Sewage Treatment Works Effluent Research Articles

Spatial distribution of organic contaminants in three rivers of Southern England bound to suspended particulate material and dissolved in water

The spatial distribution of pharmaceuticals, personal care products (PPCPs) and other emerging contaminants (ECs) such as plasticisers, perflourinated compounds (PFCs) and illicit drug metabolites in water and bound to suspended particulate material (SPM) is not well-understood. Here, we quantify levels of thirteen selected contaminants in water (n=88) and their partition to suspended particulate material (SPM, n=16) in three previously-unstudied rivers of Greater London and Southern England during a key reproduction/spawning period. Analysis was conducted using an in-house validated method for Solid Phase Extraction followed by High-Performance Liquid Chromatography-Tandem Mass-Spectrometry. Analytes were extracted from SPM using an optimised method for ultrasonic-assisted solvent extraction. Detection frequencies of contaminants dissolved in water ranged from 3% (ethinylestradiol) to 100% (bisphenol-A). Overall mean concentrations in the aqueous-phase ranged from 14.7ng/L (benzoylecgonine) to 159ng/L (bisphenol-A). Sewage treatment works (STW) effluent was the predominant source of pharmaceuticals, while plasticisers/perfluorinated compounds may additionally enter rivers via other sources. In SPM, detection frequencies ranged from 44% (PFOA) to 94% (hydroxyacetophenone). Mean quantifiable levels of analytes bound to SPM ranged from 13.5ng/g dry SPM (0.33ng bound/L water) perfluorononanoic acid to 2830ng/g dry SPM (14.3ng bound/L water) perfluorooctanesulfonic acid. Long chain (>C7) amphipathic and acidic PFCs were found to more preferentially bind to SPM than short chain PFCs and other contaminants (Kd=34.1–75.5 vs <5 respectively). Per capita daily contributions of studied contaminants entering rivers ranged from 0.157μg/person/day of benzoylecgonine (cocaine metabolite) to 58.6μg/person/day of bisphenol-A. The large sample size of this work (n=104) enabled ANOVA followed by Tukey HSD post-hoc tests to establish significant trends in PPCP/EC spatial distribution from headwaters through downstream stretches of studied rivers. Novel findings include environmental Kd calculations, the occurrence of contaminants in river headwaters, increases in contaminant metabolite concentrations downstream of STW effluents revealing possible in-river degradation or de-conjugation, the influence of polarity and acidity in the partition of contaminants to particulate-material, among others.

Markers of anthropogenic contamination: A validated method for quantification of pharmaceuticals, illicit drug metabolites, perfluorinated compounds, and plasticisers in sewage treatment effluent and rain runoff

An effective, specific and accurate method is presented for the quantification of 13 markers of anthropogenic contaminants in water using solid phase extraction (SPE) followed by high performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). Validation was conducted according to the International Conference on Harmonisation (ICH) guidelines. Method recoveries ranged from 77 to 114% and limits of quantification between 0.75 and 4.91 ng/L. A study was undertaken to quantify the concentrations and loadings of the selected contaminants in 6 sewage treatment works (STW) effluent discharges as well as concentrations in 5 rain-driven street runoffs and field drainages. Detection frequencies in STW effluent ranged from 25% (ethinylestradiol) to 100% (benzoylecgonine, bisphenol-A (BPA), bisphenol-S (BPS) and diclofenac). Average concentrations of detected compounds in STW effluents ranged from 3.62 ng/L (ethinylestradiol) to 210 ng/L (BPA). Levels of perfluorinated compounds (PFCs) perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) as well as the plasticiser BPA were found in street runoff at maximum levels of 1160 ng/L, 647 ng/L and 2405 ng/L respectively (8.52, 3.09 and 2.7 times more concentrated than maximum levels in STW effluents respectively). Rain-driven street runoff may have an effect on levels of PFCs and plasticisers in receiving rivers and should be further investigated. Together, this method with the 13 selected contaminants enables the quantification of various markers of anthropogenic pollutants: inter alia pharmaceuticals, illicit drugs and their metabolites from humans and improper disposal of drugs, while the plasticisers and perfluorinated compounds may also indicate contamination from industrial and transport activity (street runoff).

