PUBLIC HEALTH ASSESSMENT
FALCON REFINERY
INGLESIDE, SAN PATRICIO COUNTY, TEXAS
SUMMARY AND STATEMENT OF ISSUES
The Falcon Refinery site is located at the intersection of Farm to Market Road 2725 and Bishop Road, Ingleside, San Patricio County, Texas. The site, which is an abandoned refinery that has operated intermittently since 1980, encompasses 104 acres and is approximately 18 miles northeast of the city of Corpus Christi. The refinery used crude oil to produce naphtha, kerosene, jet fuel, diesel, and fuel oil. Peak operating capacity was approximately 40,000 barrels of product a day.
In November 2000, the Texas Commission on Environmental Quality (TCEQ), formerly the Texas Natural Resource Conservation Commission (TNRCC), completed an Expanded Site Inspection (ESI) report of the site. The ESI findings indicated that chemical releases from the facility have affected sediments in Redfish Bay, sediments in the on-site wetlands, and the on-site soils. The Falcon Refinery site was proposed to the National Priorities List (NPL) on September 5, 2002. The NPL is used by the U.S. Environmental Protection Agency (EPA) to determine which sites justify further investigation in order to assess the nature and extent of health and environmental risks associated with the release of hazardous substances.
The Texas Department of Health (TDH) and the Agency for Toxic Substances and Disease
Registry (ATSDR) reviewed the environmental information available for the site. Exposure
pathways through which the public might possibly come into contact with contaminants from
the site were evaluated. These exposure pathways included air, groundwater, surface water,
soil, sediment, and biota 
(food chain). Based on the available information, the Falcon Refinery
site poses an indeterminate public health hazard. If in the future, site conditions change, a re-evaluation of the public health significance of this site would be necessary.
The Agency for Toxic Substances and Disease Registry (ATSDR) was established under the mandate of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980. This act, also known as the "Superfund" law, authorized the U.S. Environmental Protection Agency (EPA) to conduct clean-up activities at hazardous waste sites. EPA was directed to compile a list of sites considered hazardous to the public health. This list is termed the National Priorities List (NPL). The 1986 Superfund Amendments and Reauthorization Act (SARA) directed ATSDR to prepare a Public Health Assessment (PHA) for each NPL site. In 1990, federal facilities were included on the NPL. (Note: Appendix A provides a listing of abbreviations and acronyms used in this report.)
In conducting the PHA, three types of information are used: environmental data, community health concerns and health outcome data. The environmental data are reviewed to determine whether people in the community might be exposed to hazardous materials from the NPL facility. If people are being exposed to these chemicals, ATSDR will determine whether the exposure is at levels that might cause harm. Community health concerns are collected to determine whether health concerns expressed by community members could be related to exposure to chemicals released from the facility. If the community raises concerns about specific diseases in the community, health outcome data (information from state and local databases or health care providers) can be used to address the community concerns. Also, if ATSDR finds that harmful exposures have occurred, health outcome data can be used to determine if illnesses are occurring which could be associated with the hazardous chemicals released from the NPL facility.
In accordance with the Interagency Cooperative Agreement between ATSDR and the Texas Department of Health (TDH), this PHA was prepared for the Falcon Refinery site. This PHA presents conclusions about whether exposures are occurring, and whether a health threat is present. In some cases, it is possible to determine whether exposures occurred in the past; however, often a lack of appropriate historical data makes it difficult to quantify past exposures. If it is found that a threat to public health exists, recommendations are made to stop or reduce the threat to public health.
The Falcon Refinery is an approximately 104-acre site located at the intersection of Farm to Market Road 2725 and Bishop Road in Ingleside, San Patricio County, Texas. The site is approximately 18 miles northeast of the city of Corpus Christi [1]. Wetlands lie to the northeast and southeast of the site. Commercial businesses are adjacent to the site and the nearest residential area is approximately 0.2 mile northwest of the site. The Gulf of Mexico is approximately 8 miles east of the site.
Falcon Refinery operated intermittently beginning in 1980 and is currently inactive. The facility refined crude oil into naphtha, jet fuel, kerosene, diesel, and fuel oil. During peak operating capacity, the facility could produce up to 40,000 barrels of product per day. At a nearby dock located on the Intracoastal Waterway, crude oil and refined product were transferred between barges and the facility's storage tanks.
