CDPH Lead Inspector/Assessor California State Practice Exam

Where should composite wipe samples be composited, and how many samples per composite?

1. In the lab, 3

2. In the field, 2

3. In the field, 4

4. In the lab, 5

The correct answer is: In the field, 4

Composite wipe samples should be prepared in the field to ensure that the samples accurately reflect the conditions of the environment being tested. By collecting and compounding the samples on-site, you account for any potential variability that may exist due to environmental factors, such as humidity or surface conditions, which could alter the lead dust levels being measured. The standard practice for compositing wipe samples involves combining a certain number of samples to provide a representative average of a larger area. Compositing four samples in the field is typical, as it strikingly balances accuracy and practical logistics. This method helps in obtaining a more robust and reliable result that represents the lead contamination across a wider space, which can be critical for assessing risk and determining the next steps in lead hazard management. Collecting a different number of samples or compositing them in the lab would not align with the established guidelines. For instance, compositing more or fewer samples could hinder the representative nature of the result, while laboratory compositing may overlook important field-specific variables that could affect contamination levels.