Current IssueEditorial BoardOnline First ArticlesArchive
Current IssueEditorial BoardOnline First ArticlesArchive

Full Research Article

Estimation of Nitrate Contents in Sixteen Varieties of Libyan Dates (Phoenix dactylifera L.) and Their Potential Health Risks

M
Mansour Awiadat Salem1
http://orcid.org/0000-0002-2990-9045
A
Aisha Abdulgader Alshanoky2
http://orcid.org/0009-0008-4575-9084
M
Masouda Mohamed Alshatory1
http://orcid.org/0009-0001-7391-5290
S
Samera Musa Alwaleed2
http://orcid.org/0009-0006-6474-6372
S
Saeda Maatoq Ali Mohamed3
http://orcid.org/0009-0002-3916-6078
S
Saeda Maatoq Ali Mohamed4
http://orcid.org/0000-0002-9675-8304
1Department of Environmental Sciences, Faculty of Environment and Natural Resources, Wadi Alshatti University. Brack, Libya.
2Department of Chemistry, Faculty of Sciences, Wadi Alshatti University. Brack, Libya.
3Department of Zoology, Faculty of Sciences, Sebha University. Sebha, Libya.
4Department of Mechanical and Renewable Energy Engineering, Faculty of Engineering, Wadi Alshatti University, Wadi Alshatti, Libya.

ABSTRACT

Background: Dates play an essential role in the Libyan diet, particularly during Ramadan. As a result, there is considerable emphasis on ensuring that these dates are free from contaminants, especially nitrates, which are prevalent pollutants in food items. Therefore, this study aimed to evaluate the nitrate contents and the potential health risks associated with their consumption by adults and teenagers in various date varieties commonly consumed in Libya.

Methods: A total of sixteen date varieties, mainly gathered from southern Libya, were tested. The findings reveal that the average nitrate content in the date samples ranged between 498.66±135.35 mg/kg in the Tafsert variety and 1147.02±287.97 mg/kg in the Tagayat variety. To determine the potential health risks and safety of these dates, we assessed the Estimated Daily Intake (EDI), Acceptable Daily Intake (ADI) and Hazard Quotient (HQ).

Result: The results indicate that the EDI, ADI and HQ values remained below the thresholds established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The EDI for nitrates was observed to range from 0.34 to 0.77 mg/kg body weight (bw)/day for adults and from 0.45 to 1.04 mg/kg bw/day for teenagers, while the acceptable limit is defined at 3.70 mg/kg bw/day. However, the findings also suggest that teenagers are more susceptible to nitrate levels in dates than adults. Therefore, the amount of dates consumed does not represent a risk to consumers. Additionally, the calculated HQ values for adults and teenagers varied from 0.21 to 0.48 and from 0.28 to 0.65, respectively. Since these HQ values are below 1, they indicate a low level of health risk for consumers.

INTRODUCTION

There are approximately 5,000 varieties of date palms worldwide, with 160 million palms cultivated in the Arab region, yielding about 6.6 million tons annually, which accounts for over 77% of global date production (Hammami et al., 2024). Dates are nutritious fruits that are rich in essential vitamins, minerals, dietary fiber and antioxidants. They promote heart health, aid in digestion and help reduce oxidative stress and inflammation. Dates provide important nutrients, including carbohydrates, proteins, fats, vitamins A and C and minerals such as calcium, iron and magnesium (Shahdadi et al., 2015). Most human nitrate exposure comes from plant-based foods, especially vegetables and certain fruits, accounting for 80% to 95% of daily intake (Pardo-Marín  et al., 2010; Quijano et al., 2017; Qasemi et al., 2024). Dates also contain antioxidants that may inhibit cancer-causing agents, influencing some countries to relax regulations on vegetable nitrate levels (Jannat et al., 2022). Low levels of nitrate are generally considered safe, with the Joint Expert Committee on Food and Agriculture (JECFA) recommending an acceptable daily intake (ADI) of 0-3.7 mg per kilogram of body weight (Hmeljak and Cencič (2013). The type of nitrogen significantly affects plant growth, with primary forms including ammonium (NH4+), nitrate (NO3-) and urea. Different plant species exhibit preferences for these sources, influenced by factors such as nitrogen levels and soil properties (Dong et al., 2018; Al-Ethawi and Salem, 2019). The overuse of chemical fertilizers leads to issues such as soil acidification and groundwater contamination (Salem et al., 2020; Fashaho et al., 2020). Reports indicate alarming levels of heavy metals and nitrates in crops, often due to the irrigation with partially treated sewage water and excessive fertilizer application (Al-Busaidi  et al., 2015; Salehzadeh et al., 2020; Jalali et al., 2021), raising concerns about food safety (El-Nahhal, 2018; Abd-Elrahman  et al., 2022). High nitrate levels can be converted into harmful compounds, such as nitrosamines, while nitrite production can interfere with oxygen transport in the blood (Mensinga et al., 2023; Bolaji et al., 2025). Interestingly, nitrates and nitrites may lower blood pressure in healthy women (Ashworth et al., 2015). Date palms, a key fruit crop in arid regions like Libya, contribute significantly to local economies and are cultivated in over 400 varieties (Racchi and Camussi, 2018). Despite extensive research on heavy metal and nitrate contamination in food, there is a limited number of studies on nitrates in palm dates. This study aims to examine the nitrate content in the studied dates and assess the potential health risks associated with their consumption.

MATERIALS AND METHODS

Study area and sample collection
 
The cultivation of date palms (Phoenix dactylifera L.) has grown significantly in Libya, with an estimated four million trees, mainly in the southern Saharan region (Racchi et al., 2014). Ripe dates are harvested by the end of October. In November 2024, samples of sixteen local date varieties, Degla, Asapeer, Tafsert, Taleas, Awrayag, Aglyen, Ammrayer, Saeyde, Adawy, Sallalow, Akdayer, Tagayat, Apil, Kadray, Majdool and Ajwa, were purchased from the market and brought to the laboratory for analysis.
 
Preparation of palm date samples
 
Date palm samples were prepared following the methods of Ajebe and Bahiru (2019) and Zhao and Wang (2017). One hundred grams of each variety were washed, pitted and cut into uniform pieces, then dried in an oven at 105°C for 24 hours. After cooling, the samples were ground and sieved through a 2 mm mesh. Finally, 4.0 grams of each sample were stored in clean plastic bottles for analysis.
 
Extraction and determination of nitrate in dates
 
Nitrate extraction was performed as per Lufei and Yong (2017). A 0.1 g date sample was suspended in 10 mL distilled water, heated to 80oC for 1 hour, cooled and filtered through Whatman filter paper No. 4. For nitrate determination, 0.1 mL of the extract was mixed with 0.4 mL salicylic acid solution in a 30 mL tube, allowed to sit for 20 minutes and then 9.5 mL of 2 N NaOH was added. The nitrate concentration was measured immediately using a Jenway 7205 spectrophotometer, following Equation (1).
 
 
  
Where,
Y = Nitrate content (mg/kg dwt).
C = Nitrate concentration from OD410 (abs * slope - intercept) using the calibration curve.
V = Total volume of extracted sample (ml).
W = Weight of sample (g).
 
Health risk assessment
 
A study evaluated the health risks associated with date consumption in adults and teenagers, focusing on nitrate levels in various date varieties. The average daily intake was estimated at 110 g for adults and 70 g for teenagers. The estimated daily intake (EDI), percentage of acceptable daily intake (%ADI) and hazard quotient (HQ) were calculated as per Ram et al., (2022).
 
Estimated daily intake (EDI)
 
People can be exposed to pollutants through ingestion, skin contact and inhalation; however, for nitrates, the primary exposure route is oral intake (Qasemi et al., 2024). Excessive nitrate consumption from palm dates can pose health risks if it exceeds the Acceptable Daily Intake (ADI) of 3.7 mg per kilogram of body weight, as set by the European Food Safety Authority (EFSA, 2008). Adults consume about 110 g, while teenagers consume around 70 g of palm dates daily. High nitrate intake can lead to serious health problems or fatalities (Dezhangah et al., 2022). We calculated the average daily nitrate intake based on body weight and bioavailability using the Estimated Daily Intake (EDI) equation, which reflects potential ingestion but does not consider metabolic excretion (USEPA, 2004).
 
