Distribution and fate of metals in the dispersion plume of a major municipal effluent

The environmental impacts of municipal wastewater discharges on receiving waters are numerous and inputs of contaminants such as metals can cause toxicity to organisms in receiving waters. The effluents generated by the treatment plant of the city of Montreal, Canada, the largest such facility in the St. Lawrence Valley, was investigated to determine the environmental fate of trace metals in the receiving waters. Total and extractable metal concentrations were determined and physico-chemical parameters were measured to characterize the receiving waters and evaluate their influence on the fate and behaviour of metals released from the urban effluent. Our results showed that particulate metals near the effluent discharge point are highly reactive and their distribution seems to be significantly influenced by the abundance of HCl-reactive iron and manganese, which act as trace-metal carriers. The partitioning of metals between dissolved and particulate phases varies along the effluent dispersion plume and therefore could strongly influence the exposure routes for aquatic organisms that are exposed to the various contaminants released from the effluent.     

万家寨引黄北干线桑干河道输水水质模拟与控制

主要对采用河道输水方案的山西万家寨引黄北干线桑干河道水质进行模拟与控制研究,依据各水体特性建立河流水质数值模型和水库数值模型,运用系统分解方法将整个研究河道分解为若干个河段,并采用情景分析方法生成3个水质模拟情景,分析模拟结果表明,在山阴取水口和怀仁取水口水质达地表水Ⅲ类标准条件下,册田水库的入水水质不达标。应用反演思想生成2个水质控制情景和3个子情景,在水库出水口水质达标的情况下,分析确定沿河各排污口的污染物排放控制量,给出了保证册田水库水质安全的控制方法。     

Multivariate analysis of Almendares River waters.

The Almendares River is the most important surface water body of the Cuban capital, Havana. In the present work, the environmental quality of waters was studied as a function of the following 14 variables: content of calcium, cadmium, iron, potassium, magnesium, manganese, sodium, nickel, zinc, chlorine, bicarbonate, and sulfate; pH; and electric conductivity parameters, which were reduced to three new variables by means of principal component analysis (PCA). The content of metal increased in waters sampled at stations located near garbage dumps and decreased inside the Ejercito Rebelde dam. The variation of the river water environmental quality with rainy and dry seasons and the differentiation of samples in three groups along the river course were obtained by PCA and corroborated by discriminant analysis. Applied statistical techniques showed their ability for environmental interpretation of limited experimental data.     

湍流扩散方程数学解析的探讨

本文讨论了水流场中平流、分子扩散、湍流扩散、离散作用所引起的扩散物质质量通量的数学解析以及几种水质数学模型的应用条件。     

Identification of relevant micropollutants in Austrian municipal wastewater and their behaviour during wastewater treatment

The European Union has defined environmental quality standards (EQSs) for surface waters for priority substances and several other pollutants. Furthermore national EQSs for several chemicals are valid in Austria. The study investigated the occurrence of these compounds in municipal wastewater treatment plant (WWTP) effluents. In a first screening of 15 WWTPs relevant substances were identified, which subsequently were monitored in 9 WWTPs over 1 year (every 2 months). Out of 77 substances or groups of substances (including more than 90 substances) 13 were identified as potentially relevant in respect to water pollution and subjected to the monitoring, whereas most other compounds were detected in concentrations far below the respective EQS for surface waters and therefore not further considered. The preselected 13 compounds for monitoring were cadmium (Cd), nickel (Ni), copper (Cu), selenium (Se), zinc (Zn), diuron, polybrominated diphenyl ethers (PBDEs), di(ethyl-hydroxyl)phthalate (DEHP), tributyltin compounds (TBT), nonylphenoles (NP), adsorbable organic halogens (AOX) and the complexing agents ethylenediaminetetraacetic acid (EDTA) as well as nitrilotriacetic acid (NTA). In the effluents of WWTPs the concentrations of the priority substances Cd, NP, TBT and diuron frequently exceeded the respective EQS, whereas the concentrations for DEHP and Ni were below the respective EQS. The effluent concentrations for AOX, EDTA, NTA, Cu, Se and Zn frequently are in the range or above the Austrian EQS for surface waters. Besides diuron and EDTA all compounds are removed at least partially during wastewater treatment and for most substances the removal via the excess sludge is the major removal pathway. For the 13 compounds which were monitored in WWTP effluents population equivalent specific discharges were calculated. Since for many compounds no or only few information is available, these population equivalent specific discharges can be used to assess emissions from municipal WWTPs to surface waters as well as to make a first assessment of the impact of a discharge on surface waters chemical status. Comparing discharges and river pollution on a load basis, the influence of diffuse sources becomes obvious and therefore should also be taken into consideration in river management.     

