PUBLIC HEALTH ASSESSMENT
LOCKWOOD SOLVENT GROUNDWATER PLUME
(a/k/a LOCKWOOD SOLVENT GROUND WATER PLUME)
BILLINGS, YELLOWSTONE COUNTY, MONTANA
About the Site
Sampling by theMontana Departmentof EnvironmentalQuality (DEQ) foundelevated levels ofchlorinated solventsat some homes in the Lomond Lane area of Lockwood. Arearesidents, whose wells contained elevatedlevels of solvents, are now connected to asafe, public water supply through theLockwood Water Users' Association.
Since 1998, the Montana DEQ and theEnvironmental Protection Agency (EPA)have conducted more groundwatersampling. In December 2000, theLockwood Solvent Site became aSuperfund Site and the contaminatedgroundwater is now being addressedthrough the Superfund clean up program,under DEQ's leadership.
Some area residents have expressedconcern about what are safe and properuses of groundwater from contaminatedprivate wells. With summer here and aswe spend more time outdoors, wateryards, and tend gardens, the possibilityof exposure to groundwater increases. This fact sheet provides some answers tocommon questions for people usingcontaminated groundwater from privatewells.
We have written the following generalresponses to be most protective, so eventhough some well water is morecontaminated than others, followingthese recommendations will help ensurethat everyone is protected. We alsorecommend that, whenever possible,residents rely on the public water systemfor your water needs.
Frequently Asked Questions:
- Can I use well water to water mygarden? Is it then safe to eatvegetables from my garden?
- Is it safe for children to play in thesprinklers (well water)?
- Is it safe for me to water my petsand/or livestock with well water?
- Is it safe for me to use well water towash my car?
- Can I use well water to water mylawn? Will it hurt my lawn,flowers or shrubs?
- Can I use well water for my houseplants?
- Can I use well water to fill up ourswimming pool? Is it safe for mykids to swim in it?
- If I do need to be in contact withwell water, what precautions should Itake?
- Is there anything else I can do tolimit exposure to contaminated wellwater?
Yes. There is no evidence that thechlorinated solvents are taken up byplants. Therefore, we believe it issafe to eat vegetables that werewatered with well water.
No. We want to avoid direct skincontact with contaminated well water. Therefore, we recommend using waterfrom the public water system whenchildren are playing in the sprinklers.
No. We recommend using water fromthe public water system when wateringpets and other animals.
Yes, but we recommend that you limitexposure by wearing waterproofgloves, boots and, of course, washyour car outside in the open air soany vapors can easily disperse.
Yes, you can use well water to wateryour lawn, flowers and shrubs and itshouldn't harm them.
Yes. Using wellwater for yourhouseplants shouldnot harm them.
No. We want to avoid direct skincontact with contaminated wellwater, therefore, we recommendusing water from the public watersystem for swimming pools.
You should try to limit your exposure. Wear waterproof gloves and bootsand avoid working in enclosed, poorly-ventilated spaces.
Yes. You could consider closing outyour well. The Montana Departmentof Natural Resources andConservation office in Billings canprovide more information about howto properly abandon a private well. Call Keith Kerbel at 247-4415 orvisit him at 1371 Rimtop Drive,Building IP-9 in Billings.
The Agency for Toxic Substances and Disease Registry (ATSDR) is part of the Public Health Service of the U.S. Government. Our goal is to prevent or mitigate adverse effects on health or quality of life that results from exposure to hazardous substances inthe environment.
What is the TCE Subregistry?
The National Exposure Registry is designed to aidATSDR in assessing if there are health affectsassociated with the low-level, long-term exposuresto hazardous chemicals, such as those identified athazardous waste sites. The Registry data can not beused to determine if the chemical exposures causedhealth problems. However, the baselineinformation, along with the additional informationATSDR will be collecting future, will help ATSDRdetermine if there is an association of adverse healtheffects with the exposures. Using criteria detailedin the Agency's Policies and Procedures forEstablishing a National Registry of PersonsExposed to Hazardous Substances, ATSDRselected those exposed to the chemicaltrichloroethylene (TCE) for the first subregistrybecause of the toxicity, ubiquitousness, and the lackof information on low-level, long-term humanexposure for TCE.
During an initial or baseline interview, 4,834people participated in the Subregistry from 13hazardous waste sites located in Indiana, Michigan,Illinois and Pennsylvania. These sites were selectedbecause there was environmental data available thatdocumented the exposure of the residents. The datacollected at baseline consisted of responses to 26health questions as well as demographic and occupationalinformation. The Registry participants wererecontacted one year after their initial interview,then biennially to update information on their healthstatus. The analyses of the baseline data have beencompleted and the technical and registrant reportshave been written.
What is the Registrant Report?
The Registrant Report is the first report on thehealth of the people who are members of the TCESubregistry. The Registry program is an ongoingeffort; the data analyses will continue as moreinformation becomes available and the resultsreported to the registrants.
For this report, ATSDR compared the healthconditions reported by registrants with healthconditions reported in a nationwide survey of thegeneral populationthe National Health InterviewSurvey (NHIS) conducted by the National Centerfor Health Statistics. ATSDR found that registrantsreported some health conditions at a higher ratethan would have been expected based on thenational norms. Some of the health conditionsshowed higher rates for certain age groups; othershad higher rates only for men or only for women. Cancer rates were not higher compared with thegeneral population. Some of the health conditionswith higher rates are:
Anemia and Other Blood Disorders
What does this mean?
