Presence Of Organic Micropollutants Research Articles

Sulfamethoxazole is Metabolized and Mineralized at Extremely Low Concentrations.

The presence of organic micropollutants in water and sediments motivates investigation of their biotransformation at environmentally low concentrations, usually in the range of μg L-1. Many are biotransformed by cometabolic mechanisms; however, there is scarce information concerning their direct metabolization in this concentration range. Threshold concentrations for microbial assimilation have been reported in both pure and mixed cultures from different origins. The literature suggests a range value for bacterial growth of 1-100 μg L-1 for isolated aerobic heterotrophs in the presence of a single substrate. We aimed to investigate, as a model case, the threshold level for sulfamethoxazole (SMX) metabolization in pure cultures of Microbacterium strain BR1. Previous research with this strain has covered the milligram L-1 range. In this study, acclimated cultures were exposed to concentrations from 0.1 to 25 μg L-1 of 14C-labeled SMX, and the 14C-CO2 produced was trapped and quantified over 24 h. Interestingly, SMX removal was rapid, with 98% removed within 2 h. In contrast, mineralization was slower, with a consistent percentage of 60.0 ± 0.7% found at all concentrations. Mineralization rates increased with rising concentrations. Therefore, this study shows that bacteria are capable of the direct metabolization of organic micropollutants at extremely low concentrations (sub μg L-1).

Interfacial engineering of BiVO4/PANI p-n heterojunction for enhanced photocatalytic degradation of p-nitrophenol: Pathway, toxicity evaluation and mechanistic insights

The presence of organic micro-pollutants (OMPs) in the water sources is a major threat to the aquatic and human health and also affects the wastewater treatment process. p-Nitrophenol (p-NP), has been extensively used as raw materials in various chemical industries. The present study focused on the development of BiVO4/PANI nanocomposites (NCs) for enhanced photocatalytic degradation of p-NP under visible light irradiation. The morphology, chemical composition and crystallinity of the prepared NCs was characterized by XRD, XPS, FE-SEM, RAMAN, EIS and TEM, and the optical properties of the NCs were determined by UV–vis DRS, and PL analysis. Compared to the bare BiVO4 and PANI, the NCs showed a better performance against p-NP (98.25 %) and had good cycle stability (91.91 % after six cycles). The enhance photocatalytic performance of the NCs is ascribed to the synergistic effect and the p-n heterojunction formed between BiVO4 and PANI. Furthermore, several tests were done to determine the effect of pH, NCs and p-NP concentrations and influence of various ions were also studied. Scavenger experiments revealed that •OH, and h+ contributed significantly in the degradation process of p-NP. The intermediate metabolites were identified, and toxicity of the by-products was elucidated by using GC–MS and ECOSAR program respectively. The reusability of the material was assessed by repeating the degradation experiment for 6 consecutive cycles. This work underlines the promising potential of BiVO4/PANI NCs for efficient treatment of toxic pollutants bearing wastewater.

LED-driven photo-Fenton process for micropollutant removal by nanostructured magnetite anchored in mesoporous silica

The presence of organic micropollutants in water bodies represents a threat to living organisms and ecosystems due to their toxicological effects and recalcitrance in conventional wastewater treatments. In this context, the application of heterogeneous photo-Fenton based on magnetite nanoparticles supported on mesoporous silica (SBA15) is proposed to carry out the non-specific degradation of the model compounds ibuprofen, carbamazepine, hormones, bisphenol A and the dye ProcionRed®. The operating conditions (i.e., pH, catalyst load and hydrogen peroxide concentration) were optimized by Response Surface Methodology (RSM). The paramagnetic properties of the nanocatalysts allowed their repeated use in sequential batch operations with catalyst losses below 1%. The feasibility of the process was demonstrated as removal rates above 90% after twelve accomplished after twelve consecutive cycles. In addition, the contributions of different reactive oxygen species, mainly •OH, were analyzed together with the formation of by-products, achieving total mineralization values of 15% on average.

Ferrate(VI)/Periodate System: Synergistic and Rapid Oxidation of Micropollutants via Periodate/Iodate-Modulated Fe(IV)/Fe(V) Intermediates.

