Indicators Of Sewage Pollution Research Articles

Persistence of sewage-associated genetic markers in advanced and conventional treated recycled water: implications for microbial source tracking in surface waters.

Genes in sewage-associated microorganisms are widely accepted indicators of sewage pollution in environmental waters. However, DNA persists through wastewater treatment and can reach surface waters when recycled water is discharged, potentially causing false-positive indications of sewage contamination. Previous studies have found that bacterial and viral sewage-associated genes persist through wastewater treatment; however, these studies did not compare different facilities or identify a solution to distinguish sewage from recycled water. In this study, we demonstrated the persistence of bacterial marker genes and the greater persistence of a viral marker gene (CPQ_056 of crAssphage) through varying wastewater treatment facilities. We also aim to provide a tool to confirm sewage contamination in surface waters with recycled water inputs. This work showed that the level of wastewater treatment affects the removal of microorganisms, particularly viruses, and expands our ability to identify sewage in surface waters.

Assessment of Water Quality and Bacteriological Indicators of Sewage Pollution in Bahr El-Baqar Drain, Eastern Nile Delta, Egypt

Assessment of Water Quality and Bacteriological Indicators of Sewage Pollution in Bahr El-Baqar Drain, Eastern Nile Delta, Egypt

Mobility of trace metals and microbiological pollution from dredged sediments to the Gulf of Gabes, Tunisia.

Sediments are periodically dredged from the major ports in the Gulf of Gabes (GG) during maintenance operations. These sediments are dumped near the coats of Sfax and Gabes cities. In the present study, 6 trace metals (Cd, Cu, Cr, Ni, Pb, and Zn) concentrations were assessed in both sediments and column water taken from the different basins of Sfax port. This study is the first to focus on the microbial and microalgae contaminations of Sfax port sediments. The spatial distributions of trace metals in dredged sediments from the different basins of Sfax port show that the maximum concentrations of Cd (13.75µg/g), Cu (892.5µg/g), and Zn (1447µg/g) exceeded the Geode standard thresholds. The same elements, also detected in the water column, exceeded the toxicity thresholds for phytoplankton, shellfish, and algae (Cd 0.095µg/l, Cu 4.52µg/l, and Zn 37µg/l). The presence of coliforms, indicators of sewage pollution, as pathogenic germs (Pseudomonas), was shown through microbiological examinations of the sediments and water column. The microalgae enumeration showed the abundance of dinoflagellate cysts (stressed form) which attests to the presence of severe conditions in Sfax port. Different toxic species were identified as Prorocentrum lima and Alexandrium minutum. The same trace metal sources and abundance in Sfax port and GG sediments suggest the hypothesis of their transfer from their disposal sites in coastal areas to deeper depths in the GG and until Boughrara lagoon (BL). As trace metals, microalgae species were also transferred by hydrodynamic currents inside the GG where they found suitable conditions to their proliferation causing the seawater coloration phenomenon, eutrophication, and degradation of the aquatic system.

Identification of enteroviruses along Lake Victoria shoreline - a potential indicator of sewage pollution.

