Appendix A



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Guidelines for Chemical Warfare Agents in Military Field Drinking Water Appendix A

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Guidelines for Chemical Warfare Agents in Military Field Drinking Water Criteria for Developing Field Drinking-Water Standards1 INTRODUCTION The U.S. Army in collaboration with the Lawrence Livermore National Laboratory developed drinking-water standards for several chemical warfare (CW) agent—organophosphorus nerve agents, cyanide, T-2 toxin, lewisite, sulfur mustard, and Agent BZ. In this chapter, the criteria used to develop the standards are presented (Daniels and Layton, 1988). The subcommittee considered these criteria in responding to its charge to review the Army's proposed field drinking-water standards. Based on its review of the proposed standards and the criteria used to develop the standards, the subcommittee concluded that the criteria used by the Army and Lawrence Livermore National Laboratory were adequate. However, some modifications were suggested. These suggestions are discussed in this appendix. CRITERIA FOR DEVELOPING FIELD DRINKING-WATER STANDARDS Drinking-water standards for CW agents are developed to prevent 1   This appendix primarily comprises modified excerpts from Daniels and Layton (1988).

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Guidelines for Chemical Warfare Agents in Military Field Drinking Water performance-degrading effects associated with (1) physical abilities of the sensory, neuromuscular, respiratory, gastrointestinal, cutaneous, and cardiovascular systems; (2) mental faculties related to properly functioning cognitive processes needed for reasoning and decision making; and (3) behavioral attributes involving control of emotions, discipline, motivation, morale, and cooperation (Daniels and Layton, 1988). Adverse effects can result from both the toxic properties and the poor quality of field water. Although the direct toxic effects of dissolved constituents are a primary concern in the development of guidelines, involuntary dehydration resulting from reduced consumption of poor-quality water is also a concern (Hubbard et al., 1982). The basic purpose of field drinking-water standards is to prevent decrements in the performance of military personnel with battlefield responsibilities. To develop field drinking-water guidelines for CW agents in a consistent fashion, the Army relied on the following set of criteria regarding the characteristics of the population at risk, water-consumption rates and exposure periods, data requirements, toxic effects, and uncertainty factors (Daniels and Layton, 1988). Characteristics of the Population at Risk The military personnel at risk are those deployed in the field. In general, these personnel are predominantly males who are between 18 and 55 years of age, weigh an average of 70 kg, and are in good health. Females performing noncombat activities in the field were also considered. In general, females are also between 18 and 55 years of age and in good health, but they weigh an average of 60 kg. The Army's recommended field drinking-water standards are intended to protect all military personnel, from infantryman to fighter pilot, against performance-degrading effects. The recommended standards are not applicable to populations of civilians and do not represent water-quality standards for drinking water treated at properly functioning fixed installations (Daniels and Layton, 1988). Water Consumption Rates and Exposure Periods The maximum individual daily amount of drinking water required by

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Guidelines for Chemical Warfare Agents in Military Field Drinking Water military personnel to remain combat effective can range from about 5 to 15 L/d, depending on climate, season, and intensity of work (Henry, 1985). The duration over which consumption of field water will take place is divided into three scenarios: (1) short-term consumption lasting up to 7 consecutive days, (2) long-term consumption exceeding 7 days and lasting up to 1 year, and (3) emergency situations when soldiers are cut off from supply lines and treated water is not available. In these situations, troops are trained to select the clearnest water available and treat it with field expedient methods (U.S. Army, 1990, pp. 4-5). No standards apply for emergencies. Short-term standards for field drinking water are needed because drinking water that meets long-term standards might not be available in some battlefield situations. However, in the opinion of U.S. military and civilian experts, access to drinking water meeting the long-term standards is unlikely to be denied for more than 7 consecutive days. Long-term standards for field drinking water are applicable to forces deployed in military situations lasting up to 1 year; in those situations, military personnel would obtain the greatest proportion of their drinking water from military water-purification equipment, such as the reverse osmosis water purification unit. The DOD concluded that a 1-year duration for long-term field drinking-water standards was sufficient. The rationale for this conclusion is that within a year most of the drinking water consumed by field personnel should be provided by properly functioning fixed installations (Daniels and Layton, 1988). The subcommittee 's charge was to consider “field” or “theater of operation” situations for time periods less than or equal to 7 days (i.e., short-term consumption). Objectives of Field Drinking-Water Standards The specific objectives of short- and long-term field drinking-water standards are defined by the Army (U.S. Army, 1986, 1990). These objectives are the cornerstone upon which the recommendations for field drinking-water standards are based (Daniels and Layton, 1988). Specifically, short-term standards are designed to protect against any health effect that can adversely affect the capability of an individual to conduct a military mission. However, as stated by the Army (U.S. Army, 1986), a field commander forced to institute short-term standards must acknowl-

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Guidelines for Chemical Warfare Agents in Military Field Drinking Water edge the potential for reduced combat efficiency each day that short-term standards remain in effect; the risk of morbidity from prolonged exposure to field drinking water meeting short-term standards is greater than that to field water meeting long-term standards. Alternatively, long-term standards are designed to protect against any adverse health effects that appear during a 1-year exposure period. In combat situations, long-term adverse health effects (e.g., carcinogenesis, developmental and reproductive effects, and latent or chronic effects) are typically not as imminent or as consequential as performance decrements induced by immediate (i.e., acute) health effects. Nevertheless, potential chronic effects are identified in discussions accompanying the subcommittee 's recommendations for guidelines if such information is available in the literature (Daniels and Layton, 1988). Data Requirements When possible, toxicological data on humans following oral exposure are evaluated to ascertain dose-response relationships. If such human data are sparse, inadequate, or nonexistent, dose-response relationships for humans are extrapolated from oral dose-response data for animals. However, other routes of exposure in humans and animals were also considered by the subcommittee. The health effects resulting from synergistic interactions between chemicals of military concern are usually not considered because of the paucity of relevant data. Toxic Effects Neither the existence or performance of water-quality monitoring devices nor the efficiency of water-purification equipment are a consideration in the development of the field drinking-water standards. The paramount concern is to develop and recommend standards that would prevent performance degradation from field drinking water consumed by military personnel deployed in field situations. Consequently, recommended standards do not protect against chronic health effects, such as carcinogenesis or developmental and reproductive effects (Daniels and

