Halogenated Organic Compounds Research Articles

Simultaneous observation of concurrent two-dimensional carbon and chlorine/bromine isotope fractionations of halogenated organic compounds on gas chromatography

It has been reported that isotope fractionation can occur on gas chromatography (GC), yet little is known about concurrent dual-elements isotope fractionations on GC. Revelation of concurrent two-dimensional carbon and chlorine/bromine isotope fractionations of halogenated organic compounds (HOCs) on GC may be of important significance for compound-specific isotope analysis (CSIA). This study presents an in-depth investigation of the two-dimensional C and Cl/Br isotope fractionations of HOCs on GC using GC-double focus magnetic-sector high resolution mass spectrometry (GC-DFS-HRMS). The two-dimensional C and Cl/Br isotope fractionations of four organochlorines and four bromobenzenes on GC were simultaneously measured by GC-DFS-HRMS. The isotope fractionations were evaluated with isotope ratios, relative variations of isotope ratios (△hE) and isotope fractionation extents (ΛhE). All the HOCs exhibited significant inverse C and Cl/Br isotope fractionations, with Λ13C of 38.14‰–307.56‰, Λ37Cl of 59.60‰–146.85‰, and Λ81Br of 25.89‰–142.10‰. The isotope fractionations were significant in both ends of chromatographic peaks, while the isotope ratios in center retention-time segments were the closest to comprehensive isotope ratios in the whole peaks. Significant correlations between C isotope fractionation and Cl/Br isotope fractionation were observed, indicating that the isotope fractionations might have strong relationships and/or be dominated by similar factors. Relevant mechanisms for the two-dimensional C and Cl/Br isotope fractionations were tentatively proposed on basis of a modified two-film model and the theories related to zero point energy. The results of this study gains new insights into concurrent two-dimensional isotope fractionation behaviors of HOCs during physical processes, and are conducive to CSIA studies involving C, Cl and Br for obtaining high-quality data, particularly to dual-elements CSIA of C and Cl/Br.

Comprehensive Screening Links Halogenated Organic Compounds with Testosterone Levels in Male Delphinus delphis from the Southern California Bight.

While environmental pollutants have been associated with changes in endocrine health in cetaceans, efforts to link contaminant exposure with hormones have largely been limited to a list of known, targeted contaminants, overlooking minimally characterized or unknown compounds of emerging concern. To address this gap, we analyzed a suite of potential endocrine disrupting halogenated organic compounds (HOCs) in blubber from 16 male short-beaked common dolphins ( Delphinus delphis) with known maturity status collected from fishery bycatch in the Southern California Bight. We employed a suspect screening mass spectrometry-based method to investigate a wide range of HOCs that were previously observed in cetaceans from the same region. Potential endocrine effects were assessed through the measurement of blubber testosterone. We detected 167 HOCs, including 81 with known anthropogenic sources, 49 of unknown origin, and 37 with known natural sources. The sum of 11 anthropogenic and 4 unknown HOC classes were negatively correlated with blubber testosterone. Evidence suggests that elevated anthropogenic HOC load contributes to impaired testosterone production in mature male D. delphis. The application of this integrative analytical approach to cetacean contaminant analysis allows for inference of the biological consequences of accumulation of HOCs and prioritization of compounds for future environmental toxicology research.

Formularity: Software for Automated Formula Assignment of Natural and Other Organic Matter from Ultrahigh-Resolution Mass Spectra.

Ultrahigh resolution mass spectrometry, such as Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS), can resolve thousands of molecular ions in complex organic matrices. A Compound Identification Algorithm (CIA) was previously developed for automated elemental formula assignment for natural organic matter (NOM). In this work, we describe software Formularity with a user-friendly interface for CIA function and newly developed search function Isotopic Pattern Algorithm (IPA). While CIA assigns elemental formulas for compounds containing C, H, O, N, S, and P, IPA is capable of assigning formulas for compounds containing other elements. We used halogenated organic compounds (HOC), a chemical class that is ubiquitous in nature as well as anthropogenic systems, as an example to demonstrate the capability of Formularity with IPA. A HOC standard mix was used to evaluate the identification confidence of IPA. Tap water and HOC spike in Suwannee River NOM were used to assess HOC identification in complex environmental samples. Strategies for reconciliation of CIA and IPA assignments were discussed. Software and sample databases with documentation are freely available.

