Sewage Water Samples Research Articles

Bacterial flora analysis of coliforms in sewage, river water, and ground water using MALDI-TOF mass spectrometry

ABSTRACTThe aim of this study was to rapidly and effectively analyze coliforms, which are the most fundamental indicators of water quality for fecal pollution, using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Coliform bacteria were isolated from municipal sewage, river water, and groundwater. For each sample, 100 isolates were determined by MALDI-TOF MS. In addition, these same 100 isolates were also identified via 16S rRNA gene sequence analysis. Obtained MALDI-TOF MS data were compared with the 16S rRNA sequencing analysis, and the validity of MALDI-TOF MS for classification of coliform bacteria was examined. The concordance rate of bacterial identification for the 100 isolates obtained by MALDI-TOF MS analysis and 16S rRNA gene sequence analysis for sewage, river water, and ground water were 96%, 74%, and 62% at the genus level, respectively. Among the sewage, river water, and ground water samples, the coliform bacterial flora were distinct. The dominant genus of coliforms in sewage, river water, and groundwater were Klebsiella spp., Enterobacter spp., and Serratia spp., respectively. We determined that MALDI-TOF MS is a rapid and accurate tool that can be used to identify coliforms. Therefore, without using conventional 16S rRNA sequencing, it is possible to rapidly and effectively classify coliforms in water using MALDI-TOF MS.

Facile preparation of silver nanoparticle decorated chitosan cryogels for point-of-use water disinfection

In this study, silver nanoparticle decorated chitosan (CS/Ag NP) cryogels were fabricated through a simple freeze-drying process for point-of-use (POU) water disinfection. The CS/Ag NP cryogels showed high porosity, good mechanical properties, an excellent water absorption capability, and most importantly, an efficient bactericidal feature. The absorption capacity for water was found to be 47g/g, approximately 90% of which was recovered by simple squeezing. Three different sizes of Ag NPs were compared regarding their bactericidal capability against both Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis). Under optimum conditions, a 3 log reduction of bacteria was observed by holding the bacteria suspension (108 colony forming units (cfu)/mL) in the cryogels for 5min. Reduction was further increased to a 4 log when the contact time was doubled. The silver content in the cryogels was found to only be 7.5mg/g. Furthermore, the total Ag in processed water was found to only be 22μg/L, half of the safety limit set by China (<50μg/L). The bactericidal effectiveness of the material for real surface water samples was also demonstrated by treating water samples with different water quality matrices, including lake water and sewage water samples. In all three treated lake water samples, both the total bacteria and E. coli met the regulations for drinking water in China (<100cfu/mL for total bacteria and negative for E. coli). CS/Ag NP cryogels can be used for drinking water disinfection during disaster relief and in contingency water supply applications.

Quantitative CrAssphage PCR Assays for Human Fecal Pollution Measurement.

Environmental waters are monitored for fecal pollution to protect public health and water resources. Traditionally, general fecal-indicator bacteria are used; however, they cannot distinguish human fecal waste from other animal pollution sources. Recently, a novel bacteriophage, crAssphage, was discovered by metagenomic data mining and reported to be abundant in and closely associated with human fecal waste. To confirm bioinformatic predictions, 384 primer sets were designed along the length of the crAssphage genome. Based on initial screening, two novel crAssphage qPCR assays (CPQ_056 and CPQ_064) were designed and evaluated in reference fecal samples and water matrices. The assays exhibited high specificities (98.6%) when tested against an animal fecal reference library, and crAssphage genetic markers were highly abundant in raw sewage and sewage-impacted water samples. In addition, CPQ_056 and CPQ_064 performance was compared to HF183/BacR287 and HumM2 assays in paired experiments. Findings confirm that viral crAssphage qPCR assays perform at a similar level to well-established bacterial human-associated fecal-source-identification approaches. These new viral-based assays could become important water quality management and research tools.

An organically modified silica aerogel for online in-tube solid-phase microextraction

Aerogels have received considerable attentions because of its porous, high specific surface, unique properties and environmental friendliness. In this work, an organically modified silica aerogel was functionalized on the basalt fibers (BFs) and filled into a poly(ether ether ketone) (PEEK) tube, which was coupled with high performance liquid chromatography (HPLC) for in-tube solid-phase microextraction (IT-SPME). The aerogel was characterized by scanning electron microscopy (SEM) and fourier transform infrared spectrometry (FT-IR). The extraction efficiency of the tube was systematically investigated and shown enrichment factors from 2346 to 3132. An automated, sensitive and selective method was developed for the determination of five estrogens. The linear range was from 0.03 to 100μgL−1 with correlation coefficients (r) higher than 0.9989, and low detection limits (LODs) were 0.01–0.05μgL−1. The relative standard deviations (RSDs) for intra-day and inter-day were less than 4.5% and 6.7% (n=6), respectively. Finally, the analysis method was successfully applied to detect estrogens in sewage and emollient water samples.

