DEL MONTE CORPORATION
(OAHU PLANTATION)
KUNIA, HONOLULU COUNTY, HAWAII
In order to determine what environmental contaminants might be of concern, ATSDR has evaluated all of the available environmental monitoring data (1977 to present). Environmental data were taken from references 10, 11, 12, 13, 14, 15, 16, 17. Comparison values were used as a basis for evaluation of the data and to determine which contaminants should be looked at more closely. Comparison values are estimated health-based environmental concentrations below which no known or anticipated adverse effect on the health of persons should occur. The values allow adequate margins of safety. Appendix 2 contains descriptions of the comparison values used in this public health assessment.
A contaminant is selected for further evaluation if the contaminant concentration in a valid environmental sample exceeds comparison values. The presence of a contaminant on the lists in the tables of this section does not mean that either exposure to the contaminant or adverse health effects has occurred or will occur. Inclusion in the list indicates only that the potential for human exposures to the selected contaminants and the potential for adverse human health effects as a result of any exposures to the selected contaminants are discussed in more detail in later sections of this public health assessment.
From 1980 to 1981, 20 soil borings were conducted to determine the extent of subsurface (greater than 3 inches) soil contamination at the Drum Storage Area and the 1977 Spill Area (see Appendix 1, Figure 1). Table 1 contains the analytical results of soil samples taken from these bore holes are presented. The highest EDB subsurface soil contamination (118,100 micrograms of EDB per kilogram of soil [µg/Kg] or ppb) was found 30 to 32 feet below the surface at the Drum Storage Area. The highest DBCP subsurface soil contamination (2,964,000 µg/Kg) was also found at the Drum Storage Area 0 to 2 feet below the surface (10,11).
While the soil borings were being conducted, a previously unknown groundwater aquifer system was discovered (see Appendix 1 Figure 2 for a depiction of the local groundwater system). This upper aquifer is found at 20 to 30 feet below the surface and extends to about 150 feet below the surface. Because of the soil and rock composition at these depths, this upper aquifer does not yield very much water (less than 10 gallons per minute). Therefore, it is not used for any irrigation or potable water supplies. Groundwater samples (1981 to present) were taken from soil boring holes number 3, 6, and 9. Groundwater extraction wells were installed in 1981 (well numbers 3X, 6X, and 9X). Table 1 presents the analytical results of groundwater samples (labeled Upper Aquifer Groundwater in the table) taken from bore holes number 3, 6, and 9 or extraction wells number 3X, 6X, and 9X. The highest upper aquifer groundwater contamination (EDB and DBCP) was found 60 to 70 feet below the surface in bore hole number 9. Groundwater was not encountered or groundwater samples were not taken from the other bore holes; the information was not recorded (10,11).
The owners of the Del Monte Plantation did extract groundwater from the upper aquifer since 1981. Extraction well number 9X has been the only well which has consistently been able to withdraw water. EDB levels in extraction well number 9X have fallen from a high of 235,000 µg/L to about 19 µg/L. DBCP concentrations in extraction well number 9X has fallen from a high of about 44,640 µg/L to 0.74 µg/L (10-17).
The only on-site groundwater samples from the Waipahu Basal Aquifer (approximately 830 feet below the surface) were taken from the Kunia well (United States Geological Survey [USGS] number 2703-01). No monitoring wells have been installed in the Waipahu Basal Aquifer. The analytical results of the Kunia well samples (more than 400 analyses from 1977 to present) are summarized in Table 1 (labeled Waipahu Basal Aquifer). Analysis of water samples taken from the Kunia well indicates that the well water does not contain any metals (e.g., arsenic) above health comparison values. Since the owners of the Del Monte Plantation pumped and monitored the Kunia well, the concentrations of EDB have fallen from a high of 300 µg/L to 0.16 µg/L. DBCP concentrations have fallen from a high of 14 µg/L to 1.36 µg/L (10-17).
| Table 1 - Environmental Contaminants Detected Above Health Comparison Values at the Del Monte Oahu Plantation National Priorities List Site, Hawaii (10-17) | ||||||
| Contaminant | Range in Subsurface Soil (µg/Kg) | Comparison Value for Ingestion (µg/Kg)* | Range in the Upper Groundwater Aquifer (µg/L) | Range in the Kunia Well** - Waipahu Basal Aquifer (µg/L) | Comparison Value for Ingestion (µg/L)* | Comparison Value Source* |
| Ethylene Dibromide | <1.0-118,100 | 8.0 | <0.2-235,000 | <0.2-300 | 0.0004 | CREG |
| 1,2-Dibromo-3-Chloropropane | <1.0-2,964,000 | 4,000 (EMEG) |
<0.2-44,640 | <0.1-14.0 | 0.2 (MCL) |
EMEG and MCL |
| * - See Appendix 2 for a description of the comparison values and their sources.
** - United States Geological Survey number 2703-01. µg/Kg - micrograms of contaminant per kilogram of soil µg/L - micrograms of contaminant per liter of water | ||||||
None of the environmental samples taken to date at the Del Monte Oahu Plantation National Priorities List (NPL) site have been analyzed for any other contaminants besides EDB, DBCP, and metals (10-17).
