兵庫県における 農用地土壌汚染対策について

Countermeasures for
Agricultural Land Soil Pollution
in Hyogo Prefecture
June 25, 2014
Hyogo Prefectural Government
Agricultural & Environmental Affairs Department
Agriculture, Forestry & Fisheries Bureau
Agricultural Improvement Division
Environmental Development type Agriculture
Promotion Group
Overview of “Agricultural Land Soil Pollution Prevention Law”
Objects
The Law aims at the prevention of the production of agricultural
crops and livestock which are feared to be harmful to human health or
the prevention of the obstacle of the growth of agricultural crops and
others to be helpful for the protection of national health or the
preservation of a good living environment, by establishment of
necessary policies which are useful for the prevention of agricultural
land soil pollution caused by specific harmful substances or the
elimination and which are useful for the rationalization of utilization of
polluted agricultural land
Mechanism
•
•
•
•
Designate the areas where soil contamination is found as agricultural
land soil pollution policy areas (Hereinafter referred to as ‘Policy
Areas’)based on the continuous monitoring by prefectures, make
countermeasures and implement remedial measures like soil dressing
etc.
“Protection of human health” (Cadmium) & “preventing growth inhibition
of agricultural crops” (Copper & Arsenic) could be the reasons for
designation
Set 0.4ppm for cadmium to ensure consistency with the specification
standard of Food Sanitation Act (for rice)
When the countermeasures are completed, confirm the effect by
investigation of Policy Areas and cancel the designation
1
Mechanisms of “Agricultural Land Soil Pollution Prevention Law”
Sources
of
pollution
Continuous
monitoring
Confirm
contamination
Fact-finding
investigation of soil
pollution (prefecture)
Designate
agricultural land
soil pollution
policy areas
(prefecture)
Designated hazardous
substances
Local
government
Pollution Control
Public Works Cost
Allocation Law
Design
agricultural land
soil pollution
policy project
(prefecture)
Central
government
Cost
Implement
improvement
work
Enforced by prefecture
or municipalities
Designation standard for
agricultural land soil
pollution
Law Concerning Special
Government Financial
Measures for Pollution
Control Projects
Cancel
designation
(prefecture)
Remarks
Cadmium and its
compounds
Concentration in brown rice
exceeds 0.4mg/kg(0.4ppm)
Protection of human health
Copper and its
compounds
Concentration in soil
125mg/kg(125ppm) or more
Preventing growth inhibition of
agricultural crops
Arsenic and its
compounds
Concentration in soil
15mg/kg(15ppm) or more
Preventing growth inhibition of agricultural crops
The governor can decide within the range of 1020ppm depending on the natural condition
2
History of Agricultural Land Soil Pollution
Prevention in Hyogo Prefecture
•
Agricultural land soil is polluted by effluent of suspended or abandoned
mines, by industrial waste water or by falling dust (Mine effluent and factory
waste water are the main sources in Hyogo prefecture)
•
There are several hundreds of suspended or abandoned mines, mainly in
Chugoku mountain region in Hyogo prefecture
•
In 1970, the Ministry of Agriculture, Forestry and Fisheries conducted a
nationwide investigation of suspended or abandoned mines etc. and
surrounding areas. As a part of this nationwide investigation, water pollution
special investigation or special investigation for harmful substances were
carried out and revealed the contamination condition of hazardous
substances like cadmium
•
For five years from 1971 to 1976, the Ministry further implemented
Agricultural Land Soil Pollution General Investigation (General investigation
for heavy metals) and 104 points were monitored in Hyogo prefecture
•
Hyogo prefecture has been actively engaged in solving the cadmium
pollution of agricultural land soil from the early stage
3
Current Soil Pollution Status of
Hyogo Prefecture
• Thanks to the countermeasures taken from 1972, all the
listed agricultural land soil pollution policy areas of
Hyogo prefecture were canceled as of May 2, 2001,
when K town was de-registered for completion of
remediation of Cadmium
• 5 Areas were designated and executed remediation
measures like soil dressing etc. Some areas conducted
countermeasures without being designated
• As for the surrounding area of Ikuno Mine, conducted
brown rice and soil survey as part of Cadmium etc.
concentration investigation (observation type
investigation) and gave guidance to thoroughly execute
farming method to inhibit Cadmium absorption like
flooding management etc.
