The Water Quality in Rio Highlights the Global Public Health Concern Over Untreated Sewage

Epidemiological surveillance and infectious disease outbreaks during mass international summertime sports gatherings: A narrative review

The XXXIIIrd Paris Summer Olympics followed by the XVIIth Paralympics Games will take place in France, predominantly in and around Paris, from July 26 to September 8, 2024. Public health stakeholders and decision-makers are called upon to set up or strengthen surveillance systems in areas hosting Olympic or Paralympic Games (OPGs) or large-scale international competitions, the objective being to detect and manage outbreaks should they occur during that period. We undertook a narrative review of the literature so as to identify major reported infectious disease outbreaks linked with or during OPGs / international sporting events during warm seasons. Our review found that since 1992, Summer Olympic and Paralympic games and international football competitions have been associated with sporadic cases of infectious diseases, principally respiratory, gastrointestinal/foodborne, but not with any major communicable or other infectious disease outbreak. Communicable disease risks should be assessed for the population taken as a whole, an integrated ecosystem with several population compartments potentially exchanging pathogens among one another. Although the Games afford an opportunity to federate or invent new surveillance systems to fill a gap, surveillance should be based on existing medical and laboratory systems, proven tools reinforced with the necessary human and financial resources. The performance of the public health surveillance system is ultimately predicated on trust on the part of participating clinicians, policymakers and international partners.

β-D-glucuronidase activity triggered monitoring of fecal contamination using microbial and chemical source tracking markers at drinking water intakes

Intense rainfall and snowmelt events may affect the safety of drinking water, as large quantities of fecal material can be discharged from storm or sewage overflows or washed from the catchment into drinking water sources. This study used β-d-glucuronidase activity (GLUC) with microbial source tracking (MST) markers: human, bovine, porcine mitochondrial DNA markers (mtDNA) and human-associated Bacteroidales HF183 and chemical source tracking (CST) markers including caffeine, carbamazepine, theophylline and acetaminophen, pathogens (Giardia, Cryptosporidium, adenovirus, rotavirus and enterovirus), water quality indicators (Escherichia coli, turbidity) and hydrometeorological data (flowrate, precipitation) to assess the vulnerability of 3 drinking water intakes (DWIs) and identify sources of fecal contamination. Water samples were collected under baseline, snow and rain events conditions in urban and agricultural catchments (Québec, Canada). Dynamics of E. coli, HF183 and WWMPs were similar during contamination events, and concentrations generally varied over 1 order of magnitude during each event. Elevated human-associated marker levels during events demonstrated that urban DWIs were impacted by recent contamination from an upstream municipal water resource recovery facility (WRRF). In the agricultural catchment, mixed fecal pollution was observed with the occurrences and increases of enteric viruses, human bovine and porcine mtDNA during peak contaminating events. Bovine mtDNA qPCR concentrations were indicative of runoff of cattle-derived fecal pollutants to the DWI from diffuse sources following rain events. This study demonstrated that the suitability of a given MST or CST indicator depend on river and catchment characteristics. The sampling strategy using continuous online GLUC activity coupled with MST and CST markers analysis was a more reliable source indicator than turbidity to identify peak events at drinking water intakes.

Ecological Risk Analysis for Benzalkonium Chloride, Benzethonium Chloride, and Chloroxylenol in US Disinfecting and Sanitizing Products

Use of three topical antiseptic compounds-benzalkonium chloride (BAC), benzethonium chloride (BZT), and chloroxylenol (PCMX)-has recently increased because of the phaseout of other antimicrobial ingredients (such as triclosan) in soaps and other disinfecting and sanitizing products. Further, use of sanitizing products in general increased during the coronavirus (COVID-19) pandemic. We assessed the environmental safety of BAC, BZT, and PCMX based on best available environmental fate and effects data from the scientific literature and privately held sources. The ecological exposure assessment focused on aquatic systems receiving effluent from wastewater-treatment plants (WWTPs) and terrestrial systems receiving land-applied WWTP biosolids. Recent exposure levels were characterized based on environmental monitoring data supplemented by modeling, while future exposures were modeled based on a hypothetical triclosan replacement scenario. Hazard profiles were developed based on acute and chronic studies examining toxicity to aquatic life (fish, invertebrates, algae, vascular plants) and terrestrial endpoints (plants, soil invertebrates, and microbial functions related to soil fertility). Risks to higher trophic levels were not assessed because these compounds are not appreciably bioaccumulative. The risk analysis indicated that neither BZT nor PCMX in any exposure media is likely to cause adverse ecological effects under the exposure scenarios assessed in the present study. Under these scenarios, total BAC exposures are at least three times less than estimated effect thresholds, while margins of safety for freely dissolved BAC are estimated to be greater than an order of magnitude. Because the modeling did not specifically account for COVID-19 pandemic-related usage, further environmental monitoring is anticipated to understand potential changes in environmental exposures as a result of increased antiseptic use. The analysis presented provides a framework to interpret future antiseptic monitoring results, including monitoring parameters and modeling approaches to address bioavailability of the chemicals of interest. Environ Toxicol Chem 2022;41:3095-3115. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Advances in Technological Research for Online and In Situ Water Quality Monitoring—A Review

