13. Da Nang Airbase Case Study - Introduction and Banckground_TB

Transcription

Regional Capacity Building Program for
Health Risk Management of
Persistent Organic Pollutants (POPs) in
South East Asia Program
© Hatfield Consultants. All Rights Reserved.
7/14/2009
SLIDE 1
Da Nang Airbase Case Study –
Introduction and Background
by Thomas G. Boivin
Final Regional POPs Workshop
Da Nang, Viet Nam, July 22 -24, 2009
7/14/2009
SLIDE 2
1
Presentation Outline
Introduction
Objectives of 2006 Da Nang
Study
Methods used for Da Nang
2006 Study
Results
Conclusions and Proposed
Mitigation Measures
SLIDE 3
Agent Orange Facts:
Area sprayed: >21,000 km2
(2 million ha).
55% of all mangrove forests
destroyed.
>80 million litres of
herbicides sprayed.
>600 kg of TCDD released to
environment.
Key AO Hotspots – Former US
bases in Bien Hoa, Da Nang,
Phu Cat, Tan Son Nhut,
Pleiku, Nha Trang, Can Tho.
Other Hotspots may exist.
Present day issue – not an
historical problem
Da Nang Facts (2005):
Population – 750,000;
3rd largest city in Viet
Nam;
2nd largest Ranch Hand
Site (after Bien Hoa);
>100,000 45-Gallon
(208 liter) barrels of
herbicide used on Da
Nang Airbase;
Primarily loaded on C123 Aircraft – also
backpack spraying;
Significant spillage;
Empty barrels sold to
residents of Da Nang.
SLIDE 4
2
Objectives of Da Nang Dioxin
Assessment and Mitigation Project
1.
Assess the levels of dioxins,
furans and other contaminants in
the environment and human
population in the vicinity of the
Da Nang Airbase; and,
2.
Assist with protection of human
health and development of
mitigation measures for Da Nang.
SLIDE 5
SLIDE 6
3
Methods
Based on previous Hatfield/10-80/Office
33 sampling programs;
Fieldwork conducted December 2006
and January 2009;
Soils, sediments, fish, vegetation and
human blood/milk sampled;
Airbase and Da Nang City sampled;
Focus on Storage/Mixing/Loading Areas,
and aquatic ecosystems;
Questionnaires surveys;
AXYS Laboratories (Canada) using highresolution GCMS.
SLIDE 7
SLIDE 8
4
Results of Detailed Investigation in Da
Nang (2006)
Former Agent Orange
Storage and
Mixing/Loading Areas
SLIDE 9
Results
SLIDE 10
5
SLIDE 11
CONTAMINANTS EXAMINED AND
NUMBER OF SAMPLES ANALYZED IN 2006
Dioxins/furans (all congeners) N=75 soil/sed;
55 blood; 12 fish; 2 vegetation;
2 breast milk; 2 water; Total = 148;
Organochlorine pesticides N=5;
PCBs N=18 blood; 8 soils;
PAHs N=5;
Chlorinated phenols N=4;
Volatiles and Hydrocarbons N=2;
Heavy Metals N=7;
TOC, PSA, pH N=6;
Radio isotopes, Pb, Ra, Cs N=7;
GRAND TOTAL=210 Samples Analyzed
SLIDE 12
6
Standards Based Approach
Dioxin/furan and other contaminants were
compared with international guidelines;
Generally, TEQs should not exceed:
Soils >1,000 ppt (ATSDR 1997);
Sediments >100 ppt (Various sources);
Fish tissues >20 ppt (Health Canada);
Blood between 3-7 ppt (Typical values
for industrialized countries).
Values should be lower for Viet Nam,
given close contact with environment.
SLIDE 13
Soils – Former Mixing/Loading Area and Storage Area
Hot Spots (TCDD & TEQ; ppt)
Mixing/Loading Area
SLIDE 14
Storage Area
Perimeter Drainage
7
Danang City Soils/Sediments
(TCDD & TEQ; ppt)
SLIDE 15
Sen Lake, Lake B, Lake C Sediments
(TCDD & TEQ; ppt)
>1983
SLIDE 16
8
Delineation of Da Nang Hot Spot
SLIDE 17
Fish & Vegetation in Da Nang (TCDD & TEQ; ppt
