Assessment of Human Health Risk in Groundwater at Rural and Agriculture Areas in Sabah, Malaysia

Abstract

Lack of treated water system in Sabah has increase human dependency to groundwater sources. The presence of contaminants such as nitrate in groundwater can pose severe health implications to human, such as methemoglobinemia and cancerous diseases. The objectives of this paper were to quantify the nitrate concentration in groundwater, to calculate potential human health risk exposure of nitrate in groundwater and to compare the potential human health risk exposure of nitrate between rural and agriculture areas. Six tube wells were selected at Inanam and Kota Belud district and involved one-hundred eighty respondents aged from 7 to 12 years old. The groundwater samples were analyzed using Cadmium Reduction method of HACH DR2800 Spectrophotometer and human health risk exposure were assessed using Chronic Daily Intake (CDI) and Hazard Index (HI) after set of information of respondents were obtained by questionnaires. Result obtained were showing mean ± S.D of nitrate levels in groundwater well and filtered water of agriculture (0.79 ± 0.33 mg/L; 0.33 ± 0.29 mg/L) and rural (0.50 ± 0.12mg/L; 0.53 ± 0.10 mg/L) areas were within the acceptable value limit set by National Drinking Water Quality Standard of Malaysia (10 mg/L). The statistical analysis of Kruskal-Wallis and one-way ANOVA test implied there were no significant differences of nitrate levels between two areas (p>0.05). Moreover, the mean ± S.D of CDI for agriculture and rural areas were 0.0064 ± 0.0056 mg/kg/day 0.0140 ± 0.0096 mg/kg/day respectively and HI were less than 1. The insignificant differences of potential human health risk were noted in terms of gender and age of respondents between two areas. This specified that the human health risk of respondents involved in this study was in acceptable range and not exposed to severe health risks.