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PUBLIC HEALTH ASSESSMENT

Evaluation of Exposures in Areas Associated with PAH Contamination

GARDNER-ROUSSEL PARK and DR. NORMAN W. CRISP ELEMENTARY SCHOOL
(a/k/a DR. CRISP SCHOOL/GARDNER ROUSSELL PARK)
NASHUA, HILLSBOROUGH COUNTY, NEW HAMPSHIRE


SUMMARY

The Gardner-Roussel Park/Dr. Norman W. Crisp Elementary School site is located onArlington Road in Nashua. Gardner-Roussel Park is a public park with recreationalfacilities, and is abutted by the Dr. Norman W. Crisp Elementary School. The site isbordered on all sides by residential neighborhoods.

In November 2001, the Nashua Department of Public Works found polycyclic aromatichydrocarbons (PAHs) in the soil while preparing to renovate the park. They contactedthe New Hampshire Department of Health and Human Services (DHHS) to furtherinvestigate the potential for exposure to PAHs in the park. DHHS completed this PublicHealth Assessment under its cooperative agreement with ATSDR.

What kind of chemical contamination was found on the site?

PAHs are the major contaminants of concern at the site and exist at very low levels insurface soils in the park and near the school. DHHS evaluated the likelihood thatexposure to these contaminants at the site could cause cancer and found that there was nosignificant cancer risk. Not only does the landfill upon which the park was built containthe waste from small-scale incineration, but it also contains the remains of a large firethat took place in Nashua in the 1920s. There is insufficient information to determinewhether or not waste coal ash from the furnaces were dumped in this landfill.

Soil testing by an environmental consulting firm showed that the soil on the site (the parkand the grounds around the school) contained PAHs. Many areas that were sampled andanalyzed, contained levels of PAHs that were similar to levels found in urban soils [6]. One area of a slope in the northwest corner of the park had levels of PAHs several timeshigher than the surrounding areas.

What health effects might result from exposure to chemical contamination at the site?

None of the current exposures at the site is expected to cause adverse health effects. Therefore, DHHS has categorized current conditions at this site as No Apparent PublicHealth Hazard according to ATSDR's hazard classification system. Site remediation hasalready been accomplished. In the future, contamination at the site will be less than whatis characterized in this Public Health Assessment.

Could current or past exposures to chemical contamination at the site have caused anincreased rate of cancer in the community?

Current or past exposures to cancer-causing chemicals on the site (e.g., PAHs) are notexpected to result in increased cancer risk. Due to community concerns about cancer,DHHS obtained data from the New Hampshire State Cancer Registry and performed astandardized mortality ratio analysis on all cancer types for the ZIP code including theGardner-Roussel Park, the Dr. Crisp Elementary School and the surroundingneighborhoods. This analysis found more male cases of esophageal cancer and testicularcancer then we would have expected to see. It is unlikely that the elevated number ofcases of cancer is due to chemicals found on the site. PAHs are not known to beassociated with esophageal cancer or testicular cancer. In addition, the exposures to lowlevels of PAHs on the site are at a level unlikely to cause adverse health effects.

Is the site being cleaned up?

Yes. The testing for PAHs resulted from a citywide effort to remediate parks in Nashua. As a result of the discovery of the "hot spot", an area with PAHs several times higherthan the surrounding areas, on the slope of the northwestern area of the park, the city ofNashua covered this area with 12 inches of clean fill. As well as covering this "hot spot",the Nashua Department of Public Works plans to give the park a thorough renovation.

Where can I get more information?

The text and appendices of the Public Health Assessment contain more information about the health issues discussed in this summary. To ask questions about this Public Health Assessment or to obtain extra copies of this document, please contact Dennis Pinski in the DHHS Bureau of Health Risk Assessment at (603) 271-4664 or (800) 852-3345 ext. 4664 (toll-free in New Hampshire). You can also send an email to the Bureau at healthrisk@dhhs.state.nh.us or visit our website at http://www.dhhs.state.nh.us/dhhs/hlthriskassess/default.htm where the report is available online. Additional copies of this Public Health assessment will be available at the Reference Desk at the Nashua Public Library at 2 Court Street, Nashua, NH 03060 [(603) 594-3412].

If you would like more information on the renovation of the park and the conditions ofthe Dr. Norman W. Crisp Elementary School, please contact the Nashua Department ofPublic Works at (603) 589-3140.


I. PURPOSE

In November 2001, the City of Nashua contacted the New Hampshire Department ofHealth and Human Services (DHHS) due to the detection of chemicals in the soil ofGardner-Roussel Park. The City asked DHHS' assistance to determine whether exposureto these chemical contaminants posed a health risk either to users of the park oroccupants of the Dr. Norman W. Crisp Elementary School.

On July 8th, 2002, DHHS completed a health consultation reviewing the public healthimplications of environmental data from the park. Since there was considerable publicinterest, as well as a large number of community health concerns regarding Gardner-Roussel Park and the Dr. Norman W. Crisp Elementary School, DHHS decided that themost appropriate way to address these concerns was to perform a public healthassessment for this site. A public health assessment is a tool used to determine if anyactions are needed to protect the community surrounding a hazardous waste site, and todetermine if follow-up health activities (e.g., health studies or medical surveillance)should be done. To achieve this goal, this assessment contains three types of evaluations:(1) identification of pathways of exposure to site contaminants and an evaluation of theirpublic health implications; (2) a summary of relevant and available health outcome data(i.e., cancer registry data); and (3) an evaluation of specific community health concernsabout the site.

DHHS completed this Public Health Assessment under its cooperative agreement withthe U.S. Agency for Toxic Substances and Disease Registry (ATSDR).


II. BACKGROUND AND STATEMENT OF ISSUES

Site Description and History

Gardner-Roussel Park is adjacent to the Dr. Norman W. Crisp Elementary School,located on Arlington Road in Nashua. Elevated levels of polycyclic aromatichydrocarbons (PAHs) on this site were discovered in mid-November 2001, while the Cityof Nashua was preparing to renovate the existing facilities in the park. There are severalpossible sources of contamination. The park was built in the 1950s over an unregulatedlandfill, where small-scale incineration took place [1]. The landfill site supposedlycontained the remains of a large fire in Nashua [1]. The landfill is also thought to containcoal ash from small utility boilers [1]. The source of the fill used to cover the waste pit isunknown [1].

