PUBLIC HEALTH ASSESSMENT
DEL MONTE CORPORATION
KUNIA, HONOLULU COUNTY, HAWAII
In order to determine what environmental contaminants might be of concern, ATSDR hasevaluated all of the available environmental monitoring data (1977 to present). Environmentaldata were taken from references 10, 11, 12, 13, 14, 15, 16, 17. Comparison values were used as abasis for evaluation of the data and to determine which contaminants should be looked at moreclosely. Comparison values are estimated health-based environmental concentrations belowwhich no known or anticipated adverse effect on the health of persons should occur. The valuesallow adequate margins of safety. Appendix 2 contains descriptions of the comparison valuesused in this public health assessment.
A contaminant is selected for further evaluation if the contaminant concentration in a validenvironmental sample exceeds comparison values. The presence of a contaminant on the lists inthe tables of this section does not mean that either exposure to the contaminant or adverse healtheffects has occurred or will occur. Inclusion in the list indicates only that the potential for humanexposures to the selected contaminants and the potential for adverse human health effects as aresult of any exposures to the selected contaminants are discussed in more detail in later sectionsof 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 (seeAppendix 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 microgramsof EDB per kilogram of soil [µg/Kg] or ppb) was found 30 to 32 feet below the surface at theDrum Storage Area. The highest DBCP subsurface soil contamination (2,964,000 µg/Kg) wasalso 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 systemwas discovered (see Appendix 1 Figure 2 for a depiction of the local groundwater system). Thisupper aquifer is found at 20 to 30 feet below the surface and extends to about 150 feet below thesurface. Because of the soil and rock composition at these depths, this upper aquifer does notyield very much water (less than 10 gallons per minute). Therefore, it is not used for anyirrigation or potable water supplies. Groundwater samples (1981 to present) were taken from soilboring holes number 3, 6, and 9. Groundwater extraction wells were installed in 1981 (wellnumbers 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 since1981. Extraction well number 9X has been the only well which has consistently been able towithdraw water. EDB levels in extraction well number 9X have fallen from a high of 235,000µg/L to about 19 µg/L. DBCP concentrations in extraction well number 9X has fallen from ahigh 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 feetbelow 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. Theanalytical results of the Kunia well samples (more than 400 analyses from 1977 to present) aresummarized 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) abovehealth comparison values. Since the owners of the Del Monte Plantation pumped and monitoredthe 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).
|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*|
|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
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 migratedbeyond the source areas (away from the Spill Area or the Drum Storage Area) or the plantationboundaries. Because pesticide storage and mixing activities occurred at the Drum Storage Areasince the 1940s, it is possible that the upper aquifer EDB and DBCP contamination could havemigrated 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 inthe Waipahu Basal Aquifer.
The two wells that provide drinking water to Kunia (i.e., the Navy Well Number 3 [USGSnumber 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 ofsamples taken from the wells indicate that the water does not contain any contaminants abovehealth comparison values. The analytical results did detect some trace concentrations of volatileorganic compounds (i.e., trans-1,2-dichloroethene, cis-1,2-dichloroethene, carbon tetrachloride,trichloroethylene, and 1,2,3-trichloropropane) (10,17). However, the detected concentrationswere 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 aerationfacility was installed. This tower reduces the concentration of volatile organic compounds evenfurther 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 BasalAquifer) is the Hawaii Country Club well (USGS number 2603-01) (1.5 miles away). Analyticalresults of samples taken from this well before 1993 did not find EDB or DBCP above thedetection limits of 0.1 µg/L and 0.05 µg/L respectively (10,11). The Safe Drinking WaterBranch, HDOH, obtained a sample from the Hawaii Country Club well on October 21, 1993. Theanalytical 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 notdelineated the extent of the site-related groundwater contamination, it is not possible todetermine 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 thesewells found DBCP below 0.04 µg/L (18).
|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*|
|* - 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 thecontaminated areas (i.e., Spill Area and Drum Storage Area). Only one sample was found tocontain EDB above the health-based comparison value of 8 µg/Kg (290 µg/Kg in bore holenumber 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/creeknortheast of the two contamination areas (see Appendix 1, Figure 1). However, both EDB andDBCP 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 orsurface water in the gully.
