Campus node-based wastewater surveillance enables COVID-19 case localization and confirms lower SARS-CoV-2 burden relative to the surrounding community.

Wastewater-based surveillance (WBS) has been established as a powerful tool that can guide health policy at multiple levels of government. However, this approach has not been well assessed at more granular scales, including large work sites such as University campuses. Between August 2021 and April 2022, we explored the occurrence of SARS-CoV-2 RNA in wastewater using qPCR assays from multiple complimentary sewer catchments and residential buildings spanning the University of Calgary's campus and how this compared to levels from the municipal wastewater treatment plant servicing the campus. Real-time contact tracing data was used to evaluate an association between wastewater SARS-CoV-2 burden and clinically confirmed cases and to assess the potential of WBS as a tool for disease monitoring across worksites. Concentrations of wastewater SARS-CoV-2 N1 and N2 RNA varied significantly across six sampling sites - regardless of several normalization strategies - with certain catchments consistently demonstrating values 1-2 orders higher than the others. Relative to clinical cases identified in specific sewersheds, WBS provided one-week leading indicator. Additionally, our comprehensive monitoring strategy enabled an estimation of the total burden of SARS-CoV-2 for the campus per capita, which was significantly lower than the surrounding community (p≤0.001). Allele-specific qPCR assays confirmed that variants across campus were representative of the community at large, and at no time did emerging variants first debut on campus. This study demonstrates how WBS can be efficiently applied to locate hotspots of disease activity at a very granular scale, and predict disease burden across large, complex worksites.

Wastewater-based surveillance can be used to model COVID-19-associated workforce absenteeism.

Wastewater-based surveillance (WBS) of infectious diseases is a powerful tool for understanding community COVID-19 disease burden and informing public health policy. The potential of WBS for understanding COVID-19's impact in non-healthcare settings has not been explored to the same degree. Here we examined how SARS-CoV-2 measured from municipal wastewater treatment plants (WWTPs) correlates with workforce absenteeism. SARS-CoV-2 RNA N1 and N2 were quantified three times per week by RT-qPCR in samples collected at three WWTPs servicing Calgary and surrounding areas, Canada (1.4 million residents) between June 2020 and March 2022. Wastewater trends were compared to workforce absenteeism using data from the largest employer in the city (>15,000 staff). Absences were classified as being COVID-19-related, COVID-19-confirmed, and unrelated to COVID-19. Poisson regression was performed to generate a prediction model for COVID-19 absenteeism based on wastewater data. SARS-CoV-2 RNA was detected in 95.5 % (85/89) of weeks assessed. During this period 6592 COVID-19-related absences (1896 confirmed) and 4524 unrelated absences COVID-19 cases were recorded. A generalized linear regression using a Poisson distribution was performed to predict COVID-19-confirmed absences out of the total number of absent employees using wastewater data as a leading indicator (P < 0.0001). The Poisson regression with wastewater as a one-week leading signal has an Akaike information criterion (AIC) of 858, compared to a null model (excluding wastewater predictor) with an AIC of 1895. The likelihood-ratio test comparing the model with wastewater signal with the null model shows statistical significance (P < 0.0001). We also assessed the variation of predictions when the regression model was applied to new data, with the predicted values and corresponding confidence intervals closely tracking actual absenteeism data. Wastewater-based surveillance has the potential to be used by employers to anticipate workforce requirements and optimize human resource allocation in response to trackable respiratory illnesses like COVID-19.

Surveillance for SARS-CoV-2 and its variants in wastewater of tertiary care hospitals correlates with increasing case burden and outbreaks.

