Trace Organic Constituents Research Articles

Nontargeted Analysis of Trace Organic Constituents in Reverse Osmosis and UV-AOP Product Waters of a Potable Reuse Facility

To evaluate the ultraviolet (UV) advanced oxidation process (AOP) in a potable reuse facility, we characterized organic compounds in upstream reverse osmosis (RO)-treated recycled municipal wastewater samples collected before and after UV/H2O2 AOP by implementing nontargeted analysis (NTA) based on comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry. Five sampling events were conducted at an advanced water purification facility. Fewer compounds were found consistently in the UV-AOP product water (UVP) than the corresponding feedwater (RO permeate (ROP)): on average, 28 compounds (by quality control criteria) in ROP vs 10 in UVP. On average, 80% of the qualified compounds were tentatively identified by mass spectral comparison with the NIST EI library, followed by a 87.5% verification success rate with standards for 24 selected compounds. Halogenated acetonitriles were most frequently found in UVP. Six compounds found in UVP were also present in tested tap water. Only one of the compounds, bromodichloromethane, has a regulatory limit in drinking water. This exploratory study concluded that, in the context of potable water reuse, NTA was useful for identifying contaminants without a priori knowledge of their occurrence and that the UV/H2O2 AOP effectively removed trace organics that persisted in the ROP.

From urban dust and marine sediment to Ginkgo biloba and human serum-a top ten list of Standard Reference Materials (SRMs).

During the past 40years, the National Institute of Standards and Technology (NIST) has developed over 180 natural matrix Standard Reference Materials® (SRMs) for the determination of trace organic constituents in environmental, clinical, food, and dietary supplement matrices. A list of the Top Ten SRMs intended for organic analysis was identified based on selection criteria including analytical challenge to assign certified values, challenges in material preparation, novel matrices, longevity, widespread use, and unique design concept or intended use. The environmental matrix SRMs include air particulate matter, marine sediment, mussel tissue, and human serum with the focus on contaminants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated pesticides, and polybrominated diphenyl ethers (PBDEs). Human serum and plasma SRMs for clinical diagnostic markers including vitamin D metabolites represent clinical analysis, whereas infant formula, multivitamin/multielement tablets, and Ginkgo biloba constitute the food and dietary supplement matrices on the list. Each of the SRMs on the Top Ten list is discussed relative to the selection criteria and significance of the material, and several overall lessons learned are summarized.

Organic extracts from African dust storms stimulate oxidative stress and induce inflammatory responses in human lung cells through Nrf2 but not NF-κB

The health impact of the global African dust event (ADE) phenomenon in the Caribbean has been vaguely investigated. Heavy metals in ADE and non-ADE extracts were evaluated for the formation of reactive oxygen species (ROS) and antioxidant capacity by cells using, deferoxamine mesylate (DF) and N-acetyl-l-cysteine (NAC). Results show that ADE particulate matter 2.5 (PM2.5) induces ROS and stimulates oxidative stress. Pre-treatment with DF reduces ROS in ADE and Non-ADE extracts and in lung cells demonstrating that heavy metals are of utmost importance. Glutathione-S-transferase and Heme Oxygenase 1 mRNA levels are induced with ADE PM and reduced by DF and NAC. ADE extracts induced Nrf2 activity and IL-8 mRNA levels significantly more than Non-ADE. NF-κB activity was not detected in any sample. Trace elements and organic constituents in ADE PM2.5 enrich the local environment load, inducing ROS formation and activating antioxidant-signaling pathways increasing pro-inflammatory mediator expressions in lung cells.