E n t e r i c v i r u s e s a r e m a i n l y t r a n s m i t t e d b y t h e f a e c a l - o r a l r o u t e a n d h a v e b e e n l i n k e d t o s e v e r a l d i s e a s e s i n c l u d i n g g a s t r o e n t e r i t i s a n d r e s p i r a t o r y i n f e c t i o n s . T h e i r p r e s e n c e i n s u r f a c e w a t e r s h a s b e e n exacerbated by p o l l u t i o n f r o m a v a r i e t y o f p o i n t s o u r c e s s u c h a s s e w a g e d i s c h a r g e . W e s t u d i e d t h e occurrence o f e n t e r o v i r u s e s i n w a t e r s a m p l e s f r o m L a k e V i c t o r i a i n K e n y a t o i n v e s t i g a t e i f t h e r e w a s a l i n k b e t w e e n s e w a g e p o l l u t i o n a n d d e t e c t i o n o f e n t e r o v i r u s e s ( E V s ) t o b u i l d a b a s e l i n e f o r a n enteric viruses monitoring platform for this region. We analysed 216 samples collected over 6 months from six different locations along the Homa Bay Pier. The six sampling locations comprised of three sites (P3, P5, P6) located <500 m from a local sewage treatment plant and pit latrines while three other sites (P1, P2, P4) were located at approximately 0.5 to 3 Km. EVs were concentrated using glass wool adsorption elution protocol and identified using the nested reverse transcription-polymerase chain reaction. The odds ratio was performed to determine whether the location of the sources of sewage pollution near the lake was associated with the EVs contamination. Five out of 108 (5 %) samples collected from the sites (P3, P5 and P6 were EV positive, while 2 % (2/108) of samples from P1, P2 and P4 were EV positive. The presence of the EVs was associated with the distance from the possible sources of faecal contamination (odds ratio 20.28 and 4.86, confidence interval 2.42, and 0.95) for pit latrines and the sewage treatment plant respectively. The result from this study indicates that sewage discharge at the shoreline of Lake Victoria may have been the source of EVs contamination. Data from this study could significantly contribute to informing risk management on sewage pollution in Lake Victoria and it is important to continue monitoring this lake for potentially pathogenic enteric viruses.

Incidence of human associated HF183 Bacteroides marker and E. coli levels in New Orleans Canals

With a focus on five sites in an impaired, densely populated area in the New Orleans area, we investigated the temporal and spatial variability of standard FIB and a marker of human-associated pollution (Bacteroides HF183). With all sites combined, only a weak positive correlation (r = 0.345; p = 0.001) was observed between E. coli and HF183. Also, specific conductivity (r = - 0.374; p < 0.0001) and dissolved oxygen (r = - 0.390; p < 0.0001) were observed to show a weak moderate correlation with E. coli. These correlations increased to moderately negative when HF183 was correlated with specific conductivity (r = - 0.448; p < 0.0001) and dissolved oxygen (r = - 0.455; p < 0.0001). E. coli contamination was generally highest at the sites in the canal that are situated in the most densely populated part of the watershed while HF183 was frequently detected across all sites. E. coli concentrations were significantly higher (p < 0.05) when HF183 was present. HF183 was detected at significantly higher concentrations in samples that exceeded the EPA water quality standard (WQS) than those that did not (p < 0.05). Dissolved oxygen and specific conductivity were significantly lower when E. coli WQS was exceeded or when HF183 was present (p < 0.05). Rainfall impacted E. coli concentrations and HF183 differently at the study sites. While HF183 and E. coli concentrations levels were significantly higher (p < 0.05) if the days prior to sampling had been wet, the frequency of detection of HF183 was unimpacted, as comparable detection rates were recorded during wet and dry weather conditions. Without testing for HF183, it would have been assumed, based on testing for E. coli alone, that human fecal pollution was only associated with densely populated areas and rainfall events. E. coli alone may not be an effective indicator of sewage pollution at the study sites across all weather conditions and may need to be complemented with HF183 enumeration to optimize human fecal pollution identification and management at the watershed level.

Identification of new eligible indicator organisms for combined sewer overflow via 16S rRNA gene amplicon sequencing in Kanda River, Tokyo

Fecal indicator bacteria (FIB) are commonly used to evaluate the pollution impact of combined sewer overflows (CSOs) in urban rivers. Although water quality assessment with FIB has a long tradition, recent studies demonstrated that FIB have a low correlation with pathogens and therefore are not accurate enough for the assessment of potential human hazards in water. Consequently, new eligible and more specific indicators have to be identified, which was done in this study via sequencing of genetic markers from total community DNA. To identify potential microbiome-based indicators, microbial communities in samples from an urban river in Tokyo under different climatic conditions (dry and rainy) were compared with the influent and effluent of three domestic wastewater treatment plants (WWTPs) by analyzing 16 S rRNA gene amplicon libraries. In the first part of this study, physicochemical parameters and FIB quantification with selective culture techniques facilitated the identification of samples contaminated with CSO, sewage, or both. This allowed the grouping of samples into CSO-contaminated and non-contaminated samples, an essential step prior to the microbiome comparison between samples. Increased turbidity, ammonia concentrations, and E. coli [up to (9.37 ± 0.95) × 102 CFU/mL after 11.5 mm of rainfall] were observed in CSO-contaminated river samples. Comparison of dry weather (including WWTP samples) and rainy weather samples showed a reduction in microbial diversity in CSO-contaminated samples. Furthermore, the results of this study suggest Bacteroides spp. as a novel indicator of sewage pollution in surface waters.