The presence of organic micropollutants in water sources worldwide has created a need for the development of effective and selective oxidation methods in complex water matrices. This study is the first report of the combination of ferrate(VI) (Fe(VI)) and periodate (PI) for synergistic, rapid, and selective elimination of multiple micropollutants. This combined system was found to outperform other Fe(VI)/oxidant systems (e.g., H2O2, peroxydisulfate, and peroxymonosulfate) in rapid water decontamination. Scavenging, probing, and electron spin resonance experiments showed that high-valent Fe(IV)/Fe(V) intermediates, rather than hydroxyl radicals, superoxide radicals, singlet oxygen, and iodyl radicals, played a dominant role in the process. Further, the generation of Fe(IV)/Fe(V) was evidenced directly by the 57Fe Mössbauer spectroscopic test. Surprisingly, the reactivity of PI toward Fe(VI) is rather low (0.8223 M-1 s-1) at pH 8.0, implying that PI was not acting as an activator. Besides, as the only iodine sink of PI, iodate also played an enhanced role in micropollutant abatement by Fe(VI) oxidation. Further experiments proved that PI and/or iodate might function as the Fe(IV)/Fe(V) ligands, causing the utilization efficiency of Fe(IV)/Fe(V) intermediates for pollutant oxidation to outcompete their auto-decomposition. Finally, the oxidized products and plausible transformation pathways of three different micropollutants by single Fe(VI) and Fe(VI)/PI oxidation were characterized and elucidated. Overall, this study proposed a novel selective oxidation strategy (i.e., Fe(VI)/PI system) that could efficiently eliminate water micropollutants and clarified the unexpected interactions between PI/iodate and Fe(VI) for accelerated oxidation.

Photo-electrocatalytic based removal of acetaminophen: Application of visible light driven heterojunction based BiVO4/BiOI photoanode

The presence of organic micro-pollutants (OMPs) in wastewater treatment effluents is becoming a major threat to the water safety for aquatic and human health. Photo-electrocatalytic based advanced oxidation process (AOP) is one of the emerging and effective techniques to degrade OMPs through oxidative mechanism. This study investigated the application of heterojunction based BiVO4/BiOI photoanode for acetaminophen (40 μg L−1) removal in demineralized water. Photoanodes were fabricated by electrodeposition of BiVO4 and BiOI photocatalytic layers. Optical (UV–vis diffusive reflectance spectroscopy), structural (XRD, SEM, EDX) and opto-electronic (IPCE) characterization confirmed the successful formation of heterojunction for enhanced charge separation efficiency. The heterojunction photoanode showed incident photon to current conversion efficiency of 16% (λmax = 390 nm) at an external voltage of 1 V under AM 1.5 standard illumination. The application of the BiVO4/BiOI photoanode in the removal of acetaminophen at 1 V (external bias) vs Ag/AgCl under simulated sunlight showed 87% removal efficiency within the first 120 min compared to 66% removal efficiency of the BiVO4 photoanode. Similarly, combining BiVO4 and BiOI exhibited 57% increase in first order removal rate coefficient compared to BiVO4. The photoanodes also showed moderate stability and reusability by showing 26% decrease in overall degradation efficiency after three cycles of each 5 h experiment. The results obtained in this study can be considered as a stepping stone towards the effective removal of acetaminophen as an OMP present in wastewater.

Influence of biofilm thickness on the removal of thirteen different organic micropollutants via a Membrane Aerated Biofilm Reactor (MABR)

The presence of organic micropollutants (OMPs) in natural water bodies has become an emerging concern due to their fast dissemination into natural water sources, high persistence, ubiquitous nature, and detrimental impact on the environment and human health. This study evaluated the Membrane Aerated Biofilm Reactor (MABR) efficiency in the removal of 13 OMPs commonly reported in water. Results demonstrated that OMPs removal is dependent on biofilm thickness and bacterial cell density, microbial community composition and physicochemical properties of OMPs. Effective removals of ammonium and organic carbon (COD, >50%), acetaminophen (70%) and triclosan (99%) were obtained even at early stages of biofilm development (thickness < 0.33 mm, 2.9 ×105 cell mL−1). An increase in biofilm thickness and cell density (1.02 mm, 2.2 ×106 cell mL−1) enhanced the system performance. MABR achieved over 90% removal of nonpolar, hydrophobic and hydrophilic OMPs and 22–69% removal of negatively charged and acidic OMPs. Relative abundances of Zoogloea, Aquabacterium, Leucobacter, Runella, and Paludilbaculum bacteria correlated with the removal of certain OMPs. In addition, MABR achieved up to 96% nitrification and 80% overall COD removal by the end of the experiment. The findings from this study demonstrated MABRs to be a feasible option to treat municipal wastewater polluted by OMPs.

