Answer: a) 0.0015 mg/L < 0.003 mg/L; so, no, it's not up to the EPA limit.
b) An average person takes in 0.003 mg atrazine per day
c) Concentration of atrazine in μmol/L = 0.00695 μmol/L
Explanation:
a) ppb = μg/L
1000 μg/L = 1 mg/L
1.5 ppb = 1.5 μg/L = (1.5/1000) mg/L = 0.0015 mg/L
0.0015 mg/L < 0.003 mg/L
The measured concentration isn't up to EPA regulated limit.
b) An average person takes in 2L of water daily,
2L of water contains (2 × 0.0015) mg of atrazine = 0.003mg.
An average person takes in 0.003 mg atrazine per day.
c) Chemical formula for atrazine is C8H14ClN5, molecular weight = 215.68 g/mol
Concentration in μmol/L = (concentration in μg/L)/(Molecular Weight)
concentration in μg/L = 1.5 μg/L
Molecular weight = 215.68 g/mol
Concentration in μmol/L = 1.5/215.68 = 0.00695 μmol/L
QED!