Challenges in Using Handheld XRFs for In Situ Estimation of Lead Contamination in Buildings

Determination of dielectric properties of lead-contaminated soils: Potential application to soil remediation

This research investigated the effectiveness of radio frequency (RF) heating as a treatment for lead-contaminated soil, assessing its impact through dielectric constant measurements. Using water-soluble lead (II) acetate trihydrate, the study analyzed the impact of RF heating on soil dielectric properties under various soil moisture conditions (high, medium, and low) and electric field strengths (112.5, 150, 225, and 450 kV/m). The results indicated that soil temperature increased with lead concentration, highlighting significant changes in soil thermodynamics. Under high-humidity conditions, temperature increases were more pronounced, suggesting that higher lead concentrations elevate soil temperatures. Moreover, RF heating consistently reduced the dielectric constant as lead concentration increased, which was especially evident at higher electric field strengths. The study found that the soil resistivity approached that of uncontaminated soil, particularly at 450 kV/m electric field strength, with the highest removal rate of 46.154%. This investigation provides valuable insights into the application of RF heating for soil quality improvement in lead-contaminated environments, demonstrating how dielectric properties can reflect those of uncontaminated soil.

Lead in painted surfaces and dusts from rented urban properties (Plymouth, UK)

X-ray fluorescence (XRF) spectrometry has been used to measure lead (Pb) in painted surfaces and indoor dusts from 14 rented properties in the city of Plymouth, UK. Lead was detected in 78 out of 164 surfaces measured (and in 69 out of 150 interior surfaces) with an overall median concentration of 7100 mg kg^-1 (range from 157 to 139,000 mg kg^-1), and was detected in all but two properties that included one building constructed within the last 25 years. Selected measurements on an area basis (n = 48) returned Pb concentrations ranging from below 0.01 to 16.1 mg cm^-2 that were significantly correlated with concentrations on a mass basis but with scatter that was attributed to the degree to which leaded paint had been overpainted. As potential measures of Pb exposure, mean concentrations in samples of lint (n = 8) were <15 mg kg^-1 while mean concentrations in hoovered dusts (n = 14) were more variable; specifically, mean Pb dust concentrations ranged from ∼20 to 140 mg kg^-1 in 13 samples but was ∼4500 mg kg^-1 in a property that had recently undergone extensive renovation. Although mean concentrations of Pb in lint or dust were not related to median Pb concentrations in paint, a strong correlation between barium (Ba) and Pb in dusts suggests that paint is the main source of dust Pb. This study indicates that, in most cases, leaded paints historically applied to interior surfaces have been over-coated and pose little risk, provided that surface coatings are in good condition. However, inappropriate practices during renovation can result in significant contamination of dusts. Our findings are likely to be more broadly applicable to the urban rented sector in the UK and landlords and tenants should, therefore, be made aware of government guidance on the safe decoration or remodelling of older properties where leaded paint is pervasive.