ATSDR was not able to obtain quality assurance and quality control (QA/QC) information forthe data presented in this public health assessment. However, several samples were sent todifferent 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 theenvironmental samples taken at this site.
As discussed in the On-Site Contamination section, none of the environmental samples taken atthe 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 pesticidesor the diluting fluids (e.g., diesel fuel, paint thinner, and white gas) used at the Del Monte OahuPlantation have contaminated the environment.
The conclusions presented in this public health assessment are based in part on the datapresented. The validity of the conclusions, therefore, depends on the accuracy and reliability ofthe data provided.
As discussed above, the contaminated soils at the two source areas (Spill Area and Drum StorageArea) 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 peoplefrom falling into the pit. Therefore, there are no physical or other hazards at the Del Monte OahuPlantation NPL site, except those normally found at a plantation.
To identify possible facilities that could contribute to the contamination at the Del Monte OahuPlantation NPL site, ATSDR searched the 1987 to 1991 files of the Toxic Chemical ReleaseInventory (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 bycertain industries.
Several limitations of TRI data should be noted. The air release data in TRI might be estimatesor actual measurements. Many of the reported data are estimates based on conservative(overestimated) scenarios. Consequently, the levels of emissions recorded in TRI are oftenbiased on the high side. In addition, reporting is restricted to specific chemicals that are used orreleased above specified amounts. Finally, it is believed there have been and still are industriesthat do not report releases. Representatives of smaller industries might not be aware thatreporting 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 DelMonte Oahu Plantation zip code (21).
In this section of the public health assessment, the possible environmental exposure pathways areevaluated to help determine whether individuals have been, are being, or will be exposed to site-related contaminants. The pathway analysis consists of five elements:
- identifying contaminants of concern possibly related to the site;
- determining that contaminants have been, are being, or will be transported through anenvironmental medium;
- identifying a point of exposure (i.e., a place or situation where people might be exposed to thecontaminated media);
- determining that there is a plausible route of human exposure (i.e., can the contaminant enterthe body?); and
- identifying an exposed population (i.e., how many people, if any are at the point of exposure).
An environmental exposure pathway is considered complete when there is good evidence that allfive elements exist (23). The presence of a completed pathway indicates that human exposure tocontaminants has occurred in the past, is occurring, or will occur in the future. When one ormore of the five elements of an exposure pathway is missing, that pathway is consideredpotential. The presence of a potential exposure pathway indicates that human exposure tocontaminants 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 ismissing and will never be present. If there is uncertainty about the site-relatedness of thecontaminants of concern in an exposure pathway, the pathway will be evaluated as if thecontaminants 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.
There is good evidence that people were exposed (ingestion, inhalation, and skin contact) in thepast 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 StatesGeological Survey [USGS] number 2703-01). Analytical results of water samples taken from theKunia 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 waterdistribution 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 WellNumber 4 [USGS number 2803-07]) that do not contain any contamination above health-basedcomparison values.
Multiple pump tests were conducted on the Kunia well after it was disconnected from the Kuniadrinking water distribution system. Water samples were taken at different times while the pumpwas running. The analytical results of these samples indicate that the highest EDB and DBCPconcentrations 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, theEDB and DBCP concentrations rapidly fell to levels around 1 µg/L (11). During normaloperations (before 1980), the Kunia well normally ran for several hours per day, and the wellpumped the water into the Kunia storage tank. This information indicates that the people livingat Kunia were exposed to concentrations of EDB and DBCP well below the maximum levelsdetected. It is likely that the time weighted average concentration of EDB and DBCP in theKunia 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 EDBand DBCP. Groundwater monitoring data indicate that the bulk of the EDB and DBCPgroundwater contamination is located in the upper aquifer. In order to contaminate the Kuniawell, 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 deepaquifers (approximately 680 feet thick), and finally into the Waipahu Basal Aquifer, from whichthe Kunia well pumps water, (approximately 830 feet below the surface). This migrationpathway 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, thissample 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 Kuniawell 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.
|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, |
|People living at Kunia and working at the Del Monte Pineapple Plantation||Past||Ethylene Dibromide & 1,2-Dibromo-3-Chloropropane||738|
It has been estimated that the 1980 total population of Kunia was 738. All of those peopleobtained their drinking water from the Kunia well. Therefore, the approximate size of theexposed population for this environmental exposure pathway is 738.
