Metal Contamination in On-site Soils and Sludge
HIGH QUALITY POLISHING AND PLATING
OLD ZIONSVILLE, LEHIGH COUNTY, PENNSYLVANIA
The Pennsylvania Department of Environmental Protection (PADEP) requested that the Pennsylvania Department of Health (PADOH) review analytical sampling data and determine ifresidents near the High Quality Polishing and Plating Site (the site) were exposed or couldbecome exposed to on-site metals in soils and sludge at levels that would harm their health. PADOH, working under a Cooperative Agreement with the Agency for Toxic Substances andDisease Registry (ATSDR), prepared this Health Consultation (HC) to address this issue.
The chemicals of possible health concern selected for evaluation include lead, arsenic, copper,nickel, silver, and zinc. They were detected in on-site soils and sludge (0-6 inches) at maximumconcentrations of 26,790 milligrams per kilogram (mg/kg), 58 mg/kg, 307,300 mg/kg, 8,360mg/kg, 130 mg/kg, and 156,300 mg/kg, respectively.
ATSDR and PADOH conclude that the site represents a possible future public health hazard forteenage children who may play on the site and become exposed to lead in on-site sludge if accessbecomes unrestricted or if site security (chain link fence) is routinely breached and trespassoccurs.
Direct contact with nickel, copper, or silver may cause allergic reactions in children who are veryhypersensitive to these chemicals. However, we believe this is not likely to occur given theexpected exposure scenario at the site and therefore conclude that future exposure to these otheronsite metals represents no apparent health hazard.
The interpretation, conclusions, and recommendations regarding the High Quality Polishing and Plating Site are site specific and do not necessarily apply to any other site.
The PADEP requested that PADOH review analytical sampling data and determine if residents near the High Quality Polishing and Plating Site were exposed or could become exposed to on- site metals in soils and sludge at levels that would harm their health.
Site Location and Description
The High Quality Plating Site, which is approximately 2.6 acres, is an abandoned electroplatingand polishing facility located in Upper Milford Township, Lehigh County, Pennsylvania. TheSite is along Routes 100 and 29 and approximately 3/4 mile southwest of the village of OldZionsville (Figures 1 and 2). The site consists of a large process building and two formerlagoons . The facility is currently surrounded with a chain link fence and there is no knowntrespassing occurring. It is bordered to the west by Indian Creek, to the northeast by a nursery,and then surrounding residential areas (Figure 2). Although there are no deed restrictions, it isunlikely that the site will be developed residentially because of its proximity to the creek and to the nursery.
At the request of PADEP, PADOH working under cooperative agreement with ATSDR hashistorically addressed the issue of groundwater contamination near the site [1,2].
The PADEP completed a Site Characterization Report in April 2001 . The report documents metal contamination of 38 on-site soil and sludge samples collected around the perimeter of the plant building. On August 9, 2002, boring samples (SB) were collected in soils and sludge fromdepths of 0-6" (Figure 3). Lead, arsenic, copper, nickel, silver, and zinc were detected atmaximum concentrations of 26,790 mg/kg (SB-45-sludge), 58 mg/kg (SB-40B), 307,300 mg/kg(SB-45-sludge), 8,360 mg/kg (SB-44A), 130 mg/kg (SB-45-sludge), and 156,300 mg/kg (SB-45-sludge), respectively (Table 1).
The primary concern addressed in this HC is whether teenage childrencould become exposed tometals in on-site soils and sludge at levels that would harm their health in the event that the site became unsecured in the future without appropriate remediation.
On October 15, 2001, government officials from PADOH and PADEP conducted a site visit. During the site visit, the officials observed the areas where contaminated soils and sludge arepresent. There was no evidence that children were playing onsite or that trespass was routinely occurring.
