatiles. .
3.3.2.4 Sulfuric acid, c(H2SO4 ) = 0,5 mol/l, for absorption of alkaline volatiles.
3.3.2.5 Sodium or potassium hydroxide solution, c&OH) [or (NaOH)] = 0,l mol/l to
O,5 mol/l for absorption of nonradioactive CO 2; or scintillation cocktail for absorption of
‘4co 1)
2 l
1) Carbosorb (Canberra Packard) and Oxisolve (Zinsser) are examples of suitable products available commercially This
information is given for the convenience of users of this International Standard and does not constitute an endorsement by
IS0 of these products.

---------------------- Page: 9 ----------------------

SIST ISO 14239:2001
IS0 14239:1997(E)
WARNING If the scintillation cocktail is used as a trap, volatile organic
amines and ,solvents can accumulate in toxic concentrations and there is
danger of explosion. Therefore it is essential that the work area is well
ventilated.
3.3.2.6 Scintillation cocktails for determination of the 14C02 in alkali traps?
3.3.3 Apparatus and glassware
3.3.3.1 Liquid scintillation counter
3.3.3.2 Scintillation vials
Temperature-controlled incubator or room (If: 2 ’C)
3.3.3.3
3.3.3.4 Membrane pump (capacity, approximately 2,8 m3/h)
3.3.3.5 Flow meter
3.3.3.6 Flow-restrictor valves
3.3.3.7 Glass dishes for system I, e.g. moist soil (equivalent to 50 g dry mass)
- diameter 5 cm, height 5 cm - for samples equivalent to 50 g air-dried soil
- diameter 9,5 cm, height 5 cm - for samples equivalent to 300 g air-dried soil
3.3.3.8 Erlenmeyer flask (250 ml) for system II
3.3.3.9 Gas washing bottles (100 ml) for absorption traps
3.3.3.10 Gas washing bottles (200 ml to 500 ml ) for moistening the air.
3.3.4 Procedure
Choose incubation system I or II described below. System I is more applicable when many
samples have to be incubated in limited space, system II requires more space but is applicable
for small-scale experiments.
3.3.4.1 Incubation system I
Incubation of soil samples shall take place in temperature-controlled incubators or rooms
(3.3.3.3.). Set up cylindrical, separately removable incubation units in the chamber (see
Figure 1). The incubation units shall contain sets of soil samples in glass dishes (3.3.3.7)
(normally one incubation set consists of 6 sub-samples). Each incubation unit can be aerated
separately.
In order to ensure aerobic conditions, draw a constant stream of C02-free air (3.3.2.1)
through each incubation unit using a membrane pump (3.3.3.4).
3.3.4.2 Incubation system II
Incubate the soil sample in a glass flask (e.g. Erlenmeyer flask) (3.3.3.8) in a temperature-
controlled room or incubator (3.3.3.3). Draw a constant stream of COZ-free air (3.3.2.1)
through the flask.
1) Hionic fluor and Optifluor (Canberra Packard) are examples of suitable products available commercially. This
information is given for the convenience of users of this International Standard and does not constitute an
endorsement by IS0 of these products.
4

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SIST ISO 14239:2001
IS0 14239:1997(E)
@ IS0
3.3.4.3 Absorption of volatile products
For both systems, moisten the C02-free air passing over the soils by bubbling it through
half-filled with acidified, deionized water
2 gas wash bottles (3.3.3.1) about
(approximately 1 ml of concentrated sulfuric acid per litre of water). Distribute the water-
saturated air to the different incubation units via valves (3.3.3.6).
Establish a constant flow of approximately 0,l l/min through each incubation unit; use a
flow meter (3.3.3.5) to measure the flow rates.
For both systems, bubble the outgoing gas through an absorption system to capture
volatilized parent compound, volatile metabolite, and CO2 for subsequent analyses. All
connections shall be made of stainless steel or polytetrafluoroethylene (PTFE) tubing.
Quantify any 14C-labelled compounds by liquid s
...