DEQ-CFW_00001982

PFOA Site -Specific Action Level in West Virginia (near Dupont's Washington Works facility)
Background
On November 20, 2006, the National Enforcement Investigations Center of the US EPA signed an
agreement with DuPont establishing a site -specific action level for PFOA in drinking water sources
near the DuPont Washington Works facility, located in Parkersburg, West Virginia. This agreement,
termed a "consent order" states that DuPont must offer alternative drinking water or treatment for
public water or private water users living near the facility if the level of PFOA detected in drinking
water is equal to or greater than 0.5 ppb (µg/L .
This level of 0.5 ppb replaces the level of 150 ppb that was part of a 2002 consent order between EPA
and DuPont. The reasons given by EPA for lowering the site -specific action level are:
1. Recent studies show that people who live in the vicinity of DuPont's Washington Work's plant
have a median PFOA level of 298 to 369 ppb in their blood. This level is much higher than the
median level of 5 ppb found in the general U.S. population.
2. Newer studies have demonstrated various kinds of toxic effects on experimental animals, and
the results are of concern to public health.
Basis for Number
• Based on 2002 study where monkeys were given APFO in oral capsules for 26 weeks at 0, 3,
10, and 30 mg/kg-day. Increased liver weights were seen at 3 mg/kg-day, which was used as
the lowest -observed -adverse -effect level (LOAEL).
• An uncertainty factor (UF) of 13,500 was applied, based on: a 10-fold factor for extrapolation
from a LOAEL to a no -observed -adverse -effect level (NOAEL); a 10-fold factor for
intraspecies variability; and a 135-fold factor for interspecies variability [3 for toxicodynamics
x 45 months/1 month] (clearance in humans)/clearance in monkeys).
• A relative source contribution (RSC) factor of 20% was used, based on EPA's typical estimate
that 20% of exposure is derived from drinking water.
• A body weight (BW) of 10 kg was used based on the typical body weight of a child.
• An ingestion rate (IR) of 0.85 liters/day was used based on the typical amount of water ingested
per day by a child.
Recommended Site -specific Action Level for Drinking Water = LOAEL x BW x RSC =
OF x IR
3 mg/kg-day x 10 kg x 0.2 = 0.5 µg/L (ppb)
13,500 x 0.85 L/day
DEQ-CFW 00001982

NC IMAC for PFOA
Basis for Number
• Based on a 2004 two -generation reproductive study in rats where rats were given 0, 1, 3, 10,
and 30 mg/kg-day APFO and increased liver weight and reduction in body weight gain was
seen at 1 mg/kg-day. 1 mg/kg-day was used as the LOAEL.
• Uncertainty factor (UF) of 3,000 was used based on a 10-fold factor for intraspecies variability;
a 10-fold factor for interspecies variability; a 10-fold factor for LOAEL to NOAEL
extrapolation, and a 3-fold factor for database gaps on the toxicity of PFOA.
• A relative source contribution (RSC) factor of 20% was used, based on EPA's typical estimate
that 20% of exposure is derived from drinking water.
• A body weight (BW) of 70 kg was used, based on the typical body weight of an adult.
• An ingestion rate (IR) of 2 liters of water per day was used, based on the typical amount of
water ingested per day by an adult.
NC IMAC = LOAEL x BW x RSC = 1 m /g/kg-day x 70 kg x 0.2 = 2.1 µg/L = 2 ppb
OF x IR 3,000 x 2 L/day
Reasons for using 2 ppb instead of 0.5 ppb as NC's IMAC for PFOA
1. LOAEL: EPA guidance calls for the use of the lowest LOAEL or NOAEL available from all
the available studies. 1 mg/kg-day from the 2004 study is lower than 3 mg/kg-day from the
2002 study.
2. Uncertgply factor: EPA guidance recommends limiting the total OF to no more than 3,000
(EPA, 2002, A Review of the Reference Dose and Reference Concentration Processes,
EPA/630/P-02/002F, p.4-41). The use of a OF of 13,500 is not in accordance with this
guidance.
3. Child vs. adult body weight and ingestion rate: NC 2L rules mandate the use of a 70 kg body
weight and an ingestion rate of 2 liters of water per day in the calculation of a systemic
threshold concentration. If the child body weight and ingestion rate were used to calculate the
IMAC, this would have to be changed to an adult body weight and ingestion rate when
calculating the 2L number.
4. Site -specific number: EPA specifically calculated their number for people who live in the
vicinity of the Washington Works facility, where the average concentration of PFOA in the
blood was measured at 298 to 369 ppb. According to the Washington, West Virginia facility
reports, the emissions in 1999 — 2000 timeframe were 31,000 lbs in air and 56,000 lbs in water
-- this WV facility has significantly reduced emissions in the last few years to 2001bs in air
and 15001bs in the water(reported in 2004). To compare the basic exposure of NC citizens ,
"Biennial Report for APFO Manufacture" for Calendar Years of 2004 and 2005 reported to the
US EPA for the Dupont Fayetteville Works Site in Bladen County, North Carolina indicates
an air emission rate of 55.5 lbs in air and <1.61bs in water.
DEQ-CFW 00001983