Wastewater-based SARS-CoV-2 surveillance enables unbiased and comprehensive monitoring of defined sewersheds. We performed real-time monitoring of hospital wastewater that differentiated Delta and Omicron variants within total SARS-CoV-2-RNA, enabling correlation to COVID-19 cases from three tertiary-care facilities with >2100 inpatient beds in Calgary, Canada. RNA was extracted from hospital wastewater between August/2021 and January/2022, and SARS-CoV-2 quantified using RT-qPCR. Assays targeting R203M and R203K/G204R established the proportional abundance of Delta and Omicron, respectively. Total and variant-specific SARS-CoV-2 in wastewater was compared to data for variant specific COVID-19 hospitalizations, hospital-acquired infections, and outbreaks. Ninety-six percent (188/196) of wastewater samples were SARS-CoV-2 positive. Total SARS-CoV-2 RNA levels in wastewater increased in tandem with total prevalent cases (Delta plus Omicron). Variant-specific assessments showed this increase to be mainly driven by Omicron. Hospital-acquired cases of COVID-19 were associated with large spikes in wastewater SARS-CoV-2 and levels were significantly increased during outbreaks relative to nonoutbreak periods for total SARS-CoV2, Delta and Omicron. SARS-CoV-2 in hospital wastewater was significantly higher during the Omicron-wave irrespective of outbreaks. Wastewater-based monitoring of SARS-CoV-2 and its variants represents a novel tool for passive COVID-19 infection surveillance, case identification, containment, and potentially to mitigate viral spread in hospitals.

Passive sampling and in vitro assays to monitor antiandrogens in a river affected by wastewater discharge.

Pharmaceuticals and personal care products, antibiotics, estrogens, and antiandrogens are found widely in aquatic environments. Monitoring studies by sampling surface water and effluents of wastewater treatment plants (WWTPs) have been conducted recently to monitor antiandrogens, which, along with estrogens, cause endocrine disruption. However, few studies have investigated antiandrogenic activity (AA) combined with a chemical analyses of emerging antiandrogens. Therefore, we analyzed the presence and persistence of 12 types of antiandrogens, atrazine, and carbamazepine using grab sampling and polar organic chemical integrative sampler (POCIS) along a river affected by WWTP discharges. Water and sediment samples were collected from the WWTP effluent (WW), as well as upstream (US) and downstream (DS) of the WWTP. We detected only tebuconazole, triclosan, propiconazole, and fluconazole during the two sampling campaigns in 2016 and 2017. Grab sampling of the site WW detected tebuconazole (7-77 ng/L), propiconazole (5-47 ng/L), and fluconazole (6-45 ng/L). However, the concentrations in the river water were below the detection limits. Nevertheless, fluconazole and triclosan were detected by POCIS in the site WW (45.7 and 26.8 ng/L, respectively) and all river samples ranges of 0.3-9.3 and 2.4-3.7, respectively. This detection was attributed to the limit of quantification of POCIS being lower than that of grab sampling. Nilutamide and triclosan were detected in the river sediment, suggesting that their concentrations in the water column were at least partly attenuated through sediment sorption. We also observed AA by analyzing POCIS extracts with the yeast androgen screen assay. The highest AA was found in the site WW and it was still observable several kilometers downstream of the point of discharge despite decreasing. Therefore, the WWTP effluent was most likely contributor to the persistent AA in the river.

Maximum-likelihood parameter estimation in terahertz time-domain spectroscopy.

We present a maximum-likelihood method for parameter estimation in terahertz time-domain spectroscopy. We derive the likelihood function for a parameterized frequency response function, given a pair of time-domain waveforms with known time-dependent noise amplitudes. The method provides parameter estimates that are superior to other commonly used methods and provides a reliable measure of the goodness of fit. We also develop a simple noise model that is parameterized by three dominant sources and derive the likelihood function for their amplitudes in terms of a set of repeated waveform measurements. We demonstrate the method with applications to material characterization.

Investigating the androgenic activity of ozonation transformation products of testosterone and androstenedione.

This study investigates the impact of ozonation on the concentration of two androgen steroid hormones, testosterone and androstenedione, and on androgenic activity as measured using the YAS assay. While these compounds are remarkably similar in chemical structure and showed comparable removal profiles in the presence and absence of a hydroxyl scavenger (isopropanol), large differences between percent removal of target compounds using chemical analysis and percent removal of bioactivity was observed when small ozone doses were applied. The dynamic change and initial increase in bioactivity during ozonation can be attributed to transformation products. These results demonstrate the importance of combining chemical analysis and bioanalytical techniques not only to perform a comprehensive assessment of environmental risks but also as a tool to optimize treatment technologies proposed as a mean to mitigate the impact of contaminants of emerging concern.

Endocrine Activities of Pesticides During Ozonation of Waters.

