Groundwater quality determination using stable isotopes

Alluvial plains are an important agricultural area because of favourable soil properties, topography, and proximity to surface and groundwater resources. The predominant land use in the alluvial plains is agriculture, but there are also many urban and industrial areas. Groundwater bodies beneath the alluvial plains are threatened by nitrate pollution from agricultural activities and urban sources such as faulty sewage systems. For the Krško-Brežiško polje case study, an assessment of nitrate sources in groundwater was conducted using stable isotopes (δ¹⁵N) to produce maps of groundwater vulnerability. In addition, stable isotope composition of groundwater (δ¹⁸O and δ²H) was used to obtain information on the characteristics of the recharge area. Nuclear techniques (i.e., stable isotopes) are excellent for determining pathways and travel times of contaminants through the vadose zone in soil-groundwater systems, especially in areas with shallow aquifers. Results show contamination from manure application and the potential to reduce pressures on groundwater for specific sampling points.

This research was financed by the ARRS L4-8221 URAVIVO and IAEA TCP SLO5004 Improving Water Quality in Vulnerable and Shallow Aquifers under Two Intensive Fruit and Vegetable Production Zones.