Practice-based evidence informs environmental health policy and regulation: A case study of residential lead‐soil contamination in Rhode Island

Abstract

Prior to 1978, the exteriors of Rhode Island's municipal water towers were painted with lead-containing paint. Over time, this lead-containing paint either flaked-off or was mechanically removed and deposited on adjacent residential properties. Residents challenged inconsistencies across state agencies and federal requirements for collecting and analyzing soil samples. The purpose of this case study was to evaluate the efficacy of Rhode Island Department of Health (RIDOH) soil sampling regulations in determining the extent of lead contamination on residential properties using real world data. Researchers interviewed key government personnel, reviewed written accounts of events and regulations, and extracted and compiled lead data from environmental soil sampling on 31 residential properties adjacent to six municipal water towers. Data were available for 498 core samples. Approximately 26% of the residential properties had lead soil concentrations >1,000 mg/kg. Overall, lead concentration was inversely related to distance from the water tower. Analysis indicated that surface samples alone were insufficient to classify a property as “lead safe”. Potential for misclassification using RIDOH regulations was 13%. For properties deemed initially “lead free”, the total number of samples was too few to analyze. Post-remediation lead-soil concentrations suggest the extent of lead contamination may have been deeper than initially determined. Additional data would improve the ability to draw more meaningful and generalized conclusions. Inconsistencies among regulatory agencies responsible for environmental health obfuscate transparency and erode the public's trust in the regulatory process. Recommendations for improvement include congruency across departmental regulations and specific modifications to soil sampling regulations reflective of lowered CDC reference blood lead value for children 1 to 5 years old (5μg/dL). While scientific research informed the initial development of these environmental health policies and regulations, practice-based evidence did not support their efficacy in context of real world practice.

Lead and other heavy metals in soils impacted by exterior legacy paint in residential areas of south west England

“…Results are exemplified in Figure 2 for soils collected at different distances from the telephone kiosk on Dartmoor, where all heavy metals were present in the paint at relatively high concentrations but additional anthropogenic sources are absent. Here, values of EF reveal an exponential reduction for all metals to a distance of 3 to 5 m, a distribution that is characteristic of a point-source of particulate metal, like paint, rather than a diffuse one (Clark and Knudsen, 2013;Thompson et al, 2014).…”

Urban Gardening: Managing the Risks of Contaminated Soil

“… 1 , 11 , 12 Contaminants tend to concentrate in low-income neighborhoods with large minority populations—although rural areas are not immune. 12 , 13 , 14 …”

“…Soil data from Rhode Island yards showed that lead-based paint spread more than 400 feet from nearby water towers, and often penetrated more than 12 inches below the soil surface. 14 “The heterogeneity of contaminant distribution is one of the biggest challenges,” says Hettiarachchi. “You cannot actually afford to run so many samples.”…”

Lead exposure in childhood and historical land use: a geostatistical analysis of soil lead concentrations in South Philadelphia parks

“…The urban environment consists of various outdoor areas where children can be exposed to elevated soil Pb concentrations including public parks (Han et al, 2017;Pavilonis et al, 2021), playgrounds (Takaoka et al, 2006), and residential soils (Bradham et al, 2017;Thompson et al, 2014). Inhalation and/or ingestion of Pb-contaminated soils has been shown to be one of the most important exposure pathways in childhood (Mielke et al, 2016;Mielke & Reagan, 1998).…”

“…Pb soil contamination can be considered a function of legacy sources of Pb (i.e., lead-based paint, leaded gasoline, industrial operations) and their accumulation in urban soils (Mielke & Reagan, 1998;Han et al, 2017;Pavilonis et al, 2021). Numerous studies have identified public parks and residential soils as primary urban sources and reservoirs for accumulated lead dust (Sun et al, 2021;Thompson et al, 2014;Pavilonis et al, 2021;Mielke & Reagan, 1998;Duzgoren-Aydin et al, 2006). According to data provided by the 2007-2010 US Geological Survey Background Soil Lead Survey, the 95th and 99th percentiles for background soil Pb concentrations in the state of Pennsylvania were identified as 153 ppm and 261 ppm respectively (USEPA, 2022).…”