Evaluation of Heavy Metals in Soil Wastewater Stream

Environmental pollution is one of the main factors that significantly affect biological systems and human health. Soil pollution with heavy metals is an increasingly pressing problem worldwide. In general, heavy metals are stable and do not decompose, unlike other organic pollutants. The quantity of them is natural components of soil crust, the remaining come from human activities, which may result from the extensive use of sewage. In the present study, a methodology aimed at simultaneous quantification of 16 heavy elements in soil of 3 different regions was developed. The concentration of 16 soil heavy metals (Se, Cd, V, Be, As, Mn, Co, Zn, Fe, Cr, Pb, Ni, Cu, Mo, Hg, and Ti) was measured in 11 sampling along Riyadh, Qassim, and Medina, Kingdom of Saudi Arabia from 3 sites soil treated with sewage water. These chemical minerals were identified in the samples using an ICPE-9000 spectrometer. The assessment of heavy metal contamination was derived using enrichment factors (EF), the pollution load index (PLI), and geoaccumulation index (Igeo). This study revealed that the soil is predominantly polluted by Cd, As, and Mo of Riyadh and Medina and As, Mo, and Cd of Qassim region at site B and site C, respectively. As recorded, the highest concentration value of 5000 mg/kg for Fe at site (B) followed by Cu. The Igeo value of Cd is 1.1520 in Medina region. The Igeo value of Se is 3.2395 in Medina region, while its cumulative geographical index decreased in the regions of Riyadh and Qassim, which amounted to 2.6114 and 2.1699, respectively. The Igeo values of the rest of the minerals in the three regions studied indicated that the soil is unpolluted, while it was slightly to moderately polluted for both Mo and Hg in most regions studied. The minerals in the soil at all sites studied were less than the general average concentration. With the exception of mercury, molybdenum, arsenic, cadmium, and selenium, whose concentration exceeded the permissible and recommended limits. The increasing order of concentration of minerals was Be < V < Cd < Hg < Mo < Co < Zn < Pb < Cr < Se < As < Ni < Ti < Mn < Cu < Fe at all sites, respectively.


Introduction
Heavy metal toxicity is related with its accumulation in the soil. is leads to soil pollution. Soil pollution with heavy metals is an increasingly pressing problem worldwide, which may result from the extensive use of sewage for irrigation [1]. In general, heavy metals are stable and do not decompose unlike other organic pollutants [2]. Heavy elements are natural components of soil crust. However, human activities radically changed their geochemical and biochemical balance [3]. e increase of using toxic chemical compounds by people leads to an increase in the volume of wastewater [4]. Sewage water irrigation can contribute to the heavy metal amount in soil [5]. e food made from plants grown in sewage water is highly contaminated [6]. Wastewater contaminated with trace minerals, such as lead (Pb), zinc (Zn), copper (Cu), arsenic (As), chromium (Cr), molybdenum (Mo), boron (B), cobalt (Co), and manganese (Mn), many of them are unnecessary, but their buildup makes them toxic to plants, animals, and humans [7]. Using waste wastewater for a long time leads to an increase in the concentration of heavy metals in the soil [8,9]. Soil consists of organic compounds and heterogeneous components of fluids and minerals that compose it [10]. e elements that man creates and leaves in the soil are greater than the elements from natural sources [11,12].
Polluted water affects the soil. is effect is not only in industrial areas, but included even in agricultural fields, such as riverbeds [13][14][15][16]. Soil pollution and its toxicity are associated with high levels of heavy metals [17]. Concentrations of trace metals in sewage effluents vary from one city to another [18]. Despite the fact that the concentration of heavy metals in sewage effluents is low, the use of these wastewaters on agricultural lands for a long time results in the increase of levels of these metals in soils [18]. Contamination of toxic trace elements (TES) in agricultural soils is due to human activities [19]. Arsenic (As), lead (Pb), mercury (Hg), and cadmium (Cd), which are toxic, lead to some acute and chronic conditions [20]. Heavy metals are extremely hazardous to health as their accumulation in human and animal organisms causes severe hazards [21][22][23][24].
Remediation of these contaminated soils is due to human health and safe food production. Toxic metals minimized soil quality and affect plant productivity [25]. e presence of heavy metals in the soil leads to a significant change in its properties, which results in physiological, chemical, and biological changes in plants, which leads to reduced growth and thus reduces crop yield [26]. Irrigation with sewage water for a long time leads to changes in the soil due to the deposition of toxic elements [27]. ere are a large number of reports [28,29] showing the use of sewage water for irrigation is a major concern for the presence of toxic elements. Permanent irrigation with sewage water for agricultural lands led to food contamination [30].
Although wastewater contains small percentages of heavy elements (manganese, lead, iron, cadmium, and chromium), soil showed higher percentages due to the accumulation. Mineral accumulation in wastewater-irrigated soils in the following order: Fe > Mn > Pb > Cr > Cd [31]. e bioactivity of Cu, Zn, Ni, Cd, and Pd is significantly reduced in soils with a pH above 7 [32]. e industrialization of modern societies has created an exponential increase in the waste produced per person. In Saudi Arabia in 2016, solid waste are more than 6 million tons per year of solid waste in Riyadh, Jeddah, and Dammam [33]. UNESCO recognizes Jeddah as a historical city as a World Heritage Site [34,35]. Environmental pollution is one of the obstacles when it comes to the revitalization and development of the city. Since 1962, Jeddah has been expanding rapidly. e largest pollution source is the sewage lake in Jeddah (east of Jeddah) since it contains toxic compounds due to water sedimentation in the residential area [36]. e objective of this work is to determine the soil contamination level of 16 heavy elements and compare them with the soil around the sewage plants and streams of Riyadh, Qassim, and Medina areas in the Kingdom of Saudi Arabia. ese minerals were analyzed using the ICPE-9000 device.

Soil Materials.
A total of 11 topsoil samples were collected from 3 different regions around the treated wastewater basin; region A represents the area on the wastewater basin; region B just 50 meters from the water basin of sewage plant; and region C just 100 meters from the sewage basin of Riyadh, Qassim, and Medina in Kingdom of Saudi Arabia. e soil was dried and sieved with a 2 mm sieve and left for a week at room temperature then placed in airtight plastic bags for preservation.

Methods.
Various methods were applied to detect and evaluate heavy metals in the soil. Atomic Absorption (flame), Atomic Absorption (furnace), and Inductively Coupled Plasma (ICP) techniques were developed over the years for this purpose. Among the above methods, ICP is the more convenient method for qualitative and quantitative analysis.
at is why this study had been designed to develop a high sensitivity, lower running cost, and the larger number of measured elements the more apparent time efficiency.

ICP Spectrometry Parameters.
Quantitative analysis was performed on a Shimadzu ICPE-9000 Spectrometer equipped with a highly efficient ionization and emission sources and CCD (charge-coupled device) detector. Its temperature was set at −14.89°C. Spectrum resolution, to avoid spectral interference was achieved automatically. A high-purity argon carrier gas was used. e flow rate of plasma gas (Ar) was maintained at 10 L/min, auxiliary gas (Ar) at 0.6 L/min, and carrier gas (Ar) at 0.7 L/min. e direction position AXIAL view, Rf power at 1.2 kW, pressure at 450 + 10 kPa. e rotation speed was adjusted to 20 rpm.

Preparation of Working Solution Standards.
Working standard solutions were prepared by diluting a Scharlau ICP multi-element calibration standard solution in 5% HNO 3 using deionized water to 1000 ml/L.