Applying SWAT to predict ortho-phosphate loads and trophic status in four reservoirs in the upper Olifants catchment, South Africa

Abstract. Excessive phosphate loading in the upper Olifants River, South Africa has resulted in widespread eutrophication and associated ecosystem health impacts. The majority of sewage treatment works (STWs) are operating poorly and are likely an important source of bioavailable ortho-phosphate (OP) in the catchment. The Soil Water Assessment Tool (SWAT) was used to identify important sources of OP loading in the catchment and to predict changes in the trophic status of four reservoirs associated with three STW effluent OP standards (the current average of 4 mg L−1 and standards of 1 and 0.1 mg L−1). Nash–Sutcliffe and PBIAS statistics showed good model performance for simulations of flow and OP loading using a multi-site calibration and validation approach. Key sub-catchments responsible for high OP loading were identified. Three of the four reservoirs are heavily impacted by OP loading originating from STWs. Two reservoirs show mean annual OP concentrations indicative of eutrophic conditions and a 1 mg L−1 effluent standard would reduce concentrations to well within the mesotrophic range. There was little difference in OP loads and concentrations associated with the 1 and 0.1 mg L−1 effluent standards, indicating that attention to nonpoint sources would be required to realise any benefit associated with the strictest effluent standard. Regression analyses and associated 95% prediction limits between simulated OP loads and concentrations for all effluent treatment scenarios from 2002 to 2010 allowed for the quantification of OP loading that would ensure a specific trophic status in each reservoir. This study is one of the first to apply SWAT in simulating OP loading and concentrations in large reservoirs, and its application in South Africa provides further support for its utility throughout a wide geographical area.

Phosphorus and Emerging Micro-pollutants in Surface Waters: Challenges and Prospects for Water Quality Improvements

An oversupply of Phosphorus in water bodies accelerates growth of algae and higher forms of plant life to produce undesirable impacts on overall water quality. Phosphorus inputs to surface waters arise from a variety of point and nonpoint sources. However much of the P is contributed by agricultural runoff and outfall of treated (or untreated) wastewater in receiving water-bodies. Point sourced-P inputs to waters have considerably decreased in recent years, at least partly driven by regulatory requirements, e.g. the EU Water Framework Directive. This has largely been achieved by removing P from treated wastewaters at sewage treatment works (STWs). Studies have shown that introducing an additional treatment step (“P-stripping”) can significantly reduce P in STW outfalls. Given P deposits are depleting, there is much interest in phosphorus recovery from wastewaters. A few STWs have already started to recover P as struvite (NH4MgPO4.6H2O) mineral – a substitute for commercially produced P-fertilizers. This requires major investment and is not economically viable at small STWs. Nonetheless it is a major breakthrough in terms of P recovery and its use. Effluents from sewage treatment works (STW) can often contain a complex mixture of residual microcontaminants, not removed during wastewater treatment. Organic micro-pollutants have been found in rivers receiving STW effluents. Such residual contaminants have become the focus of an emerging field of water quality study and are collectively referred to as pharmaceuticals and other personal healthcare products, PPHCPs. Many of these chemicals have the ability to effect the hormonal signaling of organisms and are called endocrine disrupting compounds (EDC). Such chemicals have shown some of the most damaging biological effects in aquatic organisms. Biological effects in the aquatic environment are typically related to the development of intersex in fish. Recent research shows the use of STW practices such as upgrading from using a combined trickling filter contact process to activated sludge treatment, ozonation, membrane filtration and use of suspended biofilm reactors reduces the amount of EDCs in waste effluent. It is thus possible to remove contaminants from STW effluents, but it will not be possible without major infrastructure improvements. This paper presents the challenges and prospects of P and micro-organic pollutants in surface waters.

Fractionation of wastewater characteristics for modelling of Firle Sewage Treatment Works, Harare, Zimbabwe