Three samples taken from the park indicated levels of PAHs that were above NewHampshire Department of Environmental Services (DES) screening standards. As aprecautionary measure, the park was closed, fenced off and entrance restrictions wereposted. These restrictions were in place until a private environmental consulting firmrepresenting the City characterized the areas of the park that were most in need ofremediation. The sampled areas that were above DES screening levels were coveredwith clean fill [1]. As an additional precaution, additional tests to detect PAHs wereconducted in and around the Dr. Crisp School. Nine soil samples from the schoolgrounds were tested. The "hot spot" in Gardner-Roussel Park, or the area with thehighest PAH concentrations, was resampled to test for dioxin. Air inside the school wasmonitored for airborne PAHs. As an additional measure, the City of Nashua askedDHHS to determine whether the present levels of PAHs from soils in the park, on theschool grounds and in the school were a public health hazard.

The "site" evaluated in this Public Health Assessment focuses on three main areas: (1) Gardner-RousselPark; (2) the grounds surrounding the Dr. Norman W. Crisp Elementary School (the school and its groundsare adjacent to Gardner-Roussel Park); and (3) the indoor environment of the Dr. Crisp School.

Demographics

Nashua is the second largest city in New Hampshire. According to the U.S. Census, thepopulation of Nashua in 2000 was 86,605 persons. Children less than 5 years old andadults over 65 years old accounted for 18% of the population. The age distribution forthe population is summarized in the following table [2].

Age (years) Persons Percentage
Less than 5

5,644

6.5

5 to 17

15,710

18.1

18 to 64

55,209

63.8

65 to 84

8,807

10.2

85 and greater

1,235

1.4

Total

86,605

100.0

Site Visit

In November and December 2001, representatives of DHHS' Bureau of Health Risk Assessment (BHRA)visited the site to observe current conditions and land use around the site.

Gardner-Roussel Park was fenced off in November 2001 until further tests were completed and clean fillwas applied to cover areas of concern. Most of the park was on a uniform surface with consistent grasscover. In the northwest section of the park, there was a short, steep hill leading to the Dr. Crisp Schoolgrounds. This slope is where the highest concentrations of PAHs were found in the surface soil. There didnot appear to be any bare soil or holes that could expose subsoil.

The grounds around the Dr. Crisp School consisted of several separate areas. The areas around theperimeter of the building were on flat, landscaped surfaces with grass cover. There were two separateplayground areas; both areas were covered with a deep layer of bark chips. There did not appear to be any bare soil or holes that could expose subsoil.


III. DISCUSSION

Assessment Methodology

To determine whether nearby residents are exposed to contaminants from the site,ATSDR and DHHS evaluated the environmental and human components that lead tohuman exposure. This pathways analysis consists of five elements: (1)a source ofcontamination; (2) transport of contaminants through an environmental medium;(3) apoint of human exposure; (4) a route of human exposure; and, (5) a receptorpopulation.ATSDR classifies exposure pathways into three groups: (1) completedpathways; i.e., those in which exposure is reasonably likely to have occurred, to occur,or to occur in the future; (2) potential pathways; i.e., those in which exposure mighthave occurred, may be occurring, or may yet occur; and, (3) eliminated pathways; i.e.,those that can be eliminated from further analysis because one of the five elements ismissing and will never be present, or in which no contaminants of concern can beidentified.

After the pathways are designated as completed, potential, or eliminated, ATSDR usuallyfollows a two-step methodology to comment on public health issues related to exposurepathways at hazardous waste sites. First, ATSDR obtains representative environmentalmonitoring data for the site of concern and compiles a list of site-related contaminants. ATSDR compares this list of contaminants to health-based comparison values (HCVs) toidentify those contaminants that do not have a realistic possibility of causing adversehealth effects. These comparison values are conservative, because they include amplesafety factors that account for the most sensitive populations. ATSDR typically usesHCVs as follows: if a contaminant is never found at levels greater than its comparisonvalue, ATSDR concludes the levels of corresponding contamination are not at levels ofpublic health concern. If, however, a contaminant is found at levels greater than itsHCV, ATSDR designates the pollutant as a contaminant of concern and examines itfurther in the assessment. Because HCVs are based on conservative assumptions, thepresence of concentrations greater than a HCV does not necessarily suggest that adversehealth effects will occur among the exposed population. More information on thecomparison values can be found in Appendix F.

For the remaining contaminants, ATSDR evaluates site-specific conditions to determinewhat exposure scenario is realistic for a given exposure pathway. Given this exposurescenario, ATSDR determines a dose and compares this dose to scientific studies todetermine whether the extent of exposure indicates a public health hazard.

Environmental Sampling

PAHs in Soil

PAHs were initially discovered in a subsurface (1-3.5 feet) sample [3]. The levelsexceeded state standards. As a result, a surface soil sampling program was conductedusing a 100-foot grid across the park. Thirty surface soil samples were collected inNovember 2001 and analyzed for PAHs. All soil samples are reported in parts permillion (ppm). The compounds reported included the non-carcinogenic PAHs(naphthalene, 2-methylnaphthalene, acenaphthene, fluorene, phenanthrene, anthracene,fluoranthene, pyrene, benzo[g,h,i]perylene and acenaphthylene) and the carcinogenicPAHs, (benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene,benzo[k]fluoranthene, chrysene, dibenzo[a,h]anthracene and indeno[1,2,3-c,d]pyrene). Ifa sample contained concentrations of any one non-carcinogenic PAH above the HCV, orcontained benzo[a]pyrene (BaP) above its sample quantitation limit (SQL), the samplewas further evaluated. The SQL is the lowest concentration that the analytical equipmentor procedure can detect. If necessary, a dose was estimated. The Exposure PointConcentrations (EPCs) used in calculating doses of carcinogenic polycyclic aromatichydrocarbons (cPAHs) were expressed as Benzo[a]pyrene Toxic Equivalencies (BaP-TEs), which is based on the potency of each cPAH relative to that of BaP, since this isconsidered to be the most potent cPAH [4]. Each cPAH is assigned an equivalencyvalue. The TE values are then summed.

Surface soil samples in which all cPAHs are below the detection limit are not included in the followingtables. In Gardner-Roussel Park, 9 out of 30 samples had PAHs above the detection limit: RH-100, RH-102, RH-103, RH-105, RH-106, RH-107, RH-123, RH-125 and RH-127. In these samples, all non-carcinogenic PAHs in all samples were below their respective HCVs (Table 1). Three soil samples fromthe non-remediated areas had levels of BaP above the detection limit: RH-102, RH-103, and RH-127 (Table 1).

