Perchlorate uptake by salt cedar (Tamarix ramosissima) in the Las Vegas wash riparian ecosystem

Perchlorate ion (ClO4-) has been identified in samples of dormant salt cedar (Tamarix ramosissima) growing in the Las Vegas Wash. Perchlorate is an oxidant, but its reduction is kinetically hindered. Concern over thyroid effects caused the Environmental Protection Agency (EPA) to add perchlorate to the drinking water Contaminant Candidate List (CCL). Beginning in 2001, utilities will look for perchlorate under the Unregulated Contaminants Monitoring Rule (UCMR). In wood samples acquired from the same plant growing in a contaminated stream, perchlorate concentrations were found as follows: 5-6 microg g(-1) in dry twigs extending above the water and 300 microg g(-1) in stalks immersed in the stream. Perchlorate was leached from samples of wood, and the resulting solutions were analyzed by ion chromatography after clean-up. The identification was confirmed by electrospray ionization mass spectrometry after complexation of perchlorate with decyltrimethylammonium cation. Because salt cedar is regarded as an invasive species, there are large scale programs aimed at eliminating it. However, this work suggests that salt cedar might play a role in the ecological distribution of perchlorate as an environmental contaminant. Consequently, a thorough investigation of the fate and transport of perchlorate in tamarisks is required to assess the effects that eradication might have on perchlorate-tainted riparian ecosystems, such as the Las Vegas Wash. This is especially important since water from the wash enters Lake Mead and the Colorado River and has the potential to affect the potable water source of tens of millions of people as well as irrigation water used on a variety of crops, including much of the lettuce produced in the USA.     

Effect of backwashing on perchlorate removal in fixed bed biofilm reactors

The influence of backwashing on biological perchlorate reduction was evaluated in two laboratory scale fixed bed biofilm reactors using 1- or 3-mm glass beads as support media. Influent perchlorate concentrations were 50 microg/L and acetate was added as the electron donor at a concentration of 2 mg C/L. Perchlorate removal was evaluated at various influent dissolved oxygen (DO) concentrations. Complete perchlorate removal was achieved with an influent DO concentration of 1mg/L resulting in bulk phase DO concentrations below the detection limit of 0.01 mg/L. The influence of increasing influent DO concentrations for 12 h periods was evaluated before and after individual backwash events. Partial perchlorate removal was achieved with an influent DO concentration of 3.5 mg/L before a strong backwash (bulk phase DO concentrations of approximately 0.2mg/L), while no perchlorate removal was observed after the strong backwash at the same influent DO level (bulk phase DO concentrations of approximately 0.8 mg/L). The immediate effect of backwashing depended on influent DO concentrations. With influent DO concentrations of 1 mg/L, strong backwashing resulted in a brief (<12 h) increase of effluent perchlorate concentrations up to 20 microg/L; more pronounced effects were observed with influent DO concentrations of 3mg/L. Daily weak backwashing had a small and, over time, decreasing negative influence on perchlorate reduction, while daily strong backwashing ultimately resulted in the breakdown of perchlorate removal with influent DO concentrations of 3 mg/L.     

Microbial reduction of perchlorate in pure and mixed culture packed-bed bioreactors

Perchlorate (ClO4-) has been detected in a large number of surface and ground waters in the US. Due to health concerns of perchlorate in drinking water, the California Department of Health Services has established a provisional action level of 18 microg/L. Several microbial isolates have been obtained capable of microbiological perchlorate reduction through cell respiration, but few of these have been tested for perchlorate removals to these low levels. The feasibility of using one isolate (KJ) for water treatment was tested in a packed-bed bioreactor by comparing minimum detention times necessary to achieve complete removal of perchlorate. Perchlorate was reduced approximately from 20 mg/L to non-detectable (< 4 microg/L) levels in acetate-fed columns inoculated with KJ or mixed cultures. The complete conversion of perchlorate to chloride was demonstrated by a stoichiometric ratio of perchlorate to chloride of 1.0 +/- 0.14. Perchlorate removal to non-detectable levels required a minimum empty bed contact time (EBCT) of only 2.1 min for the column inoculated with KJ, vs. 31 min for the mixed culture column. Acetate was used at a molar ratio of C2H3O2-/ClO4- of 2.9 (n = 6) for the mixed culture, while more than twice as much acetate was consumed on average (6.6 +/- 2.0, n = 156) by the pure culture. These results demonstrate that detention times of packed-bed bioreactors can be substantially reduced using isolate KJ, but that larger concentrations of acetate will be necessary to reduce perchlorate to low levels necessary for drinking water.     

