contaminated with Cd (6.4 mg/kg) an

contaminated with Cd (6.4 mg/kg) and weakly contaminated with
Cu (256.4 mg/kg) and Zn (209.9 mg/kg). Furthermore, a heavy metal
investigation in one village in Taizhou conducted by Fu et al., 2008
indicated that the paddy soil was primarily contaminated by Cd
(1.19 mg/kg), followed by Cu (98.8 mg/kg). Consistent with the
above two studies, the paddy soils in Wenling and Taizhou were also
contaminated with Cd, Cu, Ni, Pb and Zn to different degrees, and
some areas posed potential high-risk levels of Cu, Ni and Zn, and
especially Cd (Zhao et al., 2010, 2011). In addition, 3 types of sampling
sites in Wenling were analyzed and compared (Tang et al.,
2010b). Hg, Cu, Cd, Pb, and Zn were the most abundant metals found
in the environmental samples, and Hg was the most serious metal
pollutant in the Wenling area, with the Hg content exceeding the
Grade II value (0.3 mg/kg) by 1.3–739 times. It was also found that
simple household e-waste recycling workshops could cause even
more serious heavy metal pollution, compared with large-scale
e-waste recycling plants and large-scale gold recovery plants.
Three studies investigated heavy metal levels in the soil in
Longtang, Qingyuan. (Luo et al., 2008a, c) found that the soil of
e-waste open burning sites and e-waste disassembling workshops
have been obviously polluted by heavy metals, at much higher
than the maximum allowable concentrations of the national soil
standards, especially for the Pb, Cu and Cd levels. Luo et al., 2011
reported that the soils of former incineration sites had the highest
concentrations of Cd, Cu, Pb, and Zn, with mean values of 17.1,
11,140, 4500, and 3690 mg/kg, respectively. The soils of nearby
paddy fields and vegetable gardens also had relatively high concentrations
of Cd and Cu. In contrast to the above studies, Li
et al., 2011a found that heavy metals remained near the pollution
source instead of diffusing into the surrounding areas, a result
likely due to low vapor pressure.