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PUBLIC HEALTH ASSESSMENT
NEWHALL STREET NEIGHBORHOOD
(a/k/a Bryden and Morse Streets Residential Properties, CERCLIS No. CTN000103143)
(a/k/a Rosem Site Residential Properties, CERCLIS No. CTN000103142)
HAMDEN, NEW HAVEN COUNTY, CONNECTICUT
September 9, 2004


Discussion

This section presents results from environmental sampling. Environmental data are presented and discussed along with relevant health-based comparison values. Comparison values are screening levels, below which, there is little likelihood of adverse health effects from exposure. When contaminant concentrations are below comparison values, no further evaluation for human health is necessary and it can be concluded that adverse health impacts are not likely. When contaminant concentrations exceed comparison values, it indicates that further evaluation of exposures and health impacts is needed. Comparison values used in this PHA are from the Connecticut Remediation Standard Regulations (CT RSRs) residential direct exposure criteria for soil (CT DEP 1996). Comparison values are presented in the data tables in the Environmental Data section.

Trigger concentrations were another set of values used to evaluate soil data from the Newhall Street neighborhood. These are not the same as comparison values. Trigger concentrations are levels that indicate the need for immediate action by EPA to reduce exposure. Trigger concentrations used for the Newhall Street neighborhood soil data were developed by CT DPH and EPA for this project. They are higher than CT RSRs because they indicate where contaminant levels are so high that immediate action is needed. As discussed in greater detail in the following section, EPA used the trigger concentrations to identify which properties needed immediate soil removal actions.

Exposure pathways (i.e., ways people could come into contact with contamination) and the public health significance of these exposures, along with an evaluation of available health outcome data, are also discussed in this Section.

Environmental Data

As mentioned in the Background Section, state and federal agencies have conducted soil sampling in the Newhall Street neighborhood on several occasions. CT DEP conducted the initial sampling effort in January 2001, focusing on public right-of-way grass strips between the sidewalk and road in locations believed to have received fill. This was followed by EPA sampling of surface soils to identify properties where immediate action was necessary. After EPA completed its surface soil sampling effort, CT DEP continued to sample soil at properties who requested soil sampling. The final dataset evaluated in this PHA consists of soil samples collected by the Olin Corporation in August 2002.

CT DEP Right-Of-Way Soil Sampling

Beginning in January 2001, CT DEP collected surface soil samples (0-6 inches below ground surface) from 65 locations in right-of-way grass strips. At eight of these locations, soils at depth were collected as well. Depth samples were collected as much as 12 feet below ground surface. Samples were analyzed for total metals, pesticides, semivolatile organic chemicals (SVOCs), volatile organic chemicals (VOCs), and extractable total petroleum hydrocarbons (ETPH).

In the right-of-way samples, polycyclic aromatic hydrocarbons (PAHs) were the contaminants found most often at levels exceeding health-based comparison values (15 out of 65 samples). PAHs were more often elevated in surface soil than at soil at depth. Maximum concentrations of PAHs in surface soils are 2-5 times above comparison values. Lead, arsenic, ETPH, and pesticides were also found at levels exceeding comparison values. However, pesticides were elevated only in surface samples and were infrequently detected at elevated levels. Field observations during sampling noted the presence of non-native materials such as ash and cinders. The right-of-way sampling effort is significant because it was the first data to show that landfill waste extends into residential areas beyond the Hamden Middle School2.

The right-of-way sample results for surface soils are summarized in Table 1. Table 1 includes maximum concentrations for those contaminants detected above health-based comparison values. Results from soils at depth (samples collected by both CT DEP and EPA) are summarized in Table 2.

EPA Residential Soil Sampling

The results of the CT DEP right-of-way sampling prompted CT DEP to ask EPA to conduct a residential soil sampling program to determine if contaminant levels were high enough that immediate action was needed to reduce exposure. In April 2001, EPA sampled surface soils (0-6 inches) at 76 properties. Sampling focused on accessible surface soils in yards where people work and play. In each yard, EPA targeted its sampling on children's play areas, bare soil areas, gardens and any other areas likely to receive high use. In addition, EPA sampled areas where homeowners had observed non-native soil material (e.g., ash, glass, cinders, slag, or other debris). Four or five locations on each property were sampled and field analyzed for lead, arsenic, and mercury using x-ray fluorescence (XRF). Approximately 40% of the XRF samples were sent to EPA's laboratory for confirmatory analysis. At the single location on each property with the highest lead level, a soil sample was laboratory analyzed for SVOCs, including PAHs.

