Urban Wastewater Discharges Research Articles

Effects of Sewage Discharge on Trophic State and Water Quality in a Coastal Ecosystem of the Gulf of California

This paper provides evidence of the effects of urban wastewater discharges on the trophic state and environmental quality of a coastal water body in a semiarid subtropical region in the Gulf of California. The concentrations of dissolved inorganic nutrients and organic matter from urban wastewater primary treatment were estimated. La Salada Cove was the receiving water body and parameters measured during an annual cycle were temperature, salinity, dissolved oxygen, nitrite, nitrate, ammonia, orthophosphate, and chlorophyll a. The effects of sewage inputs were determined by using Trophic State Index (TRIX) and the Arid Zone Coastal Water Quality Index (AZCI). It was observed that urban wastewater of the city of Guaymas provided 1,237 ton N yr−1 and 811 ton P yr−1 and TRIX indicated that the receiving water body showed symptoms of eutrophication from an oligotrophic state to a mesotrophic state; AZCI also indicated that the environmental quality of the water body was poor. The effects of urban wastewater supply with insufficient treatment resulted in symptoms of eutrophication and loss of ecological functions and services of the coastal ecosystem in La Salada Cove.

Radioactivity from Lisboa urban wastewater discharges in the Tejo River Estuary

Sediments, water, mussels and fish were collected monthly during a 19 month period at eight sampling stations along the North bank of the Tejo estuary (...

Evaluation of water quality in open channels flowing through Beni-Mellal City (Morocco) / Ocena jakości wody w otwartych kanałach płynących przez miasto Beni-Mellal (Maroko)

Abstract The water quality of the open channels (Foughal, OumDhar and Tamagnounte) flowing into Beni-Mellal city were assessed in a bid to determine impacts of anthropogenic activities. Physicochemical and bacteriological parameters comprising temperature, pH, alkalinity, electrical conductivity, oxidizability, total hardness, ammonia, nitrite, nitrate, total coliforms, fecal coliforms and geochemical analyses were determined for the channels water before reaching the irrigation areas. While biological parameters demonstrated substantial variability, other parameters showed relatively little spatial variations. The spatial variations in water quality may be attributed to the effects of the urban wastewater discharge in the channels and to surface urban and agricultural runoff. Compared with drinking water quality standards of Moroccan and WHO, the results indicated that the channels water was suitable for drinking purpose with prior treatment. Various determinants such as electrical conductivity, residual sodium carbonate, total dissolved solids and hardness revealed that all water samples were suitable for irrigation.

Spatial variations in the N2O emissions and denitrification potential of riparian buffer strips in a contaminated urban river

Spatial variations in the N2O emissions and denitrification potential of riparian buffer strips (RBS) in a polluted river were examined. The river received large pollutant inputs from urban runoff and wastewater discharge, resulting in impaired water quality in the river and downstream reservoir. The potential for nitrogen removal by RBS was evaluated by measuring in situ N2O emission fluxes in static closed chambers and sediment denitrification potentials with acetylene inhibition techniques. The results showed that N2O emission fluxes decreased from the upstream (16.39 μg/(m2·h)) to downstream (0.30 μg/(m2·h)) sites and from the water body to upland sites. The trend in decreasing N2O emission fluxes in the downstream direction was mainly associated with sediment/soil textures (clay loam→sandy soil) and sediment/soil water contents and was also related to the vegetation along the RBS and nutrients in the sediments/soils. The correlation coefficient was highest (r=0.769) between the N2O emission flux and sediment/soil water content. Sediment/soil denitrification potentials under N-amended and ambient conditions were higher (highest 32.86 mg/(kg·h)) for the upstream sites, which were consistent with in situ N2O flux rates.

Human health risk assessment of heavy metals via consumption of contaminated vegetables collected from different irrigation sources in Lahore, Pakistan

Soil pollution with heavy metals due to discharge of untreated urban and industrial wastewater is a major threat to ecological integrity and human well-being. The presenting study aimed to determine human health risks associated via food chain contamination of heavy metals routing from irrigation of urban and industrial wastewater. Irrigated water, soil and vegetables were analyzed for Cr2+, Co2+, Ni2+, Cu2+, Pb2+, Cd2+, Mn2+ and Zn2+; transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Cr2+, Pb2+ and Cd2+ in vegetables cultivated by wastewater exceeded the permissible limits (European Union, 2002) while TF was lower for all metals except Co2+ and HRI was found to be maximum for Spinacia oleracea (2.42mg/kg) and Brassica campestris (2.22mg/kg) cultivated by wastewater. S. oleracea, B. campestris, Coriandrum sativum posed a severe health risk with respect to Cd and Mn.

