Human health risk assessment of some important trace elements in boneless whole chicken meat

Sample collection

The sampling period was completed in June 2021. A total of 30 random samples of boneless whole chicken were purchased from various shops in Amman, Jordan, and immediately dried in an oven at the selected temperature. The trace element content of each chicken sample was expressed in milligrams per kilogram of dry weight.

Materials

A purification water system from Millipore was used to deionize water. Nitric acid 70% was bought from Biosolve chemical company (Valkenswaard, Netherlands), and multielement standard calibration solution 1000 mg/L was obtained from Accustandard supplies (New Haven, USA). All glassware used in this study was decontaminated overnight with 10% HNO₃ and rinsed with purified water.

Sample preparation

Whole boneless chicken samples were dried in oven at 105 °C until a consistent weight was achieved. Following that, one gram of each dry sample was placed in a pressure-resistant Teflon (PTFE-TFM) flask and digested with Milestone ETHOS 1 microwave oven (Sorisole, Italy) in accordance with the food safety and standards authority of India (FSSAI) (FSSAI, 2016) with modifications on the digestion protocol which includes the temperature, the time, and the microwave power. For each chicken sample, 7 ml of HNO₃ and 1 ml of H₂O₂ were introduced into separate flask. The flask was capped tightly then heated following the microwave digestion protocol: 1800 W at 180°C (ramp time 15 minutes, holding time 15 minutes, and cooling time 15 minutes). After cooling, all digested combinations were filtered and diluted to 100 mL with distilled water.

Analysis of digested chicken samples

A Thermo Fisher Scientific iCAP 7400 ICPOES Due was used in combination with a Burgener mira mist atomizer and a glass cyclone chamber to detect trace elements in digested chicken samples. For optimal operating conditions, the ICPO-ES was tuned to a radio frequency (RF) power of 1150 W, nebulizer gas flow at 0.5 L/min, cooling gas flow at 14.5 L/min, and auxiliary gas flow at 0.5 L/min. Each digested sample was tested three times.

Validation of analytical method

Percent recovery, linearity, limit of quantitation (LOQ), limit of detection (LOD), and precision are validation parameters for the analytical method, as shown in Table 1. The validation of the method was carried out in accordance with the International Conference on Harmonization (ICH) guidelines (ICH, 1996). Furthermore, a certified reference material (CRM) was used to validate the current study's analytical approach (Animal Origin Reference Material). After being treated to a microwave acid digestion, the CRM was tested with ICP-OES in the same way as actual chicken samples.

Risk assessment

Risk scores for the current study were calculated by examining chicken samples to determine daily intake (EDI), risk ratio (THQ), and carcinogenic risk (CR).

Estimated daily intake (EDI)

Ingestion is a common way humans are exposed to trace elements. The daily intake (EDI) of trace elements for adults eating boneless chicken was calculated using the following equation (Alipour and Banagar, 2018):

where Cm is the metal concentration in mg/kg dry weight in boneless chickens. EF - frequency of exposure (365 days/year). FIR - Chicken consumption rate (for adults, 0.085 kg/(person × day); ED is the duration of exposure (60 years). Assume an average adult body weight (BW) of 79 kg and TA is the mean time to non-carcinogenic substances (365 days/year × ED) (Saha et al., 2016). When calculating health risks, it was assumed that the swallowed pollutant quantity is equivalent to the absorbed contaminant amount (USEPA, 1989) and that cooking had no influence on contaminant concentrations (Cooper et al., 1991). The exposure parameters considered in risk estimations are listed in Table 2 (USEAP, 2012).

Target hazard quotient (THQ)

The non-carcinogenic risk to the population from consuming contaminated chicken was calculated using the target hazard quotient (THQ). THQ was calculated by dividing the estimated daily intake (EDI) of trace elements in polluted boneless chicken by the reference oral dose (RfD) for each element (Mortazavi and Fard, 2017). When THQ is less than 1, trace elements is less likely to have serious health effects. A THQ greater than 1 increases the likelihood that this trace element is hazardous to health (USEAP, 2012). THQ was calculated using the following formula:

Carcinogenic risk (CR)

The CR is a measure of the likelihood of developing any type of cancer as a result of lifetime exposure to carcinogenic elements. Using the cancer slope factor, the CR over a lifetime of exposure was predicted using the following equation (Peng et al., 2016; Shaheen et al., 2016):

where CSF denotes the cancer slope factor (mg/kg/day), and the rest of parameters have already been described. An acceptable lifetime carcinogenic risk of 10⁻⁵ has been established by USEPA (Saha et al., 2016).

