Determination of semi-volatile priority pollutants in landfill leachates and sediments using microwave-assisted headspace solid-phase microextraction

Unveiling the occurrence, distribution, removal, and environmental impacts of 65 emerging contaminants in neglected fresh leachate from municipal solid waste incineration plants

Emerging contaminants (ECs) are commonly found in environmental media. Yet leachate from municipal solid waste incineration plants (MSWIPs), which can serve as a reservoir for various contaminants, including ECs, has received little investigation. To address this gap, 65 ECs were analyzed in the fresh leachate and biological effluent from three major MSWIPs in Shanghai. Results indicated that over half (56%) of the 65 ECs were detected in fresh leachate. Different ECs would be removed to varying degrees after biological treatment, including polycyclic aromatic hydrocarbons (PAHs) (65%), polybrominated diphenyl ethers (PBDEs) (51%), phthalate esters (PAEs) (36%), and organophosphorus pesticides (OPPs) (34%). Notably, for tetrabromobisphenol A (TBBPA), a PBDE substitute, only 2% was removed after biological treatment, while polychlorinated biphenyls (PCBs) were effectively removed at 83%. Water solubility and the octanol-water partition coefficient are key factors influencing the distribution and removal of ECs in leachate. the effluent will still contain refractory ECs even after the biological treatment. These residual ECs discharged to sewers can impact wastewater treatment plants or contaminate surface water and groundwater. These findings provide insights into the leachate contamination by ECs, their environmental fate, factors affecting their behavior, and potential environmental impacts.

Biomonitoring of polycyclic aromatic hydrocarbons (PAHs) by Murraya paniculata (L.) Jack in South Kolkata, West Bengal, India: spatial and temporal variations

Attempts have been made in the present study for ascertaining the concentrations of atmospheric polycyclic aromatic hydrocarbons (PAHs) using passive biosamplers in preference to conventional air sampling methods. Mechanical stirring, sonication, Soxhlet technique and microwave-assisted Soxhlet extraction (MASE) were employed to extract PAHs from an evergreen plant (Murraya paniculata) leaves (having long life-span) sampled from polluted places of South Kolkata, India, with dense population and heavy traffic. Effects of extraction methods and operational parameters (solvent and time) on the recovery levels of PAHs were also investigated. Purified extracts, acquired through adsorption chromatography, were subjected to GC-MS and HPLC-UV analyses for qualitative and quantitative assessment of PAHs. Spatio-temporal distribution of accumulated PAHs across the sampling sites was monitored over premonsoon, postmonsoon and winter supported by pollutant source characterization. The results displayed that the extraction yields of Soxhlet (272.07 ± 26.15 μg g-1) and MASE (280.17 ± 15.46 μg g-1) were the highest among the four techniques. Conditions of extraction with toluene for 6 h were found to be most favorable for PAHs. In spatio-temporal analysis, total concentrations of PAHs in the foliar samples varied from 200.98 ± 2.72 to 550.79 ± 10.11 μg g-1 dry weight, and the highest values being recorded in the samples of Exide More because of daylong inexorable traffic flow/crowding increasing the burden of ambient PAHs. Widespread changes in meteorology exerted influence on seasonal concentrations of PAHs in plant leaves, and extent of leaf contamination by PAHs was observed extreme in winter followed by postmonsoon and then, premonsoon. Foliar accretion of PAHs differed in the study sites with diverse sources of emission from motor vehicles, fossil fuel and biomass burning along with other human interferences.

55 xenobiotic organic compounds in Tripoli landfill-Lebanon leachate and their fluxes to the Abou Ali River and Mediterranean Sea

Pollution generated from landfill solid wastes constitute one of the major threat to the environment. The landfill leachate contains various toxic pollutants, making it the most dangerous issue of the landfills. Monitoring the xenobiotic organic concentrations in landfill leachate is an important step to evaluate the environmental impacts. This work aims to characterize the seasonal variation of 55 xenobiotic organic compounds including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalic acid esters (PAEs) and bisphenols (BPs) in the leachate from municipal solid waste landfill of Tripoli, Lebanon. And also, the quantity of the pollutant's flux to the Abou Ali River and the Mediterranean Sea nearby has been estimated. The organic pollutants were extracted by using the solid-phase extraction and quantified by using GC-MS/MS. The results showed high level of PAEs, BPs, PCBs, and PAHs in the leachate samples. The fluxes of pollutants to the Abou Ali River and Mediterranean Sea have been detected at 0.23 kg, 0.01 kg, 116.85 kg, 15.93 kg, and 7.58 kg for Σ₁₆PAHs, Σ₂₈PCBs, Σ₆PAEs, Σ₄BPs, and 4-NP respectively.

