Determination of iodide,iodate and organo-iodine in waters with a new total organic iodine measurement approach

The dissolved iodine species that dominate aquatic systems are iodide, iodate and organo-iodine. These species may undergo transformation to one another and thus affect the formation of iodinated disinfection byproducts during disinfection of drinking waters or wastewater effluents. In this study, a fast, sensitive and accurate method for determining these iodine species in waters was developed by derivatizing iodide and iodate to organic iodine and measuring organic iodine with a total organic iodine (TOI) measurement approach. Within this method, organo-iodine was determined directly by TOI measurement; iodide was oxidized by monochloramine to hypoiodous acid and then hypoiodous acid reacted with phenol to form organic iodine, which was determined by TOI measurement; iodate was reduced by ascorbic acid to iodide and then determined as iodide. The quantitation limit of organo-iodine or sum of organo-iodine and iodide or sum of organo-iodine, iodide and iodate was 5 μg/L as I for a 40 mL water sample (or 2.5 μg/L as I for an 80 mL water sample, or 1.25 μg/L as I for a 160 mL water sample). This method was successfully applied to the determination of iodide, iodate and organo-iodine in a variety of water samples, including tap water, seawater, urine and wastewater. The recoveries of iodide, iodate and organo-iodine were 91–109%, 90–108% and 91–108%, respectively. The concentrations and distributions of iodine species in different water samples were obtained and compared.     

Identification and significance of sulphonamides (p-TSA, o-TSA, BSA) in an urban water cycle (Berlin, Germany)

Because of the nature of the water cycle in Berlin, a number of persistent wastewater residues are present in the surface water and may potentially reach the groundwater via bank filtration and artificial recharge. The occurrence and behaviour of the wastewater residues para-toluenesulphonamide (p-TSA), ortho-toluenesulphonamide (o-TSA) and benzenesulphonamide (BSA) through wastewater treatment, surface water, bank filtration and drinking water treatment was studied. In addition, groundwater below a former sewage farm was investigated. All three compounds are ubiquitous in the aquatic environment of Berlin. p-TSA concentrations are much higher than those of o-TSA and BSA. p-TSA was found in high concentrations in the wastewater influent (2 to 15microg/L), in the wastewater effluent (<0.15 to 2.34microg/L) and in sewage farm groundwater (<0.05 to 20microg/L) and in lower concentrations in the surface water (<0.05 to 1.15microg/L), bank filtrate (<0.05 to 0.30microg/L) and drinking water (<0.05 to 0.54microg/L). p-TSA is considerably depleted during waste- and drinking water treatment ( approximately 90% reduction each). The concentration ranges for o-TSA and BSA in wastewater influents were 0.11 to 8microg/L and <0.05 to 0.64microg/L, respectively, while the values for wastewater effluents were 0.14 to 4microg/L for o-TSA and 0.25 to 0.49microg/L for BSA. Wastewater treatment and drinking water treatment do not reduce the concentrations of o-TSA and BSA. The behaviour of o-TSA during wastewater treatment varies largely between different wastewater treatment plants where concentrations increase, remain constant or decrease. BSA forms during treatment. The concentrations measured in surface water, sewage farm groundwater, bank filtrate and drinking water were <0.05 to 1.74microg/L for o-TSA and <0.05 to 0.53microg/L for BSA.     

Evolution of antibiotic occurrence in a river through pristine, urban and agricultural landscapes

A river along the semi-arid Front Range of Colorado was monitored for antibiotics including five tetracycline and six sulfonamide compounds. Existing analytical methods were adapted to measure these compounds in a surface water matrix at environmentally relevant concentrations (0.05 microg/L). Natural organic matter present in surface waters was confirmed to significantly impact the low-level analysis of tetracyclines (TCs) necessitating the use of standard addition quantification techniques. Five sites along the Cache la Poudre River were monitored for antibiotics encompassing pristine areas without anthropogenic influence, urban areas impacted by wastewater discharges and agricultural areas susceptible to non-point source contaminant runoff. The only site at which no antibiotics were detected was the pristine site in the mountains before the river had encountered urban or agricultural landscapes. By the time the river had exited the urban area, 6 of the 11 antibiotic compounds that were monitored were found in the samples. At Site 5, which had both urban and agricultural influences all five of the TCs monitored were detected indicating both urban and agricultural influences. The concentration of TCs at Site 5 ranged from 0.08 to 0.30 microg/L.     