Enhanced removal of phosphate and nitrate ions from aqueous media using nanosized lanthanum hydrous doped on magnetic graphene nanocomposite

A novel nanocomposite adsorbent based on nanosized lanthanum hydroxide doped onto magnetic reduced graphene oxide (MG@La) was synthesized and used for removal of phosphate and nitrate ions from river and sewage media. The composition, surface properties and morphology of the as prepared adsorbent were studied using Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). The influence of main parameters on the efficiency of removal process including adsorbent dosage, salt addition, solution pH, contact time, and concentration of the analytes were thoroughly investigated. The validity of the experimental process was checked by the adsorption isotherm and adsorption kinetics models. The obtained data were well fitted to Langmuir isotherm and pseudo-second-order kinetic models. The developed adsorbent showed high adsorption capacities of 116.28 mg g−1 and 138.88 mg g−1 for phosphate and nitrate ions, respectively. Additionally, Langmuir isotherm and free energy were suggested monolayer pattern and physisorption mechanism for adsorption process, respectively. Finally, the field application of newly synthesized MG@La provided high removal efficiencies (74%–90%) for phosphate and nitrate ions in real river and sewage water samples.

Presence of Methicillin Resistant Staphylococcus aureus (MRSA) in sewage treatment plant

The presence of antibiotic resistant bacteria and antibiotic resistance genes in rural sewage treatment plants are not well reported in the literature. The aim of the present study was to study the frequency occurrence of Methicillin Resistant Staphylococcus aureus (MRSA) in a rural sewage treatment plant. This study was conducted using raw sewage as well as treated sewage from a small town sewage treatment plant in rural southeast Louisiana of USA. Results showed the presence of MRSA consistently in both raw and treated sewage. The presence of mecA gene responsible for methicillin resistance was confirmed in the raw and treated sewage water samples.

Laboratory Surveillance of Polio and Other Enteroviruses in High-Risk Populations and Environmental Samples.

In the context of poliomyelitis eradication, a reinforced supplementary laboratory surveillance of enteroviruses was implemented in Greece. Between 2008 and 2014, the Hellenic Polioviruses/Enteroviruses Reference Laboratory performed detailed supplementary surveillance of circulating enteroviruses among healthy individuals in high-risk population groups, among immigrants from countries in which poliovirus is endemic, and in environmental samples. In total, 722 stool samples and 179 sewage water samples were included in the study. No wild-type polioviruses were isolated during these 7 years of surveillance, although two imported vaccine polioviruses were detected. Enterovirus presence was recorded in 25.3 and 25.1% of stool and sewage water samples, respectively. Nonpolio enteroviruses isolated from stool samples belonged to species A, B, or C; coxsackievirus A24 was the most frequently identified serotype. Only enteroviruses of species B were identified in sewage water samples, including four serotypes of echoviruses and four serotypes of coxsackie B viruses. Phylogenetic analysis revealed close genetic relationships among virus isolates from sewage water samples and stool samples, which in most cases fell into the same cluster. To the best of our knowledge, this is the first study to compare enterovirus serotypes circulating in fecal specimens of healthy individuals and environmental samples, emphasizing the burden of enterovirus circulation in asymptomatic individuals at high risk. Given that Greece continues to receive a large number of short-term arrivals, students, migrants, and refugees from countries in which poliovirus is endemic, it is important to guarantee high-quality surveillance in order to maintain its polio-free status until global eradication is achieved.IMPORTANCE This article summarizes the results of supplementary poliovirus surveillance in Greece and the subsequent characterization of enteroviral circulation in human feces and the environment. The examination of stool samples from healthy refugees and other individuals in "high-risk" groups for poliovirus enables the identification of enterovirus cases and forms the basis for further investigation of the community-level risk of viral transmission. In addition, the examination of composite human fecal samples through environmental surveillance links poliovirus and nonpoliovirus isolates from unknown individuals to populations served by the sewage or wastewater system. Supplementary surveillance is necessary to comply with the prerequisites imposed by the World Health Organization for monitoring the emergence of vaccine-derived polioviruses, reemergence of wild polioviruses, or disappearance of all vaccine-related strains in order for countries such as Greece to maintain their polio-free status and contribute to global poliovirus eradication.

