POLYCYCLIC AROMATIC HYDROCARBONS

Overview

Functional Class

Food Contaminant
CONTAMINANT

Evaluations

Evaluation year: 2006

Comments:

The Committee concluded that 13 PAH compounds were genotoxic and clearly carcinogenic in animals. Given the fact that humans are exposed to mixtures of PAHs in food, the Committee considered oral bioassays in mice conducted with coal tar mixtures to be the most relevant to the assessment of risk to humans from foodborne PAH-contamination. The Committee applied a surrogate approach to the evaluation, in which benzo[a]pyrene was used as a marker of exposure to, and effect of, the 13 carcinogenic PAHs. Based on data from oral bioassays conducted in mice with coal tar mixtures, the Committee calculated margin of exposure values of 25, 000 and 10,000 between the BMDL10 value of 100 µg of benzo[a]pyrene/kg bw/day and mean and 95th-percentile intake levels of 4 and 10 ng/kg bw/d, respectively. Based on the derived margins of exposure, the Committee concluded that the estimated intakes of PAHs were of low concern for human health. Measures to reduce intake of PAHs could include avoiding contact of foods with flames, and cooking with the heat source above rather than below the food. Efforts should be made to reduce contamination with PAHs during drying and smoking processes.

Intake:

Mean: 4 ng/kg bw per day; high: 10 ng/kg bw per day (estimates for benzo[a]pyrene as a marker for polycyclic aromatic hydrocarbons (PAHs)). Intake levels in children estimated to be 2-2.5-fold higher than adults on a bodyweight basis. Higher intake values could be expected for high consumers of foods cooked over open fires or foods grown in heavily-contaminated areas.

Tolerable Intake:

NONE ESTABLISHED

Meeting:

Report:

TRS 930-JECFA 64/61

Tox Monograph:

FAS 55-JECFA 64/563

Toxicological study

Pivotal Study:

Study of carcinogenicity in B6C3F1 mice treated orally with coal tar mixtures (Culp, 1998). Groups of female mice (n=48/group) were administered one of two coal tar mixtures in the diet for 2 years, resulting in the corresponding dietary intake levels of benzo(a)pyrene: --Mixture 1: 0, 0.03, 0.09, 0.32, 0.96, 1.92, or 3.2 mg B(a)P/kg bw/d --Mixture 2: 0, 0.16, 0.52, or 1.1 mg B(a)P/kg bw/d. Dose-related increased incidences of forestomach squamous cell papillomas and carcinomas & alveolar and bronchiolar adenomas and carcinomas were noted. Using B(a)P as a surrogate for the effects of mixtures of carcinogenic PAHs, BMDL10 values of 0.1-0.23 mg/kg bw/d were derived. The lower limit of the BMDL10 range of 0.1 mg/kg bw/d was chosen as the most conservative point of departure.

Animal Specie:

Female B6C3F1 mice

Effect:

Carcinogenicity

NOEL:

None can be established

PTWI:

None established, genotoxic carcinogen

Point of departure:

BMDL: 100 µg of benzo[a]pyrene/kg bw/day