To determine the possible health effects of site-specific chemicals, ATSDR has developed health-based comparison values (CVs) that are chemical-specific concentrations to help identify environmental contaminants of health concern. We use CVs to determine which contaminants require further evaluation . These CVs include Environmental Media Evaluation Guides (EMEGs), and Reference Dose Media Evaluation Guides (RMEGs) for noncancerous health effects. If environmental media guides cannot be established because of a lack of available health data, other comparison values, such as those provided by the U.S. Environmental Protection Agency (EPA), may be used to select a contaminant for further evaluation. While media concentrations less than a CV are unlikely to pose a health threat, media concentrations above a CV do not necessarily represent a health threat. Therefore, CVs should not be used as predictors of adverse health effects or for setting cleanup levels.
PADOH also researches scientific literature and uses the ATSDR's minimal risk levels (MRLs), the EPA's reference doses (RfDs), and the EPA's Cancer Slope Factors (CSFs). MRLs are estimates of daily exposure to contaminants below which noncancerous adverse health effects are unlikely to occur. RfDs are estimates (with uncertainty spanning perhaps an order of magnitude) of daily oral exposure, in milligrams per kilogram per day (mg/kg/day), to the general public (including sensitive groups) that are likely to be without an appreciable risk of noncancerous harmful effects during a lifetime (70 years). When RfDs and MRLs are not available, a no observed adverse effect level (NOAEL) or lowest observed adverse effect level (LOAEL) may be used to estimate levels below which no adverse health effects (noncancerous) are expected.
Health guidelines such as MRLs and RfDs, however, do not consider the risk of developing cancer. To evaluate exposure to carcinogens, EPA has established CSFs for inhalation and ingestion that define the relationship between exposure doses and the likelihood of an increased risk of cancer, compared with controls that have not been exposed to the chemical. Usually derived from animal or occupational studies, CSFs are used to calculate the exposure dose likely to result in one excess cancer case per one million persons exposed over a lifetime (70 years).
Because children generally receive higher doses of contaminants than adults under similar circumstances, the PADOH uses the higher doses in forming its conclusions about the health effects of exposures to site-related contaminants when children are known or thought to be involved (see Child Health Initiative section). Also readers should note that researchers conduct animal studies using doses at levels much higher than those experienced by most people exposed to chemicals from hazardous waste sites.
In order to properly assess the human health threat associated with exposure to contaminatedsoil, it is ideal to have the shallow surface soil (0-3 inches) data. Since we do not have such data,we will use the maximum level for all chemicals of health concern in the existing data from soil boring samples (0-6 inches). It is possible that the contaminants could be diluted withuncontaminated soil as the soil sample goes deeper in the sampling process (unless the chemicalsare buried underground, as in landfills, which does not appear to be the case in this site). Therefore, the 0-6 inches of soil concentration of a specific chemical could underestimate theamount of chemical in the top 0-3 inches of surface soil. PADEP plans to remediate the site toaddress soil contamination. So rather than recommend additional sampling of 0-3 inches, wehave offset this concern by completing our evaluation using the maximum levels detected.
In this HC, we assume a worst case scenario that involves teenage children weighing 58 kg from nearby residential areas who play along side of the plant building for a total of 10 days per year for five years and who become exposed to the maximum levels of contaminants detected in on-site soils and sludge. We are assuming five years of exposure corresponding to the teenage years of 13 through 17. By age 18, we believe that it is unlikely that a teenager of this age would be playing on the site for the amount of time we are assuming for a worst case scenario and have not included this additional exposure year in our evaluation. It is also logical to assume that the exposure dose would be less for adults since we do not expect adults to be spending as much time as the children at this site. Furthermore, it is assumed that the soil ingestion rate for these children is 200 mg/day. We also assume that the property is unlikely to become residential in the future. Presently, there are no deed restrictions, however, because of its proximity to the creek (part of the site is in the 100 year flood plain), it is unlikely that a home would be built on the property.
Lead was detected adjacent to the process building in SB-45-sludge at a maximum concentrationof 26,790 mg/kg. This lead level is above the 400 mg/kg screening level used by EPA andPADEP's Act 2 non-residential direct contact level of 1,000 mg/kg.
Although lead is a concern for adults, children are particularly susceptible to adverse health effects from lead exposure. Present scientific information suggests that blood lead levels of 10 to25 micrograms per deciliter (ug/dL) may be related to delayed mental development, reduced intelligent quotient (IQ) scores, impaired hearing, and poor attention span .
