Evaluating various composite sampling modes for detecting pathogenic SARS-CoV-2 virus in raw sewage.

Inadequate sampling approaches to wastewater analyses can introduce biases, leading to inaccurate results such as false negatives and significant over- or underestimation of average daily viral concentrations, due to the sporadic nature of viral input. To address this challenge, we conducted a field trial within the University of Tennessee residence halls, employing different composite sampling modes that encompassed different time intervals (1 h, 2 h, 4 h, 6 h, and 24 h) across various time windows (morning, afternoon, evening, and late-night). Our primary objective was to identify the optimal approach for generating representative composite samples of SARS-CoV-2 from raw wastewater. Utilizing reverse transcription-quantitative polymerase chain reaction, we quantified the levels of SARS-CoV-2 RNA and pepper mild mottle virus (PMMoV) RNA in raw sewage. Our findings consistently demonstrated that PMMoV RNA, an indicator virus of human fecal contamination in water environment, exhibited higher abundance and lower variability compared to pathogenic SARS-CoV-2 RNA. Significantly, both SARS-CoV-2 and PMMoV RNA exhibited greater variability in 1 h individual composite samples throughout the entire sampling period, contrasting with the stability observed in other time-based composite samples. Through a comprehensive analysis of various composite sampling modes using the Quade Nonparametric ANCOVA test with date, PMMoV concentration and site as covariates, we concluded that employing a composite sampler during a focused 6 h morning window for pathogenic SARS-CoV-2 RNA is a pragmatic and cost-effective strategy for achieving representative composite samples within a single day in wastewater-based epidemiology applications. This method has the potential to significantly enhance the accuracy and reliability of data collected at the community level, thereby contributing to more informed public health decision-making during a pandemic.

Decay of enveloped SARS-CoV-2 and non-enveloped PMMoV RNA in raw sewage from university dormitories.

Introduction: Although severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) RNA has been frequently detected in sewage from many university dormitories to inform public health decisions during the COVID-19 pandemic, a clear understanding of SARS-CoV-2 RNA persistence in site-specific raw sewage is still lacking. To investigate the SARS-CoV-2 RNA persistence, a field trial was conducted in the University of Tennessee dormitories raw sewage, similar to municipal wastewater. Methods: The decay of enveloped SARS-CoV-2 RNA and non-enveloped Pepper mild mottle virus (PMMoV) RNA was investigated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in raw sewage at 4°C and 20°C. Results: Temperature, followed by the concentration level of SARS-CoV-2 RNA, was the most significant factors that influenced the first-order decay rate constants (k) of SARS-CoV-2 RNA. The mean k values of SARS-CoV-2 RNA were 0.094 day-1 at 4°C and 0.261 day-1 at 20°C. At high-, medium-, and low-concentration levels of SARS-CoV-2 RNA, the mean k values were 0.367, 0.169, and 0.091 day-1, respectively. Furthermore, there was a statistical difference between the decay of enveloped SARS-CoV-2 and non-enveloped PMMoV RNA at different temperature conditions. Discussion: The first decay rates for both temperatures were statistically comparable for SARS-CoV-2 RNA, which showed sensitivity to elevated temperatures but not for PMMoV RNA. This study provides evidence for the persistence of viral RNA in site-specific raw sewage at different temperature conditions and concentration levels.

Genotype Diversity of Enteric Viruses in Wastewater Amid the COVID-19 Pandemic.

Viruses remain the leading cause of acute gastroenteritis (AGE) worldwide. Recently, we reported the abundance of AGE viruses in raw sewage water (SW) during the COVID-19 pandemic, when viral AGE patients decreased dramatically in clinics. Since clinical samples were not reflecting the actual state, it remained important to determine the circulating strains in the SW for preparedness against impending outbreaks. Raw SW was collected from a sewage treatment plant in Japan from August 2018 to March 2022, concentrated by polyethylene-glycol-precipitation method, and investigated for major gastroenteritis viruses by RT-PCR. Genotypes and evolutionary relationships were evaluated through sequence-based analyses. Major AGE viruses like rotavirus A (RVA), norovirus (NoV) GI and GII, and astrovirus (AstV) increased sharply (10-20%) in SW during the COVID-19 pandemic, though some AGE viruses like sapovirus (SV), adenovirus (AdV), and enterovirus (EV) decreased slightly (3-10%). The prevalence remained top in the winter. Importantly, several strains, including G1 and G3 of RVA, GI.1 and GII.2 of NoV, GI.1 of SV, MLB1 of AstV, and F41 of AdV, either emerged or increased amid the pandemic, suggesting that the normal phenomenon of genotype changing remained active over this time. This study crucially presents the molecular characteristics of circulating AGE viruses, explaining the importance of SW investigation during the pandemic when a clinical investigation may not produce the complete scenario.

