🌱 Lead content in agricultural limes, calcium fertilizers and liming materials — flame atomic absorption spectrometry (FAAS), PN-C-87007-09

Physicochemistry PN-C-87007-09

Overview

WHAT THE STANDARD COVERS. The “Scope” field of the PKN card of PN-C-87007-09:1993 (Polish version), in full (spelling of the card): “Three methods are given for determining the lead content in calcium fertilizers; the atomic absorption spectrometry method using a graphite furnace, the AAS method in an acetylene-air flame and the voltammetric method. These methods are used for all calcium fertilizers. The conditions and the procedure for each method are specified”. The card does not say which clauses of the standard correspond to the three methods, how the sample solution is prepared or in what concentration range each of them is applied.

STATUS (PKN card as of 06.11.2026). The card of PN-C-87007-09:1993 (Polish version): label “Withdrawn”, title “Nawozy sztuczne wapniowe -- Oznaczanie zawartości ołowiu” (Calcium fertilizers — Determination of lead content), publication 22-02-1993, “Withdrawal date: 07-09-2015”, 4 pages, price group B, Chemistry Sector, KT 156 Fertilizers, ICS 65.080. The card has no “Replaces” or “Replaced by” fields — it does NOT indicate a successor. The same withdrawal date — 07-09-2015 — appears on the card of PN-C-87006-14:1993 (lead in calcium-magnesium fertilizers).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database refreshed from the production server on 02.11.2026, read on 06.11.2026; counted are records in which number 87007-09 appears in the reference document in any notation, also without the zero — “87007-9”). 8 records at 8 Polish laboratories, none at Czech laboratories. Notations: “PN-C-87007-09:1993” — AB 312, AB 333, AB 1186; “PN-C-87007-9:1993” — AB 930; “PN-93/C-87007/09 p.4.2” — AB 317; “PN-93/C-87007/09” — AB 779; “PN-C-87007-09:1993, p. 4.2” together with “PN-C-87006-14:1993, p. 4.2” — AB 339; together with PN-C-87006-14:1993 and PN-C-87070-05:1992 — AB 277. Clause 4.2 is indicated by 2 laboratories out of 8. In the current scope documents on the PCA website (read on 06.11.2026, issues from 24.06.2025 to 05.08.2026) the standard appears at the same 8 laboratories, once each, with the same notations and ranges as in the copy; none of these entries is suspended. The “Laboratories” tab (“PN-C-87007-09”) shows the same 8 laboratories — including those that write the number as “PN-93/C-87007/09” or “PN-C-87007-9” (query of the tab on labcoda.pl, 06.11.2026).

WHAT THE LABORATORIES TEST (complete entries). All 8 — “Lead content”, technique: flame atomic absorption spectrometry (FAAS). Objects and ranges: agricultural limes — AB 312 (5,0 – 200) mg/kg, AB 1186 (5,00 - 200) mg/kg; agricultural lime (calcium fertilizer) — AB 333 (5,0 - 5000) mg/kg; agricultural limes and liming materials — AB 317 (10,0 - 200) mg/kg, AB 779 (10,0 - 100) mg/kg; calcium fertilizers, liming materials — AB 930 (20,0 − 200) mg/kg; agricultural limes, liming materials — AB 339 (5,0 – 1000) mg/kg, in one entry with PN-C-87006-14:1993; mineral (inorganic) fertilizers — AB 277 (5,0 - 500) mg/kg, in one entry with PN-C-87006-14:1993 and PN-C-87070-05:1992. The ranges are given in mg/kg; the scope documents do not say whether this means a kilogram of fertilizer as delivered or of dry matter. At AB 339 and AB 277 one entry cites this standard together with the standard for calcium-magnesium fertilizers (and at AB 277 also with PN-C-87070-05:1992); the entries do not say which standard applies to which fertilizer.

PERMISSIBLE CONTENT IN LEGISLATION. Regulation of the Minister of Agriculture and Rural Development of 9 August 2024 on the implementation of certain provisions of the Act on fertilizers and fertilization (Journal of Laws 2024 item 1261, in force since 05.09.2024 according to the ELI service of the Sejm, read on 06.11.2026), § 13(3): the permissible content of contaminants in agricultural lime does not exceed 8 mg of cadmium (Cd) and 200 mg of lead (Pb) “per kilogram of calcium oxide (CaO)”; in agricultural lime containing magnesium — 15 mg of cadmium and 600 mg of lead per kilogram of the sum of calcium oxide and magnesium oxide (CaO + MgO). The same values and the same reference bases were contained in § 14(4) of the previous regulation of 18 June 2008 (Journal of Laws 2008 No. 119 item 765), deemed repealed as of 05.09.2024; the only regulation amending it (of 21 December 2009, Journal of Laws 2009 No. 224 item 1804) did not change § 14. The entire text of the 2024 regulation contains no reference to any standard or test method.