Distribution of linear alkylbenzenes (LABs) in riverine and coastal environments in South and Southeast Asia

This paper reports the result of sewage pollution monitoring conducted in South and Southeast Asia during 1998-2003 using linear alkylbenzenes (LABs) as molecular tracers of sewage contamination. Eighty-nine water samples collected from Malaysia, Vietnam, and Japan (Tokyo), and 161 surface sediment samples collected from Tokyo, Thailand, Malaysia, Philippines, Vietnam, Cambodia, Indonesia, and India were analyzed for alkylbenzenes. The concentration range of SigmaLABs in river water particles in Southeast Asia (<0.005-0.913 microg/L) was comparable to or higher than those found in Tokyo (<0.005-0.638 microg/L). I/E ratios (a ratio of internal to external isomers of LABs) in tropical Asian waters were close to the value of LABs in raw sewage ( approximately 1) and much lower than those in secondary effluents (3-5). This suggests that untreated or inadequately treated sewage is discharged into the water. SigmaLABs concentrations in sediments from South and Southeast Asia ranged from <0.002-42.6 microg/g-dry with the highest concentration occurring at several populous cities. Low I/E ratios of the sediments with high SigmaLABs concentrations suggest a heavy load of untreated sewage. Clearly in view of the current data and evidence of the implications of sewage pollution, this paper highlights the necessity of the continuation of water treatment system improvement in tropical Asia.     

Evaluation of human adenovirus and human polyomavirus as indicators of human sewage contamination in the aquatic environment

Discharge of inadequately treated human wastewater into surface waters used for recreation, drinking water, irrigation and shellfish cultivation may present a public health hazard due to the potential shedding of high concentrations of pathogenic viruses from the human gastrointestinal tract. Human adenovirus (HAdV) and human polyomavirus (HPyV) are ubiquitous in humans and have excellent survival characteristics in the environment, so are potential candidates for indicators of human sewage contamination. Using qPCR assays, the prevalence and quantity of HAdV and HPyV JC and BK were determined in influent and effluent wastewater and receiving waters (river, urban stream, estuarine), then compared with norovirus (NoV) presence, a significant human pathogen which is not necessarily ubiquitously excreted into the environment. HAdV and HPyV were frequently detected in high concentrations in wastewater and wastewater-contaminated waters confirming their use as potential indicators for the presence of human sewage. Overall, there was a correlation between the presence of HAdV and HPyV with NoV but there were some notable exceptions including the higher frequency of NoV compared to HAdV and HPyV in estuarine waters impacted by wastewater overflows. We found that HAdV and HPyV detection by qPCR was a suitable tool for evaluating water quality and that their detection can aid in determining pollution sources, thus providing useful information for health risk assessments.     

Occurrence of phthalates and bisphenol A and F in the environment

Certain xenoestrogens, namely bisphenol A (BPA), bisphenol F (BPF), butylbenzyl phthalate (BBP), dibutyl phthalate (DBP), and di(2-ethylhexyl)phthalate (DEHP), were measured in various compartments (surface water, sediments, sewage treatment plant effluents, sewage sludge, dump water, liquid manure) in order to contribute to a better understanding of exposure to these compounds in different environments. Hundred and sixteen surface-water samples and 35 sediments from rivers, lakes and channels, 39 sewage effluents, and 38 sewage sludges were collected in Germany. Furthermore, ten liquid manure, two waste-dump and two compost-runoff water samples were also analysed. BPA measurements showed low concentrations from 0.0005 to 0.41 microg L(-1) in surface water, in sewage effluents from 0.018 to 0.702 microg L(-1), in sediments from 0.01 to 0.19 mgkg(-1) and in sewage sludge from 0.004 to 1.363mgkg(-1) dw. Measured concentrations of BPF were clearly lower than BPA in all environmental media. DEHP dominated the phthalate concentrations, which ranged from 0.33 to 97.8 microg L(-1) (surface water), 1.74 to 182 microg L(-1) (sewage effluents), 27.9 to 154 mgkg(-1) dw (sewage sludge) and 0.21 to 8.44 mgkg(-1) (sediment). DBP was found only in minor concentrations and BBP, only in a few samples in low amounts. Very high concentrations of BPA and phthalates were confirmed in waste dump water and compost water samples as well as in the liquid manure samples.     