Four sampling areas in the park were covered with clean soil: RH-100, RH-105, RH-106 and RH-107. These samples were considered separately from sampled areas not covered because an exposure (in thisarea) could have only occurred in the past, whereas other areas represent present and future exposures. Ofthese covered samples, all non-carcinogenic PAHs in all samples were below their respective comparisonvalues (Table 2). All of these samples had levels of BaP above the detection limit and above the Environmental Media Evaluation Guide (EMEG, a media-specific comparison value usedto select chemicals of concern).

On the school grounds, all non-carcinogenic PAHs in all surface soil samples were below their respectiveHCVs . Five soil samples had levels of BaP above the detection limit and above the HCV: DC-1, DC-5, DC-6, DC-7 and DC-9 (Table 3).

As stated above, the Exposure Point Concentrations (EPCs) of the cPAHs were calculated when a samplecontained levels of any one cPAH above the Sample Quantitation Limit (SQL). If every cPAH wasreported below the SQL, it was assumed that cPAHs were not present in that sample. Also, severalsamples had cPAHs above and below the SQL. In this scenario, those below the SQL were assigned aproxy concentration of one-half the SQL (in this case, the SQL was always 0.33 ppm). This is consistentwith U.S. Environmental Protection Agency (EPA) guidance, which recognizes that quantitation limits canlead to unrealistic concentration estimates [4, 5]. Cumulative cPAH concentrations were expressed asBaP-TEs. Calculating a BaP-TE requires converting each cPAH into an equivalent amount of BaP, basedon its relative carcinogenic potency [4]. The BaP-TEs were then added, for each sample and eachcompound. Tables 4, 5 and 6 show actual cPAH concentrations for all samples at Gardner-Roussel Parkand the Dr. Crisp School grounds, as well as their corresponding BaP-TEs.

These overall (average) levels of PAHs are similar to levels typically found in urbansoils. Many urban soils in New England commonly have levels of PAHs that are higherthan the background levels normally found in a non-urban environment [6].

Dioxin in Soil

Two additional surface soil samples were collected in the same vicinity of RH-100 andRH-105, to determine if dioxin was present at elevated levels on the slope. The resultwas an average total TCDD equivalent concentration of 19 nanograms per kilogram ofsoil (a nanogram is equivalent to one billionth of a gram; expressed as ng/kg) [7]. Thislevel is slightly below the ATSDR EMEG of 20 ng/kg soil (this EMEG reflects childrenwho are chronically exposed); thus, based on ATSDR EMEG, these concentrations arebelow levels at which health effects are likely to occur. Incomplete combustion of fossilfuels is also an environmental source of dioxin. These concentrations of dioxin do notrequire further evaluation and are not considered to be a public health concern.

PAHs in Indoor Air

Due to community concerns about the proximity of Gardner/Roussel Park to the Dr.Crisp Elementary School, the City of Nashua had four separate air samples collectedfrom inside the building and tested for airborne PAHs. Samples were drawn whilestudents were present. The sampling locations were based on the daily movements of agroup of students considered to be representative of the whole student body. Thesampling device followed this group throughout the school day. The results wereexpressed as micrograms of PAHs per cubic meter (g/m3). All indoor air samples werenon-detect for all PAHs except naphthalene, a non-carcinogenic PAH. Naphthalene wasdetected in concentrations between 0.426 and 0.868 g/m3 [7]. These levels are belowATSDR's Air Comparison Value (ACV) of 10.482 g/m3; therefore it is unlikely thatadverse health effects would be expected to occur. This does not require furtherevaluation.

It is likely that the naphthalene is from a common indoor source rather than from parksoil containing PAHs. Naphthalene is commonly found in a variety of sources such asmothballs, toilet deodorant bars, cigarette smoke and combustion of fossil fuel basedheaters (i.e., furnaces or boilers).

Analysis of Exposure Pathways

As previously indicated, there are five factors that constitute a completed exposurepathway. First, there must be a source of contamination. Second, there must be atransport of contamination through an environmental medium, such as soil, air orgroundwater. Next, there must be a point of exposure, which is the soil surface on thesite. Fourth, there must be a route of exposure, which is through dermal absorption andincidental ingestion. Finally, there must be an actual exposed population of people whouse the park. ATSDR and DHHS consider incidental ingestion (eating) and dermalexposure (skin contact with soil) to contaminated surface soil at Gardner/Roussel Park tobe a completed exposure pathway in the past, present and in the future. Since the areaswith the highest levels of chemicals were covered in November 2001, past exposure wasevaluated separately from present and future exposure. As well, the grounds around theDr. Norman W. Crisp Elementary School represent a completed exposure pathway forpast, present and future exposure. Inhalation of airborne PAHs is also considered acompleted exposure pathway since airborne concentrations in the building can betransported from the air to individuals. A completed exposure pathway means that thereis reasonable expectation to believe exposure has occurred, is occurring or will occur atsome future time.

Since the exposure to dioxin in soils and naphthalene in indoor air were below theirrespective HCVs, adverse health effects are not expected. Therefore, only the publichealth implications of exposure to PAH-contaminated soils will be evaluated further.

Public Health Implications of Exposure to PAH-Contaminated Media

cPAHs are the contaminants of concern in Gardner-Roussel Park since theirconcentrations are above the health comparison values. Therefore, the public healthimplications of exposure to PAHs in the contaminated soil will be evaluated below.

PAHs comprise a group of over 100 different chemicals that are formed during theincomplete burning of coal, oil, gas, garbage, and other organic substances as diverse astobacco or charbroiled meat. PAHs are usually found as a mixture containing two ormore of these compounds. Because of the complexity of these mixtures, the most activecompound, benzo[a]pyrene, is used as the indicator compound. People coming intocontact with PAHs in soil do so through incidental ingestion or dermal contact. PAHsingested by mouth have an absorption rate of approximately one-third of the total amountingested. Absorption from the skin to the blood is lower than through the oral route, sodermal exposure is a secondary route of exposure [8]. Airborne PAHs, resulting fromvolatilization of household products or fossil fuel combustion, are inhaled and absorbedby the lungs. While not all PAHs are considered carcinogenic (e.g., naphthalene), theEPA has determined that benz[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene,benzo[k]fluoranthene, chrysene, dibenz[a,h]anthracene, and indeno[1,2,3-c,d]pyrene areprobable human carcinogens [8].

