Microbial diversity characterizations, associated pathogenesis and antimicrobial resistance profiling of Najafgarh drain.

The Najafgarh drain plays a significant role in the pollution of the Yamuna River, accounting for 40% of the total pollution. Therefore, it is crucial to investigate and analyze the microbial diversity, metabolic functional capacity, and antibiotic resistance genes (ARGs) present in the Najafgarh drain. Additionally, studying the water quality and its relationship with the proliferation of microorganisms in the drain is of utmost importance. Results obtained confirmed the deteriorated water quality as physico-chemical parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), and total suspended solids (TSS) in the range of 125-140, 400-460, 0-0.2, 25-140.4 mg/l respectively violated the standard permissible national and global standards. In addition, the next generation sequencing (NGS) analysis confirm the presence of genus such as Thauera, Arcobacter, Pseudomonas, Geobacter, Dechloromonas, Tolumonas, Sulfurospirullum, Desulfovibrio, Aeromonas, Bacteroides, Prevotella, Cloacibacterium, Bifidobacterium, Clostridium etc. along with 864 ARGs in the wastewater obtained from the Najafgarh drain. Findings confirm that the pathogenic species reported from this dataset possess severe detrimental impact on faunal and human health. Further, Pearson's r correlation analysis indicated that environmental variables, mainly total dissolved solids (TDS) and chemical oxygen demand (COD), play a pivotal role in driving microbial community structure of this heavily polluted drain. Thus, the poor water quality, presence of a microbial nexus, pathogenic markers, and ARGs throughout this drain confirmed that it would be one potential contributor to the dissemination of disease-causing agents (pathogens) to the household and drinking water supplies in the near future.

Diving into the unknown: identification of antimicrobial resistance hotspots in a tropical urban estuary.

Antimicrobial resistance is widely studied and well-characterized from a clinical perspective. However, considerably less information is available regarding resistance in environmental settings, especially in aquatic habitats. This study presents data regarding the occurrence, distribution and the antimicrobial susceptibility profile of bacteria isolated from Guanabara Bay (GB), a heavily polluted tropical urban estuary and an important tourist attraction in Rio de Janeiro, Brazil. Water samples from sites characterized by growing degrees of pollution were analysed by culture-dependent methods, revealing the presence of multidrug-resistant bacteria and clinically relevant indicators of antimicrobial resistance, such as extended-spectrum beta-lactamases. Isolates were identified by mass spectrometry, which indicated the presence of potential human pathogens such as Aeromonas spp. and Vibrio spp. Bacteria harbouring beta-lactam resistance genes were also detected. Although GB is widely used as a recreational and fishing area, there is a substantial knowledge gap regarding the monitoring of antimicrobial resistance and the risk that exposure to these waters poses to public health. Thus, this study reveals new information that calls for better comprehension of antimicrobial resistance in aquatic environments, especially those used for recreational purposes.

Battling a Common Enemy: Joining Forces in the Fight against Sewage Pollution.

The health of both coral reefs and people are imperiled by a local threat that is widespread across the globe-sewage and the typical components it carries (e.g., nutrients, sediments, heavy metals, endocrine disruptors, pathogens, and pharmaceuticals). Despite this common threat, those concerned with human health and those concerned with coral reef health have rarely joined forces. To jump-start an alliance between coral conservation and human health sectors, this article documents the threats that humans and reefs face and identifies threat-abatement strategies that will benefit both people and reefs, highlighting the mitigation of water pollution as a prime example. By joining forces, marine conservationists and human health practitioners can increase the amount and efficiency of both intellectual and financial resources they bring to bear against sewage.

Object-based image analysis for the impact of sewage pollution in Malad Creek, Mumbai, India.

