b)
A petroleum refinery site has 3 points
soil contaminated with
Benzene (a Carcinogen). Exposure
concentration in soil is 3.6 mg/Kg. A
worker weighing 74 Kg works for 6
days a week on the site. The worker
ingests soil at the rate of 142
mg/day which is 70% contaminated
with soil from the site for exposure
duration of 1 year. Calculate risk
for Benzene (Slope factor = 1.5 x 10
Kg.day/mg) for the worker
working at site. Average life
expectancy is 72 years.
2
5.756 x 10-8
8.635 x 10-10
0.596
5.756 x 10-6
Answers
Answer:
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Answer:
Explanation:
The calculation of the risk for the worker can be performed as follows:
Determining the daily dose of Benzene:
Since the worker ingests soil at a rate of 142 mg/day and the soil is 70% contaminated with Benzene, the daily dose of Benzene would be 100 mg * 0.7 = 70 mg/day.
Determining the lifetime dose of Benzene:
Since the worker works for 6 days a week and the exposure duration is 1 year, the total number of working days per year is 6 * 52 = 312 days.
The lifetime dose of Benzene for the worker would be 70 mg/day * 312 days/year * 1 year = 22,224 mg.
Calculating the lifetime risk:
The lifetime risk can be calculated using the formula: lifetime risk = lifetime dose * slope factor
where the slope factor for Benzene is 1.5 x 10^-3 (Kg.day/mg).
So, the lifetime risk would be 22,224 mg * 1.5 x 10^-3 (Kg.day/mg) = 0.0333 (Kg.day).
Expressing the risk as a probability:
To express the risk as a probability, we need to divide the lifetime risk by the average life expectancy (72 years) and convert the units to years.
So, the lifetime risk as a probability would be 0.0333 (Kg.day) / (74 Kg * 72 years) = 5.756 x 10^-8.
Therefore, the risk for Benzene for the worker working at the site is 5.756 x 10^-8.