Unit cancer risk

Enviromnental tobacco smoke [unit cancer risk 2.80 x 10 (pg/mV ]... 

Multiply unit cancer risk by EDI to obtain worst case... 

Unit cancer risk (UCR) is defined as the sum of the slopes of lines drawn from the lowest apparent effective dose of the chemical throngh zero for each tnmor site... 

First, the highest appropriate unit cancer risk (UCR) is determined from the tumor data from the most sensitive species, strain, sex, and study (FDA, 2002). Tumor incidences not considered treatment related are omitted from analysis statistical significance is an important tool in evaluating the relationship of treatment to tumor induction. If only one dose was tested and only one type of tumor was induced, then the UCR is defined as the slope of the straight line of tumor incidence versus dose. 

The odor perception threshold for benzene in water is 2 ing/L. The benzene drinking water unit risk is 8.3 x lO L/pg. Calculate the potential benzene intake rate (mg benzene/kg-d) and the cumulative cancer risk from drinking water with benzene concentrations at half of its odor threshold for a 30 year exposure duration. 

The cancer risk from this ingestion at half of the odor threshold of 1 mg/L is calculated based on the benzene unit risk of 8.3 x lO L/pg or ... 

Cancer risk of pollutant = (Annual Average Concentration)(Unit Risk)... 

Qi — The upper-bound estimate of the low-dose slope of the dose-response curve as determined by the multistage procedure. The q, can be used to calculate an estimate of carcinogenic potency, the incremental excess cancer risk per unit of exposure (usually pg/L for water, mg/kg/day for food, and pg/m for air). 

Dorgan, J.F. et al.. Relationships of serum carotenoids, retinol, alpha-tocopherol, and selenium with breast cancer risk results from a prospective study in Columbia, Missouri (United States), Cancer Causes Control, 9, 89, 1998. 

Breast cancer is the most common cancer in women in the United States. Observational data indicated an association between HRT and breast cancer risk. The WHI was the first RCT to demonstrate an increased risk of invasive breast cancer among women taking HRT. In fact, the trial was stopped early owing to an increased incidence of breast cancer in women taking HRT (0.38%) compared with placebo (0.3%) (HR 1.26, 95% Cl 1-1.59). This translates into an NNTH of 1250 and 8 more cases of invasive breast cancer for every... 

The EPA classifies all radionuclides, including americium, as Group A (known human) carcinogens (EPA 1997b). Lifetime excess total cancer risk per unit intake or exposure for ingestion, inhalation, and external exposure to 241 Am and 243Am are included in Table 8-1. The EPA has not derived reference concentrations (RfCs) or reference doses (RfDs) for americium (IRIS 2001). 

Haemisegger E, Jones A, Steigerwald B, et al. 1985. The air toxics problem in the United States An analysis of cancer risks for selected pollutants. Washington, DC U.S. Environmental Protection Agency, Office of Air and Radiation (ANR-443). EPA-450/1-85-001. NTIS No. PB85-225175. 

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