People could potentially be exposed (ingestion, inhalation, and skin contact) to site-relatedcontaminants because of future migration of contaminated groundwater in the Waipahu BasalAquifer. In addition, plantation workers and remedial workers (people who removed thesubsurface 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 theupper 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 extensivelythan would have occurred if EDB and DBCP were mixed with water. Only three upper aquiferwells have been sampled. These wells are not sufficient to determine the vertical and horizontalspread of the contaminants. The Kunia well is the only Waipahu Basal Aquifer well which hasbeen sampled with any regularity. Additional monitoring wells might be needed to determine thevertical and horizontal extent of EDB and DBCP contamination.
Because the total extent of EDB or DBCP groundwater contamination in the upper and WaipahuBasal Aquifers is not known, it is not possible to determine whether the Del Monte groundwaterpumping activities are capturing all of the site-related groundwater contamination. If the DelMonte 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 healthconcern downgradient from the NPL site.
Analytical results of water samples taken from the nearest downgradient drinking water wellindicate the presence of DBCP in that water. Because the groundwater monitoring program atthe Del Monte Oahu Plantation has not delineated the extent of the site-related groundwatercontamination, it is not possible to determine whether the DBCP detected in the Hawaii CountryClub well is site-related.
2. Plantation and Remedial Workers
Plantation and remedial workers might have been exposed in the past to the subsurface soilcontamination when the soil was excavated or spread on the pineapple field. The extent ofexposure 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 soilingested, inhaled, and accumulated on the skin.
It is reported that, at a minimum, the remedial workers wore gloves and respirators during theexcavation and spreading of the contaminated subsurface soil. These types of personal protectiveequipment 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 theremedial workers might have been exposed to EDB and DBCP. The amount of exposure woulddepend 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 DBCPmoved from the soil and through the skin.
Plantation workers not involved with the excavation of the contaminated subsurface soil mighthave 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 notstay very long in surface soil (both volatilize very rapidly from surface soil or are degraded by thesun and natural soil microorganisms), it is likely that any exposure to site-related contaminantswas small and brief.
As discussed in the Background section of this public health assessment, EDB was applied to thepineapple fields just before the fields were replanted. As the EDB was injected into the soil, athin plastic mulch film was automatically placed on top of the injection trench. The plasticmulch film was marked with plant spacing intervals. The pineapple crowns were then plantedthrough the markings on the plastic mulch film. According to Del Monte, EDB was not normallyapplied 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 workerexposures to EDB.
The planation workers who had the greatest opportunity for exposure to EDB and DBCP werethose workers involved with the EDB applications to the pineapple fields (unrelated to the NPLsite). The extent of exposure would depend upon what personal protection equipment theworkers wore (i.e., gloves, protective clothing, and respirator); the length of contact; and theamount of pesticide ingested, inhaled, and accumulated on the skin. During the ATSDR publicavailability sessions, Del Monte workers indicated that they normally wore gloves andrespirators. Therefore, it is possible that the EDB-application plantation workers might not havebeen exposed to significant amounts of EDB and DBCP. The amount of exposure would dependupon 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 movedthrough the skin.
ATSDR is not able to estimate accurately the amount of exposure remedial workers or plantationworkers had to EDB or DBCP at the NPL site. However, the available information discussedabove tends to indicate that remedial workers' and plantation workers' exposures might not havebeen very frequent or above long-term health comparison levels.
Because EDB and DBCP in surface soil and surface waters tend to evaporate rapidly and bedegraded, it is unlikely that people would have been exposed to significant amounts (abovehealth based comparison values) of EDB or DBCP in these two environmental media. It is alsounlikely that people would have been exposed to significant amounts of EDB or DBCP in the airbecause the contaminants were not frequently discharged to the air.
EDB and DBCP are not known to accumulate in plants and animals. Therefore, it is unlikelypeople 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 membersbegin by estimating daily exposure doses for each contaminant of concern. The estimatedexposure dose is then compared to a minimal risk level (MRL), which is an estimate of dailyexposure 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 studyof the effects of exposure to contaminants in people and animals. If an exposure dose exceeds anMRL, or if no MRL has been developed, the estimated exposure dose is then compared to dosesthat resulted in adverse health effects in people or experimental animals, as described in theliterature. This comparison takes into account differences among people, as well as theuncertainties in comparing animals to people.