Chemisorption of oxygen onto activated carbon can enhance the stability of biological perchlorate reduction in fixed bed biofilm reactors

Fixed bed biofilm reactors with granular activated carbon (GAC) or glass beads as support media were used to evaluate the influence of short-term (12h) and long-term (23 days) increases of influent dissolved oxygen (DO) concentrations on biological perchlorate removal. The goal was to evaluate the extent by which chemisorption of oxygen to GAC can enhance the stability of biological perchlorate reduction. Baseline influent concentrations were 50 microg/L of perchlorate, 2 mg/L of acetate as C, and 1mg/L of DO. Perchlorate removal in the glass bead reactor seized immediately after increasing influent DO concentrations from 1 to 4 mg/L since glass beads have no sorptive capacity. In the biologically active carbon (BAC) reactor, chemisorption of oxygen to GAC removed a substantial fraction of the influent DO, and perchlorate removal was maintained during short-term increases of influent DO levels up to 8 mg/L. During long-term exposure to influent DO concentrations of 8.5mg/L, effluent perchlorate and DO concentrations increased slowly. Subsequent exposure of the BAC reactor bed to low DO concentrations partially regenerated the capacity for oxygen chemisorption. Microbial analyses indicated similar microbial communities in both reactors, which confirmed that the differences in reactor performance during dynamic loading conditions could be attributed to the sorptive properties of GAC. Using a sorptive biofilm support medium can enhance biological perchlorate removal under dynamic loading conditions.     

Seasonal variation in drinking water concentrations of disinfection by-products in IZMIR and associated human health risks

Seasonal variation in concentrations of two different disinfection by-product groups, trihalomethanes (THMs) and haloacetonitriles (HANs), was investigated in tap water samples collected from five sampling points (one groundwater and four surface water sources) in Izmir, Turkey. Estimates of previously published carcinogenic and non-carcinogenic risks through oral exposure to THMs were re-evaluated using a probabilistic approach that took the seasonal concentration variation into account. Chloroform, bromoform, dibromochloromethane and dichloroacetonitrile were the most frequently detected compounds. Among these, chloroform was detected with the highest concentrations ranging from 0.03 to 98.4 microg/L. In tap water, at the groundwater supplied sampling point, brominated species, bromoform and dibromoacetonitrile, were detected at the highest levels most probably due to bromide ion intrusion from seawater. The highest total THM and total HAN concentrations were detected in spring while the lowest in summer and fall. The annual average total THM concentration measured at one of the surface water supplied sampling points exceeded the USEPA's limit of 80 microg/L. While all non-carcinogenic risks due to exposure to THMs in Izmir drinking water were negligible, carcinogenic risk levels associated with bromodichloromethane and dibromochloromethane were higher than one in million.     

Perchlorate in raw and drinking water sources in England and Wales

A well‐known use of perchlorate is as a rocket fuel propellant; however, more widespread uses include in munitions and fireworks, and it also occurs naturally. Perchlorate suppresses the thyroid, which can lead to a variety of adverse effects. It is a widespread contaminant in the United States, but limited occurrence data in the United Kingdom exist, and even less for drinking water. Monitoring of 20 raw and treated drinking water sites in England and Wales, covering four seasonal periods, showed that perchlorate is a low‐level background contaminant of raw and treated drinking water. Low concentrations (treated drinking water: <0.020–2.073 μg/L, mean 0.747 μg/L) were detected at every higher‐risk site. The concentrations were comparable in each of the four sampling exercises and no significant trends were apparent relating to the time of year, the type of risk or the method of chlorination. Limited data showed that removal by ion exchange and granular‐activated carbon may occur.     

