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Contaminated Water Supplies at Camp Lejeune: Assessing Potential Health Effects
6
Epidemiologic Studies of Solvent-Contaminated Water Supplies
The results of studies of human populations that were exposed to solvents through water supplies were included as part of the comprehensive evaluations of the epidemiologic literature provided in Chapter 5. In those evaluations, the epidemiologic literature was considered comprehensively to evaluate a global question: What is the evidence that a particular chemical may be associated with a specific health outcome? The studies were dominated by occupational studies of dry cleaners and other workers, which typically have greater exposures that are well documented but are restricted to populations of relatively healthy men and involve exposure pathways that differ from those at Camp Lejeune.
This chapter focuses more on studies that addressed situations that approximate the circumstances at Camp Lejeune more closely (see Table 6-1). Those situations involve episodes of solvent contamination of water used by a community’s population for drinking, bathing, and other purposes. As at Camp Lejeune, a population’s water supply was contaminated with solvents from industrial sources, distributed to the public, and used for household purposes. Thus, such studies have had to grapple with the same methodologic challenges that face investigators of the Camp Lejeune situation, including exposure assessment, population identification, potential confounding factors, and small study size and statistical power. The exposed populations typically include the full spectrum of people—all ages, both sexes, and varied health status (including pregnancy)—with varied behavior related to water use and widely varying background influences on disease risk.
An examination of those studies in more detail contributes to the context and strategy for addressing environmental health concerns at Camp Lejeune. First, there may be methodologic lessons to be learned, such as beneficial research strategies that would be suitable for application to epidemiologic studies of Camp Lejeune. Second, as noted above, the studies share some important characteristics with the Camp Lejeune situation. Thus, in setting priorities for outcomes warranting attention at Camp Lejeune, the committee considered the studies of contaminated community water supplies as a distinctively relevant group of epidemiologic studies. Unfortunately, as noted below, methodologic limitations limited the contribution of such studies despite their advantages in being somewhat analogous to the Camp Lejeune water-contamination situation.
METHODS
Study Designs
The contamination events whose study is in Table 6-1 came to attention in a variety of ways. In one instance, a disease cluster raised attention (Mallin 1990), but it appears that all the others came to notice because environmental contamination raised concern about potential health effects among exposed
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Contaminated Water Supplies at Camp Lejeune: Assessing Potential Health Effects
TABLE 6-1 Summary of Epidemiologic Studies Involving Drinking-Water Contamination with TCE, PCE, and Other Solvents
Exposure Source
Study Design
Primary Exposure Assessment
Health Outcomes Evaluated
Relative Risk (95% CI); n = exposed cases
Potential Confounders Considered
Reference and Comments
Tucson, AZ (well contamination, 1969-1981)
TCE, dichloroethylene and chromium in groundwater from dumping of military, industrial wastes
Case-control
Parental residence or employment in census tracts likely to receive contaminated water at least 1 month before and during first trimester of pregnancya
Congenital heart defects
1969-1987: relative OR estimated to be 3 times greater in exposed group; n = 246
Goldberg et al. 1990, Bove et al. 2002; used inappropriate controls; imprecise geographic delineation of contaminated area
1969-1981: Bove et al. (2002) reanalyzed data to restrict analysis to contamination period; prevalence ratio, 2.6 (2.0-3.4)
Ecologic
Maternal address at delivery linked by GIS to census tracts served by contaminated wells, identified with groundwater transport and fate model
Low birth weight, very low birth weight, term low birth weight
1979-1981 (years with computerized records): very low birth weight (n = 13): adj OR, 3.3 (0.5-20.6)
Gestational time, prenatal-care index, pregnancy complications, pregnancy illness, congenital abnormalities, sex of baby, race of baby, Hispanic origin of baby, parity, age of mother, mother’s education, marital status