The presence, emission and partitioning behavior of polychlorinated biphenyls in waste, leachate and aerosols from Norwegian waste-handling facilities

Even though production and open use of polychlorinated biphenyls (PCBs) have been phased out in Western industrialised countries since the 1980s, PCBs were still present in waste collected from different waste handling facilities in Norway in 2013. Sums of seven indicator-PCBs (I-PCB₇: PCB-28, -52, -101, -118, -138, -153 and -180) were highest in plastic waste (3700 ±1800 μg/kg, n=15), waste electrical and electronic equipment (WEEE) (1300 ± 400 μg/kg, n=12) and fine vehicle fluff (1800 ± 1400 μg/kg, n=4) and lowest in glass waste, combustibles, bottom ash and fly ash (0.3 to 65 μg/kg). Concentrations in leachate water varied from 1.7 to 2900 ng/L, with higher concentrations found at vehicle and WEEE handling facilities. Particles in leachate water exhibited similar PCB sorption properties as solid waste collected on site, with waste-water partitioning coefficients ranging from 10⁵ to 10⁷. I-PCB₇ in air samples collected at the sites were mostly in the gas phase (100-24000 pg/m³), compared to those associated with particles (9-1900 pg/m³). In contrast, brominated flame retardants (BFRs) in the same samples were predominantly found associated with particles (e.g. sum of 10 brominated diethyl ethers, ΣBDE₁₀, associated with particles 77-194,000 pg/m³) compared to the gas phase (ΣBDE₁₀ 6-473 pg/m³). Measured gas-phase I-PCB₇ concentrations are less than predicted, assuming waste-air partitioning in equilibrium with predominant waste on site. However, the gas-particle partitioning behavior of PCBs and BFRs could be predicted using an established partitioning model for ambient aerosols. PCB emissions from Norwegian waste handling facilities occurred primarily in the form of atmospheric vapor or leachate particles.

Field Analysis of Polychlorinated Biphenyls (PCBs) in Soil Using Solid-Phase Microextraction (SPME) and a Portable Gas Chromatography-Mass Spectrometry System

An expedited field analysis method was developed for the determination of polychlorinated biphenyls (PCBs) in soil matrices using a portable gas chromatography-mass spectrometry (GC-MS) instrument. Soil samples of approximately 0.5 g were measured with a portable scale and PCBs were extracted by headspace solid-phase microextraction (SPME) with a 100 µm polydimethylsiloxane (PDMS) fiber. Two milliliters of 0.2 M potassium permanganate and 0.5 mL of 6 M sulfuric acid solution were added to the soil matrices to facilitate the extraction of PCBs. The extraction was performed for 30 min at 100 ℃ in a portable heating block that was powered by a portable generator. The portable GC-MS instrument took less than 6 min per analysis and ran off an internal battery and helium cylinder. Six commercial PCB mixtures, Aroclor 1016, 1221, 1232, 1242, 1248, 1254, and 1260, could be classified based on the GC chromatograms and mass spectra. The detection limit of this method for Aroclor 1260 in soil matrices is approximately 10 ppm, which is sufficient for guiding remediation efforts in contaminated sites. This method was applicable to the on-site analysis of PCBs with a total analysis time of 37 min per sample. However, the total analysis time could be improved to less than 7 min per sample by conducting the rate-limiting extraction step for different samples in parallel.

Hasse diagram as a green analytical metrics tool: ranking of methods for benzo[a]pyrene determination in sediments

This study presents an application of the Hasse diagram technique (HDT) as the assessment tool to select the most appropriate analytical procedures according to their greenness or the best analytical performance. The dataset consists of analytical procedures for benzo[a]pyrene determination in sediment samples, which were described by 11 variables concerning their greenness and analytical performance. Two analyses with the HDT were performed—the first one with metrological variables and the second one with “green” variables as input data. Both HDT analyses ranked different analytical procedures as the most valuable, suggesting that green analytical chemistry is not in accordance with metrology when benzo[a]pyrene in sediment samples is determined. The HDT can be used as a good decision support tool to choose the proper analytical procedure concerning green analytical chemistry principles and analytical performance merits.

Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes

In recent years, electrochemical advanced oxidation processes have been shown to be an effective alternative for the removal of refractory organic compounds from water. This study is focused on the effective removal of recalcitrant organic matter (micropollutants, humic substances, etc.) present in municipal solid waste landfill leachates. A mixture of eight landfill leachates has been studied by the electro-Fenton process using a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode or by the anodic oxidation process with a BDD anode. These processes exhibit great oxidation ability due to the in situ production of hydroxyl radicals ((•)OH), a highly powerful oxidizing species. Both electrochemical processes were shown to be efficient in the removal of dissolved total organic carbon (TOC) from landfill leachates. Regarding the electro-Fenton process, the replacement of the classical anode Pt by the anode BDD allows better performance in terms of dissolved TOC removal. The occurrence and removal yield of 19 polycyclic aromatