Globally, groundwater accounts for nearly 97% of the Earth’s available freshwater and is stored beneath the surface in geological formations (Albbanqeeyah et al., 2024; Ramos et al., 2021). With rapid population growth, urban expansion and socioeconomic development, groundwater particularly well water has become a vital resource for domestic consumption and agricultural irrigation, especially in arid and semi-arid regions (Beyene et al., 2019; Guo et al., 2021). Agricultural irrigation is considered one of the most sensitive components of water resource management systems due to its high demand and direct impact on food security (Vranešević  et al., 2024; Sharma et al., 2016). Globally, agriculture consumes approximately 70% of total freshwater withdrawals, while nearly 20% of cultivated land depends on irrigation practices (Vranešević  et al., 2024). In Iraq, particularly in areas surrounding Fallujah City within Anbar Governorate, groundwater extracted through wells constitutes a primary source for both drinking and irrigation purposes (Al-Kubaisi  et al., 2025).
       
The conservation and sustainable management of groundwater resources are therefore essential, especially in regions where agricultural productivity and land sustainability are highly dependent on well water. Degradation of groundwater quality directly affects soil properties and crop productivity, leading to serious environmental and economic consequences (Maghrebi et al., 2021; Noori et al., 2021). It has been reported that the use of poor-quality irrigation water adversely affects nearly 20% of agricultural soils worldwide, accelerating processes such as salinization, alkalization and waterlogging (Payen et al., 2016). In arid regions such as Anbar Governorate, declining groundwater availability and quality further exacerbate water scarcity and limit agricultural development.
       
Groundwater and well water are often characterized by elevated concentrations of dissolved ions originating from the weathering and dissolution of geological materials, which increases salinity levels and poses risks to agricultural soils (Brhane et al., 2024). Numerous studies have demonstrated that the chemical composition of groundwater is governed by a combination of natural and anthropogenic factors, including lithology, soil-rock interactions, geochemical processes, climate, recharge conditions and topography, in addition to human activities such as agricultural practices, industrial discharge, land-use change and urban expansion (Albbanqeeyah et al., 2024; Vranešević  et al., 2024; Gu et al., 2017; Rawat et al., 2019). These interacting processes often result in groundwater quality deterioration, rendering it unsuitable for various uses, particularly irrigation (Rao et al., 2021; Gugulothu et al., 2022). In regions lacking good-quality surface water, farmers are compelled to use sodic groundwater for irrigation, posing serious risks to soil health and the environment (Pradeepa et al., 2019).
       
Geochemical processes controlling groundwater quality are largely influenced by mineral dissolution, ion exchange, evaporation, flow paths and recharge mechanisms (Li et al., 2013; Saravanan et al., 2015; Subba Rao et al., 2017; Gugulothu et al., 2022). In arid and semi-arid regions, including Anbar Governorate in Iraq, intensive use of well water combined with anthropogenic pressures-such as excessive application of chemical fertilizers and pesticides, inadequate drainage systems, urban and industrial development and animal waste disposal-further degrades the physical and chemical characteristics of groundwater (Koffi et al., 2017; Wagh et al., 2019; Gugulothu et al., 2022). Such degradation not only affects soil productivity but also poses risks to human health and economic sustainability, ultimately constraining agricultural output.
       
Water quality is a critical determinant of its suitability for irrigation, as groundwater chemistry directly influences soil fertility, structure and permeability, thereby affecting crop yields (Guo et al., 2021). These effects arise mainly from soil-water interactions, particularly ion exchange processes (Bian et al., 2018; Dev and Bali, 2019; Guo et al., 2021). Elevated sodium concentrations in irrigation water are especially problematic, as they reduce soil hydraulic conductivity, decrease permeability and impair internal drainage, ultimately leading to soil degradation (Guo et al., 2021; Sahab et al., 2025). Consequently, evaluating the physicochemical properties of groundwater is essential before its use in irrigation. Previous studies have assessed irrigation water quality based on parameters such as electrical conductivity (EC), total dissolved solids (TDS), pH, total hardness (TH), salinity indicators, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), turbidity, major cations and anions, nutrients and selected heavy metals (Guo et al., 2021).
       
In Fallujah City, located in Anbar Governorate, Iraq, local communities predominantly rely on well water for irrigating agricultural lands. However, the quality of this water has not been comprehensively evaluated and its suitability for irrigation remains uncertain (Sahab et al., 2025). The study area is exposed to several potential sources of groundwater contamination, including sewage leakage, uncontrolled solid waste disposal, excessive use of chemical fertilizers, animal waste and industrial effluents. Despite the importance of groundwater quality assessment in this region, there is a lack of systematic studies addressing the physicochemical characteristics of well water and its appropriateness for agricultural use.
       