The three upper aquifer extraction wells are the only upper aquifer monitoring wells. Therefore, it is not possible to determine whether the contaminants in the upper aquifer have migrated beyond the source areas (away from the Spill Area or the Drum Storage Area) or the plantation boundaries. Because pesticide storage and mixing activities occurred at the Drum Storage Area since the 1940s, it is possible that the upper aquifer EDB and DBCP contamination could have migrated beyond the Drum Storage Area.
No groundwater monitoring wells have been installed in the Waipahu Basal (deep) Aquifer. Therefore, it is not possible to determine the extent of site-related groundwater contamination in the Waipahu Basal Aquifer.
The two wells that provide drinking water to Kunia (i.e., the Navy Well Number 3 [USGS number 2803-05] and Field Well Number 4 [USGS number 2803-07]) have been tested for EDB, DBCP, and the substances on the Safe Drinking Water Act monitoring list. Analytical results of samples taken from the wells indicate that the water does not contain any contaminants above health comparison values. The analytical results did detect some trace concentrations of volatile organic compounds (i.e., trans-1,2-dichloroethene, cis-1,2-dichloroethene, carbon tetrachloride, trichloroethylene, and 1,2,3-trichloropropane) (10,17). However, the detected concentrations were below health comparison values. Table 2 summarizes the analytical results and comparison values of the samples taken from the two wells. In February, 1989, a packed tower aeration facility was installed. This tower reduces the concentration of volatile organic compounds even further below health comparison values, most below the analytical detection limits, see Table 2 (10).
The nearest downgradient drinking water well (that withdraws water from the Waipahu Basal Aquifer) is the Hawaii Country Club well (USGS number 2603-01) (1.5 miles away). Analytical results of samples taken from this well before 1993 did not find EDB or DBCP above the detection limits of 0.1 µg/L and 0.05 µg/L respectively (10,11). The Safe Drinking Water Branch, HDOH, obtained a sample from the Hawaii Country Club well on October 21, 1993. The analytical results of this sample found DBCP at 0.05 µg/L (18). EDB was below detection limits. Because the groundwater monitoring program at the Del Monte Oahu Plantation has not delineated the extent of the site-related groundwater contamination, it is not possible to determine whether the DBCP detected in the Hawaii Country Club well is site-related.
The next nearest downgradient drinking water wells are the Kunia II wells (USGS number 2402-01) (approximately 4.5 miles away). Previous HDOH analyses of samples taken from these wells found DBCP below 0.04 µg/L (18).
| Table 2 - Environmental Contaminants Detected in the Navy Well Number 3 (United States Geological Survey [USGS] number 2803-05) and Field Well Number 4 (USGS number 2803-07) and Comparison Values (10,17) | ||||
| Contaminant | Range in the Drinking Water Wells, Before Treatment (µg/L) | Range in the Drinking Water After Treatment (µg/L) | Comparison Value for Ingestion (µg/L)* | Comparison Value Source* |
| Trans-1,2-Dichloroethene | <0.05-0.3 | <0.05 | 100 | LTHA |
| Cis-1,2-Dichloroethene | <0.05-0.24 | <0.05 | 70 | LTHA |
| Carbon Tetrachloride | <0.06-1.4 | <0.05-0.16 | 2.1 | CREG# |
| Trichloroethylene | 0.95-7.7 | <0.05 | 21 | CREG# |
| 1,2,3-Trichloropropane | <0.05-0.34 | <0.16 | 40 | LTHA |
| * - See Appendix 2 for a description of the comparison values and their sources.
# - The lifetime exposure CREG has been adjusted to reflect only 10 years of exposure. µg/L - micrograms of contaminant per liter of water | ||||
Analytical results of subsurface soil samples taken from boring numbers 5B, 6NA, 6C, 7, 8, 8B, 10, and 10A indicate that EDB or DBCP in the subsurface soils have not moved beyond the contaminated areas (i.e., Spill Area and Drum Storage Area). Only one sample was found to contain EDB above the health-based comparison value of 8 µg/Kg (290 µg/Kg in bore hole number 8B at 40 to 42 feet below the surface) (10,11).
No surface soil (the top 3 inches of soil) or surface water samples were taken in the gully/creek northeast of the two contamination areas (see Appendix 1, Figure 1). However, both EDB and DBCP tend to volatilize (move out of surface soils and surface water into the air) very rapidly (19,20). Therefore, it is not likely that EDB and DBCP would remain in the surface soils or surface water in the gully.
Laboratory tests indicate that EDB and DBCP do not accumulate in fish or plants (19,20). Therefore, it is not likely that foodstuffs would be contaminated with site-related contaminants.
C. Quality Assurance And Quality Control
ATSDR was not able to obtain quality assurance and quality control (QA/QC) information for the data presented in this public health assessment. However, several samples were sent to different laboratories (i.e., Del Monte, HDOH, and University of Hawaii) (10,11). The analytical results for these split samples were comparable. This comparability would tend to indicate that data submitted to ATSDR is truly reflective of the conditions at the Del Monte Oahu Plantation NPL site. However, it would be preferable to have a complete QA/QC package for all of the environmental samples taken at this site.
