vatnsgæða

Vatnsgæði, also written vatnsgæða, refers to the chemical, physical, and biological characteristics of water and its suitability for a given use, such as drinking, ecological health, recreation, or industry. The concept covers both natural background conditions and human-caused changes that may affect water resources.

Key indicators include physical properties (temperature, colour, turbidity, conductivity), chemical composition (pH, dissolved oxygen, nutrients such as nitrate and phosphate, major ions, metals, pesticides, and organic contaminants), and biological measures (microbial indicators such as E. coli, algae, and invertebrates). In drinking water, microbiological safety, disinfection residuals, and the removal of contaminants are essential considerations.

Monitoring involves sampling from rivers, lakes, groundwater, and coastal waters, followed by laboratory analysis and quality control. Quality standards are set by national authorities and international frameworks, with health-based limits for drinking water and ecosystem protection targets for other water bodies. When limits are exceeded, authorities may issue advisories, implement source-protection measures, or require treatment upgrades.

Common sources of degradation include agricultural runoff, wastewater discharges, industrial effluents, accidental spills, geothermal inputs, and natural geological factors. Climate change adds challenges through changed precipitation patterns, extremes of flood and drought, and warming waters, all of which can influence dilution, nutrient cycling, and habitat health.

Public reporting and data platforms provide transparency and support decision-making for managers, researchers, and the public. Ongoing research addresses emerging contaminants, microplastics, and integrated water-resource management.