At this time, ATSDR does not know the reason forthese higher rates. There are several possiblereasons for the higher rates, such as exposure toTCE, other chemical exposures at work or home,personal lifestyle choices like smoking or drinkingalcohol, or complications related to other healthconditions. More detailed information is needed onseveral of these reported health conditions toevaluate these reasons. ATSDR will be contactingsome registrants who reported certain healthconditions in the near future to obtain moreinformation and possibly medical records. ATSDRwill look at this information as well as that providedin update interviews and tell registrants about theseresults in future reports. It is possible the resultswill change as more information is obtained.
What happens now?
ATSDR will be contacting some registrants in thenear future for more information about certainconditions reported at baseline. Also, ATSDR willalso call all Registrants this summer to keep theTCE Subregistry up to date. The new informationwill be analyzed and the results reported to theregistrants.
ATSDR does not have enough information abouthealth conditions in the TCE subregistry to makemedical recommendations that are different fromthe good health practices recommendations for thegeneral public. However, ATSDR will provide theresults of this report to area physicians. Registrantswho have particular health concerns may wish tocontact their personal physician.
Where can I get more information?
Dr. Ginger Gist
1600 Clifton Road (MS E-31)
Atlanta, Georgia 30333
A copy of The TCE Subregistry Technical Report,which is a more complete report of the baselineanalysis, is available for your review at a location inyour community.
National Exposure Registry
Trichloroethylene (TCE) Subregistry
Revised Baseline Registrant Report
The Agency for Toxic Substances and Disease Registry (ATSDR) started the trichloroethylene(TCE) subregistry as part of the National Exposure Registry. The goal of the subregistry is tocollect and provide information which will guide ATSDR in exploring whether there may be alink between exposure to TCE and health problems. Information from the first (baseline)interview with subregistry members (registrants) has provided a first step toward this goal. Thisinformation has helped in determining what steps should be taken next.
This is the first report about health conditions to the people who are part of the TCE subregistry. This report on the baseline study is a summary of the TCE Baseline Technical Report, whichgives the details about the survey methods and results from the first interview (baselineinterview) with registrants. The full report is available at locations listed in the cover letter.
Who are the registrants?
Registrants were exposed to TCE through contaminated household water. In the subregistry,there are 4,522 living and 254 deceased registrants. The following is a list of locations and thenumber of addresses at each that are included in the TCE subregistry.
Michigan .......... 121 addresses
Indiana ........... 320 addresses
Illinois .......... 461 addresses
A site in Pennsylvania was added to the TCE subregistry in 1992 and a site in Arizona will beadded this year. The interview data from those sites are not included in this report.
The characteristics of the 4,042 living registrants were:
52% were females
97% were white, average age was 44 years
24% were under 18 years of age
70% of registrants aged 25 years and older graduated from high school
69% were employed full- or part-time
61% were current or ex-smokers
What were the results of the baseline survey?
The health conditions that TCE registrants reported in the first interview were compared with thehealth conditions reported in a nationwide survey of the general population. The results discussedin this report are limited to white registrants because of the small number of people in otherracial groups.
Registrants reported higher rates for some health conditions when compared with the rates seenin the national survey. Table 1 shows the health conditions, by sex and age groups, for whichthere were higher rates reported. Table 1 also displays the number of cases that would have beenexpected using the national survey rates.
TCE registrants reported higher rates for the following conditions:
- Rashes: Higher rates of "skin rashes, eczema, or skin allergies" were reported for both males and females in all age groups.
- Speech Impairment: Higher rates were reported for males and females 9 years of age and younger.
- Hearing Impairment: Higher rates were reported for both males and females 9 years of age and younger.
- Stroke: Higher rates of "the effects of a stroke" were reported for both males and females from 35 through 54 years of age and 65 years of age and older.
- Anemia and Blood Disorders: Higher rates were reported for males 9 years of age and younger, 35 through 44 years, and 55 years of age and older, and females aged 18 through 24 and 35 through 54 years of age.
- Diabetes: Higher rates were reported for females 18 through 24 and 45 through 54 years of age.
- Kidney Disease: Higher rates were reported among females from 55 through 64 years ofage.
- Urinary Tract Disorders: Higher rates were reported among females in 0 through 9, 18through 44, and 55 and over age groups. Higher rates were seen in males from 18through 34 years of age.
Higher rates of cancer were not reported among registrants. However, the rates of all healthoutcomes, including cancer, can change as time passes and therefore, the comparisons with thenational rates may also change.
Does TCE in household water affect health?
Registrants reported a greater number of health problems compared with a national survey of thegeneral U.S. population. The registry data can not be used to determine if TCE `causes' healthproblems. These increased rates might be related to TCE exposure. However, other factorsmight have contributed to these health problems. For example, exposure to chemicals at workand lifestyle factors such as smoking cigarettes and drinking alcohol can affect health. Healthconditions can be due to other illnesses. For example, a hearing loss can be related to earinfections.
There are also some technical issues that must be considered when interpreting the TCEsubregistry data. The wording for some of the TCE subregistry questions did not exactly matchthe wording of the national survey questions. This may have caused the rates to differ. It ispossible that people who know that they have been exposed may be more aware of their healthand seek medical services more often than the general public. In addition, there is very littleenvironmental information. At most subregistry addresses, only one sample was available fromthe wells to document that exposure to TCE occurred. More information is needed to calculatelevels of exposure. ATSDR is going to try to get information that will help address thesetechnical points.