  
  
Where:
EDI = Estimated daily intake (mg/kg bw/day).
EF = Exposure frequency (365 days/year).
ED = The exposure duration, which is 70 years for adults and 50 years for teenagers. For teens (7-17 years), the maximum exposure duration is 11 years, while adults over 70 can have a maximum of 30 years (EPA, 1989).
DC indicates daily date consumption: ~110 g/day for Libyan adults (70 kg) and ~70 g/day for teenagers (50 kg), potentially doubling during Ramadan.
MC = Mean nitrate concentration in samples (mg/kg dry weight). BW is the body weight of adult consumers (70 kg) and teenagers (50 kg) (Radfard et al., 2018).
AT = Average Time: 25,550 days for adults and 18,250 days for children (Saha and Zaman, 2013).
 
Noncarcinogenic hazard quotient (NHQ)
 
Human health risk assessment, as defined by the U.S. Environmental Protection Agency (USEPA, 2004), estimates the likelihood of adverse health effects from chemical exposure in contaminated environments. This study conducted a quantitative risk assessment of nitrate exposure from date consumption, utilizing data from the USEPA (2020). The reference dose (RfD) for nitrate is 1.60 mg/kg body weight per day (Gruszecka-Kosowska and Baran, 2017). The Hazard Quotient (HQ) compares individual exposure to the RfD: an HQ > 1 indicates a significant health risk, while HQ < 1 suggests safe exposure levels (Djahed et al., 2018).
 
Statistical analysis
 
All experiments were conducted in triplicate and SPSS version 26 was employed to calculate the minimum, maximum, mean and standard deviation of nitrate levels for the dates under study. The Pearson correlation coefficient (r) was utilized to assess the linear relationships among the various data varieties. The tested date varieties were categorized based on their nitrate content using Ward’s hierarchical clustering analysis. A one-way analysis of variance (ANOVA) was performed to compare the mean nitrate concentrations across the different date varieties. The threshold for statistical significance was set at p<0.05 (Dezhangah et al., 2022).
 
Validation method
 
The validation method focused on data types, permissible limits and process performance characteristics, including precision, accuracy, calibration data and the linearity of the calibration curve (Dezhangah et al., 2022). A linear calibration curve was established using nitrate standards from 10 to 120 mg/L, with three replicates per concentration. Deionized water served as a blank sample to determine the Limits of Quantitation  (LOQ) and Limits of Detection (LOD) (Mehri et al., 2019).

RESULTS AND DISCUSSION

Calibration curve and validation method
 
The calibration equation, which links the analyte to nitrate concentration, was used to determine the nitrate content in palm dates. A calibration curve (Fig 1) was created by measuring seven concentrations of NO3, ranging from 0.0 to 120 mg/L, with samples exceeding this range diluted for reassessment. A multiple linear regression model showed a strong correlation coefficient (R2) of 0.9953. The limits of detection and quantification for NO3- were 6.670 mg/kg and 20.211 mg/kg, respectively. Comparable results were reported by Pardo-Marín  et al. (2010) with a LOD of 7 mg/kg and a LOQ of 20 mg/kg and by Chung et al., (2011) with a LOD of 4 mg/kg and a LOQ of 20 mg/kg.

Fig 1: Nitrate standard curve.


 
Nitrate content in palm dates
 
Table 1 shows the nitrate content of various palm date varieties from Brack City’s local market. The mean nitrate levels (mean ± SD in mg/kg dwt) were as follows: Degla (735.38±464.67), Asapeer (1012.31±277.69), Tafsert (498.65±135.35), Tales (711.27±173.94), Awrayag (637.48±295.77), Aglyen (708.62±218.36), Ammrayer (695.87±69.78), Saeyde (734.52±288.90), Adawy (500.26±56.41), Sallalow (712.43±198.29), Akdayer (676.27±112.36), Tagayat (1085.65±335.46), Apil (798.53±378.75), Kadray (627.73±6.12), Majdool (758.63±198.25) and Ajwa (812.53±38.9). Tafsert exhibited the lowest nitrate content, whereas Tagayat had the highest. The reduced nitrate levels in Tafsert are likely due to cultivation in an oasis without irrigation or fertilisers. Additionally, soil properties and cultivation practices significantly influence nitrate content (Alakhdhari et al., 2025; Kaur et al., 2025). The nitrate levels in our samples are moderate (500-1000 mg/kg), according to Hmeljak and Cenciè (2013). Although permissible limits for dates are not specified in the literature, we reference recommendations from Sayed and Rezvan (2014).

Table 1: Descriptive analysis of Conc. of Nitrate in palm dates varieties (local name) (mg/kg. dwt).


 
Health risk assessment
 
Estimated daily intakes of nitrate
 
Some individuals consume palm dates daily, while others do so occasionally; this study focuses on individuals who consume them daily. The estimated daily nitrate intakes (EDI) for adults (70 kg) and teenagers (50 kg) are outlined in Table 2, showing higher nitrate levels in teenagers. Daily consumption was estimated at 110 g for adults and 70 g for teenagers, with nitrate exposure varying from 132.92 to 305.87 mg/day for adults and 95.63 to 219.97 mg/day for teenagers. The acceptable daily intake of nitrate is 0-3.7 mg/kg body weight/day (Luetic et al., 2023), equating to 259 mg for adults and 185 mg for teenagers. Although Asapeer and Tagayat have high nitrate levels (1012.31 and 1147.0 mg/kg), they remain within JECFA’s recommended limits.

Table 2: Estimated daily intake, mean nitrate intake and Hazards quotient of nitrate from consumption dates varieties.


 
Acceptable daily intake (ADI)
 
Nitrate toxicity can arise from the daily consumption of foods like dates. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has set an acceptable daily intake (ADI) for nitrates at 3.70 mg/kg body weight per day (EFSA, 2008). The %ADI from date consumption for adults and teenagers ranges from 9.08 - 12.21 and 20.88 - 28.08 for Tafsert and Tagayat, respectively. Mean nitrate intake for adults is 0.71 to 1.64 mg/kg/d and for teenagers, it is 1.0 to 2.29 mg/kg/d. Both are within the acceptable limit. Higher ADI values have been observed in some fruits and vegetables in Iran, Bangladesh and Egypt due to high EDI (Mehri et al., 2019; Sebaei and Refai, 2019; Uddin et al., 2021; Zendehbad et al., 2022).
 
Noncarcinogenic risk
 
Several factors influence health risks associated with nitrates, including consumption frequency, inherent risk and individual body weight (Mehri et al., 2019; Ali et al., 2021). Our findings indicate that the Hazard Quotient (HQ) values for all date samples were below 1, suggesting no noncarcinogenic risks associated with date consumption. Specifically, HQ values for nitrates ranged from 0.21 in Tafsert to 0.46 in Tagayat for adults consuming 110 g/day and from 0.28 to 0.65 for teenagers consuming about 70 g/day. The risk from nitrates may vary based on date type, environmental factors, farming practices and storage conditions (Ghasemidehkordi et al., 2018). Notably, teenagers show higher HQ values than adults, indicating they are more vulnerable to nitrate concentrations in dates. Our results align with findings from Mehri et al., (2019), Ali et al., (2021) and Qasemi et al., (2024).
 
Statistical analysis
 
The Pearson correlation coefficient demonstrated a strong association between specific date varieties and their nitrate concentrations, highlighting significant relationships among several of these varieties. These findings will enhance the management of polluted dates, ultimately helping to mitigate the risks they pose to consumers. (Khan et al., 2021). Table 3 depicts Pearson’s correlation matrix for nitrate accumulation in the sixteen varieties of dates (Shown in bold). The results show a strong positive correlation between Deagla and Aurag (r = 0.798), Asaper and Selalew (r = 1.000), Tafsert and Saedi (r = 0.793), Talesh and Tagayat (r = 0.921), Aurag and Saedi (r = 0.872), Agder and Kadray (r =1.000) and Tagayat and Apel (r = 0.994). A positive correlation was observed between Asaper and Aurag (r = 0.852), Tafsert and Aurag (r = 0.581) and Talesh and Apel (r = 0.885). Whereas, strong negative correlations were observed between Deagla and Tagayat (r =- 0.948) and between Asaper and Tagayat (r = -0.923), respectively and between Deagla and Apel (r =- 0.946) and between Asaper and Apel (r = -0.947), respectively. Talesh, Aurag and Saedi (r = -0.895, r = -0.944) respectively. Saedi, Tagayat and Apel (r = -0.970, r = -0.962) respectively. Negative correlation observed only between Tafsert, Tagayat and Apel (r = -0.909, r = -0.899, respectively). Aurag, Tagayat and Apel (r = -0.903, r = -0.891). Fig 2 illustrates the hierarchical clustering of nitrate accumulation in dates, revealing three distinct clusters. The first cluster includes Tagayat and Apel. The second cluster comprises Aurag, Tafsert, Saedi, Deegla, Adwai and Asaper. The third cluster consists of Majdawal, Agdar, Salalew, Amrear, Kadray, Aglen, Ajwa and Talesh (Bahadoran et al., 2016). Lower nitrate levels in dates may stem from reduced fertilizer use. Variability in nitrate levels can arise from factors such as soil type, fertilizer application, agricultural practices and groundwater contamination (Mehri et al., 2019). The results of a one-way ANOVA between nitrate, sites, varieties and hazard quotients for children and adults are displayed in Table 4. The results show a significant difference in nitrate concentration and hazard quotient between children and adults, with a difference of 0.008 at P<0.05. At the same time, there is no significant difference in nitrate concentration across sites or varieties.