Varying conditions are required for different species of microorganisms for the complex biological processes taking place within the activated sludge treatment system. It is against the requirement to manage this complex dynamic system that computer simulators were developed to aid in optimising activated sludge treatment processes. These computer simulators require calibration with quality data input that include wastewater fractionation among others. Thus, this research fractionated raw sewage, at Firle Sewage Treatment Works (STW), for calibration of the BioWin simulation model. Firle STW is a 3-stage activated sludge system. Wastewater characteristics of importance for activated sludge process design can be grouped into carbonaceous, nitrogenous and phosphorus compounds. Division of the substrates and compounds into their constituent fractions is called fractionation and is a valuable tool for process assessment. Fractionation can be carried out using bioassay methods or much simpler physico-chemical methods. The bioassay methods require considerable experience with experimental activated sludge systems and associated measurement techniques while the physico-chemical methods are straight forward. Plant raw wastewater fractionation was carried out through two 14-day campaign periods, the first being from 3 to 16 July 2013 and the second was from 1 to 14 October 2013. According to the Zimbabwean Environmental Management Act, and based on the sensitivity of its catchment, Firle STW effluent discharge regulatory standards in mg/L are COD (<60), TN (<10), ammonia (<0.2), and TP (<1). On the other hand Firle STW Unit 4 effluent quality results based on City of Harare records in mg/L during the period of study were COD (90±35), TN (9.0±3.0), ammonia (0.2±0.4) and TP (3.0±1.0). The raw sewage parameter concentrations measured during the study in mg/L and fractions for raw sewage respectively were as follows total COD (680±37), slowly biodegradable COD (456±23), (0.7), readily biodegradable COD (131±11), (0.2), soluble unbiodegradable COD (40±3), (0.06), particulate unbiodegradable COD (53±3) (0.08), total TKN (40±4) mg/L, ammonia (28±6), (0.68), organically bound nitrogen (12±2), (0.32), TP (15±1.4), orthophosphates (9.6±1.4), (0.64), and organically bound TP (5.4±1.4), (0.36), soluble unbiodegradable TP (0.4±0), (0.03), particulate unbiodegradable TP (0.05±0), (0.003). Thus, wastewater at Firle STW was found to be highly biodegradable suggesting optimisation of biological nutrient removal process will generally achieve effluent regulatory standards compliance. Thus, opportunities for plant optimisation do exist of which modelling with the use of a simulator is recommended to achieve recommended effluent standards in addition to reduction of operating costs.

Temporal variability in nutrient concentrations and loads in the River Tamar and its catchment (SW England) between 1974 and 2004

This study reports the results from the analyses of a 30-year (1974-2004) river water quality monitoring dataset for NO x -N (NO₃-N + NO2-N), NH₄-N, PO₄-P and SiO₂-Si at the tidal limit of the River Tamar (SW England), an agriculturally dominated and sparsely populated catchment. Annual mean concentrations of NH4-N, PO₄-P and SiO₂-Si were similar to other rural UK rivers, while annual mean concentrations of NO x -N were clearly lower. Estimated values for the 1940s were much lower than for those of post-1974, at least for NO₃-N and PO₄-P. Flow-weighted mean concentrations of PO₄-P decreased by approximately 60 % between 1974 and 2004, although this change cannot be unequivocally ascribed to either PO₄-P stripping from sewage treatment work effluents or reductions in phosphate fertiliser applications. Lower-resolution sampling (to once per month) in the late 1990s may also have led to the apparent decline; a similar trend was also seen for NH4-N. There were no temporal trends in the mean concentrations of NO x -N, emphasising the continuing difficulty in controlling diffuse pollution from agriculture. Concentrations of SiO₂-Si and NO x -N were significantly and positively correlated with river flows ≤15 m(3) s(-1), showing that diffuse inputs from the catchment were important, particularly during the wet winter periods. In contrast, concentrations of PO₄-P and NH4-N did not correlate across any flow window, despite the apparent importance of diffuse inputs for these constituents. This observation, coupled with the absence of a seasonal (monthly) cycle for these nutrients, indicates that, for PO₄-P and NH4-N, there were no dominant sources and/or both undergo extensive within-catchment processing. Analyses of nutrient fluxes reveal net losses for NO₃-N and SiO₂-Si during the non-winter months; for NO3-N, this may be due to denitrification. Areal fluxes of NO x -N from the catchment were towards the higher end of the range for the UK, while NH₄-N and PO₄-P were closer to the lower end of the ranges for these nutrients. These data, taken together with information on sestonic chlorophyll a, suggest that water quality in the lower River Tamar is satisfactory with respect to nutrients. Analyses of these monitoring data, which were collected at considerable logistical and monetary cost, have revealed unique insights into the environmental behaviour of key nutrients within the Tamar catchment over a 30-year period.

