Abstract:
The motivation of our review article1 was to respond to emerging concerns, regarding the risk of SARS-CoV-2 in treated wastewater and natural water bodies. There had been a complete lack of quantitative risk assessment regarding presence of SARS-CoV-2 in wastewater. Since the available knowledge had been limited, the review article aimed to estimate the ceiling of possible risk based on the simplest assumptions, following the precautionary principle. The major question raised in the Matters Arising by Haas et al. is that the estimated risk in our review article is overestimated by lacking plausible assumptions in presence of infectious virus in water and inhalation dose in recreational water activities. For the purpose to estimate the ceiling of possible risk, the assumptions were basically made on the safety side (or the worst-case condition), which intentionally allowed potential overestimation. The important conclusion of this review is that, even with such worst-case assumptions, the risk of SARS-CoV-2 in water bodies receiving treated wastewater is probably not a matter of serious concern unless the SARS-CoV-2 RNA in wastewater exceeds the previously detected range. Here, we explain our standpoints to the questions raised in the Matters Arising.