Rodenbeck et al. 2000
San Bernardino County, CA (well contamination, 1980-1990; study period, 1988-1998)
TCE, ammonium perchlorate in groundwater (unspecified source)
Ecologic
Residential location (13 census tracts served by contaminated wells)a
16 cancer types
Significantly higher number of cases than expected for uterine cancer (n = 124): RR, 1.4 (99% CI, 1.1-1.7); melanoma (n = 137): RR, 1.4 (99% CI, 1.1-1.8)
Morgan and Cassady 2002; authors attribute excess uterine cancer, melanoma to higher SES of exposed populationb
Santa Clara, CA (well contamination, 1980-1981; study period, 1980-1985)
Trichloroethane in groundwater contaminated by underground waste-solvent storage tank at semiconductor plant
Cohort
Maternal residence in census tract served by contaminated wella
Spontaneous abortion, congenital abnormalities, low birth weight
Spontaneous abortion (n = 64): adj RR, 2.3 (1.3-4.2); congenital malformations (n = 10): RR, 3.1 (1.1-10.4); no low-birth-weight babies born in contaminated area
Maternal age, alcohol consumption, smoking, prior fetal loss, number previous pregnancies, ethnicity, maternal exposure to organic solvents, petrochemicals, pesticides, x rays
Deane et al. 1989
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Contaminated Water Supplies at Camp Lejeune: Assessing Potential Health Effects
Cohort
Residential proximity to contaminated well, defined by census tracts, perioda
Spontaneous abortion, congenital abnormalities, low birth weight
Original study area: spontaneous abortion (n = 89): RR, 3.5 (1.2-10.3); congenital malformations (n = 96): RR, 4.3 (1.2-14.7); low birth weight (n = 281): RR, 0.7 (0.2-1.8)
Wrensch et al. 1990
For 1981, groundwater fate and transport model coupled to water-distribution model to estimate maternal first-month, first-trimester exposures
Adjacent census tract likely to have been exposed to water from contaminated wells: spontaneous abortion (n = 86): RR, 0.3 (0,1-1.1); congenital malformations (n = 105): RR, 0.9 (0,1-6.6); low birth weight (n = 294): RR, 1.7 (0.5-6.0)
Case-control
Consumption of tap, bottled water during first trimester (mostly tap water vs mostly bottled water); among women consuming mostly tap water, source (groundwater vs surface water) by county
Adverse pregnancy outcomes
Telephone respondents: spontaneous abortion: OR, 2.2 (1.4, 3.6); anomalies: OR, 1.8 (95% CI: 0.8, 4.1)
Hertz-Picciotto et al. 1992; (unadjusted) ORs are for consumption of tap, bottled water; hazard ratios also reported for spontaneous abortion by county (San Mateo, Alameda, Santa Clara), source of water (ground vs surface) in women consuming mostly tap water
Mail respondents: spontaneous abortion: OR, 1.3 (0.8, 2.0); anomalies: OR, 0.8 (0.4, 1.7)
Case-control
Maternal address at delivery linked to areas in (exposed), outside (unexposed) distribution systema
Congenital cardiac abnormalities
1981-1982: RR, 2.2 (1.2-4.0), n = 12
Swan et al. 1989
1981-1983: adj RR, 1.5 (0.8-3.0), n = 143
Mother’s education, race
Shaw et al. 1990
Denver, CO
TCE, PCE contamination of municipal wells from hazardous-waste sites
Cohort
Hydraulic simulation model, GIS used to assign mean TCE levels based on residential (census block) location
Neurobehavioral effects
Higher exposure (>15 µg/L; n = 20) associated with poorer performance on digit-symbol test (P = 0.07), contrast-sensitivity tests C, D (P = 0.06, 0.07); 37-83% higher mean scores for confusion, depression, tension; strong interaction with alcohol consumption
Self-reported consumption of seafood once a week or more, years of education, smoking, alcohol consumption
Reif et al. 2003
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Exposure Source
Study Design
Primary Exposure Assessment
Health Outcomes Evaluated
Relative Risk (95% CI); n = exposed cases
Potential Confounders Considered
Reference and Comments
Denver, CO
TCE, PCE contamination of municipal wells from hazardous-waste sites
Cohort
Hydraulic simulation model, GIS used to assign mean TCE levels based on residential (census block) location
Neurobehavioral effects
Higher exposure (>15 µg/L; n = 20) associated with poorer performance on digit-symbol test (P = 0.07), contrast-sensitivity tests C, D (P = 0.06, 0.07); 37-83% higher mean scores for confusion, depression, tension; strong interaction with alcohol consumption
Self-reported consumption of seafood once a week or more, years of education, smoking, alcohol consumption
Reif et al. 2003
Northwestern Illinois
Groundwater contamination (organic chemicals, heavy metals) due to dumping of solid, liquid wastes
Ecologic