4
The Concept of Risk Management
Cd concentration
vary in different
products
Products suspected to lower concentration
Cd absorption differs depending on
agricultural products or varieties
Products suspected to higher concentration
Transfer of products
In case transfer of product is difficult
Cd concentration of edible
part vary in different varieties
Varieties suspected to lower concentration
Varieties suspected to higher concentration
Transfer of varieties
In case transfer of varieties is difficult
Products & Varieties with less risk
of absorption
×
Make soil to proper condition
(Apply alkaline materials &
fertilizer)
Target pH 6.5-7.0
The reduction ratio of Cd concentration in
proportion to pH elevation in soil
Susceptible to decline
Suppress absorption by
applying alkaline
materials & fertilizer
Not susceptible to decline
Cleaning method by plants &
dressing soil etc.
5
Current measures taken by
Hyogo Prefecture
1 Observe progress by investigating Cadmium
concentration etc.
2 Give guidance of Farming method to suppress
absorption of Cadmium
3 Conduct “Cadmium Test” based on Food
Sanitation Act
4 Promote Agricultural Land Soil Cleaning Method
by Plants Project
6
1 Investigation of Cadmium Concentration etc.
•
•
•
•
The pollution expanded in a wide range for the surrounding area of Ikuno
Mine, including the neighboring Akenobe Mine. Thus, even after the
completion of the remediation, observation survey of Cd concentration of soil
and brown rice (standing crop; the condition before harvest in the field ) is
continuously conducted to monitor the contamination condition. 12 sampling
points every year
Following the Implementation Guideline of Cadmium Concentration etc.
Investigation, got previous permission of the related municipalities, sought
comments of the relevant municipality and drafted the investigation plan
The designed investigation plan is notified to the Director of Hyogo
Prefectural Technology Center for Agriculture, Forestry and Fisheries and
ask for the cooperation to the investigation
Based on the Implementation Guideline of Cadmium Concentration etc.
Investigation, the result is made public (published in official written reports of
the prefecture)
項 目
Items
Sampling time
採 取 時 期
分 析 項 目
Analytic Items
備 考
remarks
玄 米
Brown
rice
Before harvest (within 1 week)
収穫前(1週間以内)
Cd Cd
外部委託
soil
土 壌
When taking samples of brown rice
玄米採取時
Cd (in soluble form)
Cd(可溶態)
Out sourcing
外部委託
Out
sourcing
7
2 Guidance of Farming method to suppress
absorption of Cadmium
• As for regions where no measures, like dressing soil
construction work to permanently stabilize its safety is taken,
give guidance to invest soil improvement materials (Calcium
Carbonate or Bentonite, which is a viscous mineral) or
farming technology to suppress cadmium absorption by
thorough flooding management of paddy rice etc.