To determine if the levels of lead are a concern at this site, we evaluated the potential exposure based on a recreational use scenario. As mentioned previously, we assumed that teenage children (58 kg) are on the field for a total of 10 days per year for 5 years. PADOH calculated a conservative oral reference dose estimate that corresponds to a residential exposure to 400 mg/kg of lead in soil, and using that as a screening value, compared it to potential recreational oral exposure. Dermal exposure and inhalation of fugitive dust are not likely to contribute significantly to the hazard represented by ingestion of soil.
The estimated exposure for teenage children (58 kg) under the above described scenario is 0.00253 mg/kg/day. This is about two (2) times higher than the level considered protective of public health. In addition, blood lead levels generally rise 3-7 ug/dL for every 1,000 mg/kg increases of lead in soil  . Access to soil, behavioral patterns, presence of ground cover, seasonal variation of exposure conditions, and other factors may influence this relationship. Routine exposure to high levels of lead in on-site sludge adjacent to the plant building at this site may increase the body burden substantially and may cause health problems. Therefore, the level of lead (26,790 mg/kg) in the sludge (SB-45-sludge) appears to pose a public health threat in the recreational scenario previously described. PADEP plans to remediate the site to eliminate this threat.
In general, the concentration of arsenic in soil varies widely across the United States (U.S.), ranging from about 1 to 40 mg/kg, with an average value of about 5 mg/kg . At the High Quality Polishing and Plating Site, the concentration of arsenic in on-site soils is slightly higher than the maximum concentration in U.S. soils.
Children who visit the site would be exposed to arsenic primary through ingestion. Skin contact with arsenic is not an important route of exposure because very little arsenic can enter the body through the skin .
Skin lesions appear to be the earliest observable sign of chronic exposure to arsenic . Arsenic is recognized as a human carcinogen by the U. S. Department of Health and Human Services and the World Health Organization's International Agency for Research on Cancer. The EPA also classifies arsenic as a human carcinogen.
ATSDR has developed a chronic oral Minimal Risk Level (MRL) of 0.0003 mg/kg/day for non-cancerous health effects based on epidemiologic studies that demonstrate skin lesions in people exposed to arsenic. If teenage children (58 kg) were to be exposed to arsenic in the recreational scenario described above at the maximum soil concentration (58 mg/kg), then the estimated exposure dose would be 5.48 x 10-6 mg/kg/day. This is about 55 times lower than ATSDR's chronic oral MRL. Therefore, exposure to arsenic for recreational use scenario is not likely to cause any non-cancerous adverse health effects either for children or adults.
In order to evaluate the possible cancer risk associated with ingestion of arsenic contaminated soil, we calculated the theoretical cancer risk using EPA's CSF of 1.5 (mg/kg/day) -1 for arsenic. PADOH evaluated the cancer risk associated with exposure to arsenic for 5 years at 5.87 x 10-7mg/kg/day, or a likely increase of about 6 cancers in 10,000,000 people. The cancer estimate was calculated using conservative assumptions about frequency and duration of site use previously stated. Based upon existing data, it appears that the current levels of arsenic would not pose a significant health threat for recreational use of the site. However, since arsenic is a human carcinogen, exposure to it should be eliminated or reduced to the lowest level possible.
Copper is a reddish metal that occurs naturally in rock, soil, water, sediment and air. Its average concentration in the earth's crust is about 50 mg/kg of copper in soil. Soil generally contains between 2 and 250 mg/kg of copper, although concentrations close to 7000 mg/kg have been found near copper production facilities .
ATSDR has not developed a chronic oral MRL nor EPA developed a chronic oral RfD for copper . However, the estimated oral exposure dose to copper through this environmental medium (sludge) is two (2) times lower than the established LOAEL in animal studies . Therefore, exposure to copper for the scenario described above is not likely to cause any non-cancerous adverse health effects either for children or adults. However, children who are sensitive to copper might develop allergic reactions to even a very small amount of this chemical.
