CDPH Lead Inspector/Assessor California State Practice Exam

How deep must mulch or bark be applied to bare soil for lead hazard control?

1. 2-4 inches deep

2. 3-5 inches deep

3. 4-6 inches deep

4. 5-7 inches deep

The correct answer is: 4-6 inches deep

Applying mulch or bark to a depth of 4-6 inches is recognized as an effective measure for lead hazard control. This depth serves several purposes in minimizing lead exposure. First, it helps to cover bare soil, which is essential since bare soil can easily become a source of lead dust and contaminated soil particles that children or pets might disturb. By using 4-6 inches of mulch, you create a sufficient barrier that reduces the chances of direct contact with the contaminated soil, significantly lowering risks of ingestion or inhalation of lead particulates. This thickness is also effective in preventing the growth of weeds that might otherwise disturb the layer and contribute to potential exposure paths. In terms of effectiveness in lead hazard control, this range strikes a balance that ensures sufficient coverage while still allowing for maintenance and the health of the mulch material in terms of decomposition and moisture retention. Therefore, the recommended depth of 4-6 inches is aligned with guidelines for ensuring safe outdoor environments, particularly in areas where lead contamination is a known concern.