Wastewater treatment plants (WWTPs), linking human fecal residues and the environment, are considered as hotspots for the spread of antimicrobial resistance (AMR). In order to evaluate the role of ...WWTPs and underlying operational parameters for the removal of AMR, the presence and removal efficiency of a selected set of 6 antimicrobial resistance genes (ARGs) and 2 mobile genetic elements (MGEs) was evaluated by means of qPCR in influent and effluent samples from 62 Dutch WWTPs. The role of possible factors impacting the concentrations of ARGs and MGEs in the influent and their removal was identified through statistical analysis. ARGs and the class I integron-integrase gene (intI1) were, on average, removed to a similar extent (1.76 log reduction) or better (+0.30–1.90 logs) than the total bacteria (measured as 16S rRNA gene). In contrast, broad-host-range plasmids (IncP-1) had a significantly increased (p < 0.001) relative abundance after treatment. The presence of healthcare institutions in the area served did only slightly increase the concentrations of ARGs or MGEs in influent. From the extended panel of operational parameters, rainfall, increasing the hydraulic load of the plant, most significantly (p < 0.05) affected the treatment efficiency by decreasing it on average −0.38 logs per time the flow exceeded the average daily flow. Our results suggest that overall, WWTP treatments do not favor the proliferation of the assessed resistance genes but might increase the relative abundance of broad-host-range plasmids of the IncP-1 type.
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•Sulfonamide (sul1) and macrolide (ermB) ARGs are predominant ARGs in the influent.•Healthcare institutions in the catchment didn't increase the influent's ARGs loads.•WWTP treatment reduced ARGs by 1.8–2.7 logs.•Relative abundance of IncP-1 plasmids was increased (p < 0.001) after WWTP treatment.•Rainfall increasing the WWTP hydraulic load significantly reduced the removal of ARGs.
Temperature is considered as the major factor determining virus inactivation in the environment. Food industries, therefore, widely apply temperature as virus inactivating parameter. This review ...encompasses an overview of viral inactivation and virus genome degradation data from published literature as well as a statistical analysis and the development of empirical formulae to predict virus inactivation. A total of 658 data (time to obtain a first log10 reduction) were collected from 76 published studies with 563 data on virus infectivity and 95 data on genome degradation. Linear model fitting was applied to analyse the effects of temperature, virus species, detection method (cell culture or molecular methods), matrix (simple or complex) and temperature category (<50 and ≥50°C). As expected, virus inactivation was found to be faster at temperatures ≥50°C than at temperatures <50°C, but there was also a significant temperature–matrix effect. Virus inactivation appeared to occur faster in complex than in simple matrices. In general, bacteriophages PRD1 and PhiX174 appeared to be highly persistent whatever the matrix or the temperature, which makes them useful indicators for virus inactivation studies. The virus genome was shown to be more resistant than infectious virus. Simple empirical formulas were developed that can be used to predict virus inactivation and genome degradation for untested temperatures, time points or even virus strains.
The quality of drinking water in the Netherlands has to comply with the Dutch Drinking Water Directive: less than one infection in 10,000 persons per year may occur due to consumption of unboiled ...drinking water. Since virus concentrations in drinking waters may be below the detection limit but entail a public health risk, the infection risk from drinking water consumption requires the assessment of the virus concentrations in source waters and of the removal efficiency of treatment processes. In this study, samples of source waters were taken during 4 years of regular sampling (1999 to 2002), and enteroviruses, reoviruses, somatic phages, and F-specific phages were detected in 75% (range, 0.0033 to 5.2 PFU/liter), 83% (0.0030 to 5.9 PFU/liter), 100% (1.1 to 114,156 PFU/liter), and 97% (0.12 to 14,403 PFU/liter), respectively, of 75 tested source water samples originating from 10 locations for drinking water production. By endpoint dilution reverse transcription-PCR (RT-PCR), 45% of the tested source water samples were positive for norovirus RNA (0.22 to 177 PCR-detectable units PDU/liter), and 48% were positive for rotavirus RNA (0.65 to 2,249 PDU/liter). Multiple viruses were regularly detected in the source water samples. A significant correlation between the concentrations of the two phages and those of the enteroviruses could be demonstrated. The virus concentrations varied greatly between 10 tested locations, and a seasonal effect was observed. Peak concentrations of pathogenic viruses occur in source waters used for drinking water production. If seasonal and short-term fluctuations coincide with less efficient or failing treatment, an unacceptable public health risk from exposure to this drinking water may occur.
Peatlands play an important role as carbon pools, storing a third of the world's soil carbon. However, peatlands in Southeast Asia have suffered from depletion due to economic pressure and the demand ...for natural resources, often caused by land use changes and fires. Usually, land preparation requires drainage and fires, resulting in major greenhouse gas (GHG) emissions into the atmosphere. In this work, we propose a general equation to estimate GHG emissions from fires on peatlands. The contribution of each parameter to the variance of the estimated GHG emissions was also evaluated. We used Monte Carlo simulation, meta‐analyses, and an analytical expression of variance. GHG emissions of a single fire episode were estimated at 842 Mg ha−1 CO2 eq. with a standard deviation of 466 Mg ha−1 CO2 eq. The parameter contributing most to variance was the depth of burn, at 94.2%, followed by bulk density, at 5.5%, and emission factors, at 0.3%. Our estimated GHG emissions were close to the amount estimated from the default values provided by the IPCC, strengthening confidence in the IPCC methodology. When the depth of burn was assessed by remote sensing, the parameter that most contributed to variance became the fire‐damaged area, followed by the depth of burn. The contribution of each parameter to variance, as estimated in this study, made it possible to prioritize the effort in uncertainty reduction. Combining Monte Carlo simulation and an analytical expression of variance could be a promising way of obtaining more reliable confidence intervals.