Isolation and Identification of Enteroviruses from Sewage and Sewage-Contaminated Water Samples from Ibadan, Nigeria, 2012-2013

In 2010, we described sewage contaminated water (SCW) bodies that consistently yielded enteroviruses (EVs) in enterovirus surveillance (ES) sites in Lagos, Nigeria. By 2012, we demonstrated the presence and circulation of Wild Poliovirus 3 (WPV3) in these ES sites. Here we describe ES sites that consistently yield EVs in Ibadan metropolis southwest Nigeria. Twenty-five ES samples were collected by grab method from nine sites between October, 2012 and March, 2013. Samples were concentrated and four (RD, HEp2C, MCF-7 and L20B) different cell lines used for virus isolation from the concentrates. Isolates were subjected to RNA extraction, cDNA synthesis, PanEnterovirus 5l-UTR and VP1 assays. Unidentifiable isolates were further subjected to species-specific RTPCR assays. Amplicons were sequenced, isolates identified and subjected to phylogenetic analysis. Twenty-five isolates were recovered from 8 (32%) of the samples collected. Twenty-three of the isolates were identified as EVs by the PanEntero5l-UTR assay. Thirteen (57%) of the 23 EVs were positive for the VP1 assay, and identified as Coxsackievirus B3 (CVB3) (1 isolate), CVB6 (1 isolate), E6 (2 isolates), E7 (5 isolates), E11 (1 isolate), E12 (1 isolate) and E13 (2 isolates). None and 2 (25%) of the remaining isolates were positive for the EV-B and EV-C assays, respectively. The 2 EV-C positive enteroviruses were isolated on MCF-7. This study describes three very productive ES sites, and documents the presence of CVB3, CVB6, E6, E7, E11, E12 and, E13 in Ibadan, Nigeria. Including other cell lines in EV isolation protocols can broaden the diversity of EV types recoverable.

Membrane protected C18 coated stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet detection for the determination of non-steroidal anti-inflammatory drugs in water samples

By wrapping a porous membrane around the coated stir bar, a novel membrane protected stir bar sorptive extraction (MPSBSE) was proposed to filter out the high molecular weight interferences (such as humic acid), resulting in the analysis of real environmental water samples without filtration or centrifugation. Hydrophilic and hydrophobic membranes were compared and hydrophobic polytetrafluoroethylene (PTFE) membrane impregnated with methanol was employed to protect the C18 coated stir bar. The impregnated methanol improves the transfer of target analytes from sample solution to the pores and lumen of the membrane, and then to the coated stir bar inside. By combining C18-MPSBSE with HPLC-UV, a method was proposed for the direct determination of two common non-steroidal anti-inflammatory drugs, Ketoprofen (KEP) and Naproxen (NAP) in complex water samples. Under the optimized conditions, the limit of detections of KEP and NAP are 7.89, 9.52μgL−1 in the waste water and 7.69, 6.90μgL−1 in the pure water, respectively, with the enrichment factors of 32.0–49.1-fold. Besides, the lifetime of the prepared C18 stir bar protected by PTFE membrane (50 times) is longer than that of C18 stir bar without membrane protection (20 times), indicating that the friction damage of SBSE coating during extraction was effectively avoided. The developed method was successfully applied to the analysis of KEP and NAP in domestic sewage and campus lake water samples.

An Optimized Method for Quantification of Pathogenic Leptospira in Environmental Water Samples.

Leptospirosis is a zoonotic disease usually acquired by contact with water contaminated with urine of infected animals. However, few molecular methods have been used to monitor or quantify pathogenic Leptospira in environmental water samples. Here we optimized a DNA extraction method for the quantification of leptospires using a previously described Taqman-based qPCR method targeting lipL32, a gene unique to and highly conserved in pathogenic Leptospira. QIAamp DNA mini, MO BIO PowerWater DNA and PowerSoil DNA Isolation kits were evaluated to extract DNA from sewage, pond, river and ultrapure water samples spiked with leptospires. Performance of each kit varied with sample type. Sample processing methods were further evaluated and optimized using the PowerSoil DNA kit due to its performance on turbid water samples and reproducibility. Centrifugation speeds, water volumes and use of Escherichia coli as a carrier were compared to improve DNA recovery. All matrices showed a strong linearity in a range of concentrations from 106 to 10° leptospires/mL and lower limits of detection ranging from <1 cell /ml for river water to 36 cells/mL for ultrapure water with E. coli as a carrier. In conclusion, we optimized a method to quantify pathogenic Leptospira in environmental waters (river, pond and sewage) which consists of the concentration of 40 mL samples by centrifugation at 15,000×g for 20 minutes at 4°C, followed by DNA extraction with the PowerSoil DNA Isolation kit. Although the method described herein needs to be validated in environmental studies, it potentially provides the opportunity for effective, timely and sensitive assessment of environmental leptospiral burden.