Nontargeted Screening of Halogenated Organic Compounds in Bottlenose Dolphins (Tursiops truncatus) from Rio de Janeiro, Brazil.

To catalog the diversity and abundance of halogenated organic compounds (HOCs) accumulating in high trophic marine species from the southwestern Atlantic Ocean, tissue from bottlenose dolphins (Tursiops truncatus) stranded or incidentally captured along the coast of Rio de Janeiro, Brazil, were analyzed by a nontargeted approach based on GC×GC/TOF-MS. A total of 158 individual HOCs from 32 different structural classes were detected in the blubber of 4 adult male T. truncatus. Nearly 90% of the detected compounds are not routinely monitored in the environment. DDT-related and mirex/dechlorane-related compounds were the most abundant classes of anthropogenic origin. Methoxy-brominated diphenyl ethers (MeO-BDEs) and chlorinated methyl- and dimethyl bipyrroles (MBPs and DMBPs) were the most abundant natural products. Reported for the first time in southwestern Atlantic cetaceans and in contrast to North American marine mammals, chlorinated MBPs and DMBPs were more abundant than their brominated and/or mixed halogenated counterparts. HOC profiles in coastal T. truncatus from Brazil and California revealed a distinct difference, with a higher abundance of MeO-BDEs, mirex/dechloranes and chlorinated bipyrroles in the Brazilian dolphins. Thirty-six percent of the detected HOCs had an unknown structure. These results suggest broad geographical differences in the patterns of bioaccumulative chemicals found in the marine environment and indicate the need to develop more complete catalogs of HOCs from various marine environments.

Relative roles of H-atom transfer and electron transfer in the debromination of polybrominated diphenyl ethers by palladized nanoscale zerovalent iron

The relative significance of H-atom transfer versus electron transfer in the dehalogenation of halogenated organic compounds (HOCs) in bimetallic systems has long been debated. In this study, we have investigated this question through the case study of the debromination of 2, 2′, 4, 4’-tetrabromodiphenyl ether (BDE-47). The debromination rates of isomer products of BDE-47 by palladized nano zero-valent iron (n-ZVI/Pd) in the same reactor were compared. The results confirmed a shift in the debromination pathway of BDE-47 when treated with unpalladized nano zero-valent iron (n-ZVI) vs. treatment with n-ZVI/Pd. Study showed that BDEs could be rapidly debrominated in a palladium-H2 system, and the debromination pathway in this system is the same as that in the n-ZVI/Pd system. These results suggest that the H-atom species adsorbed on the surface of palladium are responsible for the enhanced reaction rates and the shift of the debromination pathway in the n-ZVI/Pd system. The Mulliken charges, calculated with density functional theory, on bromine atoms of PBDEs were directly correlated with the susceptibility to the e-transfer pathway in the n-ZVI system and inversely correlated with the susceptibility to the H-transfer pathway in n-ZVI/Pd system. These experimentally verified correlations in BDE-47 permit the prediction of the dominant debromination pathway in other BDEs.

The Role of Supporting Electrolyte on the Electrocatalytic Reduction of Organic Halides on Nanostructured Silver Electrodes in Water