Statistical analysis

Microsoft Excel software was used in performing all statistical analysis. Descriptive statistics include the arithmetic mean (AM), percentile (P), standard deviation (SD), and range (min-max). Pearson's correlation coefficient analysis (PCA) can be applied to the measurement data to determine the source of trace elements quantified by ICP-OES. PCA calculates the strength of association between two variables on a scale of -1 (perfect inverse relation) to +1 (perfect sympathetic relation) (Adebiyi et al., 2020). If two variables have a strong relationship, they may be derived from the same parent.

Concentrations of trace elements in boneless chicken meat

The central limit theorem (CLT) was used to determine the sample size (n = 30) (Mascha and Vetter, 2018; Brussolo, 2018; Kwak and Kim, 2017). ICP-OES was used to test boneless chicken samples for Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn. Table 3 displays some basic statistics for trace element concentrations in boneless chicken samples. The mean concentrations of Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn were 8.77, 0.29, 0.013, 0.77, 1.37, 23.44, 0.0005, 3.74, 0.063, and 28.22 mg/kg, as shown in Table 3. Concentrations of trace elements in boneless chicken samples decreased in the following order: Zn > Fe > Al > Mn > Cu > Cr > As > Pb > Cd > Hg. The concentrations of Al, As, Cd, Cr, Cu, Fe, Mn, Pb, and Zn in boneless chicken samples ranged from 2.25 to 25.52 mg/kg, from 0.142 to 0.419 mg/kg, from 0.006 to 0.024 mg/kg, from 0.524 to 1.089 mg/kg, from 0.943 to 2.316 mg/kg, from 15.629 to 44.48 mg/kg, from 1.532 to 6.473 mg/kg, from 0.003 to 1.69 mg/kg, from 19.51 to 43.33 mg/kg, respectively. On the other hand, the concentration of Hg in all investigated chicken samples was below the limit of detection (<0.0005 mg/kg).

According to Table 4, the mean As concentration in this study (0.29 mg/kg) was approximately three times higher than the maximum allowable As limits in chicken reported by FAO/WHO and WHO guidelines. This concentration was lower than that reported by Dionísio et al. (2010), who found that the concentration range of As determined in chicken production-related samples ranged from 1.30 to 29.8 mg/kg.

Cd is a non-essential element that is not present at birth (Thabetelsharawy et al., 2019). The mean Cd content in the current study was lower than that reported by Thabetelsharawy et al. (2019), which was 0.056 mg/kg (Table 5). The mean Cd content in this study was below the MHPRC, EC, and FAO/WHO standards of 0.1, 0.05, and 0.05 mg/kg, respectively, as shown in Table 4.

Cu is involved in blood formation as well as glucose and lipid metabolism (Kwon and Lee, 2001). The mean Cu content in this study was seven times higher than the values published by Thabetelsharawy et al. (2019), but equivalent to the concentration reported by Zhuang et al. (2014) (Table 5). The mean Cu content in this study surpassed the WHO, EC, and FAO/WHO standards of 0.4, 1, and 1 mg/kg, respectively, as shown in Table 4.

Hg is a harmful trace element that enters the body through the intake of fish (Jaishankar et al., 2014). The type, amount, and frequency of exposure to Hg all contribute to human toxicity. Hg salts mostly harm the renal and intestinal walls, whereas elemental mercury vapour causes severe pneumonitis (Kalay, 1999). Hg is toxic to the human nervous system, and there is evidence of a link between fetal Hg exposure and neurodevelopment in children (Kimáková et al., 2018). In this study, the Hg content (0.0005 mg/kg) did not exceed the maximum EC limit for chickens of approximately 1.0 mg/kg (Mathaiyan et al. 2021). According to Mathaiyan et al. (2021), Hg concentrations ranged from 0.0477 to 0.5457 mg/kg (Table 5).

Zn promotes wound healing, lipid and glucose metabolism, hormonal function and hair growth (Topcuoglu et al., 2002). As shown in Table 4, the average Zn concentration (28.22 mg/kg) in this study exceeded the maximum permissible limit for Zn in chicken meat stipulated by FAO/WHO and EU, but did not exceed the maximum limit stipulated by the People's Republic of China’s Ministry of Health of China (MHPRC). According to Table 5, the average Zn concentration in this study (28.22 mg/kg) is lower than the corresponding average concentration reported by Zhuang et al. (2014).

