CDPH Lead Inspector/Assessor California State Practice Exam

What unit of measurement is used for lead in water?

1. Parts per million (ppm)

2. Parts per billion (ppb)

3. Milligrams per liter (mg/L)

4. Micrograms per liter (μg/L)

The correct answer is: Parts per billion (ppb)

The correct unit of measurement for lead in water is parts per billion (ppb). This measurement is particularly important in the context of drinking water and environmental assessments because lead is a toxic substance that can have serious health effects, even at very low concentrations. Using parts per billion allows for the detection of trace amounts of lead, which is critical since its presence in water is often undesirable and regulated due to its potential health impacts. Since water can be consumed in relatively small volumes, measuring contaminants like lead in ppb helps ensure that even minute quantities are monitored effectively. While other units such as parts per million (ppm) and milligrams per liter (mg/L) are also relevant in various contexts of environmental health and safety, ppb is the preferred measurement when dealing with very low concentrations of contaminants like lead in water sources. This is due to the need for high sensitivity in water testing, reflecting the environmental standards and regulations designed to protect public health.