Preparation of Samples.
To prepare soil samples wet digestion technique was performed by using concentrated acids. About 0.5 g of soil sample was taken into a clean and dry beaker. About 3 ml of conc. nitric acid and 1 ml of conc. hydrochloric acid were added to it. e resulting mixture was stored for 24 h. e mixture was placed in a heater at 150°C for 2 h. After cooling to room temperature, the mixture was filtered into a 500 ml volumetric flask, its volume adjusted up to the mark with deionized water.  International Journal of Analytical Chemistry

Statistical Analyses.
To find out the significance and significant differences of soil sample data, statistical analysis was performed by means of a test ANOVA.

Contamination Assessment Methods.
To assess soil enrichment and pollution caused by minerals, Pollution Load Index (PLI) enrichment factors (EF) in addition to the geoaccumulation index (I geo ) were used.
(1) Assessment of Heavy Metal Pollution. To assess the contamination degree and pollution of the proposed method, concentration levels of samples [37] were determined using (PLI) pollution load index. e pollution load index is measured by comparing the concentration value of the sample to the value of the mineral background in the soil.
e PLI was determined [37] as follows: where PLI is the contamination level; P i is the stand for single element contamination index i; and n is the number of elements.
where P i is the stand for single element contamination index i; C i is the concentration of the element in the sample; and S i is the posterior focus of the sample. e value PLI > 1 indicates a contaminated site; the value of PLI < 1 indicates a contaminated site in the absence of pollution.

Quantitative Measurement of Mineral Pollution.
To measure the extent of metal contamination by the proposed method, geoaccumulation Index (I geo ) was determined by comparing the concentration of the metal sample in the soil with the geographical accumulation parameter. I geo has been calculated [38] as follows: where C n is the measured total concentration of the element n in the soil; B n is the average concentration of element n geochemical background parameter; and 1.5 is the constant used to reduce the effects of potential changes in soil background values.I geo ≤ 0 indicates unpolluted; 0 < I geo < 1 indicating unpolluted/moderately polluted; 1 < I geo < 2 moderately polluted; 2 < I geo < 3 indicating moderately/ strongly polluted; 3 <I geo < 5 indicating strongly polluted; 4 < I geo < 5 indicating strongly/extremely polluted; and I geo > 5 indicating extremely polluted [38].

Assessment of Soil Enrichment.
To assess the presence and intensity of anthropogenic contaminant deposition on surface soil enrichment factor (EF) as an indicator was calculated by normalization of iron [39][40][41][42] concentration in the topsoil with respect to the concentration of a reference element. EF is calculated [43] as follows: where EF is the enrichment factor; C x is the concentration of the element of interest; and C Fe is the concentration of a reference element (Fe) for the purpose of normalization. EF < 2 represents a minimal deficiency of the element, moderate: 2 < EF < 5, significant: 5 < EF < 20, strong: 20 < EF < 40, and extremely high enrichment: EF < 40.

Physical and Chemical Properties of the Soil Sample.
e pH and electrical conductivity values of soil as shown in Table 1 are ranged between 5.8 to 7 and 1.02 to 41.2 μs/cm, 6.4 to 7.3 and 6.7 to 2.51 μs/cm, and 6.8 to 7.5 and 0.39 to 2.6 μs/cm at stream site A (represents the position at the edge of the sewage stream), B (represents the right of the edge (outside the sewage stream) at a distance of 50 m), and C (at the right of the edge (outside the sewage stream) at a distance of 100 m), respectively. pH values are within the allowable limit [44,45], except at site A of Qassim region (5.8). On variation with distance away from sewage stream, the highest soil pH level with continuous irrigation with sewage water can cause an increase in sulfate levels in wastewater [46,47]. e electrical conductivity of soil contaminated with sewage water in most of the samples exceeded the value of 1 μs/cm, which indicates that this soil is salty in nature. e total dissolved solids (TDS) values at three sites as shown in Table 1 varied greatly. e highest (TDS) values are 7165 and 11845 mg/L observed at site A of Qassim and Medina, respectively, while that far from sites B and C are significantly decreased. e highest Cl − anion concentration (1189.9 mg/L) was observed at sewage stream of Qassim region. Generally decreasing soil pH was observed, it could be due to higher inputs of organic matter as the result of sewage irrigation [48]. e results shown in Table 1 indicate that the mobility of heavy metals decreases with increasing soil pH it could be due to the precipitation of hydroxides or carbonates from insoluble organic complexes.

