Modeling infection from SARS-CoV-2 wastewater concentrations: promise, limitations, and future directions.

Estimating total infection levels, including unreported and asymptomatic infections, is important for understanding community disease transmission. Wastewater can provide a pooled community sample to estimate total infections that is independent of case reporting biases toward individuals with moderate to severe symptoms and by test-seeking behavior and access. We derive three mechanistic models for estimating community infection levels from wastewater measurements based on a description of the processes that generate SARS-CoV-2 RNA signals in wastewater and accounting for the fecal strength of wastewater through endogenous microbial markers, daily flow, and per-capita wastewater generation estimates.

Has Water Quality Improved or Been Maintained? A Quantitative Assessment Procedure.

Many policies require reporting on water quality trends. This is usually addressed by testing a hypothesis positing that there was zero slope in some parameter of the sampled population over a given period. Failure to achieve "statistical significance" is often falsely interpreted as evidence that there was no trend of concern-the -value of these tests can become ever smaller as the sample size increases and so also can the detectable trend.

Statistical Considerations in Environmental Microbial Forensics.

In environmental microbial forensics, as in other pursuits, statistical calculations are sometimes inappropriately applied, giving rise to the appearance of support for a particular conclusion or failing to support an innately obvious conclusion. This is a reflection of issues related to dealing with sample sizes, the methodologies involved, and the difficulty of communicating uncertainties. In this brief review, we attempt to illustrate ways to minimize such problems.

Assessing environmentally significant effects: a better strength-of-evidence than a single P value?

Interpreting a P value from a traditional nil hypothesis test as a strength-of-evidence for the existence of an environmentally important difference between two populations of continuous variables (e.g. a chemical concentration) has become commonplace.

Adenovirus-associated health risks for recreational activities in a multi-use coastal watershed based on site-specific quantitative microbial risk assessment.

We used site-specific quantitative microbial risk assessment (QMRA) to assess the probability of adenovirus illness for three groups of swimmers: adults with primary contact, children with primary contact, and secondary contact regardless of age. Human enteroviruses and adenoviruses were monitored by qPCR in a multi-use watershed and Adenovirus type 40/41 was detected in 11% of 73 samples, ranging from 147 to 4117 genomes per liter. Enterovirus was detected only once (32 genomes per liter).

Discharge-based QMRA for estimation of public health risks from exposure to stormwater-borne pathogens in recreational waters in the United States.

This study is the first to report a quantitative microbial risk assessment (QMRA) on pathogens detected in stormwater discharges-of-concern, rather than relying on pathogen measurements in receiving waters. The pathogen concentrations include seven "Reference Pathogens" identified by the U.S.

Modification, calibration and verification of the IWA River Water Quality Model to simulate a pilot-scale high rate algal pond.

We implemented the IWA River Water Quality Model No. 1 (Reichert et al., 2001.

Explaining differential sources of zoonotic pathogens in intensively-farmed catchments using kinematic waves.

Surveys in streams draining intensively farmed catchments can, during flood events, indicate differential time-concentration patterns between a bacterial health-risk indicator (E. coli) and a major zoonotic pathogen that it seeks to indicate-Campylobacter. The indicator's peak concentration at a monitoring station can arrive ahead of the flood peak (the pollutograph leads the hydrograph), whereas the peak pathogen concentration arrives with the flood peak (the pollutograph and hydrograph peaks coincide).

Large-scale freshwater microbiological study: rationale, results and risks.

A fifteen-month fortnightly survey of microbial health risk indicators and pathogens has been carried out at 25 freshwater recreational and water supply sites distributed throughout New Zealand, for: E. coli, Clostridium perfringens spores, F-RNA bacteriophage, somatic coliphage, human enteroviruses, human adenoviruses, Cryptosporidium oocysts, Giardia cysts, Salmonella and Campylobacter. Sites were selected to represent five geographical areas covering New Zealand and five categories of predominant environmental impact: birds, dairy farming, forestry/undeveloped, municipal, and sheep/pastoral farming.

Uncertainty in most probable number calculations for microbiological assays.

Microbiological assays commonly use incubations of multiple tubes in a dilution series, and microorganism concentration is read as a most probable number (MPN) in standard tables for the observed pattern of positive tubes. Published MPN tables differ, sometimes substantially, because of use of approximate MPN calculation procedures, different rounding conventions in the results, and different methods of calculating confidence or credible intervals. We conclude that the first 2 issues can now be resolved by using recently developed exact MPN calculation methods and by reporting rounding conventions in standard tables.

Confidence of compliance: parametric versus nonparametric approaches.

Previous classical and Bayesian formulations of compliance assessment rules based on a nonparametric approach are compared with formulations based on the assumption that compliance assessment data have been randomly drawn from a normal population with unknown mean and variance. Graphs of parametric (Bayesian) "Confidence of Compliance" curves are presented. With one exception it is concluded that compliance rules based on a nonparametric approach are the more robust, as their formulation does not depend on any assumption as to the nature of the parent distribution and because rules devised under either approach are generally similar.