As discussed in the On-Site Contamination section, none of the environmental samples taken at the Del Monte Oahu Plantation NPL site have been analyzed for any contaminants besides EDB, DBCP, and metals. Therefore, it is not possible to determine whether any of the other pesticides or the diluting fluids (e.g., diesel fuel, paint thinner, and white gas) used at the Del Monte Oahu Plantation have contaminated the environment.
The conclusions presented in this public health assessment are based in part on the data presented. The validity of the conclusions, therefore, depends on the accuracy and reliability of the data provided.
As discussed above, the contaminated soils at the two source areas (Spill Area and Drum Storage Area) have been removed. A pit about 60-feet deep is all that remains of the removal action. The pit is surrounded by a 6-foot fence and the gate is locked. The fence should prevent people from falling into the pit. Therefore, there are no physical or other hazards at the Del Monte Oahu Plantation NPL site, except those normally found at a plantation.
E. Review of Toxic Chemical Release Inventory (TRI) Data
To identify possible facilities that could contribute to the contamination at the Del Monte Oahu Plantation NPL site, ATSDR searched the 1987 to 1991 files of the Toxic Chemical Release Inventory (TRI) databases for the zip code where the site is located (96759) (21). TRI was developed by the EPA from chemical release (air, water, and soil) information provided by certain industries.
Several limitations of TRI data should be noted. The air release data in TRI might be estimates or actual measurements. Many of the reported data are estimates based on conservative (overestimated) scenarios. Consequently, the levels of emissions recorded in TRI are often biased on the high side. In addition, reporting is restricted to specific chemicals that are used or released above specified amounts. Finally, it is believed there have been and still are industries that do not report releases. Representatives of smaller industries might not be aware that reporting requirements exist or that they are responsible for such reports (22).
No environmental discharges of site-related chemicals were reported in the TRI for the Del Monte Oahu Plantation zip code (21).
In this section of the public health assessment, the possible environmental exposure pathways are evaluated to help determine whether individuals have been, are being, or will be exposed to site-related contaminants. The pathway analysis consists of five elements:
An environmental exposure pathway is considered complete when there is good evidence that all five elements exist (23). The presence of a completed pathway indicates that human exposure to contaminants has occurred in the past, is occurring, or will occur in the future. When one or more of the five elements of an exposure pathway is missing, that pathway is considered potential. The presence of a potential exposure pathway indicates that human exposure to contaminants could have occurred in the past, could be occurring, or could occur in the future. An exposure pathway can be eliminated from consideration if at least one of the five elements is missing and will never be present. If there is uncertainty about the site-relatedness of the contaminants of concern in an exposure pathway, the pathway will be evaluated as if the contaminants were site-related.
The completed, potential, and no known environmental exposure pathways are discussed below. In addition, Tables 3 and 4 present the estimates of the number of exposed individuals at the Del Monte Oahu Plantation National Priorities List (NPL) site. The population estimates are based upon the information contained in a 1982 State of Hawaii health study (3) and information collected during the January 1994 ATSDR site visit.
A. Completed Environmental Exposure Pathways
There is good evidence that people were exposed (ingestion, inhalation, and skin contact) in the past to site-related contaminants via the Kunia drinking water distribution system. Before 1980, drinking water for Kunia was obtained from one well (i.e., the Kunia well - United States Geological Survey [USGS] number 2703-01). Analytical results of water samples taken from the Kunia well indicate that ethylene dibromide (EDB) and 1,2-dibromo-3-chloropropane (DBCP) were in the well and thereby the Kunia drinking water distribution system in 1980 (1). Tap water samples were not taken to confirm that EDB or DBCP was in the drinking water in the Kunia homes. However, it is reasonable to assume that EDB and DBCP were in the tap water of the Kunia homes. The contaminated well was disconnected from the Kunia drinking water distribution system on April 25, 1980 (24). Since then, drinking water has been provided to Kunia from wells (i.e., the Navy Well Number 3 [USGS number 2803-05] and Field Well Number 4 [USGS number 2803-07]) that do not contain any contamination above health-based comparison values.
Multiple pump tests were conducted on the Kunia well after it was disconnected from the Kunia drinking water distribution system. Water samples were taken at different times while the pump was running. The analytical results of these samples indicate that the highest EDB and DBCP concentrations came out of the well within the first quarter hour of pumping. The initial concentrations varied from 20 to 109 micrograms of EDB per liter of water (µg/L) (average of 39 µg/L) and 2 to 14 µg/L (average of 4 µg/L) for DBCP (11). As the pump ran, the EDB and DBCP concentrations rapidly fell to levels around 1 µg/L (11). During normal operations (before 1980), the Kunia well normally ran for several hours per day, and the well pumped the water into the Kunia storage tank. This information indicates that the people living at Kunia were exposed to concentrations of EDB and DBCP well below the maximum levels detected. It is likely that the time weighted average concentration of EDB and DBCP in the Kunia drinking water distribution system was in the neighborhood of 1 µg/L.
