Open Veterinary Journal, (2024), Vol. 14(1): 266-273

Original Research

10.5455/OVJ.2024.v14.i1.23

Risk assessment of some toxic metals in canned fish products retailed in Mansoura, Egypt

Mohamed A. Hussein¹, Samar E. Morgan¹, Abdallah F. Mahmoud¹ and Waleed R. El-Ghareeb^1,2*

¹Food Hygiene, Safety and Technology Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt

²Department of Public Health, College of Veterinary Medicine, King Faisal University, Al Hofuf, Saudi Arabia

*Corresponding Author: Waleed R. El-Ghareeb. Department of Public Health, College of Veterinary Medicine, King Faisal University, Al Hofuf, Saudi Arabia. Email: welsaid [at] kfu.edu.sa

Submitted: 01/10/2023 Accepted: 15/12/2023 Published: 31/01/2024

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ABSTRACT

Background: Canned fish products are widely consumed in Egypt, particularly for protein-rich meals that are quick to prepare and low in calories. Canned fish products are contaminated with toxic metals from the fish itself or from canning materials during processing.

Aim: To determine the residual levels of cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), aluminum (Al), and Tin (Sn) in some canned fish products obtained from retail shops in Mansoura, Egypt. Furthermore, noncarcinogenic health risks evaluation for the Egyptian population due to hazardous metal oral intake.

Methods: One hundred canned fish products (20 each of herring, mackerel, salmon, sardine, and tuna) were collected from May to September 2023, and canned fish products were obtained from Mansoura city markets in Egypt. Samples were digested in a solution composed of 60% nitric acid and 40% perchloric acid, and then an atomic absorption spectrophotometer was used for the detection of selected toxic metals.

Results: It was found that the residual level of hazardous metals exceeded the acceptability level established in the European Union for Pb, Cd, and Hg by 20%, 10%, and 10%, 15%, 5%, and 20%, 35%, 30%, and 45%, 25%, 25%, and 40%, in examined herring, mackerel, sardine, and tuna, respectively. In contrast, all salmon samples were accepted for Pb and Hg, and only 5% were not accepted due to a higher Cd level than the maximum permissible limit. The average estimated daily intake of (EDI) is below the tolerable daily intakes (TDIs) for all metals. Comparatively, the EDI of Hg was 0.265 µg/kg body weight (B.W) exceeded TDIs 0.228 µg/kg B.W. The hazard index for canned tuna and sardines is more than one.

Conclusion: Canned fish products are contaminated with a variety of toxic metals, especially sardine and tuna. Therefore, it is advised to decrease the consumption rate of such fish products.

Keywords: Toxic metals, Canned fish, Risk.

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Introduction

Fish can provide more than 50% of high-quality protein, minimal fat, polyunsaturated essential fatty acids, and micro and macronutrients. World population growth has exceeded fish production due to the increased consumption rate, which has grown per capita globally since 2017 (World Data Statistics, 2017). In Egypt, while addressing the issue of red meat scarcity, fish offers consumers low prices of high biological value animal protein (Ahmed et al., 2013; Hussein et al., 2019). Dietary intakes and risk evaluation of biogenic amine accumulation in fish were studied (El-Ghareeb et al., 2021). Despite the high nutritional value of fish, over eating seafood products can have detrimental health effects on consumers due to heavy metal accumulation in fish muscles from the water in which reared (Castro-González and Méndez-Armenta, 2008). Heavy metals are a major contaminant of the aquatic environment due to their high levels of persistence in the ecosystem and toxicity to marine animals. Human exposure to hazardous metals has increased dramatically over the last 50 years due to an exponential increase in the use of heavy metals in industrial processes and products (Fu and Xi, 2020). According to Sarmiento et al. (2011), even very low metal concentrations can be harmful to the health of terrestrial and aquatic creatures, including people. Depending on the stage of development, age, and other physiological parameters, the distribution of metals varies amongst fish species. Fish can be a significant dietary source of mercury for humans since they have high quantities of the element in their tissues. The major source of mercury and arsenic for people is fish. Humans are known to be toxic to mercury, and eating fish is one of the main ways that people get mercury exposure. A hazardous issue for human health is the biotransformation of mercury and the creation of methyl mercury (Khansari et al., 2005). In Egypt, the fish canning business has grown significantly, and locally made canned fish items are sold widely in Egyptian markets. The fish canning process varies depending on the product being canned, and the size, and shape of the container, but there are generally a few basic steps that are followed, the most important of which is selecting and preparing raw materials for processing to produce a product that meets quality control standards. Industrialization has improved life quality and general technology, but it has also increased metal concentrations in water (Morshdy et al., 2013). The current investigation attempted to determine the residual level of a hazardous metal in canned fish products obtained from retail shops in Mansoura, Egypt. Furthermore, noncarcinogenic health risk evaluation for the Egyptian population due to hazardous metal oral intake.