EPA's sampling indicated that there were properties that had contaminant levels high enough that immediate action was needed to reduce exposure. The immediate action implemented by EPA was removal of contaminated soil to a depth of 18 inches below ground surface and disposal at an offsite location. Properties were considered for immediate action by EPA if contaminants in surface soil exceeded trigger levels3 developed by CT DPH in collaboration with EPA, CT DEP, and the QVHD. At properties where surface soil concentrations exceeded trigger levels, EPA collected additional surface soil samples and at least one depth sample. The purpose of the additional sampling was to confirm the presence of contaminants above trigger levels and rule out lead paint as the source of elevated lead in surface soil. If, through additional sampling, a property was identified to receive an immediate action, EPA conducted a third round of sampling. This round of sampling provided a more complete characterization of the extent of contamination. It involved sampling surface soil at 10-foot grid intervals and field screening the samples for lead using XRF. This more detailed characterization allowed EPA to more precisely define the horizontal extent of contamination across the yard and develop work plans for where and how much soil removal would occur. Because sampling data indicated that high arsenic and PAHs almost always occurred with high lead levels, EPA made decisions about soil removal based only on lead results.

Table 1.

Summary of Surface Soil Samples (0-6 inches) Collected by CT DEP from Right-Of-Way Areas, Newhall Street Neighborhood, Hamden, Connecticut, January 2001.
Chemical Maximum Concentration (mg/kg) # Samples above Comparison Value/Total # samples Comparison Value(mg/kg)
Lead 4,173 3/65 400
Arsenic 98 5/65 10
ETPH* 716 2/65 500
Chromium 104§ 1/65 3,900/100§
PAHs
Benzo(b)fluoranthene 5 15/81 1
Benzo(a)pyrene 2.5 5/65 1
Benzo(a)anthracene 2.6 6/65 1
Benzo(k)fluoranthene 2.3 0/65 8.4
Dibenzo(ah)anthracene 0.59 0/65 1
Indeno(1,2,3-cd)pyrene 2 3/65 1
Pesticides
Chlordane (total) 17 3/65 0.49
Heptachlor 0.4 1/65 0.14
beta-BHC 1.6 1/65 0.34
Dieldrin 0.05 1/65 0.038
* ETPH = extractable total petroleum hydrocarbons
† The source for all comparison values used in this health assessment (unless otherwise noted) is the Connecticut Remediation Standard Regulations (CT RSR) residential direct exposure criteria for soil (CT DEP 1996). These soil standards are developed to be protective of a child who contacts soil on a daily basis for many years (30 years).
‡ CT DEP site-specific cleanup criterion at the Hamden landfill sites. This criterion will eventually become part of the CT RSR and will be used statewide.
§ The CT RSR residential criteria for trivalent chromium is 3,900 mg/kg, the CT RSR value for hexavalent chromium is 100 mg/kg. The sample was not speciated so it is unknown how much of the chromium is hexavalent.


Table 2.

Summary of Subsurface Soil Samples Collected by CT DEP and EPA, Hamden, Connecticut, 2001-2002.
Chemical Maximum Concentration (mg/kg) Sample Depth (feet) # Samples above Comp. Value/Total # Samples Comparison Value (mg/kg)
Lead 39,400 5.5-6 89/166 400
Arsenic 347 3-3.5 55/157 10
Mercury 70 1.5 1/145 20
Chromium§ 114 2-7 1/145 3,900/100§
ETPH* 15,450 1-4 2/129 500
PAHs
Benzo(b)fluoranthene 350 3-4.5 61 /142 1
Benzo(a)pyrene 240 3-4.5 60/142 1
Benzo(a)anthracene 230 3-4.5 56/142 1
Benzo(k)fluoranthene 250 3-4.5 50/142 8.4
Dibenzo(ah)anthracene 18 1-4 6/142 1
Indeno(1,2,3-cd)pyrene 52 3-4.5 17/142 1
* ETPH = Extractable total petroleum hydrocarbons.
† The source for all comparison values used in this health assessment (unless otherwise noted) is the Connecticut Remediation Standard Regulations (CT RSR) residential direct exposure criteria for soil (CT DEP 1996). These soil standards are developed to be protective of a child who contacts soil on a daily basis for many years (30 years).
‡ CT DEP site-specific cleanup criterion at the Hamden landfill sites. This criterion will eventually become part of the CT RSR and will be used statewide.
§ The CT RSR residential criteria for trivalent chromium is 3,900 mg/kg, the CT RSR value for hexavalent chromium is 100 mg/kg. The sample was not speciated so it is unknown how much of the chromium is hexavalent.


