Nonvolatile Organic Carbon Research Articles

Global Anthropogenic Emissions of Full-Volatility Organic Compounds.

Traditional global emission inventories classify primary organic emissions into nonvolatile organic carbon and volatile organic compounds (VOCs), excluding intermediate-volatility and semivolatile organic compounds (IVOCs and SVOCs, respectively), which are important precursors of secondary organic aerosols. This study establishes the first global anthropogenic full-volatility organic emission inventory with chemically speciated or volatility-binned emission factors. The emissions of extremely low/low-volatility organic compounds (xLVOCs), SVOCs, IVOCs, and VOCs in 2015 were 13.2, 10.1, 23.3, and 120.5 Mt, respectively. The full-volatility framework fills a gap of 18.5 Mt I/S/xLVOCs compared with the traditional framework. Volatile chemical products (VCPs), domestic combustion, and on-road transportation sources were dominant contributors to full-volatility emissions, accounting for 30, 30, and 12%, respectively. The VCP and on-road transportation sectors were the main contributors to IVOCs and VOCs. The key emitting regions included Africa, India, Southeast Asia, China, Europe, and the United States, among which China, Europe, and the United States emitted higher proportions of IVOCs and VOCs owing to the use of cleaner fuel in domestic combustion and more intense emissions from VCPs and on-road transportation activities. The findings contribute to a better understanding of the impact of organic emissions on global air pollution and climate change.

13C signatures of aerosol organic and elemental carbon from major combustion sources in China compared to worldwide estimates

Carbon isotope signatures are used to gain insight into sources and atmospheric processing of carbonaceous aerosols. Since elemental carbon (EC) is chemically stable, it is possible to apportion the main sources of EC (C3/C4 plant burning, coal combustion, and traffic emissions) using a dual 14C-13C isotope approach. The dual-isotope source apportionment crucially relies on accurate knowledge of 13C source signatures, which are seldom measured for EC. In this work, we present 13C signatures of organic carbon (OC) and EC for relevant sources in China. EC was isolated for 13C analysis based on the OC/EC split point of a thermal-optical method (EUSAAR_2 protocol). A series of sensitivity studies were conducted to investigate the EC separation and the relationship of the thermal-optical method to other EC isolation methods. Our results show that, first, the 13C signatures of raw materials and EC related to traffic emissions can be separated into three groups according to geographical location. Second, the 13C signature of OC emitted by the flaming combustion of C4 plants is strongly depleted in 13C compared to the source materials, and therefore EC is a better tracer for this source than total carbon (TC). A comprehensive literature review of 13C source signatures (of raw materials, of TC, and of EC isolated using a variety of thermal methods) was conducted. Accordingly, we recommend composite 13C source signatures of EC with uncertainties and detailed application conditions. Using these source signatures of EC in an example dual-isotope source apportionment study shows an improvement in precision. In addition, 13C signatures of OC were measured at three different desorption temperatures roughly corresponding to semi-volatile, low-volatile, and non-volatile OC fractions. Each source category shows a characteristic trend of 13C signatures with desorption temperature, which is likely related to different OC formation processes during combustion.

Formation of secondary organic carbon and cloud impact on carbonaceous aerosols at Mount Tai, North China

Abstract Carbonaceous aerosols measured at Mount Tai in north China in 2007 were further examined to study the formation of secondary organic carbon (SOC) and the impact of clouds on carbonaceous species. A constrained EC-tracer method and a multiple regression model showed excellent agreement in estimating SOC concentration. The average concentrations of non-volatile and semi-volatile SOC (SOCNV and SOCSV) were 2.61, 5.58 μg m−3 in spring and 2.81, 10.44 μg m−3 in summer. The total SOC accounted for 57.3% and 71.2% of total organic carbon in spring and summer, respectively, indicating the presence of high loading of secondary organic aerosol (SOA) in the North China Plain. The fraction of SOCNV increased with photochemical age (as indicated by NOx/NOy ratios) of air mass, whereas SOCSV was also influenced by the dynamic equilibrium between formation and sink. Significant scavenging by clouds of non-volatile organic carbon (OCNV) and elemental carbon (EC) was observed, whereas semi-volatile organic carbon (OCSV) concentrations increased during clouds, suggesting substantial SOA formation through aqueous-phase reactions in clouds. A mass balance model was proposed to quantify the scavenging coefficients for OCNV, EC and formation rates of OCSV in clouds. The scavenging coefficient constant of EC (KEC) varied from 0.11 to 0.90 h−1, and was higher than that of OCNV (KNV-OC: 0.07–0.55 h−1), implying internal mixing of EC with more hygroscopic species. The formation rate constant (JSV-OC) and sink constant (SSV-OC) of OCSV ranged from 0.09 to 1.39 h−1 and 0.001 to 1.07 h−1, respectively. These field derived parameters could be incorporated into atmospheric models to help close the gap between predicted and observed SOA loadings in the atmosphere.