Analysis of Heavy Metals of Soil Samples. (1) Metals at
Sewage Soil of Riyadh. e concentration of Cd, V, Be, Co, Zn, Cr, Pb, Mo, and Hg in the soil shown in Table 2 ranges from 0.1 to 2.05 mg/kg at Riyadh regions around the sewage site (A, B, and C), which indicate that its concentrations are lower than other minerals. While the concentration of Se, As, Mn, Ni, and Ti increased, are ranged between 3.4 and 5.5 mg/kg. e concentration of Cu is 10 mg/kg, which indicates a high concentration, while the concentration of Fe is 445 mg/kg at this site, which indicates the highest mineral concentration. e concentration of all minerals in the soil is less than the global average concentration at sewage stream site A, while that of Se, Cd, and Hg are 18, 4, and 13 times higher, respectively. e results are shown that there was a International Journal of Analytical Chemistry discrepancy in the concentration of minerals in the soil at a distance of 50 m away from the sewage stream (region B).
In general, the increasing order of concentrations of minerals was Fe > As > Cu > Mn > Se > Ti > Ni > Zn > Co > Mo > Pb > Cr > Hg > Cd > V > Be and within the permissible limit in the soil except that of Se, Cd, As, Mo, and Hg. eir proportions in the soil were higher than the soil recommended limit of 100 m from the sewage stream site C. e concentration of Fe is 750 mg/kg at site C, which indicates a high concentration, followed by Cu with a concentration of 9 mg/kg, Mn and Se have the same concentration of 6.5 mg/ kg. e concentrations of other elements ranged between 0.165 and 4.8 mg/kg. All the elements are within the range of the global average of minerals in the soil except mercury, cadmium, and selenium, where their concentrations are 16, 4, and 21 times higher than the permissible limit in the soil, and molybdenum exceeded the permissible limit in this site with a slight increase. On making a comparison of concentrations of minerals in the three sites (A, B, and C) in this area the concentrations of minerals at site B, are the highest for all minerals except that of selenium, the highest concentration of selenium observed at the site C. e results show that the mineral content at site C is higher than that at site A. e decreasing order of observing minerals at sites was A < C < B. e highest concentrations of minerals at the three sites are iron, copper, arsenic, and manganese, respectively. e concentration of arsenic in the soil at site B is higher than that at sites A and C, which indicate that the safe limit is exceeded in the soil at the site B. e concentration of molybdenum also exceeded the recommended limit in the soil at the sites C and B only. e concentrations of mercury, cadmium, and selenium exceeded the permissible concentration limit in the soil at three sites, while the concentrations of the rest of the minerals are within the allowed permissible limit.