Direct Membrane Filtration of Municipal Wastewater: Studying the Most Suitable Conditions for Minimizing Fouling Rate in Commercial Porous Membranes at Demonstration Scale.

This study aimed to evaluate the feasibility of applying a commercial porous membrane to direct filtration of municipal wastewater. The effects of membrane pore size (MF and UF), treated influent (raw wastewater and the primary settler effluent of a municipal wastewater treatment plant) and operating solids concentration (about 1 and 2.6 g L-1) were evaluated on a demonstration plant. Filtration periods of 2-8 h were achieved when using the MF membrane, while these increased to 34-69 days with the UF membrane. This wide difference was due to severe fouling when operating the MF membrane, which was dramatically reduced by the UF membrane. Use of raw wastewater and higher solids concentration showed a significant benefit in the filtration performance when using the UF module. The physical fouling control strategies tested (air sparging and backwashing) proved to be ineffective in controlling UF membrane fouling, although these strategies had a significant impact on MF membrane fouling, extending the operating period from some hours to 5-6 days. The fouling evaluation showed that a cake layer seemed to be the predominant reversible fouling mechanism during each independent filtration cycle. However, as continuous filtration advanced, a large accumulation of irreversible fouling appeared, which could have been related to intermediate/complete pore blocking in the case of the MF membrane, while it could have been produced by standard pore blocking in the case of the UF membrane. Organic matter represented more than 70% of this irreversible fouling in all the experimental conditions evaluated.

Quantification of infectious Human mastadenovirus in environmental matrices using PMAxx-qPCR.

Molecular methodologies providing data on viral concentration and infectivity have been successfully used in environmental virology, supporting quantitative risk assessment studies. The present study aimed to assess human mastadenovirus (HAdV) intact particles using a derivative of propidium monoazide associated with qPCR (PMAxx-qPCR) in aquatic matrices. Initially, different concentrations of PMAxx were evaluated to establish an optimal protocol for treating different naturally contaminated matrices, using 10 min incubation in the dark at 200 rpm at room temperature and 15 min of photoactivation in the PMA-Lite™ LED photolysis device. There was no significant reduction in the quantification of infectious HAdV with increasing concentration of PMAxx used (20 µM, 50 µM, and 100 µM), except for sewage samples. In this matrix, a reduction of 5.01 log of genomic copies (GC)/L was observed from the concentration of 50 µM and revealed 100% HAdV particles with damaged capsids. On the other hand, the mean reduction of 0.51 log in stool samples using the same concentration mentioned above demonstrated 83% of damaged particles eliminated in the stool. Following, 50 µM PMAxx-qPCR protocol revealed a log reduction of 0.91, 0.67, and 1.05 in other samples of raw sewage, brackish, and seawater where HAdV concentration reached 1.47 × 104, 6.81 × 102, and 2.33 × 102 GC/L, respectively. Fifty micrometers of PMAxx protocol helped screen intact viruses from different matrices, including sea and brackish water.

Human Coronavirus NL63 Among Other Respiratory Viruses in Clinical Specimens of Egyptian Children and Raw Sewage Samples.