Processes and environmental quality in the Yangtze River system

The Yangtze River is a source of life and prosperity for China and the river basin is home to 400 million people, one third of the population of China. The river basin accounts for approximately 50 % of the national total runoff and 40 % of China’s freshwater resources, which makes the river basin the most important source for drinking water, supplying water to 186 cities. In addition, it is one of the major arteries of China’s inland water transportation. The fish fauna of the Yangtze catchment is one of the richest in the world, providing more than 70 % of the fishery production of China. Due to its rich natural resources, the river contributes a lot to China’s economic development. It serves as a key factor in inter-provincial commercial trade and the regional economy. The potential benefits even grew after the Three Gorges Dam began operating at full capacity after 2009, including flood control, energy production, and improved navigation. The river is also among the key locations for China’s agriculture and industry. In 2006, the river hosted 10,000 chemical enterprises—about half of the total number in China (cf., Floehr et al. 2013, this issue). However, the Yangtze River—as an ecosystem as well as a lifeline—is reported to have been drastically degraded during recent decades (Muller et al. 2008; Xie 2003). A recently published focus story in Science entitled “Trouble on the Yangtze” highlights the potentially serious consequences of proposed and completed hydropower dams on the Yangtze River for fish and cetaceans (Qiu 2012). As pointed out by Yang et al. (2012) in a reply to the above-mentioned article, water pollution is another important but largely ignored concern; rising contamination and hydrological changes in the Yangtze River accelerate the loss of local species. Discharge of industrial and urban wastewaters, along with the application of fertilizers, pesticides, and herbicides in farming, have negative impacts on the water quality (Muller et al. 2008; Yang et al. 2012; Jin et al. 2012). These impacts include release of heavy metals and persistent organic pollutants as PAHs, together with re-mobilization of polluted sediments. Due to its pollution, the Yangtze River was rated by the World Wildlife Fund as being amongst the top 10 rivers at risk in the world (Wong et al. 2007; Wang et al. 2012a). This special issue of Environmental Science and Pollution Research highlights selected papers presented at two International Workshops on “Processes in the Yangtze River System—Experiences and Perspectives, one held at RWTH Aachen University, Germany in 2011, and the other at Tongji University in Shanghai, China in 2012. Both workshops were held for the purpose of scientific exchange on recent cuttingedge environmental research in the Yangtze River with a focus on the Three Gorges Reservoir (TGR). The second of these conferences, which is summarized in a conference report by Holbach et al. (2012a), marked two important milestones in Sino–German cooperation: (a) the 10-year anniversary of successful scientific Sino–German cooperation on questions related to the newly built Three Gorges Dam and (b) the midpoint of the Yangtze-Hydro Project (Bergmann et al. 2012) funded by the German Federal Ministry of Education and Research from 2010 to 2014. In detail, more than a dozen papers on processes and environmental quality in the Yangtze River basin are presented in this special issue elucidating the following topics:

Vertical distribution profiles and diagenetic fate of synthetic surfactants in marine and freshwater sediments

This manuscript deals with the presence and degradation of the most commonly-used surfactants, including anionic (linear alkylbenzene sulfonates, LAS, and alkyl ethoxysulfates, AES) and non-ionic (alcohol polyethoxylates, AEOs, and nonylphenol polyethoxylates, NPEOs) compounds, in sediments and pore water from several aquatic environments (Southwest, Spain). Different vertical distributions were observed according to the respective sources, uses, production volumes and physicochemical properties of each surfactant. Levels of nonionics (up to 10mgkg−1) were twice as high as anionics in industrial areas and harbors, whereas the opposite was found near urban wastewater discharge outlets. Sulfophenyl carboxylic acids (SPCs), LAS degradation products, were identified at anoxic depths at some sampling stations. Their presence was related to in situ anaerobic degradation of LAS in marine sediments, whereas the occurrence of these metabolites in freshwater sediments was attributed to the existence of wastewater sources nearby. No significant changes in the average length of AEO and NPEO ethoxylated chains were observed along the sediment cores, suggesting that their biodegradation was very limited in the sampling area. This may be directly related to their lower bioavailability, as their calculated sediment–pore water distribution coefficients (log Ksw), which showed that non-ionic surfactants examined in this study had greater sorption affinity than the anionic surfactants (e.g., 2.3±0.3 for NPEOs).