Metals at Sewage Soil of Qassim.
e concentration of the mineral in the soil at sites A, B, and C of Qassim region is shown in Table 2.
e concentration of Fe in the soil is 550 mg/kg at sewage site A, which indicates the highest one, followed by Cu; the lower one is that of Mg at ranged from 8.5 to 7 mg/kg. e decreasing order of concentrations of minerals was Ti > Se > Ni > As > Pb > Mo > Cr > Zn > Co > Hg > Cd > Be > and V. e concentrations of all minerals in the soil within the allowed limit except that of Hg, Cd, and Se, which are 12, 4, and 16, times higher than the global average of metal concentration [49], respectively. e  e concentrations of all minerals at site B are within the allowed limit except that of mercury, arsenic, cadmium, and selenium, which have higher levels than the global average value of minerals in the soil. e mineral amount in the soil varied with respect to the site C. e concentrations of Fe and Mn in the soil at site C are 1900 and 30.5 ppm, respectively, while the concentrations of other minerals studied at site C ranged from 0.18 to 6 ppm. e concentrations of all minerals in the soil at site C are within the safe allowed limit in the soil except that of mercury, cadmium, and selenium are 13, 10, and 20 times higher than the global average value of minerals in the soil, respectively. Molybdenum and arsenic exceeded the recommended limit in soil when comparing the mineral content of three sites (A, B, and C). e results shown in Table 2 indicate that the concentrations of all minerals in the soil at site C are significantly highest. e increasing order of minerals content in Qassim region is B < A < C. e high concentration of metals at site C could be due to human factors and the influence of winds in this region. Iron metal represents the highest concentration of minerals at the three sites (A, B, and C) and a significant increase in manganese concentration was observed at site C which is 30.5 mg/kg as compared to its concentration at sites B and A which are 7 and 5.5 ppm, respectively. e concentration of Copper is high at the three sites, and moderate concentrations of arsenic and selenium are observed. e concentrations of all minerals were less than the permissible values in the soil except for mercury, cadmium, and selenium whose concentration exceeded the recommended limit in the soil of the three sites (A, B, and C), while arsenic exceeded the permissible concentration at the two sites (C and B). Only, the molybdenum concentration exceeded the permissible safe limit in the soil at site C.

Metals at Sewage Soil of Medina.
e mineral content of Medina region in the soil at sites (A, B, and C) is shown in Table 2, indicating that the concentrations of mineral in the soil at three sites are different. e concentrations of Ti, Fe, Cu, and Mn in the soil at site A are 1300, 19.5, 16.5, and 11 mg/kg, respectively, which indicate high concentrations. e concentrations of Ni and As at site A are 5.5 and 4.7 mg/ kg, respectively, which indicate moderate concentration, while the concentrations of the other metal studied at site A ranged between 0.165 and 3 mg/kg. e concentrations of all minerals in the soil are less than the corresponding value in the soil [49], except that of Se, Cd, and Hg, which are 14, 6, and 18 times higher than the permissible concentration in the soil recommended limit, respectively, while other minerals are within the safe limit in the soil. Very high concentrations of Fe, Mn, Cu, and Ti are 5000, 100, 28, and 19 mg/kg, respectively, in the soil observed at site B. A moderate concentration ranging between 0.165 and 3 mg/L was observed at site B. By comparing the concentrations of minerals in the soil at site C, the results showed a large difference in the concentrations of minerals in the soils due to the large disparity in the concentration of Fe, Mn, Ti, and Cu which are 4350, 70, 28, and 21 mg/kg, respectively, compared with the concentration of Hg, Be, V, and Cd which are 0.485, 0.24, 0.7, and 0.9 mg/kg, which indicate that the concentrations in the soil are within the safe and permissible limit (<1 mg/kg) except that of Hg, Mo, Cd, and Ce which have highest concentration 16, 2, 15, and 27 times higher than the order of limit in the soil. e results shown in Table 2 and Figure 1 indicate that the concentrations of all minerals in three cities at site B are the highest, except that of titanium, with the highest concentration of it (28 mg/kg) observed at site C. e decreasing order of minerals content in Medina region is B < A < C. e results of the study indicated that iron, manganese, titanium, and copper are the most abundant minerals in the three areas. e concentration of manganese in the soil at site A is 16.5 mg/kg and in the soil at site is 100 mg/kg. Moderate concentrations of minerals in the soil at the three sites are nickel, chromium, zinc, arsenic, and silicon, while the rest of the minerals have lower concentrations (in the range between 0.25 and 5.5 mg/kg). e concentration of mercury, molybdenum, cadmium, and selenium exceeded the global average concentration, while the concentration of other metals remain within the permissible limit, which indicated safety in the soil.

