# Assessment of Physicochemical and Bacteriological Parameters in the Angads Aquifer (Northeast Morocco): Application of Principal Component Analysis and Piper and Schoeller–Berkaloff Diagrams

Authors: L. Taoufiq; I. Kacimi; M. Saadi; N. Nouayti; N. Kassou; T. Bouramtane; K. El-Mouhdi
Journal: Applied and Environmental Soil Science
 (2023)

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## Abstract

Groundwater is a vital resource and a development lever for many countries, including Morocco. To develop these resources, mineralogical and hydrogeochemical studies as well as a bacteriological study were carried out on the groundwater of the Angads aquifer, which is located in the northeast of Morocco to highlight the processes at the origin of mineralization, their quality for human consumption and irrigation, as well as the hydrogeochemical facies of these waters. To do this, a multivariate statistical analysis using principal component analysis, varimax rotation of factors, and hierarchical ascending classification were conducted for all the groundwater samples of the Angads aquifer in Oujda. The main results revealed that these waters present faecal contamination by faecal and total coliforms and faecal streptococci. And another one by nitrates due to the high values of NO3−, as well as the mineralization of these waters is controlled by the nature of the geological formations crossed and the residence time in the aquifer, which is confirmed by the presence of ions such as Cond, HCO3−, Ca2+, Mg2+, and SO42−. Concerning the quality of the groundwater, according to Moroccan standards and the World Health Organization, the results show that they are generally unsuitable for human consumption and irrigation. Two diagrams were used to study the facies: Piper and Schoeller–Berkaloff. The results show that these waters are highly mineralized, with the chloride and sulphate calcic and magnesian facies dominating with 89.47%. To protect this vital resource, sustainable management actions must be implemented, in particular, to reduce the use of pesticides, control the use of fertilizers, and clean up and purify the groundwater.


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## Body

## 1. Introduction

All over the world, the pressure to use water resources, and in particular groundwater, is increasing due to deteriorating water quality and growing demand [1]. In Morocco, due to prolonged periods of drought, water availability is very limited and likely to decrease considerably in the long term; as a result, renewable water resources per capita have decreased from 800 m3 in 1990 to 400 m3 in 2020, placing Morocco in the category of chronically water-stressed countries [2]. Indeed, the composition of groundwater reflects interactions with vegetation cover, the characteristics of the soil through which it flows, inputs from the atmosphere, the presence of industrial or agricultural activities, and the lithology of the geological formations that host the aquifers [3, 4]. Moreover, groundwater is traditionally the water resource for human consumption and irrigation, as it is less polluting than surface water [5, 6]. The degradation of their quality by various sources of pollution, including untreated wastewater discharges, use of fertilizers and pesticides, and uncontrolled discharges of solid wastes pose a threat to water resources and ecosystems and thus a risk to human food and irrigation. Unfortunately, the presence of public dumps near these water resources increases the risk of pollution and transmission of vector-borne diseases and threatens human and environmental health [7, 8]. Hence, the need for physicochemical and bacteriological analyses, which constitute a reliable source of information to characterize the impact of human, agricultural, and industrial activities and of the different landscape units, as well as the origin of mineralization [9]. Indeed, the presence of Na+, K+, and HCO3− reflects the nature of the minerals encountered during infiltration and the nature of the rocks crossed, for the high contents of Cl−, and SO42− indicate leachate wastewater, and the high content of NO3− is related to the amounts of nitrogen fertilizer associated with intensive crops and livestock [10]. In addition, the presence of bacteria such as total coliforms (TCs), faecal coliforms (FCs), and faecal streptococci (FS) reveals contamination of faecal origin. In the Oriental region, previous studies have determined some physicochemical parameters of groundwater and others have assessed its quality. But this work presents methods and tools used for the first time at the level of the Angads groundwater, with new sampling points, and new physicochemical parameters, which implies new results to define the current state of this groundwater and to help decision-makers take adequate measures to improve and preserve it.


## 2. Materials and Methods

### 2.1. Presentation of the Study Area

The present study was carried out in September 2020 on the Angads aquifer in the northeast of Morocco (Figure1). The aquifer extends up to 460 km2 [11], it is bounded in the South by Jbel Hamra, in the North by the Beni Snassen chain, in the West by Jbels Megrez and Tarraza [11] and in the East, it extends into Algeria up to the Mernia plain [12]. From a geological point of view (Figure 1), the study area is characterised by lateral heterogeneity, it is mainly composed of more or less calcareous-encrusted soils, more or less clayey silts, and volcanic rocks of the Plio-Quaternary. This area is marked by the presence of a flexure, which divides the study area into two units: the Southern Angads (260 km2) and the Northern Angads (200 km2) [12, 13]. In addition, the study area (Figure 1) is characterised by two-bowl geometry on either side of this flexure [13].Figure 1
Geological map of the Angads aquifer.


### 2.2. Study Design and Sampling

The increasing importance is given to water in Eastern Morocco and the lack of mineralogical and hydrogeochemical study, as well as the study of its quality for human food and irrigation in this region. The present study was carried out in the Angads aquifer, which is located in the northeast of Morocco, to highlight the processes at the origin of mineralization, to determine their quality for human consumption and irrigation, as well as to define the hydrogeochemical facies of this groundwater.For this purpose, groundwater samples were taken at nineteen sampling points (Figure1), distributed as follows: (a) seventeen wells, including six wells upstream and downstream of the wastewater treatment plant (WWTP), one well located close to and the other downstream of the Oujda public dumping site, for the other wells are distributed throughout the study area and (b) two boreholes whose choice was explained by the high frequency of their use by the rural population. The geographical coordinates of the wells were obtained using a GPS (GARMIN–GPSMAP64s).In addition, two samples were taken per well for all sampling points. The samples taken were placed in polyethylene bottles with a capacity of 1.5 litres. These bottles were washed beforehand with distilled water and three times with groundwater. The samples were transported in coolers at 4°C to the laboratory. Hydrogeochemical and bacteriological parameters were determined in situ and the laboratory according to the protocols described by Jean Rodier [14]. These parameters are (a) physical parameters, in particular electrical conductivity (Cond), temperature (T°), and hydrogen potential (pH); (b) chemical parameters are mainly bicarbonate (HCO3−), chloride (Cl−), sodium (Na+), manganese (Mn2+), potassium (K+), ferrous ion (Fe2+) sulphate (SO42−), nitrate (NO3−), magnesium (Mg2+), calcium (Ca2+), nitrogen dioxide (NO2−), ammonium (NH4+), and permanganate index (PI); and (c) bacteriological parameters such as total coliforms (TCs), faecal coliforms (FCs), and faecal streptococci (FS).


