prEN 16175-1

• Abstract:

  This European Standard specifies a method for the determination of mercury in digests of soil, treated biowaste and waste, obtained according to EN ISO 54321 (aqua regia digestion) or EN 16173 (nitric acid digestion) or EN 13656 (digestion with a hydrochloric, nitric and tetrafluoroboric or hydrofluoric acid mixture) using cold-vapour atomic absorption spectrometry (CV-AAS). The lower working range limit is at least 0,03 mg/kg (drymatter basis) depending on digestion parameters.

• Status: Not Published
• Publication Date: 16-May-2028
• ICS: 13.080.01 - Soil quality and pedology in general
• ICS: 13.080.10 - Chemical characteristics of soils
• Technical Committee: CEN/TC 444 - Environmental characterization
• Drafting Committee: CEN/TC 444/WG 3 - Inorganic analysis
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 03-Sep-2026
• Due Date: 03-Feb-2027
• Completion Date: 03-Sep-2026
• Ref Project: oSIST prEN 16175-1:2026 - Soil, treated biowaste and sludge - Determination of mercury - Part 1: Cold-vapour atomic absorption spectrometry (CV-AAS)

• Revises: EN 16175-1:2016 - Sludge, treated biowaste and soil - Determination of mercury - Part 1: Cold-vapour atomic absorption spectrometry (CV-AAS)
• Effective Date: 18-Mar-2026

prEN 16175-1 is a CEN draft European Standard for determining mercury in digests of soil, treated biowaste, sludge and waste by cold-vapour atomic absorption spectrometry (CV-AAS). It specifies a laboratory method for trace-level measurement in digests prepared by EN 16173, EN ISO 54321 or EN 13656. The lower working range limit is at least 0.03 mg/kg on a dry matter basis, depending on digestion parameters.

What does prEN 16175-1 specify?

prEN 16175-1 specifies a CV-AAS method for mercury in digests of environmental solid matrices. It is organized as clauses on scope, principle, interferences, reagents, apparatus, procedure, calculation, performance data and test report, plus informative Annex A on precision data.

The scope is focused on digests already prepared by approved digestion routes. In practice, that means the document does not describe the digestion itself in detail, but the measurement step after digestion.

• Clause 1 - scope and working range
• Clause 4 - measurement principle
• Clause 5 - matrix interferences
• Clauses 6 to 8 - reagents, apparatus and procedure
• Clause 9 - calculation and expression of results
• Clause 10 - performance data
• Clause 11 - test report
• Annex A - repeatability and reproducibility data

What are the key requirements of prEN 16175-1?

prEN 16175-1 requires the analyst to measure mercury after reduction to elemental mercury and separation in a closed system. The method uses the absorbance of mercury vapour at 253.7 nm and calculates concentration from a calibration curve.

Measurement principle and reduction chemistry

Clause 4 states that mono- and divalent mercury are reduced to the elemental form with tin(II) chloride or sodium borohydride in acid medium. Tin(II) chloride is recommended because sodium borohydride can reduce many other elements and create matrix problems. In practice, this means laboratories should prefer the less interfering reducer unless their system is validated with sodium borohydride.

Control of interferences

Clause 5 explains that the acidic digestion removes organic interferences in the gas phase, but other matrix elements can still bias the result if their concentration is too high. The clause gives tolerable concentrations for some elements such as Cu(II), Ni(II) and Ag(I). This matters because analysts may need to dilute or recheck a digest if the matrix is unusually heavy in metals.

Reagents and solution quality

Clause 6 requires reagents of trace-analysis quality, including high-purity water and carrier gas. It also specifies the preparation of the reducing solutions, mercury stock solution and stabilized mercury standards. In practice, reagent purity and freshness matter because contamination at the same level as the analyte can distort low-level mercury results.

Apparatus and system configuration

Clause 7 allows usual laboratory glassware and either manual, semi-automated or automated systems. The method describes the use of an atomic absorption spectrometer, a cold-vapour generator and, for automated systems, flow injection analysis (FIA). This matters because the chosen setup affects sensitivity, reaction time and the working range.

Calibration and measurement sequence

Clause 8 requires a blank calibration solution and at least five calibration solutions prepared with the same reagent proportions as the test solutions. The test blank is prepared alongside the sample and used for correction. Practically, this means the lab must match the chemistry of standards, blanks and samples as closely as possible to avoid bias.

Calculation and reporting

Clause 9 gives the calculation of mercury content in solid samples, corrected to dry matter, and states that results should be reported with no more than three significant figures. The calculation uses the measured test solution, the test blank, dilution factor, digest volume, sample mass and dry matter fraction. This makes dry-matter determination part of the final reported value, not just an optional extra.

Performance and reporting records

Clause 10 points to Annex A for performance data, and Clause 11 lists the minimum test report content. Users must record the reference to the standard, test date, sample identification, pretreatment and digestion, the result and any deviations or factors that could influence the result.