Heavy metals pollution origin in the bed sediments of Aswan high dam reservoir: lithogenic or anthropogenic sources

Heavy metals are present in aquatic sediments as a result of chemical leaching of bed rocks (Lithogenic source), and discharge of urban and industrial wastewaters (Anthropogenic sources). It is important to provide information about the source of heavy metals pollution because high levels of heavy metals can often be attributed to anthropogenic influences, rather than natural enrichment of the sediment by geological weathering (Lithogenic influences). This study was initiated with the objective of determining the origin of heavy metals pollutants in the bed sediments of Aswan High Dam Reservoir (AHD) and to evaluates their environmental risk in reservoir water and its potential use (benefits and risks) in agricultural land. Total metals concentration, the element Enrichment Factor (EF) and the sequential extractions of heavy metals (speciation) were determined in addition to pH, organic matter content and grain size distribution. The results indicated that the total metal contents varied in the following ranges (in mg/kg): Al (1165-18000), Cd (0.62-2.17), Co (11-47), Cr (12-63), Cu (80-261), Fe (3027-36651), Mn (93-1908), Ni (11-58), Pb (7-29) and Zn (98-208). The enrichment factor for all metals in sediment was found to be low and the heavy metals speciation revealed that the exchangeable and carbonate bound fractions are entirely insignificant. The results revealed no anthropogenic contribution of heavy metals and the chemical weathering is a primary factor that controls the concentrations of metals in the bed sediments of the Reservoir. The results indicated that metals in the bed sediments of the reservoir did not represent environmental pollution risk and are derived from lithogenic (natural) processes (i.e weathering and soil formation). The bed sediments of the reservoir were found in the alkaline range and are promoting heavy metals precipitation. Thus it was recommended to use these sediments in soil amendment.

Analysis of seasonal variations in the quality of water in a reservoir using GIS techniques

This paper analyzes the seasonal behavior of water quality in the reservoir of Rio Hondo (Sali-Dulce river basin, Argentina) using Geographic Information Systems (GIS) interpolation techniques. Due to its geographical location, the water of this lake is influenced by human activities from the upper basin, such as agricultural development, urban and industrial wastewater discharges which vary in intensity depending on the season. In this study the techniques of interpolation IDW (Inverse Distance Weight) and Kriging were applied to values of a water quality index named ICA2. The integrated tool Geostatistics Analyst in ArcGIS 9.2 software was used to check if it is possible to get a proper ICA2 spatial interpolation with the employed methods and which of them would be the best technique to estimate the quality of water. With the observed and interpolated values of ICA2 index, a series of maps were obtained that allow us to conclude that both methods are valid for estimating trends in water quality. However, slightly better results have been obtained with the Kriging method.

CH4 Concentrations and Emissions from Three Rivers in the Chaohu Lake Watershed in Southeast China

This study was conducted at three rivers of the Chaohu Lake watershed during the summer season of 2008, aiming to investigate the diurnal variations of dissolved CH4 concentrations and emissions, as well as the dynamics of CH4 accumulation emission rates over consecutive 72 h. The results showed that CH4 concentrations in the Fengle, Hangbu, and Nanfei rivers ranged from 56.33–124.79, 160.82–341.03, and 213.49–716.81 nmol L−1, respectively, over a daily cycle; while the saturation of CH4 ranged from 188.72–418.07, 538.74–1 142.46, and 715.23–2 401.38%, respectively, which indicated that surface waters were in all cases oversaturated with respect to the atmosphere. An obvious diurnal variation pattern of the dissolved CH4 concentrations demonstrated a higher value during daytime but a lower value for night time. Additionally, the highest dissolved CH4 concentrations were detected in the Nanfei River which received substantial urban wastewater discharges. CH4 emissions measured with floating chambers ranged from 5.82–15.46, 5.77–8.41, and 13.51–49.25 mg C m−2 h−1 for the Fengle, Hangbu, and Nanfei rivers, respectively, over a daily cycle. Significantly higher CH4 emissions were also observed from the Nanfei River. The accumulative CH4 emissions for each river increased with time, while a decline trend on the accumulation rates was investigated over the consecutive 72 h.

