**6.5 Urine sample analysis survey**

The urine sample analysis survey is carried out alongside, the dental survey. F is excreted primarily through urine [34], which is an early indicator of fluoride poisoning. The F content in urine depends on the concentration of F in the drinking *Fluoride Geochemistry and Health Hazards: A Case Study DOI: http://dx.doi.org/10.5772/intechopen.105156*

water. The acceptable concentration of urine F is 1.0 mg/L [35]. The results of the urine samples of current study area showed that minimum and maximum urinary F concentrations are 1.2 and 16.2 mg/l, while the groundwater samples (mean of both seasons) show 0.42–14.2 mg/l, respectively (**Table 8**). The urine samples were further classified as low (<0.6 mg/L), intermediate (0.6–1.5 mg/L) and high (>1.5 mg/L) based on mean F− content in the groundwater.

The minimum and maximum of urine F concentrations among the low (<0.6 mg/L), intermediate (0.6–1.5 mg/L) and high (>1.5 mg/L) F areas ranged from 0.45 to 1.2 mg/l, 1.4 to 4.2 mg/L and 2.1 to 16.2 mg/L respectively. The corresponding mean values were 1.2 mg/L, 2.52 mg/L, and 4.93 mg/L respectively (**Figure 7**). The lowest urine concentration (1.2 mg/L) is observed in low F areas (with F < 0.6 mg/L in water) and the highest urine concentration (16.2 mg/L) was observed among areas of high F concentration (>1.5 mg/L) in water. This was also supported by excellent positive correlation between the urinary and groundwater F (**Figure 8**). The mean F concentration in urine has enhanced from low to high F groups (**Table 8**). The urine F content even in the low F areas exceeded the acceptable concentrations of 1.0 mg/L. This shows that the groundwater consumed by the individuals was the main causative factor for fluorosis hazard.


#### **Table 8.**

*Data\* on different F− concentrations in groundwater and urine (mg/L).*

**Figure 7.** *Results of F− content in urine and groundwater\* samples of study area.*

**Figure 8.** *Mean F− content in groundwater vs urine fluoride.*