Also, to better understand the health conditions seen in this baseline report, ATSDR needs moredetailed health information. ATSDR will contact the people who reported certain healthconditions and try to determine the exact type of health condition reported and what other factors,if any, might be related to the conditions. As new information is collected from future surveys,the results will be shared with registrants.
What happens now?
ATSDR will contact by telephone those people who reported certain health conditions. Theywill be asked to provide more information about their health, and might be asked to release theirmedical records for review. This new information will be reviewed for the subregistry as awhole; a decision will then be made on what other steps might be needed for health studies. Allregistrants will be informed of these steps.
ATSDR will begin work to try and get the information needed to answer the technical problems. A project is already underway to better define the exposures of the communities on the TCEsubregistry.
This summer, registrants will be contacted to update subregistry files. After the interviews thissummer, interviews will take place every 2 years. The same questions will be included in theinterviews, but there may be some new questions based on the results of the baseline study. Theresults of the updates will be shared with registrants.
The letter that was enclosed with this report gives the time and place of a community meeting sponsored by ATSDR. In that meeting, these results will be discussed and any questionsregistrants may have about the report will be answered. The letter also describes where the fullTCE Baseline Technical Report can be obtained.
What should the registrants do?
If registrants have any concerns about their health, they should consult their personal doctors orother health care providers. ATSDR also plans to give the health care providers in the area acopy of this report and additional medical information.
For information on this report or the TCE Baseline Technical Report, please contact Dr. Je Anne Burg at (404) 639-6202.
|HEALTH CONDITION||SEX||AGE (years)||TOTAL NUMBER OF REGISTRY MEMBERS||NUMBER OF REGISTRY MEMBERS WHO ANSWERED "YES" FOR HEALTH CONDITION (OBSERVED)||NUMBER EXPECTED BASED ON NATIONAL NORMS|
|Skin Rashes||Male and Female||All Ages||3915||318||248|
|Urinary Disorder||Male||18-24 |
This report provides an overview of the Agency for Toxic Substances and Disease Registry(ATSDR) Trichloroethylene (TCE) Subregistry Baseline and Followup activities, and the resultsof a comparison of TCE Subregistry reporting rates of health outcomes with national norms. The TCE Subregistry is one of four chemical-specific subregistries, along with the Benzene,Trichloroethane (TCA), and Dioxin Subregistries, that comprise the National Exposure Registry(NER). The NER is a database composed of names and other relevant information of personswith documented exposure to specific chemicals. The NER was created in response to a mandategiven in the Comprehensive Environmental Response, Compensation, and Liability Act of 1980(11). This mandate was reiterated in the Superfund Amendments and Reauthorization Act of1986 (12).
The purpose of the NER is to assess long-term health consequences of long-term exposure to lowlevels of environmental contaminants (1). One of the goals to accomplish this purpose is toestablish a database that will provide information needed to generate appropriate and validhypotheses for future activities, such as epidemiologic studies. The NER is not a definitivestudy; cause and effect relationships cannot be established using only NER-based information. However, analysis of NER data can assist researchers in identifying health outcomes that warrantconsideration for future studies or activities.
The data files for each chemical-specific subregistry were established at the time baseline datawere collected, updated at each followup, and maintained by ATSDR on an ongoing basis. Atbaseline, information collected from each registrant included environmental data, demographicinformation, smoking and occupational history, and self-reported responses to 25 general healthstatus questions. These same questions are asked at each followup. The first update (Followup1) occurs 1 year after baseline, and subsequent followups occur biennially. At this time, therehave been five followups at the Michigan and Indiana sites; four at the Illinois sites; three at thePennsylvania site; and two at the Arizona site.
The TCE Subregistry Baseline data file includes information collected on 4,986 persons (4,652living, 334 deceased) with documented environmental exposure to TCE, who had resided in 15areas in 5 states (three sites in Michigan, four in Indiana, six in Illinois, one each in Pennsylvaniaand Arizona). TCE registrants were exposed through drinking water from TCE-contaminatedprivate wells. To be eligible for the TCE Subregistry, persons had to have lived in one of theaffected areas for more than 30 days and used the water at an address where the water supply(private wells) was contaminated with TCE. For eligible persons who were deceased at baselineor subsequent followups, death certificates were obtained and pertinent information abstracted. The participation rate for those eligible at baseline exceeded 98% at each site, and participationof approximately 89% of the registrants has been retained at each followup. Most loss ofparticipation is due to inability to locate participants. Less than 2% of losses are because ofrefusal to participate.
The health-outcome rates in the TCE Subregistry Baseline, Followups 1 and 2 data (for all sites),and Followup 3 (for Illinois, Indiana, and Michigan) were compared with composite morbidityrates from the 1989-1994 National Health Interview Survey (NHIS), administered by theNational Center for Health Statistics (NCHS). ATSDR has previously reported results ofcomparisons of TCE Subregistry reporting rates for most health outcomes with appropriate NHISannual files; cancer reporting rates with data files from the National Cancer Institute'sSurveillance, Epidemiology and End Results Program (SEER); mortality rates with nationalmortality data from the NCHS; and TCE Subregistry intrafile comparisons between exposuregroups based on level and duration of exposure (2, 3).
