# Comparative Study of the Presence of Heavy Metals in Edible Vegetable Oils
## 2 Analysis of Publications and Trend of Heavy Metals in Edible Vegetable Oils
### Results of the Analysis of Heavy Metals in Edible Vegetable Oils
#### 2.3.2 Lead (Pb)  
Pb can be found in edible vegetable oils as a consequence of environmental contamination, refining processes, transfer during transport, or the packaging process [80]. Furthermore, Pb is a heavy metal that accumulates in the body altering cell metabolism and being a precursor of different harmful effects on human health [20], such as the decrease in the number of erythrocytes necessary for the synthesis of red blood cells and haemoglobin, due to the inhibition of enzymes because of exposure to this heavy metal [84]. Table 2 shows that there are several regulations that establish the maximum limit for the presence of lead in edible vegetable oils at 0.10 mg/kg. These are: _WHO (Codex Alimentarius)_ at the international level, _Commission Regulation (EU) 2021/1317_ at the European level, and _Royal Decrere_ 308/1983 at the Spanish level. Table 4 shows both the results that are close to 0.10 mg/kg and the results that significantly exceed it. The results for sesame oil from Iran are close to the limit with values between 0.092 and 0.099 mg/kg [53]. Most of the results obtained equal or exceed the regulatory limit, such as olive oils from Iran, Italy and Pakistan, with values between 8.546 and 18,783, and 1.321 and 7.249 mg/kg, respectively [51; 81], sunflower oil from the United Kingdom, with 0.274 mg/kg [42], and rapeseed \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Types** & **Analytical** & **Limit of** & **Limit of** & **Results** & **Region** & **Reference** \\
**of Oils** & **Techniques** & **Detection (LD) 1** & **Quantification (LO) 1** & **Average Value 1** & & \\ \hline Rice oil & ICP-MS & 0.50 & - & \textless{LD}–0.891 & USA (Peoria, Illinois) & [31] \\ \hline Rapeseed oil & ICP-OES & - & - & 0.88 & China (Shizhuyuan, Chenzhou) & [80] \\ \hline Sunflower oil & GC-MS-AAS & - & - & \textless{LD}–0.54 & India (Tamil Nadu) & [82] \\ \hline Corn oil & ICP-OES & \(1.00\times 10^{-4}\) & \(2.00\times 10^{-4}\) & 0.02–0.14 & Morocco, Algeria, Jordan & [83] \\ \hline Olive oil & ICP-OES & \(1.00\times 10^{-4}\) & \(2.00\times 10^{-4}\) & \textless{LQ}–0.10 & Morocco, Algeria, Jordan & [83] \\ \hline Olive oil & ICP-MS & - & - & 0.02–0.09 & Cyprus & [60] \\ \hline Olive oil & ICP-OES & - & - & \textless{LD}–1.004 & Iran, Italy & [81] \\ \hline Olive oil & ICP-OES & - & - & 0.396–4.181 & Iran, Italy & [81] \\ \hline Olive oil & FAAS & \(7.40\times 10^{-5}\) & \(2.48\times 10^{-3}\) & 0.026–0.097 & Turkey (Istanbul) & [58] \\ \hline Rapeseed oil & ICP-OES & \(1.00\times 10^{-3}\) & \(3.00\times 10^{-3}\) & 0.098–0.099 & Iran & [53] \\ \hline Corn oil & ICP-OES & \(1.00\times 10^{-3}\) & \(3.00\times 10^{-3}\) & 0.098–0.100 & Iran & [53] \\ \hline Olive oil & ICP-OES & \(1.00\times 10^{-3}\) & \(3.00\times 10^{-3}\) & 0.094–0.097 & Iran & [53] \\ \hline Sesame oil & ICP-OES & \(1.00\times 10^{-3}\) & \(3.00\times 10^{-3}\) & 0.090–0.097 & Iran & [53] \\ \hline Sunflower oil & ICP-OES & \(1.00\times 10^{-3}\) & \(3.00\times 10^{-3}\) & 0.091–0.100 & Iran & [53] \\ \hline Olive oil & ICP-OES & \(3.80\times 10^{-4}\) & \(1.28\times 10^{-3}\) & \(\begin{array}{c}2.24\times\\ 10^{-3}-0.1052\end{array}\) & Turkey (Istanbul) & [50] \\ \hline \hline \end{tabular}  
* The values present the decimal places provided by the authors or, failing that, approximated to three decimal places. 2 Different seasonings added to flavour the oil, such as pepper, truffle, and vegetable.  
\end{table} 
Table 3: Cadmium (Cd) content in edible vegetable oils, expressed in mg/kg. oils from China and Pakistan, with values of 1.96 and between 1.301 and 6.765 mg/kg, respectively [42; 80].