Residence by county, ZIP code in nine-county areaa
Bladder cancer
RR in males (n = 21), 1.7 (1.1-2.6); females (n = 10), 2.6 (1.2-4.7)
Mallin 1990
Woburn, MA, 1964-1983
TCE, PCE in municipal wells contaminated by industrial wastes
Cohort
Annual estimates of fraction of water supply served by contaminated wells; residential historya
Childhood leukemia, adverse pregnancy outcomes, childhood disorders
Positive associations reported for childhood leukemia (n = 20; P = 0.001), eye or ear anomalies (n = 9; P < 0.0001), CNS or chromosomal or oral cleft anomalies (n = 8; P = 0.01), kidney or urinary tract disorders (n = 43; P = 0.02), lung or respiratory disorders (n = 192; P = 0.05), perinatal deaths, 1970-1982 (n = 4; P = 0.003) RR, 8.3 (0.7-94.7); n = 19; dose-response trend (P < 0.05)
Smoking, age, prior fetal loss, prior perinatal death, prior low birth weight, prior musculoskeletal anomaly, SES, year pregnancy ended
Lagakos et al. 1986
Case-control
Average, cumulative exposure metricsa
Childhood leukemia
RR, 8.3 (0.7-94.7); n = 19; dose-response trend (P < 0.05)
Costas et al. 2002
Cape Cod, MA
Leaching of PCE from inner vinyl lining of asbestos cement water-distribution pipes
Case-control
Residential history, water flow, pipe characteristics to predict PCE in distribution systema
Leukemia and lung, breast, colorectal, bladder, kidney, pancreatic, brain, liver cancer
Cancers with increased risk: leukemia (no latency): adj OR, 2.1 (0.9-5.2); n = 34
Sex, age at diagnosis or index year, vital status, education level, occupational exposure to solvents, prior medical treatment with irradiation
Aschengrau et al. 1993
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Case-control
See Aschengrau et al. (1993)
Breast cancer
Adj OR (for latency of 0-15 years), 1.6 (1.1-2.4) to 1.9 (1.1-3.2); n = 930
Age at diagnosis or index year, vital status, family history of breast cancer, age at first live birth or stillbirth, prior breast cancer or benign breast disease, occupational
Aschengrau et al. 1998, 2003 (combined data presented)c
Case-control
Annual PCE levels (see Aschengrau et al. [1993]) coupled to information on tap water consumption and bathing habits
Breast cancer
Adj OR for latency of 0-15 years), 1.4 (0.8-2.5) to 1.9 (0.6-5.9); n = 154d
Age at diagnosis or index year, family history of breast cancer, prior breast cancer, age at first live birth or stillbirth, occupational exposure to PCE
Vieira et al. 2005
Case-control
See Aschengrau et al. (1993)
Colorectal, lung, brain, pancreatic cancer
Cancers with increased risk: colorectal cancer (11-year latency): adj OR, 1.7 (0.8-3.8); n = 311
Age at diagnosis or index year, vital status, sex, occupational exposure to solvents, history of polyps, inflammatory bowel disease, or ulcerative colitis, occupational history associated with colorectal cancer (exposure to asbestos, solvents)
Paulu et al. 1999
Cohort
Residential history; leaching, transport model; water-distribution model, GIS to predict monthly levels at nodes in distribution system
Birth weight, gestation duration
No associations found between exposure and birth weight or gestational duration; n = 1,353
Gestational age, maternal race, education level, history of low-birth-weight child, occupational exposure to solvents, use of self-service dry cleaning, residential proximity to dry-cleaning establishments, prior preterm delivery, obstetrical complications in current pregnancy
Aschengrau et al. 2008
Upper New Jersey (Bergen, Essex, Morris, Passaic Counties)
TCE, PCE
Ecologic
Residential locationa
Leukemia
Leukemia, males: SIR, 1.0 (0.7-1.5), n = 25; females: SIR, = 1.5 (1.0-2.2),
Fagliano et al. 1990
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Exposure Source
Study Design
Primary Exposure Assessment
Health Outcomes Evaluated
Relative Risk (95% CI); n = exposed cases
Potential Confounders Considered
Reference and Comments
TCE, PCE
Ecologic
Average 1984-85 levels from quarterly monitoring data for 75 towns
Leukemia, NHL
For highest exposure stratum: leukemia in males: RR, 1.1 (0.8-1.4), n = 63; females: RR, 1.4 (1.1-1.9), n = 56; acute lymphocytic leukemia in females <20 years old: RR, 3.3 (1.3-8.2), n = 6; NHL in males: RR, 1.2 (0.9-1.5), n = 78; females: RR, 1.4 (1.1-1.7), n = 87; diffuse large-cell NHL in males: 1.6 (1.0-2.4), n = 26; females: RR, 1.7 (1.1-2.6), n = 24; non-Burkitt’s in males: RR, 1.9 (0.5-6.8), n = 3; females: RR, 3.2 (1.2-8.2), n = 6
Cohn et al. 1994
TCE, PCE from landfill leachate, industrial waste disposal, leaking underground storage tanks
Case-control
Maternal address at delivery; monthly estimates from quarterly monitoring data from 75 municipalitiesa