### 2.3. Analysis Methods and Data Processing

All the water samples collected were subjected to hydrogeochemical, physicochemical, and bacteriological analyses. Then, the data obtained were subjected to descriptive statistics using mean, minimum, maximum, and standard deviation values and multivariate statistics based on principal component analysis (PCA), varimax rotation, and hierarchical ascending classification (HAC) to determine the different mechanisms of groundwater mineralization. Indeed, the variables are positively correlated when close to 1 and negatively correlated when close to −1, using the statistical software R.On the other hand, the hydrogeochemical analysis was represented based on two diagrams: (a) the first is the Piper diagram which is a representation of chemical facies based on a graphical distribution of major anions (HCO3−, Cl−, SO42−, and NO3−) and major cations (Ca2+, Mg2+, Na+, and K+) [10]. This diagram is composed of two triangles representing the anionic facies and the cationic facies and a diamond synthesizing the overall facies [5] and (b) the second is the Schoeller–Berkaloff diagram, which represents the chemical facies of several waters [15]. Thus, the cartographic representation of the data was conducted using the geographic information system (GIS).


## 2.1. Presentation of the Study Area

The present study was carried out in September 2020 on the Angads aquifer in the northeast of Morocco (Figure1). The aquifer extends up to 460 km2 [11], it is bounded in the South by Jbel Hamra, in the North by the Beni Snassen chain, in the West by Jbels Megrez and Tarraza [11] and in the East, it extends into Algeria up to the Mernia plain [12]. From a geological point of view (Figure 1), the study area is characterised by lateral heterogeneity, it is mainly composed of more or less calcareous-encrusted soils, more or less clayey silts, and volcanic rocks of the Plio-Quaternary. This area is marked by the presence of a flexure, which divides the study area into two units: the Southern Angads (260 km2) and the Northern Angads (200 km2) [12, 13]. In addition, the study area (Figure 1) is characterised by two-bowl geometry on either side of this flexure [13].Figure 1
Geological map of the Angads aquifer.


## 2.2. Study Design and Sampling

The increasing importance is given to water in Eastern Morocco and the lack of mineralogical and hydrogeochemical study, as well as the study of its quality for human food and irrigation in this region. The present study was carried out in the Angads aquifer, which is located in the northeast of Morocco, to highlight the processes at the origin of mineralization, to determine their quality for human consumption and irrigation, as well as to define the hydrogeochemical facies of this groundwater.For this purpose, groundwater samples were taken at nineteen sampling points (Figure1), distributed as follows: (a) seventeen wells, including six wells upstream and downstream of the wastewater treatment plant (WWTP), one well located close to and the other downstream of the Oujda public dumping site, for the other wells are distributed throughout the study area and (b) two boreholes whose choice was explained by the high frequency of their use by the rural population. The geographical coordinates of the wells were obtained using a GPS (GARMIN–GPSMAP64s).In addition, two samples were taken per well for all sampling points. The samples taken were placed in polyethylene bottles with a capacity of 1.5 litres. These bottles were washed beforehand with distilled water and three times with groundwater. The samples were transported in coolers at 4°C to the laboratory. Hydrogeochemical and bacteriological parameters were determined in situ and the laboratory according to the protocols described by Jean Rodier [14]. These parameters are (a) physical parameters, in particular electrical conductivity (Cond), temperature (T°), and hydrogen potential (pH); (b) chemical parameters are mainly bicarbonate (HCO3−), chloride (Cl−), sodium (Na+), manganese (Mn2+), potassium (K+), ferrous ion (Fe2+) sulphate (SO42−), nitrate (NO3−), magnesium (Mg2+), calcium (Ca2+), nitrogen dioxide (NO2−), ammonium (NH4+), and permanganate index (PI); and (c) bacteriological parameters such as total coliforms (TCs), faecal coliforms (FCs), and faecal streptococci (FS).


## 2.3. Analysis Methods and Data Processing

All the water samples collected were subjected to hydrogeochemical, physicochemical, and bacteriological analyses. Then, the data obtained were subjected to descriptive statistics using mean, minimum, maximum, and standard deviation values and multivariate statistics based on principal component analysis (PCA), varimax rotation, and hierarchical ascending classification (HAC) to determine the different mechanisms of groundwater mineralization. Indeed, the variables are positively correlated when close to 1 and negatively correlated when close to −1, using the statistical software R.On the other hand, the hydrogeochemical analysis was represented based on two diagrams: (a) the first is the Piper diagram which is a representation of chemical facies based on a graphical distribution of major anions (HCO3−, Cl−, SO42−, and NO3−) and major cations (Ca2+, Mg2+, Na+, and K+) [10]. This diagram is composed of two triangles representing the anionic facies and the cationic facies and a diamond synthesizing the overall facies [5] and (b) the second is the Schoeller–Berkaloff diagram, which represents the chemical facies of several waters [15]. Thus, the cartographic representation of the data was conducted using the geographic information system (GIS).


## 3. Results

### 3.1. Physicochemical and Bacteriological Analyses

The results of the physicochemical and bacteriological parameters of the groundwater from nineteen sampling points of the Angads aquifer (see Table1) show that the pH varies from 6.95 to 7.55 with an average of 7.20 and a standard deviation of 0.20. The Cond varies from 10355 µS cm−1 to 986 µS cm−1, with an average of 2463 µS cm−1 and a standard deviation of 2172 µS cm−1. For cations such as Na+ the values vary from 44 mg/l to 1227 mg/l, with a mean of 215 mg/l and a standard deviation of 265.6, the K+ values vary between 0.72 mg/l and 15.30 mg/l with a mean of 6.38 mg/l and a standard deviation of 146.62. Then for anions such as Cl− the values vary between 172 mg/l and 3597 with a mean of 607 mg/l and a standard deviation of 788.9. While for NO3−, the values vary between 5.4 mg/l and 134 mg/l with a mean of 50.6 mg/l and a standard deviation of 39.80. For SO42− the values vary between 49 mg/l and 1395 mg/l, with an average of 219 mg/l and a standard deviation of 323.5.Table 1
Physicochemical and bacteriological data of the Angads groundwater in 2020.
Sample pointsParametersUnitsAverageMaximumMinimumStandard deviation1pH—7.197.556.950.192T°°C21.3923.619.71.183Cond(µS/cm)2463103559862171.784PI(mg/l)1.949.330.653.675NH4+(mg/l)0.160.670.020.256Na+(mg/l)215.451226.543.7265.587K+(mg/l)6.3715.30.71146.628Ca2+(mg/l)162.8860172146.629Mg2+(mg/l)152.2169354.67154.9110Fe2+(mg/l)1.4117.70.064.2311Mn2+(mg/l)0.270.460.070.2712Cl−(mg/l)607.233597172788.8713NO2−(mg/l)16.231760.01152.9914NO3−(mg/l)50.621345.3839.815SO42−(mg/l)219.42139549323.4616HCO3−(mg/l)383.98811.3250.1138.2217TC(UFC/100 ml)4668.5236000011317.8418FC(UFC/100 ml)557.89480001399.3119FS(UFC/100 ml)1130.63900002505.68From a bacteriological point of view, our results revealed that TCs vary between 36000 FCU/100 ml and 0 FCU/100 ml, and an average of 4669 FCU/100 ml and a standard deviation of 11317. FCs ranged from 4800 FCU/100 ml to 0 FCU/100 ml, with a mean of 558 FCU/100 ml and a standard deviation of 1399. The FSs vary between 9000 FCU/100 ml and 0 FCU/100 ml, with a mean of 1131 FCU/100 ml and a standard deviation of 2505.