Table 3: Pearson’s correlation matrix for nitrate concentrations in dates varieties.



Table 4: ANOVA Variance of nitrate against sites, varieties and Hazards quotient.



Fig 2: Dendrogram displaying hierarchical clustering for nitrate in date varieties.

CONCLUSION

This survey was conducted to evaluate the concentrations of nitrate in selected palm dates and assess the estimated daily intake (EDI) and health risks using the Hazard Quotient (HQ) approach. Data indicated that the mean ± SD nitrate level ranged from 498.66±135.35 mg/kg in Tafsert to 1147.02±287.97 mg/kg in Tagayat. Based on the results, the nitrate concentration in all samples is lower than the permissible limit suggested. The total EDIs of nitrate through the consumption of dates were lower than the ADI level. HQ values of nitrate by the consumption of dates were <1, indicating that health risks associated with nitrate exposure were not significant. Therefore, the intake of nitrate through date consumption could be considered safe for consumers. Therefore, it is essential to sustainably conserve and manage date palm resources to ensure future agricultural and economic stability.
 
Author’s contritbutions
 
Mansour Awiadat Salem, Saeda Maatoq Ali Mohamed, Yasser Fathi Nassar . designed the study; Aisha Abdulgader Alshanoky, Masouda Mohamed Alshatory, Samera Musa Alwaleed. analyzed the data; Mansour Awiadat Salem, Yasser Fathi Nassarwrote the manuscript.

CONFLICT OF INTEREST

The authors declare no conflicts of interest.

REFERENCES


  1. Abd–Elrahman, S.H., Saudy, H.S., El–Fattah, D.A.A and Hashem, F.A. (2022). Effect of irrigation water and organic fertilizer on reducing nitrate accumulation and boosting lettuce productivity. J Soil Sci Plant Nutri. 22: 2144 - 2155. doi. org/10.1007/s42729-022-00799-8.

  2. Ajebe, E.G. and Bahiru, T.B. (2018). Spectrophotometric determination of nitrite and nitrate in some selected vegetables cultivated in adami tulu judo kombolicha district farms, Ethiopia. J. Anal Bioanal Tech. 9: 410. doi: 10.4172/2155-9872.1000410.

  3. Alakhdhari, S.A., Alzouam, F.M. and Salem, M.A (2025). Assessment of nitrate concentration in some leafy vegetables in brack alshatti local market. Wadi Alshatti University Journal of Pure and Applied Sciences. 3(1): 44 - 51. doi.org/10. 63318/waujpasv3i2_05.

  4. Al-Busaidi, A., Shaharoona, B., Al-Yahyai, R and Ahmed, M (2015). Heavy metal concentrations in soils and ate palms irrigated by groundwater and treated wastewater. Pak J. Agri Sci. 51(1): 129-134.

  5. Al-Ethawi, L.A and Salem, M. A. (2019). Study of residual effect of N fertilizer (Total N) on the soil. J. Phys.: Conf. Ser. 1294 072001. doi:10.1088/1742-6596/1294/7/072001.

  6. Ali, R.A., Muhammad, K.A and Qadir, O.K (2021). A survey of nitrate and nitrite contents in vegetables to assess the potential health risks In Kurdistan, Iraq. Iop Conf. Series: Earth and Environmental Science. 910: 012065 IOP Publishing. doi.org/10.1088/1755-1315/910/1/012065 1.

  7. Ashworth, A., Mitchell, K., Blackwell, J.R., Vanhatalo, A and Jones, A.M. (2015). High-nitrate vegetable diet increases plasma nitrate and nitrite concentrations and reduces blood pressure in healthy women. Public Health Nutr.18(14): 2669 - 2678. doi.org/10.1017/S1368980015000038. 

  8. Bahadoran, Z., Mirmiran, P., Jeddi, S., Azizi, F., Ghasemi, A. and Hadaegh, F. (2016). Nitrate and nitrite content of vegetables, fruits, grains, legumes, dairy products, meats and processed meats. J. Food Compost. Anal. 51: 93-105. doi: 10.1016/ j.jfca.2016.06.006.

  9. Bolaji, O.T., Adeyeye, S.A.O and Akinboyo, B.E (2025). Quality evaluation of bread produced from wheat flour (triticum aevistivum) fortified with date flour (Phoenix dactylifera L.) olusola timothy. Asian Journal of Dairy and Food Research. 44(4): 653-659. doi: 10.18805/ajdfr.DRF-258.

  10. Chung, S.W., Tran, J.C., Tong, K.S., Chen, M.Y., Xiao, Y., Ho, Y.Y and Chan, C.H (2011). Nitrate and nitrite levels in commonly consumed vegetables in Hong Kong. Food Addit Contam Part B Surveill. 4(1): 34-41. doi.org/ 10.1080/19393210. 2011.557784.

  11. Dezhangah, S., Nazarib, F., Kamalic K., Hosseinid, M.J. and Mehrasbi, M.R. (2022). A survey on nitrate level in vegetables to assess the potential health risks in Iran. Int. J of food properties. 25(1): 1958-1973. doi.org/10.1080/10942912. 2022.2117377.

  12. Djahed, B., Taghavi, M., Farzadkia, M., Norzaee, S. and Miri, M. (2018). Stochastic exposure and health risk assessment of rice contamination to the heavy metals in the market of Iranshahr, Iran. Food and Chem. Toxicol. 115: 405-412. doi.org/10. 1016/j.fct.2018.03.040.

  13. Dong, C., Chu, Z., Wang, M., Qin, Y., Yi, Z., Liu, H. and Fu, Y. (2018). Influence of nitrogen source and concentrations on wheat growth and production inside “Lunar Palace-1”. Acta Astronautica. 144: 371- 379. https://doi.org/10.1016/j. actaastro.2017.12.043.

  14. Environmental Protection Agency (EPA) (1989). Risk assessment guidance for superfund, Vol. I, Human health evaluation manual (Part A) Dec. 1989, http://www.epa.gov/oswer/ riskassessment/ragsa/pdf/rags-vol1-pta_complete.pdf. Accessed 17 April 2011.

  15. El-Nahhal, Y. (2018). Nitrate residues in fruits, vegetables and bread samples and their health consequences. Health. 10: 487-501. doi.org/10.4236/health.2018.104039.

  16. European Food Safety Authority (EFSA). (2008). Nitrate in vegetables scientific opinion of the panel on contaminant in the food chain. The EFSA Journal. 69: 1-79

  17. Fashaho, A., Musandu, A.O., Lelei, J.J., Mwonga, S.M., Ndegwa, G.M. (2020). Effects of nitrogen and phosphorus fertilizer rates on maize (Zea mays L.) growth and yields in terraced lands of medium and high altitude regions of rwanda. Agricultural Science Digest. 40(3): 242-248. doi: 10. 18805/ag. D-176.

  18. Ghasemidehkordi, A., Malekirad, A.A., Nazem, H., Fazilati, M., Salavati, H., Shariatifar, N., Rezaei, M, Fakhri, Y. and Khaneghah, A.M. (2018). Concentration of lead and mercury in collected vegetables and herbs from Markazi province, Iran: A non-carcinogenic risk assessment. Food and Chem. Toxicol. 113: 204-210. doi.org/10.1016/j.fct.2018.01.048.

  19. Gruszecka-Kosowska, A. and Baran, A. (2017). Concentration and health risk assessment of nitrates in vegetables from conventional and organic farming. Human and ecological risk assessment: An International Journal. 23(4): 727-740. https://doi.org/10.1080/10807039.2016. 1277414.