Complaints by residents began in 1978 with the construction of the facility and in 1985-86 because
of odors allegedly produced from the processing of impure crude. Regulatory inspections, conducted
periodically in response to complaints, indicate operational problems. In 1980, approximately 3
cubic yards of separator sludge were spread on the ground. In 1985, the refinery's wastewater
treatment system was inoperable during the processing of 100,000 barrels of slop oil. In 1986, an
inspection by the Texas Water Commission revealed cooling tower sludge had been disposed of on-site and untreated wastewater had been discharged into unlined pits. In 1987, an EPA site inspection
indicated there was a breech in the dike surrounding some source areas and run-off may have flowed
into the wetlands. In 1995, a spill occurred as a result of pipeline testing. In 1996, an inspection
conducted in response to an alleged pipeline spill indicated benzene was dumped. A leak from a
tank in the naphtha stabilizer unit was observed in January 2000. As a result of that leak, the
TNRCC and EPA performed sampling of the site in May 2000 and identified five sources of
contamination [2].
Source 1: soil (associated with bermed areas around storage tanks #10, 11, 26, and 27)
Source 2: soil (dump area)
Source 3: soil (storage tanks associated with the main facility)
Source 4: soil (land treatment basin)
Source 5: soil (associated with dumped cooling tower sludge)
Containment berms and/or liners were absent in some source areas. Run-on/run-off management systems in some source areas were either absent or not maintained. The Falcon Refinery site was proposed to the National Priorities List on September 5, 2002.
Land Use and Natural Resource Use
The site, located in the San Antonio-Nueces Coastal basin, receives an average rainfall amount of 35 inches per year. At approximately 5 feet above sea level, the site is located in a 100-year flood plain [2]. Land usage adjacent to the site is industrial, commercial, and residential. The site gradually slopes towards the southeast and drains into the facility's on-site wetlands. The southern and eastern portion of the site consists of wetlands and estuarine type land. Drainage from the site eventually flows into Redfish Bay then into the Gulf of Mexico.
TDH personnel visited the site on April 23, 2003. Approximately four hours were spent examining the site and visiting with the surrounding residents and commercial businesses. There was no evidence of recent rainfall, runoff or erosion. All roadways on the site are located near the storage tanks and are composed of concrete, asphalt, and dirt. Berms, which appeared to be intact, surrounded all the storage tanks and were overgrown with grass. TDH noticed past chemical spillage had stained plant growth around one of the storage tanks. Odors associated with the spillage were noted. The land not in use is sandy with low lying grasses and some cactus.
The site is fenced, however a section of fence along Bishop Road, was down on the ground. The front gate area was open at the time of the visit. Tanker trucks were entering the site to receive fuel from storage tanks located near the front gate. "No Trespassing" signs were posted at the front gate. There was no indication of trespassing at the time of the site visit.
The 2000 San Patricio County census data reports a total population of 9,388 for the city of Ingleside and a county population of 67,138 residents [3]. The 2000 U.S. Census Bureau data reports a total population of 423 people and 175 housing units within 1 mile of the site [Figure 1]. The nearest occupied residence is approximately 0.2 mile northwest of the site in the 1200 block of Bishop Road.
In an attempt to determine community health concerns related to the Falcon Refinery site, TDH went door to door and contacted businesses and residents near the site. No community health concerns specific to the Falcon Refinery site were identified; however some individuals reported occasional petrochemical odors emanating from the storage tanks.
Health outcome data (HOD) record certain health conditions that occur in populations. These data can provide information on the general health of communities living near a hazardous waste site. They also can provide information on patterns of specified health conditions. Some examples of health outcome databases are tumor registries, birth defects registries, and vital statistics. Information from local hospitals and other health care providers also can be used to investigate patterns of disease in a specific population. TDH and ATSDR look at appropriate and available health outcome data when a completed exposure pathway or community concern exists. Because no completed exposure pathways and no identified community health concerns exist, a review of HOD was not conducted for this site.
DISCUSSION (ENVIRONMENTAL CONTAMINATION, PATHWAY ANALYSIS, AND PUBLIC HEALTH IMPLICATIONS)
The presence of chemical contaminants in the environment does not always result in exposure to or contact with the chemicals. Because chemicals have the potential to cause adverse health effects only when people actually come into contact with them, it is exposure (the contact that people have with the contaminants) that drives the PHA process.
