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Contaminant transport through a single hole in a geomembrane (GM) that forms part of composite liner with a geosynthetic clay liner (GCL) for applied heads (0.3 and 1 m) and an applied pressure of about 100 kPa is modeled and compared with experimental results. The system was first permeated with distilled water until a steady state was reached. The permeant was then switched to an NaCl solution. The inferred interface transmissivity at steady state (after 280 days) is about 2.3 x [10.sup.-11] [m.sup.2]/s for both heads examined. After 800 days permeation with an 0.14 mol/L NaCl solution, the interface transmissivity between the geomembrane and GCL was inferred to have decreased from 2.3 x [10.sup.-11] to 1.1 x [10.sup.-11] [m.sup.2]/s for experiments with heads of both 0.3 and 1 m. Modeling of the flow and changes in the GCL hydraulic conductivity arising from interaction between the bentonite and the 0.14 mol/L NaCl permeant is shown to give excellent agreement with the observed leakage. The differences between modeling a uniform and nonuniform interface transmissivity is found to be small--with the leakage being dominated by the interface transmissivity 0.1 to 0.15 m from the hole in the GM. Typical published values for the diffusion coefficient for both the GCL and sandy soil are shown to give good predictions of effluent concentration with time and chloride distribution in the silty sand in contact with the composite liners at the end of the test. Key words: numerical modeling, leakage, composite liner, geosynthetic clay liner, advection, transport, landfill. Cet article presente la modelisation du transport de contaminants a travers un trou unique dans de la geomembrane (GM) faisant partie d'un revetement composite avec argile et geosynthetique (GCL) pour des tetes appliquees (0,3 et 1 m) et des pressions appliquees d'environ 100 kPa. Les resultats de la modelisation sont ensuite compares a des resultats experimentaux. Le systeme est d'abord infiltre avec de l'eau distillee jusqu'a ce que le regime permanent soit atteint. Ensuite, le liquide permeant est change par une solution de NaCl. La transmissivite inferee a l'interface en regime permanent (apres 280 jours) est d'environ 2,3 x [10.sup.-11] [m.sup.2]/s pour les deux tetes testees. Apres 800 jours de permeation avec une solution de 0,14 mol/L NaCl, la transmissivite de l'interface entre la geomembrane et le GCL est supposee avoir diminue de 2,3 x [10.sup.-11] [m.sup.2]/s a 1,1 x [10.sup.-11] [m.sup.2]/s pour les essais avec des tetes de 0,3 et de 1 m. La modelisation de l'ecoulement et des variations de conductivite hydraulique du GCL survenant en reponse aux interactions entre la bentonite et la solution de 0,14 mol/L NaCl demontre des correspondances excellentes avec les fuites observees. Les differences entre la modelisation d'une transmissivite a l'interface uniforme ou non uniforme s'averent etre faibles, les fuites etant dominees par la transmissivite a 0,1 m et 0,15 m du trou dans la GM. Des valeurs typiques publiees du coefficient de diffusion autant pour le GCL que pour le sol sablonneux permettent d'obtenir des bonnes predictions de la concentration a l'effluent avec le temps et de la distribution du chlorure dans le sable silteux en contact avec les revetements composites a la fin de l' essai. Mots-cles : modelisation numerique, fuite, revetement composite, revetement d'argile et geosynthetique, advection, transport, site d' enfouissement. [Traduit par la Redaction], Introduction Composite liners used at the base of modern landfills often involve a high-density polyethylene (HDPE) geomembrane (GM) over a geosynthetic clay liner (GCL). The primary role of the GCL [...]

