Banner
Current IssueEditorial BoardOnline First ArticlesArchive
Current IssueEditorial BoardOnline First ArticlesArchive

Full Research Article

Assessment of the Risks of Heavy Metal Contamination in Irrigation Water, Soils and Crops in Agricultural Fields Near Some Oil Fields

A
Al-Aamel1
A
Ali Nasser1,*
https://orcid.org/0009-0006-4660-4741
A
Al-Taie1
https://orcid.org/0000-0003-4800-6113
S
S.A. Ahmed1
A
Ahmed H. Sadeq1
https://orcid.org/0009-0004-1181-8032
L
Lara Basheer Yaser2
https://orcid.org/0009-0002-1201-0348
1Environmental Research Center, University of Technology- Iraq, 10066, Baghdad, Iraq.
2Department Plant Protection, College of Agricultural Engineering Sciences, University of Baghdad, 10071, Baghdad, Iraq.

ABSTRACT

Background: The primary objective of the current study is to evaluate the environmental risks and heavy metal contamination in irrigation water, soil and crops cultivated in agricultural fields near certain oil fields.

Methods: Atomic absorption spectrometry was used to test and analyze water, soil and plant samples for Cadmium (Cd), Chromium (Cr), Lead (Pb), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni) and Zinc (Zn).

Result: The samples extremely low concentrations of Cd, Cr and Pb were found in the laboratory, indicating that the local environment is free of these heavy metal contaminants. Fe was the dominant pollutant, exhibiting severely high concentrations, soil at the Amara site (BS) contained Fe at 85,369.62 mg/kg, far exceeding the WHO safety limit. Mn also showed significant contamination, with crop levels reaching 821.97 mg/kg, well above recommended guidelines. In contrast, concentrations of Cu (13.21-83.15 mg/kg), Ni (3.44-86.26 mg/kg) and Zn (52.88-174.40 mg/kg) in water, soil and crop samples were found to be within the permissible limits according to international standards. This stark divergence confirms that the multi-element contamination, as identified by the composite index, is primarily driven by Fe and Mn. The significant bioaccumulation of these metals in crops Fe at 645-673 mg/kg versus a 50-300 mg/kg standard, highlights a critical pathway from soil to the food chain. These findings unequivocally point to anthropogenic activities from the oil fields as the source of pollution, posing a direct threat to agricultural safety and potential human health risks. 

INTRODUCTION

Heavy metals accumulate in soils, especially metals that are not biodegradable or thermally degradable, which affects the quality of cultivated agricultural soils and pollution levels reach the food chain, This accumulation comes from natural sources or various human activities such as poor drainage of sewage or the presence of oil fields within cities and incorrect methods of waste disposal and excessive use of chemical pesticides to combat pests (Kumar et al., 2019). Many studies have indicated that heavy metals in crops such as Wheat, Rice and vegetables in addition to animals, can spread and accumulate and thus reach the population, causing health problems for humans (Mishra et al., 2018; Ali et al., 2020; Vyas and Shukla, 2020; Zakaria et al., 2021). It has been found that continuous exposure to cadmium (Cd) causes serious problems such as lung cancer, kidney damage and blood pressure disorders (Sawut et al., 2018). There are serious worries that heavy metals could enter the food chain from oil fields due to their close proximity to agricultural fields in some places. The source mostly determines the behavior and distribution of toxic metals, which include lead, chromium and cadmium. These metals can cause developmental abnormalities, organ damage and cancer (Bhardwaj, et al., 2022), High concentrations of Nickel (Ni) in water and soil lead to its reaching the human body through absorption by plants and may lead to health risks such as allergies, lung damage and cancer (El-Naggar et al.,  2021). In addition to being a carcinogenic metal, Lead (Pb) is regarded as a hazardous metal that spreads, builds up and poses health hazards like diabetes, heart problems and stunted growth (Gundacker et al., 2021). (Tumolo et al., 2020) also stated that all living organisms are affected by Chromium (Cr), which poses a risk to human health due to its effects on DNA damage and the development of cancer. Depending on exposure levels, it can cause skin irritation. It is found in groundwater and groundwater, as well as areas near chemical and tanning facilities. Oil extraction and processing are potential anthropogenic sources of a wide range of elements. These include essential elements such as Copper (Cu), Zinc (Zn), Iron (Fe) and Manganese (Mn), which can become hazardous contaminants at elevated concentrations, disrupting soil microbial ecosystems and posing non-carcinogenic health risks such as neurotoxicity and gastrointestinal diseases. The potential of Cu to oxidize and degrade numerous vital enzymes in soil microorganisms makes it dangerous and a high concentration of Cu in the soil can endanger the ecosystem and a variety of creatures that live there. In terms of the diversity and richness of microorganisms, its high concentrations in the soil may be hazardous to the environment and impact soil functioning (Fagnano et al., 2020). For many livings things Fe is a necessary nutrient and a vital element. It is regarded as a secondary contaminant and as its concentration in soil and water rises, it may affect human health by affecting the liver, pancreas, blood cells, stomach issues and nausea. In addition, vegetables with high iron content are ugly and black (Akhtar et al., 2022). In trace amounts Mn a naturally occurring oxidizing and reducing mineral, is a necessary nutrient, elevated concentrations of it in soil and water can enter the food chain and result in non-cancerous health issues like neurotoxicity symptoms in people (Erikson and Aschner, 2019). Zinc (Zn) also plays an important role in stimulating many growth and reproduction enzymes (Imsong et al., 2023), as it is linked to DNA and cell division in moderate quantities, while increasing its concentration leads to poor appetite, diarrhea, vomiting, nausea and headaches and affects the human immune system. Therefore, its concentration should be limited in water and soil suitable for agriculture (Natasha et al., 2022). Consequently, this study provides a comparative environmental risk assessment to determine the concentrations of eight heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in irrigation water, soil and crop samples taken from agricultural fields close to two separate oil fields (Ajil in central Iraq and Amara in the south) and evaluates the results according to international safety standards.
 

MATERIALS AND METHODS

Study site
 
The experiment was conducted in the year 2023-2024, all experimental tests were conducted at the Environmental Research Center, University of Technology, Iraq and two sites were selected to conduct the study. The first is the agricultural fields near the Ajil oil field (A), located in Salah al-Din Governorate in central Iraq, 180 km north of the capital, Baghdad (Latitude 34.50o N, Longitude 43.20o E).  The second is the agricultural fields near the Amara oil field (B), located in Maysan Governorate in southern Iraq, 320 km southeast of the capital, Baghdad (Latitude 31.85o N, Longitude 47.15o E).
 
Sample collection
 
Samples were collected from agricultural fields and included: Irrigation water (W), soil (S) and different crops (C), with four replicates for each sample from both locations (A and B). The agricultural fields are approximately 5 km away from the oil fields, separated by an earthen barrier to prevent farmers from using the lands near the oil fields for agricultural purposes (Fig 1). Oil processing operations are accompanied by secondary gases that are burned and released into the atmosphere (Fig 2), causing air pollution in the surrounding areas and it is expected that the cultivated crops will be polluted by it during breathing processes (Ukaogo and Onwuka, 2020), The water used to get rid of the oil salinity in the fields is poured into the surrounding soil without treatment (Fig 3). This poses a long-term danger, as this water, with the heavy element particles it carries, may penetrate the groundwater and reach the soil of the agricultural fields nearby, causing pollution. Consequently, the pollution reaches the cultivated crops and from there to the human consumer (Rashid et al., 2023). Water samples were taken from wells used for irrigation, soil was collected from a depth of 25 cm and crop samples were collected randomly without specifying the crop type, including the entire plant.

Fig 1: Agricultural fields from which samples were collected.



Fig 2: Gases associated with oil processing operations.



Fig 3: The soils adjacent to the oil fields.



Examination methods
 
Standard testing methods were used to test the heavy metals of the samples. Water samples were filtered using filter paper and preserved by adding (1 ml) of nitric acid to prepare them for testing, while soil and plant samples were digested by adding a mixture of nitric acid (10 ml) and hydrochloric acid (30 ml) to (0.5 g) of the sample after drying and grinding it, then it was heated at 60°C for two hours (Fig 4), filtered and the volume was completed to (100 ml) with deionized water (Bialkowski and Proskurnin, 2019), Heavy elements (Cd, Ni, Pb, Cr, Cu, Fe, Mn and Zn) were examined at the Environmental Research Center/University of Technology using an Atomic Absorption Spectroscopy AAS 6300 from Shimadzu, Japan, according to the approved standard method 3030 E.

​

Fig 4: Digestion of soil and plant samples.

RESULTS AND DISCUSSION

Test results
 
Tables 1, 2 and 3 show the results of heavy metal tests for the samples used in the study as follows:

Table 1: Heavy metal test results for water samples*.



Table 2: Results of heavy metal tests for samples from the Ajil oil field site (A)*.



Table 3: Results of heavy metal tests for samples from the Amarah oil field site (B)*.


 
Water samples
 
The results of the Table 1 indicate that the Ajil site (AW) recorded the highest concentrations, as Fe reached 2526.48 µg/L, followed by Mn: 503.13 µg/L, then Zn: 65.03 µg/L, Ni: 40.48 µg/L and Cu: 17.53 µg/L, while the concentrations of Cd, Cr and Pb were below the detectable limits (0.00 µg/L). The Amara site (BW) recorded the following concentrations: Fe: 15662.80 µg/L, Mn: 471.35 µg/L, Zn: 75.30 µg/L, Ni: 53.70 µg/L, Cu: 17.08 µg/L. Meanwhile, the concentrations of Cd, Cr and Pb were below the detectable limits (0.00 µg/L).
 