Mutagenicity, health risk, and disease burden of exposure to organic micropollutants in water from a drinking water treatment plant in the Yangtze River Delta, China

A wide variety of organic micropollutants in drinking water pose a serious threat to human health. This study was aimed to reveal the characteristics of organic micropollution profiles in water from a drinking water treatment plant (DWTP) in the Yangtze River Delta, China and investigate the mutagenicity, health risk and disease burden through mixed exposure to micropollutants in water. The presence of organic micropollutants in seven categories in organic extracts (OEs) of water from the DWTP was determined, and Ames test was conducted to test the mutagenic effect of OEs. Meanwhile, health risk of exposure to organic micropollutants in finished water through three exposure routes (ingestion, dermal absorption and inhalation) was assessed with the method proposed by U.S. EPA, and disability-adjusted life years (DALYs) were combined to estimate the disease burden of cancer based on the carcinogenic risk (CR) assessment. The results showed that 28 organic micropollutants were detected in the raw and finished water at total concentrations of 967.28 ng/L and 1073.45 ng/L, respectively, of which phthalate esters (PAEs) were the dominant category (95.79% in the raw water and 96.61% in the finished water). Although the results of the Ames test for OEs were negative and the non-carcinogenic hazard index of the organic micropollutants in the finished water was less than 1 in all age groups, the total CR was 2.17 × 10−5, higher than the negligible risk level (1.00 × 10−6). The total DALYs caused by the organic micropollutants in the finished water was 2945.59 person-years, and the average individual DALYs was 2.21 × 10−6 per person-year (ppy), which was 2.21 times the reference risk level (1.00 × 10−6 ppy) defined by the WHO. Exposure to nitrosamines (NAms) was the major contributor to the total CR (92.06%) and average individual DALYs (94.58%). This study demonstrated that despite the negative result of the mutagenicity test with TA98 and TA100 strains, the health risk of exposure to organic micropollutants in drinking water should not be neglected.

Occurrence, distribution and removal of organic micro-pollutants in a low saline water body

A low saline backwater canal, mainly utilized for domestic and agricultural purposes, has been analyzed for the possible presence of organic micropollutants (OMP) and their potential removal was explored by multilayered microfiltration membranes. The qualitative as well as quantitative analysis were carried out for a span of one year using the technique of liquid chromatography connected with high resolution mass spectrometry (LC-Q-TOF-MS). The identification of the formally unknown compounds was initially done using non-target analysis based on the mass accuracy, isotopic pattern and MS/MS spectral interpretation. Results of the non target screening revealed the presence of 11 OMPs. Five of these OMPs were confirmed using standards; these include chlorophene (CHP), oxybenzone (OXY), N, N-diethyl-meta-toluamide (DEET), N, N-diethyl-benzamide (DEB) and dibutyl phthalate (DBP). Among the confirmed OMPs, the highest concentration was observed for DBP (244.61 ng l−1). The most frequently observed OMP in the study area was DBP while the least was DEB which is an insect repellent as well as a degradation product of DEET. The ecological risk associated with the target compounds has also been analyzed by calculating the risk quotient (RQ) and the results revealed that at the detected levels, these compounds are capable of causing low to medium risk. Low pressure (<0.3 bar) filtrations of the compounds were attempted using microfiltration (MF) and, poly(ethyleneimine)/poly(styrene sulfonate) (PEI/PSS) multi-layered MF membrane for spiked ultrapure water and also for natural water from the back-water canal. The batch mode illustrates nearly complete removal of CHP and OXY in spiked solutions and a good removal efficiency from natural water. The effect of coexisting ions and surfactants in feed is also illustrated. The high efficiency of the removal of both CHP and OXY, in such a complex medium highlights the potential application of the present method for the removal of similar OMPs in natural waters.