Pure nickel is a hard, silvery-white metal, which has properties that make it very desirable for combining with other metals to form mixtures called alloys. Soil usually contains between 4mg/kg and 80 mg/kg of nickel in soil. One may be exposed to nickel in soil by skin contact, andchildren may also be exposed to nickel by eating soil. The most common adverse health effect ofnickel in humans is an allergic reaction to nickel .
The U.S. Department of Health and Human Services (DHHS) has determined that nickel and certain nickel compounds may reasonably be anticipated to be carcinogens. The International Agency for Research on Cancer (IARC) has determined that some nickel compounds are carcinogenic to humans and that metallic nickel may possibly be carcinogenic to humans. The EPA has determined that nickel refinery dust and nickel subsulfide are human carcinogens .
ATSDR has not developed a chronic oral MRL, but EPA has developed a Chronic Oral RfD of 0.02 mg/kg/day for non-cancerous health effects of nickel . If teenage children (58 kg) wereto be exposed to this chemical at the maximum soil concentration (8,360 mg/kg), then theestimated exposure dose would be about 25 times lower than EPA's chronic oral RfD. Therefore,exposure to nickel for the scenario described above is not likely to cause any non-cancerousadverse health effects either for children or adults. However, children who are sensitive to nickelmight develop allergic reactions to even a very small amount of this chemical.
Silver is rare but occurs naturally in the environment as a soft, "silver" colored metal. Skincontact with silver compounds has been found to cause mild allergic reactions, such as rash, swelling, and inflammation, in some people .
ATSDR has not developed a chronic oral MRL, but EPA has developed a Chronic Oral RfD of 0.005 mg/kg/day for non-cancerous health effects of silver . If the children or young adults (58 kg) were to be exposed to this chemical at the maximum soil concentration (130 mg/kg), then the estimated exposure dose would be about 6 times lower than EPA's chronic oral RfD. Therefore, exposure to silver for the scenario described above is not likely to cause any non-cancerous adverse health effects either for children or adults. However, children who are sensitive to silver might develop allergic reactions to even a very small amount of this chemical.
Zinc is found in the air, soil, and water and is present in all foods. The level of zinc in soil increases mainly from disposal of zinc wastes from metal manufacturing industries and coal ash from electric utilities. Most of the zinc in soil is bound to the soil and does not dissolve in water .
ATSDR has developed a chronic oral Minimal Risk Level (MRL) of 0.3 mg/kg/day for non-cancerous health effects . If children (58 kg) were to be exposed to zinc in the recreational scenario described above at the maximum soil concentration (156,300 mg/kg), then the estimated exposure dose would be 0.015 mg/kg/day. This is about 20 times lower than ATSDR's chronic oral MRL. Therefore, exposure to zinc in the scenario described previously is not likely to cause any non-cancerous adverse health effects either for children or adults.
ATSDR and PADOH recognize that infants and children may be more sensitive than adults when exposure to contamination in water, soil, air, or food. This sensitivity is a result of a number of factors: (1) children are more likely to be exposed to certain media (e.g., soil, sludge, sediment, air, surface water or water from springs) because they play outdoors: (2) children are shorter than adults, which means they breath dust, soil, and heavy vapors close to the ground; and (3) children are also smaller, resulting in higher doses of chemical exposure per body weight. Children can sustain permanent damage if toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care. Therefore, ATSDR and PADOH are committed to their special interests at sites such as the High Quality Polishing and Plating Site, as part of ATSDR's Child Health Initiative.
ATSDR and PADOH evaluated the likelihood that children playing on the grounds at the High Quality Plating and Polishing Site may have been or may be exposed to metals in on-site soils and sludges at levels of health concern as a result of playing on site.
PADOH and ATSDR conclude the following:
- Future exposure to lead in contaminated on-site soils and sludge represents a potential health threat and could pose a public health hazard in the event that site security was routinely breached and trespass occurred.
- Remediation of contaminated soils and sludge will ensure that the site does not become a public health hazard in the future.