Elimination of estrogens and estrogenic activity from sewage treatment works effluents in subsurface and surface flow constructed wetlands

The effluents discharged from sewage treatment works (STWs) are major sources of environmental estrogens, which poses an urgent need to explore appropriate techniques for effluent-polishing. In light of the debate concerning the effectiveness of constructed wetlands (CW) for the elimination of estrogens, the present study evaluated and compared the performance of two basic types of CW, free water surface (FWS) and subsurface flow (SSF) systems. Two FWS and two SSF field CW mesocosms were fed continuously with an STW effluent. All the mesocosms provided an effective elimination of estrogens and estrogenic activity. Unexpectedly, the performance of FWS mesocosms was not inferior to that of SSF mesocosms. Additional shading experiments demonstrated that the presence of filamentous green algae along with the sunlight enhanced the removal of estrogens and estrogenic activity in FWS mesocosms, enabling FWS mesocosms to perform comparably to SSF mesocosms. Microbial inhibition tests further indicated that Spirogyra sp. itself rather than algae-attached bacteria played an important role in the removal of estrogen and estrogenic activity.

Colloids as a sink for certain pharmaceuticals in the aquatic environment

The occurrence and fate of pharmaceuticals in the aquatic environment is recognized as one of the emerging issues in environmental chemistry and as a matter of public concern. Existing data tend to focus on the concentrations of pharmaceuticals in the aqueous phase, with limited studies on their concentrations in particulate phase such as sediments. Furthermore, current water quality monitoring does not differentiate between soluble and colloidal phases in water samples, hindering our understanding of the bioavailability and bioaccumulation of pharmaceuticals in aquatic organisms. In this study, an investigation was conducted into the concentrations and phase association (soluble, colloidal, suspended particulate matter or SPM) of selected pharmaceuticals (propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac, and meclofenamic acid) in river water, effluents from sewage treatment works (STW), and groundwater in the UK. The occurrence and phase association of selected pharmaceuticals propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac, and meclofenamic acid in contrasting aquatic environments (river, sewage effluent, and groundwater) were studied. Colloids were isolated by cross-flow ultrafiltration (CFUF). Water samples were extracted by solid-phase extraction (SPE), while SPM was extracted by microwave. All sample extracts were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring. Five compounds propranolol, sulfamethoxazole, carbamazepine, indomethacine, and diclofenac were detected in all samples, with carbamazepine showing the highest concentrations in all phases. The highest concentrations of these compounds were detected in STW effluents, confirming STW as a key source of these compounds in the aquatic environments. The calculation of partition coefficients of pharmaceuticals between SPM and filtrate (observed partition coefficients, Kobsp, Kobsoc), between SPM and soluble phase (intrinsic partition coefficients, Kintp, Kintoc), and between colloids and soluble phase (Kcoc) showed that intrinsic partition coefficients (Kintp, Kintoc) are between 25% and 96%, and between 18% and 82% higher than relevant observed partition coefficients values, and are much less variable. Secondly, Kcoc values are 3-4 orders of magnitude greater than Kintoc values, indicating that aquatic colloids are substantially more powerful sorbents for accumulating pharmaceuticals than sediments. Furthermore, mass balance calculations of pharmaceutical concentrations demonstrate that between 23% and 70% of propranolol, 17-62% of sulfamethoxazole, 7-58% of carbamazepine, 19-84% of indomethacine, and 9-74% of diclofenac are present in the colloidal phase. The results provide direct evidence that sorption to colloids provides an important sink for the pharmaceuticals in the aquatic environment. Such strong pharmaceutical/colloid interactions may provide a long-term storage of pharmaceuticals, hence, increasing their persistence while reducing their bioavailability in the environment. Pharmaceutical compounds have been detected not only in the aqueous phase but also in suspended particles; it is important, therefore, to have a holistic approach in future environmental fate investigation of pharmaceuticals. For example, more research is needed to assess the storage and long-term record of pharmaceutical residues in aquatic sediments by which benthic organisms will be most affected. Aquatic colloids have been shown to account for the accumulation of major fractions of total pharmaceutical concentrations in the aquatic environment, demonstrating unequivocally the importance of aquatic colloids as a sink for such residues in the aquatic systems. As aquatic colloids are abundant, ubiquitous, and highly powerful sorbents, they are expected to influence the bioavailability and bioaccumulation of such chemicals by aquatic organisms. It is therefore critical for colloids to be incorporated into water quality models for prediction and risk assessment purposes.

