Chapter 3 FE EXAM FORMATTED PROBLEMS
3-1.
A four year old child has been playing in soil contaminated with 500 mg/kg of
tetrachloroethylene. It is estimated that he ingested 5g/d of soil over a single 3 month
period. The exposure frequency was 7 days per week. What is the estimated chronic daily
intake of tetrachloroethylene for the child over the 3 month period?
From Eq. 3-14
(CS )( IR)(CF )( FI )( EF )( ED)
( BW )( AT )
From Table : BW  16 kg
CDI 
EF  (7day / week)(3months / year)(4weeks/ month)  84 days/ year
CDI 
3-2.
(500 mg / kg)(5 g / day)(1000 mg / g )(10 6 kg / mg )(1.0)(84 day / year)
 0.156 mg / kg  d
(16 kg)(84 days)
Characterize the risk of an oral chronic daily intake of 50 ppb of arsenic.
From Table 3 - 3 Arsenic  1.5 kg  d mg
Risk  0.050 mg kg  d 1.5 kg  d mg   0.075
Because  0.01 use Eq. 3 - 19
Risk  1  exp 0.075   1  0.928  0.072
3-3.
Characterize the hazard of an oral chronic daily intake of 0.005mg/L of cadmium.
Using Table 3 - 4 and Eq. 3 - 20
0.005 mg/L
HI 
 10
0.0005 mg / L
3-4.
Estimate the concentration of Heptachlor in fish if the concentration in water is 5 ppb.
The bioconcentration factor is 15,700.
1ppb  1g/L 5ppb  5g/L or 5  10 -3 mg/L
From Eq. 3 - 9


Concentration in fish  5  10 3 mg / L 15700 L / k g  78.5mg / k g