Partitioning and availability of sediment-bound metals following final sewage effluent release to a lowland river

A simple partitioning scheme was used to assess the partitioning and behaviour of copper, cadmium, iron, lead and manganese within the surface waters and sediments of the River Yare, Norfolk, UK, following the discharge of final effluent to the water course from municipal sewage treatment works (STW). Sewage effluent discharges were shown to increase metal concentrations and complexation capacities in receiving waters, but the tidal nature of the river meant that surface water monitoring could not accurately pinpoint the contamination source or the main metal partitioning trends. Sediments formed a more stable base on which to perform contaminant studies: these revealed that metals discharged from the STW rapidly accumulated in bottom deposits in relative stable chemical forms.     

Biotransformation rates of the butoxyethyl ester of 2,4-D by bottom and surface aufwuchs

An experiment was conducted to investigate the variability in biotransformation rate coefficients of a xenobiotic, the butoxyethyl ester of 2,4- , in natural waters between aufwuchs grown on Teflon strips located on the bottom and at the water surface of a pond and a river. The colonized strips and the natural waters were transported to the laboratory where the biotransformation studies were done under controlled conditions. Statistical analyses applied to the first-order rate coefficients showed a significant difference between bottom and surface aufwuchs for the river only. For both pond and river, a significant difference was shown when the aufwuchs was suspended, however. The aufwuchs mat thickness was significantly different between bottom and surface for the pond but not for the river and the biomass as ash-free dry weight was significantly different for both water bodies. The variability of biomass and first-order rate coefficients was higher with the bottom colonized aufwuchs than with the surface colonized aufwuchs.     

Perfluorinated Surfactants in Surface and Drinking Waters (9 pp)

Background, Aim and Scope In this paper recent results are provided of an investigation on the discovery of 12 perfluorinated surfactants (PS) in different surface and drinking waters (Skutlarek et al. 2006 a, Skutlarek et al. 2006 b). In the last years, many studies have reported ubiquitous distribution of this group of perfluorinated chemicals, especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in the environment, particularly in wildlife animal and human samples (Giesy and Kannan 2001, Houde et al. 2006, Prevedouros et al. 2006). Perfluorinated surfactants (e.g. PFOS and PFOA) have shown different potentials for reproductory interference and carcinogenity in animal experiments as well as partly long half-lives in humans (Guruge et al. 2006, FSA UK 2006a, FSA UK 2006b, 3M 2005, OECD 2002, Yao and Zhong 2005). They possess compound-dependent extreme recalcitrance against microbiological and chemical degradation and, in addition, they show variable potentials for bioaccumulation in animals and humans (Houde et al. 2006). Materials and Methods: Surface and drinking water samples were collected from different sampling sites: - Surface waters: samples taken from the rivers Rhine, Ruhr, Moehne and some of their tributaries. Further samples were taken from the Rhine-Herne-Canal and the Wesel-Datteln-Canal. - Drinking waters: samples taken in public buildings of the Rhine-Ruhr area. After sample clean-up and concentration by solid-phase extraction, the perfluorinated surfactants were determined using HPLC-MS/MS. Results: All measured concentrations (sum of seven mainly detected components) in the Rhine river and its main tributaries (mouths) were determined below 100 ng/L. The Ruhr river (tributary of the Rhine) showed the highest concentration (94 ng/L), but with a completely different pattern of components (PFOA as major component), as compared with the other tributaries and the Rhine river. Further investigations along the Ruhr river showed remarkably high concentrations of PS in the upper reaches of the Ruhr river and the Moehne river (tributary of the Ruhr) (Ruhr: up to 446 ng/L, Moehne: up to 4385 ng/L). The maximum concentration of all drinking water samples taken in the Rhine-Ruhr area was determined at 598 ng/L with the major component PFOA (519 ng/L). Discussion: The surface water contaminations most likely stem from contaminated inorganic and organic waste materials (so-called 'Abfallgemisch'). This waste material was legally applied to several agricultural areas on the upper reaches of the Moehne. Perfluorinated surfactants could be detected in some suchlike soil samples. They contaminated the river and the reservoir belonging to it, likely by superficial run-off over several months or probably years. Downstream, dilution effects are held responsible for decreasing concentrations of PS in surface waters of the Moehne and the Ruhr river. In analogy to the surface water samples, PS (major component PFOA) can be determined in many drinking water samples of the Rhine-Ruhr area where the water supplies are mainly based on bank filtration and artificial recharge. Conclusions: The concentrations found in drinking waters decreased with the concentrations of the corresponding raw water samples along the flow direction of the Ruhr river (from east to west) and were not significantly different from surface water concentrations. This indicates that perfluorinated surfactants are at present not successfully removed by water treatment steps. Recommendations and Perspectives: Because of their different problematic properties (persistence, mobility, toxicity, bioaccumulation), the concentrations of specific perfluorinated surfactants and their precursors in drinking waters and food have to be minimised. Therefore, it is of utmost importance to take the initiative to establish suitable legal regulations (limitations/ban) concerning the production and use of these surfactants and their precursors. Furthermore, it is indispensable to protect water resources from these compounds. A discussion on appropriate limit values in drinking water and foodstuffs is urgently needed. Concerning the assumed soil contamination, the corresponding regulation (Bioabfall-Verordnung 1998 – Regulation on Organic Waste 1998) should be extended to allow the control of relevant organic pollutants.     

A field study of triclosan loss rates in river water (Cibolo Creek, TX)

Triclosan (TCS) is an anti-microbial agent used in down-the-drain consumer products. Following sewage treatment some of the triclosan will enter receiving waters. This study was designed to determine the die-away rate of triclosan released into a river as part of the sewage treatment plant effluent matrix. The study was conducted in Cibolo Creek, a moderate sized stream (discharge approximately 0.1 m(3)s(-1)) located in South Central Texas. Triclosan was analyzed from samples collected upstream of the sewage treatment plant, the sewage treatment plant effluent, and the river downstream from the effluent discharge. The first-order loss rate of parent triclosan from the water column was calculated from measured data (0.06 h(-1)) and this rate corresponded to a 76% reduction in triclosan over an 8 km river reach below the discharge. Mathematical modeling indicated that sorption and settling accounted for approximately 19% of total triclosan loss over 8 km. When removing sorption and settling, the remaining amount of triclosan had an estimated first-order loss rate of 0.25 h(-1). This loss rate was presumably due to other processes such as biodegradation and photolysis. These data show that loss of parent triclosan from the water column is rapid. Additional data are needed to fully document loss mechanisms.     

Mercury assessment and evaluation of its impact on fish in the Cecina river basin (Tuscany, Italy)

This paper reports the results of mercury contamination monitoring in the Cecina river basin (Tuscany, Italy). Mercury was measured in the waters, sediments and fish species of the river and its most important tributaries. In fish specimens the organic form was also determined. The results showed high mercury levels in most of the samples analysed. Particularly high concentrations were found in the sediments of the S. Marta canal flowing into the Cecina, where a chlor-alkali plant discharges its wastes, and high levels were still detectable 31 km downstream from the confluence. Near the S. Marta confluence many fish specimens were very contaminated and a study on Leuciscus cephalus cabeda growth suggested that at this site mercury accumulation occurs in these organisms since they are very young.     

