NCD980602163_19990816_Warren County PCB Landfill_SERB C_PCB Health Information-OCR

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POLYCHLORINATED BIPHENYLS (PCBs)
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Hazard Summary
• PCBs are a group of chemicals that contain 209 individual compounds (known as congeners) with
varying harmful effects. Information on specific congener toxicity is very limited; toxicity testing
has been done on specific commercial mixtures, whereas PCBs found in the environment will
have varied composition because ofbiotransformation or bioaccumulation .
• The U.S. Environmental Protection Agency (EPA) treats all PCBs as being potentially hazardous
based on results from some formulations. However, this can have large uncertainty for any given
mixture situation.
• No information is available on the acute (short-term) effects of PCBs in humans, and animal
studies have reported effects on the liver, kidney, and central nervous system (CNS) from oral
exposure to PCBs .
• Chronic (long-term) exposure to some PCB formulations by inhalation in humans results in
respiratory tract symptoms, gastrointestinal effects, mild liver effects, and effects on the skin
and eyes such as chloracne, skin rashes, and eye irritation.
• EPA has not established a Reference Concentration (RfC) or a Reference Dose (RID) for PCB
mixtures .
• The Reference Dose (RID) for one specific PCB mixture (Aroclor 1016) is 0.00007 mg/kg/d.a
EPA estimates that consumption of this dose or less, over a lifetime, would not likely result in the
occurrence of chronic noncancer effects.b
• EPA has not established an RfC for Aroclor 1016.
• Exposure to some PCB formulations results in developmental effects, such as motor deficits,
impaired psychomotor index, impaired visual recognition memory, and deficits in
short-term memory in infants of mothers exposed to PCBs through fish consumption.
Decreased birth weights and shortened gestational age were reported in babies born to women
occupationally exposed to high levels of PCBs. Human reproductive studies are not conclusive;
one study reports no fertility abnormalities in men occupationally exposed to PCBs, and another
reports an association between low sperm counts and elevated levels of PCBs in the blood.
• Human studies provide inconclusive, yet suggestive, evidence of an association between PCBs
exposure and liver cancer. Animal studies have reported an increase in liver tumors in rats and
mice exposed orally to some PCB formulations. EPA has classified all PCBs as Group B2,
probable human carcinogens of medium carcinogenic hazard, with a 1/ED10 value of 50 per
(mg/kg)/dc and an ingestion unit risk estimate of 2.2 x 10-4 (µ/L)-1.
a Milligrams per kilogram per day is one way to measure the amount of the contaminant that is
consumed in food.
b The RID is not a direct estimator of risk but rather a reference point to gauge the potential effects.
Exceedance of the RID does not imply that an adverse health effect would necessarily occur. As the
amount and frequency of exposures exceeding the RID increase, the probability of adverse health effects
also increases.
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c The 1/ED10 value is a measure of the carcinogenic potency of a chemical. The value reported here has
been proposed in the hazard ranking of hazardous air pollutants in EPA's proposed rulemaking (Section
l 12(g) of the Clean Air Act, April 1994).
Please Note: The main sources of information for this fact sheet are EP A's Integrated Risk Information
System (IRIS), which contains information on the carcinogenic effects of PCBs including the unit cancer
risk for oral exposure, and the Agency for Toxic Substances and Disease Registry's (ATSDR's)
Toxicological Profile for PCBs. Other secondary sources include the Hazardous Substances Data Bank
(HSDB), a database of summaries of peer-reviewed literature, and the Registry of Toxic Effects of
Chemical Substances (RTECS), a database of toxic effects that are not peer reviewed.
Environmental/Occupational Exposure
• PCBs are no longer produced in the United States and are no longer used in the manufacture of
new products; the major source of air exposure to PCBs today is the redistribution of PCBs
already present in soil and water. Smaller amounts of PCBs may be released to the air from
disposal sites containing transformers, capacitors, and other PCB wastes, incineration of
PCB-containing wastes, and improper disposal of the compounds to open areas. (1)
• PCBs have been detected in indoor air at concentrations of an order of magnitude greater than
ambient air. It has been suggested that certain electrical appliances and devices, such as
fluorescent lighting ballasts, which have PCB-containing components, may emit PCBs to the
indoor air. (1)
• In the past, PCBs were released to wastewater from its industrial uses. Today, PCBs are still
detected in water due to the environmental recycling of the compound. Most of the PCBs in water
are bound to the soil and sediments and may be released to the water slowly over a long period of
time. (1)
• PCBs have been detected in food; they bioaccumulate through the food chain, with some of the
highest concentrations found in fish. (1)
• Commercial PCB mixtures that find their way into the environment are transformed or
bioaccumulated to a different composition of PCBs. This ultimately raises uncertainty about the
relationship of toxicity tests to the toxicity of environmental samples. (2)
• PCBs have been listed as a pollutant of concern to EP A's Great Waters Program due to their
persistence in the environment, potential to bioaccumulate, and toxicity to humans and the
environment. (3)
Assessing Personal Exposure
• There are medical tests available to detect PCBs in blood, body fat, and breast milk. (1)
Health Hazard Information
Acute Effects:
• No information is available on the acute (short-term) effects of PCBs in humans. (1)
• Animal studies have reported effects on the liver, kidney, and CNS from oral exposure to PCBs.