PFOA Site -Specific Action Level in West Virginia (near Dupont's Washington Works facility)
Background
On November 20, 2006, EPA signed an agreement with DuPont establishing a site -specific action level
for PFOA in drinking water sources near the DuPont Washington Works facility, located in
Parkersburg, West Virginia. This agreement, termed a "consent order" states that DuPont must offer
alternative drinking water or treatment for public water or private water users living near the facility if
the level of PFOA detected in drinking water is equal to or greater than 0.5 ppb (µgLQ.
This level of 0.5 ppb replaces the level of 150 ppb that was part of a 2002 consent order between EPA
and DuPont. The reasons given by EPA for lowering the site -specific action level are:
1. Recent studies show that people who live in the vicinity of DuPont's Washington Work's plant
have a median PFOA level of 298 to 369 ppb in their blood. This level is much higher than the
median level of 5 ppb found in the general U.S. population.
2. Newer studies have demonstrated various kinds of toxic effects on experimental animals, and
the results are of concern to public health.
Basis for Number
• Based on 2002 study where monkeys were given APFO in oral capsules for 26 weeks at 0, 3,
10, and 30 mg/kg-day. Increased liver weights were seen at 3 mg/kg-day, which was used as
the lowest -observed -adverse -effect level (LOAEL).
• An uncertainty factor (UF) of 13,500 was applied, based on: a 10-fold factor for extrapolation
from a LOAEL to a no -observed -adverse -effect level (NOAEL); a 10-fold factor for
intraspecies variability; and a 135-fold factor for interspecies variability [3 for toxicodynamics
x 45 months/1 month] (clearance in humans)/clearance in monkeys).
• A relative source contribution (RSC) factor of 20% was used, based on EPA's typical estimate
that 20% of exposure is derived from drinking water.
• A body weight (BW) of 10 kg was used based on the typical body weight of a child.
• An ingestion rate (IR) of 0.85 liters/day was used based on the typical amount of water ingested
per day by a child.
Recommended Site -specific Action Level for Drinking Water = LOAEL x BW x RSC =
OF x IR
3 mg/kg-day x 10 kg x 0.2 = 0.5 µg/L (ppb)
13,500 x 0.85 L/day
DEQ-CFW 00001984

NC IMAC for PFOA
Basis for Number
• Based on a 2004 two -generation reproductive study in rats where rats were given 0, 1, 3, 10,
and 30 mg/kg-day APFO and increased liver weight and reduction in body weight gain was
seen at 1 mg/kg-day. 1 mg/kg-day was used as the LOAEL.
• Uncertainty factor (UF) of 3,000 was used based on a 10-fold factor for intraspecies variability;
a 10-fold factor for interspecies variability; a 10-fold factor for LOAEL to NOAEL
extrapolation, and a 3-fold factor for database gaps on the toxicity of PFOA.
• A relative source contribution (RSC) factor of 20% was used, based on EPA's typical estimate
that 20% of exposure is derived from drinking water.
• A body weight (BW) of 70 kg was used, based on the typical body weight of an adult.
• An ingestion rate (IR) of 2 liters of water per day was used, based on the typical amount of
water ingested per day by an adult.
NC IMAC = LOAEL x BW x RSC = 1 m /g_kg-day x 70 kg x 0.2 = 2.1 µg/L = 2 ppb
OF x IR 3,000 x 2 L/day
Reasons for using_2 ppb instead of 0.5 ppb as NC's IMAC for PFOA
1. LOAEL: EPA guidance calls for the use of the lowest LOAEL or NOAEL available from all
the available studies. 1 mg/kg-day from the 2004 study is lower than 3 mg/kg-day from the
2002 study.
2. Uncertainty factor: EPA guidance recommends limiting the total OF to no more than 3,000
(EPA, 2002, A Review of the Reference Dose and Reference Concentration Processes,
EPA/630/P-02/002F, p.4-41). The use of a OF of 13,500 is not in accordance with this
guidance.
3. Child vs. adult body weight and ingestion rate: NC 2L rules mandate the use of a 70 kg body
weight and an ingestion rate of 2 liters of water per day in the calculation of a systemic
threshold concentration. If the child body weight and ingestion rate were used to calculate the
IMAC, this would have to be changed to an adult body weight and ingestion rate when
calculating the 2L number.
4. Site -specific number: EPA specifically calculated their number for people who live in the
vicinity of the Washington Works facility, where the average concentration of PFOA in the
blood was measured at 298 to 369 ppb. According to the Washington, West Virginia facility
reports, the emissions in 1999 — 2000 timeframe were 31,000 lbs in air and 56,000 lbs in water
-- this WV facility has significantly reduced emissions in the last few years to 200 lbs in air
and 1500 lbs in the water(reported in 2004). To compare the basic exposure of NC citizens ,
"Biennial Report for APFO Manufacture" for Calendar Years of 2004 and 2005 reported to the
US EPA for the Dupont Fayetteville Works Site in Bladen County, North Carolina indicates
an air emission rate of 55.5 lbs in air and <1.6 lbs in water.
DEQ-CFW 00001985