Today, object-based image analysis provides an option for integrating spatial information beyond conventional pixel-based classifications for high-resolution imagery. Due to its rare applicability in pollution assessment, an attempt has been made to assess the spatial extent of sewage pollution in Malad Creek, Mumbai, India. Based on multiresolution segmentation of an IRS P6 (LISS IV) image and the Normalized Difference Turbidity Index (NDTI), the various water quality regions in the creek were classified. The existing literature implies that the reflectance of turbid water is similar to that of bare soil which gives positive NDTI values. In contrast to this, negative values of NDTI are observed in the present study due to the presence of organic matter which absorbs light and imparts turbidity, which is supported by the significant correlation between NDTI and turbidity. A strong relationship is observed between turbidity and water quality parameters, implying the impact of organic matter through discharges of sewage in the creek. Based on the classified regions and the water quality parameters, the extent of pollution was ranked as high, moderate, low and least. The methodology developed in the present study was successfully applied on an IKONOS image for the same study area but a different time frame. The approach will help in impact assessment of sewage pollution and its spatial extent in other water bodies.

Relative inactivation of faecal indicator bacteria and sewage markers in freshwater and seawater microcosms.

UNLABELLED: In this study, the relative inactivation of faecal indicator bacteria (FIB) namely Escherichia coli, enterococci and sewage markers [Bacteroides HF183 and human adenoviruses (HAVs)] was assessed in sewage-spiked freshwater and seawater microcosms under ambient subtropical climatic conditions. The numbers of declining FIB were measured with culture-based methods, whereas the numbers of sewage markers were measured with qPCR assays. The T90 inactivation times of E. coli, enterococci and the HF183 markers in both freshwater and seawater microcosms were <3·5 days, suggesting the suitability of the HF183 marker to identify recent sewage pollution events. The T90 value of HAVs (9·4-13 days), however, was significantly higher than FIB and the HF183 marker in both freshwater (P < 0·001) and seawater (P < 0·05) microcosms. Therefore, we recommend that HAVs should be used as an additional marker to adequately assess the potential health risks associated with longer-term sewage-polluted environmental waters. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we have shown that the persistence of the Bacteroides HF183 marker in freshwater and seawater microcosms was similar to faecal indicator bacteria (Escherichia coli and enterococci), whereas human adenoviruses (HAVs) persisted relatively longer. These findings suggest the suitability of both the markers to identify sewage pollution in environmental waters. However, HF183 marker appeared to be more useful than HAVs in identifying recent sewage pollution. As, HAVs may remain infective for lengthy periods, it should be used in conjunction with the HF183 marker to obtain information on the potential human health risks associated with sewage-polluted freshwater and seawater.

Detection and source tracking of Escherichia coli, harboring intimin and Shiga toxin genes, isolated from the Little Bighorn River, Montana.

The Little Bighorn River flows through the Crow Indian Reservation in Montana. In 2008, Escherichia coli concentrations as high as 7179 MPN/100 ml were detected in the river at the Crow Agency Water Treatment Plant intake site. During 2008, 2009, and 2012, 10 different serotypes of E. coli, including O157:H7, harboring both intimin and Shiga toxin genes were isolated from a popular swim site of the Little Bighorn River in Crow Agency. As part of a microbial source tracking study, E. coli strains were isolated from river samples as well as from manure collected from a large cattle feeding operation in the upper Little Bighorn River watershed; 23% of 167 isolates of E. coli obtained from the manure tested positive for the intimin gene. Among these manure isolates, 19 were identified as O156:H8, matching the serotype of an isolate collected from a river sampling site close to the cattle feeding area.

Anthropogenic nitrogen pollution inferred by stable isotope records of crustose coralline algae.

Since reef ecosystems can offer intricate habitats for various marine organisms, calcified reefs may contain valuable long-term environmental data. This study investigated stable isotopic composition of marine organisms from the Taoyuan and Linshanbi crustose coralline algae (CCA) reef ecosystems to understand sewage pollution. CCA samples from Taoyuan (Palaeo Xin A: ∼1000 years old and Palaeo G: ∼7000 years old) and Linshanbi (Palaeo L: ∼7000 years old and modern CCA) had significantly lower δ15N values (2.5-5.6 ‰) compared to modern CCA from Taoyuan (10.2 ± 1.2 ‰). Intertidal organisms from the Taoyuan CCA reef also showed higher δ15N values than those from Linshanbi CCA reef, indicating anthropogenic stress in both ecosystems. Long-term pollution monitoring and effective strategies to mitigate sewage pollution are recommended for these CCA reef ecosystems.