Morbidity data analyses indicated TCE Subregistry registrants had an increased reporting rate forseveral health outcomes, most of which were consistent across data collection points. However,because of small numbers, for some time periods a change of 1 in the number of reports or in thesample size changed the level of statistical significance. The following statistically significantincreases (p.01 significance level) were found:
- Speech impairment and hearing impairment reporting rates for children under 10 years ofage were statistically increased at baseline, but not for the followups. Reporting ratesdecreased for all other age groups.
- Reporting rates for anemia and other blood disorders increased at all collection points,particularly for those aged less than 10 years and people aged 35 through 64 years.
- Stroke was reported in excess at each data collection period. The greatest increases werefor females aged 10 through 54 years and males 25 through 44 years.
- Urinary tract disorders were reported at a higher rate for females in all age groups, and formales aged 10 through 25 years.
- Reported rates for liver problems were elevated or significantly higher for females aged 45 through 64 years; kidney problems were also reported in excess at baseline for femalesaged 55 through 64 years.
- Diabetes rates were higher for females aged 18 through 24 years and 45 through 54 yearsat all reporting periods; there was an overall increase at Followup 3.
- Skin rashes, eczema, and other skin allergies were reported at a higher rate at baseline andFollowup 3; the two youngest age groups (less than 17 years) had the highest rates.
When interpreting statistical results, and planning future activities based on these results, certainlimitations of the TCE Subregistry data files must be kept in mind. For instance, a bias inreporting rates could exist because (1) registrants were more aware of their TCE exposure, (2)had been advised of the potential effect on their health, and/or (3) might have sought medicalcare more often than the general population. To moderate this potential bias, TCE Subregistrydata were collected with the restriction that a health care provider had to have either told theregistrant they had, or treated them for, the condition. Statistically significant deficits for theTCE population were found for the following health conditions:
- hearing impairment (after age 25 years);
- asthma, emphysema, or chronic bronchitis;
- arthritis, rheumatism, or other joint disorders; and
- other respiratory allergies or problems, such as hay fever.
However, these conditions are often self-diagnosed and medical care is not always sought forthem. Consequently, reporting rates would be affected by the restriction requiring confirmationby a health care provider, and this is reflected in the results.
It is noteworthy that some questions in the two data-collection instruments used for this analysiswere worded differently, making direct comparisons of the reported rates more difficult tointerpret. Also, there is a possibility that, given the large number of comparisons used in theanalyses, there might be some false positive findings. These limitations and restrictions arediscussed further in this report.
In the original Baseline report (2), the environmental data collected were explored for potentialdose-response relationships. The limited environmental data available (usually, the results of oneor two well water sample tests) dictates that the results of these analyses be interpreted withcaution. (Note: In order to further explore the environmental levels of exposure experienced bythe registrants, ATSDR used the historical data in a modeling project; unfortunately this projectdid not produce new insights useful for dose-response calculations.) The most striking findingfrom the limited statistical analyses carried out was the significant elevation in stroke risk withincreased maximum TCE exposure levels. The results also suggested other associations, such asrespiratory diseases with cumulative exposure to TCE and other chemicals, and hearing problemswith length of exposure. It should be noted that the outcomes stroke and hearing impairmentwere also significantly higher in the morbidity outcome comparisons with NHIS.
Although the findings of this report do not identify a causal relationship between TCE exposureand adverse health effects, they do reinforce the need to continue ongoing followup of registrants. ATSDR is investigating two health outcomes (diabetes and anemia) identified previouslyas needing further study. Additional information will be collected for TCE registrants whorespond positively to questions about these two conditions. The NER questionnaires have beenaltered to more closely align the questions with the appropriate questions in the NHISquestionnaire.
Another goal of the National Exposure Registry is to inform registrants of all current informationrelated to their exposures. A TCE Registrant Report, written for the general public andsummarizing the findings of this technical report, was mailed to each registrant in June 1999. ATSDR conducted public availability sessions at each site in June 1999 to discuss the findings described in this report.
ATSDR received the following comments (some portions are excerpted) on the public release version of the Lockwood Public Health Assessment. ATSDR's response to each comment follows.
- Comment: It is crucial that questions and concerns regarding the effects of thiscontamination to children specifically be addressed in this assessment. Specifically, adiscussion of the effects (or possible effects) to children must be included in the"Discussion of Public Health Significance of Contaminants" section for each chemicaldiscussed.
- Comment: For example, an important study on TCE entitled "Human Variability andSusceptibility to Trichloroethylene", (Pastino, G, Yap, W . and Carroquino, MEnvironmental Health Perspectives, Volume 108, Supplement 2, May 2000) specificallydiscusses factors that may affect risk of exposure to TCE in children. Where scientificdata is lacking on specific effects to children, a specific statement on uncertainty of datashould be included for each chemical.
- Comment: An analysis of child health exposure to contaminated well water (e.g.exposure from showering) must also be included in the final draft. This kind of analysis iscommon in many other ATSDR documents. For example, child health exposurecalculations were done by ATSDR for a Health Consultation for Old Payson DryCleaners site in Payson, Arizona available online at: http://www.atsdr.cdc.gov/hac/pha/payson/pay_toc.html. At this site, private well water was contaminated with PCE at amaximum level of 16 ppb (118 times lower than the maximum levels found inLockwood) and the ATSDR did a full analysis of inhalation exposure developing dailyexposure doses and MRLs for both 16 kg children and 70 kg adults. ATSDR alsocalculated both child and adult health exposures to PCE and TCE in a HealthConsultation regarding contaminated groundwater at West Site Hows Corner inPlymouth, ME. This document is available online athttp://www.atsdr.cdc.gov/HAC/PHA/hows/how_toc.html. The current draft PHA forLockwood only analyses exposures for adults. An analysis of children's exposures mustbe included in the final Lockwood Health assessment, so that residents can be informedof the potential chronic health effects to the children they raised in Lockwood.
- Comment: In addition, the discussion on page 33, regarding the impacts to childrenswimming in pools filled with well water must be expanded. The brief discussion is quitevague and does not answer the question. The answer should include an analysis ofchildren's exposure at the maximum contaminant levels found in Lockwood, similar tothe shower analysis that was done for adults. This analysis should clearly state howexposure to pool water may have impacted the children's health, and what those healtheffects might be. This is a valid concern of the residents of Lockwood and deserves to beresponded to appropriately.
- Comment: This public health assessment is completely lacking information on theeffects of these chemicals on pregnant women and a developing fetus. The ATSDR factsheet on tetrachloroethylene states "[women exposed to high levels of PCE] may havemore menstrual problems and spontaneous abortions than women who are not exposed."The ATSDR fact sheet (September 1997) on trichloroethylene clearly states that"drinking small amounts of trichloroethylene for long periods may cause… impaired fetaldevelopment in pregnant women." The ATSDR fact sheet on vinyl chloride (September1997) states that "animal studies have shown that breathing vinyl chloride can harmunborn offspring and may also cause increases in early miscarriages." However, none ofthese effects are currently mentioned in this health assessment.
ATSDR Response: Throughout the health discussions in the public health assessmentconcerning the possibility of harmful effects, ATSDR refers to residents. The termresidents includes both adults and children. ATSDR has made it more clear in the textthat residents refers to both groups.
To determine if harmful effects might occur in Lockwood residents who were exposed toVOCs, ATSDR estimated exposure levels for each VOC and compared those estimatedexposure levels to health guidelines (i.e., MRLs and RfDs) and when appropriate toexposure levels in human and animal studies. If the estimated dose in Lockwood residentsis below the MRL or RfD, no further evaluation is necessary for either adults or childrento determine if non-cancerous harmful effects are possible. The text in the PHA presentsthe findings for the contaminants of concerns found in private wells in Lockwood. Whenan MRL or RfD is exceeded or when one does not exist, ATSDR compared estimateddoses in Lockwood residents to the lowest level in human or animal studies that wereknown to cause harmful effects and reported the comparison as a margin of safety(MOS). For instance if the estimated exposure level is 10 ppb and the animal exposurelevel is 1000 ppb, the margin of safety is 100 (i.e., 1000/10). The MOS of safety wasreported for adults in the PHA.
In response to the comment about evaluating children, ATSDR has revised the text toalso reflect the margin of safety for children. In every case, the margin of safety wasgreater for children. For instance, if the MOS for adults was 100 then the MOS forchildren was 120. Explained another way, if the estimated exposure level in Lockwoodadults was 100 times lower than the level known to cause harmful effects, the estimatedexposure level in Lockwood children who used the same private well was120 timeslower. Tables 9 and 10 now reflect the exposure level for adults and children.
It is important to realize, however, that if the MRL or RfD is not exceeded or if themargin of safety is too large, then ATSDR does not describe harmful effects. Therefore,there will be times when ATSDR does not describe harmful effects in children becausesuch a description is not warranted when the exposure level is too low.
ATSDR Response: ATSDR reviewed this study while conducting its evaluation of VOCexposures in Lockwood residents. ATSDR also sent a copy of the study to the lawyerhired by the residents so that he would have the latest information available.
It is important to realize that an ATSDR public health assessment does not present areview of the toxicological literature on a particular chemical; therefore, ATSDRdescribes possible harmful effects only if the doses (or exposure levels) are high enoughto potentially cause harmful effects. For the acute exposures that occurred while taking ashower, the estimated TCE exposure levels in children who used the most contaminatedprivate well was 242 ppb. Since 242 ppb is below ATSDR's acute MRL of 2,000 ppb,harmful effects are not likely. Therefore, it is not necessary to pursue further to determineif children are more sensitive to TCE for acute exposure because ATSDR's acute MRLalready accounts for their potentially increased sensitivity. For intermediate and chronicexposures, ATSDR estimated that daily children were exposed to 16 ppb TCE. Thisexposure level (16 ppb) is below ATSDR intermediate MRL of 100 ppb; therefore, it isnot necessary to evaluate whether children are more sensitive because ATSDR'sintermediate MRL already protects against that possibility.
However, neither ATSDR nor EPA have established health guidelines for chronicexposure to TCE in air. Therefore, in preparing the public release version of the PHA,ATSDR conducted further toxicological evaluations, directly comparing the estimatedchronic exposure level of 16 ppb to known animal studies. The conclusion of thatcomparison is that harmful effects are not likely since the estimated exposure level isabout 17,000 times lower than the level known to cause harmful effects in rodents. Thediscussion in the PHA, however, points out that some uncertainty exists in this conclusionbecause of the limited number of studies. Even though children in general might be moresensitive to the effects of TCE, it is not possible to determine if children in Lockwoodexposed to 16 ppb would experience harmful effects, again because of the limited numberof studies.
