Why is there a handwritten “BRL” next to a detected chemical?
A handwritten BRL means that the reviewing chemist has determined that the chemical identified in the laboratory is a false positive. For every private well sample analyzed, there are also two other “test” samples analyzed. These “test” samples are called trip and method blanks. Both contain distilled water and are used to alert the chemist to chemical contamination that may have been introduced en route to the laboratory or during analysis. Any chemical detected in either the trip or the method blank and the private well sample is likely due to laboratory contamination (introduced after the sample was collected), and therefore a handwritten BRL qualifier is placed next to the number.
