Question

The suspended solid content of a 1-liter river water sample is 20 mg/liter. Assume this material is all organic carbon and the K_oc, the organic carbon-water partition coefficient for a chemical of interest, is approximately 4000 liter/kg. A laboratory filters the sample before analysis, analyzing the filtrate (water that does pass through the filter) and reporting the chemical concentration, C, of the filtrate. If the sample had not been filtered, how much of this chemical would have been measured? Express in terms of the measured concentration C (mg/liter) of the filtered sample.

Answer 1

The given concentration of river water sample = 20 mg/liter

Given that the organic carbon-water partition coefficient = 4000 liter/Kg

Now, if the sample had not been filtered, the concentration of this chemical that would have been measured can be calculated as follows.

20 mg .......... per 1 liter

x mg .......... per 4000 liter

i.e. x = (4000 liter/1 liter) * 20 mg

i.e. x = 80000 mg

i.e. x = 800*10² mg

i.e. x = 800 g