Microbial source tracking of fecal pollution to coral reef lagoons of Norfolk Island, Australia.

Fecal pollution contributes to global degradation of water quality and requires identification of the source(s) for predicting human health risk, tracking disease, and developing management strategies. While fecal indicator bacteria are commonly used to detect fecal pollution, they cannot identify sources. Novel approaches, such as microbial source tracking (MST), can be applied to evaluate the origin of fecal pollution. This study examined fecal pollution in the coral reef lagoons of Norfolk Island, Australia where reef health decline has been related to nutrient input. The primary objective of this study was to evaluate the host sensitivity and specificity of two human wastewater-associated marker genes (Bacteroides HF183 (HF183) and cross-assembly phage (crAssphage)) and four animal feces associated marker genes targeting avian, ruminant, dog, and pig (Helicobacter-associated GFD (GFD), Bacteroides BacR (BacR), Bacteroides DogBact (DogBact), and Bacteroides Pig-2-Bac (Pig-2-Bac)) in wastewater and animal fecal samples collected from Norfolk Island. The prevalence and concentrations of these marker genes along with enterococci genetic marker (ENT 23S rRNA) of general fecal pollution and human adenovirus (HAdV), which is considered predominantly a pathogen but also a human-wastewater associated marker gene, were determined in surface, ground, and marine water resources. A secondary objective of this study was to assess the sources and pathways of fecal pollution to a sensitive marine environment under rainfall events. HF183, crAssphage, HAdV, and BacR demonstrated absolute host sensitivity values of 1.00, while GFD and Pig-2-Bac had host sensitivity values of 0.60, and 0.20, respectively. Host specificity values were > 0.94 for all marker genes. Human and animal (avian, ruminant, dog) fecal sources were present in the coral reef lagoons and surface water whereas groundwater was polluted by human wastewater markers. This study provides understanding of fecal pollution in water resources on Norfolk Island, Australia after precipitation events. The results may aid in effective water quality management, mitigating potential adverse effects on both human and environmental health.

Human health risk attributed to consumption of seafood and recreation swimming in Negombo Lagoon, Sri Lanka: An assessment on lagoon water and inhabitant oysters (Crassostrea cucullata Born, 1778).

The Negombo Lagoon is a coastal lagoon influenced by local communities that introduce waste into its ecosystem. This study examined seven sewage entry points, out of which five sites were chosen for oyster sampling based on availability. Physicochemical and microbiological parameters of water (measured in triplicate at each site, n = 84) and oyster samples (total length, TL > 6 cm, n = 30) were assessed. Variation in regional coliform contamination was analyzed employing a one-way analysis of variance (ANOVA). Results indicated that the northern part of the lagoon exceeded recommended coliform thresholds for swimming (total coliform concentration (TCC) < 126 most probable number (MPN)) and seafood consumption (TCC < 100 MPN/g), indicating the presence of Escherichia coli. Water quality indices affirmed fecal pollution, except in the southern part of the lagoon. Furthermore, the study found high oyster consumption (76.7 %), elucidating that oysters from the northern part of Negombo Lagoon pose health risks.

Reduction of human fecal markers and enteric viruses in Sydney estuarine waters receiving wet weather overflows.

The current microbial source tracking (MST) study tracked the reduction of the culturable fecal indicator bacteria enterococci, four human fecal markers (Bacteroides HF183, Lachnospiraceae Lachno3, cross-assembly phage (CrAssphage) and pepper mild mottle virus (PMMoV)) along with four enteric viruses - human adenovirus 40/41 (HAdV 40/41), enterovirus (EV), human norovirus GI (HNoV GI) and GII (HNoV GII) post wet weather overflows (WWOs) at two estuarine water sites from two depths under separate six-day sampling campaigns over seven and 12 days in Sydney, NSW, Australia. Neither HNoV GI nor GII was detected, while 13.9 % (10/72) of estuarine water samples had detections of EV. Quantifiable concentrations (0.64 to 2.00 log10 gene copies (GC)/100 mL) for HAdV 40/41 were returned from 65.2 % (47/72) of samples collected across the two sites and two depths with 30 quantifications recorded in the surface layer samples. In contrast the presence of HF183, Lachno3, CrAssphage, and PMMoV markers was observed in all 36 (100 %) estuarine water samples collected from the surface layer from both sites. Detection frequencies of these markers were slightly lower at 1 m above the bottom surface. The concentrations of the human fecal markers were compared to established gastrointestinal (GI) risk benchmarks. The concentrations of HF183, Lachno3 and CrAssphage marker only exceeded the GI risk benchmark until day 3, while concentrations of PMMoV marker were indicative of exceedance of the GI risk benchmark on day 7 post WWOs that was much longer than indicated by culturable enterococci concentrations that were within this GI risk benchmark by day 2 and day 4 for the two sites, respectively.