(1)
• Acute animal tests, such as the LD50 test in rats, have shown PCBs to have moderate acute
toxicity from oral exposure. (1,4)
Chronic Effects (Noncancer):
• Chronic (long-term) exposure to PCBs by inhalation in humans has been reported to result in
respiratory tract symptoms, such as cough and tightness of the chest, gastrointestinal effects
including anorexia, weight loss, nausea, vomiting, and abdominal pain, mild liver effects, and
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effects on the skin and eyes, such as chloracne, skin rashes, and eye irritation. (1,5)
• Oral exposure to PCBs in humans has been associated with cardiovascular effects, including
hypertension, mild liver effects, and effects on the skin such as pigmentation and acne. (1,5)
• EPA has not established an RfC or an RID for mixed PCBs. (6)
• The RID for Aroclor 1016 is 0.00007 mg/kg/d based on reduced birth weights in monkeys. (7)
• EPA has medium confidence in the study on which the RID was based because this was a
well-conducted study, but only one group of monkeys was examined; medium confidence in the
database because an extensive amount of data are available but mixtures of PCBs in the
environment do not match the pattern of congeners found in Arochlor 1016; and, consequently,
medium confidence in the RID. (7)
• EPA has not established an RfC for Aroclor 1016. (7)
Reproductive/Developmental Effects:
• PCBs can reach a developing fetus (across the placenta) or be transferred to a newborn (via
mother's milk) which is a circumstance of great concern. (5)
• An epidemiological study reported that babies born to women occupationally exposed to high
levels of PCBs had lower birth weights and shortened gestational age, as compared with babies
born to women exposed to low concentrations of PCBs. (1)
• Two human studies that investigated exposure to PCBs through the consumption of contaminated
fish suggest that exposure to PCBs may cause developmental effects in humans. Both studies
reported neurodevelopmental effects, such as motor deficits at birth, impaired psychomotor index,
impaired visual recognition, and deficits in short-term memory in infants of mothers exposed to
PCBs. (1,5)
• Human studies are not conclusive on the reproductive effects of PCBs. One study of men who
were occupationally exposed to PCBs showed no fertility abnormalities, while another study of
men with low sperm counts found elevated levels of PCBs in the blood and an association
between certain PCB compounds in semen and decreased sperm motility. (1)
• Animal studies have reported developmental effects, such as learning deficits, impaired immune
functions, focal liver necrosis, and cellular alterations of the thyroid, in the offspring of animals
exposed orally to PCBs. Reproductive effects, such as decreased fertility, decreased conception,
and prolonged menstruation have also been noted in oral animal studies. (1,5)
Cancer Risk:
• Human studies provide inconclusive, yet suggestive evidence of an association between PCBs'
exposure and liver cancer. Several studies have reported an increase in liver cancer among persons
occupationally exposed to some PCB formulations. However, the studies are inconclusive due to
confounding exposures and lack of exposure quantification. (1,6)
• Oral exposure studies in animals show an increase in liver tumors in rats and mice exposed to
several commercial mixtures of PCBs and to several specific congeners. (1,6)
• No animal inhalation studies are available on PCBs. (1)
• EPA has classified all PCBs as Group B2, probable human carcinogens. (6)
• EPA uses mathematical models, based on animal studies, to estimate the probability of a person
developing cancer from ingesting water containing a specified concentration of a chemical. EPA
calculated an ingestion unit risk estimate of 2.2 x 1 o-4 (g/L )-1. EPA estimates that, if an individual
were to ingest water containing PCBs at 0.005 µ/IJ..!.l over his or her entire lifetime, that person
would theoretically have no more than a one-in-a-million increased chance of developing cancer
as a direct result of ingesting water containing this chemical. Similarly, EPA estimates that
ingesting water containing 0.05 µ/L would result in not greater than a one-in-a-hundred thousand
increased chance of developing cancer, and water containing 0.5 g/L would result in not greater
than a one-in-ten-thousand increased chance of developing cancer. However, the variation in
composition of environmental samples from commercial test mixtures raises uncertainty about the
applicability of the risk estimates. (6)
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• EPA's Office of Air Quality Planning and Standards, for a hazard ranking under Section 112(g) of
the Clean Air Act Amendments, has ranked PCBs in the nonthreshold category. The 1/ED10 value
