Abstract: The contents of lead(Pb) in the soil,bark,leaf,walnut peel,shell,and kernel in Panxi region's walnut were determined by using the atomic absorption spectrometry to study the accumulation characteristics and consumption risk. The results showed that the contents of Pb in the soil were significantly higher than those in the organs of the walnut tree,and one of the soil samples was exceed the national standard;the contents of Pb in the leaves were significantly higher than those in the walnut peel,shell,and kernel;with the increase of Pb content in the soil,the Pb contents in bark,leaf,walnut peel,shell,and kernel didn't show an obvious enrichment regularity,and the accumulation ability of Pb in the walnut kernel was weaker compared with the other main organs. The results of the Nemerow Index Method showed that the pollution index of Pb in the walnut kernel was less than 1,which indicated that the kernel samples of the experimental point in Panxi production base were out of Pb pollution. Referring to China's current standards,the target risk factor of Pb in the walnut was figured out by extending the tree nuts consumption of Chinese residents to the recommended value and much lower than 1.0, which meant the content of heavy metal Pb in the edible parts of walnut was temporarily risk-free for Chinese consumers' health.

Key words: walnut, lead, accumulation characteristics, risk assessment