Occurrence of antibiotics in wastewater treatment facilities in Wisconsin, USA

Samples from several wastewater treatment facilities in Wisconsin were screened for the presence of 21 antibiotic compounds. These facilities spanned a range of community size served (average daily flow from 0.0212 to 23.6 million gallons/day), secondary treatment processes, geographic locations across the state, and they discharged the treated effluents to both surface and ground waters (for ground water after a soil passage). A total of six antibiotic compounds were detected (1-5 compounds per site), including two sulfonamides (sulfamethazine, sulfamethoxazole), one tetracycline (tetracycline), fluoroquinolone (ciprofloxacin), macrolide (erythromycin-H(2)O) and trimethoprim. The frequency of detection of antibiotics was in the following order: tetracycline and trimethoprim (80%)>sulfamethoxazole (70%)>erythromycin-H(2)O (45%)>ciprofloxacin (40%)>sulfamethazine (10%). However, the soluble concentrations were in the parts-per-billion (ppb) range (相似文献   

Occurrence and removal of N-nitrosamines in wastewater treatment plants

The presence of nitrosamines in wastewater might pose a risk to water resources even in countries where chlorination or chloramination are hardly used for water disinfection. We studied the variation of concentrations and removal efficiencies of eight N-nitrosamines among 21 full-scale sewage treatment plants (STPs) in Switzerland and temporal variations at one of these plants. N-nitrosodimethylamine (NDMA) was the predominant compound in STP primary effluents with median concentrations in the range of 5-20 ng/L, but peak concentrations up to 1 μg/L. N-nitrosomorpholine (NMOR) was abundant in all plants at concentrations of 5-30 ng/L, other nitrosamines occurred at a lower number of plants at similar levels. From concentrations in urine samples and domestic wastewater we estimated that human excretion accounted for levels of <5 ng/L of NDMA and <1 ng/L of the other nitrosamines in municipal wastewater, additional domestic sources for <5 ng/L of NMOR. Levels above this domestic background are probably caused by industrial or commercial discharges, which results in highly variable concentrations in sewage. Aqueous removal efficiencies in activated sludge treatment were in general above 40% for NMOR and above 60% for the other nitrosamines, but could be lower if concentrations were below 8-15 ng/L in primary effluent. We hypothesize that substrate competition in the cometabolic degradation explains the occurrence of such threshold concentrations. An additional sand filtration step resulted in a further removal of nitrosamines from secondary effluents even at low concentrations. Concentrations released to surface waters were largely below 10 ng/L, suggesting a low impact on Swiss water resources and drinking water generation considering the generally high environmental dilution and possible degradation. However, local impacts in case a larger fraction of wastewater is present cannot be ruled out.     

Medically-derived (131)I in municipal sewage effluent

This work presents ¹³¹I (t_½ = 8.04 d) concentrations in sewage effluent from the Stony Brook Water Pollution Control Plant (WPCP), a small plant serving a regional thyroid cancer treatment facility in Stony Brook, NY, USA. The concentrations detected in sewage effluent ranged from 1.8 ± 0.3 to 227 ± 2 Bq L⁻¹. The primary source of ¹³¹I is excreta from thyroid cancer inpatients treated at the Stony Brook University Medical Center. Based on several time series measurements following known inpatient treatments, the mean sewage half-life (T_s) of iodine is 3 d in this plant. The T_s, analogous to a radioactive half-life, describes the time it takes for half of a wastewater component to be removed from a WPCP. Flow recycling, or activated sludge, used to maintain bacterial populations necessary for sewage treatment causes iodine to remain in this plant far longer than its hydraulic retention time. The experimental results suggest that most ¹³¹I entering the Stony Brook WPCP leaves in sewage effluent, not in sewage sludge. Patient treatments can result in continuous discharges of ¹³¹I to surface waters where it can be used as a tracer of sewage-derived material and to understand the behavior of ¹³¹I in aquatic environments.     

