Estimation of heavy metal concentrations in imported frozen meat sold in the Libyan market

Mediterranean Journal of ISSN: 2789-1895 https://mrj.org.ly Medical Research Mediterr J Med Res Altalibet al. Mediterr J Med Res. 2025; 2(4): 276-282. Page 276 ORIGINAL RESEARCH article Estimation of heavy metal concentrations in imported frozen meat sold in the Libyan market Somia A. Altalib 1 , Ali A. Ghania 2 , and Aiman A. Alazzabi 1 * 1 Department of Medical Technology, Rowad Alelm University, and 2 Center for Food and Drug Control, Tripoli, Libya * Author to whom correspondence should be addressed Received: September 20, 2025, Accepted: December 15, 2025, Published online: December 19, 2025 HOW TO CITE THIS Altalib et al. Estimation of heavy metal concentrations in imported frozen meat sold in the Libyan market. Mediterr J Med Res. 2025; 2(4): 276-282. [Article number: 32]. https://doi.org/10.5281/zenodo.17986261 Keywords: Cadmium, chromium, food safety, heavy metal, lead, imported frozen meat Abstract: Heavy metals are chemical elements with a toxic effect on human and animal bodies. The expansion of industries has led to substantial increases in the levels of these heavy metals in the environment. This study examines the levels of heavy metal contamination in imported frozen meat, given its importance for food safety and consumer health. A total of 30 meat samples (including chicken, beef, lamb, and some processed products) were randomly collected from various commercial markets in Tripoli. Following acid digestion, concentrations of lead, cadmium, chromium, and copper were determined using Atomic Absorption Spectrophotometry. All samples complied with Libyan and International safety limits for cadmium, chromium or copper, while only one sample (3.3%) exceeded the permissible limit for lead. Statistical analysis revealed no significant variation in lead, cadmium, or chromium concentrations across meat types, cuts, or countries of origin. Copper levels, however, varied significantly by meat type. These findings indicate the overall safety of imported meat products regarding heavy metal contamination, although continuous monitoring remains essential. Introduction Meat plays a vital role in human nutrition due to its high-quality protein and essential micronutrient content, including iron, zinc, selenium, and vitamin B12 [1]. In Libya, meat-especially poultry, lamb, camel, and beef-is a central dietary component, with an estimated daily per capita availability of 86 grams [2]. Nevertheless, contamination of food, food supplements and meat with heavy metals poses significant public health risks [3-5]. These metals can enter the food chain through contaminated animal feed and water sources affected by industrial and agricultural pollutants. Due to their non-biodegradable nature and long biological half-lives, heavy metals accumulate in the environment and organisms [6]. Chronic dietary exposure to lead (Pb) and cadmium (Cd) has been associated with renal, hepatic, neurological, and cardiovascular diseases [7]. To address these risks, international bodies such as the World Health Organization (WHO) and Codex Alimentarius have established maximum allowable levels for heavy metals in food [8]. However, studies have revealed that meat products from many regions, particularly parts of Africa and Asia, often exceed these limits [9]. This study aims to quantify the concentrations of Pb, Cd, chromium (Cr), and copper (Cu) in imported frozen meat available in Tripoli markets and evaluate their compliance with established safety standards. Copyright© 2025. This open-access article is distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Mediterranean Journal of ISSN: 2789-1895 https://mrj.org.ly Medical Research Mediterr J Med Res Altalibet al. Mediterr J Med Res. 2025; 2(4): 276-282. Page 277 Materials and methods Study design and sample collection: This cross-sectional study included 30 imported meat samples, comprising chicken, beef, lamb, and processed meat, randomly collected from various commercial markets in Tripoli, Libya between February 1st and May 15th, 2025. The meat products originated from Brazil, the United States, Jordan, Spain, and Australia. The analysis was conducted at the Center for Food and Drug Control. The collected meat types included: Boneless frozen beef (various cuts such as rib, neck, shoulder, chest), whole boneless frozen beef, frozen chicken without giblets (various cuts), chicken thighs and quarters, chicken products like zinger, crispy fillet, cordon bleu, nuggets, Bone-in frozen lamb (shoulder), and whole boneless frozen lamb. For safety assessment, the concentrations were compared to the permissible limits established by Libyan and European standards for Pb, Cd, and Cr. As for Cu, due to the lack of a specific Libyan maximum allowable