Source and variation of carbonaceous aerosols at Mount Tai, North China: Results from a semi-continuous instrument

Abstract Carbonaceous aerosols were measured with a semi-continuous thermal-optical OC/EC analyzer at the summit of Mount Tai (1532.7 m a.s.l) in north China during spring and summer of 2007. Non-volatile organic carbon (NVOC) and elemental carbon (EC) showed high concentrations with mean values of 6.07, 1.77 and 5.05, 0.99 μg m −3 in spring and summer, respectively. The mean concentration of semi-volatile organic carbon (SVOC) was 6.26 μg m −3 in spring and 13.33 μg m −3 in summer, contributing 51 and 72% to total organic carbon (TOC), respectively. Different measurement methods for EC were compared, and a good agreement between optical and thermal methods was found. Due to volatilization of SVOC during sampling, the integrated filter measurement without denuder and backup absorbent tended to underestimate TOC compared to semi-continuous measurement. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) results indicated that the observed carbonaceous aerosols at Mount Tai were mostly contributed by the transport of aged aerosols in the planetary boundary layer (PBL) mixed with combined sources. Also, the influence of emissions from Korea was observed at Mount Tai, as well as biomass burning. Cloud processing contributed to elevated SVOC concentrations, and the formation of secondary organic aerosol (SOA) through photochemistry and cloud processing were both enhanced in summer. Clean air masses from the free troposphere reduced carbonaceous concentrations, and the regional background condition with 2.13 ± 1.05 μg m −3 of NVOC, 0.43 ± 0.29 μg m −3 of EC, and 2.40 to 6.80 μg m −3 of SVOC (for spring and summer, respectively) were suggested for the North China Plain.

Oligomer Content of α-Pinene Secondary Organic Aerosol

The quantity, extraction efficiency, and molecular composition of non-volatile oligomeric species in SOA generated by the reaction of α-pinene with ozone were studied. Two different methods of determining the total particulate mass in the reaction chamber were compared and found to be in good agreement when changes in the partitioning of semi-volatile compounds to the particle phase during measurement were properly handled. Almost all of the non-volatile organic carbon formed by the reaction was collected and recovered by extraction with organic solvents; recoveries with water extraction were somewhat lower. The identities of compounds extracted by the various solvents were determined using electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. Over 80% of the peaks weighted by mass and intensity were the same in the spectra of samples obtained from different extraction solvents. Standard addition plots were used to determine the amounts of two commercially available monomer compounds in the SOA extracts. When the response factors for those compounds were applied to other monomers detected in the mass spectra, the weight percent of monomers was estimated to be slightly less than 50%, with the remaining mass (over 50%) assigned to oligomers. The oligomer content is sufficiently large that it should be taken into account when modeling the formation and properties of laboratory SOA.

Modifications to the Sunset Laboratory Carbon Aerosol Monitor for the Simultaneous Measurement of PM2.5 Nonvolatile and Semi-Volatile Carbonaceous Material

Semi-volatile organic carbonaceous material (SVOC) in fine particles is not reliably measured with conventional semicontinuous carbon monitors because semi-volatile carbonaceous material is lost from the collection media during sample collection. Two modifications of a Sunset Laboratory carbon aerosol monitor allowing for the determination of semi-volatile fine particulate organic material are described. Collocated conventional and modified instruments were operated simultaneously using a common inlet. Comparisons were made with integrated PC-BOSS data for quartz filter retained nonvolatile organic carbon (NVOC) and elemental carbon (EC), SVOC, and total carbon (TC = SVOC + NVOC + EC) and good agreement was observed between TC concentrations during studies conducted in Rubidoux, CA. Precision of the comparison was σ=±1.5 μg-C/m3 (±8%). On the basis of experiments performed with the modified Sunset monitor, a dual-oven Sunset monitor was developed and extensively tested in Lindon, UT; Riverside, CA; and in environmental exposure chambers. The precision for the measurement of TC with the dual-oven instrument was σ = ±1.4 μg-C/m3 (±13%).