Illicit drugs, a novel group of environmental contaminants

It is now well established that residues from therapeutic drugs consumed by humans can end up, through the sewage system, in the surface water of populated areas. Given that the global production of major illicit drugs is comparable to that of widely used pharmaceuticals, we tested for the presence of drugs of abuse (cocaine, opioids, amphetamines and cannabis derivatives), some related opioid pharmaceuticals (codeine and methadone) and/or their metabolites in Italian and British surface waters. Having identified residues of all major drugs of abuse in raw and treated urban wastewater, we now measured their levels in several rivers and lakes by a selective multi-residue assay based on liquid chromatography-tandem mass spectrometry. Recoveries in surface water were generally higher than 80%, with overall variability of the method lower than 10%. LODs were generally lower than 0.2 ng/L, and LOQs were lower than 0.6 ng/L, with few exceptions. Many of the tested substances were found in both rivers and lakes, at concentrations ranging from high pg/L to high ng/L, with loads in rivers in the range of tenths to hundreds of grams per day. Our data indicate that residues of drugs of abuse have become widespread surface water contaminants in populated areas. Since most of these residues still have potent pharmacological activities, their presence in the aquatic environment may have potential implications for human health and wildlife.     

Occurrence and fate of synthetic musk compounds in water environment

Synthetic musk compounds (SMCs) occur widely in water environments. The aims of this paper were to investigate the occurrence and fate of SMCs in sewage treatment plants (STPs) and surface waters. Total SMC concentrations ranged from 3.69 to 7.33 μg/L (influent) and from 0.96 to 2.69 μg/L (effluent) in 10 STPs. The SMC concentrations varied with the input source and treatment volume of each STP. Biological treatment processes had a greater SMCs removal effect than chemical treatment, filtration and disinfection processes. The SMC concentrations in surface waters ranged from 0.15 to 16.72 μg/L and exhibited similar SMCs occurrence patterns generally. The fate of SMCs in water environments depends on their physical-chemical properties and their concentrations can be predicted from other SMC concentrations due to their similar fates.     

Use of biodegradable dissolved organic carbon (BDOC) to assess the potential for transformation of wastewater-derived contaminants in surface waters

Wastewater-derived contaminants (WWDCs), such as steroid hormones, pharmaceuticals and personal care products, have been detected in surface waters at concentrations that pose potential risks to aquatic ecosystems. To assess the factors controlling biotransformation of these compounds in effluent-dominated surface waters (i.e., surface waters containing a high proportion of wastewater effluent), microcosm experiments were conducted with 10 pharmaceuticals and five steroids typically detected in wastewater effluent. Some of the compounds underwent rapid biotransformation under all conditions (estrone, 17beta-estradiol, progesterone, testosterone and triclosan), while carbamazepine was always resistant to biotransformation. For the remaining compounds, the rate of biotransformation was related to the amount and type of biodegradable dissolved organic carbon (BDOC). The rates of biotransformation of these WWDCs increased as the initial concentration of wastewater BDOC increased, indicating a relationship between microbial activity and biotransformation rate. Furthermore, BDOC derived from aquatic plants resulted in a better ability to remove certain recalcitrant compounds (gemfibrozil and sulfamethoxazole) as compared to that derived from wastewater effluent. These observations indicate that for each source of BDOC, it may be possible to use BDOC for predicting the rate of biotransformation of WWDCs in surface waters.     

