Levels of heavy metals (Pb, Cd, Cr and Ni) in two types of lettuce marketed in city of Hamedan

Considering the importance of food security and adverse effects of potentially toxic elements (PTEs) on human health, the present study was conducted to assess the contents of Pb, Cd, Cr and Ni in two types of lettuce (Romaine lettuce and Iceberg lettuce) marketed in city of Hamedan in 2013.

In this descriptive study, a total of 15 samples of each type of lettuce were purchased. After acid digestion of samples in the laboratory, the Pb, Cd, Cr and Ni contents were determined using anodic stripping voltammetry. All statistical analyses were performed using the SPSS statistical package.

The results showed that the average contents of Pb, Cd, Cr, and Ni in leaves and stems of Romaine lettuce were 19.3 and 40.6; 103 and 233; 8.00 and 22.8; and 30.2 and 171 mg/kg, respectively, while, the average contents of Pb, Cd, Cr, and Ni (mg/kg) in leaves and stems of Iceberg lettuce were found to be 9.07 and 20.8; 35.4 and 118; 12.9 and 37.8; 215 and 279, respectively. Also, based on the results obtained, except for Ni in Romaine lettuce, the mean contents of all the analyzed elements were significantly higher than the maximum permissible concentration (MPC) established by FAO/WHO.

In conclusion, due to studied lettuces were not suitable for consume by human, therefore, regular monitoring of foodstuffs should be noticed in order to maintenance the consumer's health.