It is not possible to determine precisely when the Kunia well became contaminated with EDB and DBCP. Groundwater monitoring data indicate that the bulk of the EDB and DBCP groundwater contamination is located in the upper aquifer. In order to contaminate the Kunia well, EDB and DBCP would have had to migrate first through the soil at the Drum Storage Area, through the upper groundwater aquifer, through the aquitard separating the upper and deep aquifers (approximately 680 feet thick), and finally into the Waipahu Basal Aquifer, from which the Kunia well pumps water, (approximately 830 feet below the surface). This migration pathway could take many years, because groundwater within the Del Monte Oahu Plantation does not move down easily through these layers of soil and rock, traveling approximately 0.05 feet per day (11). Analytical results of a Kunia water sample taken in 1977 indicated that EDB was not present in the well water above 0.5 µg/L (1). However, this sample was taken after the Kunia well pump had been running for several hours. In 1980, EDB and DBCP were detected in samples taken shortly after the Kunia well pump was turned on (1). Therefore, it is possible that EDB and/or DBCP were present in the Kunia well prior to 1977. Because the plantation started to use EDB in the mid-1940s and EDB would move slowly through the layers of soil and rock above the Waipahu Basal Aquifer from which the Kunia well pumps water, it is unlikely that the EDB or DBCP would have entered the Kunia well before the 1960s. Much higher concentrations of EDB and DBCP would have been detected in the Kunia well if the contaminants had entered the well before 1960. No matter when EDB or DBCP entered the well, it is likely that the initial concentrations would have been well below health comparison values (i.e., 0.0004 µg/L for EDB and 0.2 µg/L for DBCP). The EDB and DBCP Kunia well concentrations would have slowly increased over time until the late 1970s when the concentrations in the well water might have averaged around 1 µg/L.
| Table 3 - Completed Environmental Exposure Pathways at the Del Monte Oahu Plantation National Priorities List Site, Hawaii | ||||||
| Pathway Name | Point of Exposure | Route of Exposure | Exposed Population | Time of Exposure | Contaminants of Concern | Estimated Exposed Population |
| Kunia Drinking Water | Drinking Water | Ingestion, Inhalation, Skin Contact |
People living at Kunia and working at the Del Monte Pineapple Plantation | Past | Ethylene Dibromide & 1,2-Dibromo-3-Chloropropane | 738 |
| Table 4 - Potential Environmental Exposure Pathways at the Del Monte Oahu Planation National Priorities List Site, Hawaii | ||||||
| Pathway Name | Point of Exposure | Route of Exposure | Exposed Population | Time of Exposure | Contaminants of Concern | Estimated Exposed Population |
| Future Groundwater Migration | Drinking Water Wells Downgradient from the Plantation | Ingestion, Inhalation, Skin Contact | People Who Obtain Drinking Water from Downgradient Wells | Future | Ethylene Dibromide & 1,2-Dibromo-3-Chloropropane | Unknown |
| Plantation and Remedial Workers | Occupational during Subsurface Soil Excavation and Normal Plantation Activities | Ingestion, Inhalation, Skin Contact | Remedial Workers During Subsurface Soil Excavation and EDB Application on the Pineapple Fields | Past (The contaminants are no longer used at the planation.) | Ethylene Dibromide & 1,2-Dibromo-3-Chloropropane | Unknown |
It has been estimated that the 1980 total population of Kunia was 738. All of those people obtained their drinking water from the Kunia well. Therefore, the approximate size of the exposed population for this environmental exposure pathway is 738.
B. Potential Environmental Exposure Pathways
People could potentially be exposed (ingestion, inhalation, and skin contact) to site-related contaminants because of future migration of contaminated groundwater in the Waipahu Basal Aquifer. In addition, plantation workers and remedial workers (people who removed the subsurface soil contamination) might have been exposed (ingestion, inhalation, and skin contact) to the subsurface soil contamination before and during the removal action.
1. Future Groundwater Migration
The total extent of EDB or DBCP groundwater contamination has not be determined for the upper or Waipahu Basal Aquifers. Because the EDB and DBCP was mixed with diesel fuel, paint thinner, or "white gas;" it is likely the contaminants could have migrated more extensively than would have occurred if EDB and DBCP were mixed with water. Only three upper aquifer wells have been sampled. These wells are not sufficient to determine the vertical and horizontal spread of the contaminants. The Kunia well is the only Waipahu Basal Aquifer well which has been sampled with any regularity. Additional monitoring wells might be needed to determine the vertical and horizontal extent of EDB and DBCP contamination.
Because the total extent of EDB or DBCP groundwater contamination in the upper and Waipahu Basal Aquifers is not known, it is not possible to determine whether the Del Monte groundwater pumping activities are capturing all of the site-related groundwater contamination. If the Del Monte groundwater pumping activities are not stopping the spread of contaminants from the site, EDB or DBCP could, in the future, migrate into drinking water wells at levels of public health concern downgradient from the NPL site.