The objective of this study was to investigate human coronavirus NL63 (HCoV-NL63) prevalence among the other respiratory viruses such as parainfluenza, respiratory syncytial virus, and non-enteric adenoviruses in clinical specimens of Egyptian children and raw sewage samples. One hundred clinical specimens were collected from Egyptian children suffering from upper and lower respiratory viral infections in the years 2005-2006 to detect HCoV-NL63 genome using RT-PCR. All the specimens were negative for the virus. Also, a complete absence of HCoV-NL63 genome was observed in the twenty-four raw sewage samples collected from two wastewater treatment plants within Greater Cairo from February 2006 to January 2007. Using nested RT-PCR, parainfluenza virus type 1, respiratory syncytial virus type A, adenovirus type 4, and adenovirus type 7 were detected in 3%, 2%, 5%, and 2% of the clinical specimens, respectively. Of these viruses, only adenovirus type 4 was detected in 1/24 (4.17%) of the raw sewage samples, while a complete absence of the other investigated respiratory viruses was observed in the raw sewage samples. The low percentage of positivity in the clinical specimens, the concentration method of the raw sewage samples, and the indirect routes of transmission may be the reasons for the absence of respiratory viruses in raw sewage samples. On the other hand, enteric adenoviruses were detected in 21/24 (87.5%) of the raw sewage samples with a higher prevalence of adenovirus type 41 than adenovirus type 40. A direct route of transmission of enteric viruses to raw sewage may be the reason for the high positivity percentage of enteric adenoviruses in raw sewage samples.

French vertical flow treatment wetlands in a subtropical climate: Characterization of the organic deposit layer and comparison with systems in France.

This paper presents an advanced characterization of the organic fraction of the top deposit layer collected in a French vertical flow treatment wetland (first stage) in operation in Brazil (two units with different organic deposit layer accumulation times), and compares the results with those obtained from studies in France. The organic and inorganic constituents of the samples collected were analysed by biological, chemical and thermochemical methods. The unit with the organic deposit with longer accumulation time (almost 10 years) was characterized as a mature one (organic matter - OM: 51.3 and 52.7%, thermal index - RTGA: 0.79 and 0.85, humification index - HI: 0.61 and 1.16, respectively for the depths of 0-5 cm and 5-10 cm). The unit with the deposit organic with less than three years of accumulation also presented characteristics of a mature deposit (OM: 61.2%, RTGA: 0.79, HI: 1.01 for the depth of 0-5 cm), indicating a rapid mineralization of the deposit under the existing subtropical environment. Despite several differences in term of conception, hydraulic and mass loading rates and accumulation rates, the characteristics of the OM of Brazilian deposits were found to be quite similar to the French ones.

Removal, seasonal variation, and environmental impact of parabens in a municipal wastewater treatment facility in Guangzhou, China.

The occurrence, seasonal variation, and environmental impact of five widely used parabens, methyl-(MeP), ethyl-(EtP), n-propyl-(n-PrP), n-butyl-(n-BuP), and benzyl-(BzP) parabens, were investigated in a municipal wastewater treatment plant (WWTP) located in Guangzhou, China, for 1 year. The concentrations of ∑5parabens in the influent and the effluent were 94.2-957 and 0.89-14.7 ng L-1, respectively. The influent paraben concentrations in autumn were significantly lower than in winter, spring, and summer, and the concentrations were generally higher in spring. The removal efficiencies of ∑5parabens in the dissolved phase were over 96%, with high efficiencies in MeP, EtP, and n-PrP. Risk assessment indicated that parabens in the effluent were not likely to pose an environmental risk to aquatic ecosystems. The present study indicates that the treatment processes employed in full-scale WWTPs are effective at removing parabens and highlights the possibility of utilizing WWTPs for restoring water quality in riverine and coastal regions heavily impacted by paraben contamination.

Evaluation of the environmental and plant growth effectiveness of a new substrate consisting of municipal sludge and fly ash.

In order to seek a safe, sustainable, and low-cost method for reuse of municipal sewage sludge, four species of native plants, i.e., Forsythia suspensa, Sophora japonica, Cotinus coggygria, and Ailanthus altissima were planted in flowerpots containing 4 growth substrates consisting of raw sludge and fly ash at volume/volume ratios of 20:80, 40:60, 60:40, and 80:20, respectively. The results showed that the physiochemical characteristics of the sewage sludge and fly ash were complementary. The sludge supplied the nutrients and the fly ash maintained air permeability in the mixed substrate. The mixed substrates containing 40-60% sewage sludge that belonged to sand clay loam were suitable for the seedling growth of the four species. After the end of the growing season, the electrical conductivity, pH, and contents of organic matter, nitrogen, potassium, and heavy metals in the four growth substrates decreased significantly. Moreover, most of the heavy metals were removed from the substrates by seedling root system. A. altissima grew best, and heavy metal enrichments of F. suspense and C. coggygria were stronger than other two species. The results indicate that the new substrates containing 40-60% sludge exhibiting good physiochemical properties, are environmentally friendly, and suitable for landscape planting.