In the United States population as a whole, cancer occurs in one in three individuals (25). It isvery difficult for scientists to determine who will develop cancer, but we do know that exposureto some contaminants can increase the chances (or risk) of a person's developing cancer. Even ifan individual develops cancer, scientists and physicians generally can not establish the cause ofthe person's cancer. To determine whether exposure at this site might cause cancer, the increasedcancer risk is estimated using the estimated exposure dose and a slope factor. The cancer slopefactor is developed by the U.S. Environmental Protection Agency (EPA).
There is good evidence that people were exposed (ingestion, inhalation and skin contact) toethylene dibromide (EDB) and 1,2-dibromo-3-chloropropane (DBCP) via the Kunia drinkingwater distribution system. ATSDR staff members evaluated the toxicological implications ofexposure to EDB and DBCP in drinking water. To estimate exposure doses, ATSDR staffassumed that adults weigh 70 kilograms (a kilogram is approximately 2.2 pounds) and youngchildren weigh 10 kilograms, and that adults drink 2 liters (a liter is approximately a quart) ofwater a day, while young children drink 1 liter of water a day. As discussed in the PathwaysAnalyses 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 perliter (µg/L), respectively, it is likely that the time-weighted average concentrations of EDB andDBCP 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 theunlikelihood that EDB and DBCP entered the Kunia well before the 1960s, coupled with thedisconnection of the Kunia well in 1980, ATSDR staff members considered a 20-year maximumexposure period (see the discussion in the Pathways Analysis section).
Because ATSDR is not able to estimate accurately the amount of exposure remedial workers orplantation 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 personalprotective equipment that would have significantly reduced the remedial workers' exposure tosite-related contaminants. Plantation workers are not likely to have been exposed to significantlevels of site-related contaminants because EDB and DBCP do not remain very long in surfacesoil (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 whetherEDB can cause cancer in people. Therefore, EPA classifies EDB as a probable humancarcinogen. Based on the exposure doses estimated at this site, there is a no apparent increasedrisk of cancer for people who drank the Kunia well water. EDB probably volatilized in transitfrom the well to the Kunia water storage tank and from the storage tank to the drinking watertaps in the Kunia homes. This volatilization resulted in lower levels of EDB at the tap than in thewell. In addition, the level of EDB contamination in the 1960s was likely to have beenconsiderably lower than in the late 1970s. Therefore, it is very unlikely that anyone will developcancer because of site contamination.
Based on animal studies, other health effects after exposure to EDB might include damage tosperm, liver, and kidney. While ATSDR has not determined an MRL for these effects, theeffects occurred in animals exposed to EDB at concentrations 10,000 to 100,000 times higherthan those at this site (19). Therefore, it is unlikely anyone became ill because of the EDB in theKunia drinking water.
2. 1,2-Dibromo-3-Chloropropane (DBCP)
Studies of people who worked in chemical factories that produced DBCP showed that the mainharmful effect is on male reproductive organs (20). However, no adverse reproductive effectswere seen in people who drank water contaminated with DBCP at levels similar to that found atthe Del Monte Oahu Plantation. Wong et al. conducted epidemiologic evaluation of thepopulation 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 toDBCP at the site are not expected.
Animal studies indicate that DBCP might be a possible human carcinogen. However, scientificstudies of workers exposed to DBCP have not been able to determine whether DBCP causescancer in people (20). In addition, Wong et al. also evaluated whether mortality rates for gastriccancer and leukemia were elevated in the Fresno County population exposed to DBCP indrinking water (27). The Wong study did not find any correlation between the mortality ratesand DBCP drinking water exposures. Similarly, case-control analysis of gastric cancer andleukemia incidence revealed no correlations with exposure. Therefore, it is unlikely that anyonewill develop cancer because of site contamination.
