3.1. Geochemical composition of groundwater
Table 1 shows the geochemistry of groundwater variables of samples (n = 243) collected from the study area. The pH value in groundwater samples were varied from 7.6–8.3 with an average value of 7.86 and was found in WHO recommended values indicates slightly alkaline nature of groundwater sources. Being as key water quality parameter pH determination is compulsory due to its vital role in water chemistry, alkalinity, solubility of groundwater variables . The value of total dissolved solids (TDS) were recorded ranging from 209–3116 mg/L with mean value of 500 mg/L and were found in acceptable limit of WHO. The elevated value of TDS in groundwater sources is due to ion dissolution, which might be credited to progressively depleting salts and minerals over time . The electrical conductivity (EC) value in groundwater samples were ranged from 249–865µs/cm having an average value of 511.23 µs/cm. The high (EC) water samples indicate aquifer constituent leakage or suspension, as well as other sources such as saline water bodies. As concentration in groundwater samples varied from 1.04–92.30 µg/L with an average value of 39.49µg/L, 91% samples were recorded beyond the recommended value of 10µg/L recommended by WHO. The presence of high arsenic in drinking groundwater is a direct result of anthropogenic and geogenic sources, and it has been identified as a severe environmental concern. As can also be released into groundwater due to high salinity, alkalinity, and anoxic conditions . Geogenic As pollution of groundwater is more widespread in alluvial aquifers. Gravel, sandstone, silt, and sand that have been in a river canal or food plain for a long time make up these aquifers . In comparison to other areas of Punjab, Pakistan, the study area has a high concentration of arsenic, which could have negative health consequences for its residents. The concentration of Mn in groundwater samples ranging from 0.01–0.90 mg/L with an average value of 0.19 mg/L, 15% samples were beyond the permitted limit recommended by WHO. Mn is a naturally occurring mineral that is one of the most numerous metals on the planet's surface, in air, water, and soil. It can be found in natural sources of groundwater and surface water, as well as human activity such as mining and industrial wastes . Mn is also utilized in a variety of sectors, including iron and steel alloys, batteries, glass, fireworks, cleaning supplies, fertilizers, varnish, fungicides, cosmetics, and livestock feed additions . The Pb concentration in groundwater samples were in the range of 0.01–0.40 mg/L having an average value of 0.05 mg/L. Among (n = 243) groundwater samples 97% samples were beyond the permitted limit of WHO. Lead (Pb) can be found at varied degrees of solubility in rocks and mineral deposits. The elevated (Pb) concentrations in groundwater can result from the leaching of such rocks and minerals . The concentration of Zn in groundwater samples ranges from 0.01-4 mg/L having a mean value of 1.07 mg/L, 15% samples were beyond the recommended value of WHO. The majority of zinc is introduced into water by artificial channels, such as by-products of steel manufacture or coal-fired power plants, or waste material combustion. Some fertilizers include zinc, which can seep into groundwater . The concentration of Cu varied from 0.01–1.9 mg/L with an average value of 0.41 mg/L and all of the sample were in acceptable guidelines of WHO. The factors which may lead the elevated concentration of Cu in groundwater sources are corrosion of residential plumbing, faucets, and water fixtures. Copper leaches from plumbing materials including pipes, fittings, and brass faucets and is absorbed by water . The concentration of Ni in groundwater samples were recorded ranges from 0.01–0.7 with an average value of 0.03 mg/L, and all of the samples were in WHO recommended guideline value. The prime cause of Ni in groundwater is leaching from metals in contact with drinking-water, such as pipes and fittings. Nickel, on the other hand, may be present in some groundwater sources due to dissolution from nickel ore-bearing rocks . The Fe concentration in groundwater samples was detected ranges from 0.04–0.70 mg/L with an average value of 0.26 mg/L, among (n = 243) 45% samples were beyond the permitted limit recommended by WHO. Iron is the second most abundant metallic element in the earth's crust, while it has a low concentration in water. Whenever rainwater seeps, percolates, and flows down the soil and rocks, dissolved iron from the soil and rock formations dissolves in the groundwater . The results of this research were compared with the study of  conducted in Vehari, Punjab, Pakistan and the comparison shows similarity with the above-mentioned research work.