Characterization of hydraulic fracturing flowback water in Colorado: Implications for water treatment

A suite of analytical tools was applied to thoroughly analyze the chemical composition of an oil/gas well flowback water from the Denver–Julesburg (DJ) basin in Colorado, and the water quality data was translated to propose effective treatment solutions tailored to specific reuse goals. Analysis included bulk quality parameters, trace organic and inorganic constituents, and organic matter characterization. The flowback sample contained salts (TDS=22,500mg/L), metals (e.g., iron at 81.4mg/L) and high concentration of dissolved organic matter (DOC=590mgC/L). The organic matter comprised fracturing fluid additives such as surfactants (e.g., linear alkyl ethoxylates) and high levels of acetic acid (an additives' degradation product), indicating the anthropogenic impact on this wastewater. Based on the water quality results and preliminary treatability tests, the removal of suspended solids and iron by aeration/precipitation (and/or filtration) followed by disinfection was identified as appropriate for flowback recycling in future fracturing operations. In addition to these treatments, a biological treatment (to remove dissolved organic matter) followed by reverse osmosis desalination was determined to be necessary to attain water quality standards appropriate for other water reuse options (e.g., crop irrigation). The study provides a framework for evaluating site-specific hydraulic fracturing wastewaters, proposing a suite of analytical methods for characterization, and a process for guiding the choice of a tailored treatment approach.

Persistence of artificial sweeteners in a 15-year-old septic system plume

Summary Groundwater contamination from constituents such as NO 3 - , often occurs where multiple sources are present making source identification difficult. This study examines a suite of major ions and trace organic constituents within a well defined septic system plume in southern Ontario, Canada (Long Point site) for their potential use as wastewater tracers. The septic system has been operating for 20 years servicing a large, seasonal-use campground and tritium/helium age dating indicates that the 200 m long monitored section of the plume is about 15 years old. Four parameters are elevated along the entire length of the plume as follows; the mean electrical conductivity value (EC) in the distal plume zone is 926 μS/cm which is 74% of the mean value below the tile bed, Na+ (14.7 mg/L) is 43%, an artificial sweetener, acesulfame (12.1 μg/L) is 23% and Cl− (71.5 mg/L) is 137%. EC and Cl− appear to be affected by dispersive dilution with overlying background groundwater that has lower EC but has locally higher Cl− as result of the use of a dust suppressant (CaCl2) in the campground. Na+, in addition to advective dilution, could be depleted by weak adsorption. Acesulfame, in addition to the above processes could be influenced by increasing consumer use in recent years. Nonetheless, both Na+ and acesulfame remain elevated throughout the plume by factors of more than 100 and 1000 respectively compared to background levels, and are strong indicators of wastewater impact at this site. EC and Cl− are less useful because their contrast with background values is much less (EC) or because other sources are present (Cl−). Nutrients ( NO 3 - , NH 4 + , PO 4 3 - , K+) and pathogens (Escherichia coli) do not persist in the distal plume zone and are less useful as wastewater indicators here. The artificial sweetener, acesulfame, has persisted at high concentrations in the Long Point plume for at least 15 years (and this timing agrees with tritium/helium-3 dating) and this compound likely occurs at uniquely high concentrations in domestic wastewater. As such, it holds considerable promise as a powerful new tracer of wastewater impact in groundwater.

Removal of drugs of abuse from municipal wastewater using reverse osmosis membranes

Drugs of abuse are important emerging contaminants due to their presence in water bodies following incomplete removal in wastewater treatment. This poses a threat to drinking water sources and has led to concerns about possible health effects, both to wildlife, ecosystems and humans. In recent years, there has been growing interest in the incorporation of reverse osmosis (RO) and nanofiltration (NF) membrane technologies into existing municipal and industrial wastewater treatment facilities as a quaternary treatment option. By improving effectiveness of wastewater treatment, the exposure of firstly, nature and secondly, humans to these compounds can be minimized. It has been suggested that these membrane techniques are suitable for cost-effective desalination and the removal of a wide range of low-molecular-weight (LMW) trace organic constituents, including drugs of abuse. This paper presents the detailed results of a feasibility assessment study on the removal of selected drugs and metabolites from secondary treated waste-water. The study was carried out at a small scale RO pilot plant. Three different FILMTECTM brackish water membranes were used; low energy (LE) membrane, high rejection membrane (BW30) and extra fouling resistant membrane (XFR). The results show that RO membranes can reduce the amount of target compounds in the effluent water. The obtained mean rejection values for the three membranes and six monitoring campaigns were as follows: 74–83% (caffeine), 49–63% (nicotine), 94–96% (cotinine), 98–99% (codeine), 98% (norcodeine), 81% (METH), 57–64% (MDA), 93–96% (MDMA) and 47–57% (MDEA). No major differences were observed between the three different membranes. This indicates that the low energy RO membrane provides the same removal efficiency as the other two membranes, thus demonstrating the potential for a less energy intensive RO plant operation.

