Determination of heavy metal in four varieties of soy bean cultivated in Iran

BACKGROUND AND OBJECTIVE: Heavy metal contamination due to increase use of chemical fertilizers and human activity make it as a global concern. Soybean as a metals bioaccumulator, could cause some problems. Its beneficial properties such as high content of protein and fat make it to be substituted in dietary program. Therefore, it may highlight the importance of heavy metal carry over by soybean and its products. In current study, heavy metal content (Zn, Ni, Pb, Cd and As) of four variety of soybean were investigated. METHODS: Four varieties of soybean which cultivated in Iran, were collected and wet digested. They were put on the hotplate to complete the digestion. Then solution was filtered and fills to exact volume of 25.0ml with distilled water. Metal concentration of samples was analyzed by ICP-OES. FINDINGS: According to our results, as content of all samples were ranged from 0.008 to 0.021mg/kg DW. The highest cadmium content 0.16mg/kg, which was lower than Codex standard (0.2mg/kg). Ni content was reported from 10.22 to 11.21 mg/kg. The maximum Pb level in samples was 0.081 mg/kg, which was lower than allowable limit. Zn content was ranged from 64.10 to 65.3mg/kg. The standard allowable content for Zn is considered 100mg/kg. CONCLUSION: Our study provides that heavy metal content of all samples were below the maximum limits, therefore there is not any concern in soybean contamination in Iran. Because of the industrialization of cities, regular monitoring of soybean is necessar