  20. Hammami, Z., Mahmoudi, H., Al Janaahi, A and Singh, R.K (2024). Evaluation of date palm fruits quality under different irrigation water salinity levels compared to the fruit available in the market. Front. Sustain. Food Syst. 7: 1322350. doi. org/10.3389/fsufs.2023.1322350.

  21. Hmeljak Gorenjak, A. and Cenciè, A. (2013). Nitrate in vegetables and their impact on human health. A review. Acta Alimentaria. 42(2): 158-172. http://dx.doi.org/10.1556/AAlim.42. 2013.2.4.

  22. Jalali, M., Farsani, Z.A., Mogharab, M.H.G and Feyzian, M. (2021). Potential health risk of nitrate accumulation in vegetables grown in pol-e dokhtar county. Journal of Chemical Health Risks. 11(1): 99-111. doi: 10.22034/jchr.2020.1900860. 1137.

  23. Jannat, B., Mohamadi, S., Abdoli, N., Zienali, T. and Sadighara, P. (2022). The nitrate content of commonly consumed agricultural products including vegetables, cereals and legumes in Iran. Journal of Chemical Health Risks. 12(2): 293-303. doi.org/10.22034/jchr.2021.1936942.1371.

  24. Kaur, A., Satyavan., Yadav, A.K., Prakash, R and Singh, V. (2025). Optimum nitrogen dose and malt quality of barley varieties under saline water irrigation. Agricultural Science Digest. 45(3): 429-434. doi: 10.18805/ag. D-6037.

  25. Luetic, S., Knezovic, Z., Jurcic, K., Majic, Z., Tripkovic, K and Sutlovic, D. (2023). Leafy vegetable nitrite and nitrate content: potential health effects. Foods. 12: 1655. doi.org/10. 3390/foods12081655.

  26. Lufei, Z. and Yong, W. (2017). Nitrate assay for plant tissues. Bio-protocol. 7(2): e2029. doi.org/10.21769/BioProtoc.2029.

  27. Mehri, F., Heshmati, A., Moradi, M. and Khaneghah, A.M. (2019). The concentration and health risk assessment of nitrate in vegetables and fruits samples of Iran. Toxin Reviews.  40(4): 1215 - 1222. doi.org/10.1080/15569543.2019. 1673424.

  28. Mensinga, T.T., Speijers, G.J and Meulenbelt, J. (2023). Health implications of exposure to environmental nitrogenous compounds. Toxicol. Rev. 22(1): 41 - 51. doi.org/10.2165/00139709- 200322. 

  29. Pardo-Marín, O., Yusà-Pelechàm, V., Villalba-Martín, P and Perez- Dasí, J.A (2010). Monitoring programme on nitrates in vegetables and vegetable-based baby foods marketed in the Region of Valencia, Spain: levels and estimated daily intake. Food Addit Contam Part A. Chem Anal Control Expo Risk Assess. 27(4): 478-86. doi.org/ 10. 1080/19440040903439804. 

  30. Qasemi, M., Ghorbani, M., Salehi, R., Attari, S.M., Afsharnia, M., Dehghani, M.H., Farhang, M., Zarei, A., Gholinejad, A. and Zarei, A. (2024). Human health risk associated with nitrates in some vegetables: A case study in Gonabad. Food Chemistry Advances. 4: 100721. doi.org/10.1016/j.focha.2024.100721.

  31. Quijano, L., Yusà, V., Font, G., McAllister, C., Torres, C. and Pardo, O. (2017). Risk assessment and monitoring programme of nitrates through vegetables in the Region of Valencia (Spain). Food and Chem. Toxicol. 100: 42-49.  doi.org/ 10.1016/j.fct.2016.12.010

  32. Racchi, M.L. and Camussi, A (2018). The date palms of Al Jufrah - Libya: A survey on genetic diversity of local varieties. J. of Agri. and Environ. for Int. Devel. (JAEID). 112(1): 161-184. doi: 10.12895/jaeid.20181.776.

  33. Racchi, M.L., Bove, A., Turchi A., Bashir, G., Battaglia, M. and Camussi, A. (2014). Genetic characterization of Libyan date palm resources by microsatellite markers. Biotech. 4(1): 21-32. doi.org/10.1007/s13205-013-0116-6. 

  34. Radfard, M., Rahmatinia, M., Tabatabaee, H., Solimani, H., Mahvi, A.H and Azhdarpoor, A. (2018). Data on health risk assessment to the nitrate in drinking water of rural areas in the Khash city, Iran. Data Brief. 3(21): 1918-1923. doi. org/ 10.1016/j.dib.2018.11.007. 

  35. Ram, M., Afshari, A., Tavakoly, Sany, S. A and Jamshidi, A (2022). Health risk assessment and evaluation of nitrate and nitrite in salad vegetables of Mashhad City. J. Nutri. Fast Health. 10(4): 252-257. doi.org/ 10.22038/JNFH. 2022. 66532.1394.

  36. Saha, N. and Zaman, M (2013). Evaluation of possible health risks of heavy metals by consumption of foodstuffs available in the central market of Rajshahi City, Bangladesh. Environmental Monitoring and Assessment. 185(5): 3867-3878. doi: 10.1007/s10661-012-2835-2.

  37. Salehzadeh, H., Maleki, A., Rezaee, R., Shahmoradi, B. and Ponnet, K. (2020). The nitrate content of fresh and cooked vegetables and their health-related risks. PLoS ONE. 15(1): e0227551. doi.org/10.1371/journal.pone.0227551.

  38. Salem, M.A., Bedade, D.K., Al-Ethawi. L and Al-waleed, S.M. (2020). Assessment of physiochemical properties and concentration of heavy metals in agricultural soils fertilized with chemical fertilizers. Heliyon. 6(10): (2020) e05224. doi: 10.1016/j.heliyon. 2020.e05224.

  39. Sayed, F. and Rezvan, E. (2014). Measuring nitrate and nitrite concentrations in vegetables, fruits in Shiraz. J. of appl. Sci. and Enviro. 18(3): 451-457. https://doi.org/10.4314/ jasem.v18i3.12.

  40. Khan, A., Naeem M., Zekker I., Arian, M, Balal., Michalski, G., Khan, A., Shah, N., Zeeshan, S., Ul Haq, H. et al. (2021). Evaluating groundwater nitrate and other physicochemical parameters of the arid and semi-arid district of DI Khan by multivariate statistical analysis, Environmental Technology. doi: 10.1080/09593330.2021.1987532.

  41. Sebaei, A.S and Refai, H.M. (2019). Hazard index: Probabilistic risk exposure of nitrate and nitrite in Egyptian fruits and vegetables. Int. J of Enviro. Anal. Chem. 101(10): 1477 -1484. doi.org/10.1080/03067319.2019.1685666.

  42. Shahdadi, F., Mirzaei, H.O and Garmakhany D.A. (2015). Study of phenolic compound and antioxidant activity of date fruit as a function of ripening stages and drying process. J. Food Sci Technol. 52(3): 1814 -1819. doi.org/10.1007/s 13197-013-1177-6.

  43. Uddin, R., Thakur, M.U., Uddin, M.Z and Islam, G.M.R (2021).  Study of nitrate levels in fruits and vegetables to assess the potential health risks in Bangladesh. Sci. Rep. 11: 4704. doi.org/10.1038/s41598-021-84032-z.

  44. United states environmental protection agency (USEPA, 2020). Human Health Risk Assessment: https://www.epa.gov/ risk/human-healthrisk-assessment.

  45. USEPA (2004) Risk Assessment Guidance for Superfund (Human Health Evaluation Manual). USA. Environmental Protection Agency, Washington, DC (USA). Office of Solid Waste. http://www.epa.gov/oswer/riskassessment/.

  46. Zendehbad, M., Mostaghelchi, M., Mojganfar, M., Cepuder, P and Loiskandl, W, (2022). Nitrate in groundwater and agricultural products: Intake and risk assessment in northeastern Iran. Environ. Sci. Pollut. Res. 29: 78603 - 78619. doi.org/ 10.1007/s11356-022-20831-9.