Over recent two decades, electrocatalytic reduction of halogenated organic compounds (HOCs) was successfully employed in electrosynthesis and abatement of environmental pollutants by their conversion to less harmful compounds [1, 2]. Halogenated organic compounds have been frequently used in industry and disposed into wastewater and air, despite their toxicity and suspected mutagenicity. Some of them, like chloroform, are also disinfection by-products commonly produced during the chlorination of water and wastewater. Due their refractoriness to typical oxidative water remediation techniques, HOCs became one of the most problematic group of pollutants. Electrocatalytic reduction was already proven as alternative, useful method of HOCs removal from organic solutions after prior water-based electrolyte exchange from aprotic medium. The scope of this study was to reduce HOCs in water environment/aqueous solutions and to examine the possibility of direct elimination of HOCs without a need for electrolyte change. The electrochemical reduction of organic halides in aprotic media generally proceeds via two-electron cleavage of the C–X bond, occurring at very negative potentials at non-catalytic electrode surfaces (e.g., glassy carbon), what is the biggest disadvantage of this process due to the high energy requirement. To shift the reduction threshold to less negative potentials and therefore lower the costs of the process, new materials with enhanced catalytic properties toward electrocatalytic reduction are intensively studied. Among them, silver attracted significant interest, due to the most powerful electrocatalytic properties toward reduction of a wide range of organic halides [3]. It is generally accepted that this effect is directly related with a strong affinity of halides to silver, by means of specific adsorption of halide atom to the Ag surface. It was reported in the literature that nanostructured silver particles exhibit similar or even better electrocatalytic properties toward reduction of HOCs than bulk Ag electrodes due to the increased surface to volume ratio [4, 5]. It is surprising that Ag nanowire arrays have only once been used as electrodes for electrocatalytic reduction of organic halides, namely chloropropane [6]. It is expected that silver nanowire array electrodes should exhibit at least similar or even better electrocatalytic properties as nanoparticles and offer better stability and efficiency. Therefore, the aim of this research was also to synthesize and investigate electrocatalytic behavior of nanostructured Ag electrodes with different morphologies, and compare the obtained results with a silver bulk electrode. The electrocatalytic measurements were performed in various supporting electrolytes in order to select the optimum one and assess its influence on the mechanism of electrocatalytic reduction of chloroform. The two-step anodization process in oxalic acid (H2C2O4) was used in order to obtain highly ordered anodic aluminum oxide (AAO) membranes that served as templates for the synthesis of silver nanowire arrays. The electrochemical anodization of aluminum is a cost-effective method that results in hexagonally arranged nanopores. The barrier layer at the pore bottoms was removed by using a potential-shock method that results in AAO membranes with through-hole pores. Then, a thin layer of Ag was sputter deposited, and finally, the electrodeposition of Ag nanostructures was carried out in a commercially available silver plating solution by applying a constant current density. The electrocatalytic properties of nanostructured Ag electrodes were investigated by various voltammetric techniques in aqueous solutions of several different supporting electrolytes, such as NaOH, KClO4, NaClO4, and NaH2PO4.

A visible colorimetric sensor based on nanoporous polypropylene fiber membranes for the determination of trihalomethanes in treated drinking water

Water is an integral part of our society, and it is of the utmost importance that this water is clean and safe for potable use. Drinking water sources can become contaminated with halogenated organic compounds (HOCs) via improper disposal of refrigeration or air conditioning units, industrial usage, and even through the disinfection of our drinking water (chlorination). One class of these HOCs regulated by the U.S. Environmental Protection Agency (USEPA) is trihalomethanes (THMs). THMs have been found to cause adverse health effects and can even be carcinogenic, they are limited to 80ppb in treated water by the USEPA. Currently THM concentrations are detected in treated water using expensive analytical equipment, which have high sensitivity, but lack any portability or ease-of-use. Here we show a syndiotactic polypropylene (sPP) nanoporous electrospun fiber membrane capable of visible colorimetric detection of trihalomethanes (THMs) at environmentally relevant levels (ppb-scale), without a separate preconcentration step. The developed detection method includes a two-fold preconcentration technique coupled with a colorimetric detection reaction, integrated into a single sensor device. Here, the utilization of the colorimetric Fujiwara reaction serves as the detection reaction. This long-studied reaction has a response that is normally limited to a beaker scale visible detection range on the order of 80ppm THMs, when a separate preconcentration step is not present. The two-fold integrated preconcentration technique consists of a thermodynamic method based on the utilization of the THM: water equilibrium in the vapor phase of the system as well as a physical method using a sPP nanoporous membrane capable of concentrating THMs in a contaminated aqueous sample. The developed device has successfully lowered the portable single-step visible THM detection concentration by an order of magnitude (80ppm→80ppb). This sensor was also successfully applied for the determination of the total THM (t-THM) concentration in spiked and actual treated water samples, and these results correlated well with the GC/MS results of the corresponding sample, showing its real world applicability.