A theoretical estimation of the concentration of steroid estrogens in effluents released from municipal sewage treatment plants into aquatic ecosystems of central-southern Chile

Endocrine disorders associated with sewage effluents have been documented in aquatic species from various regions of the world and sewage treatment works (STWs) are now widely recognized as one of the major discharge source of endocrine disrupting compounds. Steroid estrogens usually emerge as the main contributors to the endocrine disrupting capacity of municipal sewage effluents. Because human wastes are believed to be the primary source of release of steroid estrogens in watercourses, the presence of these compounds in aquatic systems is likely to constitute a pervasive ecological problem. In spite of that, the endocrine disrupting impact of sewage effluents has rarely been investigated in South America. In this paper, we used Johnson and Williams' predictive model to estimate the concentration of steroid estrogens in effluents released from 38 municipal STWs of central-southern Chile and to assess steroid estrogen concentrations in rivers. In STW effluents, we estimated the estrogen concentrations to range from 9.35 to 739.92 ng/L for estrone, 1.03 to 81.74 ng/L for estradiol and 0.38 to 30.56 ng/L for ethynylestradiol. Overall, the predicted estrogen concentrations are significantly higher than those reported for STW effluents in the literature. This can be explained by demographic and sewage flow differences between Chile and industrialized western countries. Predicted steroid estrogen concentrations at river sites indicate that endocrine disruption in fish is likely to occur in the Itata catchment. However, future research is needed to attest this and to evaluate the real impact of the STW discharges into central-southern Chile's marine and freshwater environments.

Environmental Health Impacts of Equine Estrogens Derived from Hormone Replacement Therapy

Many factors have been considered in evaluations of the risk-benefit balance of hormone replacement therapy (HRT), used for treating menopausal symptoms in women, but not its potential risks for the environment We investigated the possible environmental health implications of conjugated equine estrogens (CEEs), the most common components of HRT, including their discharge into the environment, their uptake, potency, and ability to induce biological effects in wildlife. Influents and effluents from four U.K. sewage treatment works (STWs), and bile of effluent-exposed fish, were screened for six equine estrogens. In vitro estrogen receptor (ER) activation assays were applied in humans and fish to compare their potencies, followed by in vivo exposures of fish to equine estrogens and evaluation of bioaccumulation, estrogenic responses, and ER gene expression. The equine estrogen equilenin (Eqn), and its metabolite 17beta-dihydroequilenin (17beta-Eqn), were detected by tandem GC-MSMS in all STW influent samples and 83% of STW effluent samples analyzed, respectively, at low concentrations (0.07-2.6 ng/L) and were taken-up into effluent-exposed fish. As occurs in humans, these estrogens bound to and activated the fish ERs, with potencies at ERalpha 2.4-3490% of thatfor 17beta-estradiol. Exposure of fish for 21 days to Eqn and 17beta-Eqn induced estrogenic responses including hepatic growth and vitellogenin production at concentrations as low as 0.6-4.2 ng/L. Associated with these effects were inductions of hepatic ERalpha and ERbeta1 gene expression, suggesting ER-mediated mechanism(s) of action. These data provide evidence for the discharge of equine estrogens from HRT into the aquatic environment and highlight a strong likelihood that these compounds contribute to feminization in exposed wildlife.

Exposure to Treated Sewage Effluent Disrupts Reproduction and Development in the Seasonally Breeding Ramshorn Snail (Subclass: Pulmonata, Planorbarius corneus)

Experiments were conducted to assess the impacts of exposure to sewage treatment works (STW) effluent upon the growth, reproductive function, and sexual development of the European mollusc, Planorbarius corneus under seasonally varying temperatures and photoperiodic conditions. In river water, a clear seasonal change in the number and weight of egg masses (during both 2003 and 2004), and in the number of eggs produced, was found, providing evidence for profound effects of both changing temperature and photoperiod on reproduction. Exposure to STW effluent caused disturbances in this seasonal reproductive cycle at all concentrations tested. The effects included significant dose-dependent increases in fecundity and in the overall length of the reproductive cycle in adult snails exposed to both 50% and 100% effluent relative to river water for a period of up to 14 weeks. Disturbances in the development of both the male and female gametes of the both the adult snails and their developmentally exposed offspring were also seen. These effects were more evident in the offspring than in the adults.

Oxidative damage in rainbow trout caged in a polluted river

Sewage treatment works (STWs) are a common source of chemicals entering into the aquatic environment. In order to assess effects of these effluents on oxidative stress parameters in aquatic organisms, we caged rainbow trout at five sites: upstream, near an STW effluent, and three sites downstream in the river Viskan in western Sweden for 14 days during autumn, 2006. We then measured protein carbonyls in plasma as well as 20S proteosome activity and lipid peroxidation products, i.e. MDA and 4-HNE, in liver samples. Levels of both lipid and protein oxidative damage products were elevated in fish caged near the STW effluent while 20S activity showed no differences. This argues that complex mixtures of chemicals entering into the aquatic environment do have deleterious effects on fish. Additionally, oxidative stress parameters can serve as a biomarker in aquatic organisms.

