⚛️ Cadmium in Water — GF-AAS
In short
Determination of trace concentrations of cadmium in surface water, groundwater and drinking water, waste water and sediments by atomic absorption spectrometry with electrothermal atomization in a graphite furnace (GF-AAS). The test is performed according to PN-EN ISO 15586:2005; Optimum working range (20 µl portion): 0.4–4 µg/l (Table 1). The procedure comprises 5 steps; it is used for: Drinking water — cadmium 5.0 µg/l (Journal of Laws 2026, item 748, Annex 1 Part B item 19), Waste water — reference methodology for cadmium (Journal of Laws 2019, item 1311, Annex 12 item 35), Monitoring of surface water and groundwater — indicator 4.1.6 “Cadmium and its compounds” (Journal of Laws 2021, item 1576, Annex 8).
At a glance
- Standard: PN-EN ISO 15586:2005
- Category: Physicochemistry
- Procedure steps: 5
- Optimum working range (20 µl portion): 0.4–4 µg/l (Table 1)
- Instrument detection limit: 0.1 µg/l — three times the standard deviation of repeated measurements of a blank (Table 1)
- Characteristic mass: about 0.7 pg — integrated absorbance 0.004 4 s (Table 1)
Overview
STATUS (as of 29.10.2026). PN-EN ISO 15586:2005 — Polish version, published 13.10.2005, implements EN ISO 15586:2003 and ISO 15586:2003 [IDT]; it replaced PN-EN ISO 15586:2004 (English version). The standard is current — no withdrawal note. ISO 15586:2003 (first edition, 08.10.2003) — no newer edition.
SCOPE (clause 1). Principles and procedures for the determination of trace levels of 17 elements (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, Zn) in surface water, groundwater, drinking water, waste water and sediments. The detection limit of the method depends on the sample matrix, the instrument, the type of atomizer and the use of chemical modifiers; for waters with a simple matrix (low content of dissolved solids and particles) it is close to the instrument detection limit. Table 1 gives for cadmium with a 20 µl portion: a characteristic mass of about 0.7 pg, an instrument detection limit of 0.1 µg/l (three times the standard deviation of repeated measurements of a blank) and an optimum working range of 0.4–4 µg/l (integrated absorbance 0.05–0.5 s).
PRINCIPLE (clause 3). Water samples are preserved with acid, filtered and preserved with acid, or digested (ISO 15587-1 — aqua regia, ISO 15587-2 — nitric acid); sediments are digested (Annex B). A small portion of the solution is injected into an electrically heated graphite furnace in which the temperature is raised stepwise: the sample is dried, pyrolized and atomized. The free atoms absorb radiation characteristic of the element determined; the concentration is determined by comparing the absorbance of the sample with the absorbance of calibration solutions. Interferences are overcome, if necessary, by a matrix modifier added to the samples before analysis or by calibration with the standard addition technique. The result is given in µg or mg per litre of water or per kilogram of dry mass of sediment.
LEGAL REQUIREMENTS. Drinking water: cadmium 5.0 µg/l (Journal of Laws 2026, item 748, Annex 1 Part B item 19); the method must be able to measure a concentration equal to the parametric value with a limit of quantification of not more than 30 % of that value and a measurement uncertainty of up to 25 % (Annex 4 Part B item 27). Waste water: PN-EN ISO 15586 is a reference methodology for cadmium (atomic absorption spectroscopy with flameless atomization) with the requirement: detection limit 0.1 of the permissible concentration at the sampling point, accuracy and precision ± 30 % at a concentration equal to the detection limit (Journal of Laws 2019, item 1311, Annex 12 item 35). Monitoring of surface water and groundwater: methodology for indicator 4.1.6 “Cadmium and its compounds”, alongside ICP-OES and ICP-MS (Journal of Laws 2021, item 1576, Annex 8).
WHAT WE DO NOT GIVE HERE. The publicly available text of the standard ends with clause 3. We do not give the reagents, apparatus, sample preparation (clause 7), chemical modification (clause 8), calibration (clause 10), precision data (clause 12) or the example instrument settings (informative Annex C). The wavelength of 228.8 nm comes from Table 4 of PN-ISO 8288 (the cadmium line in AAS) and from EPA Method 200.9 — not from the available text of ISO 15586.
Method principle
A portion of the sample is injected into the graphite furnace of an atomic absorption spectrometer; the furnace is electrically heated and dries, pyrolizes and atomizes the sample stepwise. A beam of radiation from a source characteristic of cadmium passes through the cloud of atoms and is selectively absorbed by them; the detector measures the decrease in intensity at the chosen wavelength, and the concentration is determined by comparison with calibration solutions. The integrated absorbance (peak area) is used for evaluation — the characteristic mass is expressed in it (clause 3, Table 1).
Cadmium line: 228.8 nm (Table 4 of PN-ISO 8288; EPA 200.9). EPA Method 200.9 (second source, a different document) uses a palladium + magnesium nitrate modifier and gives for cadmium example pyrolysis and atomization temperatures of 800 °C and 1600 °C, noting that the actual temperatures depend on the instrument and are determined individually.
