Porevattnet

Porevattnet refers to the water that fills the void spaces between soil grains, sediment particles, or rock pores. In fully saturated conditions the pore water is the principal phase carrying dissolved substances, and its composition can differ markedly from the water outside the pore spaces. In unsaturated soils, pore water coexists with air and is held by capillary forces, slowly changing as evaporation and infiltration occur.

In soils and sediments, porevattnet is central to nutrient availability, microbial metabolism, and geochemical weathering. Its chemistry is controlled by mineral dissolution and precipitation, adsorption and desorption on particle surfaces, and redox reactions driven by microbial activity. The pore water composition can indicate processes such as nitrate reduction, sulfate reduction, or metal dissolution, and it governs the mobility and bioavailability of nutrients and contaminants.

Sampling and analysis: Pore water is collected using methods such as rhizon samplers, diffusion samplers (peepers), suction lysimeters, or direct squeezing of sediments. Careful handling is required to preserve redox-sensitive species and to avoid altering pH, dissolved oxygen, or concentrations during transit. Common measurements include pH, redox potential, dissolved oxygen, electrical conductivity, major ions, nutrients (nitrate, ammonium, phosphate), dissolved organic carbon, and trace metals or metalloids.

Applications: Porevattnet data are used in groundwater and environmental risk assessments, studies of nutrient cycling in soils and wetlands, estuarine and coastal sediment chemistry, and evaluations of contaminant mobility from soils to water bodies. The term porevattnet is widely used in Nordic-language literature on soil science and geochemistry.