Proteomic analyses indicate induction of hepatic carbonyl reductase/20 β-hydroxysteroid dehydrogenase B in rainbow trout exposed to sewage effluent

Proteomic analyses were performed to identify regulated liver proteins in rainbow trout ( Oncorhynchus mykiss) caged upstream and downstream from a sewage treatment works (STW). Two-dimensional gel electrophoresis, image analysis and FT-ICR mass-spectrometry revealed four regulated protein spots. The three down-regulated spots contained betaine aldehyde dehydrogenase, lactate dehydrogenase and an unidentified protein respectively. The only up-regulated spot consisted of both mitochondrial ATP synthase alpha-subunit and carbonyl reductase/20 β-hydroxysteroid dehydrogenase (CR/20 β-HSD). Further studies using quantitative PCR revealed a 13.5-fold induction of CR/20 β-HSD B mRNA following STW effluent exposure. The CR/20 β-HSD B gene was not regulated by 17 α-ethinylestradiol, suggesting that its induction downstream from the STW is due to other factors than exposure to estrogens. Image analysis was initially performed on four gels from each group. These analyses suggested 15 regulated spots. However, validation of the 15 spots by increasing the number of replicates confirmed only four regulated spots. Hence, the present study also demonstrates the need for sufficient biological/technical replication in the interpretation of proteomic data.

The effects of sewage-treatment-works effluent on epilithic bacterial and algal communities of three streams in northern england

The responses of epilithic bacterial and algal communities to sewage-treatment-works (STW) effluent were studied in three streams in North Yorkshire, England, using both conventional microbiological techniques and the techniques of molecular genomics. Cod Beck, Thornton Beck and the River Wiske, were visited in May–June 2000 and January 2001 and the epilithic communities on submerged stones were sampled to determine chlorophyll-a, leucine assimilation, bacterial abundance, identity and abundance of microalgae, and epilithon dry and organic weights. Additionally, DNA from the epilithon of stones, collected in March–April and November 2000, was extracted, and samples were amplified using universal primers appropriate, respectively, for bacteria [Muyzer et al., 1993. Applied and Environmental Microbiology 59: 695–700] and microscopic phototrophs [Nubel et al., 1997. Applied and Environmental Microbiology 63: 3327–3332] followed by DGGE (Denaturing Gradient Gel Electrophoresis). Differences in algal community composition and abundance were greater between streams than between sites upstream and downstream of the STW outfalls. DGGE banding profiles of bacterial communities revealed grouping according to stream, and not the formation of communities characteristic of downstream sites; seasonal variation was also evident. Thus the discharge of STW effluent to the streams did not bring about the development of communities that are characteristically associated with organic pollution. Changes in composition and structure of bacterial and micro-algal epilithic communities were detected, but the relatively high quality effluents had only mild effects, not altering the environments sufficiently to override the natural differences between the three streams.

The water quality of the River Thame in the Thames Basin of south/south-eastern England

The water quality of the River Thame, a tributary of the River Thames in the Thames basin, is described in relation to point and diffuse contaminant inputs and runoff from permeable and impermeable bedrock geology with their own characteristic water quality. The data is examined to see if the market town of Aylesbury in the upper part of the catchment influences water quality. Previous studies highlighted the influence of Aylesbury sewage treatment works (STW) on soluble reactive phosphorus (SRP) concentrations in the river before and after phosphorus (P) stripping at the STW. Variations in water quality along the river are described and the study indicates that, apart from SRP, water quality determinants seem to be relatively unaffected by Aylesbury. The Thame water quality is compared with other catchment typologies and it is very similar to that of the main stem of the Thames even though the Thames is mainly Chalk groundwater fed. Differences in water quality largely link to the amount of STW effluent within the rivers and to the endmember compositions of the groundwater and near surface water sources.