Soil and crop samples
 
The results of Table 2 showed that the soil samples (AS) at the Ajil site (A) had the highest concentration of Fe: 71859.23 mg/kg, followed by Mn: 942.85 mg/kg, Zn: 72.88 mg/kg, Ni: 17.08 mg/kg and Cu: 10.62 mg/kg. While the concentrations of Cd, Cr and Pb were undetectable (0.00 mg/kg). As for crop samples from the same site, Fe recorded the highest concentration of 673.40 mg/kg, followed by Mn: 759.79 mg/kg, Cu: 16.17 mg/kg, Zn: 56.67 mg/kg and Ni: 3.71 mg/kg. Concen-trations of Cd, Cr and Pb were undetectable (0.00 mg/kg).

The results of Table 3 showed that the soil samples (BS) at Amarah site (B) recorded the highest concentration of Fe: 85369.62 mg/kg, followed by Zn: 174.40 mg/kg, Ni: 86.26 mg/kg, Cu: 83.15 mg/kg and Mn: 338.56 mg/kg. The concentrations of Cd, Cr and Pb were undetectable (0.00 mg/kg). As for crop samples (BC) from the same site, Mn recorded the highest concentration of 821.97 mg/kg, followed by Fe: 645.41 mg/kg, Zn: 52.88 mg/kg, Cu: 13.21 mg/kg and Ni: 3.44 mg/kg. Concentrations of Cd, Cr and Pb were undetectable (0.00 mg/kg).

Contrary to expectations, the results indicated that contamination with hazardous elements Cadmium, Chromium and Lead is not present, whether in irrigation water or in soils and cultivated crops. The reason for this is the possible absence of rocks bearing these elements in the studied areas or their absence in the water accompanying production. It may also be due to the distance between agricultural fields and oil fields and the pollutants that accompany them, which was confirmed by Onakpa et al., (2018) and  Awad et al., (2022) were mentioned that keeping agricultural areas away from oil sources could avoid contamination with dangerous metals that could be transferred to food. Several studies have reported that cadmium accumulation in soil and plants typically results from the use of agricultural technology and industrial activities, as well as from sewage sludge, it is also present in soils with low pH (Aslam, et al., 2023). Its direct effect is to inhibit microbial activity and the metabolism of beneficial microorganisms by affecting their respiration, in addition to altering the soil physicochemical properties. It also affects plant physiology by competing with cadmium for the uptake of beneficial plant nutrients (Alengebawy et al., 2021), It also affects plant physiology by competing with cadmium for the uptake of beneficial plant nutrients and The phenotypic effects of cadmium on plants include decreased the size and weight of roots and shoots; cytotoxicity, which results in decreased chlorophyll content and reduced photosynthetic efficiency; and metabolic processes, which include cell damage and chlorosis Hayat et al., (2019).

Particles of chromium are present in the environment and are released by liquid waste from mining, tanneries, construction, painting, photographing, printing and medical industries, Because it pollutes the environment, it is seen as a serious health risk (GracePavithra et al., 2019), Additional environmental sources of chromium include, liquid fuel-powered power plants, waste from industries and rocks that have been worn by air and water (Shahid et al., 2017), Toxic chromium seeps into water bodies and then onto adjacent fields when industrial waste is released into the soil (Coetzee, et al., 2020), Although chromium contamination isn’t an international problem, local biogeochemical cycles may be affected by high levels of this contaminant due to metal penetration into the soil, water, or atmosphere (Yang et al., 2022), Chromium benefits plants at low concentrations, but at high concentrations, it inhibits growth by affecting seed germination and photosynthesis efficiency. It can also damage root cells, leading to plant death and reduced productivity (Ao et al., 2022).

Lead is a toxic heavy metal and a major pollutant that poses health risks when present in water, soil and plants, even at low concentrations (Blanco et al., 2021), This element can be found naturally in a variety of forms, such as lead sulfide or complex ores. Acid rain, car emissions, the burning of petroleum and natural gas and wastewater from homes and businesses are some of the industrial processes that discharge its byproducts into the biosphere (Chowdhury et al., 2022; Kumar et al., 2020). Because lead has detrimental and toxic effects on soil biodiversity and microbiota, it is a problem when it accumulates in water and then soil. In cultivated plants, this results in stress through cell dysfunction, which can lead to weak roots, decreased chlorophyll synthesis, slowed seed germination and overall plant weakening. Additionally, it can build up in specific plant sections and make its way into the food chain, impacting public health and human systems and eventually leading to chronic diseases (Kushwaha et al., 2018).

The positive results in the absence of these elements in the studied areas do not represent concerns from an environmental or health perspective, despite the many studies mentioned above that showed the risk of increased concentrations of the three elements under study, Cadmium, Chromium and Lead. Ongoing research and testing of these components must be done, nevertheless, in the same locations but with different samples and conditions.

The results of the copper element showed that the proportions were within the limit permitted by the World Health Organization and this is a good indicator from an environmental perspective, as the presence of copper within specific concentrations is required due to its importance for plant and human health. It is a double-edged sword, as an increase in its concentrations may lead to harm to the plant or humans (Zhen et al., 2022; Numaan et al., 2024). Copper sources vary depending on the environment. It increases in areas with industrial activity or near oil fields, as the results of these fields release varying levels of various elements, including copper, into groundwater or soil. These elements are then cumulatively transferred to plants and from there to human consumers (Masindi and Muedi, 2018). Sources of copper in the agricultural sector can be due to fertilizers and pesticides used, or from animal waste, which leads to its accumulation in the soil and subsequent uptake by plants (Zhang et al., 2019), Copper toxicity disrupts the ecosystem when present at higher than normal levels. Its presence in soil is affected by several factors, including pH, as it increases in acidic soils and poses a threat to the effectiveness of soil microorganisms (Namee et al., 2023), which play a positive role in decomposing soil organic matter. Its effect occurs through the destruction of cell membranes and consequently, the breakdown of microbial proteins (Wang et al., 2019). Copper can react with other elements, such as zinc, leading to reduced absorption of these elements compared to their free state. High levels of copper can also produce free hydroxyl radicals, which increase levels of reactive oxygen (ROS) species and thus damage plant cells, potentially leading to plant death and reduced yields (Wu et al., 2016), Considering the positive concentrations of copper shown in the current study, we can say that the studied areas are environmentally safe from this element, but continuous monitoring is necessary to avoid the possibility of its increase in different conditions.

While iron showed a significant increase in all samples used in the study, with concentrations exceeding the permissible limit, the cause may be oil pollutants, water associated with production and refining process emissions that settle in soil and waterway (Weldeslassie et al., 2018), or it may be due to natural corrosion of fuel pipes and tanks made of iron (Chukhin and Andrianov, 2022; Mahdi et al., 2023), Many studies indicate that the soil near oil fields is rich in iron due to the dissolution of its compounds in groundwater or the effect of the accompanying organic acids that seep into the soil (Castro et al., 2022). Some plants have a high capacity to absorb heavy elements, which explains why iron is high in plants due to its presence in abundant quantities in water and soil (Al-aamel and Al-maliky, 2023). High iron levels in water cause a change in color and taste, contribute to the formation of sediments, or may interact with some compounds, resulting in toxic substances. High iron levels in soil reduce its fertility due to its effect on the pH level and reduce the absorption of other nutrients (Dietrich and Burlingame, 2020; Dvorak and Schuerman, 2021), as for its high levels in plants, it may cause yellowing of leaves, inhibit growth and accumulate in plant tissues, thus reaching the food chain (Santos et al., 2019).

The results also indicated that the manganese concentration exceeded the permissible limits of international standards. The reason may be the leakage of drilling fluids rich in this element, or associated water, or emissions into the water and subsequently into the soil and then the plants (Sobri et al., 2024), or it may be due to the dissolution of minerals, a decrease in the acidity of the soil, or the use of fertilizers and pesticides containing this element (Dey et al., 2023), This increase leads to the deposition of manganese oxides and has negative effects on beneficial microorganisms, causing an imbalance in the nutritional balance and affecting the low production of cultivated crops (Khoshru et al., 2023), Despite its importance in plant life processes, manganese is required in small quantities. Depending on the availability of manganese, plants must either utilize it efficiently under restricted conditions or detoxify this excess mineral, based on the physicochemical characteristics of the soil, particularly in acidic soils and the redox processes that result in elevated levels of this element, manganese can have a harmful effect on plants when it is present in high concentrations and proportions Rengel, (2015), as for its danger to human health, high concentrations of it lead to problems in the nervous, digestive and reproductive systems (Yin et al., 2021).

These high levels, which could be dangerous if they accumulate over the long term, require a comprehensive analysis of the studied areas to determine the main causes that lead to the rise of this element in these areas and to take some ongoing measures and treatments to reduce the existing pollution.

As for the results of the nickel and zinc elements, they showed that indicated levels lower than the internationally permitted limits, which may be due to the scarcity of natural resources in rock formations, low rates of chemical weathering and their lack of use in large quantities in drilling and production operations (Mudd  and Jowitt, 2022; Aljanabi et al., 2022), This indicates the absence of toxicity from these elements and the safety of the water in the studied areas. These positive results reduce the severity of iron and manganese pollution and emphasize the importance of a comprehensive assessment of heavy elements in areas close to oil fields.

