Environmental Protection Agency (EPA) Lead Risk Assessor Practice Exam

How many dust wipe blanks are needed according to risk assessment guidelines?

1. 1 for each dwelling unit

2. 4 per composite sample

3. 2 for every 30 samples

4. 3 for every composite sample

The correct answer is: 4 per composite sample

In lead risk assessments, the use of dust wipe blanks is an essential part of ensuring the accuracy and reliability of sampling results. The inclusion of dust wipe blanks serves to assess the potential for contamination that may occur during the sampling process, thereby helping to produce valid and defensible data. The correct number of dust wipe blanks required, which is indicated by the guidelines, is based on the need to effectively monitor and maintain the integrity of the samples collected. When you take a composite sample from an area, having four dust wipe blanks helps to account for possible contamination or inconsistencies in how samples were collected, providing a better understanding of the overall lead levels present. This number strikes a balance, allowing for adequate representation of how sampling conditions can affect results without introducing excessive complexity into the assessment process. Ensuring that this number of blanks is utilized is key to obtaining meaningful data that accurately reflects lead exposure risks.