To evaluate non-carcinogenic health effects, ATSDR has developed Minimal Risk Levels(MRLs) for contaminants commonly found at hazardous waste sites. This healthguideline is an estimate of a level of daily human exposure to a contaminant below whichnon-cancerous adverse health effects are unlikely. Since the contaminants of concern atthis site are classified as probable carcinogens (except naphthalene), MRLs cannot beused to evaluate the contaminants since there is no established threshold for carcinogeniceffects. This means there is an incremental probability, rather than a threshold, of anindividual developing cancer as a result of exposure to a carcinogen. This incrementalmeasurement is known as Lifetime Excess Cancer Risk (LECR), a unitless number. LECR is the product of the Average Daily Dose (ADD), the intake based on severalexposure parameters, and the Cancer Slope Factor (CSF), a linear estimate of theprobability of a response per unit intake of a chemical over a lifetime. CSFs arecommonly derived from animal data where actual exposures are hundreds to thousands oftimes higher than what is typical in actual human exposures.

The ADD of PAHs from the ingestion (eating) and dermal (skin) contact with surface soilcontaining PAH levels shown in Tables 4, 5 and 6 was calculated using the methods andassumptions shown in Tables 7, 8 and 9. Each exposure scenario is a conservative or"worst case" scenario, i.e., it assumes that a child would play exclusively in the area with contamination for the entire exposure duration. Actual exposures may be much lower.

Past exposure in Gardner-Roussel Park was determined separately from present andfuture exposure since the area with the highest levels of cPAHs was covered inNovember 2001. These include all samples in Table 2. There is no longer a completedexposure pathway (in the present or in the future) for these contaminants. The "worstcase" scenario for past exposure produces an LECR of 1.20x10-5 (12 additional cases inone million people similarly exposed over a lifetime) (Table 7). The LECR for presentand future exposures was lower, 3.66x10-7 (3 additional cases in ten million peoplesimilarly exposed over a lifetime) (Table 8). This represents a low to very low risk and isbelow levels that require action.

Using conservative exposure factors based on the EPCs on the Dr. Crisp School grounds,ADDs were calculated, shown in Table 9. For the "worst case" scenario (i.e., a childplaying exclusively on the areas where cPAHs were above the SQL), the LECR was7.29x10-7 (Table 9). This means that this specific scenario could result in 7.29 incidencesof cancer per ten million people; this is the number above the normally expected numberof cases. This represents a very low risk, and it is below levels requiring action. Theseconcentrations pose(d) no health threat through the two possible routes of exposure(ingestion and dermal absorption), in the past, present or future.

Health Outcome Data Review

Background

A health outcome data review is used to evaluate disease rates in a community. Theobjective is to determine if the rates of certain adverse health effects in a specific area arehigher than expected when compared to a reference population.

ATSDR follows a standard process to determine if health outcome data should bereviewed. If a completed exposure pathway exists and if there has been significantexposure to contaminants, which would lead to adverse health effects, then a healthoutcome data review is conducted. At the Gardner/Roussel Park and the groundssurrounding the Dr. Norman W. Crisp Elementary School, incidental ingestion anddermal exposure to contaminated surface soil, as well as inhalation of airborne PAHs areconsidered completed exposure pathways. Based upon the evaluation of theenvironmental data, adverse non-carcinogenic and carcinogenic health effects are notexpected to have occurred due to exposure to PAHs in surface soils at theGardner/Roussel Park. The environmental data available did not indicate sufficientexposure levels which would result in illness, and it was determined that a review ofhealth outcome data need not be warranted. However, through a public meeting heldwith community members and a public availability session held with the staff at the Dr.Crisp School, it was determined that the major community concern was cancer incidence. Because of this community concern, DHHS conducted an analysis of cancer incidencedata.

Methods

A descriptive epidemiological analysis was conducted at the ZIP code level using theStandardized Morbidity Ratio (SMR) technique. A detailed discussion of this techniqueis available in Appendix C.

Cancer Data

The health outcome data evaluation for the Gardner-Roussel Park/Dr. Crisp ElementarySchool site is based on an analysis of cancer data from the New Hampshire State CancerRegistry (NHSCR). The NHSCR maintains statistics for twenty-three types of cancer inNew Hampshire [9]. Once the NHSCR data were received, it was reviewed forpotential data quality issues (see Appendix C for details). These data were analyzedusing the most recent five-year time period (1994 through 1998). The five-year timeperiod was used for two reasons; (1) to ensure that there were a significant number ofcases, and (2) to match with data that were used for the standard comparison population. The standard comparison population data were obtained from the Surveillance,Epidemiology and End Results (SEER) program of the National Cancer Institute [10]. For each type of cancer, data were analyzed according to gender and age (0-4, 5-9, 80-84, and 85+ years).

Population Data

It was determined that a ZIP code analysis would be the smallest geographic area ofwhich cancer rates could be accurately calculated. This was concluded for a number ofreasons. First, age-specific population estimates are needed to assess disease rates forgeographic areas. Age-specific populations need to be estimated for intercensal years. For areas smaller than ZIP codes, these estimates are less reliable and often unreliable. Second, if the health outcomes are relatively rare, such as certain cancers, the numberswill be too small for reliable analyses to be conducted. This is an important reason forusing ZIP codes, which have relatively larger populations than do census tracts, for thiscomparative evaluation.

Between 1990 and 2000, ZIP codes within the city of Nashua changed (Figure 2). TheZIP code designated as 03060 in 1990 was divided into two new ZIP codes, 03060 and03064 in 1999. Cancer cases were selected by ZIP code 03060 since the analysis was onthe years 1994-1998 and this time period was prior to the ZIP code division. Forsimplicity, ZIP code area 03060 and 03064 will be referred to as 03060.

Population estimates for 1994 through 1998 were calculated by performing a linearinterpolation of the 1990 and 2000 Census data. Gender and age group distributionswere calculated for the ZIP code area using 1990 and 2000 Census data. The comparisongroup data were obtained from SEER [10].

This SMR analysis performed is descriptive in nature and should not be confused with anin-depth epidemiological study, which would involve a defined exposed population and adefined outcome. This type of evaluation cannot assess if there are links betweenparticular environmental factors and health outcomes. However, while these methodshave limitations, they satisfy the objective of this health outcome data review in that theycan help answer the community's questions regarding whether their community has morethan the expected number of cancer cases.