Determination of Steroidal Hormone Profiles along the Jalle d'Eysines River (near Bordeaux, France)

Steroidal estrogens have been shown to be the main contributors to the estrogenic activity observed in aquatic systems contaminated with sewage treatment work effluents. Although the occurrence of steroid hormones in the environment has received a great deal of attention, little is known about their fate in aquatic systems. In the presentwork, concentrations of conjugated and unconjugated hormonal steroids (estrone, 17beta-estradiol, estriol, 17alpha-ethynylestradiol, mestranol, progesterone, norethindrone, and D-norgestrel) were determined in the effluent of the Eysines sewage treatment plant (near Bordeaux, France), and along the receiving river, the Jalle d'Eysines River. Sampling was undertaken in summer and in winter conditions, to study both the temporal and the spatial distributions of steroids in this river. Only unconjugated natural estrogens were detected in the effluent. Estrone was the dominant compound (detected in all effluent samples, 17.1-71.0 ng x L(-1)), while estradiol and its metabolite estriol were detected only once, at much lower levels (4.4 and 2.9 ng x L(-1), respectively). Levels of estrogens were clearly raised above the detection limits downstream of the Eysines STP effluent discharge. Seasonal variations of estrone degradation rates were observed. In summer, the apparent decay rates of estrogen levels exceeded that of dilution, indicating high removal rates from the water column: 50% of the initial amount of this steroid was degraded within 1.7 km downstream of the effluent discharge. In winter, however, estrone levels did not significantly decrease over a 10 km reach downstream of the effluent discharge (1.9-1.8 ng x L(-1)). Steroids were determined in the particulate material of the river, but levels were below the detection limits (0.4-1.9 ng x g(-1)), indicating that sorption was not a major sink of estrogens. Therefore, it is likely that biodegradation plays a major role in the removal of steroids from the river and the different decay rates are probably related to differences in bacterial activity within the river.

Water quality of treated sewage effluent in a rural area of the upper Thames Basin, southern England, and the impacts of such effluents on riverine phosphorus concentrations

Data for water quality surveys of effluent from sewage treatment works (STWs) in the rural Kennet/Dun sub-catchments of the upper Thames Basin are presented to characterize treated sewage effluent. Water quality determinand relationships with boron (B) are presented to provide information that can be used, with stream water quality information, to assess the relative inputs of treated sewage effluent pollutants to streams in rural areas. The approach is based on three points: (1) information on sewage effluent and agricultural pollution is of concern in relation to the management of UK lowland river systems in rural environments; (2) the lack of detailed information on sewage runoff chemistry and flow means that direct assessment of sewage effluent pollution to surface waters cannot be gauged; (3) B provides a clear chemically conservative marker of sewage sources in surface and ground waters. Three types of relationship to B were observed. Firstly, determinands such as Na, Cl, soluble reactive phosphorus (SRP) and NO 3 showed a positive linear relationship with B and there is a near zero intercept; these components are essentially derived from sewage sources. Secondly, Mg and SO 4 show linear relationships with B, but there is a non-zero intercept; these components have both a sewage component and a background component linked to water supplies from surface and groundwater sources. Thirdly, there are determinands that show no relationship with boron. In this study, an erratic pattern was observed for ammonium. This probably reflects the variable removal of this pollutant from sewage sources. Near constant concentrations of components such as Ca and alkalinity, which come from the background aquifer sources, were also found. SRP and B relationships for rivers in the upper Thames Basin showed the potential importance of (a) removal processes in the stream/groundwater for SRP derived from STW effluent inputs and (b) tertiary P stripping at the STWs on river water SRP levels. The importance of agricultural sources of SRP is questioned.

Investigating the environmental transport of human pharmaceuticals to streams in the United Kingdom