### 3.2. Principal Component Analysis

Principal component analysis was carried out on nineteen physicochemical and bacteriological parameters (Cond, T°, pH, HCO3−, Cl−, Na+, Mn2+, K+, Fe2+, SO42−, NO3−, Mg2+, Ca2+, NO2−, NH4+, PI, TC, FC, and FS). In fact, the relationship between the variables was taken two by two and the correlation coefficients between these different variables were given by the correlation matrix (Table 2). The latter shows that there is a significant correlation between the variables Na+∗ Cond (0.926), Ca2+∗ Cond (0.939), Mg2+∗ Cond (0.977), Cl−∗ Cond (0.992), Mg2+∗ Na+ (0.841), Cl−∗ Na+ (0, 927), Mg2+∗ Ca2+ (0.967), Cl−∗ Ca2+ (0.923), Cl−∗ Mg2+ (0.972), SO42−∗ Cond (0.990), SO42−∗ Na+ (0.910), SO42−∗ Ca2+ (0.948), SO42−∗ Mg2+ (0.980), SO42−∗ Cl− (0.984697), and FS ∗ FC (0.985). There is also a lower degree of correlation between variables K+∗ Cond (0.637), K+∗ Na+ (0.634), Ca2+∗ K+ (0.533), Mg2+∗ K+ (0, 596), Mg2+∗ K+ (0.596), Mn2+∗ NH4+ (0.503), Cl−∗ K+ (0.652), NO2−∗ NH4+ (0.616), T° ∗ pH (0.532), SO42−∗ K+ (0.590), and TC ∗ Fe2+ (0.617).Table 2
Correlation matrix of physicochemical and bacteriological parameters of the Angads aquifer in September 2020.
pHCondNH4+Na+K+Ca2+Mg2+Fe2+Mn2+Cl−No2−No3−HCO3−T°SO42−TCFCFSPIpH1.000000Cond−0.3494331.000000NH4+−0.038416−0.2372211.000000Na+−0.2459660,926950−0.2081421.000000K+−0.0310500.6375420.0743400.6348101.000000Ca2+−0.4107540.939514−0.2007580.7538050.5330071.000000Mg2+−0.4199840.977477−0.2672400.8414700.5960360.9677551.000000Fe2+−0.168628−0.017464−0.178001−0.0188780.199262−0.0181880.0037811.000000Mn2+0.128053−0.6126450.503143−0.668514−0.475745−0.493472−0.5678530.0332121.000000Cl−−0.3372620.992163−0.2494110.9275180.6527580.9233400.972695−0.016476−0.6140891.000000No2−0.166032−0.3022360.616978−0.164000−0.088350−0.362559−0.344285−0.0382730.306983−0.2902471.000000No3−−0.1850480.0149410.132153−0.1488000.0629990.1738770.0550650.069138−0.054568−0.078582−0.1816501.000000HCO3−−0.2876220.0578360.0300320.160462−0.164073−0.0284900.0171860.008431−0.188020−0.0308800.0552780.3516271.000000T°0.532687−0.3354620.259581−0.262139−0.019809−0.372653−0.3786290.0589850.314832−0.2966020.447351−0.229618−0.4617371.000000SO42−−0.4113850.990250−0.2451620.9101900.5909790.9480410.980140−0.000581−0.6045270.984697−0.2836830.0129120.063145−0.3765681.000000TC−0.194120−0.066263−0.469473−0.116252−0.069725−0.023310−0.0331670.617142−0.201175−0.056931−0.293838−0.106646−0.023624−0.098594−0.0652521.000000FC0.102079−0.093659−0.540243−0.144069−0.235072−0.031768−0.0335590.3926450.041121−0.061622−0.339444−0.341956−0.088576−0.085273−0.0740910.5765721.000000FS0.122356−0.033027−0.626527−0.082360−0.1996220.0227670.0236710.341605−0,0.101184−0.005456−0.399371−0.295805−0.050779−0.143241−0.0137640.5692550.9854241.000000PI0.286965−0.139361−0.155104−0.136211−0.280653−0.100359−0.093699−0.1357500.074440−0.111212−0.034465−0.281780−0.0685310.051655−0.102776−0.1153170.4670930.4791641.000000In contrast, Figure2 shows the percentage variance for each principal component. Indeed, the analysis shows that the first principal component (F1) represents 37.22% of the variance expressed, followed by the second principal component (F2) with 19.29% of the variance expressed, then by the third principal component (F3) with 11.00% of the variance expressed, and then by the fourth principal component (F4) with 08.38% of the variance expressed. Thus, F1, F2, F3, and F4 constitute the first four principal components, with 75.89% of the variance expressed.Figure 2
The percentage of variance expressed by each principal component of the Angads aquifer in September 2020.The distribution of nineteen physicochemical and bacteriological parameters on the factorial plane (F1-F2) (Figure 3) shows that the first principal component (F1) was positively correlated with pH, Mn2+, T°, NO2−, and NH4+ and negatively correlated with Mg2+, Ca2+, SO42−, K+, Na2+, and Cond, Cl−. Indeed, the chemical elements NO2− and Mn2+ are present in the soil and are related to NH4+, since NO2− results from the nitrification of NH4+, while Mn2+ is often present in groundwater in association with NH4+. It can be deduced that F1 is considered as an axis reflecting soil rainfall and residence time in the aquifer. On the other hand, the second principal component (F2) was positively correlated with the chemical parameters K+, NO3−, NO2−, and NH4+, and negatively correlated with the bacteriological parameters FC, TC, and FS, as well as with the chemical parameter Fe2+. It is deduced that F2 is considered as an axis reflecting the agricultural pollution due to the use of nitrogenous fertilizers.Figure 3
Distribution of parameters on the factorial plane (F1-F2) of the Angads aquifer in September 2020.The third principal component (F3) with 11.00% of the variance expressed, shows a positive correlation with Cond, pH, T°, PI, K+, Na2+, and Cl− and a negative correlation with Fe2+, TC, NO3−, and HCO3− (Figure 4). Indeed, the main component F3 is considered as an axis reflecting the mineralization of water related to water-rock contacts.Figure 4
Distribution of parameters on the factorial plane (F1–F3) of the Angads aquifer in September 2020.The fourth principal component (F4), with 08.38% of the variance expressed, was negatively correlated with T°, Fe2+, TC, and K+ and positively correlated with pH, PI, and HCO3− (Figure 5). This explains that F4 expresses the mineralization of water related to water-rock contacts.Figure 5
Distribution of parameters on the factorial plane (F1–F4) of the Angads aquifer in September 2020.


