Overview
ISO 10260:1992 sets out a standardized method for determining the concentration of chlorophyll-a in water using spectrometric analysis. Chlorophyll-a is a key photosynthetic pigment in green plants and algae, and its concentration serves as a reliable indicator of biological activity and trophic state in aquatic environments. This international standard, developed by ISO, applies primarily to phytoplankton in natural surface waters and also supports the testing of algal growth in bioassays. With suitable sampling, the procedure can be adapted for analyzing phytobenthic (attached algal) communities.
The method focuses on collecting algae via filtration, extracting pigments using hot ethanol, and measuring chlorophyll-a concentration spectrometrically by assessing the absorbance at 665 nm before and after acidifying the extract.
Key Topics
- Water Quality Assessment: Chlorophyll-a measurement is fundamental for evaluating water quality, providing insight into algal abundance and the productivity of aquatic systems.
- Spectrometric Analysis: The technique uses visible-range spectrometry, quantifying the absorbance at specific wavelengths (primarily 665 nm) to determine pigment concentrations accurately.
- Sampling and Sample Preservation: The standard emphasizes rigorous sampling protocols and stresses the importance of minimizing pigment degradation by immediate sample processing or cold storage in the dark.
- Extraction Procedure: Ethanol is recommended as the extractant, heated to optimize pigment release and chlorophyllase inactivation. Methanol may be used under certain conditions, but ethanol is preferred for consistency and safety.
- Interferences: The procedure corrects for turbidity using dual-wavelength measurement (665 nm and 750 nm) and accounts for potential interference by other pigments or phaeopigments.
Applications
ISO 10260:1992 is widely applied in:
- Environmental Monitoring: Regulatory agencies and research institutions utilize this method for routine monitoring of lakes, rivers, reservoirs, and coastal environments to gauge nutrient loading and eutrophication.
- Algal Bloom Studies: Quantifying chlorophyll-a is essential for tracking algal blooms, assessing their impact, and supporting water management decisions.
- Bioassays and Laboratory Studies: The standard method is suitable for laboratory-based algal growth assessments, including ecotoxicological evaluations.
- Phytobenthic Analysis: With adapted sampling, researchers can determine chlorophyll-a in attached algal communities, aiding in comprehensive ecological assessments.
By providing a harmonized approach, ISO 10260:1992 ensures consistency, comparability, and reliability in chlorophyll-a data across different laboratories and studies.
Related Standards
The procedures in ISO 10260:1992 directly reference and complement several other international water quality standards, notably:
- ISO 5667-1:1980, Water quality - Sampling - Part 1: Guidance on the design of sampling programmes
- ISO 5667-2:1991, Water quality - Sampling - Part 2: Guidance on sampling techniques
Other related standards and publications address spectrometric techniques, sample handling, and algal pigment analysis. Together, these standards enable comprehensive assessments of aquatic ecosystems, fostering best practices in environmental monitoring and chemical analysis.
Keywords: ISO 10260, water quality, chlorophyll-a, spectrometric determination, phytoplankton, aquatic ecosystems, algal pigments, environmental monitoring, biochemical parameters, standard methods, water analysis