
February 25, 2008
Mr.
Luis A. Ubiñas
President
Ford
Foundation
320 East 43rd Street
New York, N.Y. 10017
RE: Assessment of Dioxin Contamination in the
Environment and Human Population in the Vicinity of Da Nang Airbase, Viet Nam
Dear
Mr. Ubiñas:
We thank you for providing us with a
copy of the report entitled “Assessment of Dioxin Contamination in the
Environment and Human Population in the Vicinity of Da Nang Airbase, Viet Nam,”
which was prepared by Hatfield Consultant of West Vancouver, Canada (Hatfield)
and Office of the National Committee 33, MONRE in Ha Noi, Viet Nam (Committee
33) and dated April 2007 (Da Nang Report).
The copy was forwarded to us by Hatfield on January 23, 2008.
The Da Nang Report presents results of
the Da Nang Dioxin Assessment and Mitigation Project (DDAMP) funded by Ford
Foundation. This is just one of the greatly
appreciated efforts Ford Foundation has made in “helping the people,
institutions, and government of Vietnam build a strong, healthy, and vibrant future.” We wish the Ford Foundation goals -
strengthen democratic values, reduce poverty and injustice, promote
international cooperation, and advance human achievement – will succeed in
Vietnam.
The Da Nang Report provides, for the
first time, significant amounts of data and information regarding one of the
presumed dioxin hot spots in Vietnam; however, they do not appear to be
adequate to conclude that Agent Orange used during the Vietnam War is the principal
source of dioxin or TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) detected during
this study and that remediation measures should be implemented immediately to “... protect Vietnamese living in the
vicinity of such hot spots from further contamination and associated health
impacts.” On the contrary, they
confirm that significant sources of dioxins, i.e. dioxin and dioxin-like
compounds, do exist and may possibly pose greater risks for the environment and
population in the vicinity of the Da Nang Airbase. Important findings and associated comments
from our review of the Da Nang Report are briefly described below.
1.
The
Da Nang Report concludes that “There is
no doubt that historical use of the Da Nang Airbase by the US military and
their Operation Ranch Hand has resulted in significant dioxin contamination in
the environment and human population of Da Nang. Contamination was widespread during the
US-Vietnam war period, particularly in waterbodies and agricultural areas north
of the Airbase.”
Recently
unclassified documents indicate that damages to trees and vegetable crops in
the vicinity of the Da Nang Airbase occurred in September and October 1968 due
to widespread distribution of empty 55-gallon drums containing up to 3 gallons
of residues. No damages in the
agricultural areas north of the Airbase were reported. The problems were recognized and addressed in
March 1969.
2.
The
Da Nang Report concludes that “Chemical
analyses performed in this study confirm that the main source of dioxin
contamination at Da Nang Airbase was Agent Orange and other dioxin-contaminated
herbicides.”
This
conclusion appears to contradict with another conclusion stating that “Other contaminants (including
polychlorinated biphenyls [PCBs], organochlorine pesticides and hydrocarbons)
were also shown to be present in the environment, both inside and outside the
perimeter of Da Nang Airbase.” This
means that other sources of dioxin and dioxin-like compounds do exist both
inside and outside the perimeter of the Da Nang Airbase. At some sampling locations, most of the total
toxicity equivalent (TEQ) concentration detected is not TCDD.
3.
The
Da Nang Report concludes that “The
maximum soil TEQ concentration recorded in this study was 365,000 ppt [parts
per trillion]... represents extremely high contamination, and confirms Da Nang
Airbase as a significant ‘hot spot’.”
The
TEQ concentrations of the samples, particularly those collected from the former
Agent Orange Mixing and Loading Area (MLA) and the former Storage Area (SA), do
not appear to be consistent with their proximity and distribution. For example, the samples 06VN063 and 06VN065
are approximately 20 m from the sample 06VN058, but their TEQ concentrations
vary unexpectedly. The TEQ concentration
of 06VN058 is 365,000 ppt while the TEQ concentrations of 06VN063 and 06VN065
are 1,200 ppt and 27,900 ppt, respectively.