People can be exposed to contaminants by breathing, eating, drinking, or coming into direct contact with a substance containing the contaminant. This section reviews available information to determine whether people in the community have been, currently are, or could in the future be exposed to contaminants associated with this site.
To determine whether people are exposed to site-related contaminants, investigators evaluate the environmental and human components leading to human exposure. This analysis consists of evaluating the five elements of an exposure pathway:
Exposure pathways can be complete, potential, or eliminated. For a person to be exposed to a contaminant, the exposure pathway must be complete. An exposure pathway is considered complete when all five elements in the pathway are present and exposure has occurred, is occurring, or will occur in the future. A potential pathway is missing at least one of the five elements but could be complete in the future. An eliminated pathway is missing one or more elements and will never be completed. Table 1 identifies pathways important to this site. The following discussion incorporates only those pathways relevant and important to the site.
Because exposure does not always result in adverse health effects, an evaluation
of whether the exposure could be sufficient to pose a hazard to people in the
community also is done. The factors that influence whether exposure to a contaminant
or contaminants could or would result in adverse health effects include:
(1) the toxicological properties of the contaminant; (2) how much of the contaminant
the individual is exposed to; (3) how often and/or how long the exposure occurs;
(4) the manner in which the contaminant enters or contacts the body (breathing,
eating, drinking, or skin/eye contact); and (5) the number of contaminants to
which an individual is exposed (combinations of contaminants).
Once exposure occurs, characteristics such as age, sex, nutritional status, genetics, lifestyle, and health status of the exposed person influence how that person absorbs, distributes, metabolizes, and excretes the contaminant.
When identifying plausible potential exposure scenarios, the first step is assessing the potential public health significance of the exposure. This is done by comparing contaminant concentrations to health assessment comparison (HAC) values for both noncarcinogenic and carcinogenic end points. HAC values are media-specific contaminant concentrations used to screen contaminants for further evaluation. Although exceeding a HAC value does not necessarily mean that a contaminant represents a public health threat, it does suggest that the contaminant warrants further consideration.
Noncancer comparison values are also known as environmental media evaluation guides (EMEGs) or reference dose media evaluation guides (RMEGs) and are based on ATSDR's minimal risk levels (MRLs) and EPA's reference doses (RfDs), respectively. MRLs and RfDs are estimates of daily human exposure to a contaminant that is unlikely to cause adverse noncancer health effects over a lifetime. Cancer risk comparison values are also known as carcinogenic risk evaluation guides (CREGs) and are based on EPA's chemical-specific cancer slope factors and an estimated excess lifetime cancer risk of 1-in-1-million persons exposed for a lifetime. Standard assumptions are used to calculate appropriate HAC values [4].
The environmental data used in this PHA were obtained from soil and sediment sampling conducted by the TNRCC in May 2000 for their Expanded Site Inspection (ESI) Report [5]. The samples were analyzed for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), polychlorinated biphenyls (PCBs), pesticides, and metals. In reviewing the sampling data, the information provided in the referenced documents was relied upon and it was assumed that adequate Quality Assurance/Quality Control (QA/QC) measures were followed with regard to chain-of-custody, laboratory procedures, and data reporting.
Air
Summary: Air sampling data and historical air releases from the Falcon Refinery site were not available for review. Because of the lack of information available for this pathway, we have concluded that past and current exposure to contaminants in the air at this site pose an indeterminate public health hazard.
Air sampling data from historical air releases from the Falcon Refinery site were not available for review. Volatilization of chemicals at the site from storage tanks, chemical overflows and spills likely occurred during operations. The potentially exposed population would have consisted of on-site workers and people working in the surrounding businesses and living in the neighborhood. The EPA Remedial Investigation and Feasibility Study, planned for a future date, will determine the volume of wastes remaining on-site [1]. During the site visit, chemical odors were noted.
Until further sampling or removal of the remaining chemical wastes, current exposure to contaminants in the air cannot be assessed. Because of the lack of historical and current air sampling data, we have concluded that exposure to contaminants in the air pose an indeterminate public health hazard.
Groundwater
Summary: Groundwater in the vicinity of the site is not currently used as drinking water. Potable water is supplied to area residents and businesses from an approved surface water source. Groundwater sampling data from the site and surrounding areas were not available for review. Past and current exposures to contaminants in the groundwater at this site pose an indeterminate public health hazard.