Analytical results of water samples taken from the nearest downgradient drinking water well indicate the presence of DBCP in that water. Because the groundwater monitoring program at the Del Monte Oahu Plantation has not delineated the extent of the site-related groundwater contamination, it is not possible to determine whether the DBCP detected in the Hawaii Country Club well is site-related.
2. Plantation and Remedial Workers
Plantation and remedial workers might have been exposed in the past to the subsurface soil contamination when the soil was excavated or spread on the pineapple field. The extent of exposure would depend upon what personal protection equipment the workers wore (i.e., gloves, protective clothing, and respirator); the length of contact; and the amount of contaminated soil ingested, inhaled, and accumulated on the skin.
It is reported that, at a minimum, the remedial workers wore gloves and respirators during the excavation and spreading of the contaminated subsurface soil. These types of personal protective equipment would significantly reduce the remedial workers' exposure to EDB and DBCP. However, EDB and DBCP can be absorbed through the skin. Therefore, it is possible that the remedial workers might have been exposed to EDB and DBCP. The amount of exposure would depend upon how much contaminated soil came in contact with the skin of the remedial workers, how long the contaminated soil stayed on the workers' skin, and how freely EDB and DBCP moved from the soil and through the skin.
Plantation workers not involved with the excavation of the contaminated subsurface soil might have come in contact with the contaminated soil after it had been spread on the pineapple fields. Because the contaminated subsurface soil was spread in thin layers and EDB and DBCP do not stay very long in surface soil (both volatilize very rapidly from surface soil or are degraded by the sun and natural soil microorganisms), it is likely that any exposure to site-related contaminants was small and brief.
As discussed in the Background section of this public health assessment, EDB was applied to the pineapple fields just before the fields were replanted. As the EDB was injected into the soil, a thin plastic mulch film was automatically placed on top of the injection trench. The plastic mulch film was marked with plant spacing intervals. The pineapple crowns were then planted through the markings on the plastic mulch film. According to Del Monte, EDB was not normally applied to the pineapple fields when the pineapples were flowering or when fruit was developing. Pest control chemicals were applied only in response to a pest outbreak. These EDB injection, planting, and application procedures should have reduced the potential for plantation worker exposures to EDB.
The planation workers who had the greatest opportunity for exposure to EDB and DBCP were those workers involved with the EDB applications to the pineapple fields (unrelated to the NPL site). The extent of exposure would depend upon what personal protection equipment the workers wore (i.e., gloves, protective clothing, and respirator); the length of contact; and the amount of pesticide ingested, inhaled, and accumulated on the skin. During the ATSDR public availability sessions, Del Monte workers indicated that they normally wore gloves and respirators. Therefore, it is possible that the EDB-application plantation workers might not have been exposed to significant amounts of EDB and DBCP. The amount of exposure would depend upon how much of the pesticide came in contact with the skin of the EDB application workers, how long the pesticide stayed on the workers' skin, and how freely EDB and DBCP moved through the skin.
ATSDR is not able to estimate accurately the amount of exposure remedial workers or plantation workers had to EDB or DBCP at the NPL site. However, the available information discussed above tends to indicate that remedial workers' and plantation workers' exposures might not have been very frequent or above long-term health comparison levels.
C. No Known Environmental Exposure Pathways
Because EDB and DBCP in surface soil and surface waters tend to evaporate rapidly and be degraded, it is unlikely that people would have been exposed to significant amounts (above health based comparison values) of EDB or DBCP in these two environmental media. It is also unlikely that people would have been exposed to significant amounts of EDB or DBCP in the air because the contaminants were not frequently discharged to the air.
EDB and DBCP are not known to accumulate in plants and animals. Therefore, it is unlikely people were exposed to site-related contaminants in food.
In this section, ATSDR discusses health effects of chemicals to which people were exposed on-site, evaluates available health studies, and addresses specific community health concerns.
To determine whether adverse health effects might result from exposure, ATSDR staff members begin by estimating daily exposure doses for each contaminant of concern. The estimated exposure dose is then compared to a minimal risk level (MRL), which is an estimate of daily exposure to a contaminant below which noncancer adverse health effects are unlikely to occur. To develop the MRL, ATSDR staff members rely on information gained through scientific study of the effects of exposure to contaminants in people and animals. If an exposure dose exceeds an MRL, or if no MRL has been developed, the estimated exposure dose is then compared to doses that resulted in adverse health effects in people or experimental animals, as described in the literature. This comparison takes into account differences among people, as well as the uncertainties in comparing animals to people.
In the United States population as a whole, cancer occurs in one in three individuals (25). It is very difficult for scientists to determine who will develop cancer, but we do know that exposure to some contaminants can increase the chances (or risk) of a person's developing cancer. Even if an individual develops cancer, scientists and physicians generally can not establish the cause of the person's cancer. To determine whether exposure at this site might cause cancer, the increased cancer risk is estimated using the estimated exposure dose and a slope factor. The cancer slope factor is developed by the U.S. Environmental Protection Agency (EPA).