EPA conducted soil removal actions on 13 properties from October 2001 to January 2002. CT DPH reviewed and concurred with EPA's actions and assured that it was health protective (see letter in Attachment D). As mentioned previously, EPA removed soils to a depth of approximately 18 inches and then backfilled the excavation with clean fill. To gain a better understanding of contaminant concentrations at depth at the 13 properties, CT DEP collected soil samples at the base of the excavation before it was backfilled by EPA.

All of EPA's residential surface soil sampling results are summarized in Table 3. Depth samples collected by EPA and CT DEP are summarized in Table 2. Table 2 includes depth samples collected by EPA from residential yards, depth samples collected by CT DEP at the base of excavations, and depth samples from right-of-way areas.

Table 3.

Summary of Surface Soil Samples (0-6 inches) Collected by EPA from Residential Yards in the Newhall Street Neighborhood, Hamden, Connecticut, April 2001.
Chemical Maximum Concentration (mg/kg) # Samples above Comp. Value/ Total # Samples Comparison Value (mg/kg) # Samples above Trigger Concentration Trigger Concentration§ (mg/kg)
Lead 43,900 476/884 400 91/884 1,200
Arsenic* 155 15/85 10 1/85 150
PAHs
Benzo(b)-fluoranthene 50 41/69 1 - -
Benzo(a)-pyrene 54 41/69 1 2/69 10
Benzo(a)-anthracene 48 30/69 1 - -
Benzo(k)-fluoranthene 46 3/69 8.4 - -
Dibenzo(ah)-anthracene 12 6/69 1 - -
Indeno(1,2,3-cd)pyrene 30 25/69 1 - -
* Results presented for arsenic are laboratory results, not the field screening (XRF) results. Laboratory results are presented because the arsenic detection limit for XRF was 60 mg/kg, which is higher than the comparison value for arsenic of 10 mg/kg.
† The source for all comparison values used in this health assessment (unless otherwise noted) is the Connecticut Remediation Standard Regulations (CT RSR) residential direct exposure criteria for soil (CT DEP 1996). These soil standards are developed to be protective of a child who contacts soil on a daily basis for many years (30 years).
‡ CT DEP site-specific cleanup criterion at the Hamden landfill sites. This criterion will eventually become part of the CT RSR and will be used statewide.
§ The trigger concentrations were developed jointly by CT DEP, EPA, and CT DPH for this project. Trigger concentrations indicate the need for immediate soil removal actions.


Table 3 shows that lead was found in surface soil at extremely high levels (up to 43,900 milligrams per kilogram [mg/kg]). This is more than 100 times greater than the comparison value of 400 mg/kg. The comparison value of 400 is a screening level below which there is little likelihood of adverse health effects. Arsenic was found in surface soil at levels as high as 155 mg/kg (15 times greater than the comparison value). However, arsenic was not detected above the comparison value as frequently as lead. Virtually all of the samples with elevated arsenic also had elevated lead. With regard to PAHs, several properties in the neighborhood hade concentrations of PAHs above comparison values. In virtually all cases, properties with elevated

PAHs also had elevated lead. The highest levels of PAHs found on a property were as much as 50 times greater than comparison values.

During soil removal activities, EPA conducted perimeter air monitoring using two personal data real-time aerosol monitors (RAMs) which were placed upwind and down wind of the work area. The RAMs monitored dust levels in real time and ensured that dust suppression measures were performing within established guidelines. In addition, four low-flow air sampling pumps were placed along the perimeter of the work zone to verify that airborne lead in dust, if present, was not migrating beyond the work areas. Personal air monitoring for airborne lead was conducted during the first 3 days of excavation work. Personal monitoring was discontinued because analytical results indicated no elevated levels of lead in the air.

CT DEP Supplemental Soil Sampling

As mentioned previously, soil data were also collected by CT DEP as part of its supplemental soil-sampling program. CT DEP's supplemental soil sampling program included residences that were not included in EPA's sampling program, but there was reason to suspect that landfill waste materials were present in soil on those properties. Beginning in December 2001, CT DEP collected surface soil samples at approximately 46 residences not sampled by EPA. CT DEP followed essentially the same sampling procedure as EPA had followed for its April 2001 sampling effort. CT DEP's sampling identified the presence of lead in surface soil at levels up to 5,600 mg/kg (14 times greater than the comparison value). There were eight properties with lead levels greater than the immediate action trigger level of 1,200 mg/kg. At these properties, exposure reduction measures such as covering bare soil were performed. Arsenic was also found at levels greater than the comparison value of 10 mg/kg (maximum concentration 55 mg/kg). Several PAHs were found at levels as great as 40 times above comparison values in one surface soil location at one property. EPA did not conduct soil removal actions at these properties because they were discovered after EPA had already completed its activities in the neighborhood. These properties are being investigated further as part of Olin's workplan for additional soil sampling in the neighborhood. CT DEP's supplemental soil sampling results are not included in the summary data tables.

