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

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 >1000 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 lead-soil sampling regulations reflective of lowered CDC reference blood lead value for children 1 to 5 years old (5 μg/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.