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Guidelines for Chemical Warfare Agents in Military Field Drinking Water Layton, 1988). Based on the available toxicological data, the Army identified no-observed-adverse-effect levels (NOAELs) or lowest-observed adverse-effect levels (LOAELs) for noncarcinogenic effects from studies in humans or animals. The highest NOAEL and LOAEL are identified for the most sensitive end point (target organ) and in the most sensitive species. When the literature did not contain NOAEL or LOAEL data, the Army used the available information, including data on the no-observed-effect level (NOEL) and the lowest-observed-effect level (LOEL). Uncertainty Factors The Army used an uncertainty factor of 10 for interspecies (animal-to-human) extrapolation. However, the Army did not use an uncertainty factor for intraspecies (human-to-human) extrapolation because it assumed that all military personnel are healthy and do not have preexisting health conditions. The Army did not address the use of modifying factors to account for inadequate data or lack of data on certain toxic end points. When the data were not sufficient to identify a NOAEL, the Army used a NOEL or LOAEL and applied an uncertainty factor of 10. MODIFICATIONS TO FIELD DRINKING-WATER STANDARDS The subcommittee reviewed the criteria used by the Army in deriving field drinking-water standards for CW agents. In general, these criteria are consistent with criteria used by EPA to develop drinking-water guidelines. Because the majority of the subcommittee agreed with the Army's criteria, it did not develop its own set of criteria as originally charged. However, certain modifications to the standards were suggested by the subcommittee. These modifications are discussed below and focus on the identification of concentrations at which critical toxicological effects occur. The subcommittee did not agree with the Army's proposed field drinking-water standards for several of the organophosphorus nerve

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Guidelines for Chemical Warfare Agents in Military Field Drinking Water agents—i.e., Agents GA, GB, GD, and VX. The drinking-water standards were based on 50% acetylcholinesterase (AChE) inhibition, which had been considered to be the NOEL. The subcommittee recommended 25% AChE inhibition as the NOEL for these substances. The subcommittee did not agree with the methods used by the Army to derive field drinking-water standards for sulfur mustard. The Army based its proposed standards for sulfur mustard on an acute LOEL of 300 µg/kg of body weight per day (Dacre and Burrows, 1988). This LOEL was identified as the concentration at which weight loss occurred in rats exposed to sulfur mustard for 90 days (Sasser et al., 1989). It was unclear to the subcommittee whether the weight loss was due to a toxic response or to reduced ingestion of food by experimental animals. The subcommittee did support consideration of 100 µg/kg/day as the NOEL, as used in the drinking-water analysis by Dacre and Burrows (1988). Furthermore, the procedure used by Dacre and Burrows to estimate the NOEL from data in the draft report by Sasser et al. (1989)—i.e., LOEL rating-effect value (RVe)—is an unsubstantiated procedure and not endorsed by EPA. The RVe is only used to calculate composite scores for determining reportable-quantity (RQ) estimates (EPA 1984). NOEL and LOEL values are to be already based on animal or human data from the literature. REFERENCES Dacre, J.C., and W.D. Burrows. 1988. Recommended Field Drinking Water Criteria for Chemical Agent Sulfur Mustard. Tech. Rep. 8816. U.S. Army Biomedical Research and Development Laboratory, Frederick, Md. Daniels, J.I., and D.W. Layton. 1988. Introduction. Pp. 1-1–1-10 in Evaluation of Military Field-Water Quality, Vol. 4, Part 1, J.I. Daniels, ed. Publ. No. AD UCRL-21008. Report prepared for the U.S. Army Medical Research and Development Command, Fort Detrick, Frederick, Md. EPA (U.S. Environmental Protection Agency). 1984. National Secondary Drinking Water Regulations. EPA 570/9-76-000. U.S. Environmental Protection Agency, Washington, D.C.

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Guidelines for Chemical Warfare Agents in Military Field Drinking Water Henry, C.D. 1985. Heat stress and its effects on illness and injury rates. Mil. Med. 150:326-329. Hubbard, R.W., M. Mager, and M. Kerstein. 1982. Water as a tactical weapon: A doctrine for preventing heat casualties . Pp. 125-139 in Army Science Conference Proceedings, June 1982, Vol. 2. U.S. Military Academy, West Point, N.Y. Sasser, L.B., R.A. Miller, D.R. Kalkwarf, R.L. Buschbom, and J.A. Cushing. 1989. Toxicology Studies on Lewisite and Sulfur Mustard Agents: Subchronic Toxicity of Sulfur Mustard (HD) in Rats. AD-A214-555, PNL-6870. Report prepared by Pacific Northwest Laboratory, Richland, Wash., for the U.S. Army Medical Research and Development Command, Fort Detrick, Frederick, Md. U.S. Army. 1986. Occupational and Environmental Health Sanitary Control and Surveillance of Field Water Supplies. Tech. Bull. No. TB MED 577. Department of the Army Headquarters, Washington, D.C. U.S. Army. 1990. Water Supply in Theaters of Operations. Field Manual 10-52 (FM 10-52). Department of the Army Headquarters, Washington, D.C.

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