Results

The findings from our descriptive epidemiological analyses are illustrated in Table 10,titled "Cancer Incidence in ZIP Code 03060; Nashua, New Hampshire (1994-1998)". Thedata are presented, by gender, in tabular form with the heading of each column describingthe type of cancer, the expected number of cases for that particular type of cancer,followed by the observed number of cases for that specific cancer. A SMR and 95%confidence interval (a statistical test to determine if the probability is less than 5% that afinding is due to random fluctuation) have been calculated for each type of cancer.Cancer types with fewer than four observed cases were omitted from the table.This isdone to conform to the New Hampshire Bureau of Health Statistics and DataManagement's protocol on confidentiality in the release of cancer data.

After completing the SMR calculations, it was found that the rates for the following types of cancer were statistically elevated.

  • Esophageal Cancer in males (SMR 2.26)
  • Testicular Cancer in males (SMR 1.99)

Over two times (SMR 2.26) the expected number of esophageal cancer cases were seenin males living in ZIP code area 03060 in Nashua, New Hampshire. In addition, almosttwo times (SMR 1.99) the expected number of testicular cancer cases were seen.

Discussion of Results

Cancer Etiology

It is unknown why there are excess esophageal and testicular cancers in ZIP code area03060 in Nashua, NH, among the male population. The data available to the NewHampshire State Cancer Registry regarding individuals who have been diagnosed withcancer are limited and does not include information about known risk factors for specifictypes of cancer. It is unlikely that the elevated number of cases of cancer is due tochemicals found on the site. PAHs are not known to be associated with esophagealcancer or testicular cancer. In addition, the levels of PAHs on the site are at levelsunlikely to cause adverse health effects.

Cancer is not a single disease, but is made up of over 100 various types [11]. It ischaracterized by the uncontrolled growth and spread of abnormal cells. It can start in oneof many different organs or tissues in the body and, if it is not controlled throughtherapeutic methods, can spread (metastasize) to other organs throughout the body [12]. Based on research studies conducted on humans and animals, it has been determined thata variety of risk factors can be linked to increases in the chance of getting cancer. Riskfactors are different for each different type of cancer. However, some factors that aregenerally accepted to increase the risk of cancer include: smoking or chewing tobacco,family history of cancer, gender, race, certain hormones in the body, viruses, nutrition,exposure to radiation or some chemicals, sexual behavior, and excessive sunlightexposure [13].

The American Cancer Society estimates that nearly 1.3 million new cases of invasivecancer will be diagnosed in the United States in 2002. In New Hampshire, it is estimatedthat there will be 5,800 new cases in 2002 [11]. There were a total of 25,782 cases ofcancer reported to the NHSCR during the years 1994-1998 [9]. It has been furtherestimated that there are approximately 8.4 million persons living in the United Statestoday with some type of cancer. Nationally, the trends for both incidence and mortalityare decreasing. In New Hampshire, the trends in cancer rates (i.e. the most commontypes) are comparable to those of the SEER rates, which are used by the AmericanCancer Society to estimate national cancer trends [9].

Esophageal Cancer

Esophageal cancer is cancer of the esophagus, the muscular tube through which foodpasses from the throat to the stomach. Esophageal cancers are divided into two majortypes, adenocarcinoma or squamous cell carcinoma, depending on the type of cells thatare malignant. Both types of cancer are found in the tissue that lines the inside of theesophagus. Adenocarcinomas usually develop in the glandular tissue in the lower part ofthe esophagus near the stomach. Squamous cell cancers arise in squamous cells that linethe esophagus and these cancers usually occur in the upper and middle part of theesophagus.

Annually, approximately 13,200 Americans will be diagnosed with esophageal cancer. Itis three times more common among men than among women and two times morecommon among African Americans than among whites. Men and women between theages of 45 and 70 are at greatest risk. Data from the SEER program for 1994-1998 reportthe age-adjusted incidence of esophageal cancer in white males as 6.2 per 100,000(6.2/100,000) and white females as 1.6/100,000 [10]. This can be compared to NewHampshire's overall age-adjusted incidence during the same time period at 8.5/100,000for males and 2.1/100,000 for females [9]. Although a higher number of esophagealcancers were observed in males in ZIP code 03060 than would be expected, it isimportant to note that the rate for esophageal cancer in New Hampshire is alsosignificantly higher than the SEER rate.

Esophageal cancer is strongly associated with tobacco products. The longer a personuses tobacco, the higher the cancer risk. Another important risk factor is long-term heavydrinking. The combination of smoking and drinking alcohol raises a person's risk muchmore than using either substance alone. Individuals with Barrett's esophagus, a conditionassociated with long-term reflux of stomach fluids into the lower esophagus, are about 50times more likely than people without this condition to develop esophageal cancer. Persistent acid reflux (heartburn), diet that is deficient in certain nutrients such as fruitsand vegetables, and overeating, which leads to obesity, appear to be associated withesophageal cancer risk. Individuals with achalasia (a disease in which the loweresophagus does not relax), tylosis (formation of callouses), esophageal webs (abnormalprotrusions of tissue in the esophagus) and a history of a caustic ingestion 30 to 40 years earlier (e.g., lye) have higher risks for developing esophageal cancer [14].

Testicular Cancer

Testicular cancer affects the testicles (also called testes or gonads), which are a pair ofmale sex glands. They produce and store sperm, and are also the body's main source ofmale hormones. Testicular cancer can be broadly classified into two types: seminoma and nonseminoma. Seminomas make up about 30 percent of all testicular cancers.Nonseminomas are a group of cancers that include choriocarcinoma, embryonal carcinoma, teratoma, and yolk sac tumors. A testicular cancer may have a combination ofboth types [15].

Although testicular cancer accounts for only one percent of all cancers in men, it is themost common form of cancer in young men between the ages of 15 and 35. Any man canget testicular cancer, but it is more common in white men than in black men [16]. Datafrom the SEER program for 1994-1998 reports the age-adjusted incidence of testicularcancer in white males as 5.5/100,000. This can be compared to New Hampshire's overallage-adjusted incidence during the same time period at 4.7/100,000 [9].

