PUBLIC HEALTH ASSESSMENT
LOCKHEED PROPULSION COMPANY
(a/k/a LOCKHEED MARTIN PROPULSION CORPORATION)
REDLANDS, SAN BERNARDINO COUNTY, CALIFORNIA
The Lockheed Martin Propulsion Corporation site is located at 1500 Crafton Avenue in Redlands, California. Lockheed was in operation between 1961 to 1974, as a research and production facility of solid fuel rockets and solid rocket propellant for the military. For years the facility disposed of hazardous waste, including perchlorate, which resulted in perchlorate contamination in the groundwater.
In 1997, perchlorate was discovered in a number of domestic water supply wells that serve several water purveyors throughout San Bernardino and Riverside counties. Two of the wells in the City of Loma Linda's municipal drinking water system had been impacted by the perchlorate groundwater plume, originating from the Lockheed site.
The California Department of Health Services (CDHS) has concluded that water distributed in the past and currently, by the City of Loma Linda, poses no public health hazard. Perchlorate has not been present at levels that would cause health effects. When more toxicological information about perchlorate becomes available, CDHS may update the toxicological evaluation for the Loma Linda system.
The purpose of this public health assessment is to review the groundwater data from municipal water supply wells used for the City of Loma Linda's domestic water supply, and to evaluate possible adverse health effects from exposure to perchlorate. Only the potential health impact caused by ingestion of perchlorate contaminated drinking water will be evaluated.
The Environmental Health Investigations Branch (EHIB) within the California Department of Health Services (CDHS), under a cooperative agreement with the Agency for Toxic Substance and Disease Registry (ATSDR), is conducting public health assessment activities relating to contamination originating from the Lockheed Martin Propulsion Corporation hazardous waste site in San Bernardino County, California. This public health assessment will focus on perchlorate contamination in the City of Loma Linda's drinking water supply.
Lockheed Propulsion Company began operations in 1961, after acquiring the site from Grand Central Rocket Company (GCRC), which began operations in 1954. The site consists of approximately 400 acres which was leased from the City of Redlands (Attachment: Figure 1). The GCRC facility was used for the production, testing and disposal of solid rocket propellant used in rocket engines. Lockheed used the facility for research and for production of solid fuel rockets for military and commercial use until 1974. Lockheed disposed of hazardous waste by open burning, discharge into evaporation and settling ponds, and inadvertent dumping . Some of these discharged hazardous waste, including perchlorate, entered the groundwater and migrated outside the boundaries of the Lockheed site . Perchlorate, in the form of ammonium perchlorate is used in the manufacture of solid rocket fuel, munitions, and pyrotechnics (fireworks).
In the 1980's, trichloroethylene (TCE), a solvent, was detected in four out of twelve groundwater wells sampled in the Redlands area. The Division of Drinking Water and Environmental Management (DDW) within the CDHS, directed that any drinking water wells which contained TCE at levels exceeding 5 parts per billion (ppb) or the maximum contaminant level (MCL), be taken off-line. In 1989, as a result of the TCE contamination, the California Regional Water Quality Control Board (CRWQCB), Santa Ana Region, and the Department of Toxic Substance Control (DTSC) provided funding for the installation of a Liquid Phase Granular Activated Carbon (GAC) groundwater treatment system to treat and clean the water from the TCE impacted wells . Subsequent investigations by the CRWQCB determined that Lockheed Martin Corporation (formerly Lockheed Propulsion Company) was the source of the TCE contamination . TCE had been the primary contaminant of concern emanating from the Lockheed site, until mid 1997 when the first tests for perchlorate in drinking water were performed.
In April 1997, the DDW-CDHS began sampling groundwater basins which were considered vulnerable to perchlorate. Historically, perchlorate has not been considered a common contaminant in groundwater. The expanded sampling conducted by the DDW was in response to perchlorate being found at levels of health concern in public water supply wells at another defense contractor facility in northern California.