Monitoring water quality is an essential tool for the control of pollutants and pathogens that can cause damage to the environment and human health. However, water quality analysis is usually performed in laboratory environments, often with the use of high-cost equipment and qualified professionals. With the progress of nanotechnology and the advance in engineering materials, several studies have shown, in recent years, the development of technologies aimed at monitoring water quality, with the ability to reduce the costs of analysis and accelerate the achievement of results for management and decision-making. In this work, a review was carried out on several low-cost developed technologies and applied in situ for water quality monitoring. Thus, new alternative technologies for the main physical (color, temperature, and turbidity), chemical (chlorine, fluorine, phosphorus, metals, nitrogen, dissolved oxygen, pH, and oxidation–reduction potential), and biological (total coliforms, Escherichia coli, algae, and cyanobacteria) water quality parameters were described. It was observed that there has been an increase in the number of publications related to the topic in recent years, mainly since 2012, with 641 studies being published in 2021. The main new technologies developed are based on optical or electrochemical sensors, however, due to the recent development of these technologies, more robust analyses and evaluations in real conditions are essential to guarantee the precision and repeatability of the methods, especially when it is desirable to compare the values with government regulatory standards.

Toward shotgun metagenomic approaches for microbial source tracking sewage spills based on laboratory mesocosms

Little is known about the genomic diversity of the microbial communities associated with raw municipal wastewater (sewage), including whether microbial populations specific to sewage exist and how such populations could be used to improve source attribution and apportioning in contaminated waters. Herein, we used the influent of three wastewater treatment plants in Atlanta, Georgia (USA) to perturb laboratory freshwater mesocosms, simulating sewage contamination events, and followed these mesocosms with shotgun metagenomics over a 7-day observational period. We describe 15 abundant non-redundant bacterial metagenome-assembled genomes (MAGs) ubiquitous within all sewage inocula yet absent from the unperturbed freshwater control at our analytical limit of detection. Tracking the dynamics of the populations represented by these MAGs revealed varied decay kinetics, depending on (inferred) phenotypes, e.g., anaerobes decayed faster than aerobes under the well-aerated incubation conditions. Notably, a portion of these populations showed decay patterns similar to those of common markers, Enterococcus and HF183. Despite the apparent decay of these populations, the abundance of β-lactamase encoding genes remained high throughout incubation relative to the control. Lastly, we constructed genomic libraries representing several different fecal sources and outline a bioinformatic approach which leverages these libraries for identifying and apportioning contamination signal among multiple probable sources using shotgun metagenomic data.

Multiscale land use impacts on water quality: Assessment, planning, and future perspectives in Brazil

Brazil contains the largest volume of freshwater of any nation in the world; however, this essential natural resource is threatened by rapid increases in water consumption and water quality degradation, mainly as a result of anthropogenic pressures. Declining water quality has become an increasingly more significant global concern as economic activities and human populations expand and climate change markedly alters hydrological cycles. Changes in land-use/land-cover (LULC) pattern have been recognized as a major driver of water quality degradation, however different LULC types and intensities affect water quality in different ways. In addition, the relationships between LULC and water quality may differ for different spatial and temporal scales. The increase in deforestation, agricultural expansion, and urban sprawl in Brazil highlights the need for water quality protection to ensure immediate human needs and to maintain the quality of water supplies in the long-term. Thus, this manuscript provides an overview of the relationships between LULC and water quality in Brazil, aiming at understanding the effects of different LULC types on water quality, how spatial and temporal scales contribute to these effects, and how such knowledge can improve watershed management and future projections. In general, agriculture and urban areas are the main LULCs responsible for water quality degradation in Brazil. However, although representing a small percentage of the territory, mining has a high impact on water quality. Water quality variables respond differently at different spatial scales, so spatial extent is an important aspect to be considered in studies and management. LULC impacts on water quality also vary seasonally and lag effects mean they take time to occur. Forest restoration can improve water quality and multicriteria evaluation has been applied to identify priority areas for forest restoration and conservation aiming at protecting water quality, but both need further exploration. Watershed modelling has been applied to simulate future impacts of LULC change on water quality, but data availability must be improved to increase the number, locations and duration of studies. Because of the international nature of watersheds and the consistent relationships between land use and water quality in Brazil, we believe our results will also aid water management in other countries.

