The Risk Assessment Information System

RAGs A Format for Aroclor^® 1254 - CAS Number 11097691

Aroclor^® 1254 is a is a viscous, light yellow liquid polychlorinated biphenyl (PCB) mixture containing approximately 21% C₁₂H₆Cl₄, 48% C₁₂H₅Cl₅, 23% C₁₂H₄Cl₆, and 6% C₁₂H₃Cl₇ with an average chlorine content of54%. PCBs are inert, thermally and physically stable, and have dielectric properties. In the environment, the behavior of PCB mixtures is directly correlated to the degree of chlorination. They have been used in closed systems such as heat transfer liquids, hydraulic fluids and lubricants, and in open systems such as plasticizers, surface coatings, inks, adhesives, pesticide extenders, and for microencapsulation of dyes for carbonless duplicating papers. Aroclor^® is strongly sorbed to soil and remains immobile when leached with water; however, the mixture is highly mobile in the presence of organic solvents. PCBs are resistant to chemical degradation by oxidation or hydrolysis. PCBs have high bioconcentration factors and tend to accumulate in the fat of fish, birds, mammals, and humans.

PCBs are absorbed after oral, inhalation, or dermal exposure and are stored in adipose tissue. The major route of PCB excretion is in the urine and feces; however, more important is the elimination in human milk. Accidental human poisonings and data from occupational exposure to PCBs suggest initial dermal and mucosal disturbances followed by systemic effects that may manifest themselves several years post-exposure. Initial effects are enlargement and hypersecretion of the Meibomian gland of the eye, swelling of the eyelids, pigmentation of the fingernails and mucous membranes, fatigue, and nausea. These effects were followed by hyperkeratosis, darkening of the skin, acneform eruptions, edema of the arms and legs, neurological symptoms, such as headache and limb numbness, and liver disturbance.

Data are suggestive but not conclusive concerning the carcinogenicity of PCBs in humans. However, hepatocellular carcinomas in three strains of rats and two strains of mice have led the EPA to classify PCBs as group B2, probable human carcinogen.

The following is a presentation of the toxicity information associated with Aroclor-1254:

• The Oral Chronic Reference Dose is 2.00E-05 (mg/kg-day).
• The Oral Chronic Reference Dose has a modifying factor of 1.
• The Oral Chronic Reference Dose has an uncertainty factor of 300.
• The Oral Chronic Reference Dose is based on the Arnold study from 1994.
• The Oral Chronic Reference Dose study critical effects are ocular exudate, inflamed and prominent Meibomian glands.
• The overall confidence in the Oral Chronic Reference Dose is medium.

• The Dermal Chronic Reference Dose is 1.80E-05 (mg/kg-day).
• The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.9000.

• The Oral Slope Factor is for exposure to soil or food is 2.00E+00 (mg/kg-day)-1.
• The Oral Slope Factor is for exposure to water is 4.00E-01 (mg/kg-day)-1.

• The Inhalation Unit Risk for exposure to soil or food is 5.7E-01 (mg/m3)-1.
• The Inhalation Unit Risk for exposure to water is 1.0E-01 (mg/m3)-1.

• The Dermal Slope Factor for exposure to soil or food is 2.22E+00 (mg/kg-day)-1.
• The Dermal Slope Factor for exposure to water is 4.44E-01 (mg/kg-day)-1.
• The Dermal Slope Factors are based on a gastrointestinal absorption factor of 0.9000.