In this public health assessment, we will focus on describing the perchlorate contamination that has reached the City of Loma Linda's public water supply and evaluate the health impact that may have occurred from exposure to perchlorate. Approximately seven water purveyors throughout San Bernardino and Riverside counties may have already been impacted by the perchlorate. Since the water sources and distribution of these water systems are different and complex, a separate public health assessment should be prepared evaluating each system. CDHS has already completed a health consultation evaluating the impact of perchlorate on the Victoria Farms Mutual Water Company system . This public health assessment is the second in the series that will address the impact of perchlorate contamination on municipal water supply wells. During this process, data and information on the release of hazardous substances and their impact to the public will be evaluated.
The City of Loma Linda Water Service Description
The City of Loma Linda is one of several water districts that receive water from aquifers within the Bunker Hill Groundwater Basin. The City of Loma Linda's water system has been impacted by the perchlorate contamination which originates from the Lockheed Martin site.
The City of Loma Linda's system supplies water to 3,869 connections, approximately 23,000 people, for residential and commercial use . The water supply system consists of six groundwater wells (5 active, 1 inactive), Mountain View No. 1, Mountain View No. 2, Richardson No. 1, Richardson No. 2, Richardson No. 3 and Nicks . The Mountain (Mt.) View well No. 1 was taken off-line in April 1998 due to rising perchlorate levels (Attachment: Table 1) . In addition, the Loma Linda system has connections with the City of Redlands and the City of San Bernardino's water systems for supplementary needs.
The City of Loma Linda wells draw water from different depths and aquifers. The Mt. View well No. 1 draws water from a depth of 750 feet. Mt. View well No. 2 draws water from a depth of 900 feet. The Mt. View wells No. 1 and No. 2 were blended at a 1:2 ratio, with Mt. View No. 2 producing twice as much water as Mt. View No. 1 . Richardson well No. 1 draws water from a depth of 1200 feet and is blended with water from Richardson well No. 2, which is drawn from a depth of 970 feet. Richardson well No. 3 draws water from a depth of 815 feet. The Nicks well draws water from a depth of 868 feet and is used for emergency backup during peak usage times . With the exception of supplementary water received from the City of Redlands, the Loma Linda system does not utilize any other surface-water sources for the drinking water supply .
In April 1997, the San Bernardino District field staff of the DDW began testing public water supply wells in areas where perchlorate contamination was suspected to exist . Because Lockheed used solid rocket fuel, the DDW field staff in the San Bernardino office sampled wells located to the west, and downgradient of the Lockheed facility, including five wells in the City of Loma Linda's municipal drinking water system. The well samples were analyzed by the CDHS Sanitation and Radiation Laboratory located in Los Angeles, with a quantification limit of 4 ppb. The CDHS provisional action level for perchlorate in drinking water is 18 ppb (based on USEPA's provisional reference dose and assuming a 70 kg person drinks 2 liters per day), at which the water purveyor would have to notify their water customers . Currently, there are animal studies underway which are looking at perchlorate toxicity; and as more toxicological data becomes available, a change in the provisional action level may occur (see Recommendations section, page 10).
In the April 1997 sampling, perchlorate was detected at the Mt. View No. 1 / Mtn. View No. 2 blend point (Lawton booster station) at a level of 7.6 ppb (Attachment: Table 1). Since this level did not exceed the CDHS provisional action level, regular monitoring of these wells was the course of action taken by the City of Loma Linda. Monitoring results for raw water (prior to blending and treatment) and finished water (after blending and treatment) samples are presented in the Table 1 and Table 2 at the end of this document. Levels of perchlorate in the Loma Linda system wells range from non-detect to 29 ppb, in raw water samples (Attachment: Table 1) . The highest level of perchlorate measured in finished water, was from the Mt. View blend, at a level of 9.6 ppb (Attachment: Table 2.). This level does not exceed the provisional action level for perchlorate of 18 ppb.
City of Loma Linda staff have estimated that the average level of perchlorate in finished water is 6 ppb to 8 ppb . The City of Loma Linda has not served drinking water to customers above the CDHS provisional action level of 18 ppb .