The occurrence of 12 selected pharmaceutical compounds and pharmaceutical compound metabolites in sewage treatment works (STW) effluents and surface waters was investigated. The substances selected for the monitoring programme were identified by a risk ranking procedure to identify those substances with the greatest potential to pose a risk to the aquatic environment. STW final effluent and surface water samples were collected from Corby, Great Billing, East Hyde, Harpenden and Ryemeads STWs. Ten of the 12 pharmaceutical compounds were detected in the STW effluent samples: propranolol (100%, median=76 ng/l), diclofenac (86%, median=424 ng/l), ibuprofen (84%, median=3086 ng/l), mefenamic acid (81%, median=133 ng/l), dextropropoxyphene (74%, median=195 ng/l), trimethoprim (65%, 70 ng/l), erythromycin (44%, <10 ng/l), acetyl-sulfamethoxazole (33%, median=<50 ng/l), sulfamethoxazole (9%, median=<50 ng/l), tamoxifen (4%, median=<10 ng/l). In the corresponding receiving streams, fewer compounds and lower concentrations were found: propranolol (87%, median=29 ng/l), ibuprofen (69%, median=826 ng/l), mefenamic acid (60%, median=62 ng/l), dextropropoxyphene (53%, median=58 ng/l), diclofenac (47%, median=<20 ng/l), erythromycin (38%, median=<10 ng/l), trimethoprim (38%, median=<10 ng/l), acetyl sulfamethoxazole (38%, median=<50 ng/l). Four human pharmaceutical compounds were detected in samples upstream of the STWs sampled: ibuprofen (57%, median=181 ng/l), trimethoprim (36%, median <10 ng/l), erythromycin (17%, median=<10 ng/l), propranolol (14%, median=<10 ng/l), suggesting that longer range stream transport of some compounds is possible. The particular STW that was sampled and the month that it was sampled significantly influenced the measured concentrations of several, but not all, substances. There was no significant relationship between usage data and the overall frequency with which different substances were detected. There was however, some evidence to suggest that usage data are positively associated with concentrations of pharmaceuticals in effluent and, particularly, with concentrations measured in surface waters below STWs. These results suggest that most sewage treatment works in England and Wales are likely to be routinely discharging small quantities of pharmaceuticals into UK rivers. None of the pharmaceuticals were found at concentrations that were high enough to cause acute toxic impacts to aquatic organisms. However, insufficient data were available to be able to comment on whether the concentrations measured have the potential to result in more subtle long-term effects on aquatic organisms (e.g. effects on growth, ability to reproduce).

Sediments are major sinks of steroidal estrogens in two United Kingdom rivers.

The occurrence of intersex fish in a number of European rivers has been attributed to exposure to estrogenic chemicals present in sewage treatment work (STW) effluents. To further understand the environmental fate of these contaminants, the estrogenic activity of effluents, water, and sediments were investigated both upstream and downstream of the major STW discharge in two United Kingdom rivers. Estrogenic activity, determined using the yeast estrogen-receptor transcription screen, of the major STW effluents on both rivers was similar, ranging from 1.4 to 2.9 ng 17beta-estradiol equivalents (EEQ)/L. Estrogenic activities of surface waters 1 km upstream and downstream of both STW inputs were less than the limits of detection (0.04 ng/L); however, levels of estrogenic activity in sediments were between 21.3 and 29.9 ng EEQ/kg and were similar at both upstream and downstream sites. Effluent and sediment extracts were fractionated by reverse phase-high-performance liquid chromatography, and estrogenic active fractions were further analyzed by gas chromatography-mass spectrometry. The major active chemicals in the two effluents and in the sediments were estrone with lesser amounts of 17beta-estradiol; however, at one site, a number of other unidentified estrogenic fractions were detected in the sediments. These results suggest that riverine sediments are a major sink and a potential source of persistent estrogenic contaminants.

Endocrine effects of environmental pollution on Xenopus laevis and Rana temporaria

To determine the capacity of sewage treatment work effluents to disrupt the endocrine system under semifield conditions, two amphibian species, Xenopus laevis and Rana temporaria, were exposed to the effluent of a regional sewage treatment plant in South Bavaria during larval development until completion of metamorphosis. Exposure was carried out in river water (Würm) as a reference, and a 1:12-mixture sewage effluent representing the real situation on the spot, and in a higher concentration of sewage using a 1:2 mixture. An accidental impact of industrial wastewater into the reference and dilution medium, Würm, which was caused by a spate in the respective area during the sensitive period of sex differentiation of amphibian larvae, is assumed to be responsible for the relatively high percentage of females observed by histological analysis in all treatment groups. All of these values were higher than those determined in controls exposed to artificial tap water in laboratory experiments conducted in a comparable study design. Sex ratios between species, revealed by the semifield study with decreasing portions of females from control to 1:12 to 1:2, were strongly correlated. Determination of biomarker-mRNA-levels in Xenopus liver using semiquantitative RT-PCR at the end of the experimental phase, when exposure regime has turned into the initially expected situation with the highest load of potential estrogens in the effluent, followed by 1:2 and 1:12 mixture, resulted in a significant increase of Vitellogenin-mRNA in female juveniles exposed to the highest portion of sewage, whereas expression of both androgen and estrogen receptor-mRNA showed no clear differences. The results concerning the induction of estrogenic biomarkers are in accordance with our findings for estrogen receptor binding of sample extracts from the Würm and sewage taken in parallel at the end of the experiment, when sewage extracts possessed a much higher ability to displace [ 3H]estradiol from the estrogen receptor than the ones extracted from the mixtures.