Agriculture Reference
In-Depth Information
by As (total As < 25 mg kg
-1
) (Simmons et al., 2008). In the study of Zavala & Duxbury
(2007), the rice samples collected from many countries may not be representative of major
rice consumption in those countries, it is necessary to conduct a comprehensive survey for
As concentrations in different rice cultivars produced in Taiwan to estimate the normal
levels of As in rice and compared with the data from Guandu Plain.
0.4
0.3
0.2
0.1
0.0
0
100
200
300
400
500
600
Soil total As concentration (mg kg
-1
)
Fig. 6. The relationship between As concentration in soil and in brown rice collected
together from 13 paddy fields in Guandu-Plain, north Taiwan.
Country/Institute
Regulation item
Statutory limit
Reference
Australia
cereals
1 mg kg
-1
FW
Brus et al., 2009
Canada
food crops
1 mg kg
-1
FW
Zandstra & Kryger, 2007
China
rice
0.15 mg kg
-1
DW*
URL, 2005
New Zealand
cereals
1 mg kg
-1
FW
Brus et al., 2009
Switzerland
food crops
4 mg kg
-1
DW
Gulz et al., 2005
United Kingdom
food in sale
1 mg kg
-1
FW
Warren et al., 2003
FW: fresh weight; DW: dry weight; *: limit for inorganic As
Table 9. The statutory limits of arsenic concentration in cereals or food corps announced by
WHO or different countries.
Many studies found that the arsenic concentration in rice grain harvested from As-
contaminated soil could reach above 0.7 mg kg
-1
. However, rice produced in Guandu Plain
is not apparently affected by As-contaminated soil. The availability of As in soil may be very
low. To investigate the distribution of As forms associated with soil solid phases, an As-
specific sequential extraction procedure proposed by Wenzel et al. (2001) was conducted for
the collected 13 soil samples.