Two yeast-based bioassays were used to assess the endocrine activity potential of transformation products formed during the ozonation of water containing a variety of pesticides (propiconazole, atrazine, 2,4-dichlorophenoxyacetic acid [2,4-D], tebuconazole, climbazole, myclobutanil, irgarol, terbutryn, dicamba, mecoprop and diuron). Ozone experiments were conducted first in reverse osmosis water to isolate the effects of the pesticides and then in synthetic wastewater and wastewater effluent to investigate whether the results translated to more complex matrices. The findings demonstrate the recalcitrant nature of most pesticides during ozonation, with removals below 50%, except for irgarol, terbutryn and climbazole with removals up to 70%. This study is the first one to investigate the removal of the fungicides myclobutanil and tebuconazole by ozonation and is one of the first studies to investigate the androgenic activity of ozonation transformation products of contaminants of emerging concern. These findings also demonstrated that during ozonation the initial anti-androgenic activity was removed while the estrogenic activity remained undetected and the androgenic activity increased to levels up to 60% of the anti-androgenic activity of the DHT control. These results indicate that bioactivity should be considered in the evaluation of treatment performance and risks assessment associated to wastewater discharges.

Investigation of Acute and Chronic Toxicity Trends of Pesticides Using High-Throughput Bioluminescence Assay Based on the Test Organism Vibrio fischeri.

High-throughput acute and chronic toxicity tests using Vibrio fischeri were used to assess the toxicity of a variety of fungicides, herbicides, and neonicotinoids. The use of time points beyond the traditional 30 min of an acute test highlighted the sensitivity and applicability of the chronic toxicity test and indicated that for some compounds toxicity is underestimated using only the acute test. The comparison of EC50 values obtained from acute and chronic tests provided insight regarding the toxicity mode of action, either being direct or indirect. Using a structure-activity relationship approach similar to the one used in hazard assessments, the relationship between toxicity and key physicochemical properties of pesticides was investigated and trends were identified. This study not only provides new information regarding acute toxicity of some pesticides but also is one of the first studies to investigate the chronic toxicity of pesticides using the test organism V. fischeri. The findings demonstrated that the initial bioluminescence has a large effect on the calculated effective concentrations for target compounds in both acute and chronic tests, providing a way to improve and standardize the test protocol. In addition, the findings emphasize the need for additional investigation regarding the relationship between a toxicant's physicochemical properties and mode of action in nontarget organisms.

Investigation of the presence and endocrine activities of pesticides found in wastewater effluent using yeast-based bioassays.

This study investigated the presence of a variety of pesticides (herbicides, fungicides, and insecticides) in effluent of three wastewater treatment plants as well as their endocrine activities using yeast-based in vitro assays. Although the presence of these contaminants of emerging concern is frequently reported to be present throughout the environment, their presence in wastewater treatment plants has been seldom studied. Of the 18 compounds investigated in this study, imidacloprid was the only compound not detected in all three WWTPs. Concentrations measured ranged from 3ng/L to 27µg/L for fluconazole. The yeast estrogenic and yeast androgenic screen assays were performed on target compounds in order to investigate their endocrine disruption and potential environmental risks to receiving waters. It was found that of the 14 compounds investigated 12 showed either antiestrogenic or antiandrogenic activity and seven compounds showed pleiotropic effects. In addition to confirming endocrine activities of pesticides using the yeast-based assays this study is one of the first to report activities for novel compounds including three neonicotinoids.

Development of a Facile and High-Throughput Bioluminescence Assay Using Vibrio fischeri to Determine the Chronic Toxicity of Contaminated Samples.

Chronic toxicity testing using the luminescent bacterium, Vibrio fischeri, has recently been demonstrated to be a suitable bioassay for water quality monitoring. The toxicity evaluation is typically based on determining the EC50 at specific time points which may lead to overlooking the dynamic nature of luminescence response and limits information regarding the possible mechanisms of action of target compounds. This study investigated various approaches (standard, integral, and luminescence rate inhibition) to evaluate the chronic toxicity of three target compounds (atrazine, trimethoprim, and acetamiprid) using a 96-well plate based method. The chronic toxicity assay and the methods used for EC50 calculation provided in this work resulted in a high-throughput method of chronic toxicity testing and indicated lower EC50 than the values provided by the standard short term methods, indicating higher toxicity. This study emphasizes the need for additional chronic toxicity testing to further evaluate the toxicity of compounds or unknown samples.