SGA, preterm birth, birth weight, birth defects, fetal death
TCE: CNS defects: OR, 1.7 (90% CI, 0.8-3.5), n = 6; neural-tube defects: OR, 2.5 (90% CI, 0.9-6.4), n = 4; oral-cleft defects: OR, 2.2 (90% CI, 1.2-4.2), n = 9
Maternal age, race, education level, primipara, prior fetal loss or stillbirth, sex of child, adequacy of prenatal care
Bove et al. 1995; if adjuste d OR differed by more than 15%, adjusted value was reported as OR; no distinction made between adjusted and unadjusted values
PCE: oral-cleft defects: OR, 3.5 (90% CI, 1.3-8.8), n = 4
Southern Finland
TCE, PCE from industrial sources, dump site
Ecologic
Residence at diagnosis (Hausjarvi and Hattula)a
Liver cancer, NHL, Hodgkin disease, multiple myeloma, leukemia
Increaseded risks in Hausjarvi: leukemia: RR, 1.2 (0.8-1.7), n = 33; Hattula: NHL: RR, 1.4 (1.0-2.0), n = 31; Hodgkin disease: RR, 1.4 (0.7-2.5), n = 11
Vartiainen et al. 1993
Taoyuan County, Taiwan
Hazardous-waste site (formerly electronics factory)
Case-control
Residential proximity to contaminated wells, period of deatha
Cancers
Leading causes of cancer deaths in all male population: liver: adj MOR, 2.6 (1.2-5.5), n = 53; stomach: adj MOR, 2.2 (1.0-4.9), n = 39; lung: adj MOR, 1.8 (0.8-3.9), n = 41; colorectal: adj MOR, 0.8 (0.2-2.9), n = 26; all: adj, MOR, 2.1 (1.3-3.3), n = 266
Lee et al. 2003
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Indiana, Illinois, Michigan
Superfund sites
Cohort
Listed in TCE exposure registrya
Multiple health outcomes
Statistically significant results for stroke: adj OR, 3.2 (1.1-9.0) to 4.1 (1.5-11) for max. TCE quartiles, n = 60; respiratory allergies: adj OR, 2.2 (1.1-4.2), n = NR; asthma, emphysema: adj OR, 1.8 (1.0-3.3) for cumulative exposure, n = NR
Age, sex, smoking, occupational exposure, education level for stroke; age, sex for asthma, emphysema
Burg and Gist 1999
Michigan, Indiana, Pennsylvania, Arizona
Superfund sites
Cohort
Listed in TCE exposure registrya
Multiple health outcomes
Excess cases over lifetime of registry for anemia, other blood disorders, liver problems, rashes, eczema, other skin allergies
Davis et al. 2005
Iowa
Water-disinfection byproducts
Ecologic
Water-supply source
Bladder, breast, colon, lung, prostatic, rectal cancer
No associations between TCE or PCE and cancers
Isacson et al. 1985
a See Table 6-2 for more detailed exposure data.
b Higher than average SES predicts access to health care, which enhances detection of melanoma. Access to health care also makes it more likely that postmenopausal women will receive estrogen-replacement therapy, which is linked to increased endometrial cancer (main form of uterine cancer).
c Adjusted OR in Aschengrau et al. (1998) ranged from 0.6 (0.0-3.7) to 2.3 (0.6-8.8), n = 258; adjusted OR in Aschengrau et al. (2003) ranged from 1.5 (1.0-2.4) to 1.9 (1.0-3.5) for 0-15 years of latency, n = 672.
d Analysis restricted to nonproxy subjects.
Abbreviations: CI = confidence interval, CNS = central nervous system, GIS = geographic information system, MOR = mortality odds ratio, NHL = non-Hodgkin lymphoma, NR = not reported, OR = odds ratio, PCE = perchloroethylene, RR = relative risk, SES = socioeconomic status, SGA = small for gestational age, SIR = standardized incidence ratio, SRR = standardized rate ratio, TCE = trichloroethylene.
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Contaminated Water Supplies at Camp Lejeune: Assessing Potential Health Effects
residents. All the studies included a broad enough geographic area or period to contrast disease risks in people with greater and smaller degrees of exposure associated with the contamination, and the quality of the exposure assessment varied widely among the studies. A time element was also used to define exposure, such as residence in a specific location over a specific calendar period. In some instances, people were asked detailed questions to help to characterize exposure beyond the geography and the period of contamination related to water use. Because exposure was driven largely by residential location, the studies are susceptible to confounding by the many geographically based attributes that affect disease other than the exposure of interest, such as socioeconomic differences or associated lifestyle factors, for example, tobacco or alcohol use and quality of medical care that might affect diagnoses. Some studies (Hertz-Picciotto et al. 1992; Aschengrau et al. 1993, 1998; Costas et al. 2002; Reif et al. 2003) included individual interviews, which made it possible to assess and consider a variety of potential confounders in the analysis.
