🌿 Determination of elements in sewage sludge, treated biowaste and soil by ICP-OES — solutions after digestion with aqua regia according to EN 16174 or nitric acid according to EN 16173 (tin only after aqua regia); sequential or simultaneous spectrometer, axial or radial viewing; background correction, inter-element correction or multicomponent spectral fitting, internal standard (Sc, Y, Lu, 1–10 mg/l), acid matching, calibration and interference check solutions, rinsing between samples; result on dry matter according to EN 15934, PN-EN 16170

Environment PN-EN 16170

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of SIST EN 16170:2017, i.e. EN 16170:2016 (English text): contents, European foreword, introduction, Clauses 1–6 and Clause 7 up to 7.3.2 (inter-element correction) — the sample ends on page 9. We do not read calibration (7.4), sample measurement (7.5), calculation (8), expression of results (9), performance characteristics (10), the test report (11) or Annexes A (repeatability and reproducibility), B (wavelengths, spectral interferences, detection limits) and C (inter-element correction); we know the titles from the contents.

ACCORDING TO THE TEXT OF EN 16170:2016. The standard was prepared by CEN/TC 444 “Test methods for environmental characterization of solid matrices” (secretariat NEN); approved by CEN on 19.03.2016, corrected and reissued on 09.11.2016; national standards had to adopt it, and withdraw conflicting ones, by April 2017 at the latest; it supersedes CEN/TS 16170:2012, whose preparation followed European Commission mandate M/330 (standards for sludge, treated biowaste and soil); technical change: repeatability and reproducibility data from a European interlaboratory comparison organized by BAM in 2013 were added (Annex A). Introduction: the standard is applicable and validated for sludge (municipal sludge), biowaste (compost) and soil (Table 1); tests must be carried out by suitably trained staff. Scope (1): determination in aqua regia or nitric acid digests of the following elements: Al, Sb, As, Ba, Be, Bi, B, Cd, Ca, Ce, Cr, Co, Cu, Ga, In, Fe, La, Pb, Li, Mg, Mn, Hg, Mo, Nd, Ni, P, K, Pr, Sm, Sc, Se, Si, Ag, Na, Sr, S, Te, Tl, Th, Sn, Ti, W, U, V, Zn, Zr; validated for the elements in Table A.1, applicable for the others after verification by the user. References (2): EN 15934 (dry matter), EN 16173 (nitric acid digestion), EN 16174 (aqua regia digestion), EN ISO 3696. Principle (3): solutions are analysed by ICP-OES with a sequential or simultaneous optical system and axial or radial plasma viewing; the aerosol from the nebulizer is transported to the torch, the radio-frequency inductively coupled plasma produces characteristic spectra, which are dispersed by a grating and measured by detectors; note: tin is determined only after aqua regia extraction (EN 16174). Interferences (4): background correction required for trace determination (except with line broadening, where it would degrade the result); spectral interferences (background, stray light, overlap of lines and molecular bands) — subtraction of background measured next to the peak, spectral scans of samples and single-element solutions, alternative lines, multicomponent spectral fitting or inter-element correction equations (interfering elements determined simultaneously); uncorrected interferences give false positive results, listed in Table B.1; physical interferences (viscosity, surface tension, high dissolved solids or acid) — dilution, acid and matrix matching, high-solids nebulizer, correction with an internal standard; chemical interferences usually insignificant in ICP, if necessary choice of conditions, buffering, matrix matching, standard addition; memory effects — rinsing between samples, rinse times established during method development. Reagents (5): purity adequate for trace and ultra-trace levels; grade 2 water; HNO3 1,4 g/ml (15 mol/l), HCl 1,18 g/ml (12 mol/l); single-element stock solutions 1000 mg/l; multi-element A (e.g. Ag, Al, As, Cd, Cr, Cu, Hg, Pb, Zn — stabilized with HNO3), B (Mo, Sb, Si, Sn, W, Zr — HCl), C (Ca, Mg, Na, K, P, S — HNO3); stable for months in the dark, except those prone to hydrolysis (Bi, Mo, Sn, Sb, Te, W, Zr); calibration solutions with acidity close to the samples, checked against an independent standard if traceability is not established; during digestion Al, Na, K, Ca, Mg, Ti and Fe are co-extracted at several hundred mg/l — the efficiency of interference compensation is checked with control and interference check samples, otherwise the matrix of calibration solutions is matched for each batch or standard addition is used; internal standard — elements not determined and absent from samples, e.g. Sc, Y, Lu, 1–10 mg/l; calibration blank, test blank going through the whole procedure, calibration check solution from an independent standard, interference check solution (at most one interfering element per analyte; spike with analyte 0,5–1 mg/l so that overcorrection is not hidden as zero). Apparatus (6): argon ICP-OES spectrometer (axial viewing gives a stronger signal but usually more interference than radial), computer-controlled, with background correction; RF generator, mass flow controller for argon, peristaltic pump, optionally autosampler; argon e.g. ≥ 99,95 %. Procedure (7.1–7.3): test sample solution — clear digest according to EN 16173 or EN 16174; test solution — directly or after dilution, with the acidity of the calibration solutions matched to it; instrument parameters according to the manufacturer, method adapted to the sample type; lines and corrections according to Table B.1; rinse time to blank level; notes: guidance on method development in EN ISO 11885; not all elements can be determined optimally in one run; inter-element correction is needed when the interfering elements of Table B.1 give values greater than three times the instrumental detection limit or half the lowest reported concentration (factors according to Annex C).