The causes of testicular cancer are not known. However, studies show that several factorsincrease a man's chance of developing testicular cancer. Normally, the testicles descendinto the scrotum before birth. Males having had a testicle that did not move down intothe scrotum (undescended testicle or cryptor chidism) are at greater risk for developingthe disease. About 14% of cases of testicle cancer occur in men with a history ofcryptorchidism. Men with a family history of testicular cancer and men who havepreviously had testicular cancer are at greater risk of developing the disease. Nonseminoma germ cell tumors occur more frequently among men with certainoccupations (miners, oil and gas workers, utility workers, food and beverage processingworkers). Studies have not yet identified any specific chemicals as being responsible. There is some evidence that men infected with the human immunodeficiency virus(HIV), particularly those with AIDS, are at increased risk [16].

Community Health Concerns

When performing any public health assessment, DHHS gathers health concerns frompeople living or working on or near a site. The health concerns that people express arethen addressed in the public health assessment. At the Gardner-Roussel Park- Dr.Norman W. Crisp School site, DHHS accomplished this task through two activities:

  • On November 15, 2001 and December 12, 2001, DHHS staff attended publicmeetings.
  • On February 14, 2002, DHHS held a public availability session at the Dr. NormanW. Crisp School. School staff were able to meet with DHHS staff, in aconfidential setting, to discuss their health concerns and questions regarding theGardner/Roussel Park- Dr. Norman W. Crisp School site. The public availabilitysession was advertised through the monthly faculty meeting and through postersplaced throughout the school.

The following is a list of questions gathered from the public meeting, the publicavailability session and other written or verbal submissions. Since the residents' and thefaculty/staff's concerns are considered confidential, all comments have been paraphrasedto protect the identity of the respondent.

Community Questions

  1. Could any of the chemicals found at the site affect fertility or carrying a pregnancy to term?

It is unlikely that the low levels of contaminants detected in either the surface soil or in the air would cause women to have problems becoming pregnant or carrying a pregnancy to term. Studies that were conducted on animals found that mice that were fed high levels of one PAH (benzo[a]pyrene) during pregnancy had difficulty reproducing and so did their offspring. These offspring also had higher rates of birth defects and lower body weights. Similar effects could occur in people, but we have no information to show that these effects do occur [8].

  1. Could people living around the park be affected by asbestos?

The Gardner-Roussel Park sits on the site of a former landfill. It is known that asbestos waste was dumped in this landfill. The asbestos is in the subsurface soil. The wastes in the former landfill are covered so that individuals who use the park are not being exposed to it.

Asbestos-containing materials were found in subsurface soils near the foundation during the 1996 expansion of the Dr. Norman W. Crisp Elementary School. While construction was underway, the asbestos-containing materials were removed and New Hampshire DES took measures to insure that these wastes did not contaminate the inside of the school building.

  1. Did the environmental tests find any elevated contaminants?

The city of Nashua hired the consulting firm Camp Dresser & McKee Inc. to conduct sampling of the site for environmental contaminants. These tests included sampling the soil for the presence of PAHs in Gardner-Roussel Park and on the grounds of the Dr. Norman W. Crisp Elementary School and testing the indoor air of the school for airborne PAHs. A higher concentration of PAHs was found in surface soil on a slope located at the northwest end of the park. This area was covered with a 12 inch layer of clean soil. As a result, no one is presently coming in contact with PAHs.

  1. Will a health study be done to determine if children that played at the park 15-20 years ago were affected by contaminants at the site?

DHHS and ATSDR do not plan to conduct a health study of the community around the Gardner-Roussel Park- Dr. Norman W. Crisp Elementary School. In order to conduct a health study, a relationship between the environmental hazards at a site and adverse health outcomes must be biologically plausible. Also, people on or near the site would need to have been exposed to harmful levels of contaminants. Often, we would have to be able to measure this level of exposure for each person. At the Gardner-Roussel Park- Dr. Norman W. Crisp Elementary School an exposure pathways evaluation indicated that it is very unlikely that exposure to the low levels of PAHs detected in surface soils would result in adverse health effects.

  1. Are children safe playing on the school grounds, especially if they played in the areas where high concentrations of PAHs were detected?

The levels of PAHs detected in surface soils along the slope area were higher than concentrations detected in surface soils in other areas of the park. However, these levels are still below levels where we would expect to see adverse health effects. The degree of health hazard that may be posed by playing on the school grounds is related to how much soil contact a child has. Unfortunately, we do not know how long the soil has been contaminated, so we do not know how long children may have played in this soil. To adjust for this information gap, we made very conservative assumptions in our calculations. One of the conservative assumptions we made was that children played in the soil over a seven year period. Seven years represents if a child attended the Dr. Crisp School from kindergarten to grade six (see Tables 7-9, Appendix A). This represents a worst-case scenario. Making this conservative assumption means that our calculations are likely to be, if anything, more protective of health for most people than they would be if we had actual exposure information.

Even after assuming all of these "worst case" assumptions in the calculation of risk, DHHS found that these levels represent a very low cancer risk. It is unlikely that exposures will result in a carcinogenic effect that is significantly higher than background cancer rates.

In addition, it should be noted that PAHs are commonly found in urban soils. Their presence in the environment is due to the widespread practice of emptying fireplaces, stoves, boilers, garbage, etc. in urban (and rural) areas over the last several hundred years. As a result, it is very common to detect these levels of PAHs in the environment.

  1. Is there a risk for people participating in recreational activities at the park?

No increased risk was found, even if a child played exclusively in the areas of the "hot spot" (the slope in the northwest corner of the park, this area was covered with clean soil). As stated above, a "worst case" scenario was used in the estimation of risk of cancer (Table 7, Appendix A). It is likely that those participating in recreational activities would not remain exclusively on these areas considered in the risk calculation; thus, any risk would be considerably lower.

  1. Is it safe to breathe the air in the school?

Yes. After reviewing the air monitoring data, DHHS concluded that PAHs are not present in indoor air at concentrations that are high enough to cause individuals to become ill. Only one chemical, naphthalene, a non-carcinogenic PAH, was detected. However, the concentration of this chemical was well below the ATSDR comparison value. This means that the amount of substances in the air is unlikely, upon exposure, to cause adverse health effects. Based on this information, it is highly unlikely that children will experience adverse health effects from the very low levels of naphthalene that were detected in the school.

The naphthalene detected inside Dr. Crisp School is most likely unrelated to the PAHs detected in Gardner-Roussel Park. PAHs in grass-covered soil material do not migrate into air. Naphthalene has many sources related to human activity; some of these sources include oil furnaces and institutional cleaning products such as toilet deodorant bars. PAHs such as naphthalene are considered to be ubiquitous compounds, meaning that low levels can be commonly found in urban soil and indoor air.

