Alvin L. Young

Environmental fate and bioavailability of agent orange and its associated dioxin during the vietnam war

BackgroundIn 1996, the Committee on the Assessment of Wartime Exposure to Herbicides in Vietnam of the National Academy of Sciences’ Institute of Medicine (IOM) issued a report on an exposure model for use in epidemiological studies of Vietnam veterans. This exposure model would consider troop locations based on military records; aerial spray mission data; estimated ground spraying activity; estimated exposure opportunity factors; military indications for herbicide use; and considerations of the composition and environmental fate of herbicides, including changes in the TCDD content of the herbicides over time, the persistence of TCDD and herbicides in the environment, and the degree of likely penetration of the herbicides into the ground. When the final report of the IOM Committee was released in October 2003, several components of the exposure model envisioned by the Committee were not addressed. These components included the environmental fate of the herbicides, including changes in the TCDD content over time, the persistence of TCDD and herbicides in the environment, and the degree of likely penetration of herbicides into the ground. This paper is intended to help investigators understand better the fate and transport of herbicides and TCDD from spray missions, particularly in performing epidemiological studies.MethodsThis paper reviews the published scientific literature related to the environmental fate of Agent Orange and the contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and discusses how this affected the potential exposure to TCDD of ground troops in Vietnam. Specifically, the mechanisms of dissipation and degradation as they relate to environmental distribution and bioavailability are addressed.ResultsThe evaluation of the spray systems used to disseminate herbicides in Vietnam showed that they were capable of highly precise applications both in terms of concentrations sprayed and area treated. Research on tropical forest canopies with leaf area indices (a measure of foliage density) from 2 to 5 indicated that the amount of herbicide and associated TCDD reaching the forest floor would have been between 1 and 6% of the total aerial spray. Studies of the properties of plant surface waxes of the cuticle layer suggested that Agent Orange, including the TCDD, would have dried (i.e., be absorbed into the wax layer of the plant cuticle) upon spraying within minutes and could not be physically dislodged. Studies of Agent Orange and the associated TCDD on both leaf and soil surface have demonstrated that photolysis by sunlight would have rapidly decreased the concentration of TCDD, and this process continued in shade. Studies of ‘dislodgeable foliar residues’ (DFR, the fraction of a substance that is available for cutaneous uptake from the plant leaves) showed that only 8% of the DFR was present 1 hr after application. This dropped to 1% of the total 24 hrs after application. Studies with human volunteers confirmed that after 2 hrs of saturated contact with bare skin, only 0.15–0.46% of 2,4,5-T, one of the phenoxy acetic acid compounds that was an active ingredient of Agent Orange, entered the body and was eliminated in the urine.ConclusionsThe prospect of exposure to TCDD from Agent Orange in ground troops in Vietnam seems unlikely in light of the environmental dissipation of TCDD, little bioavailability, and the properties of the herbicides and circumstances of application that occurred. Photochemical degradation of TCDD and limited bioavailability of any residual TCDD present in soil or on vegetation suggest that dioxin concentrations in ground troops who served in Vietnam would have been small and indistinguishable from background levels even if they had been in recently treated areas. Laboratory and field data reported in the literature provide compelling evidence on the fate and dislodge-ability of herbicide and TCDD in the environment. This evidence of the environmental fate and poor bioavailability of TCDD from Agent Orange is consistent with the observation of little or no exposure in the veterans who served in Vietnam. Appreciable accumulation of TCDD in veterans would have required repeated long-term direct skin contact of the type experienced by United States (US) Air Force RANCH HAND and US Army Chemical Corps personnel who handled or otherwise had direct contact with liquid herbicide, not from incidental exposure under field conditions where Agent Orange had been sprayed.

Assessing possible exposures of ground troops to agent orange during the vietnam War: The use of contemporary military records