Therefore, the present study aims to evaluate the suitability of well water for agricultural irrigation in selected areas of Fallujah City by analyzing key physicochemical parameters from five irrigation wells. The investigated parameters include EC, TDS, pH, turbidity, dissolved oxygen (DO), total hardness (TH), soil texture distribution, major cations (Ca²⁺, Mg²⁺, Na⁺), major anions (Cl^-, SO₄^2-, HCO₃^-, NO₃^-, PO₄^3-), sodium adsorption ratio (SAR) and selected heavy metals (B, Cd and Pb). The findings of this study are expected to provide a scientific basis for groundwater management, support the implementation of appropriate treatment and mitigation strategies and contribute to sustainable agricultural development in the region.

Study area
 
The study was conducted in Fallujah City, located in Anbar Governorate, western Iraq (33°35'N, 43°78'E) Fig 1. The study area covers approximately 40 km² and lies at an elevation of about 44 m above sea level. The region is characterized by a hot desert climate, with mean annual rainfall of approximately 150 mm and high evaporation rates. Five groundwater wells commonly used for agricultural irrigation were selected from different locations: Al-Halabsa, Al-Saqlawiya, Al-Naimiya, Al-Sajr and Al-Karma. The depths of the selected wells ranged between 9 and 20 m, representing the shallow groundwater system exploited for irrigation in the area.


 
Sample collection
 
Groundwater and soil samples were collected during February and April 2024 to represent two contrasting seasonal conditions: late winter (higher recharge potential) and early spring (increased agricultural activity). Prior to sampling, each well was purged continuously for 20 minutes to remove stagnant water and ensure sample homogeneity Fig 2. Water samples were collected in pre-cleaned and sterile polyethylene bottles (1 L capacity). Soil samples were collected from the irrigated zones adjacent to each well at a depth of 0-30 cm using clean tools.

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Samples intended for microbiological (coliform) analysis were collected separately using sterile containers and appropriate adsorbent materials. All samples were immediately labeled as B1-B5 for groundwater samples and C1-C5 for soil samples, preserved at 4°C in insulated containers and transported to the laboratory on the same day for physicochemical analysis Table 1.
 
Physical analyses
 
Total hardness (TH) of groundwater samples was determined using the standard EDTA titrimetric method. Soil particle-size distribution (sand, silt and clay fractions) was determined using the hydrometer method after the removal of carbonates and organic matter, following standard soil analysis procedures Table 1.


 
Chemical analyses
 
Table 1 showed some of chemical parameters including Electrical conductivity (EC), pH, total dissolved solids (TDS), turbidity and dissolved oxygen (DO) were measured using calibrated digital meters according to standard methods. Major cations (Ca²⁺, Mg²⁺, Na⁺) and anions (Cl^-, SO₄^2-, HCO₃^-, NO₃-, PO₄^3-) were analyzed using a combination of titrimetric methods, flame photometry and spectrophotometry, following standard analytical protocols.
       
Soil chemical properties were determined using a soil-water extract prepared at a ratio of 1:5 (w/v), after thorough shaking and filtration. Sodium adsorption ratio (SAR) was calculated using the concentrations of Na⁺, Ca²⁺  and Mg²⁺  according to Richards (1954). Heavy metals, including lead (Pb), cadmium (Cd), boron (B) and copper (Cu), were measured using atomic absorption spectrometry (AAS).
 
Quality control and data validation
 
Quality assurance procedures included instrument calibration using certified standard solutions prior to analysis, duplicate sample measurements and the use of reagent blanks. The ionic balance error between total cations and anions was maintained within ±5%, indicating acceptable analytical accuracy. The obtained results were evaluated and compared with the maximum allowable limits recommended by the World Health Organization (WHO) for irrigation water quality.

The physicochemical characteristics of the analyzed groundwater samples (B1-B5) and soil extracts (C1-C5) are presented in Table 2-4. The pH of groundwater samples ranged from near-neutral to slightly alkaline values (6.9-7.8), with a noticeable alkaline tendency in samples B4 and C4. This behavior is primarily attributed to elevated bicarbonate concentrations, which exert a buffering effect on groundwater and soil systems, particularly in carbonate-rich geological environments. Similar pH ranges have been reported for groundwater in arid and semi-arid regions of Iraq and neighboring countries. All measured pH values fall within WHO guideline limits, indicating no immediate restriction for irrigation or domestic use. Soil extracts also exhibited weak alkalinity, commonly associated with carbonate dissolution and mineral weathering processes in calcareous soils.



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Electrical conductivity (EC) and total dissolved solids (TDS) values reflected relatively low to moderate mineralization levels in the investigated groundwater. Although EC and TDS values varied spatially among wells, the overall salinity hazard can be classified as low to moderate, suggesting limited salt accumulation and minimal risk of soil salinization under current irrigation practices. This indicates that the groundwater is generally suitable for agricultural use; however, localized increases in salinity cannot be excluded under long-term irrigation without proper drainage management.
       
Dissolved oxygen (DO) concentrations in groundwater samples B1-B4 (6.04-6.82 mg/L) indicate well-aerated conditions and limited organic pollution, consistent with shallow aquifer recharge and active water renewal. In contrast, the lower DO value observed in B5 (4.19 mg/L) may reflect localized stagnation, reduce hydraulic connectivity, or increase microbial oxygen consumption due to organic matter inputs. In soil extracts, DO values were consistently low (0.36-1.5 mg/L), which is characteristic of soil environments where oxygen diffusion is restricted and microbial respiration dominates at the soil–water interface.
       
