Safe and effective disinfection of show cave infrastructure in a time of COVID-19

The COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, has been responsible for over 650,000 deaths worldwide. Transmission of SARS-CoV-2 occurs primarily through airborne transmission or direct human contact, demonstrating the importance of social distancing measures and the use of face masks to prevent infection. Nonetheless, the persistence of coronavirus on surfaces means that disinfection is important to limit the possibility of contact transmission. In this paper, the potential for various surfaces in show caves to serve as sources for SARS-CoV-2 infection is examined. Given the isoelectric potential (pI) of SARS and SARS-like coronaviruses, it is likely that they are adsorbed via electrochemical interactions to (limestone) rock surfaces, where the high humidity, pH and presence of biocarbonate ions will quickly lead to inactivation. Nonetheless, show caves contain infrastructure made of other non-porous surfaces that are more permissive for maintaining coronavirus viability. The 423 antiviral products approved by the US Environmental Protection Agency (EPA) were curated into 23 antiviral chemistries, which were further classified based on their potential to be hazardous, impact cave features or ecosystems, and those compounds likely to have the minimum impact on caves. The results suggest that alcohols (70% ethanol), organic acids (citric and lactic acid) and dilute hypochlorite represent the best disinfectants for in-cave use on non-porous surfaces. These disinfectants are able to inactivate coronaviruses inecosystems.