Organochlorine and organophosphorus pesticide residues in the Atoya river basin, Chinandega, Nicaragua

The hydrographic basin of the Atoya river, located in the Department of Chinandega, one of the main cotton producing regions in Nicaragua, is intensively contaminated by pesticides. Samples of river waters and sediments, as well as strategically selected wells have been analyzed to study variations in the concentrations of organochlorine and organophosphorus pesticide residues between the dry season (November-April) and the rainy season (May-June). Generally, higher concentrations of pesticides have been detected in the river waters and sediments in the dry season. DDT, DDD, DDE compounds and toxaphene are the most frequent organochlorine residues found in the water and sediment samples, while endrin, aldrin, dieldrin and lindane are mainly found in the waters of rivers and wells. Organophosphorus compounds were rarely detected. However, residues of ethion, methyl-parathion and ethyl-parathion were found in high concentrations in some river and well water samples. Generally, organochlorine compounds tend to accumulate in the fine grain-size fractions, rich in organic matter, except DDE, which concentrates basically in the coarse grain-size fractions.     

Water Security in Uzbekistan: Implication of Return Waters on the Amu Darya Water Quality

- DOI: http://dx.doi.org/10.1065/espr2006.01.007 Goal, Scope and Background Amu Darya river, one of the main water resources of Uzbekistan, shows a relevant longitudinal enrichment of soluble contents which strongly limits the human uses of its waters. Because of the low natural run-off processes, salts and pollutants are mainly driven to the river by the return waters used for washing and irrigating the surrounding lands. The influence of return waters on stream quality is dramatically relevant in the lower reaches of the river where almost all the flowing waters have been previously used for the agriculture practises. To provide analytical evidence on the potential effects of return waters on the quality of the Amu Darya river, the paper reports and comments data on salinity and metals contents of the waters flowing in the artificial channel network of Bukhara and in the Amu Darya river, from Bukhara up to the dam forming the Tuyamuyn Hydro Complex (THC). Methods A total of 15 sampling sites were selected for the analytical survey: Two sites were located on the Amu Darya river downstream from the inflow of the return waters from Bukhara, two in the river entering in the THC, and three downstream from the dam forming the reservoir complex. The waters entering and leaving the Bukhara agricultural area were sampled in two main collectors, while the waters flowing in the channel system were sampled in six distinct collectors. The following parameters were considered in the survey: pH, Oxygen, Hardness, Salinity, Conductivity, P-PO4 3–, P tot, N tot, N-NO3 2–, N-NO2 –, COD, Ca2+, Mg2+, Fe, Mn, Zn, Cr, Cu, Ni, Cd, Pb. Results and Discussion Salt concentrations below 1000 mg/l were measured in the Amu Darya waters upstream to Bukhara. In the drainage system, salinity exceeds the palatability limit and reaches the maximum peak of 3200 mg/l in the outflow collector. Due to dilution effects, salinity returns to lower values (400–700 mg/l) along the Amu Darya river downstream from Bukhara; calcium and magnesium resulted the major constituents of the overall salinity. No serious metal contaminations were detected in the waters entering and leaving the examined channel system. Differently, the Amu Darya waters upstream to the THC showed a relevant metal contamination, with Cr, Ni, Fe concentrations exceeding the limits for human consumption. In the downstream sites, located in the Tuyamuyn Hydro Complex and in the Amu Darya river flowing out from this reservoir, excluding Fe, all the examined metals showed lover concentrations and values below the normative limits. Conclusion The direct human consumption of the lower Amu Darya waters is strongly limited by salinity and by metal contamination. Although the salinity of the return waters from the Bukhara drainage system results in above normal limits, no corresponding increases were measured in the Amu Darya river downstream from the return water inflow at the time of the survey. As for the metal contamination of the Amu Darya river, the survey revealed the presence of relevant sources of metal contamination downstream from Bukhara external to the agricultural drainage system. This contamination resulted in reduced sedimentation processes taking place in the limnetic zones of the Amu Darya river upstream to the dam forming the Tuyamuyn Hydro Complex. Recommendation and Outlook To fully understand the longitudinal increase of Amu Darya salinity, an evaluation of the cumulative effects of the loads from the main agricultural areas is required, also by using mass-balance models. As for the metals, an investigation should be addressed to identify the anthropogenic sources of contaminations present in the lower Amu Darya region and the metal loads should be diverted.     

