## 4 Results and Discussion
### Water Quality for Various Utilization
#### 4.2.2 Potential Health Threats of Toxic Elements to Humans  
In addition to the EWQI, the non-carcinogenic health risks potentially posed by toxic substances also serve as another significant indicator in assessing groundwater quality [53]. In this study, the exceedingly toxic substances, including NO3\({}^{-}\), NO2\({}^{-}\), and F\({}^{-}\), may pose  
Figure 4: (**a**) Scatterplot of EWQI versus TDS, and (**b**) the spatial interpolation graph of EWQI of groundwater within the basin.  
a significantly apparent non-carcinogenic risk to the population in the study area. For example, the excessive nitrogen in drinking water would result in dysfunction of blood transporting oxygen and cancers of the colon and stomach [14; 54; 55]. When examining the susceptibility of different demographic groups to these substances, it's prudent to categorize the population by age and gender, as this study does, into infants, children, adult males, and adult females [56]. This approach allows for a more nuanced understanding of how various groups may be affected by the presence of these substances in the groundwater. By taking into account the specific vulnerabilities of these groups, more targeted measures can be implemented to mitigate potential health risks and ensure the safety of the groundwater supply.  
The results indicate that the average non-carcinogenic health risks of groundwater for infants, children, adult females, and adult males are 2.803, 1.738, 1.240, and 1.555, respectively (Table 3). Infants, due to their inherent vulnerability, exhibit the highest non-carcinogenic health risks, followed by children, adult males, and adult females. For infants and children, a considerable proportion of the population, specifically 62.5% and 66.7%, respectively, are exposed to moderate non-carcinogenic health risks (Figure 5). Furthermore, a significant subset of infants, amounting to 29.2%, are exposed to a high degree of non-carcinogenic risk. Adult males and females are not significantly exposed to high risk; rather, the proportion of those exposed to moderate risk is 58.3% and 66.7%, respectively. In conclusion, the non-cancer risks to infants in the study area are extremely high. Failure to take timely and appropriate action may result in irreversible damage to the health and development of the infant population.  
The spatial distribution of non-carcinogenic health risks is depicted in Figure 6. It is apparent that the spatial distribution of non-carcinogenic risks closely mirrors the pattern observed in the EWQI distribution. Groundwater in the downstream regions demonstrates elevated non-carcinogenic risks across all age groups. Particularly for infants, groundwater samples with hazard index (HI) values exceeding 3 are predominantly located in the downstream regions of the basin. This distribution pattern is tentatively attributed to the higher population density and concentrated human activities in the downstream areas. The elevated non-carcinogenic risks in groundwater are likely due to the discharge of domestic wastewater and livestock manure, as well as the application of fertilizers. Accordingly, this study suggests implementing tailored water supply strategies for different demographic groups. Furthermore, it is imperative for areas with substantial non-carcinogenic risks to augment the purification of nitrates and fluorides in groundwater, thereby fundamentally mitigating these health hazards.