On May 28, 1997, DDW staff held a meeting with the water purveyors to inform them of the perchlorate contamination. DDW staff provided each water purveyor with the sampling results and health effects information relating to perchlorate exposure . Mt. View well No. 1 is the only well in the Loma Linda system that has shown consistent levels of perchlorate (prior to blending), above the provisional action level. This is most likely due to the fact that Mt. View No. 1 is the shallowest well (750 ft.) in the system (Attachment: Table 1). Perchlorate has been detected intermittently in the deeper Mt. View well No. 2 (900 ft.) and Richardson well No. 2 (970 ft.), which is an indication that the perchlorate plume is migrating downward into deeper aquifers (Attachment: Table 1). Richardson well No. 3 and the Nicks well have not been impacted by the perchlorate plume (Attachment: Figure 1 and Table 1). According to model data derived by Lockheed, which estimates the migration of the plume, the perchlorate should not impact the Richardson well No. 3 or the Nicks well .
TCE, a Lockheed site associated chemical, and dibromochloropropane (DBCP) a soil fumigant used in the citrus groves, have also been detected in the Loma Linda public water system at levels below the allowable drinking water standards or MCLs. DBCP is a contaminant commonly found in agricultural areas and is not associated with the Lockheed site. TCE has only been detected in the Loma Linda public water system (Mt.View well No. 1) within the last year. The detection of TCE in the Loma Linda system may be a result of the Texas Street (Redlands), Liquid Phase Granular Activated Carbon (GAC) groundwater treatment system, which removes TCE from groundwater, being taken off-line due to perchlorate over-load in the system. The TCE could have moved past the GAC system when it was non-operational .
CDHS staff contacted public works department staff for the City of Loma Linda to discuss any potential health concerns expressed by their customers. CDHS staff were informed that the City of Loma Linda has not received any calls from their customers relating to health concerns . The public works department staff did report receiving a few calls (approximately six) seeking general information about perchlorate (e.g., Where did the perchlorate come from and how did it get into the water?) after an article was published in The Sun (Redlands newspaper) in June, 1997 .
Based on 1990 Census data and information obtained from the City of Loma Linda, the population is approximately 23,000 people . The ethnic makeup of the city is: < 1% Native American, 13.6% Hispanic, 6.4% African American, 21.4% Asian or Pacific Islander, and 64% Caucasian. The age distribution of the city is approximately: 9% under 5 years, 15% 5 to 17 years, 13% 18 to 24 years, 36% 25 to 44 years, 13% 45 to 64 years, 14% 65 and older. The gender makeup is estimated to be 48% male and 52% female.
Housing occupancy consists of the following; 46% owner occupied, 50% renter occupied, 4% vacant or occasional use. The housing units for the city are as follow: 45% 1 unit detached (single family home), 11% 1 unit attached (duplex, condominium), 36% > 2 units, attached (apartments), and 18% mobile home, trailer, or other.
For target populations to be exposed to environmental contamination, there must be a mechanism by which the contamination comes into direct contact with the target population . This is called an exposure pathway. A completed exposure pathway consists of five elements: a source of contamination, an environmental medium and transport mechanism, a point of exposure, a route of exposure, and a receptor population (Attachment: Table 3). For a population to be exposed to an environmental contaminant, a completed exposure pathway (all five elements) must be present. The following is an example of a completed exposure pathway: a contaminant from a hazardous waste site (source) leaches into groundwater (medium, transport mechanism), the groundwater is then pumped and piped to houses and businesses (point of exposure) where the occupants drink the water (route of exposure and receptor population).
Completed Exposure Pathway
CDHS has determined that a completed exposure pathway exists where there are low levels of perchlorate in the Loma Linda municipal drinking water. Table 3 in the Attachment of this document, lists the elements and the receptor populations for the completed exposure pathway to the Loma Linda drinking water system. The most important route of exposure is through ingestion of the water. Inhalation is not a pathway of concern because perchlorate is not volatile (does not become a gas). Inorganic ions, like perchlorate are non-lipophilic (i.e., chemicals with an aversion to fat-like surroundings, such as the skin). Uptake through the skin would be minimal. However, there are studies underway which may provide additional information on perchlorate's potential for dermal uptake.