Perfluorooctane surfactants in waste waters, the major source of river pollution

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent and widely distributed in the environment. Recently, the discharge of municipal waste water has been shown to be an important route of such perfluoroalkyl surfactants into the aquatic environment. The aim of this study was to assess the mass flow of PFOA and PFOS from typical waste water treatment plants (WWTPs) into surface waters. Samples were collected at different stages of treatment of four WWTPs in Northern Bavaria, Germany, and from the rivers receiving the treated waste waters (WW). The outflow of PFOA from the WWTPs to the rivers was 20-fold higher than the inflow to the plants; about a tenth was removed with the sludge. For PFOS, the increase from inlet to outlet was about 3-fold; almost half of it was retained in the sludge. Both surfactants were released into river water from the WWTP of a medium-sized city with domestic, industrial and commercial waste waters; in domestic waste waters the surfactants were found at much lower levels.     

Polycyclic aromatic hydrocarbons in wastewater, WWTPs effluents and in the recipient waters of Beijing, China

In this study, surface water samples from the Wenyu River and the North Canal, effluent from major wastewater treatment plants (WWTPs) in Beijing, and wastewater from open sewers that discharge directly into the river system were collected and analyzed for 16 priority USEPA polycyclic aromatic hydrocarbons (PAHs). Concentrations of these 16 PAHs ranged from 193 to 1790 ng/L in river surface waters, 245 to 404 ng/L in WWTP effluents, and 431 to 2860 ng/L in the wastewater from the small sewers. The WWTP effluent was the main contributor of dissolved PAHs to the river, while wastewater from the small sewers contributed both dissolved and suspended particulate matter-associated PAH to the river as indicated by the high dissolved organic carbon and suspended particulate matter contents in the wastewater. Although the flow from each open sewer was small, a PAH discharge as high as 44 kg/year could occur into the river from these types of sewers. This amount was equivalent to about 22 % of the PAH loads discharged into the North Canal downstream from Beijing, whereas the remainder was mainly released by the major WWTPs in Beijing.     

Boron pollution due to geothermal wastewater discharge into the Buyuk Menderes river, Turkey

Kizildere, which is the only commercial geothermal power plant in Turkey and located in Buyuk Menderes Graben in south-west Turkey, discharges annually 6 million tonnes of wastewater into the Buyuk Menderes river, creating environmental pollution. Currently, the wastewater, which includes up to 24 mg/l boron, is discharged into the river at a rate of 750–1500 tonnes per hour. The temperature of the wastewater is approximately 1401°C. The water quality of Buyuk Menderes river is very important for the environment and aquatic life. Reinjection seems to be the only possible solution to this environmental problem.     

Field calibration of surface: A model of agricultural chemicals in surface waters

Abstract

Agricultural chemicals sporadically occur at detectable levels in the surface waters of intensively farmed watersheds. HSPF, a previously released model of agricultural chemicals in surface water, had been used to predict concentrations which were much higher (10 X) than those actually observed during monitoring studies. A new model, SURFACE, is described here which is much simpler than HSPF and gives better predictions of surface water concentrations. SURFACE uses PRZM, an EPA model, to calculate edge‐of‐field runoff losses and simple hydraulic routing algorithms to determine concentrations at the bottom of large river basins. In water systems sampled during 1985 and 1986, SURFACE predictions of annualized mean concentrations for alachlor, atrazine, cyanazine and metolachlor were within 0.09 ppb half of the time.     