Plankton diversity and community characteristics in Danjiangkou Reservoir based on environmental DNA metabarcoding

为了解丹江口库区浮游生物群落的多样性，本研究于2020年7月在丹江口库区丹库、汉库和入库支流等区域共计9个样点采集水体样品，抽滤并提取总DNA样本后，基于18S和16S分子标记进行单分子实时测序，分别探究真核和原核浮游生物群落的多样性及其群落特征.结果表明：（1）真核浮游生物群落的主要优势类群包括节肢动物、链型植物、绿藻门、硅藻门等；本研究在种水平上鉴定出库区分布广泛且相对丰度较大的物种，包括弯曲隐藻、对蛋白核隐藻和空球藻等，它们与库区化学需氧量密切相关；库区化学需氧量是影响真核浮游生物群落格局的重要环境因子.（2）原核浮游生物群落的主要优势类群为变形菌门；原核生物中相对丰度较大的不动杆菌Acinetobacter是污水污染的指示菌群；群落中起重要作用的Limnohabitans与水体的富营养化密切相关；尽管库区蓝藻相对丰度较低，但与蓝藻关系密切的CL500-29_marine_group和hgcI_clade两类细菌在浮游生物群落中也起着重要作用；原核生物群落中的各类物种均指示丹江口水库的水生态健康存在一定风险，需要加强监测以预防生态环境的恶化.（3）丹江口水库不同区域的浮游生物群落异质性较大，tb-RDA分析显示丹江口的浮游生物群落可以分为丹库型、汉库型和入库支流型，其组间差异要大于组内差异.综上所述，丹江口水库的浮游生物群落具有明显的空间异质性，整个库区的群落结构与水体富营养化、水体有机污染和污水污染等方面相关，需要加强对丹江口库区的水生态监测.;The diversity of plankton community in Danjiangkou Reservoir was investigated, water samples were collected from 9 locations in Danku, Hanku and tributary of Danjiangkou Reservoir in July 2020, based on single molecule real-time sequencing. The 18S and 16S gene were used to explore the diversity and community characteristics of eukaryotic and prokaryotic, respectively. Our study has found several aspects:(1) The dominant species of eukaryotic plankton community belong to Arthropoda, Streptophyta, Chlorophyta and Bacillariophyta. We identified the most widely distributed species with high relative abundance, include Cryptomonas curvata, Cryptomonas pyrenoidifera, Eudorina elegans etc., they all associated with the chemical oxygen demand. Thus, the chemical oxygen demand is the key environmental factor for the eukaryotic plankton community. (2) The dominant species of prokaryotic plankton community belong to Proteobacteria. Acinetobacter with high relative abundance is the indicator of sewage pollution, the important species Limnohabitans is associated with eutrophication. Cyanobacteria showed a low relative abundance, but bacteria associated with cyanobacteria like CL500-29_marine_group and hgcI_clade played a pivotal role in the prokaryotic community. Thus, the bioindicator showed the Danjiangkou Reservoir has risk in ecological health and needs further monitor. (3) The plankton community showed a high heterogeneity in different area, the tb-RDA analysis revealed the plankton community in Danjiangkou Reservoir can be divided into three different types, Danku type, Hanku type and tributary type, the difference was higher between different groups than within group, the roots of the difference between these groups lie in the different richness in the community. To sum up, the plankton community showed obvious spatial heterogeneity in Danjiangkou Reservoir, their community structure is associated with water eutrophication, organic pollution, sewage pollution etc., aquatic ecosystem monitoring should be strengthened urgently.

Use of sterols and linear alkylbenzenes as molecular markers of sewage pollution in Southeast Asia.