Olin Soil Sampling

The final soil data that exists for the Newhall Street neighborhood consists of samples collected and analyzed by Olin Corporation in August 2002. As mentioned earlier, the focus of Olin's sampling was to better define the extent of fill material at depth in the neighborhood and to define the limits of landfill waste materials. Although their focus was soils at depth, they collected approximately 75 surface soil samples (0-3 inches below ground surface) as part of their investigation. Some samples were collected from public right-of-way areas, other samples were collected from private yards. Surface soils were analyzed for lead and arsenic. The maximum lead concentration in surface soil was 738 mg/kg; the maximum arsenic concentration was 35 mg/kg. These concentrations are above comparison values, but do not exceed the immediate action trigger value. Regarding contaminant concentrations at depth, Olin's results were generally consistent with what previous subsurface investigations have found. That is, lead, arsenic, PAHs, and ETPHs were found at elevated levels. Maximum lead found in soils at depth was 10,100 mg/kg and maximum arsenic was 303 mg/kg. A new finding was that at one property, PAHs were found at depth (2-4 feet below ground surface) at levels much higher than any previous sampling had found. Several PAH compounds were found at 96 to 3,100 times greater than comparison values. Olin's dataset is not included in the summary data tables.

Exposure Pathways

To evaluate potential exposures in the Newhall Street neighborhood, CT DPH considered the available environmental data and how people might come into contact with contaminants. In order for exposure to occur, there must be a source of hazardous contaminants, a way for people to come into direct contact with the contaminants, and a way for the contaminants to enter the body. It is important to emphasize that if there is no exposure to a hazardous contaminant, there is no risk of adverse health effects.

In the Newhall Street neighborhood, contaminants have been detected in surface soil and subsurface soil.

Surface soil

For surface soil, possible ways people could be exposed to contamination is by ingestion (eating soil particles adhered to fingers or food items), dermal contact (skin contact with soil during activities such as gardening or other yard work, children playing in the soil) and inhalation (inhaling soil particles). In yard areas that are grassed or have other barriers to direct soil contact, such as asphalt, exposure potential to surface soils will be greatly diminished. For this PHA, exposure to contaminants in surface soils is considered to be a complete exposure pathway and is evaluated in more detail in the Public Health Implications section.

Subsurface soil

Subsurface soils in the neighborhood were also found to have contaminants. As summarized in Table 2, contaminant levels in soils at depth are significantly elevated above health-based comparison values. In the past, it is possible that neighborhood residents could have come into contact with soils at depth during activities in their yards that penetrated into deep soils. Such activities could have included planting trees or shrubs and installing fence posts or footings for a deck. It is very difficult to quantitatively evaluate doses and health impacts to residents from past exposure to soils at depth.

Because contaminant levels in subsurface soils are high, CT DPH has conducted a number of public health intervention activities to inform residents about the contamination and recommend ways to avoid contact with subsurface soils. These interventions included home visits with residents, preparing and distributing fact sheets, and presenting information at numerous public meetings and availability sessions. CT DPH continues to distribute its fact sheets and continues to communicate its message about avoiding activities that penetrate into deep soils. Because of CT DPH's ongoing interventions, the current potential for exposure to soils at depth is very low. Therefore, CT DPH considers exposure to subsurface soils to be a potential exposure pathway and it is not evaluated quantitatively in this Public Health Assessment.

With regard to exposure pathways other than soil, air monitoring conducted during EPA's soil excavation work showed no airborne lead and the methane screening program found no evidence of methane in the basements of homes in the neighborhood that were tested. Therefore, exposure to landfill waste materials through the air pathway (indoor air and outdoor air) is not likely.

Contaminants have been detected in groundwater in the neighborhood. However, groundwater is not used for drinking water or other nonpotable uses, so there is no exposure to groundwater from drinking5.

If there is no potential for exposure to contaminants, then it can be concluded that there is no possibility of adverse health effects from the contaminants. However, if there is an actual (completed) or potential exposure pathway, contaminant concentrations are compared to health-protective comparison values. As stated previously, comparison values are screening levels, below which, there is little likelihood of an adverse health effects from exposure. When contaminant concentrations exceed comparison values, exposures are evaluated further. In this Public Health Assessment, CT DPH used the Connecticut residential criteria for direct exposure to soil (CT RSRs) as comparison values. These values assume that contact with soil occurs every day over the long term (30 years).