Key Points
Greenhouse gas (GHG) emissions from peat combustion due to prospective wildfires in Indonesia were estimated at 842 ± 466 Mg ha−1 CO2 eq
Uncertainties were attributed at 94.2% to depth of burn in a prospective approach, and to fire‐damaged area and bulk density in a retrospective approach
Default values of the parameters to estimate GHG emissions from peat combustion were proposed to improve the accuracy of future estimates
The water in the canals and some recreational lakes in Amsterdam is microbiologically contaminated through the discharge of raw sewage from houseboats, sewage effluent, and dog and bird feces. ...Exposure to these waters may have negative health effects. During two successive 1-year study periods, the water quality in two canals (2003 to 2004) and five recreational lakes (2004 to 2005) in Amsterdam was tested with regard to the presence of fecal indicators and waterborne pathogens. According to Bathing Water Directive 2006/7/EC, based on Escherichia coli and intestinal enterococcus counts, water quality in the canals was poor but was classified as excellent in the recreational lakes. Campylobacter, Salmonella, Cryptosporidium, and Giardia were detected in the canals, as was rotavirus, norovirus, and enterovirus RNA. Low numbers of Cryptosporidium oocysts and Giardia cysts were detected in the recreational lakes, despite compliance with European bathing water legislation. The estimated risk of infection with Cryptosporidium and Giardia per exposure event ranged from 0.0002 to 0.007% and 0.04 to 0.2%, respectively, for occupational divers professionally exposed to canal water. The estimated risk of infection at exposure to incidental peak concentrations of Cryptosporidium and Giardia may be up to 0.01% and 1%, respectively, for people who accidentally swallow larger volumes of the canal water than the divers. Low levels of viable waterborne pathogens, such as Cryptosporidium and Giardia, pose a possible health risk from occupational, accidental, and recreational exposure to surface waters in Amsterdam.
Abstract Hematic administration of bone marrow-derived mesenchymal stem cells (MSCs) in acute ischemic stroke may not only be an effective reparative treatment but also a brain protective therapy ...that improves neurological recovery. Our purpose was to study whether either i.v. or intracarotid (i.c.) administration of allogenic MSCs during the acute phase were effective in improving neurological recovery and decreasing brain damage in an experimental rat model. In a model of permanent middle cerebral artery occlusion (pMCAO), we analyzed: neurological evaluation; MSCs migration and implantation; interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels; lesion volume; cell death; cellular proliferation; vascular endothelial growth factor (VEGF) expression and blood vessel number. Regardless of the administration route, treated groups showed better neurological recovery, without significant differences between the two groups. Migration and implantation of MSCs in the lesion area was observed in animals receiving i.c. but not i.v. treatment. The highest cytokine values were observed in the i.v. MSCs and i.c. control groups, and these levels were significantly different from the corresponding i.v. control and i.c. MSCs groups, respectively. In addition, there were significant differences between the i.v. MSCs and i.c. MSCs groups in IL-6 levels. Neither treatment reduced infarction volume. However, cell death, measured as TUNEL+ cells was decreased with significant differences between control groups. BrdU+ cells were also significantly increased in the peri-infarct zone at 14 days. VEGF expression was significantly higher in the i.c. MSCs group than in the i.c. control group and blood vessel number was significantly higher in treated groups than control groups with significant differences in the peri-infarct zone at 14 days. We conclude that allogenic MSCs administration shows therapeutic efficacy in our acute ischemic stroke model. Both routes demonstrably improved neurological recovery and provided brain protection.
Since the transmission of pathogenic viruses via water is indistinguishable from the transmission via other routes and since the levels in drinking water, although significant for health, may be too ...low for detection, quantitative viral risk assessment is a useful tool for assessing disease risk due to consumption of drinking water. Quantitative viral risk assessment requires information concerning the ability of viruses detected in drinking water to infect their host. To obtain insight into the infectivity of viruses in relation to the presence of virus genomes, inactivation of three different enteroviruses in artificial ground and surface waters under different controlled pH, temperature, and salt conditions was studied by using both PCR and cell culture over time. In salt-peptone medium, the estimated ratio of RNA genomes to infectious poliovirus 1 in freshly prepared suspensions was about 10⁰. At 4°C this ratio was 10³ after 600 days, and at 22°C it was 10⁴ after 200 days. For poliovirus 1 and 2 the RNA/infectious virus ratio was higher in artificial groundwater than in artificial surface water, but this was not the case for coxsackievirus B4. When molecular detection is used for virus enumeration, it is important that the fraction of infectious virus (based on all virus genomes detected) decays with time, especially at temperatures near 22°C.
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