Semi-continuous mass closure of the major components of fine particulate matter in Riverside, CA

The application of newly developed semi-continuous aerosol monitors allows for the measurement of all the major species of PM 2.5 on a 1-h time basis. Temporal resolution of both non-volatile and semi-volatile species is possible. A suite of instruments to measure the major chemical species of PM 2.5 allows for semi-continuous mass closure. A newly developed dual-oven Sunset carbon monitor is used to measure non-volatile organic carbon, semi-volatile organic carbon and elemental carbon. Inorganic species, including sulfate and nitrate, can be measured with an ion chromatograph based sampler. Comparison of the sum of the major chemical species in an urban aerosol with mass measured by an FDMS resulted in excellent agreement. Linear regression analysis resulted in a zero-intercept slope of 0.98±0.01 with an R 2=0.86. One-hour temporal resolution of the major species of PM 2.5 may reduce the uncertainty in receptor based source apportionment modeling, will allow for better forecasting of PM 2.5 episodes, and may lead to increased understanding of related health effects.

New methods for the direct determination of dissolved inorganic, organic and total carbon in natural waters by Reagent-Free™ Ion Chromatography and inductively coupled plasma atomic emission spectrometry

New methods have been developed and applied successfully for the determination of dissolved inorganic, organic and total carbon in water samples. The new methods utilize two instrumental setups, Reagent-Free™ Ion Chromatography (RF™-IC) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Dissolved inorganic carbon (DIC) was measured in untreated samples along with Cl −, F − and SO 4 2− using RF™-IC and by in-line mixing with 0.1 M HNO 3 to enhance CO 2 removal in the nebulizer, followed by ICP-AES analysis. Total dissolved carbon (TDC) was measured by in-line mixing with 0.1 M NaOH following ICP-AES analysis. Dissolved organic carbon (DOC) was obtained as the difference between DIC and TDC. Only non-volatile organic carbon could be detected by the present method. The workable limits of detection obtained in the present study were 0.5 mM (RF™-IC) and 0.1 mM (ICP-AES) for dissolved inorganic and organic carbon, respectively. The power of the new methods lies in routine analysis of DIC and DOC in samples of natural waters of variable composition and salinity using analytical techniques and facilities available in most laboratories doing water sample analysis. The techniques are sensitive and precise, can be automated using gas-tight sample vials and auto-samplers, and are independent of most elemental interferences with the exception of chloride overload by saline samples when using RF™-IC. The new methods were successfully applied for analysis of DIC and DOC in selected samples of natural and synthetic waters.

The Measurement of Fine Particulate Semivolatile Material in

Ammonium nitrate and semivolatile organic material (SVOM) are significant components of fine particles in urban atmospheres. These components, however, are not properly determined with methods such as the fine particulate matter (PM2.5) Federal Reference Method (FRM) or other single filter samplers because of significant losses of semivolatile material (SVM) from particles collected on the filter during sampling. The R&P tapered element oscillating microbalance (TEOM) monitor also does not measure SVM, because this method heats the sample to remove particle bound water, which also results in evaporation of SVM. Recent advances in monitoring techniques have resulted in samplers for both integrated and continuous measurement of total PM2.5, including the particle concentrator Brigham Young University organic sampling system (PC-BOSS), the real time total ambient mass sampler (RAMS), and the R&P filter dynamics measurement system (FDMS) TEOM monitor. Results obtained using these samplers have been compared with those obtained with either a PM2.5 FRM sampler or a TEOM monitor in studies conducted during the past five years. These studies have shown the following: (1) the PC-BOSS, RAMS, and FDMS TEOM are all comparable. Each instrument measures both the nonvolatile material and the SVM. (2) The SVM is not retained on the heated filter of a regular TEOM monitor and is not measured by this sampling technique. (3) Much of the SVM is also lost during sampling from single filter samplers such as the PM2.5 FRM sampler. (4) The amount of SVM lost from single filter samplers can vary from less than one-third of that lost from heated TEOM filters during cold winter conditions to essentially all during warm summer conditions. (5) SVOM can only be reliably collected using an appropriate denuder sampler. (6) A PM2.5 speciation sampler can be easily modified to a denuder sampler with filters that can be analyzed for semivolatile organic carbon (OC), nonvolatile OC, and elemental carbon using existing OC/elemental carbon analytical techniques. The research upon which these statements are based for various urban studies are summarized in this paper.