Public Health Implications for Adults and Children

This section presents the likely health impacts to Newhall Street neighborhood residents from hazardous contaminants in landfill waste. Whether a person becomes sick from exposure to hazardous contamination depends on a number of factors including:
  • the concentration of the chemical someone is exposed to (how much),
  • the duration and frequency of exposure (how long, how many times),
  • the route of exposure (breathing, eating/drinking, skin contact), and
  • the person's individual characteristics (age, diet, lifestyle, genetics).
To evaluate public health implications to adults and children from contaminants in residential yards in the Newhall Street neighborhood, CT DPH first compared maximum concentrations of contaminants with comparison values. When concentrations exceeded comparison values, they were evaluated further to determine the likelihood that the exposures would be significant enough to cause health effects. For contaminants that exceeded comparison values (lead, arsenic, PAHs, pesticides, total petroleum hydrocarbons), CT DPH evaluated potential cancer and noncancer health effects. For lead, CT DPH evaluated the predicted increase in blood lead level.

See Attachment F for a summary of the general toxicological and epidemiological information for the three primary contaminants found in the Newhall Street neighborhood (lead, arsenic, and PAHs). The information in Attachment F is included as general background information. It is not intended to imply that these health effects would be expected or are likely to occur among residents in the neighborhood. More toxicological information can also be found on the ATSDR website (www.atsdr.cdc.gov).

Public Health Implications of Lead in Surface Soil

Substantial amounts of environmental sampling have occurred in the Newhall Street neighborhood over the past 3 years. Surface soil samples collected from neighborhood yards (Table 3) indicate that lead was frequently found above its comparison value of 400 mg/kg. Lead is the contaminant found at the highest concentration in surface soil, relative to its comparison value. Lead was detected at one property at concentrations more than 100 times above its comparison value. The maximum lead level found in surface soil in a residential yard is 43,900 mg/kg. Lead was found at levels above 400 mg/kg in approximately 50% of samples.

Adults and children in the Newhall Street neighborhood could come into direct contact with contaminated surface soil while working or playing in their yards. Exposure could occur through direct skin contact (dermal), eating soil particles adhered to fingers or food items (ingestion) or breathing soil particles in the air (inhalation). Children have a greater potential for exposure to soil than do adults. Children have more opportunities for contact with soil because they play on the ground and in bare soil. Children also have greater hand-mouth activity, which leads to more soil ingestion than is common for adults. In addition, children have a greater sensitivity than do adults to the harmful health effects from lead exposure.

The high levels of lead found in the Newhall Street neighborhood were present in surface soils where children currently reside or resided in the past. As discussed previously, lead in soil can be an important route of exposure to lead.

ATSDR has developed a screening procedure for evaluating exposures to lead (ATSDR 1999). ATSDR's screening procedure uses a blood lead slope factor, which predicts the increase in blood lead per unit lead concentration in soil. The slope factor assumes continuous exposure. The screening procedure involves multiplying the lead level in soil by the percentage of outside time a person spends in their yard. This is then multiplied by the blood lead-to-soil lead slope factor. CT DPH used a blood lead slope factor for U.S. children of 0.0068, which is derived from a study of U.S. children from 1-18 years of age (Angle et al. 1984). For adults, CT DPH used a slope factor of 0.001, which is based results from a study of U.S. males aged 18-65 years (Stern 1996). For the percentage of outside time spent in the yard, CT DPH made two alternative assumptions, shown in Table 4.

The relationship between soil lead and blood lead depends on many factors, including the bioavailability6 of lead in the soil, the chemical form of lead, the age of the exposed person, and the person's work or play habits. Using the ATSDR screening procedure, CT DPH estimated the incremental blood lead level for children and adults working and playing in soil in the yard with the highest average lead level (calculated to be 11,800 mg/kg). Lead levels were not averaged across multiple yards because exposure occurs mostly in one's own yard rather than in other yards in the neighborhood. The average lead concentration (11,800 mg/kg) was conservatively estimated as the 95% upper confidence limit (UCL) of the mean, using EPA's Pro UCL program (EPA 2001a). The results of the blood lead estimates are presented in Table 4.

For our calculations, we assumed that a child spends 100% of their playtime in their yard (as opposed to playtime spent elsewhere, such as at a park). That child might have an incremental blood lead level of 80 µg/dL (microgram per deciliter), estimated from the average (11,800 mg/kg) lead concentration in soil. If the children spend only 50% of their playtime in their yard, CT DPH then estimates a potential incremental blood lead level of 40 µg/dL for those children, using the average concentration in the most contaminated yard. CT DPH believes it is reasonable to assume that children would not spend less than 50% of their playtime in their yards.

