ISO 17586:2016

Overview

ISO 17586:2016 - "Soil quality - Extraction of trace elements using dilute nitric acid" specifies a standardized laboratory procedure for extracting the potentially environmentally available trace elements from soils using a dilute nitric acid solution (target pH ≈ 0.5). The method is applicable to all soils and soil‑like materials and yields extracts suitable for sensitive analytical techniques (ICP‑MS, ICP‑OES, AAS) to quantify trace metals for environmental assessment and monitoring.

Key topics and technical requirements

• Extraction chemistry: Use a dilute nitric acid solution of (0.43 ± 0.02) mol·L⁻¹ to achieve an extract pH typically between 0.5 and 1.0 (for highly calcareous soils final pH should be < 1.0).
• Soil preparation: Test portion particle size ≤ 2 mm; oversized non‑natural materials removed; drying temperature must not exceed 25 °C; do not finely grind samples.
• Soil:solution ratio & conditions: 10 g soil with 100 mL acid (soil:solution 1:10 m/V), extracted for 120 ± 5 minutes at 20 ± 2 °C on an end‑over‑end shaker (~25 rpm).
• Carbonate correction: Add 0.50 mL of 5 mol·L⁻¹ HNO3 per % CaCO3 above 5 % to account for acid neutralization in calcareous soils.
• Phase separation & filtration: Centrifuge at ≥ 1 000 g for 10 min; filter supernatant using an in‑line 0.45 µm membrane filter (use 0.2 µm if turbid).
• Analytical measurement: Extracts are compatible with ICP‑MS, ICP‑OES, flame or electrothermal AAS (apply matrix matching and blank correction).
• Quality control: Use ISO 3696 water, analytical‑grade reagents, blanks, and cleaned glassware (e.g., 5 % HNO3 rinse).
• Results & reporting: Report trace element mass fractions in µg/kg. Test report must reference ISO 17586 and include sample ID, pretreatment, dry matter content (ISO 11465), analytical results and any deviations.

Practical applications and users

ISO 17586 is used by:

• Environmental and commercial soil testing laboratories
• Regulatory agencies conducting soil contamination and risk assessments
• Remediation practitioners and site assessors for baseline and post‑remediation monitoring
• Soil scientists and agronomists studying trace metal bioavailability

Typical applications: assessing potential environmental availability of metals (as defined in ISO 17402), contaminated land investigations, monitoring changes over time, and supporting decisions on land use and remediation.

Related standards

• ISO 17402 - Environmental availability concept referenced by ISO 17586
• ISO 11464, ISO 11465 - Sample pretreatment and dry matter/water content
• ISO 3696 - Water for analytical laboratory use
• ISO 17294‑2, ISO 22036, ISO 11047, ISO 20280 - Analytical methods (ICP‑MS, ICP‑OES, AAS)

Keywords: ISO 17586, soil quality, dilute nitric acid extraction, trace elements, soil testing, environmental availability, ICP‑MS, ICP‑OES, AAS, calcareous soils.