### 3.3. Appropriate Rotation of Factors by Varimax

For a better analysis of the factors, we use an appropriate rotation of the factors by varimax while keeping the same physicochemical and bacteriological parameters, as well as the sampling points. Four main components were detected, the first one is Factor 1 with 47.28% of the expressed variance, the second one is Factor 2 with 16.65% of the expressed variance, and the third one is Factor 3 with 11.57% of the expressed variance, and the fourth one is Factor 4 with 6.71% of the expressed variance the results of this analysis are presented in Figure6.Figure 6
The distribution of the nineteen physicochemical and bacteriological parameters on the factorial plane (Factor 1-Factor 2), (Factor 1–Factor 3), and (Factor 1–factor 4) by the varimax rotation in the Angads aquifer in 2020.
(a)(b)(c)The distribution of nineteen physicochemical and bacteriological parameters on the factorial plane (Factor 1-Factor 2), (Factor 1–Factor 3), and (Factor 1–Factor 4) (Figure6) shows that the first principal component (Factor 1) was positively correlated with Cond, PI, Ca2+, Na+, Mg2+, Fe2+, Mn2+, and Cl−, and negatively correlated with T°, pH, NO2−, NO3−, HCO3−, TC, and FC. The presence of these ions is associated with the dissolution of minerals that may be formed by the dissolution of evaporitic formations and by the evaporation of salt-laden water.Furthermore, the second principal component (Factor 2) was positively correlated with the physicochemical parameters T°, NO2−, NO3−, and K+ and negatively correlated with the bacteriological parameters FC, TC, and FS. These ions are mostly of anthropogenic origin and their presence in groundwater is either due to the discharge of wastewater or the leaching of fertilizers. While the third principal component (Factor 3) was positively correlated with PI, NH4+, NO3−, HCO3−, Ca2+, PI, and SO42−. But, Cond negatively correlated with physicochemical parameters which are T° and pH (Figure 6). The presence of these ions is attributed to the degradation of organic matter by microorganisms in the superficial soil formations, with the production of CO2 to be carried to depth by groundwater. However, the fourth principal component (Factor 4) was positively correlated with NH4+, NO3−, pH, HCO3−, TC, FC, FS, K+, Na+, and PI, and negatively correlated with T°. These ions are mainly of anthropogenic origin and their presence in groundwater is explained by the leaching of applied fertilizers and by contamination by faecal pollution germs.


### 3.4. Hierarchical Ascending Classification

Hierarchical ascending classification (HAC) aims to classify individuals by matching them to the least dissimilarity, for a set of variables. The result of HAC is presented in the form of dendrograms [15]. The closest individuals are grouped based on a dendrogram and linked by an “aggregation criterion.” They constitute a type. The dendrogram connects subjects by least dissimilarity, and only the direction of the variables can reveal the unifying character of the types. The CAH used here is that of Ward’s method. It has the particularity of recalculating the aggregation indices for each stage of the classification [15].Figure7 shows the hierarchical tree constructed with the rescaled class combination distance and the Ward criterion for nineteen sample points distributed over the entire area. Indeed, if the cut-off level is at distance 5, two classes can be distinguished. The first class includes the closest points 1, 2, 4.5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 18, and 19 which are homogeneous with points 3. This class is characterised by high contents of physicochemical parameters, in particular Cond, Na+, Ca2+, Mg2+, Cl−, NO2−, NO3−, HCO3−, and SO42−, which reach, respectively, up to 10355 µS/cm, 1226, 5 mg/l, 601 mg/l, 693 mg/l, 3597 mg/l, 176 mg/l, 134 mg/l, 811, 3 mg/l, and 1395 mg/l. On the other hand, the second class includes points 12 and 17 which have high levels of TC (36000/100 ml), FC (4800/100 ml), and FS (9000/100 ml).Figure 7
Dendrogram of nineteen Angads groundwater sample points.The results of the hierarchical tree constructed with the combined distance of the resized classes and the Ward criterion of nineteen physicochemical and bacteriological parameters (Figure8) reveal that from the distance cut-off level 5, three classes can be distinguished. The first class includes physicochemical parameters such as NH4+, Mn2+, PI, Fe2+, pH, K+, T°, NO2−, NO3−, Mg2+, Ca2+, Na+, SO42−, HCO3−, and Cl− which are the closest and are homogeneous with Cond, this class realizes that the mineralization of groundwater is controlled by the nature of the geological formations present in the area. The other two classes include bacteriological parameters, namely FC and FS in the second class, and TC in the third class, indicating that the second class groundwater is contaminated by faecal matter, while the third class indicates that the groundwater may be contaminated by more harmful microorganisms.Figure 8
Dendrogram of nineteen physicochemical and bacteriological parameters of the Angads groundwater.


### 3.5. Hydrogeochemical Analysis

The results of the hydrogeochemical analysis using the Piper diagram (Figure9) show that the chemical parameters (cation and major anion) of the groundwater from nineteen sampling points in the Angads aquifer were processed using the Piper diagram. This diagram shows the hydrogeochemical facies. The results of which show two types of facies: one chloride and sulphate calcic and magnesian at sampling points 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, and 19, occupying 89.47%, and the other is chloride sodium and potassium facies at both points 7 and 10 with a percentage of 10.52%.Figure 9
Piper diagram of Angads groundwater in September 2020.The results of the Schoeller–Berkaloff diagram analysis (Figures10(a) and 10(b)) of nineteen sampling points, of the Angads groundwater, reveal that these waters show identical profiles in the majority of the sampling points. Except for the four points 7, 8, 10 (Figure 10(a)), and 15 (Figure 10(b)) which show high values of some chemical elements, namely, point 7 in Na+, K+, Cl−, HCO3−, and CO3−, for point 8 in Mg2+ and Cl−, for point 10 in Na+, K+, and Cl− and for point 15 in Mg2+, Na+, K+, and Cl−.Figure 10
(a, b) Schoeller–Berkaloff diagram of Angads groundwater in September 2020.
(a)(b)