3.2. Principal component analysis
To explore the association between groundwater variables, a principal component analysis (PCA) approach was employed to evaluate all of the geochemical processes occurring in the research area.
A total of five principal components were achieved for (n = 243) samples, such as PC1, PC2, PC3, PC4, and PC5, respectively with eigenvalues of 1.483, 1.321, 1.186, 1.028, and 0.998 respectively. A variability for each factor were calculated to be 14.826%, 13.207%, 11.86%, 10.285%, and 9.977% respectively with total variance of 60.54%.
PC1 was counted with 14.826% variability having an eigenvalue of 1.483 and shows strong and moderate loading for pH, TDS, EC, and Fe and their numerical values were calculated to be 0.723, 0.564, 0.577, respectively. PC1 suggested that geogenic input has a significant impact on groundwater physicochemical variables, and that pH and TDS play an important role in the saturation of water variables in this study . PC2 was calculated with variability of 13.207% having an eigenvalue 1.321 which shows strong loading for Mn and Ni, their numerical values are 0.608, and 0.645 respectively. Manganese (Mn) is an element that can be found naturally in rocks and soil, as well as in subsurface pollution sources. Manganese is rarely found in a water source on its own. It's common in iron-bearing streams, but it's less common than iron. The primary source of nickel (Ni) are ore-bearing rocks, which can contribute pollution of Ni in groundwater sources . PC2 also reflect for geogenic source of contamination in groundwater. PC3 was counted with variability of 11.86% with eigenvalue of 1.186 and shows strong negative loading for As and Pb having a loading value of -0.683 and − 0.515 respectively. The negative values of these two variables shows that they have no direct effect on each other. Arsenic (As) can enter groundwater and drinking water from a variety of natural sources as well as manmade acts. Geologic formations (e.g., sedimentary deposits/rocks, volcanic rocks and soils), geothermal activity, coal, and volcanic activities are all key natural sources. Anthropogenic activities such as mining, burning of fossil fuels, use of arsenical fungicides, herbicides, and insecticides in agriculture, and the use of wood preservatives are the main anthropogenic sources of As pollution of groundwater. Coal combustion has a significant impact on As pollution in the environment . The origin of Pb in shallow groundwater systems may contain naturally occurring ores rich in various pollutants, which seep into waterbodies and pollute them. Groundwater contamination with high Pb levels has been related to these ores. Moreover, mining and smelting of ore, manufacturing of lead-containing products, coal and oil burning, and waste incineration are all anthropogenic sources of lead . PC3 shows mixed type of contaminant which may contaminate groundwater sources. PC4 shows variability of 10.285% with eigenvalue 1.028 and shows strong loading for TDS and Pb with values of 0.511 and 0.640 respectively. Natural sources, sewage, urban and agricultural run-off, and industries of lead manufacturing products, wastewater all contribute to TDS and Pb in water systems. Salts used for de-icing roads can potentially contribute to TDS levels in water supplies . PC4 shows mixed type of source that the aquifers of the study area are contaminated due to geogenic and anthropogenic actions. PC5 was counted with variability of 9.997% with eigenvalue 0.998 which shows strong negative loading for EC and positive for Cu and their values are − 0.522, 0.555, respectively, suggesting that these two variables had not direct effect on each other. The high electrical conductivity (EC) in groundwater sources is due conductive ions come from dissolved salts, and inorganic substances such as sulfides, chloride, and carbonate compounds, while copper (Cu) levels in surface and groundwater are typically relatively low. Copper contamination can occur in the environment as a result of mining, farming, manufacturing, and municipal or industrial effluent . PC5 reflect for mixed type due to geogenic and anthropogenic source of contamination. As shown in Fig. 2 principal component analysis (PCA) results with total variability of (60.154%) reveal that the groundwater sources of the study area are contaminated due to (30.9%) geogenic sources, (31.3%) anthropogenic sources, and (37.6%) of mixed type including both geogenic and anthropogenic source of contamination.
3.3. Mineral phases of PHMs in groundwater
Saturation data is being used to estimate subsurface minerals. As shown in Fig. 3 the results of mineral phases for groundwater samples, such minerals include, hausmannite, zinc hydroxide, pyrochroite, lead hydroxide, goethite, pyrolusite, respectively. The Si value for hausmannite, zinc hydroxide, and pyrochroite were found in the range of (-7.6941 − 3.5589), (-1.3947 − 2.3741), and (-5.1547−-1.8704), and their mean values were recorded to be (-2.856880), (0.713146), and (-3.718981), respectively. The SI value for lead hydroxide, pyrolusite, and goethite, were found in the range of (1.7007 − 3.8798), (-8.1348−-3.4504), and (9.2632–10.1506), and their mean values were recorded to be (2.446345), (-6.168955), and (9.3142), respectively. The saturation indices result of mineral phases shows that the groundwater sources of the study area were saturated for goethite, lead hydroxide, and zinc hydroxide minerals, which indicates that these minerals had a significant role in the contamination of groundwater sources of the study area.
3.4 Quantile-Quantile (Q-Q) plotting
To obtain the outcome of Q-Q plotting, groundwater data for selected elemental composition were plotted in SPSS program. It's a graphical method for showing data from the first data set quantiles against the second data set. The expected normal values were shown in the first data set, whereas the observed values were shown in the second data set. At a 45° reference line, both values are sorted up and down in the form of scatter plot. The standard distribution outline is revealed by the values of quantiles, which can be found in a straight diagonal line. Figure 4 shows the Q-Q plotting result for selected groundwater variables. The quantiles R2 values for As, Mn, Zn, Cu, Ni, and Fe in the normal Q-Q box plots were found to be (0.971), (1), (0.989), (0.991), (1), and (1), respectively.
3.5. Human health risk exposure assessment
For the purpose of estimating risk exposure in the research region, a human health risk exposure survey was done. In the study area, the research team visited several groups of people, including youngsters (1–16 years old) and adults (17–55 years old). The majority of the population, or 70% of local respondents, believe that the study area's industrial and commercial activities are to blame for the contamination of the groundwater and the study area's health situation. In the study area the common reported disorders were, irritability, constipation, sleep disorders, hearing loss, exhaustion, cramps, gastrointestinal disease, neurological damage, learning difficulties, low appetite, stunted growth, organ failure, flu, vomiting, coma, and convulsions were among the most prevalent diseases. The effects of PHMs in groundwater were examined in terms of chronic daily intake (CDI), Hazard Quotient (HQ), and Cancer Risk (CR), to better comprehend the exact environmental guidelines and increased health frustrates for the local people. In this investigation, CDI, HQ, and CR via oral ingestion route for two groups of populations, children and adults, were computed following USEPA criteria, and the findings are shown in Table 4. As a result of groundwater consumption, the majority of persons in the research region were highly exposed to PHMs.
As shown in Table 3 the average CDI value of As, Mn, Pb, Zn, Cu, Ni, and Fe, for children were calculated to be 4.73E-04, 2.35E-06, 5.76E-07, 1.29E-05, 4.96E-06, 3.59E-07, and 3.10E-06 respectively. Similarly, the average CDI value of As, Mn, Pb, Zn, Cu, Ni, and Fe, for adults were counted to be 6.01E-05, 2.98E-07, 7.31E-08, 1.63E-06, 6.3E-07, 4.55E-08, and 3.94E-07 respectively. The average non-carcinogenic risk of As, Mn, Pb, Zn, Cu, and Ni, for children were calculated to be 1.58E + 00, 1.68E-05, 3.61E-14, 4.28E-08, 1.34E-04, and 1.79E-05 respectively. Likewise, the non-carcinogenic value of the abovementioned PHMs for adults were calculated and their values are 2.00E-01, 2.13E-06, 2.09E-05, 5.44E-09, 1.70E-05, and 2.28E-06, respectively. The average carcinogenic-risk of As, Pb, and Ni for children were calculated and their values were found to be 3.16E-04, 1.48E-14, and 2.11E-07, respectively. Similarly, the average carcinogenic risk of As, Pb, and Ni, for adults were found to be 4.01E-05, 8.61E-06, and 2.68E-08, respectively as shown in Table 4, thus it was noticed from the result that PHMs in groundwater sources of the study area has an adverse effect on the population of the study area. The result of this study was compared with the study conducted by  and , the comparison showed that the results of this research was similar to the above mentioned research work.