High prevalence of hepatitis E virus in raw sewage in Southern Italy.

Hepatitis E virus (HEV) infections constitute a significant health problem worldwide. The burden of hepatitis E in Italy seems low when compared with other European countries. In recent years, improved surveillance activities in Italy have revealed marked geographical differences in HEV epidemiology, with some regions characterised by higher seroprevalence rates. Abruzzo Region (Southern Italy) is currently recognised as a high-risk area for HEV infection. In this study, we investigated the epidemiology of HEV in Teramo Province by monitoring four wastewater treatment plants (WWTPs). Out of 56 influent sewage specimens collected during 2016-2017, HEV RNA was detected in 13/56 (23.2%) sewage samples from all the four WWTPs. Upon sequence analysis of the partial ORF2 gene, four strains showed the highest nucleotide identity to Gt3 subtype c, being more closely related to other HEVs previously identified in human and animal hosts in Abruzzo. For one strain, sequence data were generated only for a short region of the ORF1 gene, revealing the highest identity to HEVs Gt3 of subtype f. Altogether, the findings of this study confirm that HEV largely circulates in the setting investigated.

Antibiotic resistance genes are abundant and diverse in raw sewage used for urban agriculture in Africa and associated with urban population density.

A comparative study was conducted to (1) assess the potential of raw sewage used for urban agriculture to disseminate bacterial resistance in two cities of different size in Cameroon (Central Africa) and (2) compare the outcome with data obtained in Burkina Faso (West Africa). In each city, raw sewage samples were sampled from open-air canals in three neighbourhoods. After DNA extraction, the microbial population structure and function, presence of pathogens, antibiotic resistance genes and Enterobacteriaceae plasmids replicons were analysed using whole genome shotgun sequencing and bioinformatics. Forty-three pathogen-specific virulenc e factor genes were detected in the sewage. Eighteen different incompatibility groups of Enterobacteriaceae plasmid replicon types (ColE, A/C, B/O/K/Z, FIA, FIB, FIC, FII, H, I, N, P, Q, R, T, U, W, X, and Y) implicated in the spread of drug-resistance genes were present in the sewage samples. One hundred thirty-six antibiotic resistance genes commonly associated with MDR plasmid carriage were identified in both cities. Enterobacteriaceae plasmid replicons and ARGs found in Burkina Faso wastewaters were also present in Cameroon waters. The abundance of Enterobacteriaceae, plasmid replicons and antibiotic resistance genes was greater in Yaounde, the city with the greater population. In conclusion, the clinically relevant environmental resistome found in raw sewage used for urban agriculture is common in West and Central Africa. The size of the city impacts on the abundance of drug-resistant genes in the raw sewage while ESBL gene abundance is related to the prevalence of Enterobacteriaceae along with plasmid Enterobacteriaceae abundance associated to faecal pollution.

Surveillance of Giardia and Cryptosporidium in sewage from an urban area in Brazil / Monitoramento de Giardia e Cryptosporidium em esgoto de uma área urbana no Brasil

Abstract Cryptosporidium and Giardia are protozoan parasites that cause diarrhea in humans and animals. Molecular characterization of these pathogens in sewage may provide insight on their occurrence and prevalence in Brazil. This study aimed to investigate the presence of Giardia and Cryptosporidium in raw and treated sewage from Londrina, Paraná, Brazil. Samples were collected every two weeks during a year. Samples were concentrated, then DNA was extracted and subjected to a nested PCR targeting the Giardia 18S rRNA gene and the Cryptosporidium 18S rRNA gene. Species of Cryptosporidium were characterized by restriction fragment length polymorphism (RFLP). All raw sewage and 76% of the treated sewage were positive for Giardia; 84% of raw sewage samples and 8% of treated sewage were positive for Cryptosporidium. C. muris, C. hominis, C. baileyi, C. parvum and C. suis were detected in 100%, 19%, 9%, 9% and 4% of raw sewage, respectively. C. muris was the only species found in treated sewage. Multiple species of Cryptosporidium were present in 19.04% of the raw sewage. Treated sewage water can pose a threat to human health. The speciation of Cryptosporidium revealed the presence of non-common zoonotic species as C. suis and C. muris.