Comparison of Mineral Concentrations at Different Sites.
e results shown in Table 3 indicate that differences in mineral concentration depend on their location at the stream of the sewage. e highest concentration of all minerals was observed in the soil at site B of Riyadh and Medina and site C of Qassim. e highest concentration was observed in Fe (5000 mg/kg) at site B of Medina, the lowest value is 420 mg/kg at site B of Qassim, indicating the prevalence of iron metal in three regions studied. Iron having a high concentration irritates the digestive system and changes the taste of water by promoting iron bacteria [50]. A similar trend was observed in Cu (as an essential nutrient) in the soil close to the sewage stream, indicating contaminated soil. e exposure to copper concentrations for long periods causes liver and kidney and anemia diseases [51]. e third mineral abundant was observed in Mn at site B of Medina and site C of Qassim. Eating Manganese has a daily need in a small amount that is important to maintain good health [52]. A high concentration was observed in Ti at the three sites in Medina region and at three sites of Riyadh and Qassim. e concentration of Cr is ranging between 1.75 and 5.5 mg/kg at all sites of three regions, chromium is considered a toxic metal to all living organisms. e level of toxic chromium in the soil is 50 parts per million [53]. e concentration of Ni at all sites ranged between 2.7 and 10.5 mg/kg. Nickel is considered a human carcinogen when International Journal of Analytical Chemistry 5 ingested in higher than normal concentrations. Nickel is the main cause of allergic contact dermatitis, especially for women [54]. Human inputs such as manure and fertilizers contain lower levels of nickel and chromium than those already in the soil [55]. e concentration of Zn ranged between 0.75 and 4.8 mg/kg at all sites. Zinc is an essential element, but high levels of it can cause adverse health effects. e concentration of Co and Pb is low and moderate, respectively, and the least concentration of Be and V were observed at all sites studied. e minerals in all the locations of the studied areas were less than the general average concentration according to Lindsay 1979 with the exception of mercury metal, whose concentration is within the range 0.365 to 0.55 mg/kg, exceeded the permissible limit in all regions. e level of molybdenum also exceeded the permissible limit in all sites, whose concentration ranged between 2.3 and 4.3 mg/kg, except at sites B and A of Qassim region and site A of Riyadh region. Molybdenum is an essential element in animal and plant nutrition [56]. e concentration of As exceeded the permissible limit in the soil at all sites except at site A of Medina region, at site A of Qassim region, and at site C of Riyadh region. Arsenic is the main constituent of some pesticides and fertilizer substances of soil [57]. e concentration of Cd is higher than the permissible and recommended limit in the soil at sites. e highest value is 8.5 mg/kg in the soil at site B of Medina region, the lowest concentration is 4.8 mg/kg was observed at site A of Qassim region. Cadmium is a highly toxic metal, that cause many symptoms such as nausea, vomiting, difficulty breathing, convulsions, and loss of consciousness. Chronic exposure to high doses of cadmium causes anemia, cardiovascular disease, kidney problems, and high blood pressure [58]. e concentration of Se (4.05-8.5 mg/kg) exceeded the limit at all sites studied. e increase in selenium concentration may be due to the addition of selenium to fertilizers. Precipitation also plays a key role in determining the surface soil level content [59]. In general, the increasing order of concentration of minerals was Be < V < Cd < Hg < Mo < Co < Zn < Pb < Cr < Se < As < Ni < Ti < Mn < Cu < Fe at all sites, respectively. Table 3 is a summary of the minimum, maximum, average, and standard deviation of the number of metal ions in soil samples collected from sanitation sites for three regions of the Kingdom of Saudi Arabia. By looking at the results of Table 3, we find the discrepancy in the range of all distributions of minerals compared with  International Journal of Analytical Chemistry their means, respectively. It is an indication of the contamination of the sample with these minerals studied except for cadmium, arsenic, selenium, molybdenum, and mercury. e decreasing trend of averages of metal levels was as follows: As > Se > Hg > Mo > Cd mg/kg concentrations [59,60]. Table 4 is a summary of the minimum, maximum, mean, and standard deviation for heavy items in 30 soil samples collected at treated wastewater basin soil of Riyadh, Medina, and Qassim, Kingdom of Saudi Arabia. e enrichment factors (EF) of Cr, Ti, V, Mn, and Zn concentration in the soil as shown in Table 4 ranged from 0.06 to 1.91 (EF < 2) in three regions studied, which indicates that the soil is uncontaminated by these elements, and metals are entirely to crustaceans and natural processes. e enrichment factors (EF) of Be and Ni concentration ranged from 2 to 5 (2 < EF < 5) at site of Riyadh and Qassim, which shows moderate fer-