Pb has been linked to delayed development, lower IQ, decreased attention span, hyperactivity, and mental deterioration in children. Memory loss, nausea, insomnia, anorexia, joint weakness, brain, nervous system, red blood cells, and kidney damage in adults (Wuana and Okieimen, 2011). As shown in Table 4, the mean Pb concentration in this study (0.063 mg/kg) was lower than the maximum allowable Pb limits in chicken reported by FAO/WHO, the European Commission, and the People's Republic of China's Ministry of Health (MHPRC). Mean Pb concentrations were found to be lower in the current study than the data of 0.30 mg/kg and 0.52 mg/kg reported by Thabetelsharawy et al. (2019) and Zhuang et al. (2014), respectively.

Cr has shown to produce skin irritation and ulceration in humans after acute exposure, as well as kidney and liver malfunctions, circulatory and nervous system damage (Wuana and Okieimen, 2011). According to Table 4, the mean Cr concentration was less than the USEPA's concentration threshold (1.0 mg/kg) (Mottalib et al. 2018). The mean Cr concentration in this study was 0.77 mg/kg, which was lower than the value found by Mottalib et al. (2018) in broiler chicken (3.98 mg/kg).

The mean Mn concentration in this study was 3.74 mg/kg, which was lower than the value reported by Korish and Attia (2020).

Pearson’s correlation coefficient analysis (PCA)

Table 6 shows the results of PCA analysis of trace elements tested in boneless chicken samples. A positive correlation was found between As/Pb, Pb/Fe, Cd/Cr and Cu/Cr in PCA analysis. A positive relationship indicates that the elements in the sample have a similar genetic origin, chemical affinity, and/or a common background level, while a negative relationship indicates that the elements are not chemically similar or originate from different sources.

Health risk assessment

Estimated daily intake (EDI) and target hazard quotient (THQ)

Table 7 summarizes the oral reference doses (RfD) of the trace elements studied in this study. The estimated daily intake (EDI) of Al, As, Cd, Cr, Cu, Fe, Mn, Hg, Pb, and Zn in adults is 9.4 × 10⁻³, 3.12 × 10⁻⁴, 1.40 × 10⁻⁵, 8.3 × 10⁻⁴, 1.5 × 10⁻³, 4.59 × 10⁻², 4.0 × 10⁻³, 5.38 × 10⁻⁷, 6.78 × 10⁻⁵, and 3.0 × 10⁻² , respectively. Except for Al and As, the EDI values of the investigated elements were lower than their corresponding RfD values. Table 7 shows that the calculated THQ of the trace elements (Al and As) was greater than 1, indicating that Jordanians have a potential health risk if they eat boneless chicken containing these elements.

Cancer risk (CR)

The current study found that the CR factors for As, Cd, Cr, and Pb during a lifetime consumption of contaminated fish were 4.68 × 10⁻⁴, 8.81 × 10⁻⁵, 4.14 × 10⁻⁴, and 5.76 × 10⁻⁷ , respectively (Table 7). The United States Environmental Protection Agency has set an acceptable limit for a lifetime cancer risk of 10⁻⁵ (Saha et al., 2016). The CR of As, Cd, and Cr in this study were higher than the USEPA acceptable value, indicating that people who eat boneless chicken are at a higher risk of developing cancer.

Conclusion and recommendation

Concentrations of ten trace elements (Zn > Fe > Al > Mn > Cu > Cr > As > Pb > Cd > Hg) in boneless whole chicken samples collected from various Jordanian markets were determined using ICP-OES in the present study. Zn has the highest average concentration of trace elements in chicken samples, while Hg has the lowest. Health risk assessment of ten trace elements was investigated for a Jordanian population. As a result, toxic elements were ranked in the order of Al > As > Cr > Zn > Cu > Fe > Mn > Pb > Cd > Hg based on the THQ index, highlighting that the total THQ of all trace elements was greater than one. Furthermore, the CRs of As, Cd, Cr, and Pb were 4.68 × 10⁻⁴, 8.81 × 10⁻⁵, 4.14 × 10⁻⁴, and 5.76 × 10⁻⁷, respectively. It can be concluded that exposure to As, Cd and Cr may pose a threat to human health. These metals can accumulate to harmful levels, so JFDA is required to monitor trace elements levels in chicken products commonly consumed in Jordan. In addition, the results of this research shed the light that ICP-OES is a suitable and rapid technique for the determination of trace element concentrations when applied in food industry. Nevertheless, the exposure of these trace elements from many other food sources has not been taken into account in this assessment, which could contribute to the exposure from chicken consumption.

Underlying data

Open Science Framework: Human health risk assessment of some important trace elements in boneless whole chicken meat, https://doi.org/10.17605/OSF.IO/C6VAB (Al-Subeihi, 2022).

This project contains the following underlying data:

Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).