National Institute for Agro-Environmental Sciences, Japan

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Temporal Trend of POPs Residue in Japanese
Agricultural Soils
Nobuyasu SEIKE

• National Institute for Agro-Environmental
  Sciences, Japan

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Preserved Soils
Agricultural soils (paddy and upland)
periodically collected from all over Japan since
1960s are preserved in the National Institute for
Agro-Environmental Sciences (NIAES).
Sampling Sites
(15 sites)
Dioxins and Dioxin-like PCBs
7 sites
Air-dried and sieved (lt2 mm) soils were
preserved in polyethylene bottles at room
temperature.
Organochlorine Pesticides
15 sites
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Topics
? Temporal changes of dioxins and dioxin-like
PCBs concentrations associated with their sources
in paddy soils
? Temporal changes of organochlrine pesticides
concentrations in paddy soils
? In order to provide the factors for the decline
of POPs in soils, half-lives for the
disappearance of POPs in paddy soils were
calculated.
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Dioxins (PCDD/Fs)
PCDDs
PCDFs
(x y 1 8)
(x y 1 8)
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Temporal Change of PCDD/Fs Conc. in Japanese
Paddy Soils
Max.
Ministry of Environment and Ministry of
Agriculture, Forestry, and Fisheries (2001)
Mean
Min.
pg-TEQ g-1-dry
Sampling Year
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Emission of PCDD/Fs, and OCDD 1,3,6,8-TeCDD
Concentration
OCDD Conc.
1368/1379-TeCDD Conc.
PCP
CNP
Year
Rapid increasing of PCDD/Fs concentrations are
due to use of PCP and CNP
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PCA Plot
Site 2
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Quantitative Source Identification by CMB
developed by Kashiwagi (2002) J. Appl. Statist.
1960 (before PCP use) originated from
combustion processes
early-1960s mid-1960s PCP
end-1960s PCP and CNP (exceed 95)
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Mass Balance of PCDD/Fs in Japanese Paddy Fields
(1958-2000)
Half-lives 17.6 yr
Runoff 2 / yr
Masunaga et al. EST (2001)
Cumulative Input
Disappearance from Paddy Field
Ministry of Environment and Ministry of
Agriculture, Forestry, and Fisheries
Nationwide Survey
(1999-2002)
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Dioxin-Like PCBs
non-ortho PCBs
mono-ortho PCBs
12 Congeners
Known major source
- Commercial PCBs (Kanechlors)
Total PCBs use in Japan
50 ﾗ106 kg
banned at 1974
- Combustion Processes
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Temporal Trend of Dioxin-like PCBs
Concentrations in Paddy Soils
Max.
Mean
pg-TEQ g-1-dry
Min.
Year
Dioxin-like PCBs concentrations were considerably
lower than PCDD/Fs.
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The Ratio of 126 to SPentaCBs
The ratio of 126 to SPentaCBs have been
increased since 1970s
Dioxin-like PCBs originated from combustion
processes have been increasing gradually
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Organochlorine Pesticides (OCPs)
Compounds
Usage in Japan (A.I base)
Banned Year
Aldrin 2.5ﾗ106 kg
Dieldrin 0.7ﾗ106 kg
Endrin 1.5ﾗ106 kg
Chlordanes 0.2ﾗ106 kg 17 ﾗ106 kg for domestic pest control
DDTs 23 ﾗ106 kg
HCHs 280 ﾗ106 kg
Heptachlors 1.5ﾗ106 kg
HCB Not Registered
Mirex Not Registered
1975
1975
1975
1968
1986
1971
1971
1975
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Temporal Change of OCPs Conc. in Japanese Paddy
Soils
Chlordanes
HCB
HPCLs
Mirex
Temporal changes in OCPs concentrations in paddy
soils reflected the use of pesticides.
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Temporal Change of OCs Conc. in Human Breast
Milk from Osaka, Japan
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Half-lives in Paddy Soils
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Kow vs Half-lives
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Correlations between Half-lives and
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Concluding Remarks
? In Japan, use of OCPs was already banned in the
early 1970s.
? PCP and CNP was also banned in the 1990s.
? The content of PCDD/Fs is checked at the
agricultural chemicals registration
? The emission gas controls on waste incinerators
and improvements of incineration facilities have
been imposed since end of 1990s by the Japanese
government
It is, therefore, expected that further POPs
contamination on agricultural soil will not
occur, and POPs concentrations in agricultural
soil as well as air, water and biota, will
decrease gradually.
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Acknowledgments
I thank Dr Otani, T. and Dr Eun, H. National
Institute for Agro-Environmental Sciences, for
useful discussions.
This work was supported in part by a Grant-in-aid
(Hazardous Chemicals and Environmental Research)
from the Ministry of Agriculture, Forestry and
Fisheries and the Ministry of Environment, Japan,
respectively.