Exposure Assessment
Table 6-2 presents exposure data from the studies in Table 6-1 that monitored concentrations of trichloroethylene (TCE), perchloroethylene (PCE), and other solvents in production wells from which water was pumped for delivery to the distribution systems of the affected communities. The way in which the episodes studied were identified (the discovery of contaminated water supplies at some time) means that monitoring data on a water supply for the putative agents were largely nonexistent except for periods close to or right after identification of the problem, as was the case at Camp Lejeune. In Woburn, Massachusetts, for example, concerns about possible contamination from industrial wastes in the late 1970s led to the testing and closing of wells in which increased concentrations of TCE (267 ppb) and PCE (21 ppb) were detected (Lagakos et al. 1986). The Santa Clara County contamination incident in California is another example of a well’s being shut down immediately after the detection of high concentrations of trichloroethane (1,700 ppb) (Deane et al. 1989). Another well-known contamination episode occurred in Cape Cod, Massachusetts, as a result of leaching of PCE from the vinyl lining of asbestos-cement water-distribution pipes. The lining of the pipes had been applied in the late 1960s, but the contamination was discovered only after sampling was carried out more than 10 years later. In that instance, the range of the measurements collected throughout the distribution system constituted evidence of spatial variability in contaminant concentrations: concentrations at low-use locations (1,600-7,750 μg/L) were 20-5,000 times higher than those at high-use locations (1.5-80 μg/L).
To compensate for the lack of monitoring data in studies of increased health risks associated with contaminated drinking water, investigators used exposure assessments whose complexity depended on the sources of data and the metrics. One of the simplest surrogates of exposure relied on residential proximity to the source of contamination. In those cases, exposure was inferred from residence in areas served by contaminated wells (Deane et al. 1989; Swan et al. 1989; Goldberg et al. 1990; Wrensch et al. 1990; Lee et al. 2003); in one study, the inference was aided by groundwater transport and fate models to define potentially exposed areas (Rodenbeck et al. 2000) and in another by groundwater sampling (albeit later than the study period) to verify the classification of exposed areas downstream of the source (hazardous-waste site) of the contamination (Lee et al. 2003). In the only study that relied on biologic monitoring to evaluate potential solvent exposure, Vartiainen et al. (1993) compared urinary metabolites of TCE and PCE (dichloroacetic acid and trichloroacetic acid) in residents of municipalities with and without groundwater contamination.
More sophisticated exposure-assessment approaches have used hydraulic modeling of the water-distribution system that accounts for the pumping of water from both contaminated and uncontaminated wells and for characteristics of the pipe network (such as geometry, age, diameter, and leaks). For example, several studies of the potentially affected community in Woburn, Massachusetts, used a hydraulic mixing model to estimate the fraction of water received by each residence weekly (Lagakos et al. 1986) or monthly (MDPH/CDC/MHRI 1996; Costas et al. 2002) from contaminated wells. Wrensch et al. (1990)
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TABLE 6-2 Summary of Reported Water-Monitoring Data in Published Epidemiologic Studiesa
Source of Contamination
Sampling Period
Sampling Location
Contaminant
Concentrations
Reference and Comment
Tucson Valley, AZ
Industrial wastes
1981
9 public wells
TCE
6-239 ppb
Goldberg et al. 1990
Santa Clara County, CA
Unspecified
1980 and later 2001
20 public wells
TCE
0.09-97 ppb (<5 ppb in distribution system since 1991)
Morgan and Cassady 2002
Public wells (number not specified)
Ammonium perchlorate
5-98 ppb (<18 ppb since 2001)
Santa Clara County, CA
Underground waste-solvent storage tank (near semiconductor plant)
Dec. 7, 1981
Public well 13
1,1,1-TCA
1,700 ppb
Deane et al. 1989; Swan et al. 1989; Wrensch et al. 1990; well 13 removed from service on Dec. 7, 1981
Dec. 14, 1981
1,1,1-TCA
8,800 ppb
Mar. 1982
1,1,1-DCE
8.8 ppb
Mar. 1982
Public well 8
TCA
33.5 ppb
DCE
9.6 ppb
Northwestern Illinois
Dumping of solid, liquid wastes
1982-1988
Public well 1
Benzene
<1 ppb
Mallin 1990
1,2-Dichloroethane
1.6-2.1 ppb
1,1,1-TCA
7 ppb
1,1-Dichloroethane
2-11 ppb
trans-1,2-DCE
8-42 ppb
