CDPH Lead Inspector/Assessor California State Practice Exam

How many wipe sample blanks should be included in testing?

1. One blank wipe for each dwelling unit sampled

2. One blank wipe for every 100 samples collected

3. Two blank wipes for every 50 field samples

4. Only one blank wipe is necessary regardless of number of samples

The correct answer is: One blank wipe for each dwelling unit sampled

Including one blank wipe for each dwelling unit sampled is essential to ensure the accuracy and reliability of the testing results for lead contamination. The primary purpose of a blank wipe is to account for any potential contamination that might occur during the sampling process. By having a blank wipe for each sampled unit, any lead detected can be accurately attributed to that specific dwelling rather than being a result of contamination during collection or handling. This approach allows for a more precise understanding of the lead levels present in each specific environment being tested, helping to differentiate between background contamination and actual lead hazards. It enhances the validity of the study by ensuring that the data obtained is as reflective of the actual conditions in each dwelling unit being assessed.