Assessment of Heavy Metal Pollution.
e results of Pollution Index (PI) values of heavy elements of Riyadh, Qassim, and Medina are shown in Table 5 and Figures 3 and  4. Table 5 is a summary of the low, high, and mean values of all heavy values elements found in the soil at site B of Riyadh, Qassim, and Medina regions.
e Pollution Index (PI) values of Ti, Cu, Ni, Pb, Cr, Zn, Co, Mn, Be, and V ranged from 0.0010 to 0.9000 (PI < 1) with an average range between 0.0012 and 0.3704, which indicate that the soil is unpolluted. e PI value of Hg, Mo, and As of Riyadh and Medina ranged from 1.0000 to 1.6538 (PI > 1) with an average range between 0.8205 and 1.1375 which indicate that the soil is slightly polluted in these two regions, while the PI values of these elements of Qassim are PI < 1 which indicate that the soil is unpolluted. e value of As of Medina is 3.3333 (PI > 1) which indicate that the soil is strongly polluted, while its presence in the soil of the regions of Riyadh and Qassim is considered unpolluted. e PI value of Se is ranged from 6.7500 to 14.1667 (PI > 1) with an average of 10.0278, which indicate that the soil is very strongly polluted.

Quantitative Measurement of Mineral Pollution.
Quantitative measurement of mineral pollution of the soil studied is shown in Table 6 and Figure 5. e geographical accumulation index (I geo ) value of Mo is 0.1409 (I geo < 0) of Riyadh and Qassim, which indicate that the soil is unpolluted. e I geo value of Cd is 1.1520 (I geo > 1) of Medina region which indicate that the soil is moderately polluted, while it did not give pollution in the regions of Riyadh and Qassim. Cd is considered one of the most dangerous toxic minerals and accumulates significantly in soil samples. e I geo value of Se is 3.2395 (I geo > 1) of Medina region which indicate that the soil is strongly polluted, while its cumulative geographical index decreased in the regions of Riyadh and Qassim, which amounted to 2.6114 and 2.1699, respectively, that classified the pollution of this mineral in these two regions as moderately to highly polluted. e I geo values of the rest of the minerals in the three regions studied are indicated that the soil is unpolluted as shown in Figure 5.
e calculated values refer to the (PI) pollution index and geographic cumulative index (I geo ) from medium to high    International Journal of Analytical Chemistry pollution levels from Se in the soil of all regions studied. It was also found that this soil was polluted with As of Medina region. While it was slightly to moderately polluted for both Mo and Hg in most regions studied.

Conclusion
A sensitive, reproducible, and relatively simple ICP method was developed to screen and quantify heavy metals that cause soil pollution. Samples collected from regions without any information about levels of contamination of the soil. From the collected samples, around 31% of samples (mercury, molybdenum, arsenic, cadmium, and selenium) found whose concentration exceeded the permissible and recommended limits. is finding demonstrated the importance of soil constituents in fertilization and cultivation processes.

Data Availability
e data used to support the findings of this study are included within the article. e used materials are available in the Princess Nourah bint Abdulrahman University store.

Conflicts of Interest
e author declares no conflicts of interest.  International Journal of Analytical Chemistry 9