Spectrophotometric Determination of Iron Concentration in Groundwater Samples from Al-Najila Agricultural Area

Abstract

This study aims to estimate the concentration of iron and assess the extent of groundwater contamination by collecting eighteen random groundwater samples from the Al-Najila agricultural area. Additionally, the study seeks to evaluate the compliance of these concentrations with drinking water quality standards and to identify the environmental and health impacts associated with iron contamination in groundwater. For the purpose, iron concentrations were determined using the FerroVerspectrophotometric method, which involves converting all forms of iron in the sample into a soluble form through a reaction with 1,10-orthophenanthroline present in the reagent, forming an orange-coloured complex. The absorbance was measured using a spectrophotometer (DR 6000) at a wavelength of 510 nm. The results showed that iron concentrations in the samples ranged from 0.03 mg/L to 0.37 mg/L. To verify the accuracy of the analysis, the standard addition method was applied, yielding a linear equation of y = 2.083x + 0.0348 with a correlation coefficient of r² = 0.9992, indicating high precision and consistency of the results. Besides, the obtained values were compared with the Libyan national standards and the World Health Organization (WHO) guidelines for drinking water, both of which set the maximum allowable concentration of iron at 0.3 mg/L. It was confirmed that all samples were within the acceptable range, except for one that slightly exceeded the recommended limit. Conclusively, iron concentrations in the groundwater of the study area generally comply with the established standards. However, continuous monitoring is recommended to track changes in iron levels, identify potential sources of contamination, and implement appropriate preventive measures