Oxidative decomposition of soil organic matter determines the proportion of carbon that is either stored or emitted to the atmosphere as CO2. Full conversion of organic matter to CO2 requires oxidative mechanisms that depolymerize complex molecules into smaller, soluble monomers that can be respired by microbes. Current models attribute oxidative depolymerization largely to the activity of extracellular enzymes. Here we show that reactive manganese (Mn) and iron (Fe) intermediates, rather than other measured soil characteristics, best predict oxidative activity in temperate forest soils. Combining bioassays, spectroscopy, and wet-chemical analysis, we found that oxidative activity in surface litters was most significantly correlated to the abundance of reactive Mn­(III) species. In contrast, oxidative activity in underlying mineral soils was most significantly correlated to the abundance of reactive Fe­(II/III) species. Positive controls showed that both Mn­(III) and Fe­(II/III) species are equally potent in generating oxidative activity, but imply conventional bioassays have a systematic bias toward Fe. Combined, our results highlight the coupled biotic-abiotic nature of oxidative mechanisms, with Mn-mediated oxidation dominating within Mn-rich organic soils and Fe-mediated oxidation dominating Fe-rich mineral soils. These findings suggest microbes rely on different oxidative strategies depending on the relative availability of Fe and Mn in a given soil environment.

The majority of sewer systems in the United States and other countries are operated by public utilities. In the absence of any regulation, the public perception of wastewater monitoring for population health biomarkers is an important consideration for a public utility commission when allocating resources for this purpose. We conducted a survey in August 2021 as part of an ongoing COVID-19 community prevalence study in Louisville/Jefferson County, KY, US. The survey comprised seven questions about wastewater awareness and privacy concerns and was sent to approximately 35 000 households randomly distributed within the county. A total of 1220 adults were involved in the probability sample, and data from 981 respondents were used in the analysis. A total of 2444 adults additionally responded to the convenience sample, and data from 1751 respondents were used in the analysis. The samples were weighted to obtain estimates representative of all adults in the county. Public awareness of tracking the virus that causes COVID-19 in sewers was low. Opinions strongly support the public disclosure of monitoring results. Responses showed that people more strongly supported measurements in the largest areas (>50 000 households), typically representing population levels found in a large community wastewater treatment plant. Those with a history of COVID-19 infection were more likely to support highly localized monitoring. Understanding wastewater surveillance strategies and privacy concern thresholds requires an in-depth and comprehensive analysis of public opinion for continued success and effective public health monitoring.

The majority of sewer systems in the United States and other countries, are operated by public utilities. In the absence of any regulation, public perception of monitoring wastewater for population health biomarkers is an important consideration for a public utility commission when allocating resources for this purpose. In August 2021, we conducted a survey as part of an ongoing COVID-19 community prevalence study in Louisville/Jefferson County, KY. The survey comprised of seven questions about awareness of and privacy concerns and was sent to 32,000 households randomly distributed within the county. A total of 1,220 sampled adults participated in the probability sample, and 981 were used in analysis. A total of 2,444 adults additionally responded in the convenience sample, and 1,751 were used in analysis. The samples were weighted to produce estimates representative of all adults in the county. Public awareness of tracking COVID-19 virus in the sewers was low. Opinions about how data from this activity are shared strongly supported public disclosure of monitoring results. Responses showed more support for measuring the largest areas (>30,000 to 50,000 households) typically representing population levels found in a community or regional wastewater treatment plant. Those who had a history of COVID-19 infection were more likely to support highly localized monitoring. Understanding wastewater surveillance strategies and thresholds of privacy concerns requires in-depth, comprehensive analysis of public opinion for continued success and efficacy of public health monitoring.Graphic for Table of Contents (TOC)/Abstract Art