  47. Zhao, L and Wang, Y (2017). Nitrate assay for plant tissues. Bio- Protocol. 7(2): e2029. doi.org/ 10.21769/BioProtoc.2029. 
Published In
Asian Journal of Dairy and Food Research
Article Metrics
Metrics Icon
0
Views
0
Citations
Reviewed By
Share Article
Download Article
In this Article
    Contact us
    Follow us

    Full Research Article

    Estimation of Nitrate Contents in Sixteen Varieties of Libyan Dates (Phoenix dactylifera L.) and Their Potential Health Risks

    M
    Mansour Awiadat Salem1
    http://orcid.org/0000-0002-2990-9045
    A
    Aisha Abdulgader Alshanoky2
    http://orcid.org/0009-0008-4575-9084
    M
    Masouda Mohamed Alshatory1
    http://orcid.org/0009-0001-7391-5290
    S
    Samera Musa Alwaleed2
    http://orcid.org/0009-0006-6474-6372
    S
    Saeda Maatoq Ali Mohamed3
    http://orcid.org/0009-0002-3916-6078
    S
    Saeda Maatoq Ali Mohamed4
    http://orcid.org/0000-0002-9675-8304
    1Department of Environmental Sciences, Faculty of Environment and Natural Resources, Wadi Alshatti University. Brack, Libya.
    2Department of Chemistry, Faculty of Sciences, Wadi Alshatti University. Brack, Libya.
    3Department of Zoology, Faculty of Sciences, Sebha University. Sebha, Libya.
    4Department of Mechanical and Renewable Energy Engineering, Faculty of Engineering, Wadi Alshatti University, Wadi Alshatti, Libya.

    ABSTRACT

    Background: Dates play an essential role in the Libyan diet, particularly during Ramadan. As a result, there is considerable emphasis on ensuring that these dates are free from contaminants, especially nitrates, which are prevalent pollutants in food items. Therefore, this study aimed to evaluate the nitrate contents and the potential health risks associated with their consumption by adults and teenagers in various date varieties commonly consumed in Libya.

    Methods: A total of sixteen date varieties, mainly gathered from southern Libya, were tested. The findings reveal that the average nitrate content in the date samples ranged between 498.66±135.35 mg/kg in the Tafsert variety and 1147.02±287.97 mg/kg in the Tagayat variety. To determine the potential health risks and safety of these dates, we assessed the Estimated Daily Intake (EDI), Acceptable Daily Intake (ADI) and Hazard Quotient (HQ).

    Result: The results indicate that the EDI, ADI and HQ values remained below the thresholds established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The EDI for nitrates was observed to range from 0.34 to 0.77 mg/kg body weight (bw)/day for adults and from 0.45 to 1.04 mg/kg bw/day for teenagers, while the acceptable limit is defined at 3.70 mg/kg bw/day. However, the findings also suggest that teenagers are more susceptible to nitrate levels in dates than adults. Therefore, the amount of dates consumed does not represent a risk to consumers. Additionally, the calculated HQ values for adults and teenagers varied from 0.21 to 0.48 and from 0.28 to 0.65, respectively. Since these HQ values are below 1, they indicate a low level of health risk for consumers.

    INTRODUCTION

    There are approximately 5,000 varieties of date palms worldwide, with 160 million palms cultivated in the Arab region, yielding about 6.6 million tons annually, which accounts for over 77% of global date production (Hammami et al., 2024). Dates are nutritious fruits that are rich in essential vitamins, minerals, dietary fiber and antioxidants. They promote heart health, aid in digestion and help reduce oxidative stress and inflammation. Dates provide important nutrients, including carbohydrates, proteins, fats, vitamins A and C and minerals such as calcium, iron and magnesium (Shahdadi et al., 2015). Most human nitrate exposure comes from plant-based foods, especially vegetables and certain fruits, accounting for 80% to 95% of daily intake (Pardo-Marín  et al., 2010; Quijano et al., 2017; Qasemi et al., 2024). Dates also contain antioxidants that may inhibit cancer-causing agents, influencing some countries to relax regulations on vegetable nitrate levels (Jannat et al., 2022). Low levels of nitrate are generally considered safe, with the Joint Expert Committee on Food and Agriculture (JECFA) recommending an acceptable daily intake (ADI) of 0-3.7 mg per kilogram of body weight (Hmeljak and Cencič (2013). The type of nitrogen significantly affects plant growth, with primary forms including ammonium (NH4+), nitrate (NO3-) and urea. Different plant species exhibit preferences for these sources, influenced by factors such as nitrogen levels and soil properties (Dong et al., 2018; Al-Ethawi and Salem, 2019). The overuse of chemical fertilizers leads to issues such as soil acidification and groundwater contamination (Salem et al., 2020; Fashaho et al., 2020). Reports indicate alarming levels of heavy metals and nitrates in crops, often due to the irrigation with partially treated sewage water and excessive fertilizer application (Al-Busaidi  et al., 2015; Salehzadeh et al., 2020; Jalali et al., 2021), raising concerns about food safety (El-Nahhal, 2018; Abd-Elrahman  et al., 2022). High nitrate levels can be converted into harmful compounds, such as nitrosamines, while nitrite production can interfere with oxygen transport in the blood (Mensinga et al., 2023; Bolaji et al., 2025). Interestingly, nitrates and nitrites may lower blood pressure in healthy women (Ashworth et al., 2015). Date palms, a key fruit crop in arid regions like Libya, contribute significantly to local economies and are cultivated in over 400 varieties (Racchi and Camussi, 2018). Despite extensive research on heavy metal and nitrate contamination in food, there is a limited number of studies on nitrates in palm dates. This study aims to examine the nitrate content in the studied dates and assess the potential health risks associated with their consumption.

    MATERIALS AND METHODS

    Study area and sample collection
     
    The cultivation of date palms (Phoenix dactylifera L.) has grown significantly in Libya, with an estimated four million trees, mainly in the southern Saharan region (Racchi et al., 2014). Ripe dates are harvested by the end of October. In November 2024, samples of sixteen local date varieties, Degla, Asapeer, Tafsert, Taleas, Awrayag, Aglyen, Ammrayer, Saeyde, Adawy, Sallalow, Akdayer, Tagayat, Apil, Kadray, Majdool and Ajwa, were purchased from the market and brought to the laboratory for analysis.
     
    Preparation of palm date samples
     
    Date palm samples were prepared following the methods of Ajebe and Bahiru (2019) and Zhao and Wang (2017). One hundred grams of each variety were washed, pitted and cut into uniform pieces, then dried in an oven at 105°C for 24 hours. After cooling, the samples were ground and sieved through a 2 mm mesh. Finally, 4.0 grams of each sample were stored in clean plastic bottles for analysis.
     
    Extraction and determination of nitrate in dates
     
    Nitrate extraction was performed as per Lufei and Yong (2017). A 0.1 g date sample was suspended in 10 mL distilled water, heated to 80oC for 1 hour, cooled and filtered through Whatman filter paper No. 4. For nitrate determination, 0.1 mL of the extract was mixed with 0.4 mL salicylic acid solution in a 30 mL tube, allowed to sit for 20 minutes and then 9.5 mL of 2 N NaOH was added. The nitrate concentration was measured immediately using a Jenway 7205 spectrophotometer, following Equation (1).
     
     
      
    Where,
    Y = Nitrate content (mg/kg dwt).
    C = Nitrate concentration from OD410 (abs * slope - intercept) using the calibration curve.
    V = Total volume of extracted sample (ml).
    W = Weight of sample (g).
     
    Health risk assessment
     
    A study evaluated the health risks associated with date consumption in adults and teenagers, focusing on nitrate levels in various date varieties. The average daily intake was estimated at 110 g for adults and 70 g for teenagers. The estimated daily intake (EDI), percentage of acceptable daily intake (%ADI) and hazard quotient (HQ) were calculated as per Ram et al., (2022).
     
    Estimated daily intake (EDI)
     
    People can be exposed to pollutants through ingestion, skin contact and inhalation; however, for nitrates, the primary exposure route is oral intake (Qasemi et al., 2024). Excessive nitrate consumption from palm dates can pose health risks if it exceeds the Acceptable Daily Intake (ADI) of 3.7 mg per kilogram of body weight, as set by the European Food Safety Authority (EFSA, 2008). Adults consume about 110 g, while teenagers consume around 70 g of palm dates daily. High nitrate intake can lead to serious health problems or fatalities (Dezhangah et al., 2022). We calculated the average daily nitrate intake based on body weight and bioavailability using the Estimated Daily Intake (EDI) equation, which reflects potential ingestion but does not consider metabolic excretion (USEPA, 2004).
     
