Lead and Cadmium Concentration in Agricultural Crops (Lettuce, Cabbage, Beetroot, and Onion) of Isfahan Province, Iran

The contamination of agricultural crops with heavy metals due to soil and atmospheric contamination is a potential threat for their quality and their safety. Heavy metals such as Cd and Pb have been reported for their carcinogenic effects. The aim of this study was to investigate the lead and cadmium concentration in some of crops grown in Isfahan province, Iran. During two seasons (spring and summer), 80 samples of four different crops (20 samples from each crop) were randomly harvested from some of the agricultural lands of Isfahan province. After sample preparation, lead and cadmium contents were determined by atomic absorption spectrometry. The average concentration of Pb and Cd were different in different crops. A significant difference (p<0.05) was observed between mean concentration of lead in beetroot with onion and also cabbage whereas no significant difference was observed for lead between beetroot and lettuce (p>0.05). Means comparison showed a significant difference for cadmium between beetroot and cabbage and also beetroot and onion (p<0.001). Results showed that the concentration of Pb and Cd in most of the samples was higher than the standard limits reported by Iran (maximum tolerance of heavy metal in lettuce, cabbage, rootbeet and onion is 0.2, 0.3, 0.1, and 0.1 for lead and 0.1, 0.05, 0.05 and 0.05 UNIT for cadmium respectively) and FAO-WHO. The findings of this study indicated that although most of the sampling plants were contaminated with lead and cadmium, the estimated daily intake of each metal (EDI) showed that except lead in lettuce, other crops have EDI below the provisional tolerable daily intake (PTDI) recommended by the Institute of Standards and Industrial Research of Iran. In order to better management, preventing pollution and also finding the origin of elements, analyzing heavy metals content in soil, water, and dust of this region is recommended.