The next step after recognizing a completed exposure pathway is to determine at what level and length of time the receptor population(s) have been, or are being exposed, and if the exposure presents a public health hazard. The following paragraphs will discuss how CDHS made these determinations.
It is not clear when the perchlorate contamination first reached the City of Loma Linda wells, because monitoring did not begin until 1997. As discussed earlier, the average level of perchlorate in finished drinking water has been estimated at 6 ppb to 8 ppb . The DDW staff estimated that perchlorate has been a contaminant in a near-by Victoria Farms system well (not in the Loma Linda system) since 1994 . The Victoria Farms well drew water from a shallower groundwater aquifer than the Loma Linda system wells, which suggests that the plume would have to migrate a greater distance requiring a longer amount of time for the perchlorate plume to impact the Loma Linda system. Also, the Loma Linda system wells are located near the southern edge (boundary) of the plume, which is delineated by perchlorate levels measuring 18 ppb (Attachment: Figure 1). Initial results (20 ppb) measured in the Loma Linda system during May 1997, are consistent with the 18 ppb plume boundary (Attachment: Table 1). Based on these facts provided by the DDW staff, it is not likely that perchlorate levels in the past (prior to 1997) were higher than what has been measured.
CDHS compared the perchlorate data to the USEPA's provisional reference dose (RfD) (0.0001 to 0.0005 milligrams per kilogram per day (mg/kg/day)) in order to determine whether a toxicological evaluation (dose estimates) was warranted. Since 1997, no water has been served above the provisional action level (18 ppb). Doses would not exceed USEPA's provisional RfD (0.0001 to 0.0005 mg/kg/day) . This means that noncancer (thyroid depression) health effects should not have occurred or be occurring to individuals who drink water from the Loma Linda system. Therefore, at this time there is no need to further evaluate exposures to perchlorate in the Loma Linda municipal water system.
Even though exposures to perchlorate in the Loma Linda municipal water system are below levels of health concern, the community served by the City of Loma Linda may want a better understanding about the toxicity of perchlorate. The following section is meant to provide a general discussion on what is known about the toxicology of perchlorate.
Perchlorate inhibits the excessive synthesis and secretion of thyroid hormones by competitively inhibiting the accumulation of iodide in the thyroid . Discontinued administration of potassium perchlorate to Graves' Disease patients resulted in a return to their hyperthyroid condition (above normal levels of thyroid hormone in circulation) . People who have been treated with perchlorate have reported gastrointestinal irritation, skin rash, and hematological effects including agranulocytosis (a decrease in the number of granulocytic leukocytes in the peripheral blood) and lymphadenopathy (lymph node enlargement) . The severe hematological effects seem to be more likely to occur when large doses of more than 1,000 milligrams per day (mg/day) (approximately 14 mg/kg/day for a 154 pound man) are used .
Potassium perchlorate was extensively used for treatment of Graves' Disease patients in the late 1950s and 1960s. After the reports of the severe hematological effects, potassium perchlorate was not used for many years . In the early 1980s, physicians in Europe began using it again for the treatment of Graves Disease, and reporting no serious side effects occurring as long as the dose was kept below 1,000 mg/day . In addition, potassium perchlorate has been used in treating thyrotoxicosis (hyperthyroidism) resulting as a side effect from other drug therapies [13-17].
There are only a few studies of short-term exposure in persons without Graves' Disease . The animal studies that have been conducted have also involved short-term exposures and the doses were too high to see a level where there was no effect on the thyroid. Both human and animal studies have primarily examined the effects of perchlorate on the thyroid. Interference with the production of thyroid hormones has resulted in a below normal level of thyroid hormone in circulation (hypothyroidism). The effects of perchlorate on organ systems other than the thyroid needs to be explored, especially effects on the blood system (described above) and developmental effects (described later).
