Ministry of the Environment

The wastewater viral activity level (WVAL) was developed by the United States Centers for Disease Control and Prevention (US CDC) as a standardized metric to aggregate SARS-CoV-2 wastewater data, enabling the assessment of infection levels and trends at state/territorial, regional and national scales. This approach also facilitates comparative analysis of SARS-CoV-2 prevalence across regions. In this study, we developed and evaluated graphical methods to integrate the WVAL metric into interpretable visualizations for public health decision-making. Preliminary analysis demonstrated that WVAL values correlated strongly with clinical case counts, supporting its role as a confirmatory epidemiological measure. The WVAL framework provided a linear quantification method, allowing for the comparison of regional variations in infection patterns. This study leveraged data from the Ontario Wastewater Surveillance Initiative (Ontario WSI), which included over 100 sampling sites across seven geographical regions. Weekly mean WVAL values were computed for each site and aggregated at regional and provincial levels. In total, 59 sites contributed to the provincial WVAL calculation. The computational aggregation method followed the US CDC WVAL approach and was generally comparable to the Public Health Ontario (PHO) aggregation method, with the notable improvement of incorporating a linear level scale. Overall, this study demonstrated that WVAL effectively quantified SARS-CoV-2 differences at a public health regional scale. The WVAL metric proved to be a robust epidemiological tool, complementing other surveillance measures to support public health decision-making. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by the Ontario Wastewater Surveillance Initiative of the Ontario Ministry of the Environment, Conservation and Parks (MECP). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors

Morphological abnormalities in amphibians are commonly associated with anthropogenic activity, although little baseline information on the prevalence of abnormalities in uncontaminated environments exist. Here, we leverage a 12-year study of spotted salamanders ( Ambystoma maculatum (Shaw, 1802)) in an uncontaminated ecosystem in Algonquin Provincial Park, Canada, to estimate abnormality rates and explore how abnormalities affect fitness-related traits. Annual abnormality rates estimated from drift fence data ranged from 4.3% to 5.8% of individuals sampled. Abnormality rates from aquatic trapping between 2008 and 2019 varied from 1.2% to 16.7%, where temporal increases in abnormality rates were observed. We also performed a targeted, systematic literature survey and found that Caudata exhibited a slightly higher abnormality prevalence than Anura, and that the baseline frequency of abnormalities described at our drift fence site is slightly lower than rates reported in the literature (8.1%, 95% CI, 4.76%–13.3%). Salamanders with abnormalities exhibited a slightly, but not significantly, higher body condition and a significantly earlier arrival date at the breeding site, both of which are traits typically associated with high-fitness individuals. Our study suggests that abnormalities have detectable phenotypic consequences, and underlines the need for temporal sampling efforts to provide ranges of baseline abnormality rates, rather than a point estimate.

Air samples were collected from six locations during the periods of February, 2011–March, 2012 in Beijing city. Samples were analyzed using HRGC-HRMS according to HJ 77. 2-2008. The concentrations, congener profiles, seasonal variation, spatial distribution, and sources identified were investigated. The mass concentrations of 2,3,7,8-substituted PCDD/Fs is 1750 to 10380 fg/m3 with an average of 3670 fg/m3. The highest concentration was observed at site DS in February 2011 and the lowest was at site NS in July 2011. The TEQ concentrations of PCDD/Fs ranged from 35.0 to 751 fg I-TEQ/m3, with an average of 251 fg I-TEQ/m3. The dominant contributor to total TEQ value is 2,3,7,8-PeCDFs, with an average contribution of 40

N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q), the tire rubber-derived transformation product of 6PPD, was recently discovered to cause the acute mortality of coho salmon (Oncorhynchus kisutch). Aiming to identify a potential nontoxic replacement antioxidant for 6PPD, we herein synthesized seven PPD-quinones with distinct side chains to investigate their structure-related toxicities in rainbow trout (Oncorhynchus mykiss). While 6PPD-Q exerted strong toxicity (96 h LC50 = 0.64 µg/L), toxicity was not observed for six other PPD-quinones despite their similar structures. The fish tissue concentrations of 6PPD-Q after exposure (0.8 µg/L) were comparable to the other PPD-quinones, which indicated that bioaccumulation levels were not the reason for the selective toxicity of 6PPD-Q. Hydroxylated PPD-quinones were detected as the predominant metabolites in fish tissue. Interestingly, a single major aromatic hydroxylation metabolite was detected for nontoxic PPD-quinones, but two abundant OH-6PPD-Q isomers were detected. MS2 spectra confirmed that hydroxylation occurred on the alkyl side chain for one isomer. Based on this fact, we suggested a ‘dual-action’ model wherein OH-6PPD-Q was generated by an enzyme with a high regioselectivity, which further attacks an unknown protein to cause lethality. This study reported the selective toxicity of 6PPD-Q and pinpointed the possibility for other PPDs to be applied as safe replacements of 6PPD.

Since the 1950s, the widespread application of road salt for winter road maintenance and safety in cold regions has led to increased conductivity levels in many freshwater systems. Salting practices have adversely affected freshwater biota; however, the magnitude of ecological impacts may vary by species and ecosystem. Here, we examine diatom assemblage changes during the past ∼200 years from the sedimentary records of five impacted lakes (measured specific conductance values of 149–350 µS·cm−1) and a reference lake (18 µS·cm−1) located in the Muskoka River Watershed, south-central Ontario, Canada. Diatom compositional changes in the road-salt-impacted sites were consistent with increasing conductivity and increased diatom-inferred (DI)-conductivity was evident during the latter half of the 20th century in the impacted lakes, concurrent with known road-salt application. The strongest predictor of DI-conductivity changes among the six lakes was the kilometre equivalents of roads within the watershed (i.e., kilometres of road × number of lanes). Similar to changes observed in a previous study focusing on cladoceran assemblages, we conclude that even modest applications of road salt can affect diatom assemblages in softwater lakes.