Investigation of pharmaceuticals in Missouri natural and drinking water using high performance liquid chromatography-tandem mass spectrometry

A comprehensive method has been developed and validated in two different water matrices for the analysis of 16 pharmaceutical compounds using solid phase extraction (SPE) of water samples, followed by liquid chromatography coupled with tandem mass spectrometry. These 16 compounds include antibiotics, hormones, analgesics, stimulants, antiepileptics, and X-ray contrast media. Method detection limits (MDLs) that were determined in both reagent water and municipal tap water ranged from 0.1 to 9.9 ng/L. Recoveries for most of the compounds were comparable to those obtained using U.S. EPA methods. Treated and untreated water samples were collected from 31 different water treatment facilities across Missouri, in both winter and summer seasons, and analyzed to assess the 16 pharmaceutical compounds. The results showed that the highest pharmaceutical concentrations in untreated water were caffeine, ibuprofen, and acetaminophen, at concentrations of 224, 77.2, and 70 ng/L, respectively. Concentrations of pharmaceuticals were generally higher during the winter months, as compared to those in the summer due, presumably, to smaller water quantities in the winter, even though pharmaceutical loadings into the receiving waters were similar for both seasons.     

Evaluation of the fate of perfluoroalkyl compounds in wastewater treatment plants

Recent studies have shown that the wastewater treatment plant (WWTP) is a significant source of perfluoroalkyl compounds (PFCs) in natural water. In this study, 10 PFCs were analyzed in influent and effluent wastewater and sludge samples in 15 municipal, 4 livestock and 3 industrial WWTPs in Korea. The observed distribution pattern of PFCs differed between the wastewater and sludge samples. Perfluorooctane sulfonate (PFOS) was dominant in the sludge samples with a concentration ranging from 3.3 to 54.1 ng/g, whereas perfluorooctanoic acid (PFOA) was dominant in wastewater and ranged from 2.3 to 615 ng/L and 3.4 to 591 ng/L in influent and effluent wastewater, respectively. Principal component analysis (PCA) results provided an explanation for this variation in PFC distribution patterns in the aqueous and sludge samples. The fates of PFCs in the WWTPs were related with the functional groups. The PFOS concentrations tended to decrease after treatment in most WWTPs, whereas PFOA increased. The different fates of PFOA and PFOS in WWTPs were attributed to the higher organic carbon-normalized distribution coefficient of perfluoroalkylsulfonate (PFASs) than that of the carboxylate analog, indicating the preference of PFASs to partition to sludge. Although industrial WWTPs contained high concentration of PFCs, they are not the main source of PFCs in Korean water environment because of their small release amount. WWTPs located in big cities discharged more PFCs, suggesting household sewage is one of the significant sources of PFCs contamination in the environment.     

Mercury concentrations in water from an unconfined aquifer system, New Jersey coastal plain

Concentrations of total mercury (Hg) from 2 microg/L (the USEPA maximum contaminant level) to 72 microg/L in water from about 600 domestic wells in residential parts of eight counties in southern New Jersey have been reported by State and county agencies. The wells draw water from the areally extensive (7770 km(2)) unconfined Kirkwood-Cohansey aquifer system, in which background concentrations of Hg are about 0.01 microg/L or less. Hg is present in most aquifer materials at concentrations <50 microg/kg, but is at 100--150 microg/kg in undisturbed surficial soils. No point sources of contamination to the affected areas have been conclusively identified. To determine whether high levels of Hg in ground water are related to a particular land use and (or) water chemistry, water samples from 105 wells that tap the aquifer system were collected by the United States Geological Survey. These included randomly selected domestic wells, domestic and observation wells in selected land uses, and sets of clustered observation wells--including two sets that are downgradient from residential areas with Hg-contaminated ground water. Hg concentrations in filtered samples (Hg(f)) were at or near background levels in water from most wells, but ranged from 0.1 to 3.8 microg/L in water from nearly 20% of wells. Hg(f) concentrations from 0.0001 to 0.1 microg/L correlated significantly and positively with concentrations of other constituents associated with anthropogenic inputs (Ca, Cl, Na, and NO(3)) and with dissolved organic carbon. Hg(f) concentrations >0.1 microg/L did not correlate significantly with concentrations of the inorganic constituents. Hg(f) concentrations near or exceeding 2 microg/L were found only in water from wells in areas with residential land use, but concentrations were at background levels in most water samples from undeveloped land. The spatial distribution of Hg-contaminated ground water appears to be locally and regionally heterogeneous; no extensive plumes of Hg contamination have yet been identified.     