To ensure that nothing was missed when considering children, ATSDR reviewed thePastino article again to determine if any text should be added to the PHA.
ATSDR Response: ATSDR did estimate exposure doses in both adults and children,although only adult values were included in the PHA because they were higher than theestimated values for children. The approach used in the Payson health consultationconsisted of estimating acute and chronic doses from a shower, estimating a dermal dose,and estimating a combined acute and chronic dose from both routes. The same generalapproach was used to estimate acute and chronic doses for Lockwood residents. To makeit clear that ATSDR estimated doses in children, the appropriate tables in the PHA nowinclude the estimated exposure levels for adults and children. It should be noted that thePayson health consultation concluded that 16 ppb PCE was not a risk to children fromtaking a shower even considering that they might possibly be more sensitive. TheLockwood public health assessment concluded that harmful effects might occur in someresidents (i.e., adults and children) because the exposure levels at Lockwood were muchhigher at a few residences.
ATSDR Response: The question being posed to ATSDR on page 33 (#6) is whether ornot VOCs in kiddie pools can harm residents' health and ATSDR answers this questionin its response. ATSDR agrees that the explanation for this answer can be improved sothat it is more clear specifically what chemicals are a problem. ATSDR used the conceptthat if it was not safe to bath or shower in private well water then it would not be safe touse private well water for kiddie pools.
We found it rather surprising, given the consistency with which it is mentioned in othersimilarly contaminated sites ATSDR has evaluated, that the Lockwood PHA wouldcompletely omit an analysis of effects to pregnant women and fetuses. We highlyrecommend that ATSDR review these other ATSDR reports and apply the knowledge tothe PHA for Lockwood. An analysis and discussion of the effects on pregnant women andfetuses at Lockwood must be included in the final PHA.
Many studies have detected perchloroethylene, trichloroethylene, 1,2 dichloroethane andcarbon tetrachloride in breast milk. Therefore, transfer of solvents through breast milk isan important exposure pathway which must be discussed in this assessment. Whileorganic solvents can be relatively short-lived in the body, they can build up in breast milk,especially in women who are exposed daily. Nursing mothers in Lockwood who wereexposed daily to high PCE levels from their groundwater, are likely to have hadmeasurable levels of solvents in their breast milk. Studies have been conducted toestimate levels of solvents transmitted to breast feeding infants. In one study, a simulatedexposure of a lactating woman to a threshold limit value of perchloroethylene resulted inan ingestion rate that exceeded drinking water standards for children. (Fisher, J., et al.Lactational Transfer of Volatile Chemicals in Breast Milk, American Industrial HygieneAssociation Journal 1997; 58: p. 425-431.) Other examples of studies on this issue are:
- Schreiber, J.S. Predicted Infant Exposure to Tetrachloroethene in HumanBreastmilk, Risk Analysis 1993; 13(5): p. 515-524.
- Pellizzari, E.D., et al. Purgeable Organic Compounds in Mother's Milk, Bulletinof Environmental Contamination and Toxicology 1982; 28: p. 322-328.
- Byczkowski, J.Z., J.M. Gearhart, and J.W. Fisher. "Occupational" Exposure ofInfants to Toxic Chemicals via Breast Milk, Nutrition 1994; 10(1): p. 43-48.
- Giroux, D., G. Lapointe, and M. Baril. Toxicological Index and the Presence inthe Workplace of Chemical Hazards for Workers who Breast-feed Infants,American Industrial Hygiene Association Journal 1992; 53(7): p. 471-474.
In addition the Health Consultation for Natick Laboratory Army Research in Natick, MA found that "PCE has a high affinity for fat and has been found at elevated levels in thebreast milk in women living near dry-cleaning facilities where exposure to PCE occurreddaily." This document references several journal articles on this subject which can beaccessed at: http://www.atsdr.cdc.gov/HAC/PHA/natick/nla_p2.html.
The breast milk exposure pathway for the contaminants of concern in Lockwood must bediscussed in the final Public Health Assessment.
ATSDR Response: It is important to realize that the decision to mention or not mentionknown toxic effects of a chemical is first based on whether or not someone who waspregnant showered in contaminated water. While interviewing residents about theirquestions and health concerns about contaminated groundwater and private wells, none ofthe residents had questions about the harmful effects during pregnancies. In addition, theresidents who had private wells with significant VOC contamination were well past theirchild bearing years. To ATSDR's knowledge, none of the residents who used privatewells with VOCs above drinking water standards were exposed during pregnancy;therefore, harmful effects to the fetus or to an infant from breast feeding is not possible.
ATSDR Response: When exposures are high enough, the public health assessment willdescribe the health effects that might occur in exposed people. When exposures do notexceed a health guideline (e.g., a MRL or RfD) or when exposure levels are too low, adescription of the known toxic effects of a chemical is not given. As mentioned in thecomment, the estimated levels of TCE exposure are below the acute, inhalation MRL;therefore, a description of toxic effects is not warranted. ATSDR reviewed the descriptionof toxic effects for other chemicals in the report and could find no cases where adescription of toxic effects were given when the estimated exposure levels were below anMRL
The confusion may have resulted from ATSDR not including the acute MRL for PCE inthe discussion. This oversight has been corrected. Also in response to the commentATSDR made revisions in the Public Health Implications section so it would be clear tothe reader when ATSDR described possible health effects residents.