      
      
    Where:
    EDI = Estimated daily intake (mg/kg bw/day).
    EF = Exposure frequency (365 days/year).
    ED = The exposure duration, which is 70 years for adults and 50 years for teenagers. For teens (7-17 years), the maximum exposure duration is 11 years, while adults over 70 can have a maximum of 30 years (EPA, 1989).
    DC indicates daily date consumption: ~110 g/day for Libyan adults (70 kg) and ~70 g/day for teenagers (50 kg), potentially doubling during Ramadan.
    MC = Mean nitrate concentration in samples (mg/kg dry weight). BW is the body weight of adult consumers (70 kg) and teenagers (50 kg) (Radfard et al., 2018).
    AT = Average Time: 25,550 days for adults and 18,250 days for children (Saha and Zaman, 2013).
     
    Noncarcinogenic hazard quotient (NHQ)
     
    Human health risk assessment, as defined by the U.S. Environmental Protection Agency (USEPA, 2004), estimates the likelihood of adverse health effects from chemical exposure in contaminated environments. This study conducted a quantitative risk assessment of nitrate exposure from date consumption, utilizing data from the USEPA (2020). The reference dose (RfD) for nitrate is 1.60 mg/kg body weight per day (Gruszecka-Kosowska and Baran, 2017). The Hazard Quotient (HQ) compares individual exposure to the RfD: an HQ > 1 indicates a significant health risk, while HQ < 1 suggests safe exposure levels (Djahed et al., 2018).
     
    Statistical analysis
     
    All experiments were conducted in triplicate and SPSS version 26 was employed to calculate the minimum, maximum, mean and standard deviation of nitrate levels for the dates under study. The Pearson correlation coefficient (r) was utilized to assess the linear relationships among the various data varieties. The tested date varieties were categorized based on their nitrate content using Ward’s hierarchical clustering analysis. A one-way analysis of variance (ANOVA) was performed to compare the mean nitrate concentrations across the different date varieties. The threshold for statistical significance was set at p<0.05 (Dezhangah et al., 2022).
     
    Validation method
     
    The validation method focused on data types, permissible limits and process performance characteristics, including precision, accuracy, calibration data and the linearity of the calibration curve (Dezhangah et al., 2022). A linear calibration curve was established using nitrate standards from 10 to 120 mg/L, with three replicates per concentration. Deionized water served as a blank sample to determine the Limits of Quantitation  (LOQ) and Limits of Detection (LOD) (Mehri et al., 2019).

    RESULTS AND DISCUSSION

    Calibration curve and validation method
     
    The calibration equation, which links the analyte to nitrate concentration, was used to determine the nitrate content in palm dates. A calibration curve (Fig 1) was created by measuring seven concentrations of NO3, ranging from 0.0 to 120 mg/L, with samples exceeding this range diluted for reassessment. A multiple linear regression model showed a strong correlation coefficient (R2) of 0.9953. The limits of detection and quantification for NO3- were 6.670 mg/kg and 20.211 mg/kg, respectively. Comparable results were reported by Pardo-Marín  et al. (2010) with a LOD of 7 mg/kg and a LOQ of 20 mg/kg and by Chung et al., (2011) with a LOD of 4 mg/kg and a LOQ of 20 mg/kg.

    Fig 1: Nitrate standard curve.


     
    Nitrate content in palm dates
     
    Table 1 shows the nitrate content of various palm date varieties from Brack City’s local market. The mean nitrate levels (mean ± SD in mg/kg dwt) were as follows: Degla (735.38±464.67), Asapeer (1012.31±277.69), Tafsert (498.65±135.35), Tales (711.27±173.94), Awrayag (637.48±295.77), Aglyen (708.62±218.36), Ammrayer (695.87±69.78), Saeyde (734.52±288.90), Adawy (500.26±56.41), Sallalow (712.43±198.29), Akdayer (676.27±112.36), Tagayat (1085.65±335.46), Apil (798.53±378.75), Kadray (627.73±6.12), Majdool (758.63±198.25) and Ajwa (812.53±38.9). Tafsert exhibited the lowest nitrate content, whereas Tagayat had the highest. The reduced nitrate levels in Tafsert are likely due to cultivation in an oasis without irrigation or fertilisers. Additionally, soil properties and cultivation practices significantly influence nitrate content (Alakhdhari et al., 2025; Kaur et al., 2025). The nitrate levels in our samples are moderate (500-1000 mg/kg), according to Hmeljak and Cenciè (2013). Although permissible limits for dates are not specified in the literature, we reference recommendations from Sayed and Rezvan (2014).

    Table 1: Descriptive analysis of Conc. of Nitrate in palm dates varieties (local name) (mg/kg. dwt).


     
    Health risk assessment
     
    Estimated daily intakes of nitrate
     
    Some individuals consume palm dates daily, while others do so occasionally; this study focuses on individuals who consume them daily. The estimated daily nitrate intakes (EDI) for adults (70 kg) and teenagers (50 kg) are outlined in Table 2, showing higher nitrate levels in teenagers. Daily consumption was estimated at 110 g for adults and 70 g for teenagers, with nitrate exposure varying from 132.92 to 305.87 mg/day for adults and 95.63 to 219.97 mg/day for teenagers. The acceptable daily intake of nitrate is 0-3.7 mg/kg body weight/day (Luetic et al., 2023), equating to 259 mg for adults and 185 mg for teenagers. Although Asapeer and Tagayat have high nitrate levels (1012.31 and 1147.0 mg/kg), they remain within JECFA’s recommended limits.

    Table 2: Estimated daily intake, mean nitrate intake and Hazards quotient of nitrate from consumption dates varieties.


     
    Acceptable daily intake (ADI)
     
    Nitrate toxicity can arise from the daily consumption of foods like dates. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has set an acceptable daily intake (ADI) for nitrates at 3.70 mg/kg body weight per day (EFSA, 2008). The %ADI from date consumption for adults and teenagers ranges from 9.08 - 12.21 and 20.88 - 28.08 for Tafsert and Tagayat, respectively. Mean nitrate intake for adults is 0.71 to 1.64 mg/kg/d and for teenagers, it is 1.0 to 2.29 mg/kg/d. Both are within the acceptable limit. Higher ADI values have been observed in some fruits and vegetables in Iran, Bangladesh and Egypt due to high EDI (Mehri et al., 2019; Sebaei and Refai, 2019; Uddin et al., 2021; Zendehbad et al., 2022).
     
    Noncarcinogenic risk
     
    Several factors influence health risks associated with nitrates, including consumption frequency, inherent risk and individual body weight (Mehri et al., 2019; Ali et al., 2021). Our findings indicate that the Hazard Quotient (HQ) values for all date samples were below 1, suggesting no noncarcinogenic risks associated with date consumption. Specifically, HQ values for nitrates ranged from 0.21 in Tafsert to 0.46 in Tagayat for adults consuming 110 g/day and from 0.28 to 0.65 for teenagers consuming about 70 g/day. The risk from nitrates may vary based on date type, environmental factors, farming practices and storage conditions (Ghasemidehkordi et al., 2018). Notably, teenagers show higher HQ values than adults, indicating they are more vulnerable to nitrate concentrations in dates. Our results align with findings from Mehri et al., (2019), Ali et al., (2021) and Qasemi et al., (2024).
     
    Statistical analysis
     
    The Pearson correlation coefficient demonstrated a strong association between specific date varieties and their nitrate concentrations, highlighting significant relationships among several of these varieties. These findings will enhance the management of polluted dates, ultimately helping to mitigate the risks they pose to consumers. (Khan et al., 2021). Table 3 depicts Pearson’s correlation matrix for nitrate accumulation in the sixteen varieties of dates (Shown in bold). The results show a strong positive correlation between Deagla and Aurag (r = 0.798), Asaper and Selalew (r = 1.000), Tafsert and Saedi (r = 0.793), Talesh and Tagayat (r = 0.921), Aurag and Saedi (r = 0.872), Agder and Kadray (r =1.000) and Tagayat and Apel (r = 0.994). A positive correlation was observed between Asaper and Aurag (r = 0.852), Tafsert and Aurag (r = 0.581) and Talesh and Apel (r = 0.885). Whereas, strong negative correlations were observed between Deagla and Tagayat (r =- 0.948) and between Asaper and Tagayat (r = -0.923), respectively and between Deagla and Apel (r =- 0.946) and between Asaper and Apel (r = -0.947), respectively. Talesh, Aurag and Saedi (r = -0.895, r = -0.944) respectively. Saedi, Tagayat and Apel (r = -0.970, r = -0.962) respectively. Negative correlation observed only between Tafsert, Tagayat and Apel (r = -0.909, r = -0.899, respectively). Aurag, Tagayat and Apel (r = -0.903, r = -0.891). Fig 2 illustrates the hierarchical clustering of nitrate accumulation in dates, revealing three distinct clusters. The first cluster includes Tagayat and Apel. The second cluster comprises Aurag, Tafsert, Saedi, Deegla, Adwai and Asaper. The third cluster consists of Majdawal, Agdar, Salalew, Amrear, Kadray, Aglen, Ajwa and Talesh (Bahadoran et al., 2016). Lower nitrate levels in dates may stem from reduced fertilizer use. Variability in nitrate levels can arise from factors such as soil type, fertilizer application, agricultural practices and groundwater contamination (Mehri et al., 2019). The results of a one-way ANOVA between nitrate, sites, varieties and hazard quotients for children and adults are displayed in Table 4. The results show a significant difference in nitrate concentration and hazard quotient between children and adults, with a difference of 0.008 at P<0.05. At the same time, there is no significant difference in nitrate concentration across sites or varieties.

