Survey of aflatoxin B1 and heavy metal contamination in peanut and peanut soil in China during 2017–2018

Abstract

Peanut, as a nutritious, healthy and delicious food, is susceptible to contamination by aflatoxin B1 (AFB1) and heavy metals, which has an adverse impact on the healthy development of peanut industry in China. This research was to evaluate the contamination of AFB1 and heavy metals (cadmium, chromium, lead, tin, copper and zinc) in peanut, to analyze the difference of AFB1 and heavy metal contamination in peanut in the four main peanut producing regions (Northeast area, Yellow River basin, Yangtze River basin and Southeast coast), and to analyze and discuss the difference of heavy metal content in peanut kernel, peanut shell and peanut soil. The results showed that the mean concentration of AFB1 in peanut was 1.08 μg/kg, and the detection rate of AFB1 was 33.80%. There was no significant difference in AFB1 contamination of peanut between 2017 and 2018. The most serious AFB1 contamination region was the Yangtze River basin, followed by the Southeast coast, the Yellow River basin and the Northeast area. The average levels of cadmium (Cd), chromium (Cr), lead (Pb), tin (Sn), copper (Cu) and zinc (Zn) in peanut kernel were 0.18, 0.44, 0.03, 0.01, 9.24 and 31.42 mg/kg, respectively. There was a significant difference in the mean content of heavy metals (Cr, Sn, Cu and Zn) in peanut kernels between 2017 and 2018. The mean content of Cd in peanut kernel was the highest in Northeast area, and there was no significant difference in the mean content of Pb in the four main peanut producing regions. The average concentration of other heavy metals (Cr, Sn, Cu and Zn) in peanut kernel in south of China (Yangtze River basin and Southeast coast) was higher than that in north of China (Northeast area and Yellow River basin). Due to the different bio-accumulation ability of peanut kernel and peanut shell to different heavy metal, the average levels of heavy metals in peanut kernel and peanut shell were different. The ability of peanut kernel to bio-accumulate Cd, Cu and Zn was stronger than that of peanut shell, and the ability of bio-accumulate of Cr, Pb and Sn was weaker than peanut shell. There was a significant positive correlation between heavy metal pollution of peanut and heavy metal content in soil. In conclusion, the situation of AFB1 and heavy metal contamination in peanut in China was not optimistic, and the pollution of peanut in south of China was more serious than that in north of China. Therefore, the control and prevention of AFB1 and heavy metal in peanut should be strengthened.