Legionella saoudiensis sp. nov., isolated from a sewage water sample.

A Gram-stain-negative, bacilli-shaped bacterial strain, LS-1T, was isolated from a sewage water sample collected in Jeddah, Saudi Arabia. The taxonomic position of strain LS-1T was investigated using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences and those of four other genes indicated that strain LS-1T belongs to the genus Legionella in the family Legionellaceae. Regarding the 16S rRNA gene, the most closely related species are Legionella rowbothamii LLAP-6T (98.6 %) and Legionella lytica L2T (98.5 %). The mip gene sequence of strain LS-1T showed 94 % sequence similarity with that of L. lytica L2T and 93 % similarity with that of L. rowbothamii LLAP-6T. Strain LS-1T grew optimally at a temperature of 32 °C on a buffered charcoal yeast extract (BCYE) agar plate in a 5 % CO2 atmosphere and had a flagellum. The combined phylogenetic, phenotypic and genomic sequence data suggest that strain LS-1T represents a novel species of the genus Legionella, for which the name Legionella saoudiensis sp. nov. is proposed. The type strain is LS-1T (=DSM 101682T=CSUR P2101T).

Amino-calixarene-modified graphitic carbon as a novel electrochemical interface for simultaneous measurement of lead and cadmium ions at picomolar level

Amino-calixarene-derivatized graphitic carbon electrode has been used in the simultaneous quantification of lead and cadmium ions at picomolar level. The graphitic carbon has been chemically modified using amino-calixarene as an indicator molecule through microwave irradiation, and it has been characterized by NMR, mass, and Fourier transform infrared spectroscopy (FTIR) techniques. The proposed sensor has shown linearity in the concentration range 10–120 pM with detection limits of 3.3 and 3.5 pM for lead and cadmium, respectively. The proposed sensor has been successfully applied to quantify lead and cadmium levels in battery effluents, alloy materials, and sewage water sample matrices. The results obtained by the proposed sensor are in agreement with the results of the standard protocols.

Мікробіологічна характеристика стічних вод м. Києва та оцінка екологічної придатності їх для використання в землеробстві

Мікробіологічна характеристика стічних вод м. Києва та оцінка екологічної придатності їх для використання в землеробстві

Frequent Detection and Genetic Diversity of Human Bocavirus in Urban Sewage Samples.

The prevalence and genetic diversity of human bocaviruses (HBoVs) in sewage water samples are largely unknown. In this study, 134 raw sewage samples from 25 wastewater treatment plants (WTPs) in Italy were analyzed by nested PCR and sequencing using species-specific primer pairs and broad-range primer pairs targeting the capsid proteins VP1/VP2. A large number of samples (106, 79.1%) were positive for HBoV. Out of these, 49 were classified as HBoV species 2, and 27 as species 3. For the remaining 30 samples, sequencing results showed mixed electropherograms. By cloning PCR amplicons and sequencing, we confirmed the copresence of species 2 and 3 in 29 samples and species 2 and 4 in only one sample. A real-time PCR assay was also performed, using a newly designed TaqMan assay, for quantification of HBoVs in sewage water samples. Viral load quantification ranged from 5.51E+03 to 1.84E+05GC/L (mean value 4.70E+04GC/L) for bocavirus 2 and from 1.89E+03 to 1.02E+05GC/L (mean value 2.27E+04GC/L) for bocavirus 3. The wide distribution of HBoV in sewages suggests that this virus is common in the population, and the most prevalent are the species 2 and 3. HBoV-4 was also found, representing the first detection of this species in Italy. Although there is no indication of waterborne transmission for HBoV, the significant presence in sewage waters suggests that HBoV may spread to other water environments, and therefore, a potential role of water in the HBoV transmission should not be neglected.