CONCLUSION

This study evaluated the potential environmental risks resulting from heavy metal contamination of irrigation water, soil and crops grown in agricultural areas adjacent to the Ajil and Amara oil fields in Iraq. The results of the experiment revealed that there was contamination resulting from increased Iron and Manganese levels in all types of samples studied, with concentrations exceeding the permissible limit set by the WHO. This contamination is likely the result of industrial activities resulting from oil operations, leakage of production fluids, or perhaps the corrosion of pipelines or leakage of untreated water used in oil fields. In contrast, the results indicated the absence of contamination with highly toxic elements such as Cadmium, Chromium and Lead, as concentrations below the permissible limits were recorded in all samples studied. This may be attributed to the scarcity of sources from local industries such as tanning and chemical industries, in addition to the efficiency of the barrier separating the oil fields from agricultural areas. Concentrations of Copper, Nickel and Zinc also gave readings within the environmentally safe limits in all samples. The combined contamination of Iron and Manganese demonstrates a direct pathway for these contaminants to enter the food chain, potentially posing health risks to crop consumers, including gastrointestinal diseases and neurotoxicity, particularly when exposed to these elements over extended periods.
 
Recommendation
 
Immediately address iron and manganese contamination using soil improvement and bioremediation techniques, monitor and track trends in water, soil and crop contamination in these areas, take strict measures to enforce regulations for the safe disposal of petroleum product and emissions, conduct further studies on the sources of emissions from oil fields and conduct studies of other elements in different agricultural areas to ensure human safety and health.

ACKNOWLEDGMENT

We extend our sincere thanks and gratitude to the Environmental Research Center at the University of Technology for the distinguished scientific and technical support it provided to complete this research. All laboratory tests conducted at the center contributed to reliable results that formed a solid scientific basis for this specialized environmental study. This scientific achievement remains the fruit of the joint efforts of the research team and the distinguished Environmental Research Center, confirming the role of academic institutions in serving environmental issues and sustainable development. 
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided but do not accept any liability for any direct or indirect losses resulting from the use of this content.

CONFLICT OF INTEREST

The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the study’s design, data collection, analysis, decision to publish or manuscript preparation.

REFERENCES


  1. Akhtar, S., Luqman, M., Farooq Awan, M.U., Saba, I., Khan, Z.I., Ahmad, K., Muneeb, A., Nadeem, M., Batool, A.I., Shahzadi, M. and Memona, H. (2022). Health risk implications of iron in wastewater soil-food crops grown in the vicinity of peri urban areas of the District Sargodha. PloS one. 17(11): e0275497. https://doi.org/10.1371/journal.pone. 0275497.

  2. Al-aamel, A.N.A. and Al-maliky, B.S.A. (2023). Control pepper fusarium wilting by biocontrol agent Trichoderma harzianum and chelated iron Fe-EDDHA. Baghdad Science Journal. 20(6): https://doi.org/10.21123/bsj.2023.8037. 

  3. A Alengebawy, A., Abdelkhalek, S.T., Qureshi, S.R. and Wang, M.Q. (2021). Heavy metals and pesticides toxicity in agricultural soil and plants: Ecological risks and human health implications. Toxics. 9(3): 42. https://doi.org/10.3390/toxics9030042.

  4. Ali, J., Khan, S., Khan, A., Waqas, M. and Nasir, M.J. (2020). Contamination of soil with potentially toxic metals and their bioaccumula- tion in wheat and associated health risk. Environmental Monitoring and Assessment. 192(2): 138. https://doi.org/ 10.1007/s10661-020-8096-6.

  5. Aljanabi, Z.Z., Hassan, F.M. and Al-Obaidy, A.H.M.J. (2022). Heavy metals pollution profiles in Tigris River within Baghdad city’, in IOP Conference Series: Earth and Environmental Science. IOP Publishing. pp. 12008. https://doi.org/10.1088/1755-1315/1088/1/012008. 

  6. Ao, M., Chen, X., Deng, T., Sun, S., Tang, Y., Morel, J.L., Qiu, R. and Wang, S. (2022). Chromium biogeochemical behaviour in soil-plant systems and remediation strategies: A critical review. Journal of Hazardous Materials. 424: 127233. https://doi.org/10.1016/j.jhazmat.2021.127233.

  7. Aslam, M.M., Okal, E.J. and Waseem, M. (2023). Cadmium toxicity impacts plant growth and plant remediation strategies. Plant Growth Regulation. 99(3): 397-412. https://doi.org/ 10.1007/s10725-022-00917-7.

  8. Awad, E.S., Imran, N.S., Albayati, M.M., Snegirev, V., Sabirova, T.M., Tretyakova, N.A., Alsalhy, Q.F., Al-Furaiji, M.H., Salih, I.K. and Majdi, H.S. (2022). Roundwater hydrogeochemical and quality appraisal for agriculture irrigation in greenbelt area, Iraq. Environments. 9(4): 43. https://doi.org/10. 3390/environments9040043. 

  9. Bhardwaj, H., Singh, C. and Nayyar, S. (2022). Assessment of adverse effects of lead, nickel and cadmium on biochemical parameters, antioxidants status and metallothionein expression in buffaloes slaughtered at local abattoir. Indian Journal of Animal Research. 56(2): 145-152. doi: 10.18805/IJAR.B-4242.

  10. Bialkowski, S.E., Astrath, N.G.C. and Proskurnin, M.A. (2019). Photo- thermal Spectroscopy Methods. John Wiley and Sons. 

  11. Blanco, A., Pignata, M.L., Lascano, H.R., Salazar, M.J. and Rodriguez, J.H. (2021). Lead uptake and translocation pathways in soybean seedlings: the role of ion competition and transpiration rates. Environmental Science and Pollution Research. 28: 20624-20636. https://doi.org/10.1007/s11356-020-11901-x.

  12. Castro, A.R., Martins, G., Salvador, A.F. and Cavaleiro, A.J. (2022). Iron compounds in anaerobic degradation of petroleum hydrocarbons: A review. Microorganisms. 10(11): 2142. https://doi.org/10.3390/microorganisms10112142.

  13. Chowdhury, I.R., Chowdhury, S., Mazumder, M.A.J. and Al-Ahmed, A. (2022). Removal of lead ions (Pb2+) from water and wastewater: A review on the low-cost adsorbents. Applied Water Science. 12(8): 185. https://doi.org/10.1007/s13201- 022-01703-6.

  14. Chukhin, V.A. and Andrianov, A.P. (2022). Formation mechanism of iron tubercles during corrosion of water supply pipes. Int. J. Corros. Scale Inhib. 11(2): 812-830. https://doi.org/ 10.1007/s13201-022-01703-6.

  15. Coetzee, J.J., Bansal, N. and Chirwa, E.M.N. (2020). Chromium in environment, its toxic effect from chromite-mining and ferrochrome industries and its possible bioremediation. Exposure and Health. 12: 51-62. https://doi.org/10.1007/ s12403-018-0284-z.

  16. Dey, S., Tripathy, B., Kumar, M.S. and Das, A.P. (2023). Ecotoxicological consequences of manganese mining pollutants and their biological remediation. Environmental Chemistry and Ecotoxicology. 5: 55-61. https://doi.org/10.1016/j.enceco. 2023.01.001.

  17. Dietrich, A.M. and Burlingame, G.A. (2020). A review: the challenge, consensus and confusion of describing odors and tastes in drinking water. Science of the Total Environment. 713: 135061. https://doi.org/10.1016/j.scitotenv.2019.135061.

  18. Dvorak, B.I. and Schuerman, B. (2021). Drinking water: Iron and manganese.

  19. El-Naggar, A., Ahmed, N., Mosa, A., Niazi, N.K., Yousaf, B., Sharma, A., Sarkar, B., Cai, Y. and Chang, S.X. (2021). Nickel in soil and water: Sources, biogeochemistry and remediation using biochar. Journal of Hazardous Materials. 419: 126421. https://doi.org/10.1016/j.jhazmat.2021.126421.

  20. Erikson, K.M. and Aschner, M. (2019). Manganese: Its role in disease and health. Met. Ions Life Sci. 19(1): 253-266.

  21. Fagnano, M., Agrelli, D., Pascale, A., Adamo, P., Fiorentino, N., Rocco, C., Pepe, O. and Ventorino, V. (2020). Copper accumulation in agricultural soils: Risks for the food chain and soil microbial populations. Science of the Total Environment. 734: 139434. https://doi.org/10.1016/j.scitotenv.2020.139434.

  22. GracePavithra, K., Jaikumar, V., Kumar, P.S. and Sundar Rajan, P. (2019). A review on cleaner strategies for chromium industrial wastewater: Present research and future perspective. Journal of Cleaner Production. 228: 580-593. https://doi.org/10.1016/j.jclepro.2019.04.117.

  23. Gundacker, C., Forsthuber, M., Szigeti, T., Kakucs, R., Mustieles, V., Fernandez, M.F., Bengtsen, E., Vogel, U., Hougaard, K.S. and Saber, A.T. (2021). Lead (Pb) and neuro development: A review on exposure and biomarkers of effect (BDNF, HDL) and susceptibility. International Journal of Hygiene and Environmental Health. 238: 113855. https://doi.org/ 10.1016/j.ijheh.2021.113855.

  24. Hayat, M.T., Nauman, M., Nazir, N., Ali, S. and Bangash, N. (2019). Environmental hazards of cadmium: Past, present and future in Cadmium toxicity and tolerance in plants. Elsevier.  pp. 163-183. https://doi.org/10.1016/B978-0-12-814864- 8.00007-3.

  25. Msong, W., Tzudir, L., Longkumer, L.T., Gohain, T. and Kawikhonliu, Z. (2023). Effect of sulphur and zinc fertilization on growth and yield of soybean [Glycine max (L.) Merrill] under Nagaland condition. Agricultural Science Digest. 43(5): 637-642. doi: 10.18805/ag.D-5758.

  26. Khoshru, B., Mitra, D., Nosratabad, A.F., Reyhanitabar, A., Mandal, L., Farda, B., Djebaili, R., Pellegrini, M., Guerra-Sierra, B.E., Senapati, A. and Panneerselvam, P. (2023). Enhancing manganese availability for plants through microbial potential: A sustainable approach for improving soil health and food security. Bacteria. 2(3): 129-141. https://doi. org/10.3390/bacteria2030010.

