**3. Sampling and analytical methods**

A total of 22 boreholes were sampled for chemical analysis, 15 samples collected from the BouHafna aquifer and 7 samples from the Haffouz aquifer. The physicochemical parameters such as Temperature (T°C), pH, and electrical conductivity (EC) were measured directly in situ using portable meters. Groundwater samples were analyzed for major ions in the laboratory of Radio-Analyses and Environment of the school of engineers of Sfax, Tunisia. Major cation concentrations were determined by Waters Ion chromatograph using IC-PakTM CM = D columns. Major anion concentrations were measured using a Metrohm ion chromatograph equipped with CI SUPER-SEP columns. The analysis of bicarbonate was undertaken by titration to the methyl orange endpoint.

**4.2. Water type**

**4.3. Correlation matrix**

samples have the same Ca-Mg-HCO<sup>3</sup>

BouHafna aquifer, which are distinguished by Ca-Mg-SO<sup>4</sup>

parameters to the groundwater mineralization [15, 16] (**Table 2**).

solution. The strong and positive relationship between Ca and SO<sup>4</sup>

The correlation matrix of 12 parameters (Cl, NO<sup>3</sup>

anhydrite. The moderate correlation between NO<sup>3</sup>

**Figure 5.** Piper diagram of Haffouz and BouHafna aquifers.

The data plotted in the Piper diagram [14] show that Haffouz and BouHafna groundwater

and T°C) was computed in order to calculate the contribution degree of each hydrochemical

Mg, and Ca versus TDS (>0.9), providing insight into the large contribution of these ions to BouHafna and Haffouz groundwater salinization. There is well positive correlation between Na and Cl (r = 0.84), indicating the same origin of these elements likely related to the halite dis-

ions derive from the same origin probably in relation with the dissolution of gypsum and/or

by an anthropogenic effect related to the pollution through return flow of irrigation water.

Overall groundwater samples display positive and strong correlations between Cl, SO<sup>4</sup>

, SO<sup>4</sup>

Hydrochemical Investigation and Quality Assessment of Groundwater in the BouHafna-Haffouz…

, HCO<sup>3</sup>

water-type, except for some samples collected from

water-type (**Figure 5**).

, Na, K, Mg, Ca, TDS, EC, pH,

http://dx.doi.org/10.5772/intechopen.72173

(r = 0.98) suggests that these

and the majority of ions can be explained

, Na,

97