Submarine outfall effect on subtidal macrobenthic communities in a southwestern Atlantic coastal city.

Submarine outfalls are an effective alternative for the final discharge of wastewater. The aim was to evaluate the subtidal macrobenthic community's responses and the changes in bottom sedimentary dynamics due to submarine outfall (SO) location. Sampling stages were: before SO (BSO), after SO (ASO) and after treatment plant (AEDAR). Sampling sites were determined at different distances from the coastline (coastal, oceanic, and reference) on both sides of the pipe (North and South). Species shifts (from tolerant to sensitive) were observed along with a decrease in organic matter in the AEDAR Stage. There were changes in the sedimentary dynamic with sediment accumulation on the South side of the SO (finest sediments) and erosion on the North side (coarsest sediments) in the ASO and AEDAR Stages. Species turnover was higher than nesting in all stages. Functional trait analysis allowed the identification of temporal variations in benthic communities. The body size, development mode, feeding mode, habit, adult mobility and tolerance to pollution were useful functional traits to detect changes through Stages (BSO, ASO, and AEDAR). Biotic indices classified the sites as slightly disturbed, indicating a slight improvement in the AEDAR Stage.

Microbial source tracking of untreated human wastewater and animal scats in urbanized estuarine waters.

The study assessed the performance characteristics of host sensitivity, host specificity and concentration for seven human wastewater- and six animal scat-associated marker genes by analysing human wastewater and animal scat samples from urban catchments of the mega-coastal city of Sydney, Australia. Absolute host sensitivity was exhibited across three criteria used to assess seven human wastewater-associated marker genes of cross-assembly phage (CrAssphage), human adenovirus (HAdV), Bacteroides HF183 (HF183), human polyomavirus (HPyV), Lachnospiraceae (Lachno3), Methnobrevibacter smithii nifH (nifH) and pepper mild mottle virus (PMMoV). In contrast, only the horse scat-associated marker gene Bacteroides HoF597 (HoF597) exhibited absolute host sensitivity. The absolute host specificity value of 1.0 was returned for the wastewater-associated marker genes of HAdV, HPyV, nifH and PMMoV for each of the three applied host specificity calculation criteria, while values of >0.9 were returned for CrAssphage and Lachno3. Ruminants and cow scat-associated marker genes of BacR and CowM2, respectively exhibited the absolute host specificity value of 1.0. Concentrations of Lachno3 were greater in most human wastewater samples followed by CrAssphage, HF183, nifH, HPyV, PMMoV and HAdV. Human wastewater marker genes were detected in several scat samples from cats and dogs, and this suggests concordant sampling of animal scat-associated marker genes and at least two human wastewater-associated marker genes will be required to assist in interpretation of fecal sources in environmental waters. A greater prevalence, together with several samples with greater concentrations of human wastewater-associated marker genes PMMoV and CrAssphage warrant consideration by water quality managers for the detection of diluted human fecal pollution in estuarine waters.

Microbiologically Induced Concrete Corrosion: A Concise Review of Assessment Methods, Effects, and Corrosion-Resistant Coating Materials.