BackgroundPotential exposure of ground troops in Vietnam to Agent Orange and 2,3,7,8-tetrachIorodibenzo-p-dioxin (TCDD) remains controversial despite the passage of 30 years since the Vietnam War. Because of uncertainty over the serum dioxin levels in ground troops at the end of their service in Vietnam, attempts have been made to develop a methodology for characterizing exposure of ground troops in Vietnam to Agent Orange and other herbicides based upon historical reconstruction from military records. Historical information is often useful in evaluating and modeling exposure, but such information should be reasonably accurate, complete, and reliable.MethodsThis paper reviews the procedures and supporting historical information related to the spraying of herbicides in Vietnam. The historical information is classified into two categories: procedural information and operational information. Procedural information covered the process and procedures followed in spraying herbicides from US Air Force fixed wing aircraft (Operation RANCH HAND) in Vietnam, and included approval procedures for spray missions, the criteria required to conduct a mission, the control exercised by the Forward Air Controller and the Tactical Air Control Center and the characteristics of the equipment used to apply the herbicides. Operational information includes data from the RANCH HAND Daily Air Activities Reports, which included geographic locations of specific spray missions, the amount of herbicide sprayed by a specific mission, reports of battle damage to spray aircraft, reports of fighter aircraft support for aerial spray missions, and any comments, such as reasons for canceling a mission.ResultsHistorical information demonstrates that herbicide spray missions were carefully planned and that spraying only occurred when friendly forces were not located in the target area. RANCH HAND spray missions were either not approved or cancelled if approved when there were friendly forces in the area designated for spraying. Stringent criteria had to be met before spray missions could be approved. The operational information shows that spray missions for both defoliation and crop destruction were conducted in an extremely hostile environment. Heavy ‘fighter suppression’ with antipersonnel ordnance was used to minimize the impact of hostile ground fire on RANCH HAND aircraft. Procedures were in place that prohibited movement of troops into sprayed areas immediately after a mission due to the possible presence of unexploded ordnance delivered by fighter aircraft supporting RANCH HAND missions. The optimal nature of the spray equipment and application procedures minimized the possibility of significant spray drift.ConclusionsFew friendly troops were sprayed by fixed wing aircraft during Operation RANCH HAND, which delivered 95% of all defoliants used in Vietnam. Similarly, few troops were sprayed during helicopter or surface-based spray operations, which constituted the remaining 5 % of defoliants. Detailed policies and procedures for approval and execution of spray missions ensured that friendly forces were not located in the areas targeted for spraying. Fighter aircraft assigned to accompany each spray mission frequently suppressed much of the hostile fire with bombs and other ordnance. Confirmed clearance of the target area was necessary to avoid friendly casualties. Historical records establish that these policies and procedures were strictly followed. Exposure of troops whether from direct spraying or movement through areas recently sprayed was very unlikely.The wartime military records of troop positions and herbicide operations are valuable for some purposes, but have specific limitations in exposure reconstruction. The completeness and accuracy of the geographic data (maps used by RANCH HAND and military ground units) were dependent upon the inherent precision of the map, the accuracy with which it depicted surface features, and the completeness and accuracy of the information on which it is based. Navigation by the crew using visual orientation and reference to the map was the only means that aircrew on spray missions had for establishing their locations. A Forward Air Controller independent of Operation RANCH HAND was present at the location of each spray target immediately before and during spraying operations to verify the target location and ensure that friendly forces were clear of the target area. Anecdotal reports of direct spraying of troops in Vietnam likely reflect the RANCH HAND missions spraying insecticide for mosquito control at regular intervals from March 1967 through February 1972.OutlookThe distribution and levels of serum dioxin in RANCH HAND veterans and the US Army Chemical Corps Vietnam veterans (the unit responsible for helicopter and ground-based spray operations) are distinguishable from typical levels in the population decades after the Vietnam conflict. An exposure model similar to that proposed in the 2003 report of the Institute of Medicine’s Committee on ‘Characterizing Exposure of Veterans to Agent Orange and Other Herbicides Used in Vietnam’ was tested in 1988 by the Centers for Disease Control and Prevention and found to be a poor predictor of absorbed dose of TCDD. Military records during the Vietnam War lack the precision to determine that troops were directly sprayed with herbicides during Operation RANCH HAND, especially given the procedures in place to ensure clearance of friendly forces from the target area and the lack of elevated serum levels of TCDD in ground troops judged to have operated in heavily sprayed areas.

TCDD Biomonitoring and exposure to agent orange: Still the gold standard

to re-evaluate the issue in light of these new publications,and our work will be presented in a series of articles andcommentaries in forthcoming issues of ESPR (see the over-view on p. 146). My conclusion is that the IOM Commit-tees approach to exposure assessment is ill conceived, andfundamentally flawed. Serum dioxin analysis remains thegold standard, and the failure to validate the model ulti-mately endorsed by IOM should have led the IOM commit-tee to question the validity of the methodology rather thanto drop serum dioxin analysis from the project.Numerous studies relying on extensive serum dioxin testinghave established that some RANCH HAND (the Air Forceunit responsible for spraying herbicide from fixed-wing air-craft) and the US Army Chemical Corps veterans involvedin the application of Agent Orange in Vietnam had absorbeddoses of dioxin that can still be distinguished decades after-wards [5,6]. Similar studies of ground troops have not foundelevated levels of dioxin – strong evidence that these troopswere not significantly exposed to dioxin in Agent Orange[7]. The following summary of studies of biomonitoring ofdioxin levels from Agent Orange exposure, and the broaderpublic policy context, will provide an introduction to theissues to be addressed in detail in forthcoming papers.