Isolation and Characterization of Lytic Bacteriophages infecting Staphylococcus epidermidis

The Staphylococcus epidermidis isolates were obtained during a period extended between September 2014 and January 2015, depending on biochemical tests and VITEK 2 system. Several sewage water samples were assayed using a plaque assay of double agar overlay as a source of S. Epidermidis phages. The bacteriophages were described depending on plaques size and shapes. Phage 1 was the most predominant in the bacterial lawn and able to infect other S. species such as S. aureus. Therefore, it was decided to study the effect of temperature on its original titer. The results revealed a gradual decrease in the phage titer with increasing dilution number. Each temperature at several incubation periods, significantly vary depending on phage titer. The optimum temperature was 40 ° C, while the 80 ° C was represented the inhibitor temperature. L.S.D. at level (0.05) for interaction was 39.552. The pH 6.5 – 7.5 were represented the optimal pH for the best phage activity while the phage titer beginning to decline in above and below this range of optimal pH , L.S.D. at level 0.05 was 17.898. In conclusion, our study found that Phage1 was considered as predominant phage because of their ability to infect other Staphylococci species such as S. Aureus.

Understanding the distribution, degradation and fate of organophosphate esters in an advanced municipal sewage treatment plant based on mass flow and mass balance analysis

Although organophosphate esters (OPEs) in the ambient environment are from sewage treatment plants due to the discharge of effluent and application of sludge, the distribution, degradation and fate of OPEs in advanced municipal sewage treatment plants remain unclear. This work focused on the use of mass flow and mass balance analysis to understand the behaviors and fate of 14 OPEs in an advanced municipal sewage treatment plant. OPEs were detected in all sewage water and sludge samples with total OPEs (ΣOPEs) concentrations of 1399±263ng/L in raw sewage aqueous phase, 833±175ng/L in tertiary effluent aqueous phase, and 315±89ng/g dry weight in dewatered sludge. The dissolved concentrations of ΣOPEs significantly decreased during biological treatment, whereas negligible decrease was observed in mechanical and physical-chemical treatments. For individual OPE, the chlorinated tris(2-chloroethyl) phosphate (TCEP) and tris(2-chloroisopropyl) phosphate (TCPP) did not decrease but increased during both biological treatment and physical-chemical treatment. Mass flow analysis indicated the total removal efficiency of ΣOPEs in aqueous phase was 40.5%, and the polarity-specific removal efficiencies for individual OPE were positively related to their solid-water partition coefficients (Kd). Furthermore, mass balance results showed that 53.1% and 6.3% of the initial OPE mass flow were eventually transferred to the effluents and dewatered sludge, respectively, while the remaining 39.9% and 0.7% were lost due to biodegradation and physical-chemical treatment, respectively. It was indicated that the activated sludge treatment system with anaerobic/anoxic/aerobic bioreactors was a major factor in the removal of OPEs from the raw sewage, while transfer to dewatered sludge governed by hydrophobic interactions was limited during the sewage treatment. Meanwhile, the degradation difference of OPEs in activated sludge treatment was more related with their molecular structure over their hydrophobicity.

Determination of 2,4,6-Trinitrotoluene in Wastes and Sewage Water from Mining Industry by Chromato-Mass Spectrometry

A method for determination of 2,4,6-trinitrotoluene in geoenvironmental subjects by gas chromatography with mass-spectrometric detection was proposed. The distribution of 2,4,6-trinitrotoluene in wastes and sewage water samples from mining plants was studied. The presence of this compound in surface water was established. Other nitrogen-containing compounds, in particular, 2-amino-4,6-dinitrotoluene and&lt;br /&gt;2,4,-dinitrotoluene, were also identified in the studied samples.&lt;br /&gt;The 2,4,6-trinitrotoluene (TNT) is the most important shattering explosive used for blasting out. This compound is highly toxic and stable to biodegradation. The TNT belongs to the second hazard class (highly hazardous); its maximum permissible concentration (MPC) in drinking water sources was strongly restricted, from 0.5 to 0.01 mg/L. A method for determination of 2,4,6-trinitrotoluene in surface water, sewage water and wastes by gas chromatography with mass-spectrometric detection has been developed. The TNT calibration curve was shown to be linear over the concentration range of 1.6-160 μg/mL, and the correlation factor of the line was equal to 0.997. The distribution of 2,4,6-trinitrotoluene in sewage water and wastes from mining plants has been studied. Mine water in the case of underground mining has high TNT concentrations, which cannot be decreased by the existing traditional methods of sewage water treatment. TNT is detected also in surface water after mine water disposal. Note that the TNT concentrations can exceed many times the maximum permissible concentrations prescribed for water works system.&lt;br /&gt;2-amino-4,6-dinitrotoluene and 2,4,-dinitrotoluene, which can be considered as products of TNT metabolism, were also identified in the studied samples. The developed method and results of the present study make it possible to introduce the quantitative&lt;br /&gt;determination of TNT and its metabolites into the programs for monitoring of surface water, sewage water and wastes in the mining plant sites in different countries as well in Russia, namely in Kuzbass.