- Future exposure to the other metals detected on site, at the levels evaluated in this HC, represents no apparent health hazard in the event that site security was routinely breachedand trespass occurred. Although some children may be very hypersensitive to nickel,copper or silver might develop allergic reactions to even very small amounts of thesechemicals, this is not likely to occur.
Take appropriate measures to ensure that the site is cleaned and that the public cannot come incontact with contaminated sludge in the future. PADEP has indicated that they plan to removecontaminated on-site soils and sludge and transport the material to a permitted off-site disposalfacility. PADOH supports this action and concurs that it will be protective of human health.
- Agency for Toxic Substance and Disease Registry (ATSDR). Health Consultation for theHigh Quality and Plating Site, Lehigh County, Pennsylvania, February 1997.
- Agency for Toxic Substances and Disease Registry (ATSDR). Health Consultation for theHigh Quality Site (Trichlorothene Contamination in Two Private Residential Wells nearthe High Quality Polishing and Plating Site), June 7, 2001.
- Baker Environmental, Inc., Final Site Characterization Report, High Quality Plating Site, prepared for the Pennsylvania Department of Environmental Protection (PADEP), April2001.
- Agency for Toxic Substance and Disease Registry (ATSDR). Soil/Water/Air Comparison Values and Health Guideline Comparison Values, June, 30, 2001.
- Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Lead (Update), U.S. Public Health Service. Atlanta, Georgia: ATSDR, July 1999.
- Agency for Toxic Substances and Disease Registry (ATSDR). Analysis Paper: Impact ofLead-Contaminated Soil on Public Health. U.S. Department of Health and HumanServices, Public Health Service, Atlanta, Georgia, May 1992.
- Agency for Toxic Substance and Disease Registry (ATSDR) Public Health Statement for Arsenic. April 1993. URL http://www.atsdr.cdc.gov/toxprofiles/phs2.html. November 2, 2001.
- Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Arsenic (Update), U.S. Public Health Service. Atlanta, Georgia: ATSDR, September 2000.
- Agency for Toxic Substance and Disease Registry (ATSDR) Public Health Statement for Copper. December 1990. URL http://www.atsdr.cdc.gov/toxprofiles/phs132.html.12/12/2001.
- Agency for Toxic Substance and Disease Registry (ATSDR). Toxicological Profile for Copper. December 1990. URL http://www.atsdr.cdc.gov/toxprofiles/tp132.html. 12/14/2001.
- Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Nickel (Update), U.S. Public Health Service. Atlanta, Georgia: ATSDR, September 1997.
- Agency for Toxic Substance and Disease Registry (ATSDR) Public Health Statement for Silver. December 1990. URL http://www.atsdr.cdc.gov/toxprofiles/phs146.html.12/12/2001.
- Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Zinc (Update), U.S. Public Health Service. Atlanta, Georgia: ATSDR, May 1994.
Robert M Stroman, B.S., Pharm.
Pennsylvania Department of Health
Geroncio C. Fajardo, M.D., M.B.A., M.S.
Pennsylvania Department of Health
This High Quality Polishing and Plating Site Health Consultation has been prepared by the Pennsylvania Department of Health under Cooperative Agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health consultation was initiated.
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this Health Consultation and concurs with its findings.
Richard E. Gillig
Chief, SPS, SSAB, DHAC, ATSDR
Residential PADEP ACT II Clean-Up Standard (0'-15')
Non-Residential PADEP ACT II Clean-Up Standard (0'-2')
|Lead||26,790||N/A||500||1,000||SB-45 - sludge|
|Arsenic||58||Child RMEG = 20 |
CREG** = 0.5
|Copper||307,300||N/A||8,200||190,000||SB-45 - sludge|
|Nickel||8,360||Child RMEG = 1,000||4,400||56,000||SB-44A|
|Silver||130||Child RMEG = 10 |
Adult RMEG = 300
SB-45 - sludge
|Zinc||156,300||Child RMEG = 20,000||66,000||190,000||SB-45 - sludge|
*RMEG = Reference Dose Media Evaluation Guide
**CREG = Cancer Risk Evaluation Guide for 1 x 10-6 excess cancer risk
N/A = Not Available