    Table 3: Pearson’s correlation matrix for nitrate concentrations in dates varieties.



    Table 4: ANOVA Variance of nitrate against sites, varieties and Hazards quotient.



    Fig 2: Dendrogram displaying hierarchical clustering for nitrate in date varieties.

    CONCLUSION

    This survey was conducted to evaluate the concentrations of nitrate in selected palm dates and assess the estimated daily intake (EDI) and health risks using the Hazard Quotient (HQ) approach. Data indicated that the mean ± SD nitrate level ranged from 498.66±135.35 mg/kg in Tafsert to 1147.02±287.97 mg/kg in Tagayat. Based on the results, the nitrate concentration in all samples is lower than the permissible limit suggested. The total EDIs of nitrate through the consumption of dates were lower than the ADI level. HQ values of nitrate by the consumption of dates were <1, indicating that health risks associated with nitrate exposure were not significant. Therefore, the intake of nitrate through date consumption could be considered safe for consumers. Therefore, it is essential to sustainably conserve and manage date palm resources to ensure future agricultural and economic stability.
     
    Author’s contritbutions
     
    Mansour Awiadat Salem, Saeda Maatoq Ali Mohamed, Yasser Fathi Nassar . designed the study; Aisha Abdulgader Alshanoky, Masouda Mohamed Alshatory, Samera Musa Alwaleed. analyzed the data; Mansour Awiadat Salem, Yasser Fathi Nassarwrote the manuscript.

    CONFLICT OF INTEREST

    The authors declare no conflicts of interest.

    REFERENCES


    1. Abd–Elrahman, S.H., Saudy, H.S., El–Fattah, D.A.A and Hashem, F.A. (2022). Effect of irrigation water and organic fertilizer on reducing nitrate accumulation and boosting lettuce productivity. J Soil Sci Plant Nutri. 22: 2144 - 2155. doi. org/10.1007/s42729-022-00799-8.

    2. Ajebe, E.G. and Bahiru, T.B. (2018). Spectrophotometric determination of nitrite and nitrate in some selected vegetables cultivated in adami tulu judo kombolicha district farms, Ethiopia. J. Anal Bioanal Tech. 9: 410. doi: 10.4172/2155-9872.1000410.

    3. Alakhdhari, S.A., Alzouam, F.M. and Salem, M.A (2025). Assessment of nitrate concentration in some leafy vegetables in brack alshatti local market. Wadi Alshatti University Journal of Pure and Applied Sciences. 3(1): 44 - 51. doi.org/10. 63318/waujpasv3i2_05.

    4. Al-Busaidi, A., Shaharoona, B., Al-Yahyai, R and Ahmed, M (2015). Heavy metal concentrations in soils and ate palms irrigated by groundwater and treated wastewater. Pak J. Agri Sci. 51(1): 129-134.

    5. Al-Ethawi, L.A and Salem, M. A. (2019). Study of residual effect of N fertilizer (Total N) on the soil. J. Phys.: Conf. Ser. 1294 072001. doi:10.1088/1742-6596/1294/7/072001.

    6. Ali, R.A., Muhammad, K.A and Qadir, O.K (2021). A survey of nitrate and nitrite contents in vegetables to assess the potential health risks In Kurdistan, Iraq. Iop Conf. Series: Earth and Environmental Science. 910: 012065 IOP Publishing. doi.org/10.1088/1755-1315/910/1/012065 1.

    7. Ashworth, A., Mitchell, K., Blackwell, J.R., Vanhatalo, A and Jones, A.M. (2015). High-nitrate vegetable diet increases plasma nitrate and nitrite concentrations and reduces blood pressure in healthy women. Public Health Nutr.18(14): 2669 - 2678. doi.org/10.1017/S1368980015000038. 

    8. Bahadoran, Z., Mirmiran, P., Jeddi, S., Azizi, F., Ghasemi, A. and Hadaegh, F. (2016). Nitrate and nitrite content of vegetables, fruits, grains, legumes, dairy products, meats and processed meats. J. Food Compost. Anal. 51: 93-105. doi: 10.1016/ j.jfca.2016.06.006.

    9. Bolaji, O.T., Adeyeye, S.A.O and Akinboyo, B.E (2025). Quality evaluation of bread produced from wheat flour (triticum aevistivum) fortified with date flour (Phoenix dactylifera L.) olusola timothy. Asian Journal of Dairy and Food Research. 44(4): 653-659. doi: 10.18805/ajdfr.DRF-258.

    10. Chung, S.W., Tran, J.C., Tong, K.S., Chen, M.Y., Xiao, Y., Ho, Y.Y and Chan, C.H (2011). Nitrate and nitrite levels in commonly consumed vegetables in Hong Kong. Food Addit Contam Part B Surveill. 4(1): 34-41. doi.org/ 10.1080/19393210. 2011.557784.

    11. Dezhangah, S., Nazarib, F., Kamalic K., Hosseinid, M.J. and Mehrasbi, M.R. (2022). A survey on nitrate level in vegetables to assess the potential health risks in Iran. Int. J of food properties. 25(1): 1958-1973. doi.org/10.1080/10942912. 2022.2117377.

    12. Djahed, B., Taghavi, M., Farzadkia, M., Norzaee, S. and Miri, M. (2018). Stochastic exposure and health risk assessment of rice contamination to the heavy metals in the market of Iranshahr, Iran. Food and Chem. Toxicol. 115: 405-412. doi.org/10. 1016/j.fct.2018.03.040.

    13. Dong, C., Chu, Z., Wang, M., Qin, Y., Yi, Z., Liu, H. and Fu, Y. (2018). Influence of nitrogen source and concentrations on wheat growth and production inside “Lunar Palace-1”. Acta Astronautica. 144: 371- 379. https://doi.org/10.1016/j. actaastro.2017.12.043.

    14. Environmental Protection Agency (EPA) (1989). Risk assessment guidance for superfund, Vol. I, Human health evaluation manual (Part A) Dec. 1989, http://www.epa.gov/oswer/ riskassessment/ragsa/pdf/rags-vol1-pta_complete.pdf. Accessed 17 April 2011.

    15. El-Nahhal, Y. (2018). Nitrate residues in fruits, vegetables and bread samples and their health consequences. Health. 10: 487-501. doi.org/10.4236/health.2018.104039.

    16. European Food Safety Authority (EFSA). (2008). Nitrate in vegetables scientific opinion of the panel on contaminant in the food chain. The EFSA Journal. 69: 1-79

    17. Fashaho, A., Musandu, A.O., Lelei, J.J., Mwonga, S.M., Ndegwa, G.M. (2020). Effects of nitrogen and phosphorus fertilizer rates on maize (Zea mays L.) growth and yields in terraced lands of medium and high altitude regions of rwanda. Agricultural Science Digest. 40(3): 242-248. doi: 10. 18805/ag. D-176.

    18. Ghasemidehkordi, A., Malekirad, A.A., Nazem, H., Fazilati, M., Salavati, H., Shariatifar, N., Rezaei, M, Fakhri, Y. and Khaneghah, A.M. (2018). Concentration of lead and mercury in collected vegetables and herbs from Markazi province, Iran: A non-carcinogenic risk assessment. Food and Chem. Toxicol. 113: 204-210. doi.org/10.1016/j.fct.2018.01.048.

    19. Gruszecka-Kosowska, A. and Baran, A. (2017). Concentration and health risk assessment of nitrates in vegetables from conventional and organic farming. Human and ecological risk assessment: An International Journal. 23(4): 727-740. https://doi.org/10.1080/10807039.2016. 1277414.