Southeast Asia has undergone rapid developments in terms of urbanization, economic and population growth. The progress in sewerage treatment infrastructure has not kept pace with such developments. The inadequacy and inefficiency of sewerage systems has prompted the release of untreated sewage into the aquatic environment of Southeast Asia causing many waterborne illnesses since surface water is utilized for recreational, agricultural and aquaculture purposes and, above all, as a source of water intake in Southeast Asia. This paper will review the current data on molecular markers of sewage pollution including sterols and linear alkylbenzenes (LABs) in Southeast Asian aquatic environment to clarify the state of sewage pollution and the competence of sewage treatment plants (STPs) in this area. Despite the importance of sewage pollution research in the region, the number of studies using molecular markers to trace the sources of sewage pollution is limited. So far, indicators of sewage pollution have been investigated in aquatic environments of Indonesia, Vietnam, Malaysia, the Philippines, Thailand, Cambodia and Brunei among Southeast Asian countries. The concentrations and diagnostic ratios of faecal sterols and LABs show the release of untreated and primary treated urban waste into water bodies of these countries. Further studies are required to fill the data gaps in Southeast Asia and come to a better understanding of the trends of sewage pollution in this part of the world. Graphical abstract.

Succession in an intertidal benthic community affected by untreated sewage effluent: A case of study in the SW Atlantic shore

A study of benthic succession related with sewage pollution was conducted in a warm-temperate coastal area of Mar del Plata city, Argentina. The effect of nutrient enrichment and starting period of the succession was tested after cleared space in the intertidal rocky shore benthic community. The time of recovery after a disturbance in enriched sites was considerably lower (20–29weeks) than in non-enriched sites based on the diatom Berkeleya sp. and the polychaete Boccardia proboscidea developed in the early succession stage, and Brachidontes rodriguezii or B. proboscidea occurring with Polysiphonia sp., Petalonia fascia and Ulva spp. developed in the late succession stage of the enriched sites. The very low time at which the community recovered in the enriched environments turned out to be one of the assets of the present study and this parameter can be used as a quick indicator of sewage pollution in the area.

The effect of sewage pollution on the feeding behaviour and diet of Hediste (Nereis diversicolor (O.F. Müller, 1776)) in three estuaries in south-east England, with implications for saltmarsh erosion

Stable isotope analyses of the abundant infaunal polychaete Hediste diversicolor, recognised as an indicator of sewage pollution, support the hypothesis that nutrient enrichment promotes surface deposit feeding, over suspension feeding and predation. At sewage-polluted sites in three estuaries in SE England Hediste mainly consumed microphytobenthos, sediment organic matter and filamentous macroalgae Ulva spp. At cleaner sites Hediste relied more on suspension feeding and consumption of Spartina anglica. There were no consistent differences in Hediste densities between the polluted and cleaner sites, probably because of increased densities at the cleaner sites too, facilitated by the planting of Spartina and nitrogen enrichment there too, including from agricultural run-off. Increased nutrient enrichment and the artificial availability of Spartina have probably increased densities of, and deposit-feeding by, Hediste in the past half-century and contributed indirectly to saltmarsh losses, since deposit-feeding by Hediste has been implicated in recent saltmarsh erosion in SE England.

The response of epilithic diatom assemblages to sewage pollution in mountain streams of the Czech Republic

Background and aim – Mountain streams represent sensitive ecosystems of prime importance for biodiversity conservation. However, the knowledge of the impact of sewage pollution related to intensive recreational exploitation is still limited in these habitats. Our aim was to assess the response of stream diatom assemblages to sewage pollution in the Giant Mountains and the Bohemian Forest, and to find the main factors influencing the community structure. Methods – Epilithic samples from sixteen streams were collected, both in unaffected stream sections and at sites downstream of sewage outflows from mountain cottages or small villages. Basic physical and chemical parameters were measured and relative abundances of diatoms were determined using light microscopy. Key results – A total number of 153 diatom taxa belonging to 44 genera were identified. Based on species data, samples were divided into two groups: the first belonged mainly to sites influenced by pollution, whereas the second consisted of not or slightly affected sites. Both groups were further divided into several subgroups characterised by specific ecological conditions and assemblage composition. Canonical correspondence analysis (CCA) revealed five environmental parameters with significant influence on diatom species composition, some of which were related to sewage pollution (pH, water temperature, discharge volume and concentrations of nitrate nitrogen and organic nitrogen). Conclusions – As a consequence of sewage pollution, oligo- to mesotraphentic taxa were outcompeted by pollution tolerant taxa. However, pollution had no significant influence on diatom diversity, which was similar at sites both upstream and downstream of the outflows. In this study, diatom assemblages performed well as indicators of sewage pollution, and biomonitoring proved to be a useful tool in the detection of environmental stress in mountain streams. Overall, the response of diatom assemblages showed that an increase of recreational activities might significantly alter the ecological status of these ecosystems.

