Comparisons among lead paint field screening test methods

Abstract

Leaded paints are known to present a potential health risk if ingested. There are several field screening and laboratory methods to determine if walls are painted with lead-containing coatings. A common type of field screening method is a colorimetric chemical reaction with the painted surface which is intended to produce qualitative ‘yes/no’ results. This method results in some small damage to the coated surface. X-ray fluorescence is a nondestructive field screening device which can produce slightly more quantitative data although the results are often reported in reference to being above or below the HUD criteria. US Environmental Protection Agency (US EPA) laboratory methods to quantify lead in coated surfaces include atomic absorption (AA) and inductively coupled plasma (ICP). Three series of tests were conducted to determine the capability and characteristics of four field screening devices (three colorimetric, one X-ray fluorescence) to detect lead content on painted walls. Laboratory analysis was used to determine base lead levels in the test paints. The first test series evaluated the apparent detection threshold of three colorimetric field screening kits using the manufacturers' definition of a positive result. The second series of tests examined the effect of multiple layers of leaded and nonleaded paints on the colorimetric and X-ray fluorescence detection methods. The third series of tests examined the qualitative effect of such things as paint color, application method, and surface preparation on three colorimetric test kits.