Effect of organic micropollutants on biofouling in a forward osmosis process integrating seawater desalination and wastewater reclamation

This study systematically investigated the effect of organic micropollutants (OMPs) on biofouling in forward osmosis (FO) integrating wastewater treatment and seawater dilution. Synthetic seawater (0.6 M sodium chloride) was used as a draw solution and synthetic municipal wastewater as a feed solution. To evaluate the impact of OMPs in a replicate parallel study, wastewater was supplemented with a mixture of 7 OMPs (OMPs-feed) and without OMPs (control) during 8 batch filtration cycles with feed and draw solution replacement after each filtration. The FO performance (water flux), development and microbial composition properties of biofilm layers on the wastewater side of the FO membrane were studied. Compared to the control without OMPs, the FO fed with OMPs containing wastewater showed (i) initially the same water flux and flux decline during the first filtration cycle, (ii) with increasing filtration cycle a lower flux decline and (iii) lower concentrations for the total cells, ATP, EPS carbohydrates and proteins in biofilm layers, and (iv) a lower diversity of the biofilm microbial community composition (indicating selective pressure) and (v) increasing rejection of 6 of the 7 OMPs. In essence, biofouling on the FO membrane showed (i) a lower flux decline in the presence of OMPs in the feed water and (ii) a higher OMPs rejection, both illustrating better membrane performance. This study has a significant implication for optimizing osmotic dilution in terms of FO operation and OMPs rejection.

Removal of Organic Micropollutants in Wastewater Treated by Activated Sludge and Constructed Wetlands: A Comparative Study

The aim of this study is to compare the removal of organic micropollutants (OMPs) in wastewater by activated sludge (AS) and constructed wetlands (CWs). This analysis was carried out in a wastewater treatment plant (WWTP) of a rural community where they implemented two technologies in parallel: AS and a pilot plant of horizontal subsurface flow (HSSF) constructed wetlands. In this case, these systems were fed by the same influent and the removal efficiencies of 14 OMPs, including analgesics/anti-inflammatories, anticonvulsants, stimulants, antifungals, fragrances, plasticizers, and transformation products, were evaluated in each system. Regarding the presence of OMPs in the wastewater, the concentrations of these compounds in the influent ranged from 0.16 to 7.75 µg/L. In general, the removal efficiencies achieved by the AS system were between 10%–95% higher than those values reported by HSSFs with values above 80% for naproxen, ibuprofen, diclofenac, caffeine, triclosan, methyl dihydrojasmonate, bisphenol-A, 2-hydroxyl ibuprofen, and carboxy ibuprofen (p &lt; 0.05). This behavior can be related to the aerobic conditions that promote the AS system with oxidation-reduction potential (ORP) and dissolved oxygen (DO) values above −281 mV and 0.24 mg/L, respectively. However, the removal of galaxolide was greater in HSSF system than in AS with significant difference of 70% (p &lt; 0.05). Despite these results, this study reveals that comparing both technologies, AS had the best removal performance of these OMPs studied.

Investigation into Micropollutant Removal from Wastewaters by a Membrane Bioreactor.

Direct potable reuse of wastewater is attractive as the demand for potable water increases. However, the presence of organic micropollutants in industrial and domestic wastewater is a major health and environmental concern. Conventional wastewater treatment processes are not designed to remove these compounds. Further many of these emerging pollutants are not regulated. Membrane bioreactor based biological wastewater treatment has recently become a preferred method for treating municipal and other industrial wastewaters. Here the removal of five selected micropollutants representing different classes of emerging micropollutants has been investigated using a membrane bioreactor. Acetaminophen, amoxicillin, atrazine, estrone, and triclosan were spiked into wastewaters obtained from a local wastewater treatment facility prior to introduction to the membrane bioreactor containing both anoxic and aerobic tanks. Removal of these compounds by adsorption and biological degradation was determined for both the anoxic and aerobic processes. The removal as a function of operating time was investigated. The results obtained here suggest that removal may be related to the chemical structure of the micropollutants.

Encapsulation of triclosan within 2-hydroxypropyl–β–cyclodextrin cavity and its application in the chemisorption of rhodamine B dye