Oxygen‐Enhanced Biodegradation of Phenoxy Acids in Ground Water at Contaminated Sites

The effects of adding oxygen to anaerobic aquifer materials on biodegradation of phenoxy acid herbicides were studied by laboratory experiments with aquifer material from two contaminated sites (a former agricultural machinery service and an old landfill). At both sites, the primary pollutants were phenoxy acids and related chlorophenols. It was found that addition of oxygen enhanced degradation of the six original phenoxy acids and six original chlorophenols. Inverse modeling on 14C 4-chloro-2-methylphenoxypropanoic acid (MCPP) degradation curves revealed that increasing the oxygen concentrations from <0.3 mg/L up to 7 to 8 mg/L shortened the lag phases (from approximately 150 d to 5 to 25 d) and increased first-order degradation rate constants by 1 order of magnitude (from approximately 5 x 10(-2) d(-1) to up to 30 x 10(-2) d(-1)). Additionally, the degree of MCPP mineralization was increased (30% to 50% mineralized at low oxygen concentrations and 50% to 70% mineralized at high oxygen concentrations, based on 14CO2 recovery). These positive effects on degradation were observed even at relatively low oxygen concentrations (2 mg/L). Furthermore, effects related to the addition of oxygen on the general geochemistry were studied. An oxygen consumption of 2.2 to 2.6 mg O2/g dw was observed due to oxidation of solid organic matter and, to some extent (0.5% to 11% of the total oxygen consumption), water-soluble compounds such as Fe2+, dissolved Mn, nonvolatile organic carbon, and NH4+. Overall, the results suggest that stimulated biodegradation by addition of oxygen might be a feasible remediation technology at herbicide-contaminated sites, although oxygen consumption by the sediment could limit the applicability.

Natural attenuation of xenobiotic organic compounds in a landfill leachate plume (Vejen, Denmark)

Demonstration of natural attenuation of xenobiotic organic compounds (XOCs) in landfill leachate plumes is a difficult task and still an emerging discipline within groundwater remediation. One of the early studies was made at the Vejen Landfill in Denmark in the late 1980s, which suggested that natural attenuation of XOCs took place under strongly anaerobic conditions within the first 150 m of the leachate plume. This paper reports on a revisit to the same plume 10 years later. Within the strongly anaerobic part of the plume, 49 groundwater samples were characterized with respect to redox-sensitive species and XOCs. The analytical procedures have been developed further and more compounds and lower detection limits were observed this time. In addition, the samples were screened for degradation intermediates and for toxicity. The plume showed fairly stationary features over the 10-year period except that the XOC level as well as the level of chloride and nonvolatile organic carbon (NVOC) in the plume had decreased somewhat. Most of the compounds studied were subject to degradation in addition to dilution. Exceptions were benzene, the herbicide Mecoprop (MCPP), and NVOC. In the early study, NVOC seemed to degrade in the first part of the plume, but this was no longer the case. Benzyl succinic acid (BSA) was for the first time identified in a leachate plume as a direct indicator, and as the only intermediate of toluene degradation. Toxicity measurements on solid phase-extracted (SPE) samples revealed that toxic compounds not analytically identified were still present in the plume, suggesting that toxicity measurements could be helpful in assessing natural attenuation in leachate plumes.

A System for the Direct Determination of the Nonvolatile Organic Carbon, Dissolved Organic Carbon, and Inorganic Carbon in Water Samples through Inductively Coupled Plasma Atomic Emission Spectrometry