Turbidity levels in groundwater samples were generally low (0.6-3.6 NTU) and below the WHO guideline value of 5 NTU, confirming the relatively clear nature of the well water and the absence of significant particulate contamination. In contrast, turbidity values in soil extracts were extremely high (175-550 NTU), particularly in samples C3 and C4. This phenomenon is primarily related to the dispersion of fine clay particles and suspended soil colloids during extraction, rather than direct groundwater pollution. Similar observations have been reported in clay-rich soils where physical disturbance enhances particle suspension.
       
Total hardness values were high in several groundwater samples (370-1730 mg/L) and markedly elevated in soil extracts (544-3064 mg/L), with samples B4, B5 and all soil extracts exceeding recommended guideline limits. This high hardness is mainly attributed to the dissolution and leaching of calcium and magnesium carbonates from the dominant carbonate lithology of the region. Although high hardness does not pose a direct hazard for irrigation, prolonged use of such water may influence soil permeability and nutrient balance. No consistent relationship was observed between turbidity and hardness, indicating that these parameters are governed by independent geochemical processes.
       
Soil texture analysis demonstrated substantial spatial variability across the study area. Samples B1 and B5 were classified as sandy clay loam, B2 as loam, B3 as silty loam with a relatively high clay fraction and B4 as clay loam, as confirmed using the USDA soil texture triangle. The dominance of clay-rich textures in several locations is likely linked to Euphrates floodplain deposits, characterized by fine sediments, low permeability and poor drainage. Nevertheless, soils from the Saqlawiyah area exhibited relatively better structure and fertility compared with other locations, enhancing their suitability for crop growth. Elevated cation exchange capacity (CEC), particularly in the clayey soils of Al-Halabsa and Al-Karma, enhances nutrient retention but may also increase the potential for accumulation of contaminants and heavy metals.
       
Sodium adsorption ratio (SAR) values were low (0.189-0.599), indicating an absence of sodicity hazards and favorable conditions for maintaining soil structure under irrigation. Calcium was the dominant cation, followed by magnesium and sodium, a distribution that supports soil aggregate stability. Anion concentrations were generally within acceptable ranges; however, elevated bicarbonate levels in samples B2 and B4 may, over prolonged irrigation periods, alter soil chemical equilibrium and nutrient availability.
       
Nitrate concentrations (1-15 mg/L) remained well below the WHO guideline limit, yet the relatively higher nitrate level in sample B3 suggests localized anthropogenic influence, most likely from fertilizer application or agricultural runoff. Although current levels do not pose a critical risk, continued inputs could increase contamination potential over time. Phosphate concentrations were low (0.08-1.60 mg/L); nevertheless, sustained fertilizer use may lead to gradual enrichment of soil and groundwater systems.
       
Trace elements, including boron, cadmium and lead, were detected at concentrations below WHO permissible limits, indicating no immediate environmental or health concern. Overall, groundwater in the Fallujah region can be considered generally suitable for irrigation. However, site-specific variability, combined with elevated hardness, bicarbonate levels and localized anthropogenic influences, highlights the need for continuous monitoring, improved drainage practices and rational fertilizer management to ensure long-term agricultural sustainability and environmental protection.

This study evaluated the suitability of groundwater from five wells in Fallujah City, Iraq, for agricultural irrigation through an integrated assessment of physicochemical properties of well water and soil extracts. The results demonstrated that most measured parameters, including pH, EC, TDS, major cations, sodium adsorption ratio and trace metals (Pb and Cd), generally complied with international guideline limits, indicating that the investigated groundwater is largely suitable for irrigation under current conditions.
       
Despite the overall acceptable water quality, elevated total hardness and bicarbonate concentrations observed in some wells, together with high turbidity and mineral content in soil extracts, highlight site-specific hydrogeochemical constraints that may influence soil properties under long-term irrigation. Furthermore, the presence of measurable nitrate, phosphate and boron concentrations-although below critical thresholds-suggests localized anthropogenic influences, likely related to agricultural practices and wastewater infiltration, which could pose future contamination risks if not properly managed.
       
Accordingly, continuous and systematic monitoring of groundwater quality is recommended, with particular emphasis on salinity indicators, nutrient dynamics and trace elements. Improving drainage systems and promoting rational fertilizer use are essential measures to prevent soil degradation and safeguard groundwater resources. These actions will support sustainable agricultural development and long-term environmental protection in the Fallujah region.

The present study was supported by College of Agriculture, University of Anbar.
 
Disclaimers
 
This article was exclusively written by the authors. The opinions expressed are not necessarily those of their institutions.
 
Informed consent
 
There were no human or animal subjects in this study. All sampling and laboratory works were carried out according to environmental and lab safety rules.

No funding sources had a direct influence on the conduct or publication of this article and the authors disclose no conflicts of interest.