Fate of organic micropollutants in the hyporheic zone of a eutrophic lowland stream: results of a preliminary field study

Many rivers and streams worldwide are impacted by pharmaceuticals originating from sewage. The hyporheic zone underlying streams is often regarded as reactive bioreactor with the potential for eliminating such sewage-born micropollutants. The present study aims at checking the elimination potential and analyzing the coupling of hydrodynamics, biogeochemistry and micropollutant processing. To this end, two sites at the lowland stream Erpe, which receives a high sewage burden, were equipped and sampled with nested piezometers. From temperature depth profiles we determined that at one of the sites infiltration of surface water into the aquifer occurs while exfiltration dominates at the other site. Biogeochemical data reveal intense mineralization processes and strictly anoxic conditions in the streambed sediments at both sites. Concentrations of the pharmaceuticals indomethacin, diclofenac, ibuprofen, bezafibrate, ketoprofen, naproxen and clofibric acid were high in the surface water and also in the subsurface at the infiltrating site. The evaluation of the depth profiles indicates some attenuation but due to varying surface water composition the evaluation of subsurface processes is quite complex. Borate and non-geogenic gadolinium were measured as conservative wastewater indicators. To eliminate the influence of fluctuating sewage proportions in the surface water, micropollutant concentrations are related to these indicators. The indicators can cope with different dilutions of the sewage but not with temporally varying sewage composition.     

Concentrations and mobility of human pharmaceuticals in the world's largest wastewater irrigation system, Mexico City-Mezquital Valley

Concentrations and retention of pharmaceutically active substances are crucial for assessing the environmental risk of medication of humans. We hypothesize that environmental introduction concentrations (EICs) of drugs in the Mexico City-Mezquital Valley wastewater irrigation system can be estimated using information on water consumption, sales data, and excretion rates. EICs of six acidic and five basic drugs were calculated and compared with concentrations measured in wastewater, irrigation water, soil drainage, and springs by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). EICs of trimethoprim, erythromycin, naproxen, ibuprofen, and diclofenac in sewage equaled or exceeded the US FDA action limit of 1mug/L for detailed environmental risk assessment (ERA). Concentrations of clarithromycin, clindamycin, metoprolol, sulfasalazine, bezafibrate, and gemfibrozil were smaller. Calculated EICs of all compounds except metoprolol and clarithromycin were comparable to measured concentrations if excretion rates were considered. Whereas concentrations of basic compounds with positive or neutral charges were effectively reduced during reservoir storage and soil passage, acidic, anionic compounds were hardly retained. Though realistic EICs can be predicted for most substances, large deviations between EICs and measured concentrations in the case of metoprolol illustrate that estimated concentrations cannot substitute for monitoring programs.     

Predicted and measured concentrations for selected pharmaceuticals in UK rivers: implications for risk assessment

Predicted environmental concentrations for five commonly used pharmaceuticals were calculated using data from the UK Department of Health according to risk assessment guidelines proposed by the European Agency for the Evaluation of Medicinal Products. Surface waters from the South-East of England were analysed and results were compared with predicted concentrations and findings from other studies from the UK and Europe. It was found that the efficacy of these predictions varied and was hampered by a shortage of data for many of the drugs. Ibuprofen, paracetamol and salbutamol were detected and quantified in all locations sampled. Ibuprofen was consistently found at the highest concentrations (up to 3 microg l(-1)). Levels up and downstream of two wastewater treatment works were compared in order to investigate the link between sewage discharge and environmental concentrations of pharmaceuticals. Results from one site demonstrated a considerable increase in concentrations of ibuprofen, salbutamol and paracetamol downstream from the treatment works; however, no link was established for a second works.     

