The concentration of lead in a water sample is found to be 3 ppb. To which of the following is this equivalent?
A) 0.003 mg lead per 1 kg of water
B) 0.03 mg lead per 1 kg of water
C) 0.3 mg lead per 1 kg of water
D) 3.0 mg lead per 1 kg of water

Question

Quizplus · Accepted Answer

ppb stands for "parts per billion". This is a unit used to express very small concentrations of substances in water. 1 ppb is equivalent to 1 microgram per 1 liter of water.

To convert 3 ppb to milligrams per kilogram (mg/kg), we need to use conversion factors.

First, we need to convert micrograms to milligrams. There are 1,000 micrograms in 1 milligram.

Next, we need to convert liters to kilograms. 1 liter of water weighs 1 kilogram.

Putting it all together:

3 ppb = 3 micrograms per 1 liter of water
3 micrograms = 0.003 milligrams
1 liter of water = 1 kilogram
So, 3 ppb = 0.003 mg lead per 1 kg of water.

Therefore, the best choice is A.

The Concentration of Lead in a Water Sample Is Found