Presence of organic micro-pollutants in aquatic ecosystems is a major concern in public health. Designing effective strategies to remove organic pollutants are subject of intense research interests. Rhodamine B (Rb), a widely used stain in textile, food industries and biomedical laboratories, is highly cytotoxic and induce oxidative stress, hormonal imbalance and apoptosis. Thus devising an effective strategy for Rb removal from aquatic environment is an urgent need. Present study demonstrates the applicability of triclosan (TR)-2-hydroxypropyl–β–cyclodextrin (HP–β–CD) inclusion complex to effectively adsorb rhodamine B (Rb) from aqueous solution. Triclosan readily incorporates into HP–β–CD cavity and the calculated binding constant is 230.5 M−1. Both solid and solution state complexes have been prepared and detailed characterization have been carried out using fluorescence spectroscopy, MALDI–TOF, FT–IR, 1H NMR, XRD, FT-Raman and SEM methods. The TR:HP–β–CD complex exhibits excellent ability to remove Rb from aqueous solutions with maximum adsorption efficiency of 261.78 mg/g. The adsorption process is a pseudo-second order reaction. Adsorption isotherm analysis reveals that the isotherm data are well fitted to the Langmuir adsorption model. Details of the isotherm analysis reveal that the adsorption take place at specific homogeneous sites where the adsorbent forming monolayer coverage of Rb at the surface of the TR:HP–β–CD complex.

Constructed wetland microcosms for the removal of organic micropollutants from freshwater aquaculture effluents

The presence of organic micropollutants (MPs) in the aquatic environment is strongly related to their difficult elimination by conventional water and wastewater treatment processes. Therefore, alternative treatment technologies are required to overcome this problem. In this domain, constructed wetlands (CWs) have gained increasing attention in the last years, mainly due to the low-cost, simple operation/maintenance and environmental friendliness of these systems. However, studies on the application of CWs to remove MPs from freshwater aquaculture effluents are still scarce. In this work, planted (Phragmites australis) vertical subsurface flow CWs, at microcosm scale, were investigated for the removal of MPs found in non-spiked freshwater aquaculture effluents, namely atrazine, isoproturon, perfluorooctanesulfonic acid (PFOS), clarithromycin, erythromycin, fluoxetine, norfluoxetine, and 2-ethylhexyl-4-methoxycinnamate (EHMC). A wider multi-component set of 36 MPs was also studied by adding these MPs at 100 ng L−1 to the same matrix (alachlor, atrazine, chlorfenvinphos, isoproturon, PFOS, azithromycin, clarithromycin, erythromycin, diclofenac, methiocarb, acetamiprid, clothianidin, thiacloprid, thiamethoxam, EHMC, simazine, atorvastatin, bezafibrate, carbamazepine, cephalexin, ceftiofur, citalopram, clindamycin, clofibric acid, diphenhydramine, enrofloxacin, fluoxetine, ketoprofen, metoprolol, norfluoxetine, ofloxacin, propranolol, tramadol, trimethoprim, venlafaxine, and warfarin). High weekly removal efficiencies (>87%) were observed for all MPs in both non-spiked and spiked experiments, with the exception of EHMC (removal rates between 0 and 86%). These results emphasize the potential of CWs to remove MPs from freshwater aquaculture effluents, but also the need to enhance the performance of these systems for the elimination of some recalcitrant MPs, such as EHMC, which was found at high concentrations in the studied effluents.

Degrading Organic Micropollutants: The Next Challenge in the Evolution of Biological Wastewater Treatment Processes

Global water scarcity is driving the need for identifying new water source. Wastewater could be a potential water resource if appropriate treatment technologies could be developed. One of the barriers to obtaining high quality water from wastewater arises from the presence of organic micropollutants, which are biologically active at trace levels. Removal of these compounds from wastewater by current physico-chemical technologies is prohibitively expensive. While biological treatment processes are comparatively cheap, current systems are not capable of degrading the wide range of organic micropollutants present in wastewater. As current wastewater treatment processes were developed for treating conventional pollutants present at mg/L levels, degrading the ng/L levels of micropollutants will require a different approach to system design and operation. In this paper we discuss strategies that could be employed to develop biological wastewater treatment systems capable of degrading organic micropollutants.

Organic micropollutants (OMPs) in natural waters: Oxidation by UV/H2O2 treatment and toxicity assessment