### 3.6. Assessment of Water Quality for Human Consumption and Irrigation

To determine whether the groundwater from nineteen sampling points in the Angads aquifer is intended for human consumption and irrigation, hydrogeochemical and bacteriological parameters were compared with Moroccan and World Health Organization standards (Table3). The results reveal that the parameters NO3−, Cond, Cl−, Fe2+, Mn2+, and HCO3− exceed Moroccan and WHO standards for human food and irrigation, with the highest values recorded in wells located downstream of the wastewater treatment plant and the other near the dump. In these wells, these parameters reach up to NO3− (134 mg/l), Cond (10355 µS/cm), Cl− (3597 mg/l), Fe2+ (17.7 mg/l), Mn2+ (0.466 mg/l), HCO3− (811 mg/l), instead of NO3− (50 mg/l), Cond (2700 µs/cm), Cl− (750 mg/l), Fe2+ (5 mg/l), Mn2+ (0.2 mg/l), and HCO3− (518 mg/l).Table 3
The Moroccan food and irrigation standards and the WHO guidance values 2011.
Physicochemical and bacteriological parametersUnit of measurementWHO guide values 2011Moroccan standards for human foodWater quality standards for irrigationT°°CAcceptable35pH6.5–8.56.5 < pH < 8.56.5 à 8.4CondµS cm−1400270012NH4+mg.L−11.50.5—Na+mg.L−1200——K+mg.L−112——Ca2+mg.L−1ND——Mg2+mg.L−1ND——Fe2+mg.L−10.30.3—Mn2+mg.L−10.50.50.2Cl−mg.L−1250750—NO2−mg.L−130.5—NO3−mg.L−15050—HCO3−mg.L−1ND—518SO42−mg.L−1250400250TCufc/100 ml)>1/100 ml0/100 ml—FCufc/100 ml—0/100 ml1000/100 mlFSufc/100 ml>1/100 ml——PImg.L−1———The comparison of the FC, TC, and FS values of these groundwater with the Moroccan standards for human food and irrigation as well as the World Health Organization. The highest values were recorded in wells located downstream of the wastewater treatment plant and others near and downstream of the Oujda public dump, reaching up to FC (36000/100 ml), TC (4800/100 ml), and FS (9000/100 ml).


## 3.1. Physicochemical and Bacteriological Analyses

The results of the physicochemical and bacteriological parameters of the groundwater from nineteen sampling points of the Angads aquifer (see Table1) show that the pH varies from 6.95 to 7.55 with an average of 7.20 and a standard deviation of 0.20. The Cond varies from 10355 µS cm−1 to 986 µS cm−1, with an average of 2463 µS cm−1 and a standard deviation of 2172 µS cm−1. For cations such as Na+ the values vary from 44 mg/l to 1227 mg/l, with a mean of 215 mg/l and a standard deviation of 265.6, the K+ values vary between 0.72 mg/l and 15.30 mg/l with a mean of 6.38 mg/l and a standard deviation of 146.62. Then for anions such as Cl− the values vary between 172 mg/l and 3597 with a mean of 607 mg/l and a standard deviation of 788.9. While for NO3−, the values vary between 5.4 mg/l and 134 mg/l with a mean of 50.6 mg/l and a standard deviation of 39.80. For SO42− the values vary between 49 mg/l and 1395 mg/l, with an average of 219 mg/l and a standard deviation of 323.5.Table 1
Physicochemical and bacteriological data of the Angads groundwater in 2020.
Sample pointsParametersUnitsAverageMaximumMinimumStandard deviation1pH—7.197.556.950.192T°°C21.3923.619.71.183Cond(µS/cm)2463103559862171.784PI(mg/l)1.949.330.653.675NH4+(mg/l)0.160.670.020.256Na+(mg/l)215.451226.543.7265.587K+(mg/l)6.3715.30.71146.628Ca2+(mg/l)162.8860172146.629Mg2+(mg/l)152.2169354.67154.9110Fe2+(mg/l)1.4117.70.064.2311Mn2+(mg/l)0.270.460.070.2712Cl−(mg/l)607.233597172788.8713NO2−(mg/l)16.231760.01152.9914NO3−(mg/l)50.621345.3839.815SO42−(mg/l)219.42139549323.4616HCO3−(mg/l)383.98811.3250.1138.2217TC(UFC/100 ml)4668.5236000011317.8418FC(UFC/100 ml)557.89480001399.3119FS(UFC/100 ml)1130.63900002505.68From a bacteriological point of view, our results revealed that TCs vary between 36000 FCU/100 ml and 0 FCU/100 ml, and an average of 4669 FCU/100 ml and a standard deviation of 11317. FCs ranged from 4800 FCU/100 ml to 0 FCU/100 ml, with a mean of 558 FCU/100 ml and a standard deviation of 1399. The FSs vary between 9000 FCU/100 ml and 0 FCU/100 ml, with a mean of 1131 FCU/100 ml and a standard deviation of 2505.