Microbiologically induced concrete corrosion (in wastewater pipes) occurs mainly because of the diffusion of aggressive solutions and in situ production of sulfuric acid by microorganisms. The prevention of concrete biocorrosion usually requires modification of the mix design or the application of corrosion-resistant coatings, which requires a fundamental understanding of the corrosion process. In this regard, a state-of-the-art review on the subject is presented in this paper, which firstly details the mechanism of microbial deterioration, followed by assessment methods to characterize biocorrosion and its effects on concrete properties. Different types of corrosion-resistant coatings are also reviewed to prevent biocorrosion in concrete sewer and waste-water pipes. At the end, concluding remarks, research gaps, and future needs are discussed, which will help to overcome the challenges and possible environmental risks associated with biocorrosion.

Tracking the historical urban and rural sources of fecal pollution in a South American tropical semi-arid region using sterols and endocrine-disrupting chemicals.

Sterols and endocrine-disrupting chemicals were analyzed in two dated sediment cores collected in the Jaguaribe river to determine the recent decades' influence of urbanization and agropastoral activities on the inputs of fecal pollution in a semi-arid region of Brazil. Stigmasterol and sitosterol were the most abundant of the 6 sterols examined in both cores, indicating an important contribution of organic matter from mangrove forests to the study region. Coprostanol presented a continuous increase in concentrations from the 1930s to the 2000s in one core, however, showing higher concentrations (>100 ng g-1) in the upper layers of both cores. The sterols diagnostic ratios indicated fecal pollution through both cores, especially from the 1940s to 1970s. The coprostanol levels followed the variations in population growth in the state of Ceará. Estriol and estrone were the most abundant estrogenic hormones found in both cores. These compounds are probably related to the intense livestock activities in the Ceará state, especially after the 1970s. The baseline levels of fecal sterols and estrogen hormones found in this study possibly represent a previous unimpacted scenario and may be used for future evaluations of fecal pollution from urbanization and livestock activities.

Antibiotic Resistance and Sewage-Associated Marker Genes in Untreated Sewage and a River Characterized During Baseflow and Stormflow.

Since sewage is a hotspot for antibiotic resistance genes (ARGs), the identification of ARGs in environmental waters impacted by sewage, and their correlation to fecal indicators, is necessary to implement management strategies. In this study, sewage treatment plant (STP) influent samples were collected and analyzed using quantitative polymerase chain reaction (qPCR) to investigate the abundance and correlations between sewage-associated markers (i.e., Bacteroides HF183, Lachnospiraceae Lachno3, crAssphage) and ARGs indicating resistance to nine antibiotics (belonging to aminoglycosides, beta-lactams, sulfonamides, macrolides, and tetracyclines). All ARGs, except bla VIM, and sewage-associated marker genes were always detected in untreated sewage, and ermF and sul1 were detected in the greatest abundances. intl1 was also highly abundant in untreated sewage samples. Significant correlations were identified between sewage-associated marker genes, ARGs and the intl1 in untreated sewage (τ = 0.488, p = 0.0125). Of the three sewage-associated marker genes, the BIO-ENV procedure identified that HF183 alone best maximized correlations to ARGs and intl1 (τ = 0.590). Additionally, grab samples were collected from peri-urban and urban sites along the Brisbane River system during base and stormflow conditions, and analyzed for Escherichia coli, ARGs, the intl1, and sewage-associated marker genes using quantitative polymerase chain reaction (qPCR). Significant correlations were identified between E. coli, ARGs, and intl1 (τ = 0.0893, p = 0.0032), as well as with sewage-associated marker genes in water samples from the Brisbane River system (τ = 0.3229, p = 0.0001). Of the sewage-associated marker genes and E. coli, the BIO-ENV procedure identified that crAssphage alone maximized correlations with ARGs and intl1 in river samples (τ = 0.4148). Significant differences in E. coli, ARGs, intl1, and sewage-associated marker genes, and by flow condition (i.e., base vs. storm), and site types (peri-urban vs. urban) combined were identified (R = 0.3668, p = 0.0001), where percent dissimilarities between the multi-factorial groups ranged between 20.8 and 11.2%. Results from this study suggest increased levels of certain ARGs and sewage-associated marker genes in stormflow river water samples compared to base flow conditions. E. coli, HF183 and crAssphage may serve as potential indicators of sewage-derived ARGs under stormflow conditions, and this merits further investigation. Data presented in this study will be valuable to water quality managers to understand the links between sewage pollution and ARGs in urban environments.

