Sixty-one soil samples and corresponding leafy vegetable samples were collected from Dongguan which is a Township-Enterprise-Prosperity-Area of Guangdong Province
the total content and extractable concentration of 5 heavy metal elements (Cu
Zn
Cr
Ni and Pb) were measured. Results show that the leafy vegetables have obvious problems of both the excess of toxic metal (Pb
Ni) and the shortage of useful metal (Zn
Cu). The metal concentrations in leafy vegetable had no significant correlations with either the total or the extractable heavy metal concentrations in soil. While the heavy metal concentration in leafy vegetable evidently related to the accumulation factors calculated from extractable heavy metal concentration. It might indicate that using the extractable heavy metal to evaluate the effect of heavy metal to the crop in soil was not enough to reflect the adverse effects to ecological system. The same type of vegetables have different absorbability to different heavy metals
different vegetables have different absorbability to the same heavy metal. Generally,the leaf vegetables have strong selective absorbability to heavy metals. Cr was the easiest element to be selectively absorbed,Zn
Cu
Ni was the second
Pb was the weakest absorbed. But the extractable content and the ratios of extractable content to total content of Cr
Zn
Cu in soils are low,the content of Cr
Zn
Cu in vegetables are not exceeded the limits of standard of food sanitation. The source of excessive lead in vegetable is complicated and mostly originates from air polluted with lead.