Finding the balance between food and biofuels.

Over the years, Environmental Science and Pollution Research and her sister journal, The International Journal of Life Cycle Assessment have followed the development of industrial biotechnology, the development of the biobased industries, and the sources, application and distribution of biobased fuels (Young 2003, 2004; Gaugitsch 2004; Kloverpris et al. 2008; Halleux et al. 2008). Biobased resources are defined as source materials derived from a range of plant systems, primarily agricultural crops, forestry products, and processing streams (including microbial) in the food, feed, and fiber industries (Young 2003). The global emergence in interest of biobased products has been a result of the timely coalescence of economic considerations, environmental concerns, and scientific advancements. There were concerns for finding sustainable resources sufficient to build a biobased economy to replace a petroleum-based economy, developing new energy sources to curb climate change, and taking advantages of the advancements in the science of biotechnology and the elucidation of the genomes of plants and animals (Young 2003). A revolution in agriculture has been occurring. In the past two decades much has been written about the changes required to feed a future world population of 10 billion or more. Having food is only part of the demand; there has been much less focus on the material needs of such a population. Accompanying any population growth are the legitimate desires for adequate energy, transportation, housing, schools, health care, communication networks, and employment (Young 2003, 2004; Gaugitsch 2004). A petroleum-based economy has provided those needs, but there is a limit to the reserves of petroleum-based hydrocarbons. Switching to the use of renewable resources is a more responsible approach. However, the term ‘sustainability’ has become the popular buzzword to mean the better use of our limited resources to develop more environmentally sound industries and products, and to improve health and quality of life. But how does a global society become sustainable, when with limited arable land so many of the world’s largest growing populations, e.g., in China, India, and many of the underdeveloped countries of Africa, face the challenges of increasing agricultural productivity for the needs of food, feed, and fuels? Recent aggressive renewable energy policies have promoted a rapidly growing biofuels industry (Johnston et al. 2009). In Europe and in the United States this has resulted in the depletion of surplus agricultural feedstocks, thus contributing to commodity price increases of biofuel crops such as corn, soybean and rapeseed (Johnston et al. 2009). As noted by Kloverpris et al. (2008), the increasing production of first generation biofuels such as biodiesel and bioethanol has lead to an increasing demand for crops that can only be satisfied by cultivation of more land and/or the intensification of existing crop production. Thus, during this past year, the debate about food versus biofuels surfaced. Pointing to a global food crisis, international relief organizations joined food producers and food processors in seeking elimination of government programs to encourage biofuels, particularly corn-kernel based ethanol (Johnson 2008). Some reporters claimed that biofuels caused the food crisis, by circulating reports that: “Biofuels have forced global food prices up by 75%—far more than previously Environ Sci Pollut Res (2009) 16:117–119 DOI 10.1007/s11356-009-0106-8

Long Overlooked Historical Information on Agent Orange and TCDD Following Massive Applications of 2,4,5-T-Containing Herbicides, Eglin Air Force Base, Florida