Detection of halogenated organics by their inhibitory action in a catalytic reaction between dimethyl acetylenedicarboxylate and 2-methyl-4-nitroaniline

The purpose of this paper is to report on the detection of toxic halogenated organic compounds in water using their inhibitory action on a pyridine-catalyzed reaction between dimethyl acetylenedicarboxylate (DMAD) and 2-methyl-4-nitroaniline (MNA). Previous work has shown that similar techniques can successfully lower the detection limit of sulfides and arsines in water samples, compared to their standard photometric detection methods. This paper highlights the optimization, selectivity, and sensitivity studies of the proposed sensing scheme. Optimization shows that the pyridine-catalyzed reaction is more favorable at 4 mM DMAD and 8 mM MNA. It was also determined that the inhibitory effect of halogenated organic compounds is more pronounced when carried out at 60°C. Using optimized reaction conditions, the limit of quantification for the four regulated trihalomethanes (THMs) was approximately 80 ppm. In addition, the sensing method is selective to THMs and a few other halogenated organics. These promising results demonstrate the further success of this technique for sensitive, selective detection, and future work will be carried out to incorporate the technique in sensing applications for THMs in drinking water.

Identifying bioaccumulative halogenated organic compounds using a nontargeted analytical approach: seabirds as sentinels.

Persistent organic pollutants (POPs) are typically monitored via targeted mass spectrometry, which potentially identifies only a fraction of the contaminants actually present in environmental samples. With new anthropogenic compounds continuously introduced to the environment, novel and proactive approaches that provide a comprehensive alternative to targeted methods are needed in order to more completely characterize the diversity of known and unknown compounds likely to cause adverse effects. Nontargeted mass spectrometry attempts to extensively screen for compounds, providing a feasible approach for identifying contaminants that warrant future monitoring. We employed a nontargeted analytical method using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) to characterize halogenated organic compounds (HOCs) in California Black skimmer (Rynchops niger) eggs. Our study identified 111 HOCs; 84 of these compounds were regularly detected via targeted approaches, while 27 were classified as typically unmonitored or unknown. Typically unmonitored compounds of note in bird eggs included tris(4-chlorophenyl)methane (TCPM), tris(4-chlorophenyl)methanol (TCPMOH), triclosan, permethrin, heptachloro-1'-methyl-1,2'-bipyrrole (MBP), as well as four halogenated unknown compounds that could not be identified through database searching or the literature. The presence of these compounds in Black skimmer eggs suggests they are persistent, bioaccumulative, potentially biomagnifying, and maternally transferring. Our results highlight the utility and importance of employing nontargeted analytical tools to assess true contaminant burdens in organisms, as well as to demonstrate the value in using environmental sentinels to proactively identify novel contaminants.

Nontargeted biomonitoring of halogenated organic compounds in two ecotypes of bottlenose dolphins (Tursiops truncatus) from the Southern California Bight.

Targeted environmental monitoring reveals contamination by known chemicals, but may exclude potentially pervasive but unknown compounds. Marine mammals are sentinels of persistent and bioaccumulative contaminants due to their longevity and high trophic position. Using nontargeted analysis, we constructed a mass spectral library of 327 persistent and bioaccumulative compounds identified in blubber from two ecotypes of common bottlenose dolphins (Tursiops truncatus) sampled in the Southern California Bight. This library of halogenated organic compounds (HOCs) consisted of 180 anthropogenic contaminants, 41 natural products, 4 with mixed sources, 8 with unknown sources, and 94 with partial structural characterization and unknown sources. The abundance of compounds whose structures could not be fully elucidated highlights the prevalence of undiscovered HOCs accumulating in marine food webs. Eighty-six percent of the identified compounds are not currently monitored, including 133 known anthropogenic chemicals. Compounds related to dichlorodiphenyltrichloroethane (DDT) were the most abundant. Natural products were, in some cases, detected at abundances similar to anthropogenic compounds. The profile of naturally occurring HOCs differed between ecotypes, suggesting more abundant offshore sources of these compounds. This nontargeted analytical framework provided a comprehensive list of HOCs that may be characteristic of the region, and its application within monitoring surveys may suggest new chemicals for evaluation.