Applications
- Drinking water — cadmium 5.0 µg/l (Journal of Laws 2026, item 748, Annex 1 Part B item 19)
- Waste water — reference methodology for cadmium (Journal of Laws 2019, item 1311, Annex 12 item 35)
- Monitoring of surface water and groundwater — indicator 4.1.6 “Cadmium and its compounds” (Journal of Laws 2021, item 1576, Annex 8)
- Sediments — after digestion according to Annex B of the standard (clauses 1, 3)
Key parameters
| Parameter | Value |
|---|---|
| Optimum working range (20 µl portion) | 0.4–4 µg/l (Table 1) |
| Instrument detection limit | 0.1 µg/l — three times the standard deviation of repeated measurements of a blank (Table 1) |
| Characteristic mass | about 0.7 pg — integrated absorbance 0.004 4 s (Table 1) |
| Wavelength | 228.8 nm (Table 4 of PN-ISO 8288; EPA 200.9 — outside the available text of ISO 15586) |
| Sample preparation | preservation with acid, filtration and preservation, or digestion according to ISO 15587-1 or ISO 15587-2 (clause 3) |
| Parametric value (drinking water) | 5.0 µg/l (Journal of Laws 2026, item 748, Annex 1 Part B item 19) |
Standard
- Standard number
- PN-EN ISO 15586:2005
- Title (PL)
- Jakość wody — Oznaczanie pierwiastków śladowych metodą atomowej spektrometrii absorpcyjnej z piecem grafitowym
- Title (EN)
- Water quality — Determination of trace elements using atomic absorption spectrometry with graphite furnace
Step-by-step procedure
-
Sampling and sample preparation
Take samples according to ISO 5667-1 to -6, -10, -11 and -15 (normative references of the standard); preserve with acid, filter and preserve, or digest according to ISO 15587-1 or ISO 15587-2 (clauses 2–3).
-
Sediments
Digest sediments according to the normative Annex B; report the result per kilogram of dry mass (clause 3).
-
Atomization
Inject a small portion of the sample solution into the graphite furnace; furnace programme: drying, pyrolysis, atomization (clause 3). Temperatures and times — according to clause 9 and the examples in Annex C (outside the available text).
-
Calibration
Determine the concentration by comparing the absorbance of the sample with the absorbance of calibration solutions; in case of interferences — a matrix modifier or the standard addition technique (clauses 3, 8, 10).
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Result
Report in µg/l or mg/l of water, for sediments in mg/kg of dry mass (clauses 3, 11).
Required equipment and apparatus
| Equipment | Example | Indicative price |
|---|---|---|
| Atomic absorption spectrometer with graphite furnace | electrothermal atomization in an electrically heated graphite furnace, radiation source characteristic of cadmium, detector (clause 3); detailed requirements for the apparatus (clause 6) — outside the available text | — |
Reagents, media and consumables
| Reagent | CAS | Details |
|---|---|---|
| Water | — | according to ISO 3696 (normative reference, clause 2); grade — outside the available text |
| Acids for preservation and digestion | — | nitric acid (ISO 15587-2) or aqua regia (ISO 15587-1) — according to clause 3 and the referenced standards |
| Cadmium stock solution, 1000 mg/l | — | preparation — informative Annex A of the standard (outside the available text) |
| Matrix modifier | — | choice — clause 8 of the standard (outside the available text); in EPA 200.9: 0.015 mg Pd + 0.01 mg Mg(NO₃)₂ per injection |
Health and safety (OHS)
- Acids, cadmium solutions and modifiers are handled according to the safety data sheets
- The graphite furnace spectrometer and the gas installation are operated according to the manufacturer’s instructions
Frequently asked questions
Which standard describes this test?
The test is performed according to PN-EN ISO 15586:2005 — “Water quality — Determination of trace elements using atomic absorption spectrometry with graphite furnace”.
How does this method work?
A portion of the sample is injected into the graphite furnace of an atomic absorption spectrometer; the furnace is electrically heated and dries, pyrolizes and atomizes the sample stepwise. A beam of radiation from a source characteristic of cadmium passes through the cloud of atoms and is selectively absorbed by them; the detector measures the decrease in intensity at the chosen wavelength, and the concentration is determined by comparison with calibration solutions.
What is the measuring range and accuracy?
Optimum working range (20 µl portion): 0.4–4 µg/l (Table 1); Instrument detection limit: 0.1 µg/l — three times the standard deviation of repeated measurements of a blank (Table 1); Characteristic mass: about 0.7 pg — integrated absorbance 0.004 4 s (Table 1); Wavelength: 228.8 nm (Table 4 of PN-ISO 8288; EPA 200.9 — outside the available text of ISO 15586).
How long does the test take?
The procedure comprises 5 steps. The standard does not give a duration for every stage — the laboratory's own procedure decides.
What equipment is required?
Atomic absorption spectrometer with graphite furnace.
Where is this test used?
Drinking water — cadmium 5.0 µg/l (Journal of Laws 2026, item 748, Annex 1 Part B item 19); Waste water — reference methodology for cadmium (Journal of Laws 2019, item 1311, Annex 12 item 35); Monitoring of surface water and groundwater — indicator 4.1.6 “Cadmium and its compounds” (Journal of Laws 2021, item 1576, Annex 8); Sediments — after digestion according to Annex B of the standard (clauses 1, 3).
What safety precautions apply?
Acids, cadmium solutions and modifiers are handled according to the safety data sheets; The graphite furnace spectrometer and the gas installation are operated according to the manufacturer’s instructions.
Which laboratory can perform this test?
The test is performed by laboratories accredited to ISO/IEC 17025. On LabCoda you can find them by the standard number PN-EN ISO 15586.