  1. Were environmental tests conducted during the construction of the school?

No known tests were performed when the school was originally built. In 1996, the school was expanded. During this construction, asbestos was found in the soil around the foundation. DES conducted monitoring to ensure no asbestos contaminated the school. No other tests are known to have been performed.

On August 1, 2002, DHHS released the draft public health assessment for the Dr. Crisp School for public comment. The public comment period lasted for one month, from August 1 through August 30. The document was made available to local residents, government officials, and interested parties through mailings and upon request. Appendix H contains all of the written comments that DHHS received during this comment period. In this appendix, DHHS responds to these comments.


IV. ATSDR CHILD HEALTH INITIATIVE

The DHHS has prepared this Public Health Assessment under a cooperative agreement with ATSDR. DHHS has included the following information in accordance with the ATSDR's Child Health Initiative.

ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants and children demandspecial emphasis in communities faced with contamination of their water, soil, air, or food. Children are atgreater risk than adults from certain kinds of exposures to toxic chemical substances released to theenvironment. They are more likely to be exposed because children spend a significant amount of their timeplaying outdoors. They are shorter than adults, which means they breathe dust, soil and heavy vapors closeto the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight.The developing body systems of children can sustain permanent damage if toxic exposures occur duringcritical growth stages. Most importantly, children depend completely on adults for risk identification andmanagement decisions, housing and access to medical care.

Children are much more likely to expose themselves to soil contaminants through activities such asexploration and playing on or near the site. These contaminants can cling or adsorb to their outerwear, andpotentially expose individuals not directly associated with the site (family members, friends).

DHHS assumes that the majority of those individuals that may be potentially exposed at Gardner-RousselPark and the Dr. Crisp School to be children. Children are more likely to play, cross, come into contact with, and ingest the soil from these two areas.


V. CONCLUSIONS

DHHS has evaluated soil sampling data collected in 2001, from Gardner-Roussel Park and the grounds surrounding the Dr. Norman W. Crisp Elementary School, as well as ambient air samples from inside the school. Past exposures differed from present and future exposures because the City of Nashua took action and covered some soil in Gardner-Roussel Park. DHHS evaluated exposure scenarios for juveniles, since it assumes that a child represents the human receptor most likely to be exposed at these two areas.

  1. Current exposure to PAHs in surface soils at Gardner-Roussel Park constitutes a completed exposure pathway. Although exposure is occurring, DHHS has evaluated the potential for adverse health effects to occur using a "worst case" exposure scenario. DHHS has determined that exposure to existing levels of PAHs in surface soils does not represent a significant carcinogenic risk. According to ATSDR's hazard classification system, levels of PAHs found in surface soils pose no apparent public health hazard, presently or in the future. Moreover, the levels of PAHs currently existing in exposed surface soils are very similar to typical levels found in urban areas of New England.

  2. Past exposure to PAHs in surface soils at Gardner-Roussel Park constitutes a completed exposure pathway. Although exposure has occurred, DHHS has evaluated the potential for adverse health effects to occur using a "worst case" exposure scenario. DHHS has concluded that past exposure to PAHs in surface soils does not represent a significant carcinogenic risk. Levels of PAHs found in surface soils posed no apparent public health hazard during the past.

  3. Exposure to PAHs in surface soils on the grounds of the Dr. Norman W. Crisp Elementary School constitutes a completed exposure pathway. Although exposure is occurring, DHHS has evaluated the potential for adverse health effects to occur using a "worst case" exposure scenario. DHHS has concluded that exposure to PAHs in surface soils on the grounds of the school does not represent a significant carcinogenic risk. Levels of PAHs found in surface soils pose no apparent public health hazard, in the past, present or future. The levels of PAHs currently found in surface soils are very similar to typical levels found in urban areas of New England.

  4. Levels of airborne naphthalene inside Dr. Crisp Elementary School also pose no apparent public health hazard. Levels of PAHs were not only below the ATSDR Air Comparison Value (ACV), they were also below ambient levels usually found in indoor environments [17]. Levels below the HCV are unlikely to cause adverse health effects.

  5. Dioxin detected in surface soils in Gardner-Roussel Park pose no apparent public health hazard. Levels of dioxin were below the ATSDR HCV. Exposure to levels below the HCV is unlikely to cause adverse health effects.

  6. A standard morbidity ratio analysis for ZIP code 03060 in the City of Nashua, New Hampshire between 1994-1998 found that the rates of 21 out of 23 cancer types were within their expected ranges at the 95% confidence level. During the same time period, the incidence of testicular and esophageal cancer occurred more often then expected for males in ZIP code 03060.

  7. It is very unlikely that the excess cancers observed in ZIP code 03060 in Nashua, New Hampshire, are linked to the environmental exposures determined at the Gardner-Roussel Park and Dr. Norman W. Crisp Elementary School. PAHs are not known to be associated with esophageal cancer or testicular cancer. In addition, the levels of PAHs on the site are at levels unlikely to cause adverse health effects.

VII. RECOMMENDATIONS

  • The City of Nashua has been proactive in solving the issues related to this site. All recommendations to the City by DHHS have been carried out and are outlined below in the Public Health Action Plan.

  • This Bureau recommends that the citizens of Nashua try to reduce their chances of developing cancer by following the prevention guidelines issued by the American Cancer Society [11]. In general, those guidelines include:

    • Cessation of tobacco use.
    • Reduction of excessive alcohol use.
    • Limited or protected exposure to sunlight.
    • Increasing physical activities.
    • Practicing good nutritional habits.
    • Preventing infection from sexually transmitted diseases.
    • Self-examinations for cancers of the breast and skin.
    • A cancer-related checkup every three years for people between the ages of 20-40 and every year for people age 40 and older. This checkup should include examinations for cancers of the thyroid, oral cavity, skin, lymph nodes, testes and ovaries. Other types of cancer (breast, colon, rectum, prostate and uterus) have specific guidelines for routine screenings, which can be requested by any health care professional.

VII. PUBLIC HEALTH ACTION PLAN

The purpose of the Public Health Action Plan is to ensure that this document not only identifies any current or potential human health hazards, but also provides a plan of action to mitigate and prevent injuries or human health effects resulting from exposures to hazardous substances at the site. The first section of the Public Health Action Plan contains a description of completed or ongoing actions to mitigate exposures to environmental contamination. In the second section, there is a list of additional public health actions that will be implemented in the future.