Competitive removal of pharmaceuticals from environmental waters by adsorption and photocatalytic degradation

This work explores the competitive removal of pharmaceuticals from synthetic and environmental waters by combined adsorption-photolysis treatment. Five drugs usually present in waterways have been used as target compounds, some are pseudo-persistent pollutants (carbamazepine, clofibric acid, and sulfamethoxazole) and others are largely consumed (diclofenac and ibuprofen). The effect of the light source on adsorption of drugs onto activated carbons followed by photolysis with TiO₂ was assessed, being UV-C light the most effective for drug removal in both deionized water and river water. Different composites prepared from titania nanoparticles and powdered activated carbons were tested in several combined adsorption-photocatalysis assays. The composites prepared by calcination at 400 °C exhibited much better performance than those synthesized at 500 °C, being the C400 composite the most effective one. Furthermore, some synthetic waters containing dissolved species and environmental waters were used to investigate the effect of the aqueous matrix on each drug removal. In general, photocatalyst deactivation was found in synthetic and environmental waters. This was particularly evident in the experiments performed with bicarbonate ions as well as with wastewater effluent. In contrast, tests conducted in seawater showed adsorption and photocatalytic degradation yields comparable to those obtained in deionized water. Considering the peculiarities of substrate competition in each aqueous matrix, the combined adsorption-photolysis treatment generally increased the overall elimination of drugs in water.     

Technogenic load in small river watersheds in the Hibiny Mountains

Pollution loads and morphological changes in the Hibiny mountains ecosystems, one of the most industrially developed regions of the Russian North, were studied using landscape geochemical methods. Principal pollutants come from the local apatite-nepheline ore mining and processing industry which is responsible for mechanical disturbances as well. Some pollutants (Cu, Ni, Co, sulphur etc.) reach the territory because of long-range air transport from the Monchegorsk smelters. Different environmental media were sampled. Seven hydrochemical regions were distinguished, based on chemical composition of local small rivers. Hydrochemical composition of the most polluted of them is controlled by industrial polluted water discharges. The most polluted rivers are: B.Belaya, the lower parts of Loparskaya, Juksporiok etc. Lakes Umb and Imandra receive high amounts of different polluters with river waters. Pollutant loads at small river watersheds depend on height and aspect of mountain slopes. The internal mountain watersheds are the cleanest as a rule. Heightened air pollutant accumulation is typical for the height of 600-800 and 500 m due to atmospheric circulation patterns. Using GIS technologies, a synthetic map of technogenic loads in the Hibiny mountain region was compiled.     

The biodegradation of morpholine in river water and activated sludge

The ability of microorganisms in a wide range of river waters and activated sludges to degrade the heterocyclic compound morpholine was determined by die-away tests and also by most probable number counts of the morpholine degrading microbes. All activated sludges were capable of morpholine degradation but the rate at which degradation occurred could not be related to the type of influent treated. Nearly all river waters contained morpholine degrading microbes which could degrade morpholine in die-away tests. Generally, biodegradation of morpholine occurred more rapidly the further down stream the sample was taken. Morpholine degradation rates could not, however, be related to the immediate severity of pollution (as measured by National Water Council (NWC) classification) at any sampling site. It may be that morpholine degradation rate is related to the cumulative effects of successive discharges of polluting effluents rather than the immediate effect of any particular discharge. Clearly, the capacity to degrade morpholine exists in rivers and activated sludges from sewage works; in practice, however, the rates of degradation observed are very low and it is unlikely that significant morpholine biodegradation generally occurs in these systems.     

Evaluating the fish safety level of river water and wastewater with a larval medaka assay

A larval medaka (Oryzias latipes) assay was proposed to evaluate the fish safety level of river waters and wastewaters. Organic toxicants were 10-100 times concentrated with adsorption cartridges from 4 l of river water or 1-10 times concentrated from 400 ml of wastewater. Toxicity of these concentrated solutions was determined by exposing 48-72 h post-hatch age larvae for 48 h. The method effectively revealed a variation of the median lethal concentration ratio (LCR50) from 13 to >100 in 125 river water samples, and from <1 to >10 in five typical wastewater samples. Ayase River, which takes water mostly from agricultural or household discharge, showed significantly (P<0.001) lower LCR50 than Sagami River that takes natural water as the source. Safety Levels in both Sagami River and Ayase River were influenced by the irrigation activity, LCR50 at some sites showing a seasonal-specific decrease in winter. Pollution from pulp and paper industries contributed to the low LCR50 in several tributaries of Ayase River. Required little manpower in sampling, pretreatment and testing, the proposed larval medaka assay was proved as an efficient tool for screening those high risk sites for priority management.