STATUS (as of 03.10.2026). In the PKN search (term “16170”, 03.10.2026) PN-EN 16170:2017-02 (English version, “Introduces: EN 16170:2016 [IDT]”) carries the note “Withdrawn and replaced by PN-EN ISO 22036:2024-07 – English version”; the second result, PN-EN ISO 16170:2016-09, is an unrelated standard on testing filter systems. Card: publication date 07.02.2017, withdrawal date 05.07.2024, 27 pages, KT 216 Waste, ICS 13.030.01 and 13.080.10, “Withdrawn and replaced by PN-EN ISO 22036:2024-07 – English version”. In the iTeh catalogue (read 03.10.2026) EN 16170:2016 has the status “Withdrawn”, stage 99.60, replaced by EN ISO 22036:2024 (“Environmental solid matrices — Determination of elements using inductively coupled plasma optical emission spectrometry (ICP-OES)”); the withdrawal date field on the CEN card is 30.09.2026; SIST EN 16170:2017 — “Withdrawn” since 10.05.2024.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read 03.10.2026). The number 16170 (without ISO) appears in 4 records at 2 laboratories: AB 667 (3), AB 1249 (1). In the current PCA documents (read 03.10.2026; AB 667 issue No. 28 of 14.11.2025, AB 1249 issue No. 16 of 19.01.2026) the number appears in 4 lines at the same 2 laboratories (3 and 1); in each document the number of page markers equals the number of PDF pages, without repetitions; a search of all PCA documents downloaded from the BIP on 03.10.2026 found no laboratories outside the database copy. Form “PN-EN 16170:2017-02” at both, without a digestion standard in the same cell. None of these items is suspended. The “Laboratories” tab (term “PN-EN 16170”) shows both laboratories — checked by a tab query on the labcoda.pl production server on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). AB 667 (ICP-OES): soil — chromium (1,0–5000), zinc (10–10 000), lead (0,1–5000), cadmium (0,05–50), nickel (0,2–5000), copper (5,0–5000), mercury (0,5–50) mg/kg; sewage sludge and waste with code 19 08 05 — the same elements plus phosphorus (1,0–5000) mg/kg, magnesium (100–15 000) mg/kg or (0,010–1,50) % and calcium (100–150 000) mg/kg or (0,010–15,0) %. AB 1249 (ICP-OES): soil, fertilizers — compost, sewage sludge — arsenic (3,0–5000), barium, chromium, tin, zinc, cobalt, copper, manganese, molybdenum, nickel, lead, magnesium (each 1,0–5000), cadmium (0,25–5000), mercury (0,50–2500), phosphorus (5,0–5000), calcium and potassium (125–25 000) mg/kg.

ALONGSIDE THIS STANDARD. The successor, PN-EN ISO 22036:2024-07, is a separate entry in the knowledge base; in the current PCA documents (read 03.10.2026) the form “PN-EN ISO 22036:2024-07” appears at 10 laboratories: AB 127, AB 165, AB 176, AB 213, AB 415, AB 817, AB 1173, AB 1539, AB 1717, AB 1752 — none of them is one of the two laboratories with PN-EN 16170. The knowledge base also contains the digestion standards PN-EN 16173 and PN-EN 16174 and PN-EN ISO 11885 (ICP-OES in water).

WHERE AN APPARENTLY CORRECT RESULT IS EASY TO GET. With the status: the standard has been withdrawn since 05.07.2024 and replaced by PN-EN ISO 22036:2024-07 — the PCA items still cite it. With digestion: the result refers to the fraction soluble in aqua regia or in nitric acid (1, 3) — the type of digestion must be stated with the result, and the PCA items do not name the digestion standard; tin is determined only after aqua regia (3, note) — AB 1249 has tin in its scope. With interferences: uncorrected spectral interferences give false positive results (4); co-extracted Al, Na, K, Ca, Mg, Ti and Fe at several hundred mg/l require checking of the compensation with control samples, or matrix matching or standard addition (5.6); overcorrection may be hidden when the instrument records negative values as zero (5.11). With axial viewing: stronger signal but usually more interference (6.1). With elements outside the validation: for elements not in Table A.1 the user verifies applicability (1). With the matrix: validation covered municipal sludge, compost and soil (Table 1) — AB 667 also applies the standard to waste 19 08 05.

WHAT WE DO NOT GIVE. We do not quote calibration, measurement, formulae, the wavelengths and detection limits of Table B.1, repeatability and reproducibility data or inter-element correction factors — they lie outside the sample. We do not summarize PN-EN ISO 22036:2024, EN 16173, EN 16174 or EN 15934 in this entry. We do not give limit values for metals in sludge and soil.

Method principle

A solution obtained from sludge, treated biowaste or soil by digestion with aqua regia (EN 16174) or nitric acid (EN 16173) is nebulized into an argon plasma excited by radio frequency; excited atoms emit radiation at characteristic lines, which the spectrometer grating disperses, and detectors measure the intensity. The element concentration is read from calibration with acid-matched solutions, with background correction, inter-element correction and an internal standard, and converted to the content in dry matter.

Applications

• Elements in aqua regia or nitric acid digests of sewage sludge, treated biowaste and soil (1)
• Validation: municipal sludge, compost, soil (Table 1)
• Soil, compost, sewage sludge and waste 19 08 05 — 4 items in the accreditation scopes of 2 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN 16170:2017-02

Title (PL)

Osady ściekowe, uzdatnione bioodpady oraz gleba — Oznaczanie zawartości pierwiastków z zastosowaniem optycznej spektrometrii emisyjnej z plazmą sprzężoną indukcyjnie (ICP-OES)

Title (EN)

Sludge, treated biowaste and soil — Determination of elements using inductively coupled plasma optical emission spectrometry (ICP-OES)

Step-by-step procedure

1. Digestion

   Aqua regia according to EN 16174 or HNO3 according to EN 16173; clear solution (7.1). PN-EN 16170:2017-02 withdrawn on 05.07.2024 (PKN).

2. Test solution

   Directly or after dilution; calibration acidity matched (7.2).

3. Instrument set-up

   Parameters, lines and corrections according to Table B.1, rinse times (7.3.1).

4. Interference correction

   Checking interfering elements, inter-element correction factors (7.3.2, Annex C).

5. Calibration, measurement and result

   Calibration and interference checks, conversion to dry matter according to EN 15934 (7.4–9 outside the sample).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The standard does not address all safety problems; tests are carried out by trained staff (introduction)
• Concentrated nitric and hydrochloric acids are corrosive (5.2, 5.3)

Frequently asked questions