Determining estrogenic steroids in Taipei waters and removal in drinking water treatment using high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry

River water and wastewater treatment plant (WWTP) effluents from metropolitan Taipei, Taiwan were tested for the presence of the pollutants estrone (E1), estriol (E3), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2) using a new methodology that involves high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry. The method was also used to investigate the removal of the analytes by conventional drinking water treatment processes. Without adjusting the pH, we extracted 1-L samples with PolarPlus C18 Speedisks under a flow rate exceeding 100 mL/min, in which six samples could be done simultaneously using an extraction station. The adsorbent was washed with 40% methanol/60% water and then eluted by 50% methanol/50% dichloromethane. The eluate was concentrated until almost dry and was reconstituted by 20 microL of methanol. Quantitation was done by LC-MS/MS-negative electrospray ionization in the selected reaction monitoring mode with isotope-dilution techniques. The mobile phase was 10 mM N-methylmorpholine aqueous solution/acetonitrile with gradient elution. Mean recoveries of spiked Milli-Q water were 65-79% and precisions were within 2-20% of the tested concentrations (5.0-200 ng/L). The method was validated with spiked upstream river water; precisions were most within 10% of the tested concentrations (10-100 ng/L) with most RSDs<10%. LODs of the environmental matrixes were 0.78-7.65 ng/L. A pre-filtration step before solid-phase extraction may significantly influence the measurement of E1 and EE2 concentrations; disk overloading by water matrix may also impact analyte recoveries along with ion suppression. In the Taipei water study, the four steroid estrogens were detected in river samples (ca. 15 ng/L for E2 and EE2 and 35-45 ng/L for E1 and E3). Average levels of 19-26 ng/L for E1, E2, and EE2 were detected in most wastewater effluents, while only a single effluent sample contained E3. The higher level in the river was likely caused by the discharge of untreated human and farming waste into the water. In the drinking water treatment simulations, coagulation removed 20-50% of the estrogens. An increased dose of aluminum sulfate did not improve the performance. Despite the reactive phenolic moiety in the analytes, the steroids were decreased only 20-44% of the initial concentrations in pre- or post-chlorination. Rapid filtration, with crushed anthracite playing a major role, took out more than 84% of the estrogens. Except for E3, the whole procedure successfully removed most of the estrogens even if the initial concentration reached levels as high as 500 ng/L.     

Untersuchung ausgew?hlter Oberfl?chen-, Grund- und?Bodenwasserproben auf Perchlorat in Deutschland: Erste?Ergebnisse

Perchlorate is a component found in solid rocket fuels, explosives, fireworks, and road flares. In addition, perchlorate is a minor component of natural salt deposits in semiarid and arid regions. Discharge and storage areas as well as accidents are potential sources for perchlorate contamination of aquatic systems. Perchlorate has been detected in surface water and groundwater from several places worldwide. The aim of this study is to evaluate whether perchlorate occurs in surface water, groundwater, or soil leachate at selected sites in Germany. These sites include surface water from a military base in southern Germany, groundwater from a production site, and groundwater and soil leachate from a location where fireworks shows are performed regularly. Results show that perchlorate was detected in all surface water and groundwater samples with values around 1???g/l. Highest values (up to 15,000???g/l) were detected in pore waters of the ??Maifeld?? area in Berlin where soil was sampled immediately after a fireworks show.     