There is good evidence that people were exposed (ingestion, inhalation and skin contact) to ethylene dibromide (EDB) and 1,2-dibromo-3-chloropropane (DBCP) via the Kunia drinking water distribution system. ATSDR staff members evaluated the toxicological implications of exposure to EDB and DBCP in drinking water. To estimate exposure doses, ATSDR staff assumed that adults weigh 70 kilograms (a kilogram is approximately 2.2 pounds) and young children weigh 10 kilograms, and that adults drink 2 liters (a liter is approximately a quart) of water a day, while young children drink 1 liter of water a day. As discussed in the Pathways Analyses section, while the maximum EDB and DBCP levels measured in the Kunia well (United States Geological Survey [USGS] number 2703-01) were 300 and 14 micrograms per liter (µg/L), respectively, it is likely that the time-weighted average concentrations of EDB and DBCP in the Kunia drinking water distribution system were around 1 µg/L in the late 1970s. ATSDR staff used the 1 µg/L value to estimate exposure doses. Furthermore, due to the unlikelihood that EDB and DBCP entered the Kunia well before the 1960s, coupled with the disconnection of the Kunia well in 1980, ATSDR staff members considered a 20-year maximum exposure period (see the discussion in the Pathways Analysis section).
Because ATSDR is not able to estimate accurately the amount of exposure remedial workers or plantation worker had to EDB or DBCP, health effects on workers will not be discussed further. However, information provided to ATSDR indicates that the remedial workers wore personal protective equipment that would have significantly reduced the remedial workers' exposure to site-related contaminants. Plantation workers are not likely to have been exposed to significant levels of site-related contaminants because EDB and DBCP do not remain very long in surface soil (see the discussions under Potential Environmental Exposure Pathways).
1. Ethylene Dibromide (EDB)
EDB has been shown in experiments to cause cancer in animals. However, it is not clear whether EDB can cause cancer in people. Therefore, EPA classifies EDB as a probable human carcinogen. Based on the exposure doses estimated at this site, there is a no apparent increased risk of cancer for people who drank the Kunia well water. EDB probably volatilized in transit from the well to the Kunia water storage tank and from the storage tank to the drinking water taps in the Kunia homes. This volatilization resulted in lower levels of EDB at the tap than in the well. In addition, the level of EDB contamination in the 1960s was likely to have been considerably lower than in the late 1970s. Therefore, it is very unlikely that anyone will develop cancer because of site contamination.
Based on animal studies, other health effects after exposure to EDB might include damage to sperm, liver, and kidney. While ATSDR has not determined an MRL for these effects, the effects occurred in animals exposed to EDB at concentrations 10,000 to 100,000 times higher than those at this site (19). Therefore, it is unlikely anyone became ill because of the EDB in the Kunia drinking water.
2. 1,2-Dibromo-3-Chloropropane (DBCP)
Studies of people who worked in chemical factories that produced DBCP showed that the main harmful effect is on male reproductive organs (20). However, no adverse reproductive effects were seen in people who drank water contaminated with DBCP at levels similar to that found at the Del Monte Oahu Plantation. Wong et al. conducted epidemiologic evaluation of the population exposed to DBCP-contaminated drinking water in Fresno County, California (26). Their study did not find any change in birth rates. Therefore, adverse health effects related to DBCP at the site are not expected.
Animal studies indicate that DBCP might be a possible human carcinogen. However, scientific studies of workers exposed to DBCP have not been able to determine whether DBCP causes cancer in people (20). In addition, Wong et al. also evaluated whether mortality rates for gastric cancer and leukemia were elevated in the Fresno County population exposed to DBCP in drinking water (27). The Wong study did not find any correlation between the mortality rates and DBCP drinking water exposures. Similarly, case-control analysis of gastric cancer and leukemia incidence revealed no correlations with exposure. Therefore, it is unlikely that anyone will develop cancer because of site contamination.
B. Health Outcome Data Evaluation
ATSDR staff reviewed the series of epidemiologic health studies (3, 4, 5, 6, 7, 8, and 9) examining Kunia residents' health, that were conducted following the 1980 discovery of EDB in the Kunia well. Epidemiologic studies are studies which examine the amount and type of disease in a population. Typically, the disease in question is one that exists in populations regardless of the people's exposures, so epidemiologists statistically analyze the number of people in a population with a disease to see if it is higher than normal. In this way, the studies try to answer whether there is an increase in a type of disease in a population associated with exposure.
Epidemiology studies have inherent shortcomings. Generally, one study can not determine cause and effect. One study can only point to an association. The numbers might show that, for the same number of people who do and do not have disease "X," a higher number of people who have the disease were exposed to chemical "Y" than people who do not have the disease. However, that does not prove that chemical "Y" causes disease "X"). It takes several epidemiologic studies along with animal studies before a cause and effect relationship can be determined. In epidemiology studies, the number of people with a disease is considered with respect to the size of the whole population. Because the analysis is performed on the population and not the individual, epidemiology studies can not address whether a specific individual's disease occurred because of exposure or whether that individual would have otherwise developed that disease. For an epidemiologic study to be meaningful, it must evaluate a minimum number of people. The study population size is inversely related to the number of people who normally would get the disease under consideration (i.e., the rarer the disease, the more people needed in the study). If the study population is too small, epidemiology cannot be used to answer questions about exposure and health. In such a case, it might be impossible to answer those questions.