Methylene chloride
<1 ppb
PCE
<1ppb
TCE
2-10 ppb
Chloroform
1.3 ppb
Dibromochloromethane
<1 ppb
Public well 2
Benzene
1.3-2 ppb
1,2-Dichloroethane
1.7-2 ppb
1,1,1-TCA
1 ppb
1,1-Dichloroethane
1-4.6 ppb
trans-1,2-DCE
14-38 ppb
Methylene chloride
1-5 ppb
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Contaminated Water Supplies at Camp Lejeune: Assessing Potential Health Effects
Source of Contamination
Sampling Period
Sampling Location
Contaminant
Concentrations
Reference and Comment
PCE
5.1 ppb
TCE
2-15 ppb
Chloroform
27 ppb
Dibromochloromethane
12 ppb
Woburn, MA
Industrial wastes
1979
Public wellsG and H
TCE
267 ppb
Lagakos et al. 1986; Costas et al. 2002; Byers et al. 1988; wells closed after sampling in May 1979
PCE
21 ppb
Trichlorofluoroethane
23 ppb
DCE
28 ppb
Arsenic
0.0020 ppm
Chloroform
11.8 ppb
Cape Cod, MA
TCE in inner vinyl lining of asbestos-cement water-distribution pipes
~1980
Water-distribution pipes
PCE
1,600-7,750 μg/L
Aschengrau et al. 1993, 1998, 2003, 2008; Paulu et al. 1999; Massachusetts Department of Environmental Protection began program of flushing, continuous bleeding in 1980 to lower PCE concentrations
Low-use sites
1.5-80 μg/L
Medium-and high-use sites
High value of 18,000 μg/L at dead-end sites in Falmouth reported in Paulu et al. (1999)
Rhode Island
1976
Water-distribution s stems
PCE
800-2,000 μg/L
Paulu et al. 1999
Upper New Jersey (Bergen, Essex, Morris, Passaic Counties)
Landfill leachate; industrial waste disposal, leaking underground storage tanks
1985-1988
49 distribution systems serving 75 towns
Monthly estimates:
Bove et al. 1995
TCE
55 ppb
PCE
26 ppb
1,1,1-TCA
18 ppb
Carbon tetrachloride
7 ppb
1,2-Dichloroethane
19 ppb
Total DCE
16 ppb
Benzene
2 ppb
Total trihalomethanes
299 ppb
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Contaminated Water Supplies at Camp Lejeune: Assessing Potential Health Effects
1984-1985
Routine sampling in distribution systems of 27 towns in Lower Passaic River and Saddle River drainage basin
14 unspecified compounds
Sum of average of nontrihalomethane VOCs (no. towns)
Fagliano et al. (1990)
72 μg/L (1)
67 μg/L (1)
47 μg/L (1)
40 μg/L (1)
37 μg/L (1)
12 μg/L (1)
9 μg/L (1)
7 μg/L (1)
5 μg/L (4)
3 μg/L (2)
2 μg/L (2)
1 μg/L (9)
0 μg/L (2)
Southern Finland
Industrial sources (Oitti)
1992
Drinking-water samples
TCE, PCE (Oitti)
100-200 μg/L
Vartiainen et al. 1993
Dump site (Hattula)
July 1992
TCE (Hattula)
212 μg/L
66 μg/L
Taoyuan County, Taiwan
Hazardous-waste site (formerly electronics factory)
Oct. 1999-May 2000
Residential wells
Median (range)
Lee et al. 2003; previous reports of off-site groundwater contamination indicated up to 930 and 4,800 μg/L for TCE and PCE, respectively
Vinyl chloride
0.003 μg/L (ND-72.3)
Tetrachloroethene
2.95 μg/L (ND-5,228.3)
TCE
28.43 μg/L (ND-1,790.7)
1,1-DCE
1.35 μg/L (ND-1,240.4)
1,1,1-TCA
0.67 μg/L (ND-1,504.4)
cis-1,2-DCE
3.05 μg/L (ND-1,376.0)
1,1-Dichloroethane
1.81 μg/L (ND-227.9)
Indiana, Illinois, Mich
National Priorities List sites
TCE subregistry site
TCE
Maximum/median (no. household samples)
Burg and Gist 1999
Verona Well Field and Dowaglac (MI)
2,000/6.0 ppb (66)
McGraw-Edison Corporation (MI)
733/1.0 ppb
Superior Street (IN)
19,380/84.0 ppb (134)
Central Area (IN)
114/0.4 ppb (28)
Gemeinhardt Piccolo Company (IN)
1,600/4.0 ppb (100)
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Contaminated Water Supplies at Camp Lejeune: Assessing Potential Health Effects
Source of Contamination
Sampling Period
Sampling Location
Contaminant
Concentrations
Reference and Comment
Conrail Rail Yard (IN)
1,520/78.0 ppb (49)
Acme Solvents Reclamation, Inc. (IL)
100/1 ppb (13)
Beloit Corporation (IL)
3/2 ppb (3)
Byron Johnson Salvage Yard (IL)
249/9.1 ppb (25)
Frinks Industrial Waste (IL)
16/14.0 ppb (5)
Southeast Rockford groundwater contamination (IL)
122/15.0 ppb (331)
Warner Electronic Brake and Clutch Company (IL)
5,220/234.0 ppb (74)
Michigan, Indiana, Illinois, Pennsylvania, Arizona
National Priorities List sites (n = 15)
Residential sites
TCE
Median concentrations, 0.4-234 ppb; maximum concentrations, 3-24,000 ppb
Davis et al. 2005
Iowa
Sampling of drinking water from treatment plants at municipalities in Iowa serving 1,000 or more residents
TCE
Data reported as % of towns with detectable VOC concentrations by source of supply water (surface, <46 m, 46-152 m, >152 m)
Isacson et al. 1985
PCE
1,2-Dichloroethane
1,1,1-TCA
aFollowing studies were also evaluated for water-monitoring data, but none were found: Cohn et al. (1994); Hertz-Picciotto et al. (1992); Reif et al. (2003); Rodenbeck et al. (2000); Shaw et al. (1990); Viera et al. (2005).