  27. Kumar, A., Kumar, A., Chaturvedi, A.K., Shabnam, A.A., Subrahmanyam, G., Mondal, R., Gupta, D.K., Malyan, S.K., Kumar, S.S.A. Khan, S. and Yadav, K.K. (2020). Lead toxicity: Health hazards, influence on food chain and sustainable remediation approaches. International Journal of Environmental Research and Public Health. 17(7): 2179. https://doi.org/ 10.3390/ijerph17072179.

  28. Kumar, V., Sharma, A., Kaur, P., Sidhu, G.P.S., Bali, A.S., Bhardwaj, R., Thukral, A.K. and Cerda, A. (2019). Pollution assessment of heavy metals in soils of India and ecological risk assessment: A state-of-the-art. Chemosphere. 216: 449-462. https://doi.org/10.1016/j.chemosphere.2018.10.066.

  29. Kushwaha, A., Hans, N., Kumar, S. and Rani, R. (2018). A critical review on speciation, mobilization and toxicity of lead in soil-microbe-plant system and bioremediation strategies. Ecotoxicology and Environmental Safety. 147: 1035-1045. https://doi.org/10.1016/j.ecoenv.2017.09.049.

  30. Mahdi, A.H., Ahmed, A. and Tobeia, S.B. (2023). Preservation of wastewater sedimentation tanks by using proposed types of coatings. KSCE Journal of Civil Engineering. 27(6): 2586-2592. https://doi.org/10.1007/s12205-023-1963-2.

  31. Masindi, V. and Muedi, K.L. (2018). Environmental contamination by heavy metals. Heavy Metals. 10(4): 115-133. https:/ /dx.doi.org/10.5772/intechopen.76082.

  32. Mishra, S., Bharagava, R.N., More, N., Yadav, A., Zainith, S., Mani, S. and Chowdhary, P. (2018). Heavy metal contamination: An alarming threat to environment and human health’, in Environmental biotechnology: For sustainable future. Springer. pp. 103-125. https://doi.org/10.1007/978-981- 10-7284-0_5.

  33. Mudd, G.M. and Jowitt, S.M. (2022). The new century for nickel resources, reserves and mining: Reassessing the sustainability of the devil’s metal. Economic Geology. 117(8): 1961-1983. https://doi.org/10.5382/econgeo.4950.

  34. Namee, A.M., Bahaa, Z. and Fattah, M.Y. (2023). Some strategies for reducing and/or removing heavy metals from contaminated soil: A review. In AIP Conference Proceedings. AIP Publishing. https://doi.org/10.1063/5.0164242.

  35. Natasha, N., Shahid, M., Bibi, I., Iqbal, J., Khalid, S., Murtaza, B., Bakhat, H.F., Farooq, A.B.U., Amjad, M., Hammad, H.M. and Niazi, N.K. (2022). Zinc in soil-plant-human system: A data-analysis review. Science of the Total Environment. 808: 152024. https://doi.org/10.1016/j.scitotenv.2021. 152024.

  36. Numaan, M.M., Kadhem, A.J., Moyel, M.S., Bayati, M.B., Sabeeh, N.N., Alabdraba, W.M.S., Abbas, A.H., Inniss, E.C. and Fidalgo, M.M. (2024). Study the possibility of using the treated industrial wastewater of north refineries company, Baiji-Iraq, for irrigation purposes. Tikrit Journal of Engineering Sciences. 31(4): 183-190. https://doi.org/10.25130/ tjes.31.4.18.

  37. Onakpa, M.M., Njan, A.A. and Kalu, O.C. (2018). A review of heavy metal contamination of food crops in Nigeria. Annals of Global Health. 84(3): 488. https://doi.org/10.29024/aogh. 2314.

  38. Rashid, A., Schutte, B.J., Ulery, A., Deyholos, M.K., Sanogo, S., Lehnhoff, E.A. and Beck, L. (2023). Heavy metal contamination in agricultural soil: Environmental pollutants affecting crop health. Agronomy. 13(6): 1521. https://doi.org/10.3390/ agronomy13061521.

  39. Rengel, Z. (2015). Availability of Mn, Zn and Fe in the rhizosphere. Journal of Soil Science and Plant Nutrition. 15(2): 397-409. http://dx.doi.org/10.4067/S0718-95162015005000036.

  40. Santos, C.S., Ozgur, R., Uzilday, B., Turkan, I., Roriz, M., Rangel, A.O., Carvalho, S.M. and Vasconcelos, M.W. (2019). Understanding the role of the antioxidant system and the tetrapyrrole cycle in iron deficiency chlorosis. Plants. 8(9): 348. https://doi.org/10.3390/plants8090348.

  41. Sawut, R., Kasim, N., Maihemuti, B., Hu, L., Abliz, A., Abdujappar, A. and Kurban, M. (2018). Pollution characteristics and health risk assessment of heavy metals in the vegetable bases of northwest China. Science of the Total Environment. 642: 864-878. https://doi.org/10.1016/j.scitotenv.2018. 06.034.

  42. Shahid, M., Shamshad, S., Rafiq, M., Khalid, S., Bibi, I., Niazi, N.K., Dumat, C. and Rashid, M.I. (2017). Chromium speciation, bioavailability, uptake, toxicity and detoxification in soil- plant system: A review. Chemosphere. 178: 513-533. https://doi.org/10.1016/j.chemosphere.2017.03.074.

  43. Sobri, N.A.M., Harun, N. and Yunus, M.Y.M. (2024). A review of the ion exchange leaching method for extracting rare earth elements from ion adsorption clay. Chemical Engineering Research and Design [Preprint]. https://doi.org/10.1016/ j.cherd.2024.06.023.

  44. Tumolo, M., Ancona, V., De Paola, D., Losacco, D., Campanale, C., Massarelli, C. and Uricchio, V.F., (2020). Chromium pollution in European water, sources, health risk and remediation strategies: An overview. International Journal of Environmental Research and Public Health. 17(15): 5438. https://doi.org/10.3390/ijerph17155438.

  45. Ukaogo, P.O., Ewuzie, U. and Onwuka, C.V. (2020). Environmental pollution: Causes, effects and the remedies’, in Microorganisms for sustainable environment and health. Elsevier. pp. 419-429. https://doi.org/10.1016/B978-0-12-819001- 2.00021-8.

  46. Vyas, V.R. and Shukla, P.J. (2020). Bioremediation of lead using bacterial isolates and study their plant relieving effect on wheat under metal contamination. Bhartiya Krishi Anusandhan Patrika. 35(1 and 2): 51-56. doi: 10.18805/BKAP222.

  47. Wang, L., Xia, X., Zhang, W., Wang, J., Zhu, L., Wang, J., Wei, Z. and Ahmad, Z. (2019). Separate and joint eco-toxicological effects of sulfadimidine and copper on soil microbial biomasses and ammoxidation microorganisms abundances. Chemosphere. 228: 556-564. https://doi.org/10.1016/j.chemosphere.2019.04.165.

  48. Weldeslassie, T., Naz, H., Singh, B. and Oves, M. (2018). Chemical contaminants for soil, air and aquatic ecosystem. Modern Age Environmental Problems and their Remediation. pp. 1-22. https://doi.org/10.1007/978-3-319-64501-8_1.

  49. Wu, X., Cobbina, S.J., Mao, G., Xu, H., Zhang, Z. and Yang, L. (2016). A review of toxicity and mechanisms of individual and mixtures of heavy metals in the environment. Environ- mental Science and Pollution Research. 23: 8244-8259. https://doi.org/10.1007/s11356-016-6333-x.

  50. Yang, Y., Huang, J., Sun, Q., Wang, J., Huang, L., Fu, S., Qin, S., Xie, X., Ge, S., Li, X. and Cheng, Z. (2022). MicroRNAs: Key players in plant response to metal toxicity. International Journal of Molecular Sciences. 23(15): 8642. https://doi. org/10.3390/ijms23158642.

  51. Yin, K., Wang, Y., Zhao, H., Wang, D., Guo, M., Mu, M., Liu, Y., Nie, X., Li, B., Li, J. and Xing, M., (2021). A comparative review of microplastics and nanoplastics: Toxicity hazards on digestive, reproductive and nervous system. Science of the Total Environment. 774: 145758. https://doi.org/10. 1016/j.scitotenv.2021.145758.

  52. Zakaria, Z., Zulkafflee, N.S., Redzuan, N.A.M., Selamat, J., Ismail, M.R., Praveena, S.M., Tóth, G. and Razis, A.F.A. (2021). Understanding potential heavy metal contamination, absorption, translocation and accumulation in rice and human health risks. Plants. 10(6): 1070. https://doi.org/10. 3390/plants10061070.

  53. Zhang, X., Yan, L., Liu, J., Zhang, Z. and Tan, C. (2019). Removal of different kinds of heavy metals by novel PPG-nZVI beads and their application in simulated stormwater infiltration facility. Applied Sciences. 9(20): 4213. https:/ /doi.org/10.3390/app9204213.