4.
The
Da Nang Report concludes that “Soil
dioxin levels from this study confirm contamination data previously obtained by
the Vietnamese Government and US EPA [United States Environmental Protection
Agency] (unpublished data).”
During
a meeting in Ha Noi on July 12, 2006, Committe 33 informed that the Da Nang
Airbase is the most contaminated hot spot in Vietnam with an average soil
concentration of 10,000 ppt TEQ. This is
significant different than the average concentration of 9 samples collected
from the MLA (approximately 106,000 ppt TEQ) and of 9 samples collected from
the SA (approximately 27,000 ppt).
5.
The
Da Nang Report concludes that “This study
(and previous studies conducted by Hatfield/10-80 Division of the Ministry of
Health [1998, 2000, 2003, 2005]) has verified that the highest concentrations
of Agent Orange dioxin in soil/sediments in Viet Nam are found in the top 10 cm
layer; some contaminations is found at deeper strata (e.g., > 30 cm), but
only in limited areas on the former Mixing and Loading Area and former Storage
Area at Da Nang Airbase (Figure 3.4, Figure 3.5, Figure 3.7).”
The
fact that dioxin has been found at highest concentrations in the top 10 cm
layer and at significant lower concentrations at deeper strata suggests that
its sources are relatively recent because Agent Orange dioxin was probably
washed away by decades of runoff.
6.
The
Da Nang Report concludes that “The human
population of Da Nang is therefore exposed to dioxin from contaminated food,
and likely also absorbs dioxin through the skin as a result of direct exposure
to contaminated soils and sediments (and possibly contaminated dust).”
This
conclusion contradicts with other conclusions stating that “At present, it is believed that only small proportion of the general
population of Da Nang City is adversely affected” (22 Airbase workers in
approximately 750,000 residents of Da Nang City), and that “The major run-off from the Da Nang Airbase hot spots appears to settle
in Sen Lake, and likely does not adversely impact the environment outside the
northern end of the Airbase.”
7.
The
Da Nang Report concludes that “The
highest TCDD level was recorded in a 42-year-old male who has lived and
consumed fish from the Sen Lake since 1990.
His TCDD level was 1,150 ppt TCDD (1,220 ppt TEQ; 94% TCDD), indicating
Agent Orange as the source of the TCDD contamination,” and that “The high levels of TCDD contributed almost
all of the total toxicity of the samples analyzed, indicating that Agent Orange
was the principal source of this dioxin congener.”
These
conclusions appear to be questionable because of the presence of other
dioxin-like compounds such as polychlorinated dibenzo-p-dioxins (PCDDs),
polychlorinated dibenzofurans (PCDFs), and PCBs. PCDDs, PCDFs, and PCBs must come from sources
other than Agent Orange, and these sources may contain TCDD. Analytical results from this study indicate
that these sources may be significant.
For example, the TCDD level in a blood sample from a West Airbase worker
(06VNB059) is 150 ppt TEQ while its PCBs level reaches 279 ppt TEQ. The breast milk sample (06VN201M) contains
only 14% TCDD of its 47.2 ppt TEQ (6.76 ppt) while its PCBs level reaches 13.6
ppt TEQ, which exceeds the World Health Organization and Canadian standards.
8.
The
Da Nang Report recommends that “Further research,
health studies, community education programs and exposure studies are required
at Da Nang to verify the extent of the exposure, and to protect populations
from further dioxin contamination.
Similar studies should be conducted at other dioxin hot spots in Viet
Nam, particular Bien Hoa. This is
consistent with the recommendations of ATSDR [Agency for Toxic Substances and
Disease Registry] (1997) for areas where soils levels are ≥ 1,000 ppt TEQ.”
We
agree that further research, health studies, community education programs and
exposure studies should be conducted, but these activities should focus on
unknown sources of dioxins such as PCBs and other toxic contaminants such as heavy
metals and pesticides. The contamination
at the Da Nang Airbase has been limited in a small area located within a highly
restricted area, i.e. a military zone; therefore, its potential risks appear to
be significantly less than those from the unknown sources.