A new system has been developed for the determination of total organic carbon (TOC) and inorganic carbon (IC) or total inorganic carbon (TIC) in waters. Only nonvolatile organic compounds can be detected through the present method. The system presented in this work is based on the measurement of the carbon atomic emission intensity in inductively coupled plasma atomic emission spectrometry (ICP-AES). This way, the organic matter does not undergo any preoxidation step. A semiautomatic accessory connected to the spectrometer separates the different carbon fractions (i.e., organic and inorganic). Because most of the solutions used in the present work did not contain suspended solid particles, the actual parameter that was determined was the dissolved organic carbon (DOC). The present system exhibits good sensitivities compared to those provided by conventional TOC and IC determination methods. The limits of detection obtained in the present work have been 0.07 and 0.0007 mg/L C in terms of TOC and IC, respectively. Furthermore, the system is able to handle high-salt-content solutions. This fact suggests that it would be possible to analyze seawater samples, avoiding some of the problems encountered with conventional methods, such as system blocking or interferences. The TOC and IC values found for natural samples are very close to those measured using conventional methods. The ICP-AES method has been successfully used in two interesting applications: (i) monitoring the efficiency of a water treatment plant and (ii) determining the contents of dissolved carbon dioxide, on one hand, and that of carbonate and bicarbonate, on the other, in the same sample.

PHASE PARTITIONING OF BLACK CARBON, NON-VOLATILE ORGANIC CARBON AND SOLUBLE INORGANIC SUBSTANCES BETWEEN THE DROPLET AND INTERSTITIAL PHASE OF CLOUDS AT MT. BROCKEN, GERMANY

PHASE PARTITIONING OF BLACK CARBON, NON-VOLATILE ORGANIC CARBON AND SOLUBLE INORGANIC SUBSTANCES BETWEEN THE DROPLET AND INTERSTITIAL PHASE OF CLOUDS AT MT. BROCKEN, GERMANY

Strontium-isotope studies of “brown water” (organic-rich groundwater) from Denmark

Groundwater from some Quaternary and upper Tertiary aquifers in western Jutland, Denmark, is heavily influenced by "brown water", i.e., groundwater with a high content of naturally occurring dissolved organic matter. Stable-isotope analyses (18O/16O and D/H) indicate that both Quaternary and upper Tertiary aquifers are dominated by meteoric water. However, strontium-isotope analyses make it possible to distinguish between water samples from Quaternary and Miocene aquifers. Relatively low 87Sr/86Sr ratios, i.e., ∼0.7083, in Sr-rich water samples indicate that the majority of dissolved Sr in groundwater from Miocene as well as Quaternary strata is probably derived from Miocene marine skeletal carbonate matter in the subsurface. This situation is probably the result of Quaternary glacial reworking of upper Tertiary material and/or hydraulic contact between Quaternary and Miocene aquifers. A positive correlation between Sr contents and non-volatile organic carbon indicates that the remarkably high contents of organic matter recorded in these aquifers almost certainly are derived from Miocene sources as well.

Fine Particulate Organic Material in the Los Angeles Basin - I: Assessment of the High-Volume Brigham Young University Organic Sampling System, BIG BOSS

ABSTRACT A multi-system, high-volume, parallel plate diffusion dénuder Brigham Young University Organic Sampling System (BIG BOSS) was tested using collocated samplers at the Pico Rivera Monitoring Station of the South Coast Air Quality Management District, South Coast Air Basin, in September 1994. Six-hr daytime and 9-hr nighttime samples were collected with a flow of about 200 L/min through each of the three systems designed to collect particles smaller than 2.5, 0.8, and 0.4 mm in a diffusion denuder sampler. Efficiency for the removal of gas phase organic compounds by the diffusion denuder was evaluated using both theoretical predictions and field measurements. Both measured and calculated data indicate high denuder efficiency for the removal of gas phase aromatic and paraffinic compounds. The precision of the BIG BOSS was evaluated using collocated samplers. The precision of determination of total carbon and elemental carbon retained by a quartz filter or of semi-volatile carbonaceous material lost from particles during sampling averaged ±7%. The precision of determination of individual organic compounds averaged ±10%. An average of 42 and 62% of the particulate organic material was semi-volatile organic compounds (SVOCs) lost from particles during sampling for daytime and nighttime samples, respectively. This “negative” sampling artifact was an order of magnitude larger than the “positive” quartz filter artifact due to adsorption of gas phase organic material. Daytime concentrations of fine particulate elemental carbon and nonvolatile organic carbon were higher than nighttime concentrations, but nighttime fine particles contained more semi-volatile organic material than daytime.