  54. Zhen, Y., Ge, L., Chen, Q., Xu, J., Duan, Z., Loor, J.J. and Wang, M. (2022). Latent benefits and toxicity risks transmission chain of high dietary copper along the livestock-environment- plant-human health axis and microbial homeostasis: A review. Journal of Agricultural and Food Chemistry. 70(23): 6943-6962. https://doi.org/10.1021/acs.jafc.2c01367.
Published In
Agricultural Science Digest
Article Metrics
Metrics Icon
0
Views
0
Citations
Reviewed By
Share Article
Download Article
In this Article
    Contact us
    Follow us

    Full Research Article

    Assessment of the Risks of Heavy Metal Contamination in Irrigation Water, Soils and Crops in Agricultural Fields Near Some Oil Fields

    A
    Al-Aamel1
    A
    Ali Nasser1,*
    https://orcid.org/0009-0006-4660-4741
    A
    Al-Taie1
    https://orcid.org/0000-0003-4800-6113
    S
    S.A. Ahmed1
    A
    Ahmed H. Sadeq1
    https://orcid.org/0009-0004-1181-8032
    L
    Lara Basheer Yaser2
    https://orcid.org/0009-0002-1201-0348
    1Environmental Research Center, University of Technology- Iraq, 10066, Baghdad, Iraq.
    2Department Plant Protection, College of Agricultural Engineering Sciences, University of Baghdad, 10071, Baghdad, Iraq.

    ABSTRACT

    Background: The primary objective of the current study is to evaluate the environmental risks and heavy metal contamination in irrigation water, soil and crops cultivated in agricultural fields near certain oil fields.

    Methods: Atomic absorption spectrometry was used to test and analyze water, soil and plant samples for Cadmium (Cd), Chromium (Cr), Lead (Pb), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni) and Zinc (Zn).

    Result: The samples extremely low concentrations of Cd, Cr and Pb were found in the laboratory, indicating that the local environment is free of these heavy metal contaminants. Fe was the dominant pollutant, exhibiting severely high concentrations, soil at the Amara site (BS) contained Fe at 85,369.62 mg/kg, far exceeding the WHO safety limit. Mn also showed significant contamination, with crop levels reaching 821.97 mg/kg, well above recommended guidelines. In contrast, concentrations of Cu (13.21-83.15 mg/kg), Ni (3.44-86.26 mg/kg) and Zn (52.88-174.40 mg/kg) in water, soil and crop samples were found to be within the permissible limits according to international standards. This stark divergence confirms that the multi-element contamination, as identified by the composite index, is primarily driven by Fe and Mn. The significant bioaccumulation of these metals in crops Fe at 645-673 mg/kg versus a 50-300 mg/kg standard, highlights a critical pathway from soil to the food chain. These findings unequivocally point to anthropogenic activities from the oil fields as the source of pollution, posing a direct threat to agricultural safety and potential human health risks. 

    INTRODUCTION

    Heavy metals accumulate in soils, especially metals that are not biodegradable or thermally degradable, which affects the quality of cultivated agricultural soils and pollution levels reach the food chain, This accumulation comes from natural sources or various human activities such as poor drainage of sewage or the presence of oil fields within cities and incorrect methods of waste disposal and excessive use of chemical pesticides to combat pests (Kumar et al., 2019). Many studies have indicated that heavy metals in crops such as Wheat, Rice and vegetables in addition to animals, can spread and accumulate and thus reach the population, causing health problems for humans (Mishra et al., 2018; Ali et al., 2020; Vyas and Shukla, 2020; Zakaria et al., 2021). It has been found that continuous exposure to cadmium (Cd) causes serious problems such as lung cancer, kidney damage and blood pressure disorders (Sawut et al., 2018). There are serious worries that heavy metals could enter the food chain from oil fields due to their close proximity to agricultural fields in some places. The source mostly determines the behavior and distribution of toxic metals, which include lead, chromium and cadmium. These metals can cause developmental abnormalities, organ damage and cancer (Bhardwaj, et al., 2022), High concentrations of Nickel (Ni) in water and soil lead to its reaching the human body through absorption by plants and may lead to health risks such as allergies, lung damage and cancer (El-Naggar et al.,  2021). In addition to being a carcinogenic metal, Lead (Pb) is regarded as a hazardous metal that spreads, builds up and poses health hazards like diabetes, heart problems and stunted growth (Gundacker et al., 2021). (Tumolo et al., 2020) also stated that all living organisms are affected by Chromium (Cr), which poses a risk to human health due to its effects on DNA damage and the development of cancer. Depending on exposure levels, it can cause skin irritation. It is found in groundwater and groundwater, as well as areas near chemical and tanning facilities. Oil extraction and processing are potential anthropogenic sources of a wide range of elements. These include essential elements such as Copper (Cu), Zinc (Zn), Iron (Fe) and Manganese (Mn), which can become hazardous contaminants at elevated concentrations, disrupting soil microbial ecosystems and posing non-carcinogenic health risks such as neurotoxicity and gastrointestinal diseases. The potential of Cu to oxidize and degrade numerous vital enzymes in soil microorganisms makes it dangerous and a high concentration of Cu in the soil can endanger the ecosystem and a variety of creatures that live there. In terms of the diversity and richness of microorganisms, its high concentrations in the soil may be hazardous to the environment and impact soil functioning (Fagnano et al., 2020). For many livings things Fe is a necessary nutrient and a vital element. It is regarded as a secondary contaminant and as its concentration in soil and water rises, it may affect human health by affecting the liver, pancreas, blood cells, stomach issues and nausea. In addition, vegetables with high iron content are ugly and black (Akhtar et al., 2022). In trace amounts Mn a naturally occurring oxidizing and reducing mineral, is a necessary nutrient, elevated concentrations of it in soil and water can enter the food chain and result in non-cancerous health issues like neurotoxicity symptoms in people (Erikson and Aschner, 2019). Zinc (Zn) also plays an important role in stimulating many growth and reproduction enzymes (Imsong et al., 2023), as it is linked to DNA and cell division in moderate quantities, while increasing its concentration leads to poor appetite, diarrhea, vomiting, nausea and headaches and affects the human immune system. Therefore, its concentration should be limited in water and soil suitable for agriculture (Natasha et al., 2022). Consequently, this study provides a comparative environmental risk assessment to determine the concentrations of eight heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in irrigation water, soil and crop samples taken from agricultural fields close to two separate oil fields (Ajil in central Iraq and Amara in the south) and evaluates the results according to international safety standards.
     

    MATERIALS AND METHODS

    Study site
     
    The experiment was conducted in the year 2023-2024, all experimental tests were conducted at the Environmental Research Center, University of Technology, Iraq and two sites were selected to conduct the study. The first is the agricultural fields near the Ajil oil field (A), located in Salah al-Din Governorate in central Iraq, 180 km north of the capital, Baghdad (Latitude 34.50o N, Longitude 43.20o E).  The second is the agricultural fields near the Amara oil field (B), located in Maysan Governorate in southern Iraq, 320 km southeast of the capital, Baghdad (Latitude 31.85o N, Longitude 47.15o E).
     
    Sample collection
     
    Samples were collected from agricultural fields and included: Irrigation water (W), soil (S) and different crops (C), with four replicates for each sample from both locations (A and B). The agricultural fields are approximately 5 km away from the oil fields, separated by an earthen barrier to prevent farmers from using the lands near the oil fields for agricultural purposes (Fig 1). Oil processing operations are accompanied by secondary gases that are burned and released into the atmosphere (Fig 2), causing air pollution in the surrounding areas and it is expected that the cultivated crops will be polluted by it during breathing processes (Ukaogo and Onwuka, 2020), The water used to get rid of the oil salinity in the fields is poured into the surrounding soil without treatment (Fig 3). This poses a long-term danger, as this water, with the heavy element particles it carries, may penetrate the groundwater and reach the soil of the agricultural fields nearby, causing pollution. Consequently, the pollution reaches the cultivated crops and from there to the human consumer (Rashid et al., 2023). Water samples were taken from wells used for irrigation, soil was collected from a depth of 25 cm and crop samples were collected randomly without specifying the crop type, including the entire plant.

    Fig 1: Agricultural fields from which samples were collected.



    Fig 2: Gases associated with oil processing operations.



    Fig 3: The soils adjacent to the oil fields.



    Examination methods
     
    Standard testing methods were used to test the heavy metals of the samples. Water samples were filtered using filter paper and preserved by adding (1 ml) of nitric acid to prepare them for testing, while soil and plant samples were digested by adding a mixture of nitric acid (10 ml) and hydrochloric acid (30 ml) to (0.5 g) of the sample after drying and grinding it, then it was heated at 60°C for two hours (Fig 4), filtered and the volume was completed to (100 ml) with deionized water (Bialkowski and Proskurnin, 2019), Heavy elements (Cd, Ni, Pb, Cr, Cu, Fe, Mn and Zn) were examined at the Environmental Research Center/University of Technology using an Atomic Absorption Spectroscopy AAS 6300 from Shimadzu, Japan, according to the approved standard method 3030 E.

    ​

    Fig 4: Digestion of soil and plant samples.

    RESULTS AND DISCUSSION

    Test results
     
    Tables 1, 2 and 3 show the results of heavy metal tests for the samples used in the study as follows:

    Table 1: Heavy metal test results for water samples*.



    Table 2: Results of heavy metal tests for samples from the Ajil oil field site (A)*.



    Table 3: Results of heavy metal tests for samples from the Amarah oil field site (B)*.


     
    Water samples
     
    The results of the Table 1 indicate that the Ajil site (AW) recorded the highest concentrations, as Fe reached 2526.48 µg/L, followed by Mn: 503.13 µg/L, then Zn: 65.03 µg/L, Ni: 40.48 µg/L and Cu: 17.53 µg/L, while the concentrations of Cd, Cr and Pb were below the detectable limits (0.00 µg/L). The Amara site (BW) recorded the following concentrations: Fe: 15662.80 µg/L, Mn: 471.35 µg/L, Zn: 75.30 µg/L, Ni: 53.70 µg/L, Cu: 17.08 µg/L. Meanwhile, the concentrations of Cd, Cr and Pb were below the detectable limits (0.00 µg/L).
     