Novel nano-catalysts for wastewater treatment

The present paper aims at a treatment technique designed for special industrial wastewaters contaminated with only traces of halogenated organic compounds (HOCs) – concentrations which are nevertheless large enough to make a discharge into municipal sewage works impossible. Our research follows the idea to detoxify the water by a selective destruction of the HOCs by hydrodehalogenation (HDH) reactions on palladium-containing nano-catalysts. Detoxification means that persistent HOCs are converted into organic compounds which can easily be removed by biodegradation in a wastewater treatment plant. A novel promising trend in environmental research is the application of nano-reagents (such as zero-valent iron) and nano-catalysts. As known from nano-sized metal particles, nanocatalysts have the advantage of very high reaction rates due to high specific surface areas and low mass-transfer restrictions. For special applications in wastewater treatment we were able to generate extremely active palladium catalysts on the basis of ferromagnetic carrier colloids. The magnetic nano-sized carriers (such as zero-valent iron or magnetite) were spiked with traces of Pd (0.1 wt.-%). These nano-catalysts have been successfully tested in different reactor systems at the laboratory scale. Using Pd on nano-scale supports leads to enormous activity of the catalyst which is several orders of magnitude higher than reached in conventional fixed-bed reactors. The ferromagnetism of the carriers enables a separation of the catalysts from the treated water by means of magneto-separation. This gives the chance to reuse the catalyst several times. The preferred reductant for the HDH reaction is molecular hydrogen. For highly contaminated waters, alternative hydrogen donors such as formic acid have been successfully tested.

Pt/Pd/Fe Trimetallic Nanoparticle Produced via Reverse Micelle Technique: Synthesis, Characterization, and Its Use as an Efficient Catalyst for Reductive Hydrodehalogenation of Aryl and Aliphatic Halides under Mild Conditions

The Pt/Pd/Fe trimetallic nanoparticle (Pt/Pd/Fe T-NP) was prepared using a water-in-oil microemulsion system of water/AOT/isooctane at room temperature. This nanoparticle (NP) was physically characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF) analyses. The said NP was used as catalyst for hydrodehalogenation (HDH) of halogenated organic compounds (HOCs), and its capability in hydrodechlorination (HDC) of chlorobenzene was compared with Pt/Pd, Pt/Fe, and Pd/Fe bimetallic nanoparticles (B-NPs) synthesized via the same method. The formation of mixed Pt/Pd/Fe ensembles results in an enhanced overall activity and reusability of HDC reaction, compared with Pd/Fe catalyst which acted as the best B-NP. Recycling experiments were examined for HDC of chlorobenzene. To get a maximum conversion of HDC, the reaction parameters like the effect of solvent, amounts of catalyst and ammonium formate were optimized. According to the results, HOCs, including electron-withdrawing and electron-donating substrates, were reduced smoothly. Finally, a mechanism for HDH reaction on the Pt/Pd/Fe catalyst surface was proposed.

Efficient Reductive Dechlorination of Monochloroacetic Acid by Sulfite/UV Process

Most halogenated organic compounds (HOCs) are toxic and persistent, and their efficient destruction is currently a challenge. Here, we proposed a sulfite/UV (253.7 nm) process to eliminate HOCs. Monochloroacetic acid (MCAA) was selected as the target compound and was degraded rapidly in the sulfite/UV process. The degradation kinetics were accelerated proportionally to the increased sulfite concentration, while the significant enhancement by increasing pH only occurred in a pH range of 6.0-8.7. The degradation proceeded via a reductive dechlorination mechanism induced by hydrated electron (e(aq)(-)), and complete dechlorination was readily achieved with almost all the chlorine atoms in MCAA released as chloride ions. Mass balance (C and Cl) studies showed that acetate, succinate, sulfoacetate, and chloride ions were the major products, and a degradation pathway was proposed. The dual roles of pH were not only to regulate the S(IV) species distribution but also to control the interconversion between e(aq)(-) and H(•). Effective quantum efficiency (Φ) for the formation of e(aq)(-) in the process was determined to be 0.116 ± 0.002 mol/einstein. The present study may provide a promising alternative for complete dehalogenation of most HOCs and reductive detoxification of numerous toxicants.