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Materials and Methods

Sample collection

One hundred canned fish products (20 each of herring, mackerel, salmon, sardine, and tuna) were collected from May to September 2023, canned fish products obtained from Mansoura city fish market in Egypt. Canned fish products were picked from cans that appeared to be normal, with no signs of exterior or internal spoilage.

Sample preparation

Sample preparation was according to Finerty et al. (1990) briefly; 1 g of flesh is obtained by using a sterile can opener, and then homogenized for 12 hours in 5 ml of (60% nitric acid and 40% perchloric acid) as digestion solution. The solution was then warmed for 3 hours at 70°C in a water bath while being stirred every 30 minutes. After being diluted with 20 ml of double distilled water and kept at 20°C, the filter paper was used in the filtration of the digested mixture and kept until the determination of toxic metals.

Analysis of metals

Lead, cadmium, aluminum, and tin were detected with Perkin Elmer atomic absorption spectrophotometer (AAS) PinAAcleTM 900T. While arsenic and mercury were analyzed by hydride generation/cold vapor (AAS).

Quality control

DORM-3 fish obtained from (NRC) were used to ensure the accuracy of the processes. The limit of detection (µg/g) for “lead, cadmium, arsenic, mercury, aluminum, and tin were 0.01, 0.005, 0.02, 0.01, 0.1, and 0.02 for each element.” The metal levels detected were indicated in [µg/g wet weight (WW)].

Estimated daily intake (EDI)

The US EPA (2017) stated that EDI (µg/kg/day)=C^m × F_IR/body weight (B.W) was used to compute the EDI of different metals that consumers intake through ingestion of fish products, where Cm is the mean of the examined element (µg/g WW)”. In addition, FAO (2010) stated, “food ingestion rate per capita for adults set at 48.57 g.” B.W in adult Egyptian is fixed at 70 kg.

Health risk assessment

According to US EPA (2010), the (HQ) of the analyzed metals was calculated “HQ=EDI/RFD × 10⁻³. For lead, cadmium, arsenic, mercury, aluminum, and tin the RFD is 0.004, 0.001, 0.0003, 0.0005, 1, and 0.0003 mg/kg/day.” The US EPA (2017) stated the following equation for Hazard index (HI) to quantify the danger of combined metals HI=target hazard quotient (THQ) of (lead + cadmium + arsenic + mercury + aluminum + tin).

Statistical analysis

The statistical analysis was assessed using ANOVA the post-hoc test and the Turkey. Significant data was defined as a p-value of 0.05. The data (SD) were expressed using the means and standard deviation (SAS, 2008).

Ethical approval

Not needed for this study.

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Results

The obtained values in Figure 1 cleared that Pb residues were detected in all canned fish products. The canned sardine samples had significantly higher Pb residue 0.477 ± 0.11 mg/kg, than canned mackerel (0.341 ± 0.09 mg/kg), canned tuna (0.307 ± 0.10 mg/kg), canned herring (0.227 ± 0.09 mg/kg), and canned salmon (0.083 ± 0.02 mg/kg).

The cadmium was 0.050 ± 0.008 mg/kg WW in canned sardine had significantly (p < 0.05) higher Cd residues. Meanwhile, canned herring contained significantly (p < 0.05) lower Cd (0.007 ± 0.002 mg/kg WW) as shown in Figure 2.

All examined canned fish products contained As with mean values 1.39 ± 0.20, 0.702 ± 0.03, 0.85 ± 0.09, 1.14 ± 0.03, and 0.77 ± 0.12 in canned herring, mackerel, salmon, sardine, and tuna, respectively (Fig. 3).

The Hg residue was significantly lower (p < 0.05) in canned salmon 0.033 ± 0.004, mg/kg. The ascending Hg level belongs to canned herring, then canned mackerel, then canned tuna, and finally canned sardine 0.203 ± 0.03, 0.343 ± 0.05, 0.653 ± 0.04, and 0.673 ± 0.07 mg/kg, respectively (Fig. 4).

The mean values of Al residues were 1.797 ± 0.28, 1.707 ± 0.34, 2.73 ± 0.31, 3.22 ± 0.43, and 2.097 ± 0.28 mg/kg in canned herring, mackerel, salmon, sardine, and tuna, respectively (Fig. 5).