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 inthe Kunia well. Epidemiologic studies are studies which examine the amount and type of diseasein a population. Typically, the disease in question is one that exists in populations regardless ofthe people's exposures, so epidemiologists statistically analyze the number of people in apopulation with a disease to see if it is higher than normal. In this way, the studies try to answerwhether 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 causeand effect. One study can only point to an association. The numbers might show that, for thesame number of people who do and do not have disease "X," a higher number of people whohave 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 severalepidemiologic studies along with animal studies before a cause and effect relationship can bedetermined. In epidemiology studies, the number of people with a disease is considered withrespect to the size of the whole population. Because the analysis is performed on the populationand not the individual, epidemiology studies can not address whether a specific individual'sdisease occurred because of exposure or whether that individual would have otherwise developedthat disease. For an epidemiologic study to be meaningful, it must evaluate a minimum numberof people. The study population size is inversely related to the number of people who normallywould get the disease under consideration (i.e., the rarer the disease, the more people needed inthe study). If the study population is too small, epidemiology cannot be used to answer questionsabout 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 samediseases in a nearby community, Poamoho. Poamoho was chosen because of its ethnic andsocioeconomic similarities to Kunia, yet the drinking water in Poamoho was found to be free ofEDB and DBCP contamination. These important similarities and differences meant Poamohocould 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 effectsof strictly work-related exposure. One problem with all the Kunia health studies is that thenumbers people in the studies are low. This made it very difficult to determine whether anyadverse health outcomes occurred at Kunia.
Because the toxicologic literature suggests EDB and DBCP exposure might be associated withcancer and adverse reproductive effects, the Kunia studies are discussed regarding theirimplications 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 ChildrenExposed to Water Contaminated with DBCP and EDB" (6) examine general health effects ofexposure. Study 4 is based on medical records review; study 3 relies on interviews withhousehold 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 beaffected by exposure -- did not appear to be affected by the EDB and DBCP drinking watercontamination. Studies 4 and 6 conclude that the health status of Kunia adults and children is notsignificantly different than that of Poamoho's. Short-term diseases (which, in the absence ofcomplications, 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 respiratorydisease rate than Poamoho residents. Since that study is based on interviews, and since peopledefine 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 theKunia residents and workers reported they had more neoplasms (cancer, tumors, etc.) thanPoamoho residents. However, study 4, which is based on medical records, found no significantdifference in rates of neoplasms. Because of the increased rate found in study 3, additionalstudies 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 fromchromosomal damage, the "Health Assessment of Infants and Children Exposed to WaterContaminated with DBCP and EDB" (6) and the "Kunia Study: Assessment of ChromosomeDamage 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 rateduring 1977 to 1979 was not significantly greater in the Kunia residents and workers than inPoamoho residents or the state as a whole. The overall cancer rates in Kunia versus Poamohowere examined without distinguishing the cancer sites (which body part has the cancer). Becauseparticular carcinogens cause cancer in particular sites, that kind of analysis might not beappropriate. Also, the very small numbers of people with cancer, as well as the absence ofinformation on the people who moved away, make the validity of the statistical analysisquestionable. Furthermore, because cancer has a latency period of (might not show up for) about10 years, the study might have been conducted too early to identify carcinogenic effects ofexposure.
Study 5 also examines whether there are differences in cancer rates in Kunia before and after theEDB spill in April 1977. As discussed in the Pathways Analysis section, it is likely that the wellwas contaminated before the spill, and that the apparent sudden increase in contamination in1980 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 anychanges due to exposure. ATSDR staff members consider the sections of study 5 that comparerates before and after April 1977, irrelevant.
Studies 6 and 8 investigate possible chromosomal effects (gaps, breaks, instability andabnormality) in exposed children through laboratory examination of specimens. No significantdifferences 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 Fertilityin a Population Exposed to EDB and DBCP" (9) examine effects of exposure on reproductivefunction. Study 7 uses vital statistics information to examine whether there was an associationbetween exposure of at least one parent and reproductive outcome (including birth rate,fetal/neonatal death, birth injury, and congenital malformation). The Poamoho population wasused as a control population in these studies. Because of the small numbers of pregnancies and ahigh rate of intentional pregnancy termination, the authors conclude that a meaningfulinterpretation of the data is impossible. In this study, they also analyze birth weight data beforeexposure started (October 1974 to March 1977) and after exposure began (April 1977 throughDecember 1979). As discussed above, ATSDR staff members consider this type of analysisirrelevant because the Kunia well was probably contaminated prior to 1977.