    Soil and crop samples
     
    The results of Table 2 showed that the soil samples (AS) at the Ajil site (A) had the highest concentration of Fe: 71859.23 mg/kg, followed by Mn: 942.85 mg/kg, Zn: 72.88 mg/kg, Ni: 17.08 mg/kg and Cu: 10.62 mg/kg. While the concentrations of Cd, Cr and Pb were undetectable (0.00 mg/kg). As for crop samples from the same site, Fe recorded the highest concentration of 673.40 mg/kg, followed by Mn: 759.79 mg/kg, Cu: 16.17 mg/kg, Zn: 56.67 mg/kg and Ni: 3.71 mg/kg. Concen-trations of Cd, Cr and Pb were undetectable (0.00 mg/kg).

    The results of Table 3 showed that the soil samples (BS) at Amarah site (B) recorded the highest concentration of Fe: 85369.62 mg/kg, followed by Zn: 174.40 mg/kg, Ni: 86.26 mg/kg, Cu: 83.15 mg/kg and Mn: 338.56 mg/kg. The concentrations of Cd, Cr and Pb were undetectable (0.00 mg/kg). As for crop samples (BC) from the same site, Mn recorded the highest concentration of 821.97 mg/kg, followed by Fe: 645.41 mg/kg, Zn: 52.88 mg/kg, Cu: 13.21 mg/kg and Ni: 3.44 mg/kg. Concentrations of Cd, Cr and Pb were undetectable (0.00 mg/kg).

    Contrary to expectations, the results indicated that contamination with hazardous elements Cadmium, Chromium and Lead is not present, whether in irrigation water or in soils and cultivated crops. The reason for this is the possible absence of rocks bearing these elements in the studied areas or their absence in the water accompanying production. It may also be due to the distance between agricultural fields and oil fields and the pollutants that accompany them, which was confirmed by Onakpa et al., (2018) and  Awad et al., (2022) were mentioned that keeping agricultural areas away from oil sources could avoid contamination with dangerous metals that could be transferred to food. Several studies have reported that cadmium accumulation in soil and plants typically results from the use of agricultural technology and industrial activities, as well as from sewage sludge, it is also present in soils with low pH (Aslam, et al., 2023). Its direct effect is to inhibit microbial activity and the metabolism of beneficial microorganisms by affecting their respiration, in addition to altering the soil physicochemical properties. It also affects plant physiology by competing with cadmium for the uptake of beneficial plant nutrients (Alengebawy et al., 2021), It also affects plant physiology by competing with cadmium for the uptake of beneficial plant nutrients and The phenotypic effects of cadmium on plants include decreased the size and weight of roots and shoots; cytotoxicity, which results in decreased chlorophyll content and reduced photosynthetic efficiency; and metabolic processes, which include cell damage and chlorosis Hayat et al., (2019).

    Particles of chromium are present in the environment and are released by liquid waste from mining, tanneries, construction, painting, photographing, printing and medical industries, Because it pollutes the environment, it is seen as a serious health risk (GracePavithra et al., 2019), Additional environmental sources of chromium include, liquid fuel-powered power plants, waste from industries and rocks that have been worn by air and water (Shahid et al., 2017), Toxic chromium seeps into water bodies and then onto adjacent fields when industrial waste is released into the soil (Coetzee, et al., 2020), Although chromium contamination isn’t an international problem, local biogeochemical cycles may be affected by high levels of this contaminant due to metal penetration into the soil, water, or atmosphere (Yang et al., 2022), Chromium benefits plants at low concentrations, but at high concentrations, it inhibits growth by affecting seed germination and photosynthesis efficiency. It can also damage root cells, leading to plant death and reduced productivity (Ao et al., 2022).

    Lead is a toxic heavy metal and a major pollutant that poses health risks when present in water, soil and plants, even at low concentrations (Blanco et al., 2021), This element can be found naturally in a variety of forms, such as lead sulfide or complex ores. Acid rain, car emissions, the burning of petroleum and natural gas and wastewater from homes and businesses are some of the industrial processes that discharge its byproducts into the biosphere (Chowdhury et al., 2022; Kumar et al., 2020). Because lead has detrimental and toxic effects on soil biodiversity and microbiota, it is a problem when it accumulates in water and then soil. In cultivated plants, this results in stress through cell dysfunction, which can lead to weak roots, decreased chlorophyll synthesis, slowed seed germination and overall plant weakening. Additionally, it can build up in specific plant sections and make its way into the food chain, impacting public health and human systems and eventually leading to chronic diseases (Kushwaha et al., 2018).

    The positive results in the absence of these elements in the studied areas do not represent concerns from an environmental or health perspective, despite the many studies mentioned above that showed the risk of increased concentrations of the three elements under study, Cadmium, Chromium and Lead. Ongoing research and testing of these components must be done, nevertheless, in the same locations but with different samples and conditions.

    The results of the copper element showed that the proportions were within the limit permitted by the World Health Organization and this is a good indicator from an environmental perspective, as the presence of copper within specific concentrations is required due to its importance for plant and human health. It is a double-edged sword, as an increase in its concentrations may lead to harm to the plant or humans (Zhen et al., 2022; Numaan et al., 2024). Copper sources vary depending on the environment. It increases in areas with industrial activity or near oil fields, as the results of these fields release varying levels of various elements, including copper, into groundwater or soil. These elements are then cumulatively transferred to plants and from there to human consumers (Masindi and Muedi, 2018). Sources of copper in the agricultural sector can be due to fertilizers and pesticides used, or from animal waste, which leads to its accumulation in the soil and subsequent uptake by plants (Zhang et al., 2019), Copper toxicity disrupts the ecosystem when present at higher than normal levels. Its presence in soil is affected by several factors, including pH, as it increases in acidic soils and poses a threat to the effectiveness of soil microorganisms (Namee et al., 2023), which play a positive role in decomposing soil organic matter. Its effect occurs through the destruction of cell membranes and consequently, the breakdown of microbial proteins (Wang et al., 2019). Copper can react with other elements, such as zinc, leading to reduced absorption of these elements compared to their free state. High levels of copper can also produce free hydroxyl radicals, which increase levels of reactive oxygen (ROS) species and thus damage plant cells, potentially leading to plant death and reduced yields (Wu et al., 2016), Considering the positive concentrations of copper shown in the current study, we can say that the studied areas are environmentally safe from this element, but continuous monitoring is necessary to avoid the possibility of its increase in different conditions.

    While iron showed a significant increase in all samples used in the study, with concentrations exceeding the permissible limit, the cause may be oil pollutants, water associated with production and refining process emissions that settle in soil and waterway (Weldeslassie et al., 2018), or it may be due to natural corrosion of fuel pipes and tanks made of iron (Chukhin and Andrianov, 2022; Mahdi et al., 2023), Many studies indicate that the soil near oil fields is rich in iron due to the dissolution of its compounds in groundwater or the effect of the accompanying organic acids that seep into the soil (Castro et al., 2022). Some plants have a high capacity to absorb heavy elements, which explains why iron is high in plants due to its presence in abundant quantities in water and soil (Al-aamel and Al-maliky, 2023). High iron levels in water cause a change in color and taste, contribute to the formation of sediments, or may interact with some compounds, resulting in toxic substances. High iron levels in soil reduce its fertility due to its effect on the pH level and reduce the absorption of other nutrients (Dietrich and Burlingame, 2020; Dvorak and Schuerman, 2021), as for its high levels in plants, it may cause yellowing of leaves, inhibit growth and accumulate in plant tissues, thus reaching the food chain (Santos et al., 2019).

    The results also indicated that the manganese concentration exceeded the permissible limits of international standards. The reason may be the leakage of drilling fluids rich in this element, or associated water, or emissions into the water and subsequently into the soil and then the plants (Sobri et al., 2024), or it may be due to the dissolution of minerals, a decrease in the acidity of the soil, or the use of fertilizers and pesticides containing this element (Dey et al., 2023), This increase leads to the deposition of manganese oxides and has negative effects on beneficial microorganisms, causing an imbalance in the nutritional balance and affecting the low production of cultivated crops (Khoshru et al., 2023), Despite its importance in plant life processes, manganese is required in small quantities. Depending on the availability of manganese, plants must either utilize it efficiently under restricted conditions or detoxify this excess mineral, based on the physicochemical characteristics of the soil, particularly in acidic soils and the redox processes that result in elevated levels of this element, manganese can have a harmful effect on plants when it is present in high concentrations and proportions Rengel, (2015), as for its danger to human health, high concentrations of it lead to problems in the nervous, digestive and reproductive systems (Yin et al., 2021).

    These high levels, which could be dangerous if they accumulate over the long term, require a comprehensive analysis of the studied areas to determine the main causes that lead to the rise of this element in these areas and to take some ongoing measures and treatments to reduce the existing pollution.

    As for the results of the nickel and zinc elements, they showed that indicated levels lower than the internationally permitted limits, which may be due to the scarcity of natural resources in rock formations, low rates of chemical weathering and their lack of use in large quantities in drilling and production operations (Mudd  and Jowitt, 2022; Aljanabi et al., 2022), This indicates the absence of toxicity from these elements and the safety of the water in the studied areas. These positive results reduce the severity of iron and manganese pollution and emphasize the importance of a comprehensive assessment of heavy elements in areas close to oil fields.

