Factors affecting the nitrate concentration and its health risk assessment in drinking groundwater by application of Monte Carlo simulation and geographic information system

摘要

This study aimed to investigate the effect of anthropogenic factors, including land use, environmental factors, and topography at a radius of 400 m around the wells on nitrate concentration so as to assess the health risk from nitrate concentration and accordingly analyze its sensitivity using field and software surveys. In this study, 70 samples of drinking water were taken from 35 wells in two seasons: low rainfall and high rainfall in 2017 and the concentration of nitrate was determined using spectrophotometry. The area of four types of land use in a radius of wells was determined using Google Earth and GIS software. Pearson correlation and t-test were employed to determine the effect of the above factors on nitrate concentration by SPSS. Health risk assessment was performed for three age groups and analyzed by a sensitivity analysis using Monte Carlo. The results showed that eight samples (11.4%) exceeded the recommended. limit of 50 mg/L. The concentration of nitrate in wells without sanitary protection area was 51.1 +/- 11.01. The wells at the bottom of the groundwater flow have an average nitrate concentration of 41.39 +/- 11.85. The highest CDI (0.98 mg/kg) and HQ (0.75) values were belonged to age group of 0-6 years; approximately 90% of this age group was at high risk during this high rainfall season. Nitrate concentration was recognized as the most effective factor in the non-carcinogenicity risk of nitrates.