In 1992 and 1995, USEPA staff reviewed the perchlorate toxicological studies and derived a provisional reference dose (RfD) of 0.0001 to 0.0005 mg/kg/day [6, 18]. A RfD is a dose to which a person could be exposed over a long period of time without having any appreciable risk of a non-cancer health effects occurring. According to the USEPA, a perchlorate dose of 0.14 mg/kg/day or smaller would not be expected to be associated with any adverse effect on the thyroid (this is called the NOAEL or No Observable Adverse Effect Level) [18, 19]. The USEPA then applied an uncertainty factor of 300 or 1000 to the NOAEL to derive the RfD . Uncertainty factors are used to account for various uncertainties when there are gaps in scientific knowledge.
There is very limited information about whether perchlorate causes cancer. The only information about the possible carcinogenicity of perchlorate has to do with cancers of the follicular thyroid cells . Several animal studies found that thyroid tumors were induced in both rats and mice by long-term administration of high doses of perchlorate. However, the thyroid of rats are thought to be more sensitive to the effects of perchlorate than the human thyroid [20, 21]. Since perchlorate's possible carcinogenic effects on the thyroid are based on the same mechanism that determines its noncarcinogenic effects, it may be appropriate to consider the RfD as a dose which does not pose a significant risk of thyroid cancer .
It is even harder to determine whether or not perchlorate exposure can cause any other type of cancer. More toxicological information is needed to determine whether perchlorate can cause cancer and if it can, at what dose this effect may start occurring.
Children are not adults, their bodies are not fully developed, and they may not respond to perchlorate in the same manner as an adult. For instance, thyroid hormone is critical to normal brain development and physical development. The critical period of dependency on thyroid hormone begins in the uterus and extends up until three years of age. After the age of 3, thyroid hormone continues to play a primary role in physical development until puberty. Thus, a low level or absence of thyroid hormone in utero or in childhood could result in irreversible mental retardation and retarded physical growth.
Perchlorate can cross the placenta and thus could effect the developing fetus, though these effects have not been studied in humans. It is known, however, that drugs currently being used to treat Graves' Disease such as propylthiouracil do cross the placenta and can produce neonatal hypothyroidism and fetal in utero goiter (enlargement of the thyroid) [21, 23, 24-26]. In fact, because the developing fetus's thyroid is immature, because propylthiouracil is a more potent suppressor of thyroid function in the fetus than in the mother .
In a study of the effects of potassium perchlorate (740 mg/kg/day for the mother) fed to pregnant guinea pigs during pregnancy, a 15-fold enlargement of thyroid of the newborns was noted, even though no increase in the size of the mother's thyroids occurred . Thyroid hormone levels of the newborn guinea pigs were not measured in this study. Another animal study in which the mother was given fairly high levels of potassium perchlorate, also resulted in increased thyroid weight in the offspring of the mother . At this time, it is unclear whether lower doses of perchlorate would effect the thyroid of the developing fetus and young child and thus affect thyroid function at a time when normal thyroid hormone production is important to brain development.
Animal studies are underway which are exploring the toxicity of perchlorate, including effects on the immune system and developmental effects (see Recommendations section, page 10).
Until there is more information about perchlorate's effect on children, CDHS is not able to evaluate past exposures that occurred to child residents who received water from the Loma Linda system. To compare a child's exposure with toxicological information based on adult exposure ignores the fact that the child is not an adult.
Health Outcome Data:
Existing health databases such as cancer and birth defects registries and infant thyroid databases are generally useful if substantial exposures are documented or suspected for the neighborhoods in the vicinity of the site. A review of disease statistics would not be useful for determining potential health impact from exposure to perchlorate in the Loma Linda system because perchlorate distributed in the municipal drinking water were below levels likely to cause health effects. Even though the levels of perchlorate would not support a review of infant thyroid data for areas served by the Loma Linda system, it is possible that a California wide review of infant thyroid data may occur in the future.