ATSDR Response: ATSDR agrees and the citation is now in the public healthassessment.
There is also a wealth of data available from the results from the ATSDR'sTrichloroethylene subregistry. These results should also be discussed in detail in thechronic health effects section - indicating the greater frequency of rashes, speechimpairment, hearing impairment, stroke, anemia, diabetes, kidney disease and urinarytract disorders in populations exposed to TCE. Even though this information is includedlater in the document, there is no harm in being repetitive as the average reader of thisdocument is unlikely to read every word. To be clear, all chronic health effects associatedwith TCE should be easily found in the section clearly titled "TCE: Chronic Exposure". It is not helpful to have to hunt to find this information piecemeal in different placesthroughout the document.
The "TCE: Chronic Exposure" section clearly needs to be expanded significantly toreflect the wealth of scientific information which does in fact exist.
ATSDR Response: What makes an ATSDR public health assessments unique is that itavoids reciting the known toxic effects of a chemical. Instead, ATSDR estimates a site-specific doses and uses those estimates to decide whether or not harmful effects arepossible. When harmful effects are possible, the public health assessment describes theharmful effects that might occur in the exposed population. When harmful effects are notlikely, the report will contain that conclusion but not go into a list of known harmfuleffects for a chemical. For Lockwood, ATSDR estimated the exposure level (i.e., dose)for residents of each household that had a contaminated well and used those estimates todecide if harmful effects might occur.
In the case of TCE, both the acute and chronic estimated exposure levels were too low tocause harmful effects. Because harmful effects from TCE were not likely in Lockwoodresidents, the PHA did not describe any of the known toxic effects.
As for ATSDR's report on the TCE subregistry, at this point, the conclusions from thesubregistry cannot be used to determine if TCE caused the signs, symptoms, and diseasesdescribed in the TCE subregistry report. This is probably the first time that ATSDRincluded the TCE subregistry report in a public health assessment. The purpose ofproviding the report was so that residents could have the latest information that ATSDRhas available.
Currently the Lockwood PHA only mentions an increased cancer risk due to PCEexposure. Given that maximum levels of TCE in Moses Lake were five times lower thanlevels found in Lockwood, the additional cancer risk from TCE must be stated anddiscussed in the final PHA.
Another site which mentions cancer risk from TCE exposure is the preliminary PublicHealth Assessment for the Dublin Water Supply in Dublin, PA. This PHA stated that "Long-term exposure to TCE at levels found in water supplies may pose a significantincrease in the risk of developing cancer." At the Dublin site, maximum TCE levels were4,450 ppb which is higher than the levels found in residential wells, but comparable tomaximum levels found in Lockwood groundwater monitoring wells. The Dublin PHAcan be accessed at: http://www.atsdr.cdc.gov/HAC/PHA/dublin/dub_p2.html.
ATSDR Response: ATSDR agrees and a discussion of TCE carcinogenicity has beenadded to the TCE subsection.
ATSDR Response: The McCauley article was considered in ATSDR's evaluation ofDCE exposure in Lockwood residents. The McCauley study is included in ATSDR'sToxicological Profile for 1,2-Dichloroethene and is listed in Table 2-2 as study #3. Theconfusion comes from the McCauley study being published more than one time. It waspublished in a scientific journal in 1995 but had previously been published in 1990 as partof an EPA and Air Force document.
It is also important to consider the route of exposure when deciding whether or not to usea study to decide possible health effects. In the case of exposure during showers, theroute of exposure is from breathing DCE that has evaporated to the air. The other routeof exposure is absorption through the skin. As explained earlier in this report, skinabsorption is more closely related to inhalation than to ingestion because the distributionpattern after skin absorption is more similar to the distribution pattern after inhalation. The route of exposure for rats in the McCauley study is by mouth, that is, ingestion. Because of possible differences in how a chemical is metabolized when exposure is bymouth versus exposure via the lungs, and because Lockwood residents were exposed viainhalation, it is more appropriate to use studies where exposure was by inhalation.
The Preliminary Public Health Assessment for the Dublin Water Supply in DublinPennsylvania, makes a similar statement: "Certain populations that may be especiallysensitive to TCE exposure include chronic consumers of alcohol and persons with heartdisease. Persons taking disulfiram, a medication used for the treatment of alcoholism,may also be at an increased health risk through TCE exposure."(http://www.atsdr.cdc.gov/HAC/PHA/dublin/dub_p2.html#Toxicological)
The Public Health Assessment for Rowe Industries Groundwater Contamination in SagHarbor, NY also discusses these sensitive populations with slightly more detail: "Since very high level exposures (much higher than those that occurred in Sag Harbor -100 to 1,000 times higher) to VOCs are known to cause liver, kidney, and heart damage,people with clinical or subclinical liver and kidney disease may be more sensitive to theeffects of VOCs. In addition, people who abuse alcohol or who are treated withdisulfiram may be at greater risk of VOC adverse health effects because both inhibit thebody from eliminating the VOCs and can cause the VOCs to accumulate in thebloodstream." (http://www.atsdr.cdc.gov/HAC/PHA/row/rig_p2.html#A.Simultaneous)
ATSDR Response: ATSDR agrees and a subsection about sensitive groups is now partof the public health assessment.
ATSDR Response: As suggested, the document has been revised to include the levels ofcontamination detected in groundwater and the appropriate comparison values withinproximity to one another. Several tables have been added for easy reference.