limit, the reference value of 1.0 mg/kg was adopted based on previous studies [10]. This is justified by the fact that Cu is an essential trace element for the human body, and its health effects are usually evaluated based on daily intake levels rather than its concentration in food [11]. Sample preparation and analysis: Among the various available methods for detecting heavy metals in meat, this study utilized Atomic Absorption Spectrophotometry (AAS) for both quantitative and qualitative analysis. This technique measures the specific wavelengths of photons emitted by atoms, with each element emitting a unique set of wavelengths. By analyzing these wavelengths, the elements present in the sample can be identified and measured. Before analysis, samples were mechanically homogenized. 1.0 g of the dried sample was weighed and placed in a digestion flask. To each sample, 10.0 mL of concentrated nitric acid (HNO₃) was added and gently heated until the solution became clear. If necessary, a few drops of perchloric acid (HC₁O₄) or hydrogen peroxide (H₂O₂) were added during heating to complete digestion. After digestion and cooling, the solution was diluted to 50.0 mL using high-purity distilled water. The resulting solution was filtered appropriately to remove any solid particles and was then ready for metal absorption measurement using the AAS method. Reagents and instrument calibration: High-grade analytical reagents were used in this study, including deionized water (Millipore), concentrated nitric acid (65.0%), diluted nitric acid (0.1 M), concentrated perchloric acid (used when needed), and hydrogen peroxide (30.0%). Standard solutions (1000 mg/L) for Pb, Cd, Cu, and Cr were prepared by dissolving 1.000 g of pure metal in distilled nitric acid and diluting to 1.0 L. These stock solutions were used to prepare working standard solutions of known concentrations (in mcg/mL) using diluted nitric acid (0.1 M) for calibration purposes. No ethical approval is needed for this study; however, an initial approval was obtained from the committee of Rowad Alelm University, Tripoli, Libya (RAU, 0001-2025). Statistical analysis: Statistical analysis was conducted using SPSS version 26. One-way ANOVA was used to assess the relationship between heavy metal concentrations (Pb, Cd, Cr, and Cu) and meat type, cut, and origin. The level was determined at p<0.05 to be considered statistically significant. Results Table 1 shows different range levels of the heavy metals according to the Libyan standards. Indeed, all the values of Cd and Cr are well below the Libyan permissible limits. However, only Pb exceeds the Libyan limit of 0.05 mg/kg in one sample (max=0.2570 mg/kg). On the other hand, Cu, although not regulated under the Libyan standards, was assessed using a reference value of 1.0 mg/kg and was found to be within safe limits in all samples. Figure 1 shows that chicken samples made up half of the total samples, while beef and lamb samples were nearly evenly distributed (about 1/4 each). Mediterranean Journal of ISSN: 2789-1895 https://mrj.org.ly Medical Research Mediterr J Med Res Altalibet al. Mediterr J Med Res. 2025; 2(4): 276-282. Page 278 Table 1: Mean, standard deviation, minimum, and maximum values of heavy metals Heavy metal Mean (mg/kg) Std. deviation Minimum Maximum Libyan Standard Limit (mg/kg) Lead (Pb) 0.0145 0.0480 0.0020 0.2570 0.10 Cadmium (Cd) 0.0017 0.0003 0.0010 0.0023 0.05 Chromium (Cr) 0.0244 0.0204 0.0090 0.0830 1.00 Copper (Cu) 0.5142 0.2660 0.1187 0.9233 Not specified Figure 1: The percentage of the sample type Figure 2 shows a wide variety of chicken products (47.0%). Cuts were chosen to represent the typical frozen meat products available commercially. Lamb was represented 33%, and Boneless beef was 17.0%, while 3.0% of whole boneless beef. Figure 2: Different percentages of sample cuts Figure 3 shows the origin of the samples in the Libyan market. Brazil was the largest exporter among the sampled products and the remaining countries had almost equal representation. Figure 3: Frequency by country of origin beef 27% lamb 23% chicken 50% 17%3% 47% 33% Boneless Beef (Various Cuts: Rib, Neck, etc.) Whole boneless beef Chicken (cuts, fillet, zinger, cordon bleu...) Lamb (bone-in, full, shoulder) Brazil USA Jordan Spain Australia Mediterranean Journal of ISSN: 2789-1895 https://mrj.org.ly Medical Research Mediterr J Med Res Altalibet al. Mediterr J Med Res. 2025; 2(4): 276-282. Page 279 Table 2 shows that one sample (3.3%) had a Pd level exceeding the Libyan safe limit of 0.05 mg/kg and the remaining samples are within the limit. All the samples had Cd concentrations safely below the maximum permissible level (Table 3). Cr concentrations were well below safety thresholds in all samples (Table 4). Cu levels in all samples were below the reference