Study 9 relies on laboratory analysis of specimens donated by Kunia and Poamoho men whowere not occupationally exposed and who were occupationally exposed. The men's blood wasanalyzed for levels of the hormones testosterone, luteinizing hormone (LH) and folliclestimulating hormone (FSH). The hormone levels were not significantly different among thegroups. Sperm were examined for abnormalities and absolute levels (sperm count, percentagemotile, and morphology), and were tested for fertility. The results suggest that the level ofexposure to EDB and DBCP did not result in a significant impairment of fertility. The authorsalso discuss some individuals' health conditions but, as described above, epidemiology studiescannot address the association between an individual's health status and exposure; they can onlyexamine population disease rates.
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 toexposure to contaminants on the site. They were particularly concerned about the effects on thehealth of children and fetuses. Community members also telephoned ATSDR staff members toexpress concerns about reproductive effects in men exposed to the fumigants used to controlnematodes that infest pineapple plants. In addition, ATSDR was asked to try to determinewhether arsenic poisoning could be associated with the Del Monte Oahu Plantation NationalPriorities 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?
Exposure to site-related contaminants ceased in April 1980 with the disconnection of the Kuniawell. No health effects are expected because of the EDB and DBCP exposures. Furthermore, ifa noncancer health effect did not occur at the time of or shortly after exposure, it is extremelyunlikely to show up in the long term.
It is suspected that EDB can cause cancer in people. However, based on the exposure dosesestimated at this site, there is a no apparent increased risk of cancer for people who drank theKunia well water. EDB probably volatilized in transit from the well to the Kunia water storagetank and from the storage tank to the drinking water taps in the Kunia homes. This volatilizationresulted in lower levels of EDB at the tap than in the well. In addition, the level of EDBcontamination 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, scientificstudies of workers exposed to DBCP have not been able to determine whether DBCP causescancer in people (20). In addition, Wong et al. evaluated whether mortality rates for gastriccancer and leukemia were elevated in the Fresno County population exposed to DBCP indrinking water, a situation similar to the situation in Kunia (27). The Wong study did not findany 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?
No health effects are expected in children because of the exposures to EDB and DBCP in theKunia drinking water. Health studies 6 and 8, which specifically investigate health effects ofexposure in children, confirm that expectation. No significant differences in general healtheffects or in amount of chromosomal damage could be found when comparing Kunia childrenwith Poamoho children, indicating that exposure apparently did not affect the Kunia children'shealth. Furthermore, as stated above, if a noncancer health effect did not occur at the time of orshortly 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 humanstudies regarding that question could be located (19). However, study 7 examined reproductiveoutcomes and reports that, of 31 pregnancies in Kunia in 1977 through 1979, there were no birthdefects (congenital malformations) reported.
3. What are the possible health effects of EDB and DBCP exposures on the male reproductive system?
Studies indicate that EDB affects sperm in bulls at levels significantly higher than what Kuniaresidents might have received (19). No studies regarding reproductive effects of EDB exposurein people could be located. Numerous studies of people exposed to DBCP at work (typicallyworkers at chemical factories) and of animals suggest that DBCP affects sperm (20). Theepidemiology studies of men exposed at work indicate that fertility drops during exposure, butthat the damage to sperm production is reversible if the exposure is of short enough duration andto low enough concentrations (28,29). Levels of exposure that resulted in irreversible damageversus reversible damage were not given, but both appeared to be significantly higher than whatthe Kunia residents were exposed to. Based on those studies, it is not expected that site-relatedexposures would have affected male fertility. Study 9 confirms this expectation because itsuggests that the level of exposure to EDB and DBCP did not result in a significant impairmentof male fertility.
4. Could someone have developed arsenic poisoning from the Kunia drinking water?
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 WellNumber 4 (USGS number 2803-07) indicate that the well water does not contain arsenic abovelevels that could have resulted in arsenic poisoning. The analytical results did not find arsenic inthese wells above the safe drinking water standard of 50 µg/L. Therefore, it is unlikely someonewould have developed arsenic poisoning as a result of the drinking water supply at Kunia.