Abbreviations: DCE = dichloroethylene, ND = not detected, PCE = perchloroethylene, TCA = trichloroacetic acid, TCE = trichloroethylene, VOC = volatile organic compound.
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developed a groundwater fate and transport model to estimate concentrations of trichloroethane in the aquifer that supplied water to the production well (in which the contamination was detected); the results were coupled to a water-distribution model to estimate the probability that water from the contaminated well reached specific locations in the distribution system. In studies carried out to investigate the cancer risk posed by PCE-contaminated drinking water in Cape Cod, Massachusetts, investigators used a water-distribution model (the Webler-Brown model) that predicted the amount of PCE leaching from the vinyl-lined pipes and then transported to residences served by the distribution systems (Aschengrau et al. 1993, 1998; Paulu et al. 1999); the modeling effort was later improved on by using geographic information systems (GISs) (rather than tax-assessor maps) to geocode key elements of the water-distribution system and study participants’ residences (Aschengrau et al. 2003). Reif et al. (2003) also took advantage of the capabilities of GISs and linked residences of persons living near the Rocky Mountain Arsenal whose water supply had been contaminated with TCE to results from a hydraulic model (EPANET) to reconstruct 1985 contaminant concentrations at specific nodes in the distribution system.
Cognizant that exposure is influenced not only by concentrations of a contaminant in drinking water but by the amount of water consumed or used in other ways, investigators have also gathered individual-level information about consumption patterns, bathing and showering habits, and other water-related behavior with questionnaires or interviews. The resulting data have been used to form the primary exposure measure for evaluating the associations between contaminated drinking water and adverse health outcomes (for example, consumption of cold tap water by source and year) (Shaw et al. 1990) and have been incorporated as covariates in the multiple logistic regression models that have been applied. For example, in addition to evaluating the effect of living in an area served by a contaminated well in Santa Clara, California, consumption of cold tap water at home (Deane et al. 1989; Wrensch et al. 1990) and water-filter use (Wrensch et al. 1990) were assessed. To evaluate heterogeneity in the effects of contaminated water on cancer risk due to water-related behavior, stratified analyses by usual bathing habits (mostly showers, mostly baths, or about equal baths and showers) were conducted in the studies carried out in the Upper Cape region of Massachusetts (Ashengrau et al. 1993, 1998; Paulu et al. 1999). It would be of interest to examine results of studies that used more and less sophisticated approaches to assess exposure, but the contamination episodes are so different from one another that it is impossible to isolate the quality of exposure assessment as an independent influence on the final results.
Health-Outcome Assessment
With few exceptions (such as the study of neurobehavioral function in a Colorado population exposed to solvents [Reif et al. 2003] and the study of pregnancy outcome in Santa Clara, California [Hertz-Picciotto et al. 1992]), all the studies have assessed health outcomes on the basis of existing records. Much of the attention in those studies has been on birth outcomes, including the information obtainable through birth records, which constitute one of the few universal health registry systems available in the United States and eliminate concerns about nonresponse. For all geographic areas and for all periods going back several decades, birth weight, duration of gestation, and selected social and demographic factors can be ascertained. Thus, a number of studies addressed birth weight, preterm birth, and stillbirth.
Some areas have population-based registries of congenital defects and cancer that provide comprehensive coverage of geographically defined populations and periods and allow evaluation of associations with exposures also defined by geography and time. Studies of cancer in Massachusetts, Illinois, and New Jersey have relied on outcome ascertainment from population-based registries (Fagliano et al. 1990; Burg and Gist 1999; Aschengrau et al. 2003). The advantage of using established birth or disease registries is efficiency in time and expense of the studies, but they are limited by the quality of the registries (with respect to comprehensiveness and accuracy of diagnoses) and constrain the scope of studies to the subset of health outcomes on which data are available. Pregnancy outcomes and cancer are often important concerns in episodes of solvent-contaminated water, but they are rarely the only concerns, and other outcomes remain unaddressed.
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The alternative approach, applied in Colorado (Reif et al. 2003) and California (Deane et al. 1989; Hertz-Picciotto et al. 1992) is to identify the population of concern on the basis of exposure (a product of location and time), sample that population to include the desired exposure contrasts, and conduct more detailed health assessments of individuals. Reif et al. (2003) selected residentially exposed persons and tested neurobehavioral characteristics, outcomes not otherwise assessable with existing registries. Similarly, miscarriage assessment requires collecting information directly from potentially affected people, as was done in Santa Clara, California. There is a marked increase in the expense, but the approach allows a focus on the health outcomes of greatest concern rather than those on which data are readily available. In contrast, the need to rely on respondent cooperation to identify people and include them in a study incurs a cost in the potential for bias due to nonparticipation, which is not a problem with registry-based studies. The quality of self-reported data may also be lower for some outcomes.