Completed Actions

  • The City of Nashua has identified and characterized chemical contamination at the site.

  • In Gardner-Roussel Park, the City of Nashua covered the soils that had the highest PAH concentrations with 12 inches of clean soil.

Planned Actions

  • The City of Nashua is currently remediating all municipal parks to prevent exposure to any potential contaminants found on site. This includes upgrading drainage systems, improving soil cover and planting grass.

  • DHHS will evaluate any additional environmental sampling data that become available for Gardner-Roussel Park or the grounds around the Dr. Norman W. Crisp Elementary School.

  • The New Hampshire Department of Health and Human Services' Bureau of Health Risk Assessment will contact the Nashua Department of Public Health regarding the results of the health outcome data review.

PREPARERS OF THE REPORT

Todd C. Hudson, Environmental Health Risk Analyst
Melinda Carpenter, Environmental Epidemiologist
Gayle Bagley, Health Promotion Advisor
Dennis Pinski, Supervisor
Bureau of Health Risk Assessment
Office of Community & Public Health
New Hampshire Department of Health and Human Services
(603) 271-4664
(603) 271-3991 (fax)


REFERENCES

  1. City of Nashua. Personal correspondence from George Crombie to Todd Hudson (DHHS). Nashua Department of Public Works. December 20, 2001.

  2. U.S. Census Bureau. 2002. American FactFinder - Nashua, NH 1990 Census Data. Washington, D.C.: U.S. Census Bureau, U.S. Department of Commerce. http://factfinder.census.gov/servlet/BasicFactsServlet

  3. GZA Environmental Inc. 2001. Draft Site Investigation of Roussel Park Nashua, New Hampshire.

  4. USEPA (U.S. Environmental Protection Agency), Region IV. 2000. Region IV Human Health Risk Assessment Bulletins; Supplement to Risk Assessment Guidance for Superfund (RAGS). Atlanta: US Environmental Protection Agency Region IV, Waste Management Division. http://www.epa.gov/region04/waste/ots/healtbul.htm.

  5. USEPA (U.S. Environmental Protection Agency). 1989. Risk Assessment Guidance for Superfund, Chapter 5: Data Assessment and Data Evaluation. Washington, DC: U.S. Environmental Protection Agency, Office of Emergency and Remedial Response, EPA 540/1-89/002.

  6. Bradley, LJN; Magee, BH; Allen SL. 1994. Background levels of polycyclic aromatic hydrocarbons (PAH) and selected metals in New England Urban Soils. Journal of Soil Contamination, 3(4): 349-361.

  7. Camp Dresser & McKee Inc. 2002. Human Health Risk Characterization for Roussel Park/Dr. Norman W. Crisp Elementary School; 50 Arlington Street, Nashua, New Hampshire.

  8. ATSDR (Agency for Toxic Substances and Disease Registry). 1995. Toxicological Profile for Polycyclic Aromatic Hydrocarbons. Atlanta, Georgia: Agency for Toxic Substances and Disease Registry, U.S. Department of Health and Human Services.

  9. New Hampshire State Cancer Registry. 1999. Cancer in New Hampshire, 1998. Hanover, New Hampshire.

  10. National Cancer Institute. 2001. Surveillance, Epidemiology, and End Results (SEER) Program Public-Use Data, 1973-1998. Rockville, Maryland: National Cancer Institute, Division of Cancer Control and Population Sciences, Cancer Surveillance Research Program, Cancer Statistics Branch.

  11. American Cancer Society. 2002. Cancer Facts & Figures - 2002. Atlanta, Georgia, American Cancer Society.

  12. McKinnell Robert, et al. 1998. The Biological Basis of Cancer. New York: Cambridge University Press 1998. pp. 79-114.

  13. Brownson R., et al. 1998. Chronic Disease Epidemiology and Control, 2nd Ed. Washington, DC: American Public Health Association 1998. p. 335-340.

  14. American Cancer Society. 2002. What Are the Risk Factors for Esophagus Cancer? Atlanta, Georgia: American Cancer Society. http://www.cancer.org/docroot/CRI/content/CRI_2_4_2X_What_are_the_risk_factors_for_esophagus_cancer_12.asp?sitearea=CRI

  15. National Cancer Institute. Questions and Answers About Testicular Cancer. 2000. Rockville, Maryland: National Cancer Institute, National Institutes of Health.

  16. American Cancer Society 2002. What Are the Risk Factors for Testicular Cancer? Atlanta, Georgia: American Cancer Society. http://www.cancer.org/docroot/CRI/content/CRI_2_4_2X_What_are_the_risk_factors_for_testicular_cancer_41.asp?sitearea=CRI

  17. R. Rudel, in J.D. Spengler, J.M. Sanet, and J.F. McCarthy, Indoor Air Quality Handbook. 2000. McGraw-Hill, New York, pp. 34.

  18. USEPA (U.S. Environmental Protection Agency). 1997. Exposure Factors Handbook. Washington, DC: U.S. Environmental Protection Agency, National Center for Environmental Assessment, EPA 600/P-95/002Fa.

  19. NHDES (New Hampshire Department of Environmental Services). 1998. Contaminated Sites Risk Characterization and Management Policy. Concord, NH: NH Department of Environmental Services.

  20. RAIS (Risk Assessment Information System). 2001. Chemical-specific toxicity values. Oak Ridge, TN: Center for Risk Excellence. http://risk.lsd.ornl.gov/index.shtml

  21. USEPA (U.S. Environmental Protection Agency). 2001. Risk Assessment Guidance for Superfund, Volume I, Part E: Supplemental Guidance for Dermal Risk Assessment. Interim Guidance. Washington, DC: U.S. Office of Emergency and Remedial Response, Environmental Protection Agency.

CERTIFICATION

The Public Health Assessment for the Gardner-Roussel Park and the Dr. Norman W. CrispElementary School in Nashua, New Hampshire was prepared by the New HampshireDepartment of Health and Human Services under a cooperative agreement with theAgency for Toxic Substances and Disease Registry (ATSDR). It is in accordance withapproved methodology and procedures existing at the time the public health assessmentwas initiated.

Gregory V. Ulirsch
Technical Project Officer, SPS, SSAB, DHAC


The Division of Health Assessment and Consultation (DHAC), ATSDR, has reviewedthis Public Health Assessment and concurs with its findings.

Lisa C. Hayes
for Chief, SSAB, DHAC, ATSDR



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