The Sn residues were 0.069 ± 0.004, 0.095 ± 0.005, 0.080 ± 0.003, 0.081 ± 0.004, and 0.079 ± 0.003 mg/kg in canned herring, mackerel, salmon, sardine, and tuna, respectively (Fig. 6).

When the satisfactoriness of the tested samples was compared to the acceptability of EC, it was distinct that four (20%), three (15%), seven (35%), and five (25%), of the canned herring, mackerel, sardine, and tuna, respectively, more than the maximum permissible limit (MPL) (0.3 mg/kg ww) for lead in fish on comparing with European Commission’s (2006). Meanwhile, two (10%), one (5%), two (10%), six (30%), and five (25%), respectively, of the canned herring, mackerel, salmon, sardine, and tuna exceeded the Cd residue limit (0.05 mg/kg ww). Meanwhile, two (10%), three (15%), nine (45%), and eight (40%), respectively, of the canned herring, mackerel, sardine, and tuna exceeded the European Commission’s (2006) MPL of 0.5 mg/kg ww. as shown in Table 1.

Fig. 1. Lead mean values (mg/kg ww) in canned fish products. Different little letter columns are significant.

Fig. 2. Cadmium mean values (mg/kg ww) in canned fish products. Different little letter columns are significant.

Fig. 3. Arsenic mean values (mg/kg ww) in canned fish products. Different little letter columns are significant.

Fig. 4. Mercury mean values (mg/kg ww) in canned fish products. Different little letter columns are significant.

Fig. 5. Aluminium mean values (mg/kg ww) in canned fish products. Different little letter columns are significant.

Fig. 6. Tin mean values (mg/kg ww) in canned fish products. Different little letter columns are significant.

Table 2 shows that the EDI of toxic metals from canned fish product eating was lower than the tolerable daily intake (TDIs) for examined metals except for Hg, which was higher than the adjusted TDI (0.228 µg/kg B.W) as 0.238 from mackerel, 0.467 from sardine, and 0.453 µg/kg B.W from tuna consumption.

The average THQ for tested metals was less than one based on EDI. Meanwhile, calculating the HI based on 10% total arsenic in fish exclusively inorganic all analyzed canned fish products below one except canned sardine (1.50) and tuna (1.34) (Table 3).

Table 1. The satisfactoriness of the canned fish products according to EC standard.

Table 2. A comparison between the EĐI to TĐIs µg/kg BW.

Table 3. THQ and HI for toxic metals in canned fish products.

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Discussion

Examined toxic metals such as lead, cadmium, arsenic, mercury, aluminum, and tin are known to have no physiological significance. Certain metals can cause organ damage and a variety of toxicological effects when continuously consumed, even in low quantities, due to their capabilities of bioaccumulation and biomagnification (Jaishankar et al., 2014). Lead residues detected in canned fish products worldwide as 0.03 to 8.62 mg/kg WW in China (Leung et al., 2014), 0.03 to 0.51 mg/kg WW in Kingdom Saudia Arabia (Ashraf et al., 2006), 0.16 ± 0.11 mg /kg WW in Italy (Russo et al., 2013), 0.1 0.08 mg/kg WW in Iran (Andayesh et al., 2015), and 0.01 ± 0.005 mg/kg WW in Poland (Kowalska et al., 2020).

The cadmium residues were nearly similar to those previously obtained 0.02–0.06 mg/kg WW in tuna fish from China (Leung et al., 2014), and 0.01–0.06 mg/kg WW in canned tuna retailed in Italy (Russo et al., 2013), and 0.06 ± 0.01mg/kg WW in Poland (Kowalska et al., 2020). Comparatively, lower Cd residues 0.001–0.006 mg/kg WW were detected in Iran (Andayesh et al., 2015). Higher Cd residues of 0.07–0.64 mg/kg WW were reported in canned fish marketed in the KSA (Ashraf et al., 2006). Lower levels of As residues were detected from 0.03 to 1.53 mg/kg WW in China (Leung et al., 2014), from 0.25 to 1.42 mg/kg WW in Iran (Andayesh et al., 2015), and from 0.96 ± 0.29 mg/kg WW in Poland (Kowalska et al., 2020). This could be because the technique used in this study detects total arsenic, even though inorganic arsenic concentrations the most hazardous kind are more important to consider when it comes to human food. Still, fish and fish products have very low levels of inorganic arsenic (Molin et al., 2015). The primary chemical forms of arsenic in fish are arsenobetaine and arsenocholine, which are rapidly and unmetabolized eliminated in human urine, and are thought to be nontoxic (Francesconi, 2010).