Organic micropollutants (OMPs) are ubiquitous in natural waters even in places where the human activity is limited. The presence of OMPs in natural water sources for human consumption encourages the evaluation of different water purification technologies to ensure water quality. In this study, the Biobío river (Chile) was selected since the watershed includes urban settlements and economic activities (i.e. agriculture, forestry) that incorporate a variety of OMPs into the aquatic environment, such as pesticides, pharmaceuticals and personal care products. Atrazine (herbicide), caffeine (psychotropic), diclofenac (anti-inflammatory) and triclosan (antimicrobial) in Biobío river water and in different stages of a drinking and two wastewater treatment plants downstream Biobío river were determined using solid phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC-MS/MS) and electrospray ionization (ESI). Quantification of these four compounds showed concentrations in the range of 8 ± 2 to 55 ± 10 ng L−1 in Biobío river water, 11 ± 2 to 74 ± 21 ng L−1 in the drinking water treatment plant, and 60 ± 10 to 15,000 ± 1300 ng L−1 in the wastewater treatment plants. Caffeine was used as an indicator of wastewater discharges.Because conventional water treatment technologies are not designed to eliminate some emerging organic pollutants, alternative treatment processes, UV and UV/H2O2, were employed. The transformation of atrazine, carbamazepine (antiepileptic), diclofenac and triclosan was investigated at laboratory scale. Both processes were tested at different UV doses and the Biobío river water matrix effects were evaluated. Initial H2O2 concentration used was 10 mg L−1. Results showed that, the transformation profile obtained using UV/H2O2 at UV doses up to 900 mJ cm−2, followed the trend of diclofenac > triclosan > atrazine > carbamazepine. Furthermore acute toxicity tests with Daphnia magna were carried out after UV/H2O2 treatments of the OMPs mixture studied. At the lower UV doses tested (300 mJ cm−2) a higher toxicity was observed, suggesting the formation of toxic intermediates in the course of the reaction. As expected, at higher UV doses the toxicity declined. Considering the treatment of the mixture of ATZ, CBZ, DCL and TCS with a UV dose of 1200 mJ cm−2 and 10 mg L−1 of H2O2 the acute toxicity results exhibits values for Daphnia magna immobilization equal to 20 and 42% evaluated after 24 and 48 h, respectively.

COMPARATIVE STUDIES ON ELIMINATION OF ESTROGENS AND XENOESTROGENS BY THE OXIDATION PROCESSES

The presence of organic micropollutants, especially the substances interfering with hormonal processes termed as endocrine disrupting chemicals EDCs, in surface waters is a potential threat to life and living organisms, including humans. Hazardous biological activity of these compounds (including toxicity) and high resistance to biodegradation necessitate research on their removal in conventional and non-con- ventional water treatment and wastewater treatment processes. The presented research was motivated by the increasingly frequent reports in the literature regarding the effectiveness of different advanced oxidation processes used for the elimination of micropollutants. In the present study the degradation efficiency for 17-estradiol (E2), 17-ethinylestradiol (EE2) and bisphenol A (BPA) in the photolysis process (UV) and in the coupled photolysis and ozonation process (UV/O3) was evaluated in real and artificial municipal wastewater treatment plant effluent. The obtained results were compared for the degradation efficiency of the test compounds in deionised water. It was determined that both the use of the UV and UV/O3 processes enabled to achieve high degradation efficiencies for 17-estradiol and 17-ethinylestradiol regardless of the treated solution. Degradation of the compounds in the processes occurred in a very short time. On the other hand, the efficiency of elimination of bisphenol A depended on the applied process and the physico-chemical composition of the solution. It was shown that the combination of photolysis with ozonation allowed achieving higher degree of degradation of the test compound than in the case of a single UV process. The study allowed also the identification of substances supporting the degradation of bisphenol A in the UV-O3 process.

Appropriate drinking water treatment processes for organic micropollutants removal based on experimental and model studies — A multi-criteria analysis study

The presence of organic micropollutants (OMPs), pharmaceuticals and personal care products (PPCPs) in potable water is of great environmental and public health concern. OMPs are included in the priority list of contaminants in United States EPA and European framework directives. Advanced treatment processes such as reverse osmosis, nanofiltration, ozonation and adsorption are the usual industry-recommended processes for OMPs removal, however, natural systems, e.g., riverbank filtration and constructed wetlands, are also potentially efficient options for OMPs removal. In this study, a decision support system (DSS) based on multi-criteria analysis (MCA) was created to compare processes for OMPs removal under various criteria. Multi-criteria analysis (MCA), a transparent and reliable procedure, was adopted. Models were built for both experimental and predicted percent-removals for a range of OMPs reflecting different physicochemical properties. The experimental percent-removals for several processes (riverbank filtration (RBF), ozonation, advanced oxidation, adsorption, reverse osmosis, and nanofiltration) were considered. The predicted percent-removals were taken from validated quantitative structure activity relationship (QSAR) models. Analytical methods to detect OMPs in water are very laborious, thus a modeling approach such as QSAR is an attractive option.A survey among two groups of participants including academics (PhD students and post-doctoral research associates) and industry (managers and operators) representatives was conducted to assign weights for the following criteria: treatability, costs, technical considerations, sustainability and time. The process rankings varied depending on the contaminant species and personal preferences (weights). The results indicated that RBF and oxidation were preferable over adsorption and membranes processes. The results also suggest that the use of a hybrid treatment process, e.g., combining a natural system with an advanced treatment (oxidation) process, may provide benefits for OMPs removal.The proposed DSS can be used as a screening tool for experimental planning or a feasibility study preceding the main treatment system selection and design. It can also be considered as an aid in assessing a multi-barrier approach to remove OMPs.