Chemistry of trace elements in coalbed methane product water

Extraction of methane (natural gas) from coal deposits is facilitated by pumping of aquifer water. Coalbed methane (CBM) product water, produced from pumping ground water, is discharged into associated unlined holding ponds. The objective of this study was to examine the chemistry of trace elements in CBM product water at discharge points and in associated holding ponds across the Powder River Basin, Wyoming. Product water samples from discharge points and associated holding ponds were collected from the Cheyenne River (CHR), Belle Fourche River (BFR), and Little Powder River (LPR) watersheds during the summers of 1999 and 2000. Samples were analyzed for pH, Al (aluminum), As (arsenic), B (boron), Ba (barium), Cr (chromium), Cu (copper), F (fluoride), Fe (iron), Mn (manganese), Mo (molybdenum), Se (selenium), and Zn (zinc). Chemistry of trace element concentrations were modeled with the MINTEQA2 geochemical equilibrium model. Results of this study show that pH of product water for three watersheds increased in holding ponds. For example the pH of CBM product water increased from 7.21 to 8.26 for LPR watershed. Among three watersheds, the CBM product water exhibited relatively less change in trace element concentrations in CHR watershed holding ponds. Concentration of dissolved Al, Fe, As, Se, and F in product water increased in BFR watershed holding ponds. For example, concentration of dissolved Fe increased from 113 to 135 microg/L. Boron, Cu, and Zn concentrations of product water did not change in BFR watershed holding ponds. However, concentration of dissolved Ba, Mn, and Cr in product water decreased in BFR watershed holding ponds. For instance, Ba and Cr concentrations decreased from 445 to 386 microg/L and from 43.6 to 25.1 microg/L, respectively. In the LPR watershed, Al, Fe, As, Se, and F concentrations of product water increased substantially in holding ponds. For example, Fe concentration increased from 192 to 312 microg/L. However, concentration of dissolved Ba, Mn, Cr, and Zn decreased in holding ponds. Geochemical modeling calculations suggested that observed increase of Al and Fe concentrations in holding ponds was due to increase in concentration of Al(OH)(4)(-) and Fe(OH)(4)(-) species in water which were responsible for pH increases. Decreases in Ba, Mn, Cr, and Zn concentrations were attributed to the increase in pH, resulting in precipitates of BaSO(4) (barite), MnCO(3) (rhodochrosite), Cr(OH)(2) (chromium hydroxide), and ZnCO(3) (smithsonite) in pond waters, respectively.     

Adsorption of perchlorate and other oxyanions onto magnetic permanently confined micelle arrays (Mag-PCMAs)

The removal of oxyanions found in drinking water sources -perchlorate, nitrate, phosphate, and sulfate- onto magnetic permanently confined micelle arrays (Mag-PCMAs) was studied. We determined the removal efficiency in both competitive and non-competitive environments, as many of these anions are present in these sources. Mag-PCMA removed over 98% of the aqueous perchlorate anions across a concentration range of 60-500 μg/L. Nitrate was absorbed 100% over a concentration range of 10-35 mg/L as nitrate. Removal of phosphate was 95.7% for 0.2-2.45 mg/L as phosphate. Sulfate was 100% absorbed across a concentration range of 5-20 mg/L and an average 75.7% for 5-50 mg/L. The sorption isotherms followed a Freundlich relationship with K_f values of 2.00, 2.05, 1.9, and 3.86 mg/g for nitrate, perchlorate, phosphate, and sulfate respectively. Perchlorate and nitrate did not compete significantly for binding on Mag-PCMAs, with almost equal sorption, greater than 90%, for both anions in elevated concentrations. This is a distinguishing feature from ion exchange resins or activated carbon with cationic surfactants, where these anions have been shown to compete for sorption sites. At the concentrations studied, phosphate and sulfate also do not exhibit significant competition. Desorption for reuse was successful at pH 10. This reusable magnetic sorbent can thus be used to rapidly remove target anions such as perchlorate from water in the presence or absence of other oxyanions.     

Perchlorate removal in sand and plastic media bioreactors

The treatment of perchlorate-contaminated groundwater was examined using two side-by-side pilot-scale fixed-bed bioreactors packed with sand or plastic media, and bioaugmented with the perchlorate-degrading bacterium Dechlorosoma sp. KJ. Groundwater containing perchlorate (77microg/L), nitrate (4mg-NO(3)/L), and dissolved oxygen (7.5mg/L) was amended with a carbon source (acetic acid) and nutrients (ammonium phosphate). Perchlorate was completely removed (<4microg/L) in the sand medium bioreactor at flow rates of 0.063-0.126L/s (1-2gpm or hydraulic loading rate of 0.34-0.68L/m(2)s) and in the plastic medium reactor at flow rates of <0.063L/s. Acetate in the sand reactor was removed from 43+/-8 to 13+/-8mg/L (after day 100), and nitrate was completely removed in the reactor (except day 159). A regular (weekly) backwashing cycle was necessary to achieve consistent reactor performance and avoid short-circuiting in the reactors. For example, the sand reactor detention time was 18min (hydraulic loading rate of 0.68L/m(2)s) immediately after backwashing, but it decreased to only 10min 1 week later. In the plastic medium bioreactor, the relative changes in detention time due to backwashing were smaller, typically changing from 60min before backwashing to 70min after backwashing. We found that detention times necessary for complete perchlorate removal were more typical of those expected for mixed cultures (10-18min) than those for the pure culture (<1min) reported in our previous laboratory studies. Analysis of intra-column perchlorate profiles revealed that there was simultaneous removal of dissolved oxygen, nitrate, and perchlorate, and that oxygen and nitrate removal was always complete prior to complete perchlorate removal. This study demonstrated for the first time in a pilot-scale system, that with regular backwashing cycles, fixed-bed bioreactors could be used to remove perchlorate in groundwater to a suitable level for drinking water.     

