Hydrogeochemistry study and groundwater quality assessment in the north of Isfahan, Iran

Abstract

This study presents the groundwater quality assessment in the north of Isfahan, Iran. In the study area, assessment and measurement of groundwater hydrochemical parameters such as pH, total dissolved solids (TDS), electrical conductivity (EC), sodium absorption ratio (SAR), total hardness, major cations (K, Na, Ca and Mg) and major anions (Cl, [Formula: see text] and [Formula: see text]) concentrations were performed. Accordingly, the 66 water samples from different locations were collected during April and May 2015. Water samples collected in the field were analyzed in the laboratory for cations and anions using the standard methods. In this research, the analytical results of physiochemical parameters of groundwater were compared with the standard guideline values as recommended by the world health organization (WHO) for drinking and public health purposes. The pH values of groundwater samples varied from 7.05 to 8.95 with a mean of 7.78, indicating a neutral to slightly alkaline water. TDS values showed that 14% of the samples exceeds the desirable limit given by WHO. EC values varied from 213 to 4320 µS/cm, while 23% of the samples were more than the standard limit. Gibbs diagram had shown that 90% of the samples in the study area fall in the rock weathering zone, and this means that chemical weathering of rock-forming minerals is the main factor controlling the water chemistry in the study area. Irrigation suitability and risk assessment of groundwater are evaluated by measuring EC, %Na, SAR and RSC. According to the dominant cations and anions, five types of water were identified in the water samples: Ca-HCO, Ca-SO, Na-Cl, Na-HCO and Na-SO. The results show that the majority of samples (30 samples, 45%) belongs to the mixed Na-SO water type. Correlation analysis and principal component analysis was used to identify the relationship between ions and physicochemical parameters. Results indicated that 18 stations of the study area had the best quality and can be used for irrigation and drinking purposes in the future.

Groundwater quality evaluation of Shiraz City, Iran using multivariate and geostatistical techniques

“…Cl, SO 4 , hardness, TDS and SAR showed correlation with each other. The correlation of EC and TDS is attributed by the fact that dissolved constituents cause enhanced ionic content and EC content [39]. The correlations results of different ions showed that these ions involve diverse physical as well as chemical processes such as oxidation/reduction reactions as well as ion exchange in groundwater aquifers, indicating that similar factor have strong influence on them [40,41].…”

Anthropogenic Effects on Hydrogeochemical Characterization of the Shallow Groundwater in an Arid Irrigated Plain in Northwestern China

“…All samples were clustered in the upper-middle part of the Gibbs plots ( Figure 3), suggesting that evaporation-crystallization was the primary mechanism controlling groundwater chemistry in both years, followed by rock weathering as a secondary process. Evaporation greatly increases the concentrations of ions formed by chemical weathering [43,44]; this is a key process in the semi-arid study area: it can increase salinity by increasing Na + and Cl − content, resulting in increased TDS [40]. The concentrations of Cl − and HCO − 3 were mostly affected by rock weathering, whereas the evaporation-crystallization process was the major factor leading to higher contents of Na + and Cl − ions (Figure 3a,b).…”

“…The Pearson's correlation matrices showed that Na + , SO 2− 4 , and Cl − concentrations had strongly positive correlations in both 2004 and 2014 ( Table 2). This generally high correlation between sodium and chloride has been widely used in arid and semi-arid regions to identify salinity mechanisms such as the dissolution of halite deposits and evaporation [39,40]. The coexistence of Na + and SO 2− 4 may be attributed to dissolution of mirabilite or the use of gypsum and sodium sulfate fertilizer.…”

Investigation of Groundwater Contamination and Health Implications in a Typical Semiarid Basin of North China

“…A correlation coefficient close to +1 or −1 indicates strong positive or negative correlation between the two parameters, while coefficients close to 0 demonstrate a weak correlation [13]. PCA is a useful mathematical method to reduce the dimensionality of the dataset in order to identify the key mechanisms influencing/controlling groundwater chemistry without losing important information [40][41][42]. This method can transform the correlated observations to uncorrelated quantities (principal components) based on an orthogonal transformation.…”