Isotopic and microbial indicators of sewage pollution from Stone Town, Zanzibar, Tanzania

In Stone Town, Zanzibar, sewage treatment is minimal, with a biological oxygen demand reduction to 60% and no removal of bacteria or nutrients. Here, Stone Town’s sewage pollution was studied by measuring Enterococci and NH4+ concentrations in seawater and δ15N of benthic organisms; samples were collected along the Stone Town shoreline and from offshore coral reefs. Public perceptions of sewage pollution were investigated via interviews. Enterococci from the Stone Town shoreline exceeded USEPA guidelines for recreational use. Benthic organisms from two of the four reefs were relatively enriched (δ15N>10‰), indicative of sewage derived N. δ15N values of organisms from Stone Town exceeded 16‰. A strong correlation was found between Enterococci and δ15N across sites, while step-wise regression indicated rainfall and tidal stage as important predictors for bacterial concentrations. These data provide an important impact assessment from which the efficacy of future policy and management change can be assessed.

Statistical assessment of seafront and beach water quality of Mumbai, India

The water quality of seafronts and beaches of Mumbai is under pressure and deteriorating due to discharge of partially treated sewage and wastewater through point and nonpoint sources. The objective of the study was to assess the water quality and to correlate physico-chemical and bacteriological parameters for establishing relationship, association and dependence on each other. The water quality parameters were selected as per SW II standards specified by Central Pollution Control Board, India and nutrient parameters as strong indicators of sewage pollution. Box and whisker plots were generated for evaluating spatio temporal variation of water quality which suggest influence of organic pollution mostly at Mahim and Dadar in the form of outliers and extremes. Pearson's correlations were estimated between parameters and found significant correlation with each other indicating influence of sewage on water quality. The water quality of beaches and seafronts were found unsafe for recreational purposes. The study suggested that designated water quality can be achieved by restricting nonpoint source through improvement in wastewater collection systems, appropriate level of treatment and proper disposal.

A real-time qPCR assay for the detection of the nifH gene of Methanobrevibacter smithii, a potential indicator of sewage pollution

To develop a quantitative, real-time PCR assay to detect the nifH gene of Methanobrevibacter smithii. Methanobrevibacter smithii is a methanogenic archaea found in the intestinal tract of humans that may be a useful indicator of sewage pollution in water. Quantification standards were prepared from Meth. smithii genomic DNA dilutions, and a standard curve was used to quantify the target gene and calculate estimated genome equivalency units. A competitive internal positive control was designed and incorporated into the assay to assess inhibition in environmental extracts. Testing the assay against a panel of 23 closely related methanogen species demonstrated specificity of the assay for Meth. smithii. A set of 36 blind water samples was then used as a field test of the assay. The internal control identified varying levels of inhibition in 29 of 36 (81%) samples, and the Meth. smithii target was detected in all water samples with known sewage input. The quantitative PCR assay developed in this study is a sensitive and rapid method for the detection of the Meth. smithii nifH gene that includes an internal control to assess inhibition. Further research is required both to better evaluate host specificity of this assay and the correlation with human health risks. This research is the first description of the development of a rapid and sensitive quantitative assay for a methanogenic archaeal indicator of sewage pollution.

