Study Design Features of a Longitudinal Investigation of Acute Health Effects and Community-Level Class B Biosolids Exposure: Subject Recruitment and Exposure Assessment

Abstract

P-554 Abstract: There exists growing concern of the safety of current biosolids land application practices in the United States (US). The US Environmental Protection Agency requires that Class A biosolids be treated to eliminate indicator organisms and pathogens, while Class B biosolids contain detectable levels of indicator organisms, pathogens, and irritant chemicals. Most biosolids applied to land in the US are Class B. A recent National Academy of Sciences report underscored the inadequacy of current research into the safety of land application of biosolids in the US (NRC 2002). This paper will present strengths and weaknesses of two study design features of a proposed investigation of acute health effects and community-level exposure to treated sewage sludge (Class B biosolids) in North Carolina (NC) and Virginia (VA). We will present strengths and weaknesses related to: 1) Recruitment of study subjects and 2) Exposure assessment, for a proposed interdisciplinary community-based participatory (CBPR) research effort. Our presentation will discuss issues related to recruitment of a cohort of residents living near Class B biosolids application sites and recruitment of a separate control cohort of residents living in areas unaffected by biosolids exposure. Additionally, strengths and weaknesses of exposure assessments conducted previously by other investigators will be highlighted. Future plans for a collaborative CBPR effort to prospectively quantify frequency, duration, and intensity of off-site exposures through longitudinal repeated measures in target counties in NC and VA will be presented. Finally, we will report the results of a community workshop where residents in affected communities discussed the feasibility of conducting subject recruitment and an exposure assessment involving repeated environmental measures of certain microbial (fecal indicators, coliphages, antibiotic resistant E. coli, Salmonella, and Staphylococcus aureus) and chemical (PM10,, endotoxins, H2S, ammonia, and VOCs) contaminants in target communities.