These blood lead estimates are greater than the level of concern for potential adverse health impacts in children (greater than 10 µg/dL). It is important to note that 11,800 mg/kg is the average lead level in the most contaminated yard7. Estimated blood lead levels would be lower in yards with lower lead levels in soil. For example, using the ATSDR screening procedure, any yard with an average soil lead concentration exceeding 1,500 mg/kg has the potential to result in blood lead levels greater than the level of concern for children (>10 µg/dL). This assumes that the child spends 100% of his or her play time in their yard. Average lead levels in several yards exceeded 1,500 mg/kg, but they have already been cleaned up by EPA (as has the yard with an average lead level of 11,800 mg/kg). Therefore, under current conditions, there is no opportunity for exposure to lead at levels of public health concern.

Table 4.

Estimated Blood Lead Increment from Exposure to Lead in Residential Soil, Newhall Street Neighborhood, Hamden, Connecticut (using ATSDR's Screening Procedure, July 1999).
Exposed Person Soil Lead Concentration* (mg/kg) Soil Slope Factor (µg/dL blood lead per mg/kg soil lead) Fraction of play or work time spent in one's own yard Estimated Incremental Blood Lead Burden (µg/dL)
Child 11,800 0.0068 1.0 (100%) 80
Child 11,800 0.0068 0.5 (50%) 40
Adult 11,800 0.001 0.5 (50%) 6
*The soil lead concentration of 11,800 mg/kg is the average concentration in the most contaminated yard. The average was conservatively estimated as the 95% upper confidence limit of the average. It is unlikely to underestimate the true average.


CT DPH's blood lead calculations show that estimates of incremental blood lead levels in children are above levels of concern for potential adverse health impacts (>10 µg/dL). However, there is no indication that children living in the neighborhood actually have these levels of lead in their blood. The model used by CT DPH is a screening procedure that cannot predict the true blood lead levels in any given person because of the many uncertainties inherent in the relationship between soil lead and blood lead.8 At best, the model results indicate that at the most contaminated properties, there is the potential for increases in blood lead levels in children. At properties with lower lead levels in soil, the potential for exposure would be less. Fortunately, the homes with the highest levels of lead in surface soil that we know about, received immediate soil removal actions by EPA in 2001. Therefore, CT DPH believes that exposures at levels of public health concern are no longer occurring in the neighborhood. CT DPH has concluded that under current conditions in the neighborhood, lead does not pose a public health threat. However, past exposures to lead in soil could have caused elevations in children's' blood lead above levels of concern for possible adverse health effects. Elevations in children's blood lead could occur in the future if the remaining properties with elevated lead in soil are not cleaned up. As shown in Table 4, CT DPH also estimated incremental blood lead levels in adults and found the estimated increase to be small and not above a levels of concern for adults (>20 µg/dL).

Public Health Implications of Other Contaminants in Surface Soil

Arsenic and PAHs

As shown in Table 3, arsenic was found in surface soil at levels above comparison values. The maximum arsenic concentration was 155 mg/kg (15 times higher than the comparison value). Several PAHs were also found at elevated levels (as much as 54 times above comparison values). Only a single surface soil sample from each yard was analyzed for PAHs. For arsenic, most properties only have two or three laboratory confirmed samples9. The small number of samples is not enough to calculate averages on a property-by-property basis for arsenic and PAHs. Therefore, to estimate concentrations of arsenic and PAHs that residents could be exposed to, CT DPH calculated average concentrations of arsenic and PAHs using data from multiple properties. Properties in the neighborhood were separated into two groups according to the spatial distribution of landfill waste.

Morse Street Property Group

The first group of properties (Morse Street group), consists of six different properties. In this property group, six PAH samples and 13 arsenic samples were available to calculate average concentrations. The average concentration (95% UCL) for each PAH was below comparison values (CT RSRs). Therefore, PAH exposure in this group of properties is unlikely to present a cancer or noncancer health threat. The average concentration (95% UCL) of arsenic in the Morse Street group of properties was 54 mg/kg. This average concentration exceeds the comparison value for arsenic of 10 mg/kg, so exposures to arsenic in the Morse Street group of properties were evaluated further.