wet weight)
SLIDE 18
9
Human Blood - Da Nang (TCDD & TEQ; ppt lipid
basis)
SLIDE 19
Results – Soil/Sediment
1.
2.
3.
4.
High concentrations of 2,3,7,8-TCDD contaminate soils and
sediments at the north end of Da Nang Airbase (up to
365,000 ppt).
The source of this contamination was war-time use of Agent
Orange by the US and ARVN forces (>90% TEQ was from
2,3,7,8-TCDD).
Contamination has continued for decades.
Investigations confirm Da Nang Airbase as a significant ‘Hot
Spot’.
SLIDE 20
10
Results – Food Items
The food-chain is being
contaminated primarily through
sediment/soil transport to aquatic
organisms (fish, other animals,
lotus);
2. Contaminated food is being eaten
by residents in Da Nang; some is
being sold in local markets;
3. Maximum 3,000 ppt (wet weight)
in Tilapia fat tissue.
1.
SLIDE 21
Results – Human Populations
1. Blood dioxin levels were the highest reported for Viet
Nam to date.
2. The highest level was 1,220 ppt TEQ (94% or 1,150
ppt TCDD); two other individuals who were fishing
and farming inside the Da Nang Airbase perimeter
had >500 ppt TEQ.
3. These levels are an unacceptable health risks to
exposed populations.
4. Total highly exposed group is probably <50 people,
but needs confirmation.
SLIDE 22
11
Conclusions and Recommended
Mitigation Measures (1)
1.
2.
Fishing/lotus harvesting on all waterbodies on Da Nang Airbase
(Sen Lake, Lake B, and Lake C) should be terminated. *
A secure, permanent fence around the perimeter of the Airbase,
particularly at the northern border, is required to prevent access.
*
* Recommendations already implemented or in progress
SLIDE 23
Conclusions and Recommended Mitigation
Measures (2)
3. Fish ponds on the West Airbase should be
decommissioned, and no further excavation
of fishponds should be permitted on the
Da Nang Airbase. *
4. Cultivation of vegetables should be
prohibited on the Airbase. *
5. Fish consumption in Xuan Lake and March 29
Lake should also be prohibited, as a
precautionary measure. *
* Recommendations already implemented or in progress
SLIDE 24
12
Conclusions and Recommended Mitigation Measures
(3)
6. Follow-up consultations with
individuals who were tested for
blood/milk dioxin levels (by qualified
professionals). *
7. Simple education materials for Da
Nang residents to help reduce
potential exposure through
contaminated food. *
* Recommendations already implemented or in
progress
SLIDE 25
Conclusions and Recommended Mitigation Measures
(4)
8. Engineered solutions at the former Mixing and Loading Area and Storage
areas to be refined and implemented as soon as possible. *
9. Regular dioxin monitoring (5-7 year minimum) in the vicinity of Da Nang
to verify to effectiveness of mitigation measures.
* Recommendations already completed or in progress (Interim containment: fences,
capping at mixing and loading area, and sediment treatment. Final containment to
be decided: capping and landfills?)
SLIDE 26
13
Thank You
For further information contact:
Thomas Bovin
HATFIELD CONSULTANTS
201 – 1571 Bellevue Ave.
West Vancouver, BC, CANADA
V7V 1A6
Phone 604.926.3261
tboivin@hatfieldgroup.com
www.hatfieldgroup.com
7/14/2009
SLIDE 27
14

13. Da Nang Airbase Case Study - Introduction and Banckground_TB

Transcription

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