• Give guidance and advice to the cultivation calendar making
by Agricultural Cooperatives
• The prefectural government, municipalities and Agricultural
Cooperatives integrally guide cultivation method, make tour of
paddy fields and alert the attention through the Radio
Broadcasting system
• From Feb. 28, 2011, Cadmium specification standard of Food
Sanitation Act has been strengthened. Thoroughly notify to
farmers the farming technology to suppress cadmium
absorption via related institutions and organization and
promote voluntary inspection before shipping at production
area with Agricultural Cooperatives taking the lead
8
Alkaline materials (Lime materials) 【Paddy rice】
Cd concentration in soil
A:1.0 B:2.6
玄米カドミウム濃度(ppm)
2.5
2.0
土壌 B
1.5
y=-0.521x+4.35
r = -0.866
1.0
土壌 A
0.5
y=-0.248x+1.93
r = -0.981
0.0
4
4.5
5
5.5
6
土壌pH
6.5
7
7.5
8
If elevate the pH level of soil, Cd concentration of brown rice
is in decline→Alkaline materials are effective
If concentration is around 1ppm, pH7 level enables to
suppress Cd concentration of brown rice without any flooding
management
9
Flooding Management
Drying up
1.5
玄
米
カ
ド
1.0
ミ
ウ
ム
濃
度 0.5
0.4
p
p
m
Flooding Management against Cd (3 weeks before &
after ear emergence
■intermittent irrigation
間断かん水
Cd concentration in brown rice may
exceed standard
◆Flooding Management
Cd concentration in soil may be high but
that in brown rice is below standard
湛水管理
0.0
6.0
6.1
土壌pH
6.2
*Result with Cd concentration in soil
2.6ppm
6.3
Flooding management
is very effective in
paddy rice
10
3 “Cadmium Test” based on Food Sanitation Act
• In compliance with the “Hyogo Prefectural Plans
for the Monitoring of and Guidance on Food
Sanitation” based on Food Sanitation Act,
Health & Welfare Office conducts removal test
centering for areas having a history of Cadmium
pollution to secure safety of circulating rice
• In case 0.4ppm or more is detected in the test, it
is necessary to take measures to determine the
cause etc.
→ Call related institutions and establish
countermeasures meeting
11
4 Promote Agricultural Land Soil Cleaning Method by
Plant Project
Implement in the area where cadmium is detected more than 0.4ppm or more in brown rice
In contrast with the soil dressing construction work, the above method can mitigate
the Cadmium concentration in soil in lower cost and expect the decline of risk of
agricultural products with exceeding standard produced not temporarily but further in
the future as well
1) Experimental proof of Soil cleaning method by plants
As one of the countermeasures against Cadmium soil pollution of agricultural land,
a soil cleaning method using Cadmium high absorption plants to lower Cadmium
concentration in soil (phytoremediation) is put toward practical use. Experiment to
prove the effect of plant cleaning method is implemented at local paddy fields
After one year application of this cleaning method, Cadmium concentration (in
soluble form) of plowed soil decreased by 10-26% and exceeded the normally
expected value of 10%
2) Experimental proof of less Cadmium absorption type rice
Compared with the popular variety “Koshihikari”, there is a variety expected to
lower the risk because of its character to absorb less Cadmium.
After taking the same management of experimental paddy field for the first year, the
cadmium concentration of the new variety was lower than that of “Koshihikari”.
The new variety is expected to be the main crop in this area in the future
12
Cleaning Method by Plants (Phytoremediation)
Soil condition
suitable for more
absorption
Low
Moisture
Low pH
Let the special plants
absorb and take them out
Cd Cd Cd Cd
Cd Cd Cd Cd
Cd Cd Cd Cd
長香穀
(高吸収イネ)
Cd concentration in soil
decreased
Cd
Cd
Cd
Cd
Problems: Takes a lot of years & Treatment of the harvested crops
13
Low Cd Absorption Variety (paddy rice)
イオンビーム育種(農環研)
Soil Cd:0.35~1.4ppm
Hardly absorb Cadmium despite high Cd concentration in
soil and water saving conditions
The yield & quality are almost equivalent to those of the
popular “Koshihikari” variety
14
In conclusion
• As for the countermeasures for agricultural land soil pollution, the related institutions like municipalities,
Agricultural Cooperatives and producers should cooperate in both hardware side (e.g. soil dressing
construction work) and software side (e.g. Making cultivation calendar, making tour of paddy fields or
guidance of cultivation method)
•Because soil dressing work costs a lot, it is necessary to make a comprehensive study taking into
consideration cleaning method by plants or cultivation of crop varieties with less absorption of Cadmium
as options
Agricultural
Improvement Division
Agriculture & Horticulture
Division
Training session &
public relations activities
Recommend varieties
Liaison Committee
Extension Center
Agricultural Technology
Institute
Farming site
Producer
Guidance to cultivation
management
JA ZEN-NOH
Guidance &
Coordination
Establish
countermeasures
technology
Municipalities
Crop design
15