Question

A field worker is exposed to a xylene for a duration of 8 weeks at 40 hrs/wk. The concentration of xylene in the workplace is 40 μg/m3. The worker is inhaling air at a rate of 0.9 m3/hr. Assuming 70 kg body mass, the chronic daily intake (CDI) [mg/(kg-d)] during the period of exposure is most nearly.

Answer 1

Answer:

The chronic daily intake during the period of exposure is most nearly 0.012 mg/kg day.

Explanation:

Number of hours worker exposed to xylene = $40 hr/week\times 8 week = 320 hours$

The concentration of xylene in the workplace =$40 \mu g/m^3$

The worker is inhaling air at a rate of $0.9 m^3/hr$.

Amount xylene inhaled by worker in an hour :

= $40\mu g/m^3\times 0.9 m^3/hr=36 \mu g/hr$

Amount xylene inhaled by worker in 320 hours:

$36 \mu g/hr\times 320 hr=11,520 \mu g=11,520\times 0.001 mg=11.520 mg$

1 μg = 0.001 mg

Amount xylene inhaled by worker in 320 hours = 11.520 mg

1 day = 24 hours

Amount xylene inhaled by worker in 1 day:

$\frac{24}{320}\times 11.520 mg=0.864 mg$

Assuming 70 kg body mass, the chronic daily intake of xylene :

$\frac{0.864 mg/day}{70 kg}=0.01234 mg/ kg day\approx 0.012 mg/ kg day$

The chronic daily intake during the period of exposure is most nearly 0.012 mg/kg day.