NEXT TO THIS STANDARD. Lead in limes containing magnesium is determined by the same 8 laboratories according to PN-C-87006-14:1993 (a separate Knowledge Base entry); that standard is also held by AB 798, which does not have lead in limes without magnesium in its scope. By ICP-OES, lead (together with cadmium, chromium and nickel) in agricultural limes and liming materials is determined according to PN-EN 16319+A1:2016-02 by AB 006 (1,00 - 500) mg/kg and AB 180 (2,00 - 300) mg/kg — without this standard. Cadmium in limes without magnesium is determined by laboratories of this group according to PN-EN 14888:2006 (AB 277, AB 312, AB 333, AB 339, AB 930, AB 1186) or an own procedure (AB 779 — PB 60).

STATUS OF THE STANDARDS NAMED ALONGSIDE (PKN cards, read on 06.11.2026). PN-C-87006-14:1993 — withdrawn 07-09-2015; PN-C-87070-05:1992 (lead in nitrogen and phosphorus fertilizers) — withdrawn 30-05-2014; PN-EN 16319+A1:2016-02 (English version, determination of cadmium, chromium, lead and nickel by ICP-AES after aqua regia dissolution; adopts EN 16319:2013+A1:2015) — no withdrawal label; PN-EN 14888:2006 (Polish version, “Fertilizers and liming materials — Determination of cadmium content”, adopts EN 14888:2005) — no withdrawal label; PN-C-87007-06:1993 (calcium oxide in calcium fertilizers) — withdrawn 07-09-2015; we did not check amendment Az1:1997 separately.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — the reference basis in the assessment: the value of 200 mg in the regulation refers to a kilogram of calcium oxide, whereas the laboratories report lead in mg/kg. A result in mg/kg of fertilizer compared directly with the number 200 looks compliant, although after conversion it may exceed it — our arithmetic example: 120 mg/kg of lead in a lime containing 50 % CaO is 240 mg per kilogram of CaO. The conversion requires the calcium oxide content of the same sample — in the scopes of 7 of these 8 laboratories determined according to PN-C-87007-06:1993 (a separate Knowledge Base entry; AB 339 determines calcium according to another standard); this is a separate determination, not part of this standard. The same number 200 appears as the upper limit of the accreditation range at AB 312, AB 317, AB 930 and AB 1186 — it is a limit of the measuring range in mg/kg, not the permissible value. Second — the type of lime: for lime containing magnesium the laboratories use a different standard (PN-C-87006-14), and the regulation a different criterion — 600 mg per kilogram of the sum of CaO + MgO; confusing the type changes both the method and the criterion. Third — the method: the card lists three methods — AAS with a graphite furnace, AAS in an acetylene–air flame and voltammetry — while the laboratories list one technique (FAAS); 2 out of 8 indicate “p. 4.2”, the others do not indicate a clause. Whether clause 4.2 is the flame method does not follow from the card (in the card description the flame method is the second of three) — when ordering, it is worth making sure which method was used for the determination.

WHAT WE DO NOT GIVE. We did not have the text of the standard — PKN makes it available for a fee (4 pages). We do not give the method of sample digestion, the wavelength, the calibration procedure, the formulas, the permissible difference between results or the content of clause 4.2, which two laboratories indicate. We did not check the requirements for liming materials in European Union legislation (CE-marked fertilizing products) — we describe only the national regulation.

Method principle

According to the PKN card, lead in a calcium fertilizer is determined by one of three methods: atomic absorption spectrometry with a graphite furnace, atomic absorption spectrometry in an acetylene–air flame or voltammetry. Accredited laboratories use the flame method (FAAS) and report the result in mg/kg. We DO NOT GIVE the determination conditions — we did not have the text of the standard.

Applications

• Lead in agricultural limes without magnesium, calcium fertilizers and liming materials — 8 Polish laboratories, all by FAAS
• Checking the permissible lead content in agricultural lime: 200 mg per kilogram of CaO (Journal of Laws 2024 item 1261, § 13(3))
• Limes containing magnesium — in the scopes of these laboratories according to PN-C-87006-14:1993, not according to this standard

Key parameters

Standard

Standard number

PN-C-87007-09:1993

Title (PL)

Nawozy sztuczne wapniowe — Oznaczanie zawartości ołowiu

Title (EN)

Calcium fertilizers — Determination of lead content

Step-by-step procedure

1. Status of the document

   PKN card: standard withdrawn 07-09-2015, without a successor being indicated (card as of 06.11.2026).

2. Type of lime

   Establishing whether the lime contains magnesium: for lime without magnesium the laboratories use this standard, for lime with magnesium — PN-C-87006-14:1993.

3. Determination of lead

   In accreditation scopes: flame atomic absorption spectrometry (FAAS), at 2 laboratories with the note “p. 4.2”; we DO NOT GIVE the sample digestion, calibration and measurement conditions.

4. Result

   Lead content in mg/kg; we DO NOT GIVE the formulas and the permissible difference between results.

5. Comparison with legislation

   The permissible value of 200 mg refers to a kilogram of calcium oxide (Journal of Laws 2024 item 1261, § 13(3)) — the comparison requires the CaO content of the same sample, determined separately.

Required equipment and apparatus

Health and safety (OHS)

• Lead and its compounds are toxic — standard solutions and waste are stored and disposed of as hazardous substances
• Flame in the AAS spectrometer: gas installation and fume hood above the burner
• SUBSTANTIVE NOTE: a result in mg/kg of fertilizer is not the same quantity as the permissible value in mg per kg of CaO

Frequently asked questions