Natural cadmium loading and balance in a non-polluted rice paddy field in Japan.
We determined the natural Cd balance in a cultivated rice paddy field in Japan. The main sources of Cd in the non-polluted paddy field were phosphorus fertilizer and precipitation (annual input of Cd, 2,000 mg ha(-1) and 1,020 mg ha(-1), respectively). These sources account for 95% of the total input of Cd (3,192 mg ha(-1)). The actual increase of Cd in the soil was 0.0016 mg kg(-1), we thus consider Cd in soil increases only slightly as a result of rice culture. This study indicates that it is difficult to reduce Cd loading by irrigation water treatment in a non-polluted paddy field. This further indicates that once a field is polluted by Cd it is difficult to decrease the accumulated Cd by the ordinary cultivation of rice plants.
Yada
Saeko
S
National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Japan. helios02@niaes.affrc.go.jp
Arao
Tomohito
T
Kawasaki
Akira
A
Saito
Takayuki
T
Nagai
Hideyuki
H
Mano
Masayoshi
M
Hamada
Yohei
Y
D000042:Absorption; D000383:Agriculture; D002104:Cadmium / Q000032:analysis*; D004784:Environmental Monitoring; D004787:Environmental Pollution; D005843:Geography; D007564:Japan; D012275:Oryza; D014867:Water
D002104:Cadmium; D014867:Water