A promising photolysis based technology to dechlorinate polychlorinated biphenyls (PCBs), extracted from soils, in alkaline isopropanol (IPA) as reaction medium has been proposed. To be marketable the impact of co-contaminants extracted along with the PCBs, on the photodechiorination process needs investigation. In this paper the effectiveness of the photodeclorination process on PCBs extracted from samples of a representative soil containing co-contaminants is reported. The pholodechl ori nation or PCBs extracted from weathered soils showed promising results of more than 76% dechlorination within the first hour of UV irradiation. Nearly complete dechlorination (96%) was achieved after 2 h of UV irradiation. To provide quantitative controlled appraisal of the effect of co-contaminants and explanation of the effects, dechlorination of neat Aroclor 1254 in the presence of the common co-contaminant, transformer oil, was evaluated. Further, the effect of transformer oil on some of the individual PCB congeners in the Aroclor mixture was also studied. The difference in the maximum percentage dechlorination of PCBs with and without transformer oil is 15%. Key words: PCBs, extraction, dechlorination, 2-propanol, transformer oil, co-contaminants. Une technologie prometteuse basee sur la photolyse est proposee pour dechlorer les BPC extraits des sols dans un milieu de reaction compose d'alcool isopropylique alcalin. Afin d'etre commercialisable, il faut examiner l'impact des co-contaminants extraits avec les BPC lors du processus de photo-dechloration. Dans eel article, l'efficacite du processus de photo-dechloralion sur les BPC extraits d'echantillons d'un sol representatif contenant des co-contaminants est presentee. La photo-chloration des BPC extrails de sols alleres a monlre des resultals de dechloraiion prometteurs de plus de 76% dans la premiere heure de rayonnement UV. Une dechloration presque complete (96 %) a ete realisee apres 2 heures de rayonnement UV. Pour fournir une evaluation quantitative controlee de l'effet des co-contaminants et I'explication des effets. la dechloration d'Aroclor 1254 pur en presence du co-contaminant commun, de l'huile de transformateur, a ete evaluee. De plus, l'effet de l'huile de transformateur sur certains des congeneres individuels des BPC dans le melange d'Aroclor a egalement ete etudie. La difference dans le pourcentage maximum de dechloration des BPC avec et sans huile de transformateur est de 15%. Mots-cles: BPC. extraction, dechloration. alcool isopropylique. huile de transformateur, co-contaminants. [Traduit par la Redaction], Introduction Recent successes on the dechlorination of polychlorinated biphenyls (PCBs) using UV, has opened possibilities of applying this technique to remediate PCB contaminated soils and sediments. The dechlorination of PCBs [...]

Buildup/wash-off (BUWO) models are widely used to estimate pollutant export from urban and suburban watersheds. Here, we propose that the mass of washed-off particulate during a storm event is insensitive to the time between storm events (the traditional predictor of particulate accumulation in BUWO models). Our analysis employed USGS data of total suspended solids and discharge data for nonsnow events in a 9.4-[km.sup.2] suburban catchment in Madison, Wis. Kinetic energy of rainfall was calculated using National Weather Service NEXRAD radar reflectivity. A regression analysis found that storm event runoff volume and rainfall kinetic energy explained 81% of the variability in event particulate load; volume alone explained 69% of the variability in event loads. Time between storm events was not significant. Additionally, we simulated storm event particulate loads using a BUWO model and a model assuming a constant mass available for wash-off. Both models produced very similar predictions over a range of parameterizations, suggesting that buildup models could perhaps be simplified under many circumstances. DOI: 10.1061/(ASCE)EE.1943-7870.0000142 CE Database subject headings: Watersheds; Water pollution; Surface water: Stormwater management; Urban areas; Wisconsin; Catchments. Author keywords: Nonpoint source pollution; Urban hydrology; Buildup/wash-off models; Nexrad Levell II Data.

A proprietary storm-water treatment system (Baysaver 1/2 K) was monitored as part of a low impact development project to assess pollutant removal efficiency and to model removal as a function of flow rate, season, and dry time. Twenty six storm events were sampled over a 12-month period and analyzed for total suspended solids, turbidity, conductivity, ammonia/ammonium, nitrate/nitrite, total phosphorus, total Zn, total Pb, and total Cu. The data were analyzed to determine which parameters showed significant removal by the device and whether or not the removal efficiencies were influenced by peak flow rate, season of the year, and/or dry time. Results indicated that the removal of each pollutant analyzed was statistically significant with the exception of conductivity, which showed higher outflow levels resulting in significant release of ions. Regression analyses revealed that all pollutants except for conductivity and total phosphorus showed significant negative relationships to peak flow rate and that conductivity and total Cu reductions were significantly related to the season of the year. DOI: 10.1061/(ASCE)0733-9372(2009) 135:7(511) CE Database subject headings: Stormwater management; Water treatment; Peak flow; Sustainable development; Pollutant; Flow rates.

This paper presents the first membrane inlet method that can be used together with field portable mass spectrometers for the analysis of semivolatile pharmaceuticals (pethidine, benzophenone, and cocaine) and environmental pollutants (terbutryne and butylated hydroxyl toluene (BHT)) dissolved in organic micro extracts. A microliter of the organic extract is simply injected into a closed hot cell membrane inlet (hc-MIMS), and an electron ionization mass spectrum of the vaporized semivolatile sample molecules can be recorded shortly thereafter. Detection limits at low picomole quantities or low/sub ng/[micro]L concentrations in the extract are demonstrated for solutes in methanol, ethanol, acetone, and toluene. A linear correlation between analyte concentration and signal was found in the range of 1-100 ng/[micro]L, and the relative standard deviation (RSD) was approximately 10%. As a practical example we demonstrate the detection of cocaine in extracts from dried coca leaves. The analysis of organic micro extracts using hc-MIMS represents a considerable extension of the type and complexity of analytes that can be measured using a field portable MIMS system, since it does not require special and field tedious modifications to the standard MIMS system.

This paper describes an enhanced liquid chromatography--mass spectrometry (LC-MS) strategy for the analysis of a selected group of 56 organic pollutants in wastewater. This group comprises 38 pharmaceuticals and 10 of their most frequent metabolites, 6 pesticides, and 2 disinfectants. The LC-MS methodology applied is based in the use of a hybrid triple-quadrupole linear ion trap mass spectrometer (QTRAP) in combination with time-of-flight mass spectrometry (TOF-MS). The join application of both techniques provided very good results in terms of accurate quantification and unequivocal confirmation. Quantification was performed by LC-QTRAP-MS operating under selected reaction monitoring (SRM) mode in both positive and negative electrospray ionization. Unequivocal identification was provided by the acquisition of three SRM transitions per compound in most of the cases and by LC-TOF-MS analysis, which allows obtaining accurate mass measurements of the identified compounds with errors lower than 2 ppm. Additionally, the use of TOF-MS permits retrospective analysis, since the full spectrum is recorded at all times with a high sensitivity. Thus, review of recorded chromatograms looking for new compounds or transformation products suspected to be present in the samples is feasible allowing one to increase the scope of the method along the monitoring program. The analytical performance of the quantitative LC-QTRAP-MS method was evaluated in effluent wastewater samples. Linearity of response over 3 orders of magnitude was demonstrated for most compounds ([R.sup.2] > 0.99). Method limits of detection were between 0.04 and 50 ng [L.sup.-1]. Finally, the methodology was successfully applied to a monitoring study intended to characterize wastewater effluents of six sewage treatment plants in Spain. The presence of most of compounds was detected at concentrations ranging from 9 ng [L.sup.-1] (atrazine) to 15 [micro]g [L.sup.-1] (paraxanthine).

Small, volatile hydrocarbons, including trichloroethylene, vinyl chloride, carbon tetrachloride, benzene, and chloroform, are common environmental pollutants that pose serious health effects. We have developed transgenic poplar (Populus tremula x Populus alba) plants with greatly increased rates of metabolism and removal of these pollutants through the overexpression of cytochrome P450 2E1, a key enzyme in the metabolism of a variety of halogenated compounds. The transgenic poplar plants exhibited increased removal rates of these pollutants from hydroponic solution. When the plants were exposed to gaseous trichloroethylene, chloroform, and benzene, they also demonstrated superior removal of the pollutants from the air. In view of their large size and extensive root systems, these transgenic poplars may provide the means to effectively remediate sites contaminated with a variety of pollutants at much faster rates and at lower costs than can be achieved with current conventional techniques. CYP2E1 | P4SO | poplar | trichloroethylene | carbon tetrachloride