The mercury values in this study were comparable to Hg in canned fish retailed in Brazil at0.41 mg/kg WW (Morgano et al., 2014). Meanwhile, much lower Hg was detected in Italy at 0.05 ± 0.05 mg/kg WW (Russo et al., 2013), in Iran at 0.06–0.16 mg/kg WW (Andayesh et al., 2015), and in Poland at 0.06 ± 0.009 mg/kg WW (Kowalska et al., 2020). Pregnant women and young kids should exercise extra caution when exposed to mercury since mercury stunts brain development (Sheehan et al., 2014). This study also employed a careful methodology, assuming that mercury in the fish was methylmercury, which is substantially more toxic than metallic mercury, which is frequently detected in fish. Usually, 80%–100% of the total Hg in fish is accounted for by methylmercury (EFSA Panel on Contaminants in the Food Chain, 2012).

The data obtained demonstrate the species differences in the bioaccumulation of toxic metals; for example, salmon had the lowest amounts of various metals, while sardine and tuna had the greatest residual quantities. This may depend on the fish’s place in the food chain because tuna fish, which are predatory fish, collect higher concentrations of heavy metals (Hussein et al., 2023). The high concentrations of lead, mercury, and arsenic in the tested products indicate either the fish’s lifelong exposure to these metals or contamination of the canning materials or post-processing (Morshdy et al., 2021).

Aluminum is the most common metal in nature and, by extension, in food. However, throughout time, anthropogenic actions and soil acidity have led to an increase in Al levels. Al is considered a hazardous material because it accumulates in the brain. Al levels and a number of illnesses, including Alzheimer’s disease, have been linked in numerous studies. In addition, aluminum might interfere with some significant metals (Sjögren et al., 2007). The obtained Al residues were nearly similar to the finding of 4.76 ± 4.37 and 7.22 ± 1.62 mg/kg WW in canned tuna from Lebanon and Egypt (Al Ghoul et al., 2020; Morshdy et al., 2021).

Increased exposure to tin and its constituents has been linked to harmful side effects, including neurological issues, gastrointestinal issues, lung irritation, and ocular irritation (Boogaard et al., 2003). Consuming seafood, juice, or other liquid goods packaged in tin-lined cans exposes humans to tin and its compounds, such as organotin. Unlacquered tin-lined cans, which have a tin content of up to 100 parts per million, are particularly high in tin (Graf, 2000). The obtained tin values in the current study were slightly lower than the Sn values obtained in fish products in Poland 0.12 ± 0.01 mg/kg WW (Kowalska et al., 2020). There were no significant differences (p < 0.05) between examined canned fish products which may attributed to the main is leaching of Sn from the tin-coat into the fish product.

Assessment of health risks

Canned fish products contribute 5.575%, 1.480%, 32.158%, 1.123%, and 0.009% of TDIs from lead, cadmium, arsenic, aluminum, and tin, respectively. Meanwhile, the consumption of canned fish products contributes to 116.049% of TDIs in the case of Hg, which indicates possible hazards according to the suggested TDIs of the World Health Organization (2010).

The total As from fish consumption is not important but, only inorganic chemical forms of arsenic are considered (ATSDR, 2005). In addition, 10% of the As were thought to be inorganic in the worst-case scenario (US EPA, 2002).

The THQ average for lead, cadmium, arsenic, aluminum, and tin is less than 1, indicating that there are no health risks associated with consuming canned fish products. In Lebanon and Egypt, consuming canned fish resulted in almost identical innocuous THQ levels (Al Ghoul et al., 2020; Morshdy et al., 2021). The mixed contaminants HI for salmon (0.453) < herring (0.809) < mackerel (0.927) < tuna (1.341) < sardine (1.504) falls within the average (1.007) in an ascending order. This suggests that consuming too much-canned fish could be harmful to consumers’ health. As a result, it is advised to consume canned fish products in moderation.

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Conclusion

Certain canned fish products contain levels of hazardous metals that are beyond the allowable limits established by regulation by the European Commission. The results were lower than the (TDIs) of the toxic element, which were estimated using the means of lead, cadmium, arsenic, mercury, Al, and Sn in canned fish samples and the mean amount of fish consumed daily by individuals. The THQ is less than one. It is advised to consume canned fish products in moderation, as HI is now higher than one.

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Acknowledgment

None.

Conflict of interest

There is no conflict of interest, according to the authors.

Funding

None.

Data availability

All data are provided in the manuscript.

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