Laboratory Measurements of the Heterogeneous Oxidation of Condensed-Phase Organic Molecular Makers for Meat Cooking Emissions

Multiphase oxidation of trace organic constituents inside of complex atmospheric particles is not well understood. In this study, organic aerosol formed from flash-vaporized residual grease from meat cooking was exposed to atmospherically relevant ozone concentrations in a smog chamber for 4-6 h. Changes in particle composition were measured to determine reaction rates for important molecular markers used for source apportionment analysis (oleic acid, palmitoleic acid, and cholesterol). Results are also presented for palmitic and stearic acids and likely reaction products. To quantify oxidation rates over a range of atmospheric conditions, separate experiments were conducted at low and high relative humidity and using particles mixed with and without secondary organic aerosol. Although particle composition, relative humidity, and secondary organic aerosol all influence the reaction rates, the unsaturated compounds were rapidly oxidized in every experiment. At typical summertime conditions, palmitoleic acid, oleic acid and cholesterol are estimated to have a chemical lifetime of about one day. The experimentally determined reaction rates are used in conjunction with the chemical mass balance model to investigate the effects of aging on source apportionment estimates. The results highlight that assumptions regarding the photochemical stability of molecular markers can lead to substantial biases in predictions of receptor models.

Thermal neutron activation analysis of essential and trace elements and organic constituents in Trikatu: An ayurvedic formulation

Trikatu, an Ayurvedic formulation of three dried powder spices, ginger, black pepper and pipali in equal proportion is widely used to promote digestion, assimilation and bioavailibility of food. It works synergistically, and hence, is more effective than an equal amount of any of its three ingredients taken separately. Five different brands and its three constituents were analyzed for 31 elements by instrumental neutron activation analysis (INAA) using 5-minute and 6-hour thermal neutron irradiation followed by high-resolution J-ray spectrometry. Heavy toxic metals Cd, Ni and Pb determined by atomic absorption spectrometry (AAS) were found below permissible limits. Most elements in different brands vary in a narrow range. Ginger is particularly enriched in Ca, Fe, Mg and Mn whereas black pepper is enriched in Cr, Se, P and Zn. Cu/Zn shows linear relationship (r = 0.92) with Cu whereas Fe and Mn exhibit inverse correlation (r = –0.89) in different brands. Hydro distillation of pipali yielded an essential oil whereby 10 organic constituents were identified by GC-MS. Also barbituric and tannic acids were isolated from the aqueous methanolic extract of pipali.

Study of solar system planetary lightning with LOFAR

Radio signatures of lightning discharges have been detected by the Voyager spacecraft near Saturn and Uranus up to 40 MHz. Corresponding flux densities at the distance of the Earth are up to 1000 Jansky (Jy) for Saturn (⩾1 event per minute above 50 Jy, with 30–300 ms duration) and up to a few tens of Jansky for Uranus. Low Frequency ARray LOFAR will allow us to detect and monitor the lightning activity at these two planets. Imaging will allow us to locate lightning sources on Saturn's disk (even if with moderate accuracy), which could then be correlated to optical imaging of clouds. Such observations could provide new information on electrification processes, atmospheric dynamics, composition, and geographical and seasonal variations, compared to the Earth. In addition, lightning may play a role in the atmospheric chemistry, through the production of non-equilibrium trace organic constituents potentially important for biological processes. LOFAR observations can also help us to assess the existence of lightning at Neptune (marginally detected by Voyager), at Venus (where their existence is very controversial), and at Mars (possibly resulting from dust cloud charging). At Jupiter, low-altitude ionospheric layers of meteoritic origin and/or intrinsically long discharge duration seem to prevent the emission and escape of high-frequency radio waves associated with lightning. LOFAR thus presents good possibilities for the detection and study of solar system planetary lightning; we also discuss its relevance to bring new information on Terrestrial lightning-related upper atmosphere transient phenomena (sprites, TIPPs…). Instrumental constraints are outlined.