Algoriella xinjiangensis gen. nov., sp. nov., a new psychrotolerant bacterium of the family Flavobacteriaceae.

An aerobic, Gram-stain negative, non-spore-forming and psychrotolerant bacterium, designated strain XJ109(T), was isolated from a sewage water sample collected from Xinjiang Uigur Autonomous Region, China. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain XJ109(T) represents a novel member of the family Flavobacteriaceae. The strain showed 95.5 % similarity with the 16S rRNA gene sequence of Empedobacter brevis LMG 4011(T), 95.4% with Chishuiella changwenlii BY4(T), 95.3% with Empedobacter falsenii NF 993(T) and 92.3% with Weeksella virosa DSM 16922(T). Strain XJ109(T) showed the common phenotypic and chemotaxonomic characteristics of the family Flavobacteriaceae, containing menaquinone-6 (MK-6) as the predominant respiratory quinone and iso-C17:0 3OH and iso-C15:0 as the major fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, one unidentified phospholipid and two unidentified lipids. The genomic DNA G+C content was 38.0 mol%. Strain XJ109(T) was positive for catalase and oxidase activities, and it was observed to grow at 4-30 °C (optimal 16-20 °C), pH 6.5-10.0 (optimal 7.0-7.5) and in media containing 0-2.0% (w/v) NaCl (optimal 0.5 %). On the basis of the polyphasic evidence presented, strain XJ109(T) is considered to represent a novel genus and species of the family Flavobacteriaceae, for which the name Algoriella xinjiangensis gen. nov., sp. nov. is proposed. The type strain is XJ109(T) (=CGMCC 1.10229(T)=JCM 16590(T)).

Fluorescence cadmium sulfide nanosensor for selective recognition of chromium ions in aqueous solution at wide pH range

Chromium is recognized as a serious environmental pollutant because of high toxicity and carcinogenic properties. In this paper, we have developed cadmium sulfide quantum dots (CdS QDs) based fluorescence sensor for sensitive and selective detection of chromium ions. CdS QDs were synthesized by wet chemical method using pectin biopolymer as capping agent and taurine as an antioxidant. The fluorescence emission intensity of CdS QDs at 450nm was selectively quenched by chromium ions, whereas other cations and anions showed negligible changes. The fluorescence intensity of CdS QDs is linearly proportional to the chromium concentration from 0.016 to 0.260μM with a detection limit of 16×10−9M. The proposed sensor recognizes chromium ion at a wide range of pH from 4 to 10. In addition, CdS QDs were also used to detect chromium ions in biological fluid, sewage water, pond water and tap water samples, with low interference.

DISTRIBUTION OF HAEMOLYTIC THIOBACILLI IN SEWAGE SAMPLES

Sulphur is one of the essential plant nutrients and it contributes to yield and quality of crops. Thiobacillus play an important role in sulphur oxidation in soil and domestic wastewater.The present study is sought to understand the frequency of Thiobacillus in sewage water samples collected from hospital and domestic area.Distribution of sulphur oxidizing bacteria were analysed by using modified Thiobacilli agar. Five isolates were selected and analysed their selected putative virulence properties phenotypically.Also they were showed biocompatible within the group of the Thiobacilli.The extracellular products (culture supernatant) of Thiobacilli showed a substantial level of haemolytic activity and antagonistic activity. Among the isolates from sewage sources, TB-D1 and TB-D2 produced higher level of bacteriocin against pathogenic bacteria due to the formation of maximum inhibition zone. It reveals that the bacteriocin from Thiobacillus showed the elevated antagonistic activity against most of the pathogenic bacteria, as we tested.The strains TB-D4 and TB-D5 showed beta and alpha haemolysis, it might have virulent properties and cause infection in human and animals.The strain TB-D5 showed the maximum inhibitions while compared with others. It is visibly showing presence of virulence factors in the extracellular metabolites of Thiobacilli.