CT DPH calculated exposure doses and theoretical risks from exposure to arsenic in the Morse Street group of properties, assuming that soil exposure occurs 7 days per week for 9 months of the year, for 30 years. The calculations are based on 9 months rather than 12 months, on the assumption that contact with soil would not occur during the winter, when the ground is frozen and possibly snow-covered. CT DPH believes these are realistic, yet still health-protective assumptions, given the specifics of the site. Arsenic doses to children and adults were calculated. As previously stated, CT DPH assumed people would be exposed to 54 mg/kg arsenic in soil. This is the 95% UCL of the average. A 95% UCL accounts for variability in the data and ensures that the average is not underestimated. Given these assumptions, the average daily dose from ingestion and dermal exposure to arsenic was estimated to be 0.00026 mg/kg/day. This dose is below the Agency for Toxic Substances and Disease Registry's (ATSDR's) minimum risk level (MRL) for chronic oral arsenic exposure of 0.00034 mg/kg/day. MRLs are estimates of daily exposure to humans that are likely to be without harmful noncancer effects. Because the dose from the site is less than the MRL, harmful noncancer effects from arsenic in soil are unlikely. See Attachment G for the detailed calculations.

Because arsenic can be an acute (short-term) toxin, CT DPH also calculated an acute ingestion dose for a 2-year-old child assuming a larger soil ingestion rate over a 7-day period. The acute calculation focused on a young child because younger children are more likely to ingest soil than are older children. The acute dose from the site is three times less than ATSDR's Acute MRL. Thus, adverse health effects from acute oral exposure to arsenic in the soil are unlikely. See Attachment G for the detailed calculations.

CT DPH also calculated theoretical cancer risks from long-term exposure to arsenic (assuming exposure from age one to age 30 years). The theoretical cancer risk from arsenic exposure of 5 x 10-5 (five excess cancer cases per 100,000 exposed people) represents a non-meaningful incremental cancer risk above the background cancer level of approximately one in three (NCI 2001). Another way to describe the background cancer rate of one in three is that in a population of 100,000 people, roughly 33,000 of them would be expected to get cancer at some point in their lifetime. If that same population of 100,000 people were exposed to arsenic in soil at 54 mg/kg (the average level in the Morse Street group of properties), five extra cancers (above the 33,000 cancer cases from all other causes) would be expected. This is not a meaningful increase in cancer risk. Readers should refer to the American Cancer Society (www.cancer.org) or the National Cancer Institute (www.nci.nih.gov) websites for more information about cancer and its risk factors.

Moreover, the estimated arsenic dose that people would receive over 30 years is lower than the cancer effect level (CEL). The CEL is the range of doses that have caused cancer in humans and animals. The estimated arsenic dose to residents in the Morse Street Property Group is 33 times lower than the CEL for lung cancer and 100,000 times lower than the CEL for bladder cancer (ATSDR 2000). Because the dose from the site is lower than the CELs, cancer effects are unlikely. See Attachment G for the detailed dose and risk calculations.

Bryden Terrace Property Group

The second set of properties (Bryden Terrace group) consists of 39 properties. The average arsenic concentration in this group of properties is below the comparison value of 10 mg/kg. That means arsenic exposure is unlikely to be a health threat at the Bryden Terrace group of properties. In the Bryden Terrace grouping, average concentrations of six individual PAH compounds-benzo(b) fluoranthene, benzo(a)anthracene, benzo(k)fluoranthene, benzo(a)pyrene, and dibenzo(ah)anthracene-exceed comparison values. Therefore, exposure to these PAHs was evaluated further.

CT DPH calculated doses and risks from PAH exposure at the Bryden Terrace group of properties using the same assumptions described above for arsenic. Estimated PAHs doses were well below the EPA reference dose (RfD) for oral exposure to PAHs. The RfD is an estimate of the "safe dose," below which, adverse noncancer health effects are not likely. That means harmful noncancer health effects from PAH exposure are not likely. Refer to Attachment G for detailed risk calculations.

Because some PAHs are believed to cause cancer in humans, CT DPH also calculated theoretical cancer risks from exposure using the same exposure assumptions described for the arsenic cancer risk calculations. Detailed calculations are found in Attachment G. The theoretical cancer risk from PAH exposure of 8 x 10-5 (eight excess cancer cases per 100,000 exposed people) represents a non-meaningful incremental risk above the background cancer level of approximately one in three (NCI 2001). Additionally, the estimated PAH dose to residents in the Bryden Terrace Property Group is more than 200,000 times lower than PAH doses from the cancer effect levels (CELs) in the scientific literature that have been observed to cause cancer in humans and animals (ATSDR 1995). Because the dose from the site is much lower than the CELs for PAHs, cancer effects are considered very unlikely.