What terms does prEN 16175-1 define?

• CV-AAS - Cold-vapour atomic absorption spectrometry, the technique used to measure mercury vapour by its absorbance at 253.7 nm.
• Test solution - The aliquot of particle-free digest or extraction solution that is actually measured.
• Test blank solution - A blank prepared with the same reagents and procedure as the sample, but without the test solution, used for correction.
• Calibration blank solution - The zero-level calibration solution used to establish the instrument baseline and check the calibration range.
• Repeatability - The closeness of agreement between results under the same conditions, summarized in Annex A.
• Reproducibility - The closeness of agreement between results from different laboratories, also summarized in Annex A.

Who uses prEN 16175-1?

prEN 16175-1 is used by environmental, waste and soil laboratories that determine mercury in digests of soil, treated biowaste, sludge and waste. It is relevant to analysts, laboratory managers, quality managers and buyers of test services who need a mercury method for solid environmental matrices.

It is especially relevant where samples come from municipal sludge, compost and soil, because the introduction and Annex A show validation on those material types. The document also states that users should be trained in usual laboratory practice and able to manage safety and health conditions for strong-acid digests.

What changed in prEN 16175-1 from the previous edition?

prEN 16175-1 states that it will supersede EN 16175-1:2016. The foreword says the scope was updated to add EN ISO 54321 and EN 13656 digestion standards and to remove EN 16174. It also says the calibration range and stabilization reagents were opened, and Clause 6 on apparatus was revised.

Which standards are used with prEN 16175-1?

prEN 16175-1 is used together with the digestion and supporting standards it cites in the body and bibliography.

Standard	What it contributes
EN 16173	Nitric acid digestion of the sample before mercury determination
EN ISO 54321	Aqua regia digestion before mercury determination
EN 13656	Digestion with HCl, HNO3 and HBF4 or HF mixture before mercury determination
EN ISO 11465	Determination of dry matter fraction used in the final calculation
ISO 5725-2	Statistical basis used for the repeatability and reproducibility evaluation in Annex A

What does the prEN 16175-1 document contain?

The document contains the CV-AAS method itself, supporting notes on interferences, detailed reagent preparation, apparatus options and a step-by-step calibration and measurement sequence. It also contains the calculation formula for dry-matter-corrected mercury content and the required content of the test report.

Annex A gives interlaboratory comparison data for sludge, compost and soil materials, including repeatability and reproducibility statistics. That annex is useful for method validation, laboratory quality assessment and understanding how the method performed across participating European laboratories.

SLOVENSKI STANDARD
01-oktober-2026
Tla, obdelani biološki odpadki in blato - Določanje živega srebra - 1. del: Metoda
atomske absorpcijske spektrometrije s tehniko hladnih par (CV-AAS)
Soil, treated biowaste and sludge - Determination of mercury - Part 1: Cold-vapour
atomic absorption spectrometry (CV-AAS)
Schlamm, behandelter Bioabfall und Boden - Bestimmung von Quecksilber - Teil 1:
Kaltdampf-Atomabsorptionsspektrometrie (CV-AAS)
Boues, bio-déchets traités et sols - Détermination du mercure - Partie 1: Spectrométrie
d'absorption atomique de vapeur froide (SAA-VP)
Ta slovenski standard je istoveten z: prEN 16175-1
ICS:
13.030.20 Tekoči odpadki. Blato Liquid wastes. Sludge
13.080.10 Kemijske značilnosti tal Chemical characteristics of
soils
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2026
ICS 13.080.10 Will supersede EN 16175-1:2016
English Version
Soil, treated biowaste and sludge - Determination of
mercury - Part 1: Cold-vapour atomic absorption
spectrometry (CV-AAS)
Sols, biodéchets traités et boues - Détermination du Schlamm, behandelter Bioabfall und Boden -
mercure - Partie 1: Spectrométrie d'absorption Bestimmung von Quecksilber - Teil 1: Kaltdampf-
atomique à vapeur froide (SAA VF) Atomabsorptionsspektrometrie (CV-AAS)
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 444.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16175-1:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 5
5 Interferences . 5
6 Reagents . 6
7 Apparatus . 7
7.1 Usual laboratory apparatus . 7
7.2 Automated system with sample introduction, cold-vapour generator, flow injection
analysis and atom absorption spectrometer . 7
8 Procedure . 8
8.1 Test solution . 8
8.2 Test blank solution . 8
8.3 Preparation of the calibration solutions . 8
8.4 Instrumental set-up . 8
8.5 Calibration . 8
8.6 Measurement of test sample . 8
9 Calculation and expression of results . 9
9.1 Calculation . 9
9.2 Expression of results . 9
10 Performance data . 9
11 Test report . 10
Annex A (informative) Repeatability and reproducibility data . 11
Bibliography . 13