Mercury contamination in the vicinity of a derelict chlor-alkali plant. Part I: sediment and water contamination of Lake Balkyldak and the River Irtysh

A mercury-cell chlor-alkali plant operated in Pavlodar, Northern Kazakhstan, for 18 years and caused widespread contamination of the surrounding environment. Untreated wastewater from the plant was discharged to Lake Balkyldak, a shallow impounded lake without an outlet. The nearby River Irtysh was also suspected to be impacted by mercury (Hg) via the transport of contaminated groundwater. We took sediment and water samples from both aquatic systems, and also sampled soils along the shoreline of the lake and in the Irtysh flood plain. Sediments from Lake Balkyldak were found to be very heavily contaminated, with Hg concentrations in the surface layer reaching up to approximately 1500 mg kg(-1) near the wastewater outfall pipe. The contaminated lake sediments are prone to wind-driven resuspension and are acting as a strong source of Hg to the water column. Unfiltered lake water samples taken in shallow areas within 10-15 m from the shoreline contained from 0.11 microg Hg L(-1) in the less contaminated northern part of the lake to 1.39 microg L(-1) near the pollutant outfall in the south (up to 7.3 microg L(-1) on windy days). Sediments from the River Irtysh were only slightly impacted, with maximum Hg concentrations of 0.046 mg kg(-1) in the old river channel and 0.36 mg kg(-1) in floodplain oxbow lakes. In water samples from the River Irtysh, Hg was generally not detected, although trace concentrations (3 to 9 ng L(-1)) were found in some samples taken from oxbow lakes. We conclude that the river is not significantly impacted by Hg, but the highly contaminated Lake Balkyldak poses a threat and is in need of remediation. Potential remediation options for the lake are reviewed and are discussed in the context of experiences made at other Hg-contaminated sites.     

Monitoring of opiates, cannabinoids and their metabolites in wastewater, surface water and finished water in Catalonia, Spain

The occurrence of several opiates and cannabinoids in wastewaters and surface waters has been investigated. Most of the compounds (8 out of 11) were identified in both influent and effluents of fifteen wastewater treatment plants (WWTPs). Codeine, morphine, EDDP and methadone were detected in almost all samples with median values of 69 ng/L; 63 ng/L; 28 ng/L and 18 ng/L, respectively, whereas the main cannabinoid metabolite THC-COOH presented a median value of 57 ng/L in influents. A rough estimate of heroin and cannabis consumption was performed from the analysis of target urinary metabolites in wastewater influents. Data obtained from influents of rural and urban WWTPs gave 0.07% of heroin consumption (0.67% for the largest urban WWTP) and 4% consumption of cannabinoids, respectively for the population aged between 15 and 64 years old. The presence of opiates and cannabinoids in surface waters used for drinking water production showed the presence of the same compounds identified in wastewater effluents at concentrations up to 76 ng/L for codeine; 31 ng/L for EDDP; 12 ng/L for morphine and 9 ng/L for methadone at the intake of the DWTP. A complete removal of all studied drugs present in surface water was achieved during the potabilization process except for methadone and EDDP (91% and 87% removal, respectively).     

An investigation into the acute and chronic toxicity of eleven pharmaceuticals (and their solvents) found in wastewater effluent on the cnidarian, Hydra attenuata

Pharmaceuticals previously identified in the effluent from the wastewater treatment plant (WWTP) in Montreal discharging into the St. Lawrence river, were tested for acute and chronic toxicity using the cnidarian Hydra attenuata. Acute toxicity was based on the established technique looking at morphological changes in the Hydra, while recently developed endpoints of feeding behaviour, attachment and growth (hydranth number) were used to measure chronic effects. The compounds under investigation (ibuprofen, naproxen, gemfibrozil, bezafibrate, carbamazepine, sulfamethoxazole, sulfapyridine, oxytetracycline, novobiocin, trimethoprim and caffeine) were tested individually in controlled laboratory exposures with LC(50) and EC(50) results calculated. All compounds tested had relatively high LC(50) values with gemfibrozil, ibuprofen and naproxen having the lowest at 22.36 mg/L and EC(50) values based on morphology of 1.18 to 2.62 mg/L (all concentrations are nominal). The EC(50) values based on feeding were similar to those based on morphology but with increased sensitivity for carbamazepine, bezafibrate and novobiocin. A trend of a reduction in feeding with deterioration in morphology was observed in the Hydra, with the exception of novobiocin, where a lower than expected EC(50) of 13.53 mg/L was found with no negative effect on morphology. Significant reductions in attachment and hydranth number were seen at concentrations of 1 and 5 mg/L for gemfibrozil and ibuprofen respectively. A toxicity threshold (TT) of 320 microg/L was calculated for ibuprofen, only a factor of 10(2) or 10 higher than the concentration found in the effluent in the present study (1.19 mug/L) and in other Canadian effluents studied (22 microg/L [Brun GL, Bernier M, Losier R, Doe K, Jackman P, Lee HB, Pharmaceutically active compounds in Atlantic Canadian sewage treatment plant effluents and receiving waters and potential for environmental effects as measured by acute and chronic aquatic toxicity. Environ Toxicol Chem 2006; 25(8): 2163-2176.] respectively. Using EU directive 93/67/EEC the pharmaceuticals under investigation can be classified as toxic (gemfibrozil, ibuprofen and naproxen), harmful (carbamazepine, bezafibrate, sulfapyridine, oxytetracycline and novobiocin) and non-toxic (sulfamethoxazole, trimethoprim and caffeine) and their potential toxicity for the aquatic environment is discussed.     