The rates of various diseases in the Kunia population were compared to the rates of the same diseases in a nearby community, Poamoho. Poamoho was chosen because of its ethnic and socioeconomic similarities to Kunia, yet the drinking water in Poamoho was found to be free of EDB and DBCP contamination. These important similarities and differences meant Poamoho could be considered the standard in determining normal numbers of persons with the disease. People who worked at Del Monte were analyzed separately to determine possible health effects of strictly work-related exposure. One problem with all the Kunia health studies is that the numbers people in the studies are low. This made it very difficult to determine whether any adverse health outcomes occurred at Kunia.
Because the toxicologic literature suggests EDB and DBCP exposure might be associated with cancer and adverse reproductive effects, the Kunia studies are discussed regarding their implications towards general health effects, cancer, and reproductive function.
1. Studies Examining General Health Effects
The "Kunia Study: Phase I Medical Records Survey of Kunia and Poamoho Populations" (4); the "Health Assessment of a Community with Pesticide Contaminated Drinking Water: Part I. Household Health Interview Survey" (3); and the "Health Assessment of Infants and Children Exposed to Water Contaminated with DBCP and EDB" (6) examine general health effects of exposure. Study 4 is based on medical records review; study 3 relies on interviews with household members; and study 6 uses interviews, physical exams, and laboratory tests.
All three studies conclude that kidney, liver, and intestine -- organs that have been reported to be affected by exposure -- did not appear to be affected by the EDB and DBCP drinking water contamination. Studies 4 and 6 conclude that the health status of Kunia adults and children is not significantly different than that of Poamoho's. Short-term diseases (which, in the absence of complications, usually run a short, self-limited course) and long-term diseases (chronic problems, such as diabetes) were evaluated, but neither cancer nor reproductive function was evaluated. Study 3 found that Kunia residents and workers had a higher influenza rate and lower respiratory disease rate than Poamoho residents. Since that study is based on interviews, and since people define the flu and respiratory diseases differently, it is unclear what is being measured. Furthermore, flu is not related to exposure to EDB and DBCP. Finally, study 3 indicates the Kunia residents and workers reported they had more neoplasms (cancer, tumors, etc.) than Poamoho residents. However, study 4, which is based on medical records, found no significant difference in rates of neoplasms. Because of the increased rate found in study 3, additional studies were conducted and are discussed below.
2. Studies Examining Cancer
The "Health Assessment of a Community with Pesticide Contaminated Drinking Water: Part II. Incidence of Malignant Neoplasms" (5) examines cancer rates. Because cancer can result from chromosomal damage, the "Health Assessment of Infants and Children Exposed to Water Contaminated with DBCP and EDB" (6) and the "Kunia Study: Assessment of Chromosome Damage by Environmental Exposure to DBCP and EDB" (8) are also discussed in this section.
Study 5 is based on data found in the Hawaii Tumor Registry. It concludes that the cancer rate during 1977 to 1979 was not significantly greater in the Kunia residents and workers than in Poamoho residents or the state as a whole. The overall cancer rates in Kunia versus Poamoho were examined without distinguishing the cancer sites (which body part has the cancer). Because particular carcinogens cause cancer in particular sites, that kind of analysis might not be appropriate. Also, the very small numbers of people with cancer, as well as the absence of information on the people who moved away, make the validity of the statistical analysis questionable. Furthermore, because cancer has a latency period of (might not show up for) about 10 years, the study might have been conducted too early to identify carcinogenic effects of exposure.
Study 5 also examines whether there are differences in cancer rates in Kunia before and after the EDB spill in April 1977. As discussed in the Pathways Analysis section, it is likely that the well was contaminated before the spill, and that the apparent sudden increase in contamination in 1980 is not a reflection of the spill and does not represent a sudden increase in exposure. Therefore, comparing cancer rates before and after the spill probably does not identify any changes due to exposure. ATSDR staff members consider the sections of study 5 that compare rates before and after April 1977, irrelevant.
Studies 6 and 8 investigate possible chromosomal effects (gaps, breaks, instability and abnormality) in exposed children through laboratory examination of specimens. No significant differences were found between the chromosomes of Kunia and Poamoho children.
3. Studies Examining Reproductive Function
The "Kunia Study: Phase II Pregnancy Wastage" (7) and the "Assessment of Effects on Fertility in a Population Exposed to EDB and DBCP" (9) examine effects of exposure on reproductive function. Study 7 uses vital statistics information to examine whether there was an association between exposure of at least one parent and reproductive outcome (including birth rate, fetal/neonatal death, birth injury, and congenital malformation). The Poamoho population was used as a control population in these studies. Because of the small numbers of pregnancies and a high rate of intentional pregnancy termination, the authors conclude that a meaningful interpretation of the data is impossible. In this study, they also analyze birth weight data before exposure started (October 1974 to March 1977) and after exposure began (April 1977 through December 1979). As discussed above, ATSDR staff members consider this type of analysis irrelevant because the Kunia well was probably contaminated prior to 1977.
