From: | CPEO Moderator <cpeo@cpeo.org> |
Date: | 18 Nov 2002 16:29:10 -0000 |
Reply: | cpeo-military |
Subject: | [CPEO-MEF] APGSCC letter to Governor-Elect Ehrlich |
[Maryland] A copy of the following letter was sent to Governor-Elect Robert Ehrlich by Glenda Bowling <gbowling@comcast.net>, President of the APGSCC (Aberdeen Proving Ground Superfund Citizens Coalition). Please note that copies of the "Perchlorate Fact Sheet" and the "Technical Basis for the1 ppb Treatment Standard" are pasted immediately following the letter. _________________________________ November 12, 2002 Robert Ehrlich Governor-Elect 315 Cannon House Office Building Washington, D. C. 20515 Dear Governor-Elect Ehrlich: Congratulations on your election as Governor of the State of Maryland. For more than a decade, the members of Aberdeen Proving Ground Superfund Citizens Coalition (APGSCC) have worked closely with Aberdeen Proving Ground (APG), EPA Region III and Maryland Department of the Environment to represent community stakeholders in the cleanup of Superfund sites at APG. Our efforts have recently been focused on perchlorate contamination in the drinking water wells in Aberdeen. We think this issue is of highest importance, therefore we are supplying you with this briefing packet, so that you will understand the community perspective of the perchlorate contamination and the risks engendered by this contamination. The chemical perchlorate has been detected in seven of the eleven City of Aberdeen Production (CAP) wells that straddle the Aberdeen Area boundary of APG in Maryland. Since July 2002 the detected concentrations in the wells have ranged from 0.55 to 5 ppb. Although the concentrations of perchlorate in the finished water do not currently exceed the State of Maryland health advisory limit of 1 ppb (1), there is now clear evidence that there is perchlorate in the finished water at concentrations ranging from 0.61 to 1 ppb. Detections within the well field range from 5 ? 14 ppb, therefore we expect concentrations within the CAP wells to rise. We at APGSCC believe that there is a growing consensus that sufficient scientific data exists to justify immediate action to protect human health. We are now concerned that the delay in action will result in unnecessary human exposures. Please refer to the attached APGSCC Community Update, Perchlorate Fact Sheet for additional information regarding perchlorate toxicity [*PASTED BELOW]. The perchlorate is from historic and current training activities in the vicinity of Camp Stanton, Aberdeen Proving Ground, although no single incident or source location can be pinpointed. Given the complexity of the aquifer in the Aberdeen Area and the extent of the contamination it is difficult to predict if and when well concentrations will increase. Thus, we are faced with a completed exposure pathway and are relying solely on dilution to protect the health of local citizens. APGSCC believes this is unacceptable. Despite consensus at the local level that the perchlorate issue must be addressed, it is the current policy of the Department of Defense to oppose action to remediate perchlorate contamination in the absence of enforceable standards (2). Both EPA Region III and the state of Maryland are reviewing options to insure that APG addresses this contamination. We have specifically recommended the implementation of an emergency interim remedial action. This action must include the installation of temporary, portable treatment systems on each CAP well containing perchlorate contamination. This should be followed by the installation of a permanent treatment system to treat all CAP wells. We have petitioned both EPA and the State to use the regulatory powers established by CERCLA and SDWA to require APG to undertake an immediate interim remedial action. Based on our close working relationship with APG, we know that they want to take action, however, DoD will not permit them to do so. Such action would serve to ensure the protection of public health. The EPA and MDE have been reviewing enforcement options for over a month. While we appreciate that it is essential to produce the necessary legal justification for action in the administrative record, we are concerned that the delay in action is sending the wrong message to the DOD. More importantly, since the perchlorate is in the well field at much higher concentrations, each day that treatment is delayed increases the likelihood that residents will be exposed to unacceptable concentrations in their drinking water. The residents of the City of Aberdeen need your leadership in addressing this issue. APGSCC knows from experience that the delay in APG treating the solvent trichloroethylene in the adjacent Perryman aquifer resulted in unnecessary public exposures. We need to draw on the lessons learned by the Perryman experience and be more proactive in our response to this latest threat. Despite the contamination both the Aberdeen and Perryman well fields are extremely important groundwater resources. The recent drought has highlighted the need to protect these well fields, and insure that they continue to provide a safe, abundant source of drinking water for years to come. It is a fact of life that we must make risk-based decisions on a daily basis in the absence of complete scientific knowledge. In the case of perchlorate contamination in drinking water, there is strong scientific evidence to justify a 1 ppb