## 3.2. Principal Component Analysis

Principal component analysis was carried out on nineteen physicochemical and bacteriological parameters (Cond, T°, pH, HCO3−, Cl−, Na+, Mn2+, K+, Fe2+, SO42−, NO3−, Mg2+, Ca2+, NO2−, NH4+, PI, TC, FC, and FS). In fact, the relationship between the variables was taken two by two and the correlation coefficients between these different variables were given by the correlation matrix (Table 2). The latter shows that there is a significant correlation between the variables Na+∗ Cond (0.926), Ca2+∗ Cond (0.939), Mg2+∗ Cond (0.977), Cl−∗ Cond (0.992), Mg2+∗ Na+ (0.841), Cl−∗ Na+ (0, 927), Mg2+∗ Ca2+ (0.967), Cl−∗ Ca2+ (0.923), Cl−∗ Mg2+ (0.972), SO42−∗ Cond (0.990), SO42−∗ Na+ (0.910), SO42−∗ Ca2+ (0.948), SO42−∗ Mg2+ (0.980), SO42−∗ Cl− (0.984697), and FS ∗ FC (0.985). There is also a lower degree of correlation between variables K+∗ Cond (0.637), K+∗ Na+ (0.634), Ca2+∗ K+ (0.533), Mg2+∗ K+ (0, 596), Mg2+∗ K+ (0.596), Mn2+∗ NH4+ (0.503), Cl−∗ K+ (0.652), NO2−∗ NH4+ (0.616), T° ∗ pH (0.532), SO42−∗ K+ (0.590), and TC ∗ Fe2+ (0.617).Table 2
Correlation matrix of physicochemical and bacteriological parameters of the Angads aquifer in September 2020.
pHCondNH4+Na+K+Ca2+Mg2+Fe2+Mn2+Cl−No2−No3−HCO3−T°SO42−TCFCFSPIpH1.000000Cond−0.3494331.000000NH4+−0.038416−0.2372211.000000Na+−0.2459660,926950−0.2081421.000000K+−0.0310500.6375420.0743400.6348101.000000Ca2+−0.4107540.939514−0.2007580.7538050.5330071.000000Mg2+−0.4199840.977477−0.2672400.8414700.5960360.9677551.000000Fe2+−0.168628−0.017464−0.178001−0.0188780.199262−0.0181880.0037811.000000Mn2+0.128053−0.6126450.503143−0.668514−0.475745−0.493472−0.5678530.0332121.000000Cl−−0.3372620.992163−0.2494110.9275180.6527580.9233400.972695−0.016476−0.6140891.000000No2−0.166032−0.3022360.616978−0.164000−0.088350−0.362559−0.344285−0.0382730.306983−0.2902471.000000No3−−0.1850480.0149410.132153−0.1488000.0629990.1738770.0550650.069138−0.054568−0.078582−0.1816501.000000HCO3−−0.2876220.0578360.0300320.160462−0.164073−0.0284900.0171860.008431−0.188020−0.0308800.0552780.3516271.000000T°0.532687−0.3354620.259581−0.262139−0.019809−0.372653−0.3786290.0589850.314832−0.2966020.447351−0.229618−0.4617371.000000SO42−−0.4113850.990250−0.2451620.9101900.5909790.9480410.980140−0.000581−0.6045270.984697−0.2836830.0129120.063145−0.3765681.000000TC−0.194120−0.066263−0.469473−0.116252−0.069725−0.023310−0.0331670.617142−0.201175−0.056931−0.293838−0.106646−0.023624−0.098594−0.0652521.000000FC0.102079−0.093659−0.540243−0.144069−0.235072−0.031768−0.0335590.3926450.041121−0.061622−0.339444−0.341956−0.088576−0.085273−0.0740910.5765721.000000FS0.122356−0.033027−0.626527−0.082360−0.1996220.0227670.0236710.341605−0,0.101184−0.005456−0.399371−0.295805−0.050779−0.143241−0.0137640.5692550.9854241.000000PI0.286965−0.139361−0.155104−0.136211−0.280653−0.100359−0.093699−0.1357500.074440−0.111212−0.034465−0.281780−0.0685310.051655−0.102776−0.1153170.4670930.4791641.000000In contrast, Figure2 shows the percentage variance for each principal component. Indeed, the analysis shows that the first principal component (F1) represents 37.22% of the variance expressed, followed by the second principal component (F2) with 19.29% of the variance expressed, then by the third principal component (F3) with 11.00% of the variance expressed, and then by the fourth principal component (F4) with 08.38% of the variance expressed. Thus, F1, F2, F3, and F4 constitute the first four principal components, with 75.89% of the variance expressed.Figure 2
The percentage of variance expressed by each principal component of the Angads aquifer in September 2020.The distribution of nineteen physicochemical and bacteriological parameters on the factorial plane (F1-F2) (Figure 3) shows that the first principal component (F1) was positively correlated with pH, Mn2+, T°, NO2−, and NH4+ and negatively correlated with Mg2+, Ca2+, SO42−, K+, Na2+, and Cond, Cl−. Indeed, the chemical elements NO2− and Mn2+ are present in the soil and are related to NH4+, since NO2− results from the nitrification of NH4+, while Mn2+ is often present in groundwater in association with NH4+. It can be deduced that F1 is considered as an axis reflecting soil rainfall and residence time in the aquifer. On the other hand, the second principal component (F2) was positively correlated with the chemical parameters K+, NO3−, NO2−, and NH4+, and negatively correlated with the bacteriological parameters FC, TC, and FS, as well as with the chemical parameter Fe2+. It is deduced that F2 is considered as an axis reflecting the agricultural pollution due to the use of nitrogenous fertilizers.Figure 3
Distribution of parameters on the factorial plane (F1-F2) of the Angads aquifer in September 2020.The third principal component (F3) with 11.00% of the variance expressed, shows a positive correlation with Cond, pH, T°, PI, K+, Na2+, and Cl− and a negative correlation with Fe2+, TC, NO3−, and HCO3− (Figure 4). Indeed, the main component F3 is considered as an axis reflecting the mineralization of water related to water-rock contacts.Figure 4
Distribution of parameters on the factorial plane (F1–F3) of the Angads aquifer in September 2020.The fourth principal component (F4), with 08.38% of the variance expressed, was negatively correlated with T°, Fe2+, TC, and K+ and positively correlated with pH, PI, and HCO3− (Figure 5). This explains that F4 expresses the mineralization of water related to water-rock contacts.Figure 5
Distribution of parameters on the factorial plane (F1–F4) of the Angads aquifer in September 2020.


## 3.3. Appropriate Rotation of Factors by Varimax

For a better analysis of the factors, we use an appropriate rotation of the factors by varimax while keeping the same physicochemical and bacteriological parameters, as well as the sampling points. Four main components were detected, the first one is Factor 1 with 47.28% of the expressed variance, the second one is Factor 2 with 16.65% of the expressed variance, and the third one is Factor 3 with 11.57% of the expressed variance, and the fourth one is Factor 4 with 6.71% of the expressed variance the results of this analysis are presented in Figure6.Figure 6
The distribution of the nineteen physicochemical and bacteriological parameters on the factorial plane (Factor 1-Factor 2), (Factor 1–Factor 3), and (Factor 1–factor 4) by the varimax rotation in the Angads aquifer in 2020.
(a)(b)(c)The distribution of nineteen physicochemical and bacteriological parameters on the factorial plane (Factor 1-Factor 2), (Factor 1–Factor 3), and (Factor 1–Factor 4) (Figure6) shows that the first principal component (Factor 1) was positively correlated with Cond, PI, Ca2+, Na+, Mg2+, Fe2+, Mn2+, and Cl−, and negatively correlated with T°, pH, NO2−, NO3−, HCO3−, TC, and FC. The presence of these ions is associated with the dissolution of minerals that may be formed by the dissolution of evaporitic formations and by the evaporation of salt-laden water.Furthermore, the second principal component (Factor 2) was positively correlated with the physicochemical parameters T°, NO2−, NO3−, and K+ and negatively correlated with the bacteriological parameters FC, TC, and FS. These ions are mostly of anthropogenic origin and their presence in groundwater is either due to the discharge of wastewater or the leaching of fertilizers. While the third principal component (Factor 3) was positively correlated with PI, NH4+, NO3−, HCO3−, Ca2+, PI, and SO42−. But, Cond negatively correlated with physicochemical parameters which are T° and pH (Figure 6). The presence of these ions is attributed to the degradation of organic matter by microorganisms in the superficial soil formations, with the production of CO2 to be carried to depth by groundwater. However, the fourth principal component (Factor 4) was positively correlated with NH4+, NO3−, pH, HCO3−, TC, FC, FS, K+, Na+, and PI, and negatively correlated with T°. These ions are mainly of anthropogenic origin and their presence in groundwater is explained by the leaching of applied fertilizers and by contamination by faecal pollution germs.