Lysosomal and lipid-associated parameters in the livers of three species of arctic seabird chicks: Species differences and relationships with contaminant levels

Lysosomal membrane stability, lipofuscin (LF), malondialdehyde (MDA), neutral lipid (NL) levels, as well as halogenated organic compounds (HOCs), Cr, Cd, Pb and Fe concentrations were analyzed in liver of black-legged kittiwake (BK), herring gull (HG), and northern fulmar (NF) chicks. There were significant species differences in the levels of NL, LF and lysosomal membrane stability. These parameters were not associated with the respective HOC concentrations. LF accumulation was associated with increasing Cr, Cd and Pb concentrations. HG presented the lowest lysosomal membrane stability and the highest.LF and NL levels, which indicated impaired lysosomes in HG compared to NF and BK. Lipid peroxidation was associated with HOC and Fe2+ levels. Specific HOCs showed positive and significant correlations with MDA levels in HG. The study indicates that contaminant exposure can affect lysosomal and lipid associated parameters in seabird chicks even at low exposure levels. These parameters may be suitable markers of contaminant induced stress in arctic seabirds.

Formation of Trihalomethanes during Seawater Chlorination

The use of seawater for industrial cooling is a vital technology that poses some of the most profound environmental impact on the water quality in the Arabian Gulf. Biocide (chlorine) is added to the seawater to control biofouling of the cooling system. This added chlorine reacts with bromide and other chemicals naturally exist in the water to form a wide range of oxidants. Regrettably, reactions between the residual oxidants and natural organic matter in the water lead to formation of toxic halogenated organic compounds that have detrimental effects on the environment when they are discharged into the Gulf. This paper describes the formation of trihalomethanes (THMs) in seawater cooling systems. Results of kinetic experiments have shown that concentrations of THMs increased rapidly with time during the first half hour. Chlorination of seawater has shown significant increase in total THMs (TTHMs) and in bromoform concentrations. Rapid decrease of UV absorbance at 254 nm was also observed during seawater chlorination which is indicative of natural organic matter degradation into small organic molecules including THMs and other by-products. The increase in chlorine dose was accompanied with an increase in TTHMs and bromoform concentrations. Linear relationships between total chlorine concentration and both final TTHMs and bromoform concentrations were established. First order exponential decay and exponential associate functions were developed to correlate chlorine dose with formed THMs.

Dispersive liquid–liquid microextraction method based on solidification of floating organic drop combined with gas chromatography with electron-capture or mass spectrometry detection

A simple dispersive liquid–liquid microextraction (DLLME) method based on solidification of a floating organic drop (DLLME-SFO) technique combined with gas chromatography/electron-capture detection (GC/ECD) or gas chromatography/mass spectrometry (GC/MS) has been developed. The proposed method is simple, low in cost, and of high precision. It overcomes the most important problem in DLLME, the high-toxic solvent used. Halogenated organic compounds (HOCs) in water samples were determined as the model compounds. The parameters optimized for the DLLME-SFO technique were as follows: A mixture of 0.5 mL acetone, containing 10 μL 2-dodecanol (2-DD-OH), was rapidly injected by syringe into the 5 mL water sample. After centrifugation, the fine 2-DD-OH droplets (8 ± 0.5 μL) were floated at the top of the screwcap test tube. The test tube was then cooled in an ice bath. After 5 min the 2-DD-OH solvent had solidified and was then transferred into a conical vial; it melted quickly at room temperature and 3 μL (for GC/ECD) or 2 μL (for GC/MS) of it was injected into a gas chromatograph for analysis. The limit of detection (LOD) for this technique was 0.005–0.05 μg L −1 for GC/ECD and was 0.005–0.047 μg L −1 for GC/MS, respectively. The linear range of the calibration curve of DLLME-SFO was from 0.01 to 500 μg L −1 with a coefficient of estimation ( r 2) > 0.996 for GC/ECD and was from 0.02 to 500 μg L −1 with a coefficient of estimation ( r 2) > 0.996 for GC/MS.