Occurrence of ionophore antibiotics in water and sediments of a mixed-landscape watershed

Analytical methods for quantifying three ionophore antibiotics, monensin, salinomycin, and narasin, were developed for water and sediment matrices. Sample preparation was based on solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS) was used to separate and detect the compounds. Recoveries ranged from 83% to 117% for water and from 51% to 105% for sediment in three different concentrations with less than 10% of relative standard deviation. The statistical detection limit was 0.001-0.003 microg/L for water and 0.4-3.6 microg/kg for sediment. Ionophore antibiotics are only used to treat coccidiostats for broilers or turkeys, and to increase growth and feed efficiency for beef and dairy cattle. Since they are not used for human purposes, these compounds can act as markers for the transport of animal pharmaceuticals to the watershed. The occurrence of three ionophore compounds was determined at five sampling sites along the Cache la Poudre River in Northern Colorado representing pristine, urban, and agriculture landscapes. Statistical analysis demonstrates that the measured concentration was significantly different among sampling sites in different sampling events for both water and sediment. In addition, significant differences were observed among different sampling times at each sampling site. Furthermore, all three ionophores were found in the sediments at much higher concentrations than in water indicating the importance of this matrix when determining environmental impacts.     

Part I. Identifying anthropogenic markers in surface waters influenced by treated effluents: a tool in potable water reuse

In potable water reuse, treated wastewater becomes part of the drinking water supply. An important question associated with this practice is whether or not the organic quality of the treated wastewater is chemically different from that of non-human impacted water. This question was addressed in a case study of indirect potable water reuse where the organic matrix of the South Platte River was analyzed upstream and downstream of the discharge of treated wastewater effluent using conventional water quality parameters combined with pyrolysis-GC/MS. Effluent-derived organic material (EfOM) was found to be more aliphatic and had higher organic nitrogen and halogen content compared to organic material derived from "natural" (non-anthropogenic) sources (NOM). Seasonal changes that resulted from the change in the contributions of aquatic and terrestrial sources were not observed in EfOM; but they were strongly observed in NOM under the control of natural processes. Using principal component and factor analyses, the pyrolysis fragments of phenol, alkyl-phenols, and acetic acid were identified as the seasonal indicators for the NOM set of samples. In contrast, benzaldehyde, benzonitrile, chlorobutanoic acid, furancarboxaldehyde, and methylfurancarboxaldehyde were identified as the indicators for wastewater inputs for the EfOM set of samples. Overall, the results from conventional water quality parameters and pyrolysis-GC/MS revealed that: (1) EfOM bears a chemical signature distinct from NOM and (2) under the conditions of this study, EfOM discharged to the South Platte River persisted and controlled organic quality at downstream points.     

