Question

When determining risk, it is necessary to estimate all routes of exposure in order to determine a total dose (or CDI). Recognizing this, estimate the total chronic daily intake of toluene from exposure to a city water supply that contains toluene at a concentration equal to the drinking water standard of 1 mg/L over a period of 10 years. Assume the exposed individual is an adult female that is exposed to the chemical via drinking water and inhaling gaseous toluene released while she showers. Use the given parameters to calculate the CDI for water consumption. For inhalation, assume the woman takes a 15-minute shower every day. Assume the average air concentration of toluene during the shower is 1 μg/m3 and that she breathes at the adult rate of 20 m3/day.

Answer 1

Answer:

The following are the solution to this question:

Explanation:

The Formula for calculating CDI:

$\bold{CDI = \frac{C \times CR \times EF \times ED}{BW \times AT}}$

$_{where} \\ CDI = \text{Chronic daily Intake rate} (\frac{mg}{kg-day})} \\\\\text{C = concentration of Toluene}\\\\\text{CR = contact rate} \frac{L}{day}\\\\\text{EF = Exposure frequency} \frac{days}{year}\\\\\text{ED = Exposure duration (in years)} = 10 \ \ years\\\\\text{BW = Body weight (kg) = 70 kg for adult}\\\\ \text{AT = average period of exposure (days) }$

calculating the value of AT:

$= 365 \frac{days}{year} \times 70 \ year \\\\ = 25550 \ days$

 calculating the value of Intake based drinking:

$C = 1 \ \frac{mg}{L}$

$CR = 2 \frac{L}{day}$ Considering that adult females eat 2 L of water a day,

EF = 350 $\frac{days}{year}$ for drink

calculating the CDI value:

$\to CDI = \frac{(1 \times 2 \times 350 \times 10)}{(70 \times 25550)}$

             $= \frac{(2 \times 3500)}{(70 \times 25550)}\\\\ = \frac{(7000)}{(70 \times 25550)}\\\\ = \frac{(100)}{(25550)}\\\\=0.00391 \frac{mg}{ kg-day}$

Centered on inhalation, intake:

$C = \frac{1 \mu g} { m^3} \ \ \ or \ \ \ \ 0.001 \ \ \frac{mg}{m^3}\\\\CR = 20 \frac{m^3}{day}\\\\EF = 15 \frac{min}{day} \ \ or\ \ 5475 \frac{min}{yr} \ \ \ or \ \ 3.80 \frac{days}{year}$

calculating the value of CDI:

$\to CDI = \frac{(0.001 \times 20 \times 3.80 \times 10)}{(70 \times 25550)}$

             $= \frac{(0.76)}{(1788500)}\\\\= 4.24 \times 10^{-7} \ \ \frac{mg}{kg-day}$