Spatial variation of boron in groundwater in South Iraq

Abstract

The research investigated boron variability in space and time, using 450 groundwater samples from 75 representative wells in the Safwan–Zubair area of Basra district, South Iraq, collected monthly from January to June 2000, with also 75 soil samples from selected farms in the same area. Minimum and maximum values of boron concentrations range from 1.49 to 9.49 ppm respectively. Boron concentration in groundwater spatially occurs in 90% in frequency between 2 and 4 ppm, while 5% below 2 ppm and 5% is more than 4.0 ppm to more than 9.0 ppm, where the soluble boron concentrations of soil samples range from 0.60 to 7.02 ppm. Soil boron concentration spatially occurs 95% below 6.0 ppm and 5% more than 6.0 ppm. The results show that the variability of boron concentration in groundwater and in soil mostly depends upon irrigation water, cyclic differences of the sediment facies horizontally and vertically, and also the period of precipitation (rainfall); i.e. wetting and drying processes. The results indicate that there will always be available boron in the soil at the end of the irrigation period (May–June) ready to be leached again by the first percolated rainfall (effective rainfall) to join the groundwater at higher concentration. The results show that the variability of boron concentration in groundwater and in soil mostly depends upon irrigation water, cyclic differences of the sediment facies horizontally and vertically, and also the period of precipitation (rainfall); i.e. wetting and drying processes. The results indicate that there will always be available boron in the soil at the end of the irrigation period (May–June) ready to be leached again by the first percolated rainfall (effective rainfall) to join the groundwater at higher concentration.