A microslot impactor for organic aerosol sampling

A microslot impactor has been designed with the objective of collecting large, concentrated samples suitable for chemical analysis of trace organic constituents. It employs a single slotted orifice per stage, with orifice widths as small as 0.1 mm. Using a relatively small pump (13 kg), five cutpoints from 0.1 to 3.5 μm are obtained at a flow rate of 361 min−1 (6 × 10−4 m3s−1). The microslot impactor operates with incompressible flow and minimal pressure drops for the upper four stages, and sonic flow through the last (fifth) stage. Measured cutpoints for the incompressible flow stages are somewhat higher than predicted, with critical Stokes numbers corresponding to 10 to 30% greater than theory.

Certification of a Frozen Mussel Tissue Standard Reference Material (SRM 1974a) for Trace Organic Constituents

NIST SRM 1974a, Organics in Mussel Tissue (Mytilus edulis), has been issued as a frozen tissue homogenate with certified mass fractions for 15 polycyclic aromatic hydrocarbons (PAHs), 20 polychlorinated biphenyl (PCB) congeners, and 7 chlorinated pesticides. Noncertified mass fractions are provided for an additional 18 PAHs, 4 PCB congeners, 4 chlorinated pesticides, 28 inorganic constituents, 16 aliphatic hydrocarbons, and methylmercury. The mass fractions for the measured PAHs range from approximately 1 μg/kg to 164 μg/kg dry mass while the mass fractions for the measured PCB congeners range from approximately 3 μg/kg to 150 μg/kg dry mass.

On the integrity of cross-flow filtration for collecting marine organic colloids

Abstract The application of cross-flow filtration (CFF) to separate organic colloids with their sorbed load from dissolved components in seawater has been tested. Investigations have aimed at deconvoluting and quantifying several aspects of seawater CFF integrity: organic carbon blanks, membrane interactions (for both organic colloids and trace organic constituents), and the effective filter cut-off. A dynamic feed, permeate, and retentate sampling protocol during regular CFF fractionation of coastal seawater organic carbon and macromolecular standards was used to gain diagnostic information about sampling integrity. The organic carbon blank of the membrane module was significant. Large amounts of low-C water were required to flush the system to attain acceptable levels in what appears to be a diffusion-limited conditioning process. Observed decreasing permeate flux as a function of concentration factor (CF) was shown to be directly correlated with CFF colloid-fouling. A series of experiments were performed with a set of standard macromolecules, added at realistic seawater concentrations, to distinguish colloidal losses to the membrane from breakthrough. It was found that large fractions of carbohydrate, proteinaceous, and synthetic amphiphilic macromolecules became associated with the Osmonics PT1 (polysulfone, nominal cut-off 1.0 kD; 1 kD = 1000 daltons) CFF all-glass-and-stainless-steel system while partitioning between the seawater suspension and the membrane slowly reached steady state. Without further losses to the membrane, the retention coefficients for the colloid standards were determined, and an inherent seawater colloidal suspension cut-off at ~ 50 kD was found. Comparisons with the membrane science literature and theoretical calculations are presented to rationalize the observed artifacts and to direct optimization schemes.

Preparation and analysis of a river sediment Standard Reference Material for the determination of trace organic constituents

