Environmental Protection Agency (EPA) Model Lead Based Paint Risk Assessor Practice Test

Convert 5,000 µg/g into which of the following units?

1. 5,000 ppm

2. 5,000 mg/kg

3. Both A and B

4. None of the above

The correct answer is: Both A and B

To understand why the correct answer is that 5,000 µg/g is equivalent to both 5,000 ppm and 5,000 mg/kg, it helps to clarify the relationships between these units of measurement. Micrograms per gram (µg/g) is a measure of concentration that indicates how many micrograms of a substance are present in one gram of material. When converting to parts per million (ppm), it is important to know that 1 ppm is equivalent to 1 µg/g, since 1 million grams is equal to 1,000 kilograms. Therefore, 5,000 µg/g directly translates to 5,000 ppm. On the other hand, when converting to milligrams per kilogram (mg/kg), it’s essential to recognize that 1 µg is equal to 0.001 mg. Since 1 gram (g) is equal to 1,000 milligrams (mg), this means that 5,000 µg/g is also equivalent to 5,000 mg/kg. Thus, the value remains the same whether expressed as µg/g, ppm, or mg/kg, emphasizing the direct equivalence of these measurements in the context of concentration. In summary, the conversion confirms that