Spatial and temporal changes in macrobenthic communities in the Amazon coastal zone (Guajará Estuary, Brazil) caused by discharge of urban effluents

Spatial and temporal changes in the structure of soft-bottom macrobenthic communities caused by discharges of urban wastewater were studied in the Guajara Estuary, Amazon coastal zone, Brazil. Samples were taken during the dry and rainy seasons at five sites close to wastewater sources (impacted) and two sites further away from effluent discharges (non-impacted). Samples were collected using a Petersen grab (20×20×20 cm) and passed through a 0.3 mm mesh screen. At each site, several parameters were determined in order to characterize the water (pH, QOD and NH 4 ) and sediment (mean grain size diameter, %OM and heavy metals). The benthic fauna was composed of 22 taxa dominated by polychaetes and oligochaetes. The data indicate that environmental contamination has not resulted in a highly polluted environment with a significant reduction in fauna. It would seem that the river flow and intense hydrodynamics dilute and minimize the effects of contaminants in the estuary. The main effect of the discharge effluents was a favorable organic enrichment. The fauna at the impacted sites was generally more diverse than at the non-impacted sites, dominated by Oligochaeta Tubificinae, and showed greater spatial heterogeneity.

Türkiye su politikalarının biyoetik değerlendirilmesi: Ergene Nehri örneği

In Turkey, the Ergene Basin comprising the Ergene River, is one of the river basins that has water pollution issues and extremely polluted due to the industrial and urban waste water discharges. The Ergene River is chosen as the subject of this study due to its pollution and Turkish water policies is evaluated bioethically over the example of Ergene River in accordance with the management policies in the basin. In this study, ecocentric and anthropocentric bioethical approaches to water policies constituted for the solution of water pollution issues are also discussed. This case study shows that in our country implemented water policies are inadequate with respect to bioethical view and there is anthropocentric approach instead of ecocentric approach. With this study, it is aimed to highlight the importance of ecocentric inquiry on water management policies of our country and to contribute in the creation of biopolitics formed with perception of bioethical value.

Measurement and simulation of dissolved oxygen in Zayandehrood river

Aims: This study aims to simulate dissolved oxygen of Zayandehrood river from regulating dam to Polle-Kalleh bridge using MIKE11 software that is a hydrodynamics and water quality model. Materials and Methods: During 5 months the samples were taken from four hydrometric stations and water quality parameters such as dissolved oxygen, pH, BOD (1 day, 3 days, 5 days, and 7 days), NH 4 , NO 3 - phosphate (PO4 3- ), and temperature were measured. Morphological and hydrological data were provided and introduced into the model. The model was calibrated and its accuracy was investigated. Results: The results indicated that concentration of PO4 3- , BOD5 , COD, NH 4 , and NO3 - exceeded surface water standards from regulating dam to Pole-Kalleh bridge. The results of the prediction for the next 25 years indicated that due to growth of population and industries along the river, concentration of some pollutants will be increased. Conclusions: The results indicated that although the current DO level is suitable for aquatic environment, this is not adequate for fish reproduction and migration. Prediction of the river water quality parameters for the future conditions showed that discharge of urban and rural wastewater to river should be avoided. In situations where release of effluent into the river is inevitable, nitrification process should be added to wastewater treatment processes.