safety level of 1.0 mg/kg (Table 5). Table 2: Lead concentration levels Lead level Frequency Percent Below normal (<0.10) 29 96.7 Normal (=0.10) 0 0.0 Above normal (>0.10) 01 3.3 Total 30 100 Table 3: Cadmium concentration levels Cadmium level Frequency Percent Below normal (<0.05) 30 100 Normal (=0.05) 0 0.0 Above normal (>0.05) 0 0.0 Total 30 100 Table 4: Chromium concentration levels Chromium level Frequency Percent Below normal (<1.0) 30 100 Normal (=1.0) 0 0.0 Above normal (>1.0) 0 0.0 Total 30 100 Table 5: Copper concentration levels Copper level Frequency Percent Below 1.0 mg/kg 30 100 Equal to 1.0 mg/kg 0 0.0 Above 1.0 mg/kg 0 0.0 Total 30 100 As shown in Table 6, the chicken samples showed the highest Pd and Cd levels in this study, though still within the safe limits according to the Libyan Standards. Moreover, the beef samples had the highest Cr and Cu concentrations. Table 7 shows that Jordan samples had significantly higher Pd concentrations with a mean of 0.07446 mg/kg. The USA samples had the highest Cd average. Cr was highest in high concentrations of Australian samples. Cu was most elevated in the Spanish samples. Table 8 illustrates that Cu concentration varied significantly by meat type. Therefore, no significant difference in the metal concentrations based on the part of the meat sampled in the current study. Additionally, no significant differences in metal levels across different countries of origin. Table 6: Heavy metal average levels by meat type Meat Lead Cadmium Chromium Copper Beef 0.0025 0.00176 0.0280 0.7541 Lamb 0.00212 0.00151 0.0249 0.6728 Chicken 0.02667 0.00184 0.02237 0.31224 Mediterranean Journal of ISSN: 2789-1895 https://mrj.org.ly Medical Research Mediterr J Med Res Altalibet al. Mediterr J Med Res. 2025; 2(4): 276-282. Page 280 Table 7: Heavy metal average levels by country of origin Country Lead Cadmium Chromium Copper Brazil 0.00289 0.00182 0.0249 0.5835 USA 0.0027 0.001867 0.0265 0.2197 Jordan 0.07446 0.00182 0.01533 0.4500 Spain 0.00218 0.00132 0.02506 0.7360 Australia 0.002 0.001813 0.030067 0.51266 Table 8: Relationship between meat type and metal concentrations Metal P-value of Meat type P-value of Meat cut P-value of Country of origin Lead 0.217 0.771 0.795 Cadmium 0.297 0.123 0.165 Chromium 0.535 0.934 0.821 Copper 0.000 0.978 0.596 Discussion A total of 30 samples representing 16 types of imported and processed meat products (beef, lamb, and poultry) were collected from several retail outlets in Tripoli. This sampling approach was similar to a study conducted in the Eastern Province of Egypt [12], where 30 meat samples (15 chilled and 15 frozen) were collected from local markets and analyzed for heavy metal contamination. Comparable studies were also carried out in Libya, including one conducted in Al-Marj City [13], which aimed to assess the levels of heavy metals in imported processed meat products. The results of the current study indicated that all meat samples analyzed fell within the safe limits for heavy metal concentrations according to Libyan specifications, a finding consistent with a study conducted in Kazakhstan [14]. That study concluded that both local and imported poultry meats available on the market were safe for consumption. On the contrary, results diverged significantly from those found in a Nigerian [10], which reported that levels of Pd, Cu, and iron in processed meat exceeded the safety limits set by the World Health Organization. For example, Pd levels reached 1.018 mg/kg, far above the permissible limit of 0.05 mg/kg, suggesting potential health risks. In the current study, Cu had the highest mean concentration among all analyzed metals, ranging from 0.1187 to 0.9233 mg/kg, but remained within acceptable reference levels. Unlike Pd and Cd, Cu typically does not have a fixed maximum limit in most local or international standards (e.g., Libyan standards or WHO guidance), because Cu is an essential nutrient. The estimated average daily intake required by adults is 2-3 mg/day, and Cu toxicity usually depends on total daily exposure rather than its concentration in individual food products. The WHO has proposed a tolerable daily intake of 0.5 mg/kg body weight/day for Cu [8]. By comparison, the Nigerian study reported a Cu level of 1.445 mg/kg, which exceeds the values recorded in the present study. Similarly high levels were observed in a study conducted in Qalyubia, Egypt [15], where Cu levels reached 2.17 mg/kg in poultry meat, suggesting that contamination may originate from product components such as meat, additives, or spices. Regarding Cd, our study revealed moderate concentrations across 100% of the samples. However, it is important to note that the AAS used in this analysis cannot differentiate between Cr forms, Cr (III) and Cr (VI). Only total Cr is measured. Cr (III) is generally