Completely Automated System for Determining Halogenated Organic Compounds by Multisyringe Flow Injection Analysis

A new, multisyringe flow injection setup was designed to develop the first completely automated flow methodology for the expeditious, accurate in-line determination of halogenated organic compounds (HOCs) in water. The target compounds are preconcentrated and isolated by solid-phase extraction. Following elution, previously organically bound halogens are released as free hydrogen halides by the combined action of UV light and a chemical oxidant for their subsequent spectrophotometric determination by reaction with Hg(SCN) 2 and Fe(3+). Optimizing the major hydrodynamic and chemical variables resulted in improved performance. Recovery of various HOCs was assessed, and potential interferents were examined. Under the selected operating conditions, the proposed method exhibits variable analytical performance depending on the particular sample volume used (e.g., a sample volume of 5 mL provides a linear working range of 140-2000 microg L(-1), a LOD of 100 microg L(-1), and a throughput of 9 samples h(-1)). The method was successfully used to determine total adsorbable organic halogens (AOX) in well water and leachates, and the results validated against an AOX reference method. The role of the proposed system in the environmental analytical field is critically discussed.

The use of carbon sorbents and sorption technologies for cleaning water systems of petroleum products

Sorbtional properties of carbonic sorbents on the base of pine sawdust in the processes of purification of water mediums and complicated technological solution from petroleum products and phosphorus compounds are investigated. The possibility of carbonic sorbents modification by halogen organic compounds to increase the degree of purification of water ecosystems is analyzed.

Efficient fully controlled up-to-date equipment for catalytic treatment of waste gases

This paper describes research and development of a new unit for catalytic destruction of waste gases polluted mainly by volatile organic compounds (VOC), halogenated organic compounds (HOC) or carbon monoxide. Novel equipment has considerable advantages compared with commonly used arrangement (combustion chamber (catalytic reactor)–pipeline–heat exchanger). It is very compact and light and has the combustion chamber, catalytic reactor and heat exchanger integrated into one unit. Maximum utilizing heat losses in the combustion chamber and catalytic reactor is achieved. During the development of this unit experience from tests of previously developed equipment used for thermal treatment of waste gases was used, as well as from experimental studies of catalytic disposal of various VOC carried out in the newly built experimental unit. During the development calculation methods were created allowing design modifications of this unit for real industrial applications. The newly developed unit can be used in various branches of industry such as paint shops, refining plants, sewage treatment plants, food processing industry, pharmaceutical industry, but also in companies processing and transporting crude-oil or natural gas, etc.

Use of hepatocytes from Hoplias malabaricus to characterize the toxicity of a complex mixture of lipophilic halogenated compounds

Organisms are continuously exposed to a plethora of anthropogenic toxicants daily released to the environment. In the present study, the effects of a mixture of halogenated organic compounds (HOCs) extracted from hepatic lipids were evaluated on the primary hepatocyte culture from fish Hoplias malabaricus. Cells were isolated through non-enzymatic perfusion protocol and cultured during 3 days to allow attachment. Two concentrations of the mixture of HOCs (10 ng ml −1 [Mix10] and 50 ng ml −1 [Mix50]) were tested in cells for 2 days by medium replacement. The control groups, with and without solvent (DMSO) were run in the same conditions. Both tested concentrations of HOCs increased the catalase and GST activities, but only the Mix50 increase the DNA damage and decreased the GSH concentration and cell viability. Lipid peroxidation increased in the Mix10 group, but it seems to be more a consequence of DMSO presence than the HOCs themselves. The DMSO at 0.1% increased the lipid peroxidation, GSH concentration, apoptosis and DNA damage. The present data suggest that DMSO interferes with the hepatocytes of H. malabaricus in culture and that the mixture of HOCs tested alters the redox state of the hepatocytes.