Resumo Cryptosporidium e Giardia são protozoários causadores de diarreia em animais e humanos. A caracterização molecular destes protozoários em esgoto pode prover dados ainda desconhecidos da ocorrência de espécies. O objetivo do presente estudo foi monitorar a ocorrência de Giardia e espécies de Cryptosporidium em esgoto bruto e tratado em uma estação de tratamento de esgoto (ETE) de Londrina, Paraná. Amostras de esgoto bruto e tratado foram coletadas no período de um ano, com periodicidade quinzenal. A ocorrência destes protozoários foi caracterizada por meio de concentração das amostras e posterior extração de DNA seguida de nested-PCR para amplificação de fragmentos dos genes 18S rRNA de Giardia e 18S rRNA de Cryptosporidium. A caracterização das espécies de Cryptosporidium foi realizada por meio de análise por polimorfismo de comprimento do fragmento de restrição (RFLP) dos produtos obtidos. Foram coletadas no total 25 amostras de cada, esgoto bruto e esgoto tratado. Para Giardia, todas as amostras de esgoto bruto e 76% das de esgoto tratado foram positivas. Cryptosporidium esteve presente em 84% das amostras de esgoto bruto e em 8% do tratado. No esgoto tratado foi encontrado apenas C. muris, já nas amostras de esgoto bruto foram encontradas cinco espécies: C. muris, C. hominis, C. baileyi, C. suis e C. parvum em 100%, 19%, 9%, 9% e 4%, respectivamente. A presença de espécies mistas foi observada em 19,04% das amostras. A presença de Giardia e Cryptosporidium em esgoto tratado pode pôr em risco a saúde humana. A discriminação de espécies de Cryptosporidium revelou a presença de espécies zoonóticas incomuns como C. suis e C. muris.

Ocorrência de fármacos e desreguladores endócrinos em esgoto bruto e tratado na cidade de Belo Horizonte (MG) / Occurrence of drugs and endocrine disrupters in raw and treatment sewage in the city of Belo Horizonte / MG, Brazil

RESUMO Os compostos de preocupação emergente (contaminants of emerging concern - CECs) atingem constantemente os corpos d'água via lançamento de esgoto sanitário, efluentes industriais e lixiviados de aterro, disposição inadequada de resíduos sólidos e escoamento superficial, ocasionando a poluição dos cursos d'água. Geralmente estes se encontram em concentrações da ordem de nanograma por litro ou micrograma por litro, dificultando sua análise ou onerando esse processo, demandando, assim, o desenvolvimento de técnicas de preparo e extração. Nesse contexto, destaca-se a Partição a Baixa Temperatura (EPBT), que se baseia na partição do analito de interesse entre fase aquosa e fase orgânica. Face ao exposto e à relevância do tema, o presente trabalho teve como objetivo avaliar, pelo uso da EPBT e cromatografia gasosa acoplada à espectrometria de massas, a ocorrência de 16 CECs no esgoto bruto e no tratado de Belo Horizonte (MG).

ABSTRACT Contaminants of Emerging Concern (CECs) constantly reach water bodies through the discharge of sanitary sewage, industrial effluents and landfill leachate, inadequate disposal of solid waste and surface runoff, causing the pollution of watercourses. In general, these are in concentrations of the order of mg / L or ng / L, making it difficult to analyze or burden this process, thus requiring the development of preparation and extraction techniques. In this context, it stands out the Low Temperature Patitioning Extraction (LTPE), which is based on the partition of the analyte of interest between aqueous phase and organic phase. Bearing this and the relevance of the subject in mind, the present work had the objective of evaluating the occurrence of 16 CECs in the crude and treated sewage of Belo Horizonte / MG, by using LTPE and gas chromatography coupled to mass spectrometry.

Detection of nineteen enteric viruses in raw sewage in Japan.