treatment level. Please refer to the attached APGSCC Community Update on the Technical Basis for the 1 ppb Treatment Standard for more detailed information [**PASTED BELOW]. There are the national perchlorate issues, which are unfortunately, impacting the comparatively simple decision that needs to be made at APG. We urge you to focus on the needs of the city of Aberdeen and support the 1 ppb treatment standard. Thank you for your time and attention on this important matter. We look forward to discussing this issue further at your earliest convenience. I may be contacted at (...). APGSCC?s technical advisor, Dr. Cal Baier-Anderson, from the University of Maryland, Baltimore, can be reached at her home office, (...). Once again, congratulations on your election. We look forward to working closely with you and your administration over the four years. Sincerely, Glenda Bowling President, APGSCC 198 Sunnyside Drive Aberdeen, Maryland 21001 (1) Letter from Robert M. Summers, Director, Water Management Administration, Maryland Department of the Environment to Peter A. Dacey, City Manager, City of Aberdeen, Maryland, dated August 20, 2002. (2) Memorandum for Deputy Assistant Secretary of the Army (Environment, Safety, and Occupational Health) Deputy Assistant Secretary of the Navy (Environment) Deputy Assistant Secretary of the Air Force (Environment, Safety, and Occupational Health) Staff Director, Environment and Safety, Defense Logistics Agency Support Services (DSS-E). Subject: Interim Guidance on Sampling for Ammonium Perchlorate Contamination, Signed by John Paul Woodley, Jr., Assistant Deputy Under Secretary of Defense (Environment). CC: Donald S. Welch, EPA Region III, Regional Administrator Steven Hirsh, EPA Region III, Remedial Project Manager Frank Vavra, EPA Region III, Remedial Project Manager Richard F. Pecora, Secretary, Maryland Department of the Environment Richard Collins, Director, Hazardous Waste Division, Maryland Department of the Environment _____________________________________________ *Perchlorate Fact Sheet Prepared for APGSCC by Cal Baier-Anderson, PhD University of Maryland, Program in Toxicology November 2002 What is Perchlorate? According to the Army, perchlorate is used as a chemical oxidizer in propellants and rocket fuel. It is also found in smokes and in several pyrotechnic formulations. Perchlorate is very soluble in water, so once released to the environment, rapidly moves through the soil and into the groundwater. Since it is very stable, it can persist in groundwater for decades. At Aberdeen Proving Ground, perchlorate has been found in the vicinity of an active training area, both near and within the City of Aberdeen Production wells. Perchlorate is known to affect thyroid function in humans. Thyroid Function The thyroid secretes hormones, which influence many different body functions such as metabolism, growth, development and reproduction. Hormones are chemical messengers that circulate in the blood and influence the function of cells and tissues throughout the body. Perhaps the most noticeable effects of thyroid hormones are that they increase the body?s consumption of oxygen and generation of heat (increase metabolism). Resting heart rate and pumping capacity are increased, which promotes the delivery of oxygen throughout the body. Thyroid hormones influence growth and maturation in children; this is particularly evident in the growth and development of bones. Thyroid hormones are essential to the development of the central nervous system in fetuses, infants and children. If low hormone levels are present during gestation or at the time of birth and go untreated, severe, irreversible mental retardation can occur. Thyroid hormones also enhance wakefulness, alertness, awareness of hunger, memory and learning capacity. In adults, thyroid hormones play an important role in the regulation of reproduction. Deficiencies in thyroid hormones can lead to disruption of the production of eggs and sperm. Since hormones are powerful chemicals, their production must be regulated. When thyroid hormones (such as T3, tri-iodithyronine and T4, thyroxine) in the blood are low, the pituitary, which contains thyroid hormone sensors, makes thyroid stimulating hormone, or TSH. TSH is a chemical signal that acts on the thyroid to trigger the production and release of thyroid hormones. When the level of thyroid hormones in the blood is appropriate, then the pituitary stops producing TSH. In the absence of TSH, the thyroid ceases hormone production. Iodine and the Thyroid Iodine is required to make thyroid hormones. The thyroid cannot absorb iodine without the help of a transport system. The transport system is a protein that contains ?seats?; the iodine takes a seat on the transporter outside of the thyroid along with sodium. Once the ?seats? are filled, the transporter changes shape to bring the iodine and the sodium into the thyroid. The transporter that moves the iodine into the thyroid is called the iodine-sodium symporter. Once the iodine is inside the thyroid, it can be used to make thyroid hormones. While the ?seats? in the transporter are fairly specific for iodine and sodium, perchlorate can fit in the iodine ?seat?. In doing so, it prevents iodine from getting into the thyroid. Without the iodine, the thyroid cannot make thyroid hormones. Thyroid Responses In healthy adults the thyroid can compensate for short-term inhibition of iodine uptake