Groundwater in the vicinity of the site has been used for drinking, food preparation, and bathing. Since 1999, the City of Aransas Pass has supplied potable water from the Nueces River to the residents and businesses surrounding the site. The raw water intakes for the water supply system are located approximately 30 miles west of the Falcon Refinery site [6].
The nearest residential population is northwest of the Falcon Refinery site on Bishop Road. The residential water wells on Bishop Road vary from approximately 45 to 65 feet in depth. All residents contacted by TDH, with one exception, currently use their water wells for landscaping purposes only. One family uses its well for household cleaning purposes, not for food preparation or ingestion. It is not known if the well water is used for showering or bathing. According to the homeowner, the well has been in use since 1959 and the family purchases bottled water. The homeowner stated his family is not financially able to connect with the city water supply.
Groundwater sampling data from the Falcon Refinery site and surrounding areas were not available for review. The Hazard Ranking System (HRS) Documentation Record states, "… groundwater was impacted by the January 4, 2000 spill from the naphtha stabilizer unit …" [2]. The public health significance of past exposure through the groundwater could not be assessed. Because of the lack of historical and current sampling data, we have concluded that past and present exposure to the groundwater poses an indeterminate public health hazard.
Surface Water
Summary: Sediment sampling results indicate that hazardous substances identified at the Falcon Refinery site have migrated from the site via the surface water pathway. Surface water sampling data were not available for review. Past and current exposures to contaminants in the surface water at this site pose an indeterminate public health hazard.
The HRS report indicates sediment samples collected from Redfish Bay and the on-site wetlands reveal hazardous substances have migrated from the site via the surface water pathway. Surface water drainage enters the site along the southeastern section of the site and enters the on-site wetlands. A culvert connects the on-site wetlands, travels to off-site wetlands, and then into Redfish Bay (Intracoastal Waterway).
Access to the site and surrounding wetlands is limited. While fishing does occur in Redfish Bay, actual exposure to surface water contaminants through dermal contact or incidental ingestion during this activity would be limited. It is unlikely that people would be exposed to contaminants often enough to be a health concern. Because of the lack of sampling data, we have concluded that past and present exposure to contaminants in the surface water pose an indeterminate public health hazard.
Surface Soil
Summary: Exposure to contaminants in the surface soil at this site would not be expected to result in adverse health effects. Although access to the site is somewhat restricted, we do not consider exposure to contaminants in the soil either through ingestion or dermal contact to be a significant exposure pathway since: 1) the probability of regularly ingesting contaminated soil is low; 2) the frequency and duration of any contact with contaminated soil would likely be low, and; 3) the surface area of skin likely to come into regular contact with the contaminated soil is likely to be small. The surface soil pathway is expected to pose no apparent public health hazard.
Soil samples were collected from 0 to 6 inches in depth during the May 2000 sampling event. Analysis indicated arsenic and benzo(a)pyrene exceeded their respective HAC values (Table 2). Arsenic and benzo(a)pyrene levels were highest in sample SO-28. This sample was collected from a mound located near the southwest corner of the main facility.
Arsenic exceeded its CREG value of 0.5 mg/kg (milligrams per kilogram) in eighteen samples. Only one sample exceeded the non-cancer HAC value for children. The highest arsenic level was 23.3 mg/kg. It is important to point out, with the exception of sample SO-28, the concentration of arsenic collected from the site is similar to or less than the average concentration of 5.5 mg/kg reported for the western United States [7]. Benzo(a)pyrene exceeded its CREG value of 0.1 mg/kg in three samples. The highest result was 1.6 mg/kg.
Access to the site is somewhat restricted and the exposed population would consist of on-site workers and trespassers. Actual exposure to contaminants through dermal contact or incidental ingestion during these activities would be limited. Since it is unlikely that people would be exposed to contaminants often enough at sufficient concentrations to be a health concern, exposure to the surface soil at the Falcon Refinery site would be expected to pose no apparent public health hazard.
Sediment
Summary: Exposure to contaminants in the sediment at this site would not be expected to result in adverse health effects. Although access to the site is somewhat restricted, we do not consider exposure to contaminants in the sediment either through ingestion or dermal contact to be a significant exposure pathway since: 1) the probability of regularly ingesting contaminated sediment is low; 2) the frequency and duration of any contact with contaminated sediment would likely be low, and; 3) the surface area of skin likely to come into regular contact with the contaminated sediment is likely to be small. The sediment pathway is expected to pose no apparent public health hazard.
