CDPH Lead Inspector/Assessor California State Practice Exam

What unit of measurement is used for lead in XRF readings?

1. Micrograms per square centimeter (μg/cm2)

2. Micrograms per gram (μg/g)

3. Milligrams per square centimeter (mg/cm2)

4. Ppm (parts per million)

The correct answer is: Milligrams per square centimeter (mg/cm2)

The correct unit of measurement for lead in XRF (X-ray fluorescence) readings is expressed as milligrams per square centimeter (mg/cm²). This measurement indicates the concentration of lead on the surface of a material, typically used in environmental assessments, including paint and dust samples. XRF technology provides a surface analysis that quantifies the amount of lead present, and the miligrams per square centimeter measurement reflects the weight of lead per unit area, which is ideal for assessing lead contamination in various surfaces. This unit is particularly relevant in scenarios where surface lead levels are critical for safety assessments and regulatory compliance. The other units listed serve different purposes or contexts. For instance, micrograms per square centimeter (μg/cm²) is often used in laboratory settings for detecting lower levels of contaminants but does not align with the standard reporting format for XRF data in practical applications. Micrograms per gram (μg/g) would be applicable for bulk materials rather than surface measurements, and ppm (parts per million) is generally used for expressing concentrations in liquids or air, rather than specific surface measurements.