    CONCLUSION

    This study evaluated the potential environmental risks resulting from heavy metal contamination of irrigation water, soil and crops grown in agricultural areas adjacent to the Ajil and Amara oil fields in Iraq. The results of the experiment revealed that there was contamination resulting from increased Iron and Manganese levels in all types of samples studied, with concentrations exceeding the permissible limit set by the WHO. This contamination is likely the result of industrial activities resulting from oil operations, leakage of production fluids, or perhaps the corrosion of pipelines or leakage of untreated water used in oil fields. In contrast, the results indicated the absence of contamination with highly toxic elements such as Cadmium, Chromium and Lead, as concentrations below the permissible limits were recorded in all samples studied. This may be attributed to the scarcity of sources from local industries such as tanning and chemical industries, in addition to the efficiency of the barrier separating the oil fields from agricultural areas. Concentrations of Copper, Nickel and Zinc also gave readings within the environmentally safe limits in all samples. The combined contamination of Iron and Manganese demonstrates a direct pathway for these contaminants to enter the food chain, potentially posing health risks to crop consumers, including gastrointestinal diseases and neurotoxicity, particularly when exposed to these elements over extended periods.
     
    Recommendation
     
    Immediately address iron and manganese contamination using soil improvement and bioremediation techniques, monitor and track trends in water, soil and crop contamination in these areas, take strict measures to enforce regulations for the safe disposal of petroleum product and emissions, conduct further studies on the sources of emissions from oil fields and conduct studies of other elements in different agricultural areas to ensure human safety and health.

    ACKNOWLEDGMENT

    We extend our sincere thanks and gratitude to the Environmental Research Center at the University of Technology for the distinguished scientific and technical support it provided to complete this research. All laboratory tests conducted at the center contributed to reliable results that formed a solid scientific basis for this specialized environmental study. This scientific achievement remains the fruit of the joint efforts of the research team and the distinguished Environmental Research Center, confirming the role of academic institutions in serving environmental issues and sustainable development. 
     
    Disclaimers
     
    The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided but do not accept any liability for any direct or indirect losses resulting from the use of this content.

    CONFLICT OF INTEREST

    The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the study’s design, data collection, analysis, decision to publish or manuscript preparation.

    REFERENCES


    1. Akhtar, S., Luqman, M., Farooq Awan, M.U., Saba, I., Khan, Z.I., Ahmad, K., Muneeb, A., Nadeem, M., Batool, A.I., Shahzadi, M. and Memona, H. (2022). Health risk implications of iron in wastewater soil-food crops grown in the vicinity of peri urban areas of the District Sargodha. PloS one. 17(11): e0275497. https://doi.org/10.1371/journal.pone. 0275497.

    2. Al-aamel, A.N.A. and Al-maliky, B.S.A. (2023). Control pepper fusarium wilting by biocontrol agent Trichoderma harzianum and chelated iron Fe-EDDHA. Baghdad Science Journal. 20(6): https://doi.org/10.21123/bsj.2023.8037. 

    3. A Alengebawy, A., Abdelkhalek, S.T., Qureshi, S.R. and Wang, M.Q. (2021). Heavy metals and pesticides toxicity in agricultural soil and plants: Ecological risks and human health implications. Toxics. 9(3): 42. https://doi.org/10.3390/toxics9030042.

    4. Ali, J., Khan, S., Khan, A., Waqas, M. and Nasir, M.J. (2020). Contamination of soil with potentially toxic metals and their bioaccumula- tion in wheat and associated health risk. Environmental Monitoring and Assessment. 192(2): 138. https://doi.org/ 10.1007/s10661-020-8096-6.

    5. Aljanabi, Z.Z., Hassan, F.M. and Al-Obaidy, A.H.M.J. (2022). Heavy metals pollution profiles in Tigris River within Baghdad city’, in IOP Conference Series: Earth and Environmental Science. IOP Publishing. pp. 12008. https://doi.org/10.1088/1755-1315/1088/1/012008. 

    6. Ao, M., Chen, X., Deng, T., Sun, S., Tang, Y., Morel, J.L., Qiu, R. and Wang, S. (2022). Chromium biogeochemical behaviour in soil-plant systems and remediation strategies: A critical review. Journal of Hazardous Materials. 424: 127233. https://doi.org/10.1016/j.jhazmat.2021.127233.

    7. Aslam, M.M., Okal, E.J. and Waseem, M. (2023). Cadmium toxicity impacts plant growth and plant remediation strategies. Plant Growth Regulation. 99(3): 397-412. https://doi.org/ 10.1007/s10725-022-00917-7.

    8. Awad, E.S., Imran, N.S., Albayati, M.M., Snegirev, V., Sabirova, T.M., Tretyakova, N.A., Alsalhy, Q.F., Al-Furaiji, M.H., Salih, I.K. and Majdi, H.S. (2022). Roundwater hydrogeochemical and quality appraisal for agriculture irrigation in greenbelt area, Iraq. Environments. 9(4): 43. https://doi.org/10. 3390/environments9040043. 

    9. Bhardwaj, H., Singh, C. and Nayyar, S. (2022). Assessment of adverse effects of lead, nickel and cadmium on biochemical parameters, antioxidants status and metallothionein expression in buffaloes slaughtered at local abattoir. Indian Journal of Animal Research. 56(2): 145-152. doi: 10.18805/IJAR.B-4242.

    10. Bialkowski, S.E., Astrath, N.G.C. and Proskurnin, M.A. (2019). Photo- thermal Spectroscopy Methods. John Wiley and Sons. 

    11. Blanco, A., Pignata, M.L., Lascano, H.R., Salazar, M.J. and Rodriguez, J.H. (2021). Lead uptake and translocation pathways in soybean seedlings: the role of ion competition and transpiration rates. Environmental Science and Pollution Research. 28: 20624-20636. https://doi.org/10.1007/s11356-020-11901-x.

    12. Castro, A.R., Martins, G., Salvador, A.F. and Cavaleiro, A.J. (2022). Iron compounds in anaerobic degradation of petroleum hydrocarbons: A review. Microorganisms. 10(11): 2142. https://doi.org/10.3390/microorganisms10112142.

    13. Chowdhury, I.R., Chowdhury, S., Mazumder, M.A.J. and Al-Ahmed, A. (2022). Removal of lead ions (Pb2+) from water and wastewater: A review on the low-cost adsorbents. Applied Water Science. 12(8): 185. https://doi.org/10.1007/s13201- 022-01703-6.

    14. Chukhin, V.A. and Andrianov, A.P. (2022). Formation mechanism of iron tubercles during corrosion of water supply pipes. Int. J. Corros. Scale Inhib. 11(2): 812-830. https://doi.org/ 10.1007/s13201-022-01703-6.

    15. Coetzee, J.J., Bansal, N. and Chirwa, E.M.N. (2020). Chromium in environment, its toxic effect from chromite-mining and ferrochrome industries and its possible bioremediation. Exposure and Health. 12: 51-62. https://doi.org/10.1007/ s12403-018-0284-z.

    16. Dey, S., Tripathy, B., Kumar, M.S. and Das, A.P. (2023). Ecotoxicological consequences of manganese mining pollutants and their biological remediation. Environmental Chemistry and Ecotoxicology. 5: 55-61. https://doi.org/10.1016/j.enceco. 2023.01.001.

    17. Dietrich, A.M. and Burlingame, G.A. (2020). A review: the challenge, consensus and confusion of describing odors and tastes in drinking water. Science of the Total Environment. 713: 135061. https://doi.org/10.1016/j.scitotenv.2019.135061.

    18. Dvorak, B.I. and Schuerman, B. (2021). Drinking water: Iron and manganese.

    19. El-Naggar, A., Ahmed, N., Mosa, A., Niazi, N.K., Yousaf, B., Sharma, A., Sarkar, B., Cai, Y. and Chang, S.X. (2021). Nickel in soil and water: Sources, biogeochemistry and remediation using biochar. Journal of Hazardous Materials. 419: 126421. https://doi.org/10.1016/j.jhazmat.2021.126421.

    20. Erikson, K.M. and Aschner, M. (2019). Manganese: Its role in disease and health. Met. Ions Life Sci. 19(1): 253-266.

    21. Fagnano, M., Agrelli, D., Pascale, A., Adamo, P., Fiorentino, N., Rocco, C., Pepe, O. and Ventorino, V. (2020). Copper accumulation in agricultural soils: Risks for the food chain and soil microbial populations. Science of the Total Environment. 734: 139434. https://doi.org/10.1016/j.scitotenv.2020.139434.

    22. GracePavithra, K., Jaikumar, V., Kumar, P.S. and Sundar Rajan, P. (2019). A review on cleaner strategies for chromium industrial wastewater: Present research and future perspective. Journal of Cleaner Production. 228: 580-593. https://doi.org/10.1016/j.jclepro.2019.04.117.

    23. Gundacker, C., Forsthuber, M., Szigeti, T., Kakucs, R., Mustieles, V., Fernandez, M.F., Bengtsen, E., Vogel, U., Hougaard, K.S. and Saber, A.T. (2021). Lead (Pb) and neuro development: A review on exposure and biomarkers of effect (BDNF, HDL) and susceptibility. International Journal of Hygiene and Environmental Health. 238: 113855. https://doi.org/ 10.1016/j.ijheh.2021.113855.

    24. Hayat, M.T., Nauman, M., Nazir, N., Ali, S. and Bangash, N. (2019). Environmental hazards of cadmium: Past, present and future in Cadmium toxicity and tolerance in plants. Elsevier.  pp. 163-183. https://doi.org/10.1016/B978-0-12-814864- 8.00007-3.

    25. Msong, W., Tzudir, L., Longkumer, L.T., Gohain, T. and Kawikhonliu, Z. (2023). Effect of sulphur and zinc fertilization on growth and yield of soybean [Glycine max (L.) Merrill] under Nagaland condition. Agricultural Science Digest. 43(5): 637-642. doi: 10.18805/ag.D-5758.

    26. Khoshru, B., Mitra, D., Nosratabad, A.F., Reyhanitabar, A., Mandal, L., Farda, B., Djebaili, R., Pellegrini, M., Guerra-Sierra, B.E., Senapati, A. and Panneerselvam, P. (2023). Enhancing manganese availability for plants through microbial potential: A sustainable approach for improving soil health and food security. Bacteria. 2(3): 129-141. https://doi. org/10.3390/bacteria2030010.