RESULTS
The studies of populations exposed to contaminated water supplies have generated a wide array of positive associations, as reflected in Table 6-1. Among the most increased relative risks were those for congenital heart defects (odds ratio [OR], 2.6; 95% confidence interval [CI], 2.0-3.4) in Tucson, Arizona (Bove et al. 2002); spontaneous abortion (OR, 2.3; 95% CI, 1.3-4.2) and congenital defects (OR, 3.1; 95% CI, 1.1-10.4) in Santa Clara, California (Deane et al. 1989); and liver cancer (OR, 2.6; 95% CI, 1.2-5.5) in Taoyuan County, Taiwan (Lee et al. 2003).
Although the evidence linking solvents in water supplies to individual outcomes seems impressive in specific studies, the lack of corroboration among studies (or even attempted corroboration in many instances) weakens their credibility. Furthermore, these largely opportunistic studies typically considered the full array of available outcomes from birth certificates, registries, and other available sources and reported the positive findings that emerged from such broad explorations. The universe of other outcomes considered in the studies is not always clear, and the broader universe of investigations of water-contamination episodes that did not identify “interesting” associations and were therefore never published is also unknown and could be substantial. In addition, the focus in many cases on rare outcomes (such as individual birth defects and childhood cancers) renders the resulting risk estimates highly imprecise and driven by as few as two or three cases. Although it is possible that some of the scattered, isolated findings are meaningful and could eventually be proved to indicate a replicable association with a specific health outcome, the results presented in Table 6-1 do not support such a conclusion. Therefore, even acknowledging that the studies are more directly comparable with the Camp Lejeune circumstances than the methodologically stronger studies discussed in Chapter 5, the committee concluded that the epidemiologic literature would be most effectively used if all of it, rather than only studies of community water-contamination episodes, were comprehensively evaluated. The studies reviewed in this chapter were given extra attention because of their applicability, and in some instances (such as the evidence linking water solvents to breast cancer on Cape Cod [Aschengrau et al. 1998, 2003]) the findings contributed substantially to identifying priorities. However, our interpretation of the epidemiologic studies in their totality was not dominated by them.
DISCUSSION
The studies discussed in this chapter yielded reports that were deemed by the investigators and scientific journals to be worthy of publication and that might have generated a disproportionate representation of positive findings. The findings of those studies should not be viewed as a representative or comprehensive set of findings, because investigation of contamination episodes is commonly undertaken by health departments but rarely reported in the literature. Relative to studies of occupational cohorts, which often have much higher and better documented exposures and large populations, the community studies
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are limited by the quality of exposure data and to various extents by the low size of their populations, particularly if such rare outcomes as childhood leukemia and congenital defects are being addressed. Even if the different routes of exposure—inhalation vs ingestion—are recognized, the occupational studies tend to dominate the evidence. The committee has incorporated the information from solvent water-contamination studies, as warranted, into the overall assessments of the epidemiologic evidence as reflected in the tables and categorization of evidence in Chapter 5 and focuses here on any special contributions as a function of the more direct relevance of water contamination as the source of exposure.
With regard to methods, the studies in this chapter have largely started with the conventional approach of characterizing a broad geographic area and period and relating health outcomes to estimated exposure. However, several have gone further in refining the exposure estimates by using sophisticated engineering models (particularly in Woburn, Massachusetts) in ways that are broadly applicable to the situation at Camp Lejeune. Similarly, the Cape Cod studies have gone beyond routinely available information on water source to estimate delivered dose.
The strategy pursued by Reif et al. (2003) and in the series of Santa Clara, California, studies (for example, Wrensch et al. 1990) also warrants consideration. They began with an episode of environmental contamination but proceeded to conduct individual data collection with interviews, medical records, and, in the case of the Denver, Colorado, episode, direct evaluation of potentially affected individuals. Available records have merit as a starting point, but for many health outcomes of interest it is essential to go further to collect new data.
CONCLUSIONS
Collectively, the epidemiologic studies of solvent contamination of water supplies and adverse health effects are of limited quality. If their distinctive strengths and limitations are taken into account, such studies contribute to the overall assessment of the epidemiologic literature, but the committee has judged that their strengths (comparability with Camp Lejeune in exposure pathways and diversity of exposed population) do not overcome their limitations (especially quality of exposure assessment, lower range of exposure, and imprecision in measures of association) to allow identification of high-priority outcomes on the basis of their results alone.