One-year surveillance for enteric viruses in raw sewage was conducted in Kansai area, central part of Japan from July 2015 to June 2016. The raw sewage was collected monthly from an inlet polluted pool and was concentrated by polyethylene glycol (PEG) precipitation. Twelve sewage samples were screened for nineteen kinds of enteric viruses by using RT-PCR method and further analyzed by nucleotide sequencing. Twelve enteric viruses were found in the investigative sewage samples. Rotavirus A and norovirus GI and GII with several genotypes were detected all year round. Interestingly, norovirus GII.17 (Kawasaki-like strain) and rotavirus G2 that caused the outbreaks in Japan last epidemic season were also found in sewage. Moreover, adenovirus, astrovirus, sapovirus, bocavirus, human parechovirus, enterovirus, Aichi virus, Saffold virus and salivirus were also detected. Enterovirus D68 was detected only in the same month as those of enterovirus D68 outbreak in Japan. The rotavirus B and C, hepatitis A and E viruses, human cosavirus, bufavirus and rosavirus were not detected in this surveillance. The study provides the information on the enteric viruses contaminated in raw sewage, which is valuable for risk assessment. Our results imply that the viruses detected in sewage may be associated with infections in the Japanese population.

Wastewater pollution differently affects the antibiotic resistance gene pool and biofilm bacterial communities across streambed compartments.

Wastewater discharges introduce antibiotic residues and antibiotic-resistant bacteria (ARB) into surface waters. Both inputs directly affect the streambed resistome, either by exerting a selective pressure that favour the proliferation of resistant phenotypes or by enriching the resident communities with wastewater-associated ARB. Here, we investigated the impact of raw and treated urban wastewater discharges on epilithic (growing on rocks) and epipsammic (growing on sandy substrata) streambed biofilms. The effects were assessed by comparing control and impact sites (i) on the composition of bacterial communities; (ii) on the abundance of twelve antibiotic resistance genes (ARGs) encoding resistance to ß-lactams, fluoroquinolones, sulphonamides, tetracyclines, macrolides and vancomycin, as well as the class 1 integron-integrase gene (intI1); (iii) on the occurrence of wastewater-associated bacteria, including putative pathogens, and their potential linkage to target ARGs. We measured more pronounced effects of raw sewage than treated wastewater at the three studied levels. This effect was especially noticeable in epilithic biofilms, which showed a higher contribution of wastewater-associated bacteria and ARB than in epipsammic biofilms. Comparison of correlation coefficients obtained between the relative abundance of both target ARGs and operational taxonomic units classified as either potential pathogens or nonpathogens yielded significant higher correlations between the former category and genes intI1, sul1, sul2 and ermB. Altogether, these results indicate that wastewater-associated micro-organisms, including potential pathogens, contribute to maintain the streambed resistome and that epilithic biofilms appear as sensitive biosensors of the effect of wastewater pollution in surface waters.

Identification of new bacteria harboring qnrS and aac(6')-Ib/cr and mutations possibly involved in fluoroquinolone resistance in raw sewage and activated sludge samples from a full-scale WWTP.

Wastewater treatment plants (WWTPs) harbor bacteria and antimicrobial resistance genes, favoring gene exchange events and resistance dissemination. Here, a culture-based and metagenomic survey of qnrA, qnrB, qnrS, and aac(6')-Ib genes from raw sewage (RS) and activated sludge (AS) of a full-scale municipal WWTP was performed. A total of 96 bacterial isolates were recovered from nalidixic acid-enrichment cultures. Bacteria harboring the aac(6')-Ib gene predominated in RS, whereas qnrS-positive isolates were specific to AS. Novel qnrS- and aac(6')-Ib-cr positive species were identified: Morganella morganii, Providencia rettgeri, and Pseudomonas guangdongensis (qnrS), and Alcaligenes faecalis and P. rettgeri (aac(6')-Ib-cr). Analysis of qnrS and aac(6')-Ib sequences from isolates and clone libraries suggested that the diversity of qnrS is wider than that of aac(6')-Ib. A large number of amino acid mutations were observed in the QnrS and AAC(6')-Ib proteins at previously undetected positions, whose structural implications are not clear. An accumulation of mutations at the C72, Q73, L74, A75 and M76 positions of QnrS, and D181 of AAC(6')-Ib might be important for resistance. These findings add significant information on bacteria harboring qnrS and aac(6')-Ib genes, and the presence of novel mutations that may eventually emerge in clinical isolates.