A river sediment Standard Reference Material (SRM) has been prepared and analyzed for determination of the concentrations of trace organic constituents. SRM 1939, “Polychlorinated Biphenyls (PCBs) in River Sediment A”, has been certified for the concentrations of three PCB congeners using the results obtained from capillary column gas chromatography with electron capture detection (GC-ECD) and from multidimensional (dual column) capillary gas chromatography with mass spectrometric detection (MCGC-MSD). For SRM certification, two independent analytical procedures are usually required. If only one analytical technique is used or if the procedures are not independent, then the concentrations are reported as “noncertified or informational” values rather than “certified” values. Noncertified values for 14 additional PCB congeners and five chlorinated pesticides, determined by GC-ECD, are also reported as well as noncertified concentrations for five polycyclic aromatic hydrocarbons (PAHs), determined using gas chromatography with mass spectrometric detection (GC-MSD). SRM 1939 complements SRM 1941, “Organics in Marine Sediment”, since both materials have 12 PCB congeners, five PAHs and five chlorinated pesticides in common. However, the concentrations differ by an order of magnitude for PAHs, and from one to over two orders of magnitude for the PCB congeners and chlorinated pesticides.

Preparation and analysis of a frozen mussel tissue reference material for the determination of trace organic constituents

A new mussel tissue Standard Reference Material (SRM) has been prepared and analyzed for trace organic and inorganic constituents. SRM 1974 (Organics in Mussel Tissue (Mytilus edulis)) is a frozen mussel tissue homogenate that has been certified for the concentrations of nine polycyclic aromatic hydrocarbons (PAHs) from results obtained from gas chromatography-mass spectrometry and reversed-phase liquid chromatography with fluorescence detection. Noncertified concentrations for 19 additional PAHs are also reported. Gas chromatography with electron capture detection and gas chromatography with mass spectrometric detection were used to provide noncertified concentrations for 13 polychlorinated biphenyl congeners and 9 chlorinated pesticides. In addition to the organic contaminants, noncertified concentrations for 36 trace elements were determined primarily by instrumental neutron activation analysis. SRM 1974 is the first frozen tissue SRM for environmental measurements of organic and inorganic constituents.

Preparation and analysis of a marine sediment reference material for the determination of trace organic constituents

A new marine sediment Standard Reference Material (SRM) has been prepared and analyzed for the determination of trace organic constituents. SRM 1941, Organics in Marine Sediment, has been certified for concentrations of 11 PAHs using results obtained from gas chromatography (GC) with flame ionization detection, gas chromatography-mass spectrometry, and liquid chromatography with fluorescence detection. Non-certified values for 24 additional PAHs are also reported. GC with electron capture detection was used to provide non-certified concentrations for 15 PCB congeners and 7 chlorinated pesticides. In addition to the organic contaminants, concentrations of 32 major and trace elements were determined using neutron activation analysis, and the sulfur content was also determined using isotope dilution thermal ionization mass spectrometry.

III Advances in the analysis of trace organic constituents of the diet, with particular reference to mass spectrometry

III Advances in the analysis of trace organic constituents of the diet, with particular reference to mass spectrometry

V Sources and biogenesis of trace organic constituents of the diet

The first page of this article is displayed as the abstract.

Decomposition and alteration of organic compounds dissolved in seawater

The dissolved organic matter in seawater is grouped into two fractions which are defined as having greatly differing reactivities with respect to both chemical and biological decomposition. One fraction, which constitutes the bulk of the material, is extremely stable and inert and is only slowly degraded by either chemical or biological processes. The other fraction, which is composed of trace organic compounds derived from living organisms, contains components such as free amino acids which are rapidly degraded, probably by marine organisms which use these compounds as a food source. Conclusions about the cycle of organic compounds in seawater based on total organic carbon concentrations could thus be misleading, since pathways involving labile trace organic constituents would be completely obscured. Investigations of the distribution, concentration, and possible diagenetic reactions of specific organic compounds are necessary in order to elucidate the cycle of these compounds in the oceans.

Trace composition of human respiratory gas.

A multistage cryogenic trapping system was used to sample and concentrate trace organic constituents in human respiratory gas. Chemical analysis was conducted by gas chromatography and mass spectrometry. Respiratory compound identification and production rate data are given for eight human test subjects. This study reports on the use of the sampling technique to diagnose metabolic diseases and for application in the study of industrial exposure.

Portable Instruments Based on Flame Ionization Detectors for Analysis of Air for Trace Organic Constituents.

Portable Instruments Based on Flame Ionization Detectors for Analysis of Air for Trace Organic Constituents.