non-toxic and essential, while Cr (VI) is highly toxic and carcinogenic. For this reason, advanced analytical methods (e.g., chromatographic separation coupled with mass spectrometry) are recommended to determine the proportion of Cr (VI) [16]. The Cr concentrations observed in this study ranged between 0.0090 and 0.0830 mg/kg, remaining safely below the Libyan standard. These findings differed from the Libyan study in Al-Marj [13], which reported Cr levels ranging from 0.136 to 0.811 mg/L, exceeding WHO and Codex limits. For Pd, the minimum and maximum values ranged from 0.0020 to 0.2570 mg/kg, and one sample exceeded the Libyan limit. In contrast, Mohamed and others [9] in Mediterranean Journal of ISSN: 2789-1895 https://mrj.org.ly Medical Research Mediterr J Med Res Altalibet al. Mediterr J Med Res. 2025; 2(4): 276-282. Page 281 Egypt found Pd levels as high as 0.89 mg/kg, with 66.6% of the samples exceeding permissible limits. These results are similar to those in a Lebanese study [17], which found that 61.0% of canned meat samples had Pd concentrations ranging from 0.2 to 816.1 µg/kg, suggesting that canned meats may contain higher heavy metal concentrations than other meat types. As for Cd, its concentrations ranged between 0.0010 and 0.0023 mg/kg, and 100% of samples were within safe limits. These results agree with findings in Astana, Kazakhstan [14], which reported Cd levels between 0.51 and 0.65 µg/kg, considered safe for consumption. However, they contradicted the results in Assiut, Egypt [18], where Cd levels ranged from 0.01 to 0.382 mg/kg, and 60.0% of pastrami and 36.67% of luncheon meat samples exceeded safe limits. The statistical analysis in the current study revealed no significant relationship between the type of meat (chicken, beef, or lamb) and the concentrations of Pd, Cd, or Cr, suggesting that these metals are evenly distributed across meat types. These results differed from a study in Erbil, Iraq [19], which found significant variations in heavy metal concentrations among beef, lamb, and buffalo meat. However, a highly significant relationship was observed between meat type and Cu concentration, indicating that Cu levels are influenced by the type of meat. This supports findings in Egypt [15], where significant variation in Cu levels was linked to poultry processing methods and ingredients. There was no significant relationship between the concentration of any of the four metals (Pd, Cd, Cu, Cr) and the meat part (e.g., shoulder, thigh, breast). These findings contradict those in Sebha, Libya [20], who found that Cu levels in chicken bones were significantly higher than in flesh or skin. Likewise, the current results showed no significant association between metal concentrations and country of origin, indicating that differences between exporting countries did not influence contamination levels. This matches the previous findings [14], who found no significant differences in the metal content of poultry meat from various countries. On the other hand, a global meta-analysis reported regional variation in contamination levels, particularly elevated Pd and Cd levels in red meat from Asia and Africa, often exceeding international safety limits [9]. This suggests that the country of origin may play a significant role in contamination risk, especially in countries with poor environmental and food safety regulations. Conclusion: This study focused on evaluating the contamination levels of heavy metals in imported red meat and poultry products available in Tripoli markets. Although the findings suggest that most samples are within safe limits, there remains an urgent need for enhanced regulation and stricter monitoring of the quality of imported meat, both red and white types. Importing companies must adopt more rigorous quality assurance procedures to ensure that their products are free from hazardous heavy metals and safe for consumption. References 1. Pereira PM, Vicente AF. Meat nutritional composition and nutritive role in the human diet. Meat Science. 2013; 93(3): 586-592. doi: 10.1016/j.meatsci.2012.09.018 2. 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Conflict of interest: The authors declare the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Ethical issues: The authors completely observed ethical issues including plagiarism, informed consent, data fabrication or falsification, and double publication or submission. Data availability statement: The raw data that support the findings of this article are available from the corresponding author upon reasonable request. Author declarations: The authors confirm that they have followed all relevant ethical guidelines and obtained any necessary IRB and/or ethics committee approvals. Generative AI disclosure: No generative AI was used in the preparation of this manuscript.