SARS-CoV-2 and other viruses in soil: An environmental outlook

Abstract

In the present review, the authors shed light on the SARS-CoV-2 impact, persistence, and monitoring in the soil environment. With this purpose, several aspects have been deepened: i) viruses in soil ecosystems; ii) direct and indirect impact on the soil before and after the pandemic, and iii) methods for quantification of viruses and SARS-CoV-2 monitoring in soil. Viruses are present in soil (i.e. up to 417 × 10⁷ viruses per g TS^-1 in wetlands) and can affect the behavior and ecology of other life forms (e.g. bacteria), which are remarkably important for maintaining environmental equilibrium. Also, SARS-CoV-2 can be found in soil (i.e. up to 550 copies·g^-1). Considering that the SARS-CoV-2 is very recent, poor knowledge is available in the literature on persistence in the soil and reference has been made to coronaviruses and other families of viruses. For instance, the survival of enveloped viruses (e.g. SARS-CoV) can reach 90 days in soils with 10% of moisture content at ambient. In such a context, the possible spread of the SARS-CoV-2 in the soil was evaluated by analyzing the possible contamination routes.

Keywords: COVID-19; Coronavirus; Human viruses; Soil environment; Viral abundance; Virus monitoring.

Graphical abstract

Fig. 1

Viral (viruses·g TS⁻¹) and bacterial (cells·mL⁻¹) abundance in various soil types (i.e. cold and hot deserts, wetlands and agricultural soils). The values are the means and standard deviations of the reported data for each soil. The virus to bacteria ratio (VBR) was calculated assuming a conversion factor of 1 g mL⁻¹ for bacterial abundance (Srinivasiah et al., 2008). Data were taken from Williamson et al. (2017, , .

Fig. 2

Possible scenarios regarding the fate of SARS-CoV-2 in soil. SARS-CoV-2 can arrive in soil due to the discharge of infected effluent and digestate after an improper wastewater treatment. Afterwards, the virus can be taken by plants requiring the phosphorus, adsorbed onto clay minerals and organic substances due to electrostatic and hydrophobic interactions, respectively. Otherwise, SARS-CoV-2 can migrate from soil to other environmental compartments due to the reduction of ionic strength during rains. The virus survival can be limited by sunlight radiation, high temperature, acidic pH and the presence of pollutants.

Fig. 3

A sequence of operations for SARS-CoV-2 detection and quantification in soil.