Sediment samples were collected from on-site/off-site wetlands and in the Intracoastal Waterway (Redfish Bay). Sample depths ranged from 0 to 30 inches.
Arsenic exceeded its CREG value of 0.5 mg/kg in twenty-five samples. The highest result was 4.4 mg/kg (Table 3). This sample, SE-12, was collected from off-site wetlands located north of Sunray Road. Benzo(a)pyrene exceeded its CREG value of 0.1 mg/kg in three samples. Sample SE-30 contained the highest level at 3.7 mg/kg. This sample was collected near the site's loading dock facility on Redfish Bay.
The loading dock facility is an industrial area with restricted access. The exposed population would be limited to on-site workers and trespassers that may come into contact with sediments. Actual exposure to the contaminant through dermal contact or incidental ingestion would be limited. Since it is unlikely that people would be exposed to contaminants often enough at sufficient concentrations to be a health concern, exposure to sediment at the Falcon Refinery site would be expected to pose no apparent public health hazard.
Biota (Seafood)
Summary: Biota (seafood) sampling data for Redfish Bay were not available for review. Finfish and shellfish sampling has occurred in water bodies adjacent to the bay. Redfish Bay is used by the public for recreational fishing; however, with the lack of sampling data, past and current exposure to contaminants in the biota at this site pose an indeterminate public health hazard.
The Texas Department of Health Seafood Safety Division periodically collects fish and shellfish samples from coastal waters and the Gulf of Mexico. No finfish or shellfish chemical data for Redfish Bay were available for review. The TDH has placed a restriction on the harvesting of shellfish (oysters, clams, and mussels) from Redfish Bay. The current TDH restriction became effective on November 1, 2003 [8]. This restriction is due to the lack of manpower to enforce shellfish regulations, which is provided by the Texas Parks and Wildlife Department [9].
Because of the lack of historical and current sampling data for Redfish Bay, we have concluded that past and present exposure to contaminants in the biota (seafood) pose an indeterminate public health hazard.
CHILDREN'S HEALTH CONSIDERATIONS
ATSDR recognizes that the unique vulnerabilities of infants and children demand special emphasis in communities faced with contamination of their water, soil, air, or food. Children are at greater risk than are adults from certain kinds of exposures to hazardous substances emitted from waste sites and emergency events. They are more likely to be exposed because they play outdoors and they often bring food into contaminated areas. They are shorter than adults, which means they breathe dust, soil, and heavy vapors close to 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 during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decision, and access to medical care.
ATSDR evaluated the likelihood for children living in the vicinity of the Falcon Refinery site to be exposed to site contaminants at levels of health concern. Children currently are not likely to be exposed to contaminants from the site. Access to the site by children is unlikely because of the distance from residential areas and the limited accessibility to the property. Abandoned equipment and machinery could pose a physical hazard to small children if they were to trespass on the site; however, the plausibility that this will occur is low.
AUTHORS, TECHNICAL ADVISORS, AND ORGANIZATIONS
Report Prepared by
Tom Ellerbee
Environmental Specialist
Environmental Epidemiology and Toxicology Division
Tina Walker, EMT
Information Specialist
Environmental Epidemiology and Toxicology Division
John F. Villanacci, PhD, EMT
Director
Environmental Epidemiology and Toxicology Division
George Pettigrew, PE
Senior Regional Representative
ATSDR Region 6
Robert Knowles, MS, REHS
Environmental Health Scientist
Division of Health Assessment and Consultation
Superfund Site Assessment Branch
State Programs Section
This public health assessment was prepared by the Texas Department of Health under a 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 public health assessment was initiated.
Robert Knowles
Technical Project Officer, SPS, SSAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this Public Health Assessment and concurs with its findings.