Long-Term Interannual and Seasonal Links between the Nutrient Regime, Sestonic Chlorophyll and Dominant Bluegreen Algae under the Varying Intensity of Monsoon Precipitation in a Drinking Water Reservoir.

Long-term variations in reservoir water chemistry could provide essential data in making sustainable water quality management decisions. Here, we analyzed the spatiotemporal variabilities of nutrients, sestonic chlorophyll-a (CHL-a), nutrient enrichment, dominant algal species, and overall chemical water health of the third-largest drinking water reservoir in South Korea during 2000-2020. Our results distinctly explained the strong influence of monsoon rainfall on spatial and annual water chemistry variations. We observed a consistent increase in the chemical oxygen demand alluding to organic matter pollutants, while a steady declining trend in the sestonic CHL-a. The long-term total phosphorus (TP) level showed a steady reduction from the riverine zone to the lacustrine area. However, a higher total coliform bacteria (TCB) was observed at the water intake tower sites. TP displayed a strong link to algal CHL-a and ambient nitrogen phosphorus ratios, suggesting a robust phosphorus-limitation state. The severe phosphorus-limitation was also corroborated by the findings of trophic state index deviation. The high and low flow dynamics exhibited the strong influence of intensive rainfall carrying many nutrients and sediments and flushing out the sestonic CHL-a. Successive eutrophic conditions prevailed along with dominating blue-green algae species (Microcystis and Anabaena). We observed a strong positive correlation (r = 0.62) between water temperature and CHL-a and between total suspended solids and TP (r = 0.65). The multi-metric water pollution index characterized the overall water quality as 'good' at all the study sites. In conclusion, the long-term spatiotemporal variabilities of the ecological functions based on the nutrient-CHL-a empirical models are regulated mainly by the intensive monsoon precipitation. The drinking water could become hazardous under the recurrent eutrophication events and chemical degradations due to uncontrolled and untreated inflow of sewage and wastewater treatment plant effluents. Therefore, we strongly advocate stringent criteria to mitigate phosphorus and organic pollutant influx for sustainable management of Daecheong Reservoir.

Occurrence and fate of linear alkylbenzenes and their potential as environmental molecular markers in highly urbanized river systems.

Rapid industrialization, urbanization, and population growth have led to the common occurrence of black-stinking urban rivers. Assessing regional anthropogenic influences is beneficial to develop effective remediation strategies. This study comprehensively investigated the occurrence and fate of linear alkylbenzenes (LABs) as molecular markers of anthropogenic influences in three media (filtered water, suspended particulate matter (SPM), and sediment) in a highly urbanized river (Baihaimian River) in Guangzhou, South China. The concentrations of LABs ranged from 41 to 215 ng/L in the dissolved phase, from 7122 to 46,640 ng/g dry weight in the SPM phase, and from 73 to 3650 ng/g dry weight in surface sediments (0-10 cm depth). The spatial distribution of LABs was probably affected by the surrounding environment, river flux, and sediment properties. No biotransformation of LABs in water samples and a slight biotransformation in sediments were observed. Significant correlations were found between total nitrogen, ammonia nitrogen, and LABs in river water, indicating the same domestic wastewater sources. The positive correlation between total organic carbon (TOC) and LABs in sediments suggested that TOC worked as the controlling factor for the redistribution of LABs and that local sewage discharge was the dominant TOC input. The total mass inventory of LABs in sediment in Baihaimian River was 21 kg. The total mass of LABs released into Baihaimian River was 183 kg per year, among them, 63% was discharged into the adjacent Liuxi River.

[Distribution and Influencing Factors of DOM Components in Urban and Suburban Polluted Rivers].

