Question

Estimate the incremental cancer risk for a 60-kg worker exposed to a

particular carcinogen under the following circumstances. Exposure time is 5
days per week, 50 weeks per year, over a 25-year period of time. The worker is
assumed to breathe 20m3 of air per day. The carcinogen has a potency factor
of 0.02 (mg/kg-day)-1 and its average concentration is 0.05mg/m3. Average Life
is 70-year.
1year=365 day

Answer 1

Carcinogen conc. = 0.05 mg/m3

; Lung absorption factor =0.8; Breathing rate = 1m3

/hr

Carcinogen potency factor = 0.02 (mg/kg-day)

-1

Total exposure time = (2 hours/work day)×(5 days/week)×(50 weeks/year)×(20 years)

= 10000 hours

Exposed carcinogen concentration = (0.05 mg/m3

)×[ 1 m3

/h]× (10000 hours) = 500 mg

Absorbed carcinogens in lung = (0.8)×500 mg = 400 mg

Chronic daily intake of carcinogen through lung (CDI)

= (Exposed concentration)/(body weight× averaging time)

Here given body weight = 60 kg; Averaging time = 70 years

So, CDI= (400 mg)/(60 kg×70 years×365days/year) = 2.61 ×10-4 mg/(kg×day)

Lifetime incremental risk of cancer through inhalation of air = CDI×PF

=[2.61 ×10-4 mg/(kg×day)]×[ 0.02 (mg/kg-day)

-1

] =5.22×10-6 (> than the allowable lifetime

incremental risk of cancer, i.e., 10-6, and thus there is a concern.)

Step-by-step explanation: