Journal of water and health最新文献

Wastewater surveillance of SARS-CoV-2 has been used around the world to supplement clinical testing data for situational awareness of COVID-19 disease trends. Many regions of the world lack centralized wastewater collection and treatment infrastructure, which presents additional considerations for wastewater surveillance of SARS-CoV-2, including environmental decay of the RT-qPCR gene targets used for quantification of SARS-CoV-2 virions. Given the role of sunlight in the environmental decay of RNA, we evaluated sunlight photolysis kinetics of the N1 gene target in heat-inactivated SARS-CoV-2 with a solar simulator under laboratory conditions. Insignificant photolysis of the N1 target was observed in a photosensitizer-free matrix. Conversely, significant decay of the N1 target was observed in wastewater at a shallow depth (<1 cm). Given that sunlight irradiance is affected by several environmental factors, first-order decay rate models were used to evaluate the effect of water column depth, time of the year, and latitude on decay kinetics. Decay rate constants were found to decrease significantly with greater depth of the well-mixed water column, at high latitudes, and in the winter. Therefore, sunlight-mediated decay of the N1 gene target is likely to be minimal, and is unlikely to confound results from wastewater-based epidemiology programs utilizing wastewater-impacted surface waters.

This study retains the basic structure of DRASTIC model and obtains more specific evaluation results by adding land-use type and groundwater resource yield parameters, modifying the rating scale and weight of nine parameters. Comparison of the modified DRASTIC-LY vulnerability map with the map of the original DRASTIC-LY method revealed differences in 40.49% of the study area. The risk map shows that the very high vulnerability area decreased from 2.79 to 1.67%, while the high vulnerability area increased from 18.70 to 28.86%. Areas with low vulnerability increased by 10.15%, while areas with medium vulnerability decreased by 15.01%. The areas with very high groundwater vulnerability are mainly distributed in the Hanbin area on the north bank of the Han River, the areas with high are mainly concentrated on both sides of the Fujia River, while the areas with low are distributed in most areas in the west of the basin. The Pearson's correlation factor was 0.0583 in the original DRASTIC model, 0.1113 in the DRASTIC-LY method and 0.8291 in the modified DRASTIC-LY model, which indicated that the revised DRASTIC-LY model was more appropriate than the original model. The results can help the government with the protection of water resources.

Ultraviolet light-emitting diodes (UV-LED) can be a good option for disinfecting water in small and decentralized facilities. A flow-through UV-LED disinfection module was evaluated at three remote locations in Japan. The disinfection efficiency of the module was monitored for over one year, targeting indigenous Escherichia coli, total coliforms, standard plate count, and heterotrophic plate count (HPC) bacteria. The physicochemical parameters of the source water, including UV transmittance (UVT), were also monitored to understand their natural fluctuation and impacts on UV disinfection. Overall, the UV-LED module showed efficient disinfection at all locations, achieving 2.7 log inactivation of E. coli at 30 L/min in a community-based water supply. HPC inactivation did not significantly differ among the three test sites (p > 0.01). One test site experienced a decrease in HPC inactivation after 10 months, whereas the other two sites did not show performance deterioration after one year. HPC inactivation was not correlated with the UVT of source water at any location, implying the difficulty to use UVT as a single parameter to predict disinfection efficiency in practical applications. This study demonstrates the effectiveness of UV-LED technology for water disinfection in small and decentralized water supply systems.

SARS-CoV-2 wastewater surveillance (WWS) at wastewater treatment plants (WWTPs) can reveal sewered community COVID-19 prevalence. For unsewered areas using septic tank systems (STSs) or holding tanks, how to conduct WWS remains unexplored. Here, two large STSs serving Zuma Beach (Malibu, CA) were studied. Supernatant and sludge SARS-CoV-2 concentrations from the directly-sampled STSs parameterized a dynamic solid-liquid separation, mass balance-based model for estimating the infection rate of users. Pumped septage before hauling and upon WWTP disposal was also sampled and assessed. Most (96%) STS sludge samples contained SARS-CoV-2 N1 and N2 genes, with concentrations exceeding the supernatant and increasing with depth while correlating with total suspended solids (TSS). The trucked septage contained N1 and N2 genes which decayed (coefficients: 0.09-0.29 h^-1) but remained detectable. Over approximately 5 months starting in December 2020, modeled COVID-19 prevalence estimations among users ranged from 8 to 18%, mirroring a larger metropolitan area for the first 2 months. The approaches herein can inform public health intervention and augment conventional WWS in that: (1) user infection rates for communal holding tanks are estimable and (2) pumped and hauled septage can be assayed to infer where disease is spreading in unsewered areas.

Legionnaires' disease (LD) is a severe pneumonia mainly caused by the bacterium Legionella pneumophila. Although many environmental sources of LD have been described, the sources of the majority of non-outbreak LD cases have not been identified. In several outbreaks in the Netherlands, wastewater treatment plants (WWTPs) were identified as the most likely source of infection. In this study, four criteria for Legionella growth and emission to air and surface waters were selected based on the literature and a risk matrix was drafted. An inventory was made of all WWTPs and their characteristics in the Netherlands. The risk matrix was applied to identify WWTPs at risk for Legionella growth and emission. Wastewater was collected at WWTPs with moderate to high risk for Legionella growth and emission. In 18% of the sampled WWTPs, Legionella spp. was detected using culture methods. The presented risk matrix can be used to assess the risks of Legionella growth and emission for WWTPs and support surveillance by prioritizing WWTPs. When Legionella is detected in the wastewater, it is recommended to take action to prevent emission to air or discharge on surface waters and, if possible, reduce the Legionella concentration.

Antibiotic residues in the environment threaten soil and aquatic organisms and human and livestock health through the building of antimicrobial resistance. Manure spreading associated with animal agriculture is one source of environmental antibiotic residues. To better understand the risk of contamination, we studied the adsorption of erythromycin, a model macrolide antibiotic used across human and animal medicine. We conducted a series of equilibrium batch experiments to determine the kinetics and extent of adsorption and a continuous-flow column adsorption experiment to observe non-equilibrium adsorption patterns. We determined that the adsorption equilibration time to soil was approximately 72 h in our batch experiments. Erythromycin adsorbed to soil relatively strongly (K = 8.01 × 10^-2 L/mg; q_max = 1.53 × 10^-3 mg/mg), adsorbed to the soil in the presence of manure with less affinity (K = 1.99 × 10^-4 L/mg) at a soil: manure ratio of 10:1 by mass, and did not adsorb to manure across the solid ratios tested. We observed multi-phased adsorption of erythromycin to the soil during the non-equilibrium column experiment, which was largely absent from the treatments with both soil and manure present. These results suggest that erythromycin is more mobile in the environment when introduced with manure, which is likely the largest source of agriculturally sourced environmental antibiotics.

Recent MPOX viral resurgences have mobilized public health agencies around the world. Recognizing the significant risk of MPOX outbreaks, large-scale human testing, and immunization campaigns have been initiated by local, national, and global public health authorities. Recently, traditional clinical surveillance campaigns for MPOX have been complemented with wastewater surveillance (WWS), building on the effectiveness of existing wastewater programs that were built to monitor SARS-CoV-2 and recently expanded to include influenza and respiratory syncytial virus surveillance in wastewaters. In the present study, we demonstrate and further support the finding that MPOX viral fragments agglomerate in the wastewater solids fraction. Furthermore, this study demonstrates that the current, most commonly used MPOX assays are equally effective at detecting low titers of MPOX viral signal in wastewaters. Finally, MPOX WWS is shown to be more effective at passively tracking outbreaks and/or resurgences of the disease than clinical testing alone in smaller communities with low human clinical case counts of MPOX.

By community intervention in 14 non-disinfecting municipal water systems, we quantified sporadic acute gastrointestinal illness (AGI) attributable to groundwater. Ultraviolet (UV) disinfection was installed on all supply wells of intervention communities. In control communities, residents continued to drink non-disinfected groundwater. Intervention and control communities switched treatments by moving UV disinfection units at the study midpoint (crossover design). Study participants (n = 1,659) completed weekly health diaries during four 12-week surveillance periods. Water supply wells were analyzed monthly for enteric pathogenic viruses. Using the crossover design, groundwater-borne AGI was not observed. However, virus types and quantity in supply wells changed through the study, suggesting that exposure was not constant. Alternatively, we compared AGI incidence between intervention and control communities within the same surveillance period. During Period 1, norovirus contaminated wells and AGI attributable risk from well water was 19% (95% CI, -4%, 36%) for children <5 years and 15% (95% CI, -9%, 33%) for adults. During Period 3, echovirus 11 contaminated wells and UV disinfection slightly reduced AGI in adults. Estimates of AGI attributable risks from drinking non-disinfected groundwater were highly variable, but appeared greatest during times when supply wells were contaminated with specific AGI-etiologic viruses.

The European Union currently has no specific regulations on fungi in water. The only country where fungi are listed as the parameter is Sweden, with the maximal number of 100 CFU per 100 mL. The present study thus compared culturable mycobiota from Swedish drinking water with Slovenian, which has no specific requirements for fungi. Fungi were isolated with up to 38 CFU/L from 75% of Swedish samples. The most common were the genera Varicosporellopsis (27.3%), Paracremonium (14.5%), and black yeasts Cadophora, Cyphellophora, and Exophiala (18.2%). Using the same sampling and isolation methods, 90% of tap water samples in Slovenia were positive for fungi, with Aspergillus spp. (46%), Aureobasidium melanogenum (36%), and Exophiala spp. (24%) being the most common. The observed differences between countries are likely the consequence of geographical location, the use of different raw water sources, and water treatment methods. However, the core species and emerging fungi Aspergillus fumigatus, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Bisifusarium dimerum, and Rhodotorula mucilaginosa were isolated in both studies. These findings point out the relevance of tracking the presence of emerging fungi with known effects on health in drinking water and encourage further studies on their transmission from raw water sources to the end-users.

The dissemination of antimicrobial resistance in the environment is an emerging global health problem. Wastewater treatment effluent and combined sewer overflows (CSOs) are major sources of antimicrobial resistance in urban rivers. This study aimed to clarify the effect of municipal wastewater treatment effluent and CSO on antimicrobial resistance genes (ARGs), mobile gene elements, and the microbial community in an urban river. The ARG abundance per 16S-based microbial population in the target river was 0.37-0.54 and 0.030-0.097 during the CSO event and dry weather, respectively. During the CSO event, the antimicrobial resistome in the river shifted toward a higher abundance of ARGs to clinically important drug classes, including macrolide, fluoroquinolone, and β-lactam, whereas ARGs to sulfonamide and multidrug by efflux pump were relatively abundant in dry weather. The abundance of intI1 and tnpA genes were highly associated with the total ARG abundance, suggesting their potential application as an indicator for estimating resistome contamination. Increase of prophage during the CSO event suggested that impact of CSO has a greater potential for horizontal gene transfer (HGT) via transduction. Consequently, CSO not only increases the abundance of ARGs to clinically important antimicrobials but also possibly enhances potential of HGT in urban rivers.