Pesticides and ETPH

Pesticides and extractable total petroleum hydrocarbons (ETPH) were the only other contaminants found at levels exceeding health-based comparison values in surface soil. These groups of contaminants were found at elevated levels in the samples collected from right-of-way areas adjacent to yards (see Table 1). Four pesticides (chlordane, heptachlor, beta-hexachlorocyclohexane, and dieldrin) were detected very infrequently. When average levels are calculated for these pesticides, the averages are well below health-based comparison values. The same is true for ETPH. Therefore, CT DPH concludes that health impacts from exposure to pesticides and ETPH found in soil samples in the Newhall Street neighborhood do not pose a health threat.

Health Outcome Data

CT DPH evaluated the health survey information collected from local residents by QVHD. Reported cases of cancer were verified by CT DPH in the Connecticut Tumor Registry records5 (see http://www.dph.state.ct.us/OPPE/hptumor.htm). Cancer cases occurred among individuals aged 22-85 years. Some of the cases were recently diagnosed, a few dated back to 1974. On the basis of CT DPH's review, the number and types of cancer that were reported in the health survey conducted by QVHD do not appear to be in excess of what would be expected to occur. CT DPH reached this conclusion because there was not a preponderance of cancers of the same type, or among the same age group. Different cancers are different diseases. Causes and risk factors for one type of cancer are different from another cancer. When cancer cases in a small geographic area (such as a neighborhood) are not the same type of cancer or are not within the same age group, there is little reason to believe the cancers may have a common environmental cause.

It should be emphasized that CT DPH's cancer evaluation did not include statistical analyses. Information collected in a health survey is typically not evaluated quantitatively (using statistics) because of limitations in the type of data such surveys can collect and limitations in epidemiological methods. One of the important limitations is that only about half of the targeted homes returned a completed survey form. It is not known whether there are more illnesses among the people who did not return a survey as compared with the people who did return a survey form. This limitation makes it impossible to draw any conclusions about the neighborhood as a whole. We can only say that among the Newhall Street neighborhood residents who returned a health survey form, the number and types of cancers reported do not appear to be unusual. CT DPH's cancer evaluation is contained in Attachment E.

With regard to illnesses other than cancer, from the number of dwellings surveyed (55), CT DPH believes the number and type of reported illnesses do not look unusual. Again, this evaluation was qualitative, not quantitative. Limitations in the data that can be collected using a health survey (such as the lack of background rates of illnesses) make it impossible to conclude whether the reported illnesses exceed what would be expected to occur.

CT DPH also looked at the published cancer incidence for the town of Hamden for the period 1995-1999 (CT DPH 2002). This is the period for which cancer statistics compiled by town are readily available. There were no statistically meaningful elevations in cancer incidence for Hamden during 1995-1999. It should be emphasized however, that an evaluation of townwide cancer rates is very unlikely to reveal an elevation in cancer in a particular neighborhood, unless the numbers of cancers in the neighborhood are extremely high.

2 The Hamden Middle School and the athletic field behind it are the primary areas where dumping of domestic and industrial waste occurred during the 1940s and 1950s.
3 Trigger concentrations used to indicate further sampling and the possible need for immediate action by EPA were lead concentrations in surface soil exceeding 1,200 mg/kg, arsenic exceeding 150 mg/kg or benzo(a)pyrene exceeding 10 mg/kg. Immediate actions consisted of removal of soil to a depth of approximately 18 inches and replacement with clean soil.
5 Another way for exposure to occur from groundwater is through volatilization. If volatile chemicals are present in shallow groundwater at high enough levels, chemicals can move from the groundwater to soil through vapor, which can enter basements through cracks and other openings in the foundation. Limited groundwater sampling in the neighborhood does not show the presence of volatile chemicals. More groundwater sampling is planned that should provide information needed to rule out this exposure pathway as one of concern.
6 Bioavailability refers to the degree to which lead is available to the body. Bioavailability is influenced by how easily the lead is absorbed from the soil into the body.
7 This yard (as well as other yards with very high lead levels) has already been cleaned up.
8 If someone is concerned that they might have elevated lead levels in their blood, they should contact their physician to get a blood test for lead.
9 There are many more field screening results for arsenic, but the detection limit is higher than the comparison value, so the results are not meaningful for evaluating public health impacts.
5 According to Connecticut law, all tumors diagnosed to Connecticut residents must be reported to the CT DPH Tumor Registry. The Tumor Registry has been in existence since 1935. It collects data from reporting physicians and also has an active surveillance program which reviews hospital record to ensure complete reporting of tumors.



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