Detection of the nifH gene of Methanobrevibacter smithii: a potential tool to identify sewage pollution in recreational waters

The goal of this study was to develop and test the efficacy of a PCR assay for the environmental detection of the nifH gene of Methanobrevibacter smithii, a methanogen found in human faeces and sewage. PCR primers for the nifH gene of M. smithii were designed, tested and used to detect the presence or absence of this organism in faecal and environmental samples. Specificity analysis showed that the Mnif primers amplified products only in M. smithii pure culture strains (100%), human faeces (29%), human sewage samples (93%) and sewage-contaminated water samples (100%). No amplification was observed when primers were tested against 43 bacterial stock cultures, 204 animal faecal samples, 548 environmental bacterial isolates and water samples from a bovine waste lagoon and adjacent polluted creek. Sequencing of PCR products from sewers demonstrated that a 222-bp product was the nifH gene of M. smithii. The minimal amount of total DNA required for the detection of M. smithii was 10 ng for human faeces, 10 ng for faecally contaminated water and 5 ng for sewage. Recreational water seeded with M. smithii established a lower detection limit of 13 cells ml(-1). The Mnif assay developed during this investigation showed successful detection of M. smithii in individual human faecal samples, sewage and sewage-contaminated water but not in uncontaminated marine water or bovine-contaminated waters. The Mnif assay appears to be a potentially useful method to detect sewage-polluted coastal waters. This study was the first to utilize methanogens as an indicator of sewage pollution. Mnif PCR detection of M. smithii was shown to be a rapid, inexpensive and reliable test for determining the presence or absence of sewage pollution in coastal recreational waters.

Application ofBacteroides fragilis phage as an alternative indicator of sewage pollution in Tampa Bay, Florida

Traditional fecal coliform bacterial indicators have been found to be severely limited in determining the significance and sources of fecal contamination in ambient waters of tropical and subtropical regions. The bacteriophages that infectBacteroides fragilis have been suggested as better fecal indicators and at least one type may be human specific. In this study, the phages that infectB. fragilis host RYC2056 (RYC), including phage B56-3, and host ATCC 51477-HSP40 (HSP), including the human specific phage B40-8, were evaluated in the drainage basins of Tampa Bay, 7 samples (n=62), or 11%, tested positive for the presence of phages infecting the host HSP, whereas 28 samples, or 45%, tested positive using the host RYC. A survival study was also done to compare the persistence of phages B56-3 and B40-8 to MS2 coliphage in seawater at various temperatures. The decay rates for MS2 were 0.239 log10 d−1 at 10°C, but increased to 0.896 at 20°C and 2.62 log10 d−1 at 30°C. The twoB. fragilis phages persisted much longer in the seawater compared to the coliphage and showed little variation between the temperatures. All sewage influents sampled from area wastewater treatment plants contained phages that infected the twoB. fragilis hosts at levels from 1.2×104 to 1.11×105 pfu 100 ml−1 for host RYC and 67 to 350 pfu 100 ml−1 for host HSP. Of the 7 chlorinated effluent samples tested, 3 were positive for the presence of the phage using the host RYC and the phage enrichment method, with levels estimated to be <10 pfu 100 ml−1. No phages were detected using the host HSP in the treated sewage effluent. Coliphages were found in 3 of the 7 effluent samples at a range of 30 to 1.2×103 pfu 100 ml−1.

The influence of environmental factors on microbiological indicators of coastal water pollution

The relationships between bacteriological and viral indicators of sewage pollution (TC, FC, E coli, FS, Salmonella, somatic coliphages and F-RNA phages) and environmental variables in coastal water and weather were studied at three beaches in San Sebastian, the Basque Country. The microbiological indicators in bathing water presented high counts associated with the following conditions: early morning, overcast skies, low and high tides, groundswell, intense turbidity and the presence of flotsam (P = &amp;lt;0.05). Coliphage density was significantly related (P = &amp;lt;0.05) to cloud cover, groundswell and flotsam. Correlations between microbiological indicators proved high (0.62 ≤ r ≤ 0.90, P = &amp;lt;0.001). The percentage of Salmonella presented significant (&amp;lt;0.05), albeit low (r &amp;lt; 0.4), correlations with all microbiological parameters. Somatic coliphages also revealed highly significant (0.32 ≤ r ≤ 0.66) correlations (P = &amp;lt;0.001). Those obtained for F-RNA phages, in contrast, were low (r ≤ 0.33). The equations obtained using a multiple regression analysis with a view to predicting microbiological, viral, and Salmonella indicator density demonstrated that environmental variables facilitate the construction of highly significant equations, but that these have low predictive capability (R2 = &amp;lt;0.50).