is 50 per (mg/kg)/d and this would place it in the medium category under Superfund's ranking for
carcinogenic hazard. (8)
Physical Properties
• PCBs are a class of industrial chemical that contain 209 individual compounds. (1)
• PCBs made in the United States were marketed under the trade name Aroclor and are identified by
a four-digit numbering code in which the first two digits indicate that the parent molecule is a
biphenyl and for the 1200 series Aroclors the last two digits indicate the chlorine content by
weight. For example, Aroclor 1260 has 60 percent chlorine. (1)
• Commercial tradenames for PCBs not manufactured in the United States include Kanechlor,
Clophen, Fenclor, and Phenoclor. (1)
• PCBs are either oily liquids or solids and are colorless to light yellow in color with no known
smell or taste. (1)
• The molecular weight for one particular PCB (Aroclor 1260) is 375.7 g/mol; the vapor pressure is
4.05 x 10-5 mm Hg at 25 C; the octanol/water partition coefficient (Log K0w) is 6.8. (1)
Uses
• Before 197 4, PCBs were used in capacitors, transformers, plasticizers, surface coatings, inks,
adhesives, pesticide extenders, and carbonless duplicating paper. After 197 4, use of PCBs was
restricted to the production of capacitors and transformers, and after 1979 PCBs were no longer
used in the production of capacitors and transformers. (1)
Conversion Factors:
To convert from ppm to mg!m3: mg!m3 = (ppm) x (molecular weight of the compound)/(24.45). For
Aroclor 1260: 1 ppm = 15.4 mg!m3.
Health Data from Inhalation Exposure
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-Concentration Health
I
Regulatory, advisory numbersb I Reference
(mg/m3) numbersa
1100.0 I ll
' --
--
--
--
10.0
--• OSHA PEL and ACGIH TL V 1
--(chlorodiphenyl, 42% chlorine) (1 mg/m3) --
--
1.0
--• OSHA PEL and ACGIH TL V 1
--(chlorodiphenyl, 54% chlorine) (0.5
--mg/m3) --
0.1
--!
--
--
--
0.01
--• NIOSH REL (0.001 mg/m3) 1
--
--
--
0.001
ACGIH TLV--American Conference of Governmental and Industrial Hygienists' threshold limit value
expressed as a time-weighted average; the concentration of a substance to which most workers can be
exposed without adverse effects.
I
NIOSH REL--National Institute of Occupational Safety and Health's recommended exposure limit;
NIOSH-recommended exposure limit for an 8-or 10-h time-weighted-average exposure and/or ceiling.
OSHA PEL--Occupational Safety and Health Administration's permissible exposure limit expressed as a
time-weighted average; the concentration of a substance to which most workers can be exposed without
adverse effect averaged over a normal 8-h workday or a 40-h workweek.
a Health numbers are toxicological numbers from animal testing or risk assessment values developed by
EPA.
b Regulatory numbers are values that have been incorporated in Government regulations, while advisory
numbers are nonregulatory values provided by the Government or other groups as advice.
References
1. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Selected
PCBs. U.S. Public Health Service, U.S. Department of Health and Human Services, Altanta, GA.
1993.
2. U.S. Environmental Protection Agency. Workshop Report on Toxicity Equivalence for PCB
Congeners. EP A/625/3-91/020. 1991.
3. U.S. Environmental Protection Agency. Deposition of Air Pollutants to the Great Waters. First
Report to Congress. EPA-453/R-93-055. Office of Air Quality Planning and Standards, Research
Triangle Park, NC. 1994.
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4. U.S. Department of Health and Human Services. Registry of Toxic Effects of Chemical
Substances (RTECS, online database). National Toxicology Information Program, National
Library of Medicine, Bethesda, MD. 1993.
5. U.S. Department of Health and Human Services. Hazardous Substances Data Bank (HSDB, online
database). National Toxicology Information Program, National Library of Medicine, Bethesda,
MD. 1993.
6. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on PCBs.
Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment,
Office of Research and Development, Cincinnati, OH. 1994.
7. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on Aroclor
1016. Environmental Criteria and Assessment Office, Office of Health and Environmental
Assessment, Office of Research and Development, Cincinnati, OH. 1994.
8. U.S. Environmental Protection Agency. Technical Background Document to Support Rulemaking
Pursuant to the Clean Air Act--Section 112(g). Ranking of Pollutants with Respect to Hazard to
Human Health. EPA-450/3-92-010. Emissions Standards Division, Office of Air Quality Planning
and Standards, Research Triangle Park, NC. 1994.
1. *Micrograms per liter is the unit of measurement for chemicals in water.
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