Determination of Nonvolatile Organic Carbon in Aquifer Solids After Carbonate Removal by Sulfurous Acid

AbstractThe precise determination of total organic carbon (TOC) in aquifer materials is important in the estimation of retardation coefficients for organic compound transport. Commonly used methods for TOC determination after carbonate removal by acidification include: weight loss on ignition of solids at 550° C, acid‐dichromate oxidation, and combustion at 800–950° C. Since carbonate carbon frequently is more abundant than organic carbon all TOC methods depend on efficient and complete carbonate removal prior to the TOC quantification step. A method for the determination of TOC in aquifer solids involving carbonate removal by 0.73 M sulfurous acid and subsequent combustion at 800° C was tested on solids from three aquifers and on mineral standards. The carbon quantification by combustion and infrared detection of CO2 was accurate at solid organic carbon contents between 30 and 10,000 μgC/g. The acid treatment added small amounts of carbon to the sample, and siderite removal was incomplete. For samples without siderite or dolomite, the accuracy of TOC determinations was enhanced by grinding the solids. Measurement of very low TOC contents (50–100 /μgC/g) requires supplementary testing of grinding and acid treatment effects.

Distribution of Organic Compounds from Municipal Solid Waste in the Groundwater Downgradient of a Landfill (Grindsted, Denmark)

The distribution of organic compounds in the leachate plume downgradient of the Grindsted Landfill was mapped along two 300 m long transects (285 groundwater samples). At the border of the landfill, elevated concentrations of dissolved organic matter 30-110 mg of C L -1 (measured as nonvolatile organic carbon, NVOC) were found. In a distance of 130 m downgradient of the landfill, the NVOC had decreased to background level, which is 1-3 mg of C L -1 . More than 15 organic compounds were identified in the groundwater at the downgradient border of the landfill with benzene, toluene, ethylbenzene, and xylenes as dominating. No pesticides were identified, but some phenoxy acids, which could be metabolites of known pesticides, were found. In a distance of approximately 60 m from the landfill, most of the specific organic compounds were no longer detectable. Since dilution and sorption apparently cannot account for the disappearance of the specific organic compounds within the first 60 m of the plume, it is proposed that the majority of the specific organic compounds were degraded in the anaerobic plume under methanogenic/sulfate-reducing or iron-reducing conditions. The investigation indicates that the aquifer has a substantial natural attenuation capacity

Interlaboratory study of a method for determining nonvolatile organic carbon in aquifer materials

The organic carbon fraction in aquifer mate- rials exerts a major influence on the subsurface mobilities of organic and organic-associated contaminants. The spa- tial distribution of total organic carbon (TOC) in aquifer materials must be determined before the transport of hy- drophobic organic pollutants in aquifers can be modeled accurately. Previous interlaboratory studies showed that it is difficult to measure TOC concentrations 1%. We have tested a new analytical method designed to improve the accuracy and precision of nonvolatile TOC quantitation in geologic materials that also contain carbonate minerals. Four authentic aquifer materials and one NIST standard reference material were selected as test materials for a blind collaborative study. Nonvolatile TOC in these materials ranged from 0.05 to 1.4%, while TIC ranged from 0.46 to 12.6%. Sample rep- licates were digested with sulfurous acid, dried at 40~ and then combusted at 950~ using LECO or UIC instru- ments. For the three test materials that contained >2% TIC, incomplete acidification resulted in a systematic

Fate of organic contaminants in the redox zones of a landfill leachate pollution plume (Vejen, Denmark)

Samples from 75 sample locations in a landfill leachate pollution plume reveal a significant disappearance of specific organic compounds (SOC's) within the first 100 m of the plume. Only the herbicide Mecoprop® (MCPP) migrates further. Since sorption and dilution cannot account for the decreasing concentrations, degradation is considered to be the governing process. Non-volatile organic carbon shows a corresponding fate probably acting as a substrate for the microbial processes. The first 20 m of the plume are methanogenic/sulfidogenic, judged on the chemistry of the groundwater, followed by a significant ferrogenic zone exhibiting a substantial capacity to degrade the SOC's. The presence of intermediary products (here an oxidized camphor compound) supports the concept of degradation within the ferrogenic zone. This investigation draws the attention to the significant natural attenuation of organic contaminants and to the so far neglected ferrogenic zone in controlling the fate of organic contaminants in leachate plumes.

Evolution de l'azote kjeldahl et de la biomasse bacterienne le long d'une filiere de traitement d'eau potable

Evolution de l'azote kjeldahl et de la biomasse bacterienne le long d'une filiere de traitement d'eau potable