European foreword
This document (prEN 16175-1:2026) has been prepared by Technical Committee CEN/TC 444 “Test
methods for environmental characterization of solid matrices”, the secretariat of which is held by NEN.
This document is currently submitted to the-CEN Enquiry.
This document will supersede EN 16175-1:2016.
prEN 16175:2026 includes the following significant technical changes with respect to EN 16175-1:2016:
— EN ISO 54321 and EN 13656 digestion standards were added to the scope and EN 16174 is removed.
—- Calibration range and stabilization reagents were opened to customer belongings.
— Clause 6 Apparatus has been revised.
EN 16175, Sludge, treated biowaste and soil — Determination of mercury comprises the following parts:
— Part 1: Cold-vapour atomic absorption spectrometry (CV-AAS);
— Part 2: Cold-vapour atomic fluorescence spectrometry (CV-AFS).
Introduction
This document is applicable and validated for several types of matrices as indicated in Table 1 (see
Annex A for the results of validation).
Table 1 — Matrices for which this document is applicable and validated
Matrix Materials used for validation
Sludge Municipal sludge
Biowaste Compost
Soil Soil
WARNING — Persons using this document should be familiar with usual laboratory practice. This
document does not purport to address all of the safety problems, if any, associated with its use. It
is the responsibility of the user to establish appropriate safety and health practices and to ensure
compliance with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted according to this document be
carried out by suitably trained staff.
1 Scope
This document specifies a method for the determination of mercury in digests of soil, treated biowaste,
sludge and waste, obtained according to EN 16173 (nitric acid digestion), EN ISO 54321 (aqua regia
digestion) or EN 13656 (digestion with a hydrochloric (HCl), nitic (HNO ) and tetrafluoroboric (HBF ) or
3 4
hydrofluoric (HF) acid mixture) with using cold-vapour atomic absorption spectrometry (CV-AAS). The
lower working range limit is at least 0,03 mg/kg (dry matter basis) depending on digestion parameters.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
4 Principle
Mono- and divalent mercury is reduced to the elemental form by tin(II) chloride or sodium borohydride
in acid medium. Elemental mercury is stripped off from the solution in a closed system. The mercury
vapour, in the form of an atomic gas, passes through a cell positioned in the light path of an atomic
absorption spectrometer. Its absorbance at a wavelength of 253,7 nm is measured. The absorbance signal
is a function of mercury concentration, and the concentrations are calculated using a calibration curve.
The matrix of the solution analysed is dominated by the acids used in the digestion step. Tin(II) chloride
as a reduction substance is recommended in this document, because sodium borohydride reduces many
elements commonly found in soil, sludge and waste extract solutions, to the elemental state, which might
cause matrix problems under particular circumstances. However, it is still possible to use sodium
borohydride as reduction agent.
5 Interferences
Because the samples are digested with oxidizing, strong acids before determination of mercury starts,
there are no interferences with organic substances in the gas phase that can absorb in the UV range.
Neither are there any interferences with mercury compounds which cannot be fully reduced with tin(II)
chloride alone. The interferences due to the presence of other elements in the matrix depend on their
concentrations. Element concentrations exceeding those listed in Table 2 may cause negative bias.
Fewer interferences arise from heavy metals when tin(II) chloride is used rather than sodium
borohydride. When flow systems are used, interference effects due to heavy metals may be less than
indicated in Table 2.
Table 2 — Tolerable concentrations of some matrix elements
Element Acceptable
concentration in the test
solution
mg/l
Cu(II) 500
Ni(II) 500
Ag(I) 1
6 Reagents
For the determination of mercury at trace and ultra-trace level, the reagents shall be of adequate purity.
The concentration of mercury or interfering substances in the reagents and the water should be negligible
compared to the lowest concentration of mercury to be determined.
−1
6.1 Water, with an electrical conductivity less than 0,1 mS m (equivalent to resistivity greater than
0,01 MΩ m at 25°C). For all sample preparations and dilutions.
6.2 Carrier gas, argon or nitrogen, with a purity of ≥ 99,99 %.
6.3 Hydrochloric acid, HCl, ρ(HCl) = 1,15 g/ml - 1,18 g/ml, w(HCl) = 300 g/kg - 370 g/kg.
The same batch of hydrochloric acid shall be used throughout the procedure.
6.4 Nitric acid, HNO3, ρ(HNO3) = 1,4 g/ml, w(HNO3) = 650 g/kg.
The same batch of nitric acid shall be used throughout the procedure.
6.5 Nitric acid, diluted solution.
Dilute the digestion reagents (EN 16173) in the same way as the test solutions are diluted.
6.6 Nitric acid, c(HNO3) = 2 mol/l, rinsing solution for glassware.
Add 150 ml of nitric acid (6.4) to ab
...