Dissolved organic matter(DOM) in water environments is an important component of the global carbon cycle. Under the current urgency to control the pollution of urban rivers in China, exploring the influence of different exogenous and endogenous secondary pollution and weather patterns on river DOM is the premise to better understand the causes of the pollution. In this study, a large city in China was established as the research area, and the underlying water and sediments from 21 sites along urban and suburban rivers, and other water sources were evaluated. The excitation-emission matrix-parallel factor analysis(EEM-PARAFAC) was used to analyze the difference in DOM composition and equivalent in urban rivers polluted by domestic sewage and suburban rivers polluted by aquaculture, agriculture, and livestock breeding. The results showed that:① DOM components in urban and suburban river waters were mainly protein compounds(tyrosine-and tryptophan-like), containing a small amount of humic acid. Humic acid components of anthropogenic origin were found in urban river water; ② The reasons for the formation of DOM components in urban and suburban rivers were completely different. Urban rivers are mainly polluted by domestic sewage and endogenous secondary pollution, resulting in an increase in anthropogenic humic acid components. Suburban rivers are mainly polluted by agricultural wastewater rich in N and P, which promotes endogenous metabolism of autotrophic bacteria and increases protein components, which may be related to the formation of existing DOM characteristics. ③ Rainfall runoff and urban overflow transported exogenous pollutants into rivers, while hydrodynamic factors such as hydraulic agitation affect the distribution of DOM components in underlying water and sediments through physical effects such as dilution.

Detection of Enteric Viruses and Bacterial Indicators in a Sewage Treatment Center and Shallow Water Bay.

The incidence of enteric viruses in treated wastewater and their potential release into the environment or use for agriculture are very critical matters in public health. In our study, PCR (polymerase chain reaction) analysis of enteric viruses was performed on 59 samples of influents and effluents collected from Tubli wastewater treatment plant (Water Pollution Control Center (WPCC)) and Tubli Bay, where the effluents were discharged, in Kingdom of Bahrain during two sampling periods. Four clinically essential waterborne enteric viruses were examined: enterovirus (EV), hepatitis A virus (HAV), astroviruses (AV), and rotaviruses (RV) and compared to standard bacterial and bacteriophages indicators of fecal pollution. Detection rates of EV, AV, HAV, and RV in the influent samples were 100%, 75%, 12.5%, and 12.5%, respectively, while 50% of the effluent samples from Tubli WPCC contained only EV RNA. None of the tested enteric viruses could be detected in any of the samples collected directly from Tubli Bay. Effluent samples from Tubli plant did not show significant seasonal differences. Since detection of enteric viruses genome does not necessarily indicate infectivity, the infectivity of these viruses was evaluated through isolation and growth of indictor bacteria and bacteriophages. High concentration of fecal bacteriological indicators was detected in all effluents samples (100%): 3.20 × 103 cfu/mL for E. coli, 1.32 × 103 cfu/mL for Salmonella spp., and 1.92 × 103 cfu/mL for Shigella spp. E. coli and Salmonella specific bacteriophages were also detected in the effluent samples in high titers. The combined results of PCR and bacterial enumeration point to a probable public health risk via the use of these wastewaters in agriculture or their discharge into the sea. Continuous surveillance of viral and bacterial prevalence and their resistance to sewage disinfection procedures could contribute to a better control of risks associated with the recycling of effluent wastewater and its release into the environment.

Determination of linear alkylbenzenes (LABs) in mangrove ecosystems using the oyster Crassostrea belcheri as a biosensor.

The current study aimed to develop a suitable molecular marker [Linear alkylbenzenes (LABs)] approach for pollution determination in mangrove oysters of peninsular Malaysia. C. belcheri species were collected from rivers of Merbok, Perai, Klang, Muar and PulauMerambong (An Island). The LABs were extracted from C. belcheri and determined using GC-MS. The LABs indices which included I/E, L/S and C13/C12 were applied to describe the sources and biodegradation of LABs. The results revealed that the maximum concentrations were detected in oysters from Klang (27.91 ng g-1dw), while the lowest concentrations were detected in oysters from Merbok (8.12 ng g-1dw). Moreover, I/E ratios varied between 2.83 and 6.40, indicating the secondary treatment effluents being discharged to coastal zones. The results of this study suggested that the oysters absorbed LABs mainly in dissolved phase. Therefore, mangrove oysters are a good biosensor for LABs contamination in the aquatic environment.