    20. Hammami, Z., Mahmoudi, H., Al Janaahi, A and Singh, R.K (2024). Evaluation of date palm fruits quality under different irrigation water salinity levels compared to the fruit available in the market. Front. Sustain. Food Syst. 7: 1322350. doi. org/10.3389/fsufs.2023.1322350.

    21. Hmeljak Gorenjak, A. and Cenciè, A. (2013). Nitrate in vegetables and their impact on human health. A review. Acta Alimentaria. 42(2): 158-172. http://dx.doi.org/10.1556/AAlim.42. 2013.2.4.

    22. Jalali, M., Farsani, Z.A., Mogharab, M.H.G and Feyzian, M. (2021). Potential health risk of nitrate accumulation in vegetables grown in pol-e dokhtar county. Journal of Chemical Health Risks. 11(1): 99-111. doi: 10.22034/jchr.2020.1900860. 1137.

    23. Jannat, B., Mohamadi, S., Abdoli, N., Zienali, T. and Sadighara, P. (2022). The nitrate content of commonly consumed agricultural products including vegetables, cereals and legumes in Iran. Journal of Chemical Health Risks. 12(2): 293-303. doi.org/10.22034/jchr.2021.1936942.1371.

    24. Kaur, A., Satyavan., Yadav, A.K., Prakash, R and Singh, V. (2025). Optimum nitrogen dose and malt quality of barley varieties under saline water irrigation. Agricultural Science Digest. 45(3): 429-434. doi: 10.18805/ag. D-6037.

    25. Luetic, S., Knezovic, Z., Jurcic, K., Majic, Z., Tripkovic, K and Sutlovic, D. (2023). Leafy vegetable nitrite and nitrate content: potential health effects. Foods. 12: 1655. doi.org/10. 3390/foods12081655.

    26. Lufei, Z. and Yong, W. (2017). Nitrate assay for plant tissues. Bio-protocol. 7(2): e2029. doi.org/10.21769/BioProtoc.2029.

    27. Mehri, F., Heshmati, A., Moradi, M. and Khaneghah, A.M. (2019). The concentration and health risk assessment of nitrate in vegetables and fruits samples of Iran. Toxin Reviews.  40(4): 1215 - 1222. doi.org/10.1080/15569543.2019. 1673424.

    28. Mensinga, T.T., Speijers, G.J and Meulenbelt, J. (2023). Health implications of exposure to environmental nitrogenous compounds. Toxicol. Rev. 22(1): 41 - 51. doi.org/10.2165/00139709- 200322. 

    29. Pardo-Marín, O., Yusà-Pelechàm, V., Villalba-Martín, P and Perez- Dasí, J.A (2010). Monitoring programme on nitrates in vegetables and vegetable-based baby foods marketed in the Region of Valencia, Spain: levels and estimated daily intake. Food Addit Contam Part A. Chem Anal Control Expo Risk Assess. 27(4): 478-86. doi.org/ 10. 1080/19440040903439804. 

    30. Qasemi, M., Ghorbani, M., Salehi, R., Attari, S.M., Afsharnia, M., Dehghani, M.H., Farhang, M., Zarei, A., Gholinejad, A. and Zarei, A. (2024). Human health risk associated with nitrates in some vegetables: A case study in Gonabad. Food Chemistry Advances. 4: 100721. doi.org/10.1016/j.focha.2024.100721.

    31. Quijano, L., Yusà, V., Font, G., McAllister, C., Torres, C. and Pardo, O. (2017). Risk assessment and monitoring programme of nitrates through vegetables in the Region of Valencia (Spain). Food and Chem. Toxicol. 100: 42-49.  doi.org/ 10.1016/j.fct.2016.12.010

    32. Racchi, M.L. and Camussi, A (2018). The date palms of Al Jufrah - Libya: A survey on genetic diversity of local varieties. J. of Agri. and Environ. for Int. Devel. (JAEID). 112(1): 161-184. doi: 10.12895/jaeid.20181.776.

    33. Racchi, M.L., Bove, A., Turchi A., Bashir, G., Battaglia, M. and Camussi, A. (2014). Genetic characterization of Libyan date palm resources by microsatellite markers. Biotech. 4(1): 21-32. doi.org/10.1007/s13205-013-0116-6. 

    34. Radfard, M., Rahmatinia, M., Tabatabaee, H., Solimani, H., Mahvi, A.H and Azhdarpoor, A. (2018). Data on health risk assessment to the nitrate in drinking water of rural areas in the Khash city, Iran. Data Brief. 3(21): 1918-1923. doi. org/ 10.1016/j.dib.2018.11.007. 

    35. Ram, M., Afshari, A., Tavakoly, Sany, S. A and Jamshidi, A (2022). Health risk assessment and evaluation of nitrate and nitrite in salad vegetables of Mashhad City. J. Nutri. Fast Health. 10(4): 252-257. doi.org/ 10.22038/JNFH. 2022. 66532.1394.

    36. Saha, N. and Zaman, M (2013). Evaluation of possible health risks of heavy metals by consumption of foodstuffs available in the central market of Rajshahi City, Bangladesh. Environmental Monitoring and Assessment. 185(5): 3867-3878. doi: 10.1007/s10661-012-2835-2.

    37. Salehzadeh, H., Maleki, A., Rezaee, R., Shahmoradi, B. and Ponnet, K. (2020). The nitrate content of fresh and cooked vegetables and their health-related risks. PLoS ONE. 15(1): e0227551. doi.org/10.1371/journal.pone.0227551.

    38. Salem, M.A., Bedade, D.K., Al-Ethawi. L and Al-waleed, S.M. (2020). Assessment of physiochemical properties and concentration of heavy metals in agricultural soils fertilized with chemical fertilizers. Heliyon. 6(10): (2020) e05224. doi: 10.1016/j.heliyon. 2020.e05224.

    39. Sayed, F. and Rezvan, E. (2014). Measuring nitrate and nitrite concentrations in vegetables, fruits in Shiraz. J. of appl. Sci. and Enviro. 18(3): 451-457. https://doi.org/10.4314/ jasem.v18i3.12.

    40. Khan, A., Naeem M., Zekker I., Arian, M, Balal., Michalski, G., Khan, A., Shah, N., Zeeshan, S., Ul Haq, H. et al. (2021). Evaluating groundwater nitrate and other physicochemical parameters of the arid and semi-arid district of DI Khan by multivariate statistical analysis, Environmental Technology. doi: 10.1080/09593330.2021.1987532.

    41. Sebaei, A.S and Refai, H.M. (2019). Hazard index: Probabilistic risk exposure of nitrate and nitrite in Egyptian fruits and vegetables. Int. J of Enviro. Anal. Chem. 101(10): 1477 -1484. doi.org/10.1080/03067319.2019.1685666.

    42. Shahdadi, F., Mirzaei, H.O and Garmakhany D.A. (2015). Study of phenolic compound and antioxidant activity of date fruit as a function of ripening stages and drying process. J. Food Sci Technol. 52(3): 1814 -1819. doi.org/10.1007/s 13197-013-1177-6.

    43. Uddin, R., Thakur, M.U., Uddin, M.Z and Islam, G.M.R (2021).  Study of nitrate levels in fruits and vegetables to assess the potential health risks in Bangladesh. Sci. Rep. 11: 4704. doi.org/10.1038/s41598-021-84032-z.

    44. United states environmental protection agency (USEPA, 2020). Human Health Risk Assessment: https://www.epa.gov/ risk/human-healthrisk-assessment.

    45. USEPA (2004) Risk Assessment Guidance for Superfund (Human Health Evaluation Manual). USA. Environmental Protection Agency, Washington, DC (USA). Office of Solid Waste. http://www.epa.gov/oswer/riskassessment/.

    46. Zendehbad, M., Mostaghelchi, M., Mojganfar, M., Cepuder, P and Loiskandl, W, (2022). Nitrate in groundwater and agricultural products: Intake and risk assessment in northeastern Iran. Environ. Sci. Pollut. Res. 29: 78603 - 78619. doi.org/ 10.1007/s11356-022-20831-9.

    47. Zhao, L and Wang, Y (2017). Nitrate assay for plant tissues. Bio- Protocol. 7(2): e2029. doi.org/ 10.21769/BioProtoc.2029. 
    In this Article
      Contact us
      Follow us
      Published In
      Asian Journal of Dairy and Food Research

      Editorial Board

      View all (0)