ATSDR Response: As suggested, the document has been revised to include anappropriate mathematical reference to indicate the extent of exceedence of the detectedgroundwater concentration when compared to the comparison value. The revised text iscontained in the section entitled "Completed Exposure Pathways".
ATSDR Response: The highest concentration for TCE in groundwater detected by a fieldinstrument (gas chromatograph (GC)) is 3,770 ppb; the highest concentration of cis-1,2-DCE in groundwater detected by a field instrument is 15,200 ppb. The highestconcentration of TCE in groundwater detected by a laboratory is 3,200 ppb; the highestconcentration of cis-1,2-DCE detected in groundwater by a laboratory is, 11,000 ppb.Initially, ATSDR had decided to use in its assessment only groundwater samples that hadbeen analyzed in a laboratory. In general, results from laboratory-analyzed samples aremore reliable than results determined by field GC. Upon further evaluation, ATSDRdetermined that there was good correlation between the laboratory-analyzed samplingresults and the field GC-analyzed sampling results. Therefore, we decided it wasacceptable to include field GC sampling results in our evaluation. The levels reported inAppendix B were revised to reflect this change of opinion. However, the text on page 7was not revised accordingly. The text has now been revised to show the highestgroundwater levels from either laboratory-analyzed samples or field GC samples.
ATSDR Response: As suggested, the document has been revised so that the maximumindoor air concentrations and the air comparison values are in the same paragraph. Achart has been added for easy reference. The maximum indoor air levels are compared tothe average background indoor air levels for U.S. homes in Tables 7 and 8 in AppendixB.
ATSDR Response: The statement on page 8 refers to the indoor air sampling conductedbetween September 1999 and May 2001. The reader is referred to Table 3 in Appendix Bfor a list of those contaminants in air which exceeded an applicable comparison value.Specifically, Table 3 reveals that methylene chloride, chloroform, carbon tetrachloride,bromodichloromethane, vinyl chloride, 1,1-dichloroethene, and 1,2-dichloroethaneexceed their comparison values. (PCE, TCE, and cis-1,2-DCE are included in Table 3 forillustrative purposes even though these chemicals did not exceed their comparisonvalues.) The statement on page 11 refers to a specific discussion about the homes over thehighest levels of groundwater contamination and the presence of the major contaminantsof concern - PCE, TCE, cis-1,2-DCE, and vinyl chloride. The two homes over the highestgroundwater contamination did have higher level of these VOCs in their indoor air whencompared to other homes in the area; however, the concentration of the VOCs, althoughhigher, did not exceed applicable comparison values. The text has been revised to clarifythese two seemingly contradictory statements.
Clearly there are other contaminated homes in the U.S., perhaps even more contaminatedthan those in Lockwood, so the "range that one finds in indoor air of U.S. homes" isprobably quite large. Stating that the levels found in Lockwood fall within that rangewhile true, is entirely misleading. Naturally, the levels found in Lockwood are within theuniverse of possible values found in U.S. homes but that is merely stating the obvious andis entirely irrelevant. The fact is that levels in Lockwood have been detected at levels 20-40 times higher than average levels found in U.S. homes, which is the relevantcomparison and should be the only comparison stated here. Furthermore, there is nocitation listed for the claim that "19 ppb of PCE is not uncommon for someone whobrings dry cleaning home." - other than "conversations with Dr. Lance Wallace." If Dr.Wallace has published data which clearly state that homes containing dry cleaned clotheshave shown average levels of 19 ppb - those studies should be cited. If not, this claimshould be omitted.
ATSDR Response: ATSDR has revised the discussion about indoor air levels andcomparison to background indoor air levels from national studies in order to correct anyconfusing or misleading statements. It is important to explain, when possible, why indoorair levels of VOCs might be elevated so that residents can understand the issuesconcerning the interpretation of indoor air levels. Therefore, several statements that thecommenter objected to remain in the public health assessment. ATSDR, however,attempted to explain and document these statements better.
ATSDR Response: This public health assessment has been updated to include indoor airsampling conducted through February 2002.
ATSDR Response: ATSDR has consulted with the Montana DEQ regarding the sourceof potable water for residents in the aforementioned homes and trailer park. We wereinformed that public water supply lines are available to residents in these homes; mostresidents are believed to receive their water from the public water supply. Additionally,the level of contamination detected in proximity to these residences has not exceededstate or federal drinking water standards to date. Further information about the extent ofgroundwater contamination will be revealed as DEQ continues their RemedialInvestigation. ATSDR will continue to evaluate any additional information as it becomesavailable.
We believe the Lockwood community deserve to see the same respect, concern and hardwork put into their Public Health Assessment as the many other communities mentionedabove (i.e., Rowe Industries Groundwater Contamination, Old Southington Landfill)received from ATSDR. The people of Lockwood are very concerned about their healthand the potential impacts from their contaminated groundwater.
ATSDR Response: Part of ATSDR's initial activities at the Lockwood Solvents Siteinvolved requesting input from residents in the community about how the contaminationaffected their lives. The letters submitted to ATSDR by residents were evaluated byATSDR staff to determine the need for future stress management activities at the site.ATSDR staff were available at the public availability sessions held in Billings in March2002 to discuss stress management issues with residents and to provide individualreferrals to appropriate mental health personnel, as necessary. ATSDR is also available toprovide stress management training and a list of local mental health resources at any timeif requested by the community.