Raw sewage as breeding site to Aedes (Stegomyia) aegypti (Diptera, culicidae).

The selection of oviposition sites by females of Aedes (Stegomyia) aegypti is a key factor for the larval survival and egg dispersion and has a direct influence in vector control programs. In this study, we evaluated the aspects of reproductive physiology of Ae. aegypti mosquitoes tested in the presence of raw sewage. Ae. aegypti females were used in oviposition bioassays according to two methodologies: (i) choice assay, in which three oviposition substrates were offered in the same cage: treatment (raw sewage), positive control (distilled water) and negative control (1% sodium hypochlorite) and; (ii) no choice assay, in which only one substrate was available. The physicochemical and microbiological analysis of the raw sewage used in this study indicated virtually no levels of chlorine, low levels of dissolved oxygen and high levels of nitrogenous compounds as well as the presence of Escherichia coli and total fecal coliforms. After 72h of oviposition, the eggs were counted and there was no statistically significant difference (p>0.05) in the oviposition rate between raw sewage and positive control in both methodologies. In addition, females were dissected to evaluate egg-retention and also there were no appreciable differences in egg retention even when raw sewage was the only substrate offered. The data also showed that egg hatching and larvae development occurred normally in the raw sewage. Therefore, the present study suggests that Ae. aegypti can adapt to new sites and lay eggs in polluted water, such as the raw sewage. These findings are of particular importance for the control and surveillance programs against Ae. aegypti in countries where the conditions of poor infrastructure and lack of basic sanitation are still an issue.

A preliminary nationwide survey of the presence of emerging contaminants in drinking and source waters in Brazil.

This is the first nationwide survey of emerging contaminants in Brazilian waters. One hundred drinking water samples were investigated in 22 Brazilian state capitals. In addition, seven source water samples from two of the most populous regions of the country were evaluated. Samples were collected from June to September of 2011 and again during the same period in 2012. The study covered emerging contaminants of different classes, including hormones, plasticizers, herbicides, triclosan and caffeine. The analytical method for the determination of the compounds was based on solid-phase extraction followed by analysis via liquid chromatography electrospray triple-quadrupole mass spectrometry (LC-MS/MS). Caffeine, triclosan, atrazine, phenolphthalein and bisphenol A were found in at least one of the samples collected in the two sampling campaigns. Caffeine and atrazine were the most frequently detected substances in both drinking and source water. Caffeine concentrations in drinking water ranged from 1.8ngL-1 to values above 2.0µgL-1 while source-water concentrations varied from 40ngL-1 to about 19µgL-1. For atrazine, concentrations were found in the range from 2.0 to 6.0ngL-1 in drinking water and at concentrations of up to 15ngL-1 in source water. The widespread presence of caffeine in samples of treated water is an indication of the presence of domestic sewage in the source water, considering that caffeine is a compound of anthropogenic origin.

[Community Structure and Activity Analysis of the Nitrifiers in Raw Sewage of Wastewater Treatment Plants].

The communities and activity of nitrifiers collected from the raw sewage of the 2nd and 3rd wastewater treatment plants (WWTP) in Xi'an were investigated. FISH results indicated that the (AOB+NOB)/EUB percentages were (5.35±2.1)% and(6.0±2.8)% in the 2nd and 3rd WWTP, respectively. The dominant AOB was Nitrosomonas europaea/Nitrosococcus mobilis lineage and the dominant NOB was Nitrospira, the sub-dominant NOB was Nitrobacter, and coexisted with Nitrococcus, Nitrospina. Respirometric assays showed that the influent nitrifiers were active following a 2-16 hour period of metabolic induction. The ammonium utilized rate was (0.32±0.12) mg·(L·h)-1 and (0.43±0.17) mg·(L·h)-1, nitrite utilized rate was (0.71±0.18) mg·(L·h)-1 and (0.58±0.27) mg·(L·h)-1 for nitrifers in raw sewage fed to the 2nd and 3rd WWTP, respectively. Therefore, nitrifiers were present and active in the raw sewage, and played the role of natural continuous seeding in the activated sludge system. Based on the nitrification activity, the estimated continuous seeding intensity of AOB and NOB was 0.08-0.09 g·(g·d)-1 and 0.11-0.24 g·(g·d)-1, respectively.