Characterization and distribution of polycyclic aromatic hydrocarbon contaminations in surface sediment and water from Gao-ping River, Taiwan

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples collected from 12 locations in Gao-ping River, Taiwan were analyzed. Molecular ratios and principal component analysis (PCA) were used to characterize the possible pollution sources. Concentrations of total 16 PAHs (SigmaPAHs) in water samples ranged from below method detection limits (相似文献   

A field study on 8 pharmaceuticals and 1 pesticide in Belgium: Removal rates in waste water treatment plants and occurrence in surface water

Only recently, attention has been drawn towards the occurrence of pharmaceuticals in the environment. In recent years many reports have been made on the occurrence of the large, differentiated group of pharmaceuticals in waste water, surface water, ground water and in soil. In this study, we demonstrate the applicability of a previously developed LC-MS/MS method by evaluating in waste water and surface water samples from Belgium the occurrence of 8 pharmaceuticals and 1 pesticide (flubendazole, pipamperone, rabeprazole, domperidone, ketoconazole, itraconazole, cinnarizine, miconazole and propiconazole). Removal rates in five public waste water treatment plants were assessed. Introduction of several compounds into the aquatic environment by discharge of effluent could be demonstrated. For several compounds, the highest concentrations (up to 35.6 μg/l for pipamperone) were observed in the effluent of a WWTP receiving water from chemo-pharmaceutical and other industrial companies. The occurrence of these compounds in the aquatic environment was assessed by analyzing 16 surface water samples, taken from various locations. Four pharmaceuticals (flubendazole, pipamperone, domperidone and cinnarizine) could be detected in at least one sample at low concentrations (up to 26.4 ng/l). The pesticide propiconazole was found in comparable concentrations (up to 85.9 ng/l) as in effluent, suggesting potential introduction by direct seepage of water from rural grounds. The highest concentrations of flubendazole, pipamperone, domperidone, propiconazole and cinnarizine (up to 961.3 ng/l) were observed in a sample, taken near the discharge of a WWTP receiving water from chemo-pharmaceutical and other industries. An initial environmental risk assessment was done based on these results.     

River water quality of the River Cherwell: an agricultural clay-dominated catchment in the upper Thames Basin, southeastern England

The water quality of the River Cherwell and a tributary of it, the Ray, are described in terms of point and diffuse sources of pollution, for this rural area of the upper Thames Basin. Point sources of pollution dominate at the critical ecological low flow periods of high biological activity. Although the surface geology is predominantly clay, base flow is partly supplied from springs in underlying carbonate-bearing strata, which influences the water quality particularly with regards to calcium and alkalinity. The hydrogeochemistry of the river is outlined and the overall importance of urban point sources even in what would normally be considered to be rural catchments is stressed in relation to the European Unions Water Framework Directive. Issues of phosphorus stripping at sewage treatment works are also considered: such stripping on the Cherwell has reduced phosphorus concentrations by about a factor of two, but this is insufficient for the needs of the Water Framework Directive.     

Use of surfactant modified ultrafiltration for perchlorate (Cl(O)(4-)) removal

Determinations of perchlorate anion (ClO(4)(-)) transport and rejection were performed using a surfactant modified ultrafiltration (UF) membrane. Perchlorate anion (at a concentration of 100 microg/L of ClO(4)(-), spiked with KClO(4)) was introduced to the membrane as a pure component, in binary mixtures with other salts, cationic and anionic surfactants, and at various ionic strength conditions (conductivity). Also, a natural source water was spiked with perchlorate in the presence of cationic and anionic surfactants and used to determine the effects of a complex mixture (including natural organic matter (NOM)) on the observed rejection. All filtration measurements were performed at approximately the same permeate flow rate in order to minimize artifacts from mass transfer at the membrane interface. The objective of this study was to modify a negatively charged UF membrane in terms of the fundamental mechanisms, steric/size exclusion and electrostatic exclusion and to enhance perchlorate rejection, with synthetic water and a blend of Colorado River water and State Project water (CRW/SPW). Previous work suggested that perchlorate was dominantly rejected by electrostatic exclusion for charged nanofiltration (NF) and UF membranes (Rejection of perchlorate by reverse osmosis, nanofiltration and ultrafiltration (UF) membranes: mechanism and modeling. Ph.D. dissertation, University of Colorado, Boulder, USA, 2001). In that research, perchlorate rejection capability was quickly lost in the presence of a sufficient amount of other ions. However, this study showed that ClO(4)(-) was excluded from a (negatively) charged UF membrane with pores large with respect to the size of the ion. Although perchlorate rejection capability due to apparent electrostatic force was reduced in the presence of a cationic surfactant, a desired amount of the ClO(4)(-) was excluded by steric exclusion. The steric exclusion was due to decreasing membrane pore size caused by the adsorption of the cationic surfactant.