Applicability of ecological assessment tools for management decision-making: A case study from the Lima estuary (NW Portugal)

The Water Framework Directive (WFD) aims to achieve and conserve a good ecological status of all surface waters, including estuarine environments, which should be assessed considering several biological elements, together with physical, chemical and pollution elements.In this study, we investigated the applicability of ecological indicators for a practical management issue: selection of the most suitable location for a marina in a salt-marsh temperate estuary (River Lima, NW Portugal). Considering the WFD principles, we assumed that the most suitable location for the implementation of a marina should be the one with the least ecological value, considering that it could be an opportunity for ecological rehabilitation. In order to attain this purpose, the ecological quality status of five potential locations in the navigable lower stretch of the Lima estuary was assessed following an ecosystem-based approach. Several key ecological quality elements such as physical and chemical parameters of water and sediment, phytoplankton biomass, as well as macroinvertebrate and fish communities were surveyed. In addition, heavy-metal analyses, fecal indicator evaluation and “first-screening” toxicity tests were also performed. All collected information was integrated using a scaled value approach, in order to rank the five locations. Furthermore, for the assessment of the ecological quality status of the potential sites, a macroinvertebrate (M-AMBI) and a demersal community based (EDI-Estuarine Demersal Indicators) indices were used. Different human pressures were detected, being the uppermost site more susceptible to urban wastewater discharge, whereas the location downstream the commercial seaport was more prone to accumulate contaminants in the sediments. The scaled values approach allowed the ranking of the potential sites, where the uppermost location ranked last. M-AMBI and EDI also classified that location with the lower ecological quality status. Both biological indices were in agreement concerning the discrimination of the location with the lowest ecological quality status, which coincided with the one ranked last by the scaled values approach. The selected biological indices proved to be useful tools for decision-making support in an environmental management context.

Monitoring and flux determination of trace metals in rivers of the Seversky Donets basin (Ukraine) using DGT passive samplers

This paper reports the results of the in situ application of diffusive gradients in thin-films (DGT) passive samplers for trace metals (Cd, Co, Cr, Cu, Ni, Pb and Zn) monitoring in transboundary Udy and Lopan rivers of the Seversky Donets watershed in the Kharkiv region (Ukraine), which has a long history of industrial development. The research discusses potential sources of DGT-measured labile metals in water and seasonal variations. Our results demonstrate the application of DGT for identifying and measuring labile metal concentrations in contrasted climate conditions (cold snowy winter and hot summer) and appropriateness of such a tool for continuous water monitoring with the presence of an ice cover. Results show that DGT-measured concentrations of most of trace metals were much higher downstream of the wastewater treatment plants discharges than upstream; thus wastewater treatment plants seemed not able to reduce or to remove trace metals’ contaminations and become major sources of pollutants in the studied rivers. The calculation of the average metal fluxes based on the DGT-measured concentrations confirmed that the urban wastewater discharges significantly contribute to the metal fluxes into the Udy and the Lopan rivers during both low-flow and high-flow periods. Compared to the wastewaters inputs to the rivers, the transboundary effect is limited, but should be taken into account as the origin of some metals is from sources located on the adjacent Russian territory.

Automatic Searching and Evaluation of Priority and Emerging Contaminants in Wastewater and River Water by Stir Bar Sorptive Extraction followed by Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry

A new analytical method based on stir bar sorptive extraction (SBSE), followed by comprehensive two-dimensional gas chromatography (GCxGC-TOF-MS), has been developed for the automatic searching and evaluation of nonpolar or semipolar contaminants in wastewater and river water. The target compounds selected were 13 personal care products (PCPs), 15 polycyclic aromatic hydrocarbons (PAHs) and 27 pesticides. Excellent results have been obtained in terms of separation efficiency and also in terms of compound identification. Exceptional method detection limits were achieved applying the optimized method, at or below 1 ng/L for most of the compounds in real samples. The reliable confirmation of analyte identity was possible at this low concentration level, even for typically troublesome compounds such as the PAHs. The other validation parameters were good. In addition to obtaining analytical information such as identification and quantification of target analytes, it is also possible to screen for nontarget compounds or unknowns. New contaminants have been identified in the wastewater effluents and river water samples, such as cholesterol and its degradation products, pharmaceuticals, industrial products, other pesticides, and PCPs. The multidimensional information generated by the instrument can also be used by the researchers for contrasting samples and identifying, much more easily, the major differences between samples. We have used this feature to propose studies of comparison between the fingerprinting of different water samples, such as the contamination variation along a river affected by the discharge of urban wastewaters and also the contamination variation over a period of time in the effluent. Results show that the most frequently detected contaminants (and the contaminants detected at higher concentrations) were the PCPs. The musk fragrances galaxolide and tonalid were the most concentrated compounds in the samples. The pesticides and PAHs were present at much lower concentration than PCPs.