A critical analysis of recreational water guidelines developed from temperate climate data and applied to the tropics

Recreational water epidemiology studies are rare in settings with minimal wastewater treatment where risk may be highest, and in tropical settings where warmer temperature influences the ecology of fecal indicator bacteria commonly used to monitor recreational waters. One exception is a 1999 study conducted in São Paulo Brazil. We compared the risk and exposure characteristics of these data with those conducted in the United Kingdom (UK) in the early 1990s that are the basis of the World Health Organization's (WHO) guidelines on recreational water risks. We then developed adjusted risk difference models (excess gastrointestinal illness per swimming event) for children (<10 years of age) and non-children (≥10 years of age) across five Brazil beaches. We used these models along with beach water quality data from 2004 to 2015 to assess spatial and temporal trends in water quality and human risk. Risk models indicate that children in Brazil have as much as two times the risk of gastrointestinal illness than non-children. In Brazil, 11.8% of the weekly water samples from 2004 to 2015 exceeded 158 enterococci CFU/100 ml, the highest level of fecal streptococci concentration measured in the UK study. Risks associated with these elevated levels equated to median NEEAR-Gastrointestinal Illness (NGI) risks of 53 and 96 excess cases per 1000 swimmers in non-children and children, respectively. Two of the five beaches appear to drive the overall elevated NGI risks seen during this study. Distinct enteric pathogen profiles that exist in tropical settings as well as in settings with minimal wastewater treatment highlight the importance of regionally specific guideline development.

Fecal pollution: new trends and challenges in microbial source tracking using next-generation sequencing

In this minireview, we expand upon traditional microbial source tracking (MST) methods by discussing two recently developed, next-generation-sequencing (NGS)-based MST approaches to identify sources of fecal pollution in recreational waters. One method defines operational taxonomic units (OTUs) that are specific to a fecal source, e.g., humans and animals or shared among multiple fecal sources to determine the magnitude and likely source association of fecal pollution. The other method uses SourceTracker, a program using a Bayesian algorithm, to determine which OTUs have contributed to an environmental community based on the composition of microbial communities in multiple fecal sources. Contemporary NGS-based MST tools offer a promising avenue to rapidly characterize fecal source contributions for water monitoring and remediation efforts at a broader and more efficient scale than previous molecular MST methods. However, both NGS methods require optimized sequence processing methodologies (e.g. quality filtering and clustering algorithms) and are influenced by primer selection for amplicon sequencing. Therefore, care must be taken when extrapolating data or combining datasets. Furthermore, traditional limitations of library-dependent MST methods, including differential decay of source material in environmental waters and spatiotemporal variation in source communities, remain to be fully understood. Nevertheless, increasing use of these methods, as well as expanding fecal taxon libraries representative of source communities, will help improve the accuracy of these methods and provide promising tools for future MST investigations.

Enteric viruses and adenovirus diversity in waters from 2016 Olympic venues

Rio de Janeiro's inner and coastal waters are heavily impacted by human sewage pollution for decades. Enteric viruses, including human adenoviruses (HAdV), human enterovirus (EV), group A rotavirus (RV) and hepatitis A virus (HAV) are more likely to be found in contaminated surface waters. The present work aimed to assess the frequency and loads of EV, HAdV-C and -F species, RV and HAV in sand and water samples from venues used during the 2016 Summer Olympics and by tourists attending the event. Sixteen monthly collections were carried out from March 2015 to July 2016 in 12 different sites from Rio de Janeiro, Brazil. Total and thermotolerant coliform counting was performed along molecular detection of virus was performed using quantitative polymerase chain reaction (qPCR). Analyses of all samples were further investigated by integrated cell culture PCR to check about the presence of HAdV infectious virus particles. The results show that 95.9% of water samples showed contamination with at least one type of virus. Regarding the viruses individually (% for water and sand respectively): HAdV-C (93.1%-57.8%), HAdV-F (25.3%-0%), RV (12.3%-4.4%), EV (26.7%-8.8%) and HAV (0%). The viral loads ranged from 10³gc/L up to 10⁹gc/L (water), and 10³gc/g to 10⁶gc/g (sand). In the phylogenetic tree, were classified into four main clusters, referring to species C, D, F and BAdV. And up to 90% of sites studied presented at least once presence of infectious HAdV-C. The most contaminated points were the Rodrigo de Freitas Lagoon, where Olympic rowing took place, and the Marina da Glória, the starting point for the sailing races, demonstrating serious problem of fecal contamination of water resources and threatens the health of Olympic athletes, tourists and residents.