Multivariate Exploratory Data Analysis of the Organic Micropollutants Found in the Llobregat River (Catalonia, Spain)

The presence of organic micropollutants in the Llobregat River (Catalonia, Spain) has been investigated and the results interpreted by Principal Component Analysis (PCA). A deeper insight into the interpretation of the results was achieved by the extension of this analysis of the same samples including general water quality analytical parameters such as: total organic carbon, oxidability, biochemical oxygen demand after 5 days, dissolved oxygen, pH, suspended solids, anionic surfactants, total hydrocarbons, ammonia, nitrates, phenol index and total coliforms. PCA afforded the exploration of the main pollution sources of the Llobregat River as well as the characterization of the geographical and temporal distribution of these pollution sources.

On the presence of PCDD/Fs and other chlorinated hydrocarbons in the second generation of the European Reference Soil Set--the EUROSOILS.

The second generation of the European Reference Soil-Set, the so-called EUROSOILS, has been introduced recently. The presence of organic micro-pollutants in this new type of reference materials has already been studied for polycyclic aromatic hydrocarbons, triazines, phenylureas and other pesticides. The already large amount of data concerning the level of different contaminants, the elemental composition and matrix properties is completed by a survey by means of GC/MS on the polychlorinated dibenzodioxins/furans (PCDD/Fs) and other chlorinated hydrocarbons. Higher concentrations for 4,4'-DDT in EUROSOIL 2 (10.57 +/- 0.02 ng/g), for dieldrin in EUROSOIL 3 (8.85 +/- 0.87 ng/g) and for heptachlor-epoxide in EUROSOIL 4 (5.86 +/- 0.16 ng/g) could be detected. Sum concentrations for PCDD/Fs were 15.02 ng/kg (EUROSOIL 1), 214.29 ng/kg (EUROSOIL 2), 873.32 ng/kg (EUROSOIL 3), 54.47 ng/kg (EUROSOIL 4) and 119.61 ng/kg (EUROSOIL 5).

The determination of polychlorinated biphenyls in municipal sewage sludges using microwave-assisted extraction and gas chromatography-mass spectrometry

The presence of organic micropollutants [such as poly(chlorobiphenyls)] in municipal sewage sludges is a major problem on account of risks associated with the agricultural valorisation of the sludges. In France, since January 1998, maximum values for trace organic pollutants are imposed [0.8 mg kg–1 dry matter for the sum of seven poly(chlorobiphenyls)]. The aim of this study was to develop a reliable, accurate and fast analytical procedure (extraction, clean-up, quantification) in order to determine polychlorinated biphenyls in municipal sewage sludges. Such pollutants could be efficiently extracted from dried sewage sludge samples using microwave-assisted extraction. This technique affords several advantages as compared to the classical Soxhlet extraction, mainly rapidity and reduction in solvent consumption. Extractions (10 min under 30 W with 30 ml hexane–acetone 1:1) were conducted in the presence of copper to avoid sulfur interferences in the extracts. The latter were further concentrated and purified onto disposable silica cartridges. After final concentration and addition of the internal standard, they were analysed by gas chromatography coupled to mass spectrometry (in the selected ion monitoring mode). Two types of sludges (from Acheres and Valenton sewage treatment plants near Paris, France) were analysed, whose polychlorobiphenyl concentrations differed largely (Acheres sludge being the most contaminated). The microwave extraction compared favourably with the classical Soxhlet extraction. In addition, the sludge concentrations found with our experimental procedure were close to the analyses made by another laboratory, even though some discrepancy was noted.