Cleaning Up after the Log Drivers’ Waltz : Finding the Ottawa River Watershed

The Ottawa River has experienced the environmental impact of a succession of industrial uses from the lumber trade through hydroelectric power development to pulp and paper manufacturing. Each of these activities, and the introduction of substantial discharges of urban wastewater, has been the subject of legal intervention and regulatory controls. The present paper surveys this largely sectoral approach to water quality protection along the Ottawa River and notes in conclusion tentative steps being taken to formulate a more comprehensive and coherent framework on a watershed basis.

Fecal Pollution in Coastal Marine Sediments from a Semi-Enclosed Deep Embayment Subjected to Anthropogenic Activities: An Issue to Be Considered in Environmental Quality Management Frameworks Development

Sewage discharge is a major source of pollution in marine environments. Urban wastewaters can directly enter marine environments carrying pathogen organisms, organic loads, and nutrients. Because marine sediments can act as the ultimate fate of a wide range of pollutants, environmental quality assessment in this compartment can help to identify pollution problems in coastal areas. In the present study, characterization of surficial marine sediments allowed assessment of fecal pollution in a semi-enclosed deep embayment that is subjected to anthropogenic activities. Physicochemical parameters and fecal indicators presented a great spatial heterogeneity. Fecal coliform and Clostridium perfringens showed accumulation in an extensive area, not only in proximity to sewage discharge points, but also in sediments at 100 meters depth. Results included herein demonstrated that, in coastal areas, urban wastewater discharge can affect the whole ecosystem through accumulation of fecal matter in bottom sediments. Application of multivariate techniques provided useful information with applicability for management of coastal areas in such complex systems. Environmental implications of wastewater discharge in coastal areas indicate the need to implement and include sediment quality control strategies in legislative frameworks.

Modeling and evaluation of compliance to water quality regulations in bathing areas on the Daoulas catchment and estuary (France)

The microbiological quality of waters in estuaries determines their acceptability for recreational uses. Microbiological contamination often results from urban wastewater discharges or non-point source pollution (manure spreading), and can cause bathing zones to be closed. European regulations (EC/7/2006) have proposed standards (500 E. coli/100 ml) for the acceptability areas for bathing. In this study, two models were associated to simulate contamination: SWAT on a catchment and MARS 2D in the downstream estuary. After river flow calibration and validation, two scenarios were simulated in SWAT, and E. coli fluxes obtained at the main outlet of the catchment were then introduced into MARS 2D to follow E. coli concentrations in the estuary. An annual evaluation of compliance to bathing area water quality standards was then calculated, linked with daily rainfall classes. Water quality in the estuary was below the standard on 13 days, including 5 days with rainfall superior to 10 mm, due to faecal contamination from soil leaching by rain, and 5 days with rainfall ranging from 0.1 to 5 mm/day, due to the high frequency of this level of rainfall. To conclude, this study allowed us to demonstrate the efficiency of models to gain a better understanding on water quality degradation factors.

Impact of Urban Wastewater Discharges on the Sediments of a Small Mediterranean River and Associated Coastal Environment: Assessment of Estrogenic and Dioxin-like Activities

The Mediterranean region includes many small coastal rivers about which little is known concerning organic contaminant loads in their sediment. This study was designed to assess organic contamination in one of these small coastal rivers (Lez River) and associated coastal sediments. Levels of alkylphenols (APs), polycylic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were measured in sediments of the Lez River and two coastal lagoons impacted by wastewater discharges. In parallel, sediment surrounding a recently built submarine outfall that discharges treated wastewater, from an area encompassing some 450,000 inhabitants, into the sea was monitored a year after the beginning of emission via the outfall. Finally, these sediments were characterized by screening estrogenic, PAH-like and dioxin-like activities using in vitro bioassays. Both chemical analyses and bioassays revealed that wastewater inputs were a source of organic contamination of sediments from the Lez and lagoons, which still persisted 2 years after the discharges were stopped. APs could explain a small proportion of the overall estrogenic activities (up to 31%), suggesting that other estrogenic compounds were also present in the sediments. PAHs explained a great share (83% on average) of the EROD induction potency of the extracts. This survey should be the first step in the long-term monitoring of these sites.