## 3.4. Hierarchical Ascending Classification

Hierarchical ascending classification (HAC) aims to classify individuals by matching them to the least dissimilarity, for a set of variables. The result of HAC is presented in the form of dendrograms [15]. The closest individuals are grouped based on a dendrogram and linked by an “aggregation criterion.” They constitute a type. The dendrogram connects subjects by least dissimilarity, and only the direction of the variables can reveal the unifying character of the types. The CAH used here is that of Ward’s method. It has the particularity of recalculating the aggregation indices for each stage of the classification [15].Figure7 shows the hierarchical tree constructed with the rescaled class combination distance and the Ward criterion for nineteen sample points distributed over the entire area. Indeed, if the cut-off level is at distance 5, two classes can be distinguished. The first class includes the closest points 1, 2, 4.5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 18, and 19 which are homogeneous with points 3. This class is characterised by high contents of physicochemical parameters, in particular Cond, Na+, Ca2+, Mg2+, Cl−, NO2−, NO3−, HCO3−, and SO42−, which reach, respectively, up to 10355 µS/cm, 1226, 5 mg/l, 601 mg/l, 693 mg/l, 3597 mg/l, 176 mg/l, 134 mg/l, 811, 3 mg/l, and 1395 mg/l. On the other hand, the second class includes points 12 and 17 which have high levels of TC (36000/100 ml), FC (4800/100 ml), and FS (9000/100 ml).Figure 7
Dendrogram of nineteen Angads groundwater sample points.The results of the hierarchical tree constructed with the combined distance of the resized classes and the Ward criterion of nineteen physicochemical and bacteriological parameters (Figure8) reveal that from the distance cut-off level 5, three classes can be distinguished. The first class includes physicochemical parameters such as NH4+, Mn2+, PI, Fe2+, pH, K+, T°, NO2−, NO3−, Mg2+, Ca2+, Na+, SO42−, HCO3−, and Cl− which are the closest and are homogeneous with Cond, this class realizes that the mineralization of groundwater is controlled by the nature of the geological formations present in the area. The other two classes include bacteriological parameters, namely FC and FS in the second class, and TC in the third class, indicating that the second class groundwater is contaminated by faecal matter, while the third class indicates that the groundwater may be contaminated by more harmful microorganisms.Figure 8
Dendrogram of nineteen physicochemical and bacteriological parameters of the Angads groundwater.


## 3.5. Hydrogeochemical Analysis

The results of the hydrogeochemical analysis using the Piper diagram (Figure9) show that the chemical parameters (cation and major anion) of the groundwater from nineteen sampling points in the Angads aquifer were processed using the Piper diagram. This diagram shows the hydrogeochemical facies. The results of which show two types of facies: one chloride and sulphate calcic and magnesian at sampling points 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, and 19, occupying 89.47%, and the other is chloride sodium and potassium facies at both points 7 and 10 with a percentage of 10.52%.Figure 9
Piper diagram of Angads groundwater in September 2020.The results of the Schoeller–Berkaloff diagram analysis (Figures10(a) and 10(b)) of nineteen sampling points, of the Angads groundwater, reveal that these waters show identical profiles in the majority of the sampling points. Except for the four points 7, 8, 10 (Figure 10(a)), and 15 (Figure 10(b)) which show high values of some chemical elements, namely, point 7 in Na+, K+, Cl−, HCO3−, and CO3−, for point 8 in Mg2+ and Cl−, for point 10 in Na+, K+, and Cl− and for point 15 in Mg2+, Na+, K+, and Cl−.Figure 10
(a, b) Schoeller–Berkaloff diagram of Angads groundwater in September 2020.
(a)(b)


## 3.6. Assessment of Water Quality for Human Consumption and Irrigation

To determine whether the groundwater from nineteen sampling points in the Angads aquifer is intended for human consumption and irrigation, hydrogeochemical and bacteriological parameters were compared with Moroccan and World Health Organization standards (Table3). The results reveal that the parameters NO3−, Cond, Cl−, Fe2+, Mn2+, and HCO3− exceed Moroccan and WHO standards for human food and irrigation, with the highest values recorded in wells located downstream of the wastewater treatment plant and the other near the dump. In these wells, these parameters reach up to NO3− (134 mg/l), Cond (10355 µS/cm), Cl− (3597 mg/l), Fe2+ (17.7 mg/l), Mn2+ (0.466 mg/l), HCO3− (811 mg/l), instead of NO3− (50 mg/l), Cond (2700 µs/cm), Cl− (750 mg/l), Fe2+ (5 mg/l), Mn2+ (0.2 mg/l), and HCO3− (518 mg/l).Table 3
The Moroccan food and irrigation standards and the WHO guidance values 2011.
Physicochemical and bacteriological parametersUnit of measurementWHO guide values 2011Moroccan standards for human foodWater quality standards for irrigationT°°CAcceptable35pH6.5–8.56.5 < pH < 8.56.5 à 8.4CondµS cm−1400270012NH4+mg.L−11.50.5—Na+mg.L−1200——K+mg.L−112——Ca2+mg.L−1ND——Mg2+mg.L−1ND——Fe2+mg.L−10.30.3—Mn2+mg.L−10.50.50.2Cl−mg.L−1250750—NO2−mg.L−130.5—NO3−mg.L−15050—HCO3−mg.L−1ND—518SO42−mg.L−1250400250TCufc/100 ml)>1/100 ml0/100 ml—FCufc/100 ml—0/100 ml1000/100 mlFSufc/100 ml>1/100 ml——PImg.L−1———The comparison of the FC, TC, and FS values of these groundwater with the Moroccan standards for human food and irrigation as well as the World Health Organization. The highest values were recorded in wells located downstream of the wastewater treatment plant and others near and downstream of the Oujda public dump, reaching up to FC (36000/100 ml), TC (4800/100 ml), and FS (9000/100 ml).


