Kicking the Bucket in Illinois

Jane Rothert
Quality Assurance Chemist
Central Analytical Laboratory

The NADP’s Central Analytical Laboratory (CAL) pulls six National Trends Network (NTN) and Atmospheric Integrated Research Monitoring Network (AIRMoN) buckets at random after cleaning each week to check for residual contamination. If these “clean” buckets are determined to still be dirty (i.e., have concentrations outside set control limits), they are rewashed and rechecked. However, a sample size of six buckets represents only two percent of the total buckets washed each week and distributed to NTN and AIRMoN sites.

The IL11 Bucket Study was designed to follow all buckets used at the IL11 site for both NTN and AIRMoN for an entire year. The study addressed these questions: Do some buckets need multiple cleanings to be certified clean? Does sample concentration influence bucket cleanliness after washing? Is there a limited life expectancy for the buckets after which they are difficult or impossible to clean effectively?

At the start of the study, new buckets were clean with all analyte-of-interest concentrations below detection limit. No bucket was sent back into the field unless all analytes were below detection limit. The number of times a bucket needed to be washed, the relationship between the bucket’s cleanliness and the concentrations of analytes in the samples, and the concentration of the analytes found in “cleaned” buckets is discussed.