Roberta Erlwein
Chief, State Programs Section, SSAB, DHAC, ATSDR
. August 4, 2003.. August 2003.APPENDIX A: ACRONYMS AND ABBREVIATIONS
| ATSDR | Agency for Toxic Substances and Disease Registry |
| CERCLA | Comprehensive Environmental Response, Compensation and Liability Act of 1980 |
| CREG | Cancer Risk Evaluation Guide |
| EMEG | Environmental Media Evaluation Guide |
| EPA | Environmental Protection Agency |
| ESI | Expanded Site Inspection |
| HAC | Health Assessment Comparison Value |
| HOD | Health Outcome Data |
| HRS | Hazard Ranking System |
| MRL | Minimal Risk Level |
| NPL | National Priorities List |
| PCBs | Polychlorinated Biphenyls |
| PHA | Public Health Assessment |
| QA/QC | Quality Assurance/Quality Control |
| RfD | Reference Dose |
| RMEG | Reference Dose Media Evaluation Guide |
| SARA | Superfund Amendments and Reauthorization Act of 1986 |
| SVOCs | Semi-Volatile Organic Compounds |
| TCEQ | Texas Commission on Environmental Quality |
| TDH | Texas Department of Health |
| TNRCC | Texas Natural Resource Conservation Commission |
| VOCs | Volatile Organic Compounds |
Table 1. Evaluation of Potential Exposure Pathways for Falcon Refinery
| Pathway Name | Contaminants of Concern | EXPOSURE PATHWAY ELEMENTS | Time | Conclusions | ||||
| Source | Transport Media | Point of Exposure | Route Of Exposure | Exposed Population | ||||
| Air (incomplete) |
no data | site operations, spills |
air | on-site, off-site |
inhalation | area residents, workers, trespassers |
past present future |
Indeterminate public health hazard; due to the lack of sampling data. |
| Groundwater (incomplete) |
no data | site operations, spills |
groundwater | on-site, off-site |
dermal contact, incidental ingestion |
area residents and workers using well water | past present future |
Indeterminate public health hazard; due to the lack of sampling data. |
| Surface Water (incomplete) |
no data | site operations, spills |
surface water | on-site wetlands, off-site wetlands, Redfish Bay |
dermal contact, incidental ingestion |
workers, trespassers, off-site fishermen |
past present future |
Indeterminate public health hazard; due to the lack of sampling data. |
| Surface Soil (potential) |
arsenic, benzo(a)pyrene |
site operations, spills |
soil | on-site | dermal contact, incidental ingestion |
workers, trespassers |
past present future |
No apparent public health hazard; sufficient evidence indicates that people would not be exposed to potential contaminants in the surface soil at sufficient concentrations and often enough to present a health concern. |
| Sediment (potential) |
arsenic, benzo(a)pyrene |
site operations, spills, surface water migration |
surface water | off-site | dermal contact, incidental ingestion |
workers, trespassers |
past present future |
No apparent public health hazard; sufficient evidence indicates that people would not be exposed to potential contaminants in the sediment at sufficient concentrations and often enough to present a health concern. |
| Biota/seafood (incomplete) |
no data | surface water migration from site operations, spills |
finfish shellfish |
off-site fishing | ingestion | off-site fishermen | past present future |
Indeterminate public health hazard; due to the lack of sampling data. |
Table 2. Soil Samples: Constituents exceeding
Health Assessment Comparison (HAC) values
| Constituent | HAC Value | # samples HAC value per total # of samples | Range (mg/kg) |
| Arsenic | 0.5 CREG 20 child / 200adult - chronic EMEG & RMEG |
18/33 | n.d. - 23.3 |
| Benzo(a)pyrene | 0.1 CREG | 3/26 | n.d. - 1.6 LJ |
Table 3. Sediment Samples: Constituents
exceeding Health Assessment Comparison (HAC) values
| Constituent | HAC Value | # samples HAC value per total # of samples | Range (mg/kg) |
| Arsenic | 0.5 CREG 20 child / 200adult - chronic EMEG & RMEG |
25/33 | n.d. - 4.4 J^ |
| Benzo(a)pyrene | 0.1 CREG | 3/33 | n.d. - 3.7 |
CREG = Cancer Risk Evaluation Guide. Based on an excess cancer
risk of 1 in 1 million persons exposed over a lifetime.
EMEG = Environmental Media Evaluation Guide
L = reported concentration is between the IDL (instrument detection limit) and
the CRDL (contract required detection limit)
J = estimated concentration
mg/kg = milligrams per kilogram
n.d. = not detected
RMEG = Reference Dose Media Evaluation Guide
^ = actual concentration may be lower than the concentration reported