## 4. Discussion

The importance given to the mineralogical nature of groundwater as well as the validity of these waters for human consumption and irrigation are the subject of physicochemical and bacteriological studies to preserve these vital resources. Our results concerning the Angads groundwater revealed that the physical parameters (Cond) and the chemical parameters NO3−, Cl−, Fe2+, Mn2+, and HCO3−, exceeded the norms for water consumption and irrigation. As well as the presence of pathogenic germs which are FC, TC, and FS, which make these waters unfit for human consumption and irrigation. At the national level, these results are similar to previous studies, especially the study that was done in the city of Oujda shows an increase in the content of physical elements (Cond), and chemical elements Cl−, NO3−, and NO2−, which exceed the standards for drinking water [16]. Similarly, the study in the plain of Angads in Eastern Morocco by Es-sousy, shows that the groundwater located downstream of the treatment plant has a high content of NO3−, which is higher than 50 mg/l [12].The results of the bacteriological study of the groundwater studied revealed the presence of significant faecal contamination by the presence of FC, TC, and FS. This means that these waters are unfit for human consumption and their use for watering green spaces and irrigating agricultural land could constitute risks to the health of the population. On the other hand, this contamination could be explained by the presence of the wastewater treatment plant in the study area. In this context, studies have shown that groundwater around the WWTP generally shows increased bacterial contamination [17]. Indeed, Agarwal’s 2019 study found that 95.4% of groundwater samples and 92.3% of leachate samples have high nitrate concentrations and are therefore not drinkable [18]. Similarly, the study by [19] in China proved that about 40% of groundwater samples were undrinkable due to high sulphide, fluoride, and chloride contents [19].Concerning the physicochemical and bacteriological study by the multivariate statistical method using principal component analysis revealed a positive correlation matrix between the parameters Na+∗ Cond, Ca2+∗ Cond, Mg2+∗ Cond, Cl−∗ Cond, Mg2+∗ Na+, Cl−∗ Na+, Mg2+∗ Ca2+, Cl−∗ Ca2+, Cl−∗ Mg2+, SO42−∗ Cond, SO42−∗ Na+, SO42−∗ Ca2+, SO42−∗ Mg2+, SO42−∗ Cl−, FS∗, and FC. Generally, the factorial designs (F1-F2), (F1–F3), and (F1–F4), show a negative correlation with the parameters Fe2+, TC and K+. This could be due to the heterogeneity of the waters of these aquifers and the low values of these ions recorded, as according to the work of Souley Moussa et al. in 2019 [9], out of the nineteen parameters he studied, five of them do not participate in the constitution of the factorial axes. Similarly, the distribution of physicochemical and bacteriological parameters on the factorial planes (F1-F2), (F1–F3), and (F1–F4) allowed the identification of the phenomena at the origin of the mineralization of these groundwater, which are related to soil rainfall and residence time in the aquifer, as well as to agricultural pollution due to the use of nitrogenous fertilizers, and to water-rock contact. These results are similar to those found in the study by Bouteraa and colleagues who showed that groundwater quality is influenced by geochemical processes (water-rock interaction) and human practices (irrigation) [20]. In addition, the study conducted in the Zinder region of Niger revealed that there are two mechanisms responsible for water mineralization which are soil rainfall and residence time in the aquifer [9].On the other hand, the distribution of nineteen physicochemical and bacteriological parameters using varimax rotation on the factorial planes (Factor 1-Factor 2), (Factor 1–Factor 3), and (Factor 1–Factor 4) showed that all factors except Factor 1 showed contamination by nitrates which are mainly due to anthropogenic action and are introduced into the subsoil, either by leaching of applied fertilizers or by wastewater discharge. Similar studies have affirmed these results on the origin of nitrates in groundwater, including the study of water from three aquifers in the Tillabery region [21]. In addition, the results of analysis by ascending hierarchical classification on the different sampling points studied of the Angads aquifer showed the existence of two well-distinguished classes. The first class includes the majority (89.5%) of these points, namely, points 1, 2, 3, 4.5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 18, and 19, and the second includes only 10.5%, which represents the two points 12 and 17.In the same sense, the in-depth analysis by the ascending hierarchical classification of all the physicochemical and bacteriological parameters studied allowed us to identify three classes. The first one includes the sixteen physicochemical parameters namely NH4+, Mn2+, PI, Fe2+, pH, K, T°, NO2−, NO3−, Mg2+, Ca2+, Na+, SO42−, HCO3−, Cl−, and Cond, which shows that the mineralization of groundwater is controlled by the nature of the geological formations present in the region, whereas the second class includes only faecal bacteriological parameters such as FC and FS, which translates into faecal contamination. Thus, the third class includes TC, the presence of which indicates that the groundwater may be contaminated with more harmful microorganisms. These results were confirmed by previous studies which revealed that the bottom-up hierarchical classification indicates that groundwater mineralization is controlled by the nature of the geological formations that exist in the region [21].Concerning the evaluation of groundwater quality for possible use in human food and irrigation, our analysis shows that physicochemical parameters such as Cond, NO3−, Cl−, Fe2+, Mn2+, and HCO3−, as well as bacteriological parameters FC, TC, and FS exceed the standards of the World Health Organization and the Moroccan standards for human food and irrigation [22–24]. Therefore, it can be said that these waters are unsuitable for human consumption and irrigation. These results are similar to those found in the study that was done in the city of Oujda by El-Kharmouz, which shows an increase in the content of chemical elements Cl−, nitrite ions NO2− and NO3−, and physical elements (Cond), which exceed the standards for drinking water [16]. Similarly for the study in the plain of Angads in Eastern Morocco by Es-sousy in 2018 shows that the groundwater has a high content of NO3− which is higher than 50 mg/l which exceeds the standards for drinking water [12].In our study, the highest contamination values were recorded in the wells located downstream of the wastewater treatment plant and the other near the landfill. This means that the presence of landfills and WWTPs in the vicinity of inhabitants increases the level of groundwater contamination and also presents an increased risk to health and the environment [17]. Indeed, landfills should be located away from houses, as their existence also provides food for stray dogs and an environment for the proliferation of disease-carrying insects that threaten human and animal health [25, 26].Thus, the physicochemical and bacteriological analyses of the groundwater from nineteen sampling points distributed over the Angads aquifer using the Piper diagram revealed the existence of chloride and sulphate calcic and magnesian facies with a percentage of 89.47%. This shows the infiltration and dissolution of the Triassic clay-evaporite rocks and generally represents mineralized waters. These results have been confirmed by previous studies, such as the study by Chaoui and Amrani [27, 28].While the use of the Schöeller–Berkaloff diagram showed that the majority of the sampling points have the same shapes except for the four points 7, 8, 10, and 15. These points have high values in some chemical parameters, namely, point 7 in Na+, K+, Cl−, HCO3−, and CO3−, point 8 in Mg2+, Cl−, and SO42− for point 10 in Na+, K+, and Cl− and for point 15 in Mg2+, Na+, K+, Cl−, and SO42−. This explains why the groundwater of the Angads aquifer shows high mineralization. These results have been confirmed by previous studies such as the study by Amrani in 2014 [27].


## 5. Conclusion

The present study presents for the first time the physicochemical and bacteriological parameters of the groundwater of the Angads aquifer located in eastern Morocco. The hydrogeochemical study, which was based on three multivariate methods: principal component analysis, varimax rotation of factors, and hierarchical ascending classification showed that these waters present a contamination by nitrates due to the high values of NO3−, and an important mineralization due to the presence of Cond, HCO3−, Ca2+, Mg2+, and SO42− ions. Indeed, the study of facies using Piper and Schoeller–Berkaloff diagrams revealed that these waters are highly mineralized as the dominant facies was chloride and the sulphate facies calcium and magnesium with a percentage of 89.47%. In addition, the bacteriological study revealed contamination of faecal origin with high values of total and faecal coliforms, as well as faecal streptococci. Our study concluded that these waters are unfit for human consumption and irrigation. These results are very important to know the current status of these water resources. Sustainable groundwater management plans in the region need to be implemented with a focus on reducing pesticide use, controlling fertilizer use and water purification.



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*Source: 2806854-2023-01-17.xml*