Occurrence of seven artificial sweeteners in the aquatic environment and precipitation of Tianjin,China

Seventy water samples, including wastewaters, tap waters, fresh surface waters, coastal waters, groundwaters, and precipitation samples, from Tianjin, China, were analyzed for seven commonly used artificial sweeteners (ASs). The concentrations of the investigated ASs were generally in the order of wastewater treatment plant (WWTP) influent > WWTP effluent > surface water > tap water > groundwater ≈ precipitation, while the composition profiles of ASs varied in different waters. Acesulfame, sucralose, cyclamate, and saccharin were consistently detected in surface waters and ranged from 50 ng/L to 0.12 mg/L, while acesulfame was the dominant AS in surface and tap waters. Aspartame was found in all of the surface waters at a concentration up to 0.21 μg/L, but was not found in groundwaters and tap waters. Neotame and neohesperidin dihydrochalcone were less frequently detected and the concentrations were low. The concentrations of the ASs in some of the surface waters were of the same order with those in the WWTP influents, but not with the effluents, indicating there are probably untreated discharges into the surface waters. The ASs were detected in precipitation samples with high frequency, and acesulfame, saccharin, and cyclamate were the predominant ASs, with concentrations ranging from 3.5 ng/L to 1.3 μg/L. A gross estimation revealed that precipitation may act as a source for saccharin and cyclamate in the surface environment of Tianjin city. Moreover, the presence of ASs in the atmosphere was primarily assessed by taking 4 air samples to evaluate their potential source in precipitation.     

Distributions of polycyclic aromatic hydrocarbons in surface waters, sediments and soils of Hangzhou City, China

Ten polycyclic aromatic hydrocarbons (PAHs) were simultaneously measured in 17 surface water samples and 11 sediments of four water bodies, and 3 soils near the water-body bank in Hangzhou, China in December 2002. It was observed that the sum of PAHs concentrations ranged from 0.989 to 9.663 microg/L in surface waters, from 132.7 to 7343 ng/g dry weight in sediments, and from 59.71 to 615.8 ng/g dry weight in soils. The composition pattern of PAHs by ring size in water, sediment and soil were surveyed. Three-ring PAHs were dominated in surface waters and soils, meanwhile sediments were mostly dominated by four-ring PAHs. Furthermore, PAHs apparent distribution coefficients (K(d)) and solid f(oc)-normalized K(d) (e.g. K(oc)= K(d) / f(oc)) were calculated. The relationship between logK(oc) and logK(ow) of PAHs for field data on sediments and predicted values were compared. The sources of PAHs in different water bodies were evaluated by comparison of K (oc) values in sediments of the river downstream with that in soils. Hangzhou section of the Great Canal was heavily polluted by PAHs released from industrial wastewater in the past and now PAHs in sediment may serve as sources of PAHs in surface water. PAHs in Qiantang River were contributed from soil runoff. Municipal road runoff was mostly contributed to West Lake PAHs.