since the thyroid can store hormones for months. In health adults exposed to perchlorate, the thyroid will release the stored hormones in response to TSH, thereby maintaining adequate circulating thyroid hormone levels. Once the stored hormones are depleted, the cells of the thyroid may respond to TSH by increasing in size (called hypertrophy) or increasing in number (called hyperplasia). By increasing cell size and number, the thyroid is trying to promote hormone production. Sustained stimulation of the thyroid by TSH, followed by hypertrophy and hyperplasia has been shown to lead to thyroid cancer. Possibly more important than the potential risk of cancer, which could require years of continued stimulation by TSH, the absence of thyroid hormones in the blood can result in non-cancer effects. Potential Toxicological Effects The main concerns are for the potential effects on fetuses, infants and children. There have been several recent studies of newborns in communities that are currently being exposed to perchlorate in their drinking water, yet the results are difficult to interpret, due to the many confounding factors (such as dietary iodine intake, differences in birth weight, gender and ethnicity). The most detailed study to date (Schwartz, 2001) found significant, dose-dependent decreases in T4 levels in newborns exposed to perchlorate. There have been several studies of the effects of perchlorate on iodine uptake in healthy human adults. Although there is evidence of transient decreases in iodine uptake during short-term perchlorate exposure, iodine uptake resumes once the exposure is stopped. Once again, since healthy adults can compensate for decreased iodine uptake in the short term, these results cannot be used to predict potential impacts on fetuses, which have no hormone storage capacity. Babies, children, or even adults suffering from other health problems may also be more sensitive to the toxic effects of perchlorate. Other studies suggest the potential for perchlorate to alter immune system function. Specifically, there seems to be an association between perchlorate exposure and skin rashes and white blood cell dysfunction as well as changes in blood cell counts, including the potentially deadly aplastic anemia. The relationship between perchlorate and immune system function is not well understood, and needs more research. There have been many studies on the effects of perchlorate on laboratory animals. It should be noted that the mechanism of toxicity in rats and humans ? the inhibition of iodine uptake into the thyroid - is the same. This is important, because it makes comparisons between laboratory animals and humans easier. The use of laboratory animals is advantageous because exposures and analyses can be conducted in a controlled environment, which cannot be done with humans. These studies help us to understand the specific impacts of perchlorate. In the laboratory animal studies, perchlorate causes a dose-dependent decrease in thyroid hormone production, and a dose-dependent increase in TSH production. Female rats seem to be more sensitive to perchlorate than male rats. Longer exposures result in increased thyroid size due to cellular hypertrophy and hyperplasia (increased cell size and number). One particular study demonstrated that exposure of pregnant rats to perchlorate resulted in size changes within specific regions of the brain in the pups. There is also an indication that perchlorate increases motor activity in rats. Safe Exposure Limits for Perchlorate The weight of evidence of the available studies leads the EPA to recommend a reference dose of 0.00003 mg/kg/day. The reference dose represents a conservative estimate of the maximum amount of a chemical, in this case perchlorate, to which we can be safely exposed. Since the main exposure route for perchlorate is via the drinking water, our concern is setting a safe limit for perchlorate in the drinking water. A reference dose of 0.00003 mg/kg/day translates into a limit of 1 micrograms/L in the drinking water. Recently, EPA Region 3 recommended an exposure limit of 1.0 micrograms/L in the Aberdeen drinking water. Maryland Department of the Environment issued a Health Advisory for perchlorate in the drinking water above 1.0 micrograms/L. We believe that based on the available scientific information this represents a reasonable limit that will be protective of the community. _________________________________________ **Technical Basis for the1 ppb Treatment Standard Prepared for APGSCC by Cal Baier-Anderson, PhD University of Maryland, Program in Toxicology November 2002 Setting a Standard: The MCL The US Environmental Protection Agency is tasked with setting standards for chemical contaminants in the drinking water. These standards, called Maximum Concentration Limits (MCL), are based on the toxicity of the chemicals. Not all chemicals are equally toxic: for instance, the MCL for the solvent trichloroethene is 5 ppb, while the MCL for vinyl chloride is 2 ppb and the MCL for toluene is 1000 ppb. The EPA is in the process of evaluating the data on perchlorate. The process of evaluating perchlorate toxicity will provide the foundation for setting the MCL. One of the first steps in developing the MCL is to determine the Lowest Observable Adverse Effect Level (LOAEL). The LOAEL for perchlorate is based on the following observations: perturbation in thyroid and pituitary hormones, thyroid