ISO 14442:2006

Overview

ISO 14442:2006 - "Water quality - Guidelines for algal growth inhibition tests with poorly soluble materials, volatile compounds, metals and waste water" provides practical procedures for conducting algal growth inhibition tests when standard methods (ISO 8692, ISO 10253) are not applicable. The guideline covers preparation and addition of difficult-to-test substances and includes advice on analytical confirmation, stability, and interpretation of results. It addresses a wide range of test materials including poorly soluble organics and inorganics, volatile compounds, heavy-metal-containing samples, coloured/turbid waters, and waste waters or environmental samples with sediments.

Key topics and technical requirements

• Scope of substances: poorly soluble pure organics and mixtures, poorly soluble inorganic materials, volatile substances, waste waters, coloured/turbid samples, and heavy-metal compounds.
• Methods of addition: direct addition, dispersion, and preparation of water-soluble or water‑accommodated fractions.
• Preparation techniques: guidance on making saturated and supersaturated solutions (e.g., stirring-practical equilibration ~20 h, up to 3 days where required), solvent carriers for low-concentration organics, mechanical dispersion (high-speed blending, ultrasonic treatment - guidance in standard), and use of emulsifying agents.
• Analytical confirmation: recommended (and required for volatile compounds) measurement of test substance concentrations and stability in the test medium to support EC calculations and interpretation.
• Test-system considerations: handling losses (biodegradation, photodegradation, adsorption) inherent in batch algal tests, pH buffering, and ways to minimise artefacts (sterilisation, glassware treatment, pre‑conditioning).
• Interference and interpretation: procedures for assessing interference from coloured/turbid samples, nutrient alterations from complex matrices, and guidance for interpreting results where matrix effects occur.

Applications and users

ISO 14442:2006 is intended for:

• Environmental and ecotoxicology laboratories conducting algal growth inhibition testing
• Regulatory agencies and assessors performing environmental risk assessments
• Chemical manufacturers and product stewardship teams testing poorly soluble or volatile substances
• Wastewater and environmental monitoring organisations assessing effluent toxicity or sediment‑associated effects

Practical uses include derivation of toxicity endpoints for environmental hazard assessment, method adaptation for complex matrices, and harmonised testing protocols to support regulatory submissions.

Related standards

• ISO 8692 - Freshwater algal growth inhibition test
• ISO 10253 - Marine algal growth inhibition test
• ISO 5667-16 - Guidance on biotesting of sampled waters

Keywords: ISO 14442:2006, algal growth inhibition tests, poorly soluble materials, volatile compounds, heavy metals, waste water, water quality, ecotoxicology.