BackgroundFrom 1961-1971, The Air Development Test Center, Eglin Air Force Base (AFB), Florida, developed, tested, and calibrated the aerial spray systems used in support of Operation RANCH HAND and the US Army Chemical Corps in Vietnam. Twenty major test and evaluation projects of aerial spray equipment were conducted on four fully instrumented test grids, each uniquely arrayed to match the needs of fixed-wing, helicopter, or jet aircraft. Each of the grids was established within the boundary of Test Area 52A of the Eglin Reservation.MethodsThe tests, conducted under climatic and environmental conditions similar to those in Vietnam, included the use of the military herbicides (Agents) Orange, Purple, White, and Blue. Approximately 75,000 kg of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 76,000 kg of 2,4-dichlorophenoxyacetic acid (2,4-D) were aerially disseminated on an area of less than 3 km2 during the period 1962-1970. Data from the analysis of archived samples suggested that an estimated 3.1 kg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), present as a contaminant, were aerially released in the test area. Because most of the vegetation had been removed before establishing the test site in 1961, there was an opportunity to follow ground-based residues independent of canopy interception, and the resulting high solar exposure of initial residues. Studies of the soils, fauna, flora, and aquatic ecosystems of the test grids and associated perimeters of Test Area C-52A (an area totally more than 8 km2) were initiated in 1969 and concluded in 1984.Results and DiscussionData from soil samples collected from 1974 through 1984 suggested that less than one percent of the TCDD that was present in soil when sampling began persisted through the ten-year period of sampling. More than 340 species of organisms were observed and identified within the test area. More than 300 biological samples were analyzed for TCDD and detectable residues were found in 16 of 45 species examined. Examination of the ecological niches of the species containing TCDD residues suggested each was in close contact with contaminated soil. Indepth field studies, including anatomical, histological and ultrastructural examinations, spanning more than 50 generations of the Beachmouse,Peromyscus polionotus, demonstrated that continual exposure to soil concentrations of 0.1 to 1.5 parts-per-billion (ng/g) of TCDD, had minimal effects upon the health and reproduction of this species.ConclusionsSince Agent Orange with its associated TCDD contaminant was aerially disseminated on the test grids, Test Area C-52A provided a ‘field laboratory’ for what may hae happened in Vietnam, had there been no intercepting forest cover. However, in Vietnam a ‘typical’ mission would have disseminated 14.8 kg of 2,4,5-T/ha, most of which was intercepted by the forest canopy, versus the 876 kg 2,4,5-T/ha on the test grid at Eglin. Moreover, each hectare on the Eglin test grid received at least 1,300 times more TCDD than a hectare sprayed with Agent Orange in Vietnam. The disappearance or persistence of TCDD is dependent upon how it enters the ecosystem. Spray equipment test and evaluations missions at Eglin were generally scheduled and conducted with environmental conditions that were optimal for spray operations. This suggests that conditions favorable for dissemination of herbicide were the same conditions favorable for photodegradation of TCDD. It was likely that 99 percent of the TCDD never persisted beyond the day of application. No long-term adverse ecological effects were documented in these studies despite the massive quantities of herbicides and TCDD that were applied to the site. Reviews by the US Environmental Protection Agency and the National Academy of Sciences’ Institute of Medicine did not address the fate of Agent Orange and TCDD as described in these studies from Eglin AFB, Florida.

Assessment of potential exposure to agent orange and its associated TCDD

1 Institute for Science and Public Policy, The University of Oklahoma, Norman, Oklahoma, USA 2 Department of Zoology, National Food Safety and Toxicology Center and Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA 3 Department of Forest Science, Oregon State University, Corvallis, Oregon, USA 4 Department of History, The Ohio State University, Columbus, Ohio, USA 5 Historian and Archivist, The RANCH HAND Vietnam Association, Fort Walton Beach, Florida, USA

The story of 2,4,5-t: A case study of science and societal concerns

In 1969, the American Association for the Advancement of Science (AAAS) asked Professor Matthew Meselson of Harvard University to develop a study of the use of herbicides in Vietnam. From this evolved the Herbicides Assessments Commission (HAC) led by Arthur Westing of Windham College [5], with a budget of

ESPR´s Total Environment

80,000, an absurdly small amount for a definitive study. HAC focused on maternity records in South Vietnam, but also included crop destruction, food chain, tropical forests and other topics. The Commissions results were widely reported in the popular press, especially the potentially negative effects on human reproduction and forest devastation, and created widespread fears about the irreversible damage to both humans and the ecosystem. Their findings did not appear in the scientific literature, as far as we know.

Bioassay versus chemical analysis for chemical residues in soil: the eglin air force base experience

1 Dept. of Zoology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany (Hollert@uni-heidelberg.de) 2 Department of Zoology, National Food Safety & Toxicology Center, Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824 USA (mhecker@entrix.com) 3 Humboldt University at Berlin, Institute of Biology, Arboretum, Freshwater and Stress Ecology, Spathstrase 80/81, 12437 Berlin, Germany (christian_ew_steinberg@web.de) 4 Visiting Professor, Institute for Science and Public Policy, Sarkeys Energy Center, The University of Oklahoma, Norman, Oklahoma, USA (youngrisk@aol.com)

The realignment and reorganization of ESPR

ConclusionThe analysis of soil residues by the use of bioassays and chemical analyses provided an insight into the nature of the chemical residues that persisted after the termination of the spray equipment test program in July 1970. The application of both methods proved valuable in deciding how to proceed with the environmental and ecological studies of the test site. Indeed these studies provided the foundation for the subsequent 15 years of scientific investigations of Test Area C-52. Fig 4. is an overview of the subsequent studies that occurred after the bioassay and chemical studies in 1969-1970. The Eglin Experience represents one the few available ‘classic studies’ of an entire ecosystem that has been massively contaminated with chemicals (in this case, herbicides) and followed for decades after the contamination [1].