Road salt retention and transport through vadose zone soils to shallow groundwater

Increasing background salinity in watersheds has largely been attributed to road salt retention groundwaters due their long residence times. However, laboratory studies demonstrate that soils temporarily store salts, either porewater or adsorbed onto particles. Field of are nevertheless rare, and mechanisms transport across multiple hydrological reservoirs (e.g., from soil groundwater) unknown. Thus, we collected roadside karst spring water weekly for ~1.5 yr determine through the vadose zone into phreatic zone. We observed dual sodium (Na+) chloride (Cl?) slow movement, causing ion movement as 1.3 cm/day, cation exchange processes, leading initial Na+ followed by later release months after application. Cation processes also caused base loss sites mobile porewater. Rapid Cl? delivery groundwater occurred conduits during winter. elevated levels ions non-salting indicated accumulation catchment slower flow rock matrix delayed sites.