cell changes and changes in brain size and shape. Based on a review of numerous laboratory studies, the EPA determined that the LOAEL for perchlorate is 0.01 mg/kg/day. This means that exposure to perchlorate at this level is likely to result in changes in thyroid and pituitary hormones, thyroid cell changes and brain size and shape. Since it is the goal to set a limit that will not result in adverse effects, safety factors are applied to this number to extrapolate from the LOAEL to the No Observable Adverse Effects Level (NOAEL). Additional safety factors must be applied to account for differences in response between individual humans, the increased sensitivity of the fetus in utero, and for database inadequacies. For instance, we know that perchlorate can affect immune system function, but we currently do not understand how this happens. The application of safety factors to the LOAEL is then used to calculate the Reference Dose (RfD). The reference dose is an exposure concentration that is expected to represent a safe level of exposure. In the revised draft toxicity assessment, which was released in January 2002 a reference dose of 0.00003 mg/kg/day was proposed for perchlorate. When it is assumed that all perchlorate exposures will come from drinking water (a reasonable assumption in the case of Aberdeen Proving Ground) the Risk Based Concentration (RBC) = 1.1 micrograms/L, which has been rounded down to 1 micrograms/L. (Note that micrograms/L = ppb.) Based on this information, the state of Maryland has set a Health Advisory Limit that indicates that when the drinking water supply is above 1 ppb, the consumers must be notified, and sensitive populations (defined as pregnant women, young children and people with hypothyroidism) should avoid drinking the water. Scientific Controversies Controversies surrounding the calculation of the RBC are based on the studies included in the analysis, the endpoints used to determine toxicity, and the application of factors to account for uncertainty. For example, a proposed 4 ppb exposure limit is based on the inhibition of iodide uptake by the thyroid as the endpoint. In contrast, the new endpoints described above - changes in thyroid and pituitary hormones, thyroid cells and brain size and shape - are directly linked to pathologies stemming from perchlorate exposure, and include the neurological effects. The state of Massachusetts used a different approach to calculating a limit for perchlorate in the drinking water. The 1.5 ppb exposure limit is based on inhibition of iodine uptake in children. US EPA and EPA Region III argue that since the most sensitive receptor is the fetus, then we must base exposure limits on consumption of water by adults (pregnant women). The state of California includes a human study (Greer, et al, Environmental Health Perspectives, September 2002) whereby healthy adults were given perchlorate for two weeks and the uptake of iodine was measured. Therefore this study used as an endpoint the uptake of iodine, as opposed to observed pathology. This study also makes the assumption that there is no thyroid deficiency in the US. The current proposed state Public Health Goal (PHG) is 6 ppb. A representative from the California Office of Environmental Health (Robert Howd) acknowledged that it is impossible to extrapolate potential exposure to the fetus based on this study. He also noted that the state is in the process of reassessing perchlorate toxicity, and while he could not reveal the likely outcome, he indicated that the new PHG is likely to be lower than the current PHG. The primary unanswered concerns are potential impacts on the developing fetus, infants and children. The thyroids of healthy adults contain several months worth of thyroid hormone; therefore healthy adults are relatively insensitive to short term perchlorate exposure. In contrast, the fetus does not have any storage capacity, so even short-term exposure to perchlorate can result in harm. There is evidence that perchlorate can accumulate in breast milk, posing a risk to nursing babies. These areas require more research to determine specific risks. Political Pressure used to Influence Interpretation of Science The Department of Defense and their defense contractors have unintentionally introduced perchlorate into the groundwater at sites all across the country. Particularly hard hit are groundwater resources in California and Nevada. The projected treatment costs may be estimated in the billions of dollars. Therefore the DOD is attempting to influence the interpretation of scientific data to justify a less stringent treatment standard. We are concerned that these political and economic concerns will prevent the scientists and risk assessors at EPA from doing their job. While cost may be a legitimate concern, it must be secondary to human health. It is important to note that it is simply not possible to wait until we have complete scientific knowledge before we make risk-based decisions. In our view, a national consensus is building in support of the 1 ppb treatment standard for perchlorate, with the understanding that this level will be protective of sensitive human receptors. We believe that it makes sense from a scientific perspective to advocate a Risk Based Concentration of 1 ppb for perchlorate at Aberdeen Proving Ground. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |
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