Rapid new methods for paint collection and lead extraction

Abstract

Chronic exposure of children to lead can result in permanent physiological impairment. In adults, it can cause irritability, poor muscle coordination, and nerve damage to the sense organs and nerves controlling the body. Surfaces coated with lead-containing paints are potential sources of exposure to lead. In April 2008, the U.S. Environmental Protection Agency (EPA) finalized new requirements that would reduce exposure to lead hazards created by renovation, repair, and painting activities, which disturb lead-based paint. On-site, inexpensive identification of lead-based paint is required. Two steps have been taken to meet this challenge. First, this paper presents a new, highly efficient method for paint collection that is based on the use of a modified wood drill bit. Second, this paper presents a novel, one-step approach for quantitatively grinding and extracting lead from paint samples for subsequent lead determination. This latter method is based on the use of a high-revolutions per minute rotor with stator to break up the paint into approximately 50 micron-size particles. Nitric acid (25%, v/v) is used to extract the lead in <3 minutes. Recoveries are consistently >95% for real-world paints, National Institute of Standards and Technology's standard reference materials, and audit samples from the American Industrial Hygiene Association's Environmental Lead Proficiency Analytical Testing Program. This quantitative extraction procedure, when paired with quantitative paint sample collection and lead determination, may enable the development of a lead paint test kit that will meet the specifications of the final EPA rule.

Development and preparation of lead-containing paint films and diagnostic test materials

“…These aliquots were prepared for ICP-OES analysis by a variety of methods, including (1) grinding in a mortar and pestle and extracting by ultrasonic/nitric acid digestion; 29 grinding in a test tube and microwave-aqua regia acid extraction; 30 and the rotor/ stator-nitric acid extraction method. 25,26 The results for these analyses showed great variability between methods and for each method. The lead results varied by 5 to 50%.…”

“…The paint was brittle and easily broken after about 60 h at 150 C. This temperature and amount of time proved successful for subsequent work. Six baked paint film squares were ground up and extracted using the rotor/stator/nitric acid procedure 25,26 and analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). 27,28 The result was a mean value of 4.7 AE 0.7 (14.9%) mg lead/cm 2 .…”

“…The modified drill bit method was used to collect the paint samples from the wood and plaster substrate diagnostic test materials, while the chisel method was used to collect the samples from the metal and masonry substrate diagnostic test materials. 25 The results of analysis of these samples are presented in Table 10. Only three types, O, Z, and AE, did not meet the quality objective of the RSD for the areal concentration (mg lead/cm 2 ) because they were greater than 10%.…”

“…The diagnostic materials described in this paper were tested using this new method. The paint samples were collected using a drill or chisel, the lead was extracted from the paint using a rotor/stator procedure, 25,26 and the lead was quantified by the new turbidimetric method. The weights of the paint diagnostic material samples collected for the rotor-stator/turbidity method varied from 0.04 to 0.30 g, which reflects the variation in the complexity of the diagnostic materials (number of paint films, overlayers of paint, etc.)…”

Field turbidity method for the determination of lead in acid extracts of dried paint

“…Two methods available for directly measuring lead in paint in situ are field-portable X-ray fluorescence (FPXRF) and portable laser-induced breakdown spectroscopy (LIBS), both of which require extensive training and are relatively expensive. 4 The measurement requirements are more likely to be met using a quantitative, portable chemical test kit. This quantification will most likely be based on a quantitative reaction with solubilized lead using, for example, electrochemistry, complexation (colorimetry), or precipitation (gravimetry or turbidimetry).…”