The influence of environmental factors on microbiological indicators of coastal water pollution

The relationships between bacteriological and viral indicators of sewage pollution (TC, FC, E coli, FS, Salmonella, somatic coliphages and F-RNA phages) and environmental variables in coastal water and weather were studied at three beaches in San Sebastian, the Basque Country. The microbiological indicators in bathing water presented high counts associated with the following conditions: early morning, overcast skies, low and high tides, groundswell, intense turbidity and the presence of flotsam (P = <0.05). Coliphage density was significantly related (P = <0.05) to cloud cover, groundswell and flotsam. Correlations between microbiological indicators proved high (0.62 ≤ r ≤ 0.90, P = <0.001). The percentage of Salmonella presented significant (<0.05), albeit low (r < 0.4), correlations with all microbiological parameters. Somatic coliphages also revealed highly significant (0.32 ≤ r ≤0.66) correlations (P = <0.001). Those obtained for F-RNA phages, in contrast, were low (r ≤ 0.33). The equations obtained using a multiple regression analysis with a view to predicting microbiological, viral, and Salmonella indicator density demonstrated that environmental variables facilitate the construction of highly significant equations, but that these have low predictive capability (R2 = <0.50).

An investigation into parametric relationships between enterovirus and faecal indicator organisms in the coastal waters of England and Wales

Previous research has resulted in conflicting conclusions concerning possible statistical relationships between bacterial indicator and enterovirus concentrations in marine waters. Results have suggested either highly significant relationships or no significant correlation. To examine these relationships further, large compliance assessment data sets for identified bathing waters on the English and Welsh coast, between 1988 and 1992, were extended to include enterovirus and faecal streptococci counts in addition to total and faecal coliform data. The suitability of these data for parametric correlation analysis was assessed by examining the nature of the statistical distributions of raw data and residual values from regression analyses. The data were acceptable for parametric analysis when (i) zero enterovirus samples were excluded and (ii) enterovirus counts were logarithmically transformed. The analysis of over 690 data pairs produced positive Pearson correlation coefficients between coliforms, faecal coliforms, faecal streptococci and enterovirus concentrations. Though the correlations were significant ( P < 0.001, i.e. > 99.9% confidence) they were low ( r < 0.5). The amount of variance in enterovirus concentration explained by bacterial concentration was only 15–16%. Relationships were similar for each bacterial determinand. Correlations above successive quartile values of bacterial concentration revealed no threshold effect in these relationships. These results suggest poor statistical relationships between concentrations of bacterial indicators of sewage pollution and enterovirus in marine waters resulting in a low predictive capability.

Detection of enteroviruses in marine waters by direct RT-PCR and cell culture

Sewage outfalls and storm water runoff introduces pathogenic human enteric viruses into marine coastal waters, which may pose a potential public health risk. Although members of the enterovirus group have been suggested as possible indicators of sewage pollution in marine waters, the lack of rapid, sensitive and cost effective methods have prevented routine monitoring in the United States. This study compared traditional cell culture and direct RT-PCR (reverse transcriptase-polymerase chain reaction) amplification for detection of an enterovirus. Poliovirus could be recovered from 100 L of artificial seawater with an average efficiency of 77%, using adsorption and elution from electronegative filters. Viruses were eluted from the filters with 1.5% beef extract for viruses (BEV) adjusted to pH 9.5 and reconcentrated by organic flocculation to a volume of 30 mL. Substances which interfered with detection by RT-PCR were removed by treatment of the concentrates with sephadex and chelex resins. Direct RT-PCR could detect 2.5 and 0.025 PFU (plaque forming units) for single (25 cycles) and double PCR (2 × 25 cycles) in 10 μL of pure culture poliovirus samples, respectively. These methods are currently being applied to assess the occurrence of enteroviruses at marine bathing beaches influenced by sewage discharges.