Study 9 relies on laboratory analysis of specimens donated by Kunia and Poamoho men who were not occupationally exposed and who were occupationally exposed. The men's blood was analyzed for levels of the hormones testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH). The hormone levels were not significantly different among the groups. Sperm were examined for abnormalities and absolute levels (sperm count, percentage motile, and morphology), and were tested for fertility. The results suggest that the level of exposure to EDB and DBCP did not result in a significant impairment of fertility. The authors also discuss some individuals' health conditions but, as described above, epidemiology studies cannot address the association between an individual's health status and exposure; they can only examine population disease rates.
C. Community Health Concerns Evaluation
At the ATSDR-sponsored public availability meetings in Wahiawa on January 25 and 26, 1994, several community members raised general concerns about long-term health effects related to exposure to contaminants on the site. They were particularly concerned about the effects on the health of children and fetuses. Community members also telephoned ATSDR staff members to express concerns about reproductive effects in men exposed to the fumigants used to control nematodes that infest pineapple plants. In addition, ATSDR was asked to try to determine whether arsenic poisoning could be associated with the Del Monte Oahu Plantation National Priorities List (NPL) site. These concerns are addressed in this section.
1. What are the long-term health effects associated with our exposures to EDB and DBCP?
RESPONSE
Exposure to site-related contaminants ceased in April 1980 with the disconnection of the Kunia well. No health effects are expected because of the EDB and DBCP exposures. Furthermore, if a noncancer health effect did not occur at the time of or shortly after exposure, it is extremely unlikely to show up in the long term.
It is suspected that EDB can cause cancer in people. However, based on the exposure doses estimated at this site, there is a no apparent increased risk of cancer for people who drank the Kunia well water. EDB probably volatilized in transit from the well to the Kunia water storage tank and from the storage tank to the drinking water taps in the Kunia homes. This volatilization resulted in lower levels of EDB at the tap than in the well. In addition, the level of EDB contamination in the 1960s was likely to have been considerably lower than in the late 1970s. Therefore, it is very unlikely that anyone will develop cancer because of site contamination.
Animal studies indicate that DBCP might be a possible human carcinogen. However, scientific studies of workers exposed to DBCP have not been able to determine whether DBCP causes cancer in people (20). In addition, Wong et al. evaluated whether mortality rates for gastric cancer and leukemia were elevated in the Fresno County population exposed to DBCP in drinking water, a situation similar to the situation in Kunia (27). The Wong study did not find any correlation between the mortality rates and DBCP drinking water exposures. Similarly, case-control analysis of gastric cancer and leukemia incidence revealed no correlations with exposure. Therefore, it is unlikely that anyone will develop cancer because of site contamination.
2. What are the possible health effects of EDB and DBCP exposures for children and fetuses?
RESPONSE
No health effects are expected in children because of the exposures to EDB and DBCP in the Kunia drinking water. Health studies 6 and 8, which specifically investigate health effects of exposure in children, confirm that expectation. No significant differences in general health effects or in amount of chromosomal damage could be found when comparing Kunia children with Poamoho children, indicating that exposure apparently did not affect the Kunia children's health. Furthermore, as stated above, if a noncancer health effect did not occur at the time of or shortly after exposure, it is extremely unlikely to show up in the long term.
It is not known what effect oral exposure to EDB has on fetuses, because no animal or human studies regarding that question could be located (19). However, study 7 examined reproductive outcomes and reports that, of 31 pregnancies in Kunia in 1977 through 1979, there were no birth defects (congenital malformations) reported.
3. What are the possible health effects of EDB and DBCP exposures on the male reproductive system?
RESPONSE
Studies indicate that EDB affects sperm in bulls at levels significantly higher than what Kunia residents might have received (19). No studies regarding reproductive effects of EDB exposure in people could be located. Numerous studies of people exposed to DBCP at work (typically workers at chemical factories) and of animals suggest that DBCP affects sperm (20). The epidemiology studies of men exposed at work indicate that fertility drops during exposure, but that the damage to sperm production is reversible if the exposure is of short enough duration and to low enough concentrations (28,29). Levels of exposure that resulted in irreversible damage versus reversible damage were not given, but both appeared to be significantly higher than what the Kunia residents were exposed to. Based on those studies, it is not expected that site-related exposures would have affected male fertility. Study 9 confirms this expectation because it suggests that the level of exposure to EDB and DBCP did not result in a significant impairment of male fertility.
4. Could someone have developed arsenic poisoning from the Kunia drinking water?
RESPONSE
Analytical results of samples taken from the Kunia Well (United States Geological Survey
[USGS] number 2703-01), Navy Well Number 3 (USGS number 2803-05), and Field Well
Number 4 (USGS number 2803-07) indicate that the well water does not contain arsenic above
levels that could have resulted in arsenic poisoning. The analytical results did not find arsenic in
these wells above the safe drinking water standard of 50 µg/L. Therefore, it is unlikely someone
would have developed arsenic poisoning as a result of the drinking water supply at Kunia.
