Effect of organic carbon on sorption of human adenovirus to soil particles and laboratory containers

A key factor controlling the relationship between virus release and human exposure is how virus particles interact with soils, sediments and other solid particles in the environment and in engineered treatment systems. Finding no previous investigations of human adenovirus (HAdV) sorption, we performed a series of experiments to evaluate the role of soil organic carbon (SOC) and solution-phase dissolved organic carbon (DOC) on sorption capacity and reversibility. In preliminary methodological studies, we found that as much as 99% of HAdV was lost from inorganic buffer suspensions in polypropylene (PP) laboratory containers, but little loss occurred when using suspensions with substantial amounts of DOC or with glass containers from either type of suspension. It was confirmed that this loss was due to sorption rather than inactivation by using lysis-based recovery techniques and qPCR measurements that do not depend on virus viability. In isotherm experiments, soils with 2% OC had ≈ four-fold greater sorption capacity for HAdV than 8% OC soils; moreover, the sorption capacity of 2% OC soils was reduced ≈ seven-fold with an aqueous solution containing 150 mg/L of humic acid. After sequential extractions, higher fractions of sorbed HAdV were released from 8% OC soils. The amounts of HAdV and OC released remained relatively constant throughout each extraction step, indicating that desorbed HAdV could be caused primarily by the detachment of SOC from soils. Overall, results from this study suggest that OC plays a critical role in the sorption and desorption of HAdV, and as a result, on its environmental fate and transport.