    27. Kumar, A., Kumar, A., Chaturvedi, A.K., Shabnam, A.A., Subrahmanyam, G., Mondal, R., Gupta, D.K., Malyan, S.K., Kumar, S.S.A. Khan, S. and Yadav, K.K. (2020). Lead toxicity: Health hazards, influence on food chain and sustainable remediation approaches. International Journal of Environmental Research and Public Health. 17(7): 2179. https://doi.org/ 10.3390/ijerph17072179.

    28. Kumar, V., Sharma, A., Kaur, P., Sidhu, G.P.S., Bali, A.S., Bhardwaj, R., Thukral, A.K. and Cerda, A. (2019). Pollution assessment of heavy metals in soils of India and ecological risk assessment: A state-of-the-art. Chemosphere. 216: 449-462. https://doi.org/10.1016/j.chemosphere.2018.10.066.

    29. Kushwaha, A., Hans, N., Kumar, S. and Rani, R. (2018). A critical review on speciation, mobilization and toxicity of lead in soil-microbe-plant system and bioremediation strategies. Ecotoxicology and Environmental Safety. 147: 1035-1045. https://doi.org/10.1016/j.ecoenv.2017.09.049.

    30. Mahdi, A.H., Ahmed, A. and Tobeia, S.B. (2023). Preservation of wastewater sedimentation tanks by using proposed types of coatings. KSCE Journal of Civil Engineering. 27(6): 2586-2592. https://doi.org/10.1007/s12205-023-1963-2.

    31. Masindi, V. and Muedi, K.L. (2018). Environmental contamination by heavy metals. Heavy Metals. 10(4): 115-133. https:/ /dx.doi.org/10.5772/intechopen.76082.

    32. Mishra, S., Bharagava, R.N., More, N., Yadav, A., Zainith, S., Mani, S. and Chowdhary, P. (2018). Heavy metal contamination: An alarming threat to environment and human health’, in Environmental biotechnology: For sustainable future. Springer. pp. 103-125. https://doi.org/10.1007/978-981- 10-7284-0_5.

    33. Mudd, G.M. and Jowitt, S.M. (2022). The new century for nickel resources, reserves and mining: Reassessing the sustainability of the devil’s metal. Economic Geology. 117(8): 1961-1983. https://doi.org/10.5382/econgeo.4950.

    34. Namee, A.M., Bahaa, Z. and Fattah, M.Y. (2023). Some strategies for reducing and/or removing heavy metals from contaminated soil: A review. In AIP Conference Proceedings. AIP Publishing. https://doi.org/10.1063/5.0164242.

    35. Natasha, N., Shahid, M., Bibi, I., Iqbal, J., Khalid, S., Murtaza, B., Bakhat, H.F., Farooq, A.B.U., Amjad, M., Hammad, H.M. and Niazi, N.K. (2022). Zinc in soil-plant-human system: A data-analysis review. Science of the Total Environment. 808: 152024. https://doi.org/10.1016/j.scitotenv.2021. 152024.

    36. Numaan, M.M., Kadhem, A.J., Moyel, M.S., Bayati, M.B., Sabeeh, N.N., Alabdraba, W.M.S., Abbas, A.H., Inniss, E.C. and Fidalgo, M.M. (2024). Study the possibility of using the treated industrial wastewater of north refineries company, Baiji-Iraq, for irrigation purposes. Tikrit Journal of Engineering Sciences. 31(4): 183-190. https://doi.org/10.25130/ tjes.31.4.18.

    37. Onakpa, M.M., Njan, A.A. and Kalu, O.C. (2018). A review of heavy metal contamination of food crops in Nigeria. Annals of Global Health. 84(3): 488. https://doi.org/10.29024/aogh. 2314.

    38. Rashid, A., Schutte, B.J., Ulery, A., Deyholos, M.K., Sanogo, S., Lehnhoff, E.A. and Beck, L. (2023). Heavy metal contamination in agricultural soil: Environmental pollutants affecting crop health. Agronomy. 13(6): 1521. https://doi.org/10.3390/ agronomy13061521.

    39. Rengel, Z. (2015). Availability of Mn, Zn and Fe in the rhizosphere. Journal of Soil Science and Plant Nutrition. 15(2): 397-409. http://dx.doi.org/10.4067/S0718-95162015005000036.

    40. Santos, C.S., Ozgur, R., Uzilday, B., Turkan, I., Roriz, M., Rangel, A.O., Carvalho, S.M. and Vasconcelos, M.W. (2019). Understanding the role of the antioxidant system and the tetrapyrrole cycle in iron deficiency chlorosis. Plants. 8(9): 348. https://doi.org/10.3390/plants8090348.

    41. Sawut, R., Kasim, N., Maihemuti, B., Hu, L., Abliz, A., Abdujappar, A. and Kurban, M. (2018). Pollution characteristics and health risk assessment of heavy metals in the vegetable bases of northwest China. Science of the Total Environment. 642: 864-878. https://doi.org/10.1016/j.scitotenv.2018. 06.034.

    42. Shahid, M., Shamshad, S., Rafiq, M., Khalid, S., Bibi, I., Niazi, N.K., Dumat, C. and Rashid, M.I. (2017). Chromium speciation, bioavailability, uptake, toxicity and detoxification in soil- plant system: A review. Chemosphere. 178: 513-533. https://doi.org/10.1016/j.chemosphere.2017.03.074.

    43. Sobri, N.A.M., Harun, N. and Yunus, M.Y.M. (2024). A review of the ion exchange leaching method for extracting rare earth elements from ion adsorption clay. Chemical Engineering Research and Design [Preprint]. https://doi.org/10.1016/ j.cherd.2024.06.023.

    44. Tumolo, M., Ancona, V., De Paola, D., Losacco, D., Campanale, C., Massarelli, C. and Uricchio, V.F., (2020). Chromium pollution in European water, sources, health risk and remediation strategies: An overview. International Journal of Environmental Research and Public Health. 17(15): 5438. https://doi.org/10.3390/ijerph17155438.

    45. Ukaogo, P.O., Ewuzie, U. and Onwuka, C.V. (2020). Environmental pollution: Causes, effects and the remedies’, in Microorganisms for sustainable environment and health. Elsevier. pp. 419-429. https://doi.org/10.1016/B978-0-12-819001- 2.00021-8.

    46. Vyas, V.R. and Shukla, P.J. (2020). Bioremediation of lead using bacterial isolates and study their plant relieving effect on wheat under metal contamination. Bhartiya Krishi Anusandhan Patrika. 35(1 and 2): 51-56. doi: 10.18805/BKAP222.

    47. Wang, L., Xia, X., Zhang, W., Wang, J., Zhu, L., Wang, J., Wei, Z. and Ahmad, Z. (2019). Separate and joint eco-toxicological effects of sulfadimidine and copper on soil microbial biomasses and ammoxidation microorganisms abundances. Chemosphere. 228: 556-564. https://doi.org/10.1016/j.chemosphere.2019.04.165.

    48. Weldeslassie, T., Naz, H., Singh, B. and Oves, M. (2018). Chemical contaminants for soil, air and aquatic ecosystem. Modern Age Environmental Problems and their Remediation. pp. 1-22. https://doi.org/10.1007/978-3-319-64501-8_1.

    49. Wu, X., Cobbina, S.J., Mao, G., Xu, H., Zhang, Z. and Yang, L. (2016). A review of toxicity and mechanisms of individual and mixtures of heavy metals in the environment. Environ- mental Science and Pollution Research. 23: 8244-8259. https://doi.org/10.1007/s11356-016-6333-x.

    50. Yang, Y., Huang, J., Sun, Q., Wang, J., Huang, L., Fu, S., Qin, S., Xie, X., Ge, S., Li, X. and Cheng, Z. (2022). MicroRNAs: Key players in plant response to metal toxicity. International Journal of Molecular Sciences. 23(15): 8642. https://doi. org/10.3390/ijms23158642.

    51. Yin, K., Wang, Y., Zhao, H., Wang, D., Guo, M., Mu, M., Liu, Y., Nie, X., Li, B., Li, J. and Xing, M., (2021). A comparative review of microplastics and nanoplastics: Toxicity hazards on digestive, reproductive and nervous system. Science of the Total Environment. 774: 145758. https://doi.org/10. 1016/j.scitotenv.2021.145758.

    52. Zakaria, Z., Zulkafflee, N.S., Redzuan, N.A.M., Selamat, J., Ismail, M.R., Praveena, S.M., Tóth, G. and Razis, A.F.A. (2021). Understanding potential heavy metal contamination, absorption, translocation and accumulation in rice and human health risks. Plants. 10(6): 1070. https://doi.org/10. 3390/plants10061070.

    53. Zhang, X., Yan, L., Liu, J., Zhang, Z. and Tan, C. (2019). Removal of different kinds of heavy metals by novel PPG-nZVI beads and their application in simulated stormwater infiltration facility. Applied Sciences. 9(20): 4213. https:/ /doi.org/10.3390/app9204213.

    54. Zhen, Y., Ge, L., Chen, Q., Xu, J., Duan, Z., Loor, J.J. and Wang, M. (2022). Latent benefits and toxicity risks transmission chain of high dietary copper along the livestock-environment- plant-human health axis and microbial homeostasis: A review. Journal of Agricultural and Food Chemistry. 70(23): 6943-6962. https://doi.org/10.1021/acs.jafc.2c01367.
    In this Article
      Contact us
      Follow us
      Published In
      Agricultural Science Digest

      Editorial Board

      View all (0)