It
is not clear if the ATSDR guidelines were properly followed for the DDAMP. In fact, none of the soil/sediment samples
collected during a study in 2005 by Hatfield exceeded 275 ppt TEQ. Even if the dioxin concentrations in soils
exceed 1,000 ppt TEQ, a contamination site must be evaluated by a health assessor
to determine if it is a public health hazard.
The evaluation must address the following questions:
v
How
extensive is the contamination?
v
Is
the contamination isolated or widespread?
v
Is
the contamination in surface soil or areas easily accessible to children or
adults? Is it in areas with no vegetation or in any other areas?
v
At
this site, how often (daily, weekly, monthly) and for what length of time
(months, years, or lifetimes) would exposures be likely to occur?
The
Da Nang Airbase site does not appear to pass this evaluation.
9.
The
Da Nang Report recommends that “Fishing
activities and lotus harvesting on all natural waterbodies on Da Nang Airbase (Sen
Lake, Lake B, and Lake C) should be terminated immediately.... A secure, more
permanent fence around the perimeter of the Airbase, particularly at the
northern border, is required to prevent access... And alternate livelihoods
need to be developed for those individuals who currently earn their living from
harvesting fish, lotus and other aquatic organisms and vegetables from Da Nang
Airbase.”
We
completely agree with these recommendations.
10.
The
Da Nang Report recommends that “Individuals
sampled for blood and breast milk in this study should be provided with a
report on the results of dioxin analyses performed (all donors requested that
their results be reported to them,” and that “Detailed human health assessments should be considered in selected
areas of Da Nang City to assess the extent of past exposure to herbicides and
to ensure no long-term effects of exposure occurs.”
Additional
medical examination may be conducted on all individuals who donated the blood
and breast milk samples for this study, and probably their off springs, to evaluate
potential health effects of the dioxin contamination. Detailed human health assessments may be
considered to assess the extent of the exposure, not only to herbicides (Agent
Orange) but also to other toxic contaminants such as PCBs, heavy metals, and
pesticides.
11.
The
Da Nang Report recommends that “Engineered
solutions for hot spots identified at the former Mixing and Loading Area and
former Storage Area need to be refined and implemented as soon as possible to
prevent further transport of contaminated soil and sediment into the general
environment at Da Nang.”
According
to the Da Nang Report, “... the major
run-off from the Da Nang Airbase hot spots appears to settle in Sen Lake, and
likely does not adversely impact the environment outside the northern end of
the Airbase;” therefore, engineered solutions for the hot spots at the
former Mixing and Loading Area and former Storage Area may not be
necessary. As a precautionary action, however,
these areas may be covered or paved by impervious materials to prevent
additional run-off from these hot spots.
12.
The
Da Nang Report recommends that “A
systematic review should be undertaken at Bien Hoa, Phu Cat and other Ranch
Hand sites in southern Viet Nam, where Agent Orange was used on site. In addition, a full investigation needs to be
carried out of ARVN bases where Agent Orange spray planes and helicopters were
loaded and serviced.”
It
is not clear why a systematic review is recommended for the Phu Cat
Airbase. According to the document No. 5612/BCĐ
33-VPBCĐ33 issued by Committee 33 on October 22, 2006, effects of Agent
Orange are not observed in the Phu Cat area.
We hope these findings and comments
would help solve the dioxins contamination problem in Vietnam more effectively
and efficiently. We also hope Ford
Foundation will expand its financial support to other vital problems such as
contamination of surface water and groundwater, especially in rural areas, and
management of municipal and industrial wastes.
As long as Vietnam continues to face with these problems, her future appears
to be uncertain.
We thank you for your attention and
consideration. If you have any questions
or desire additional information regarding this subject, please do not hesitate
to let us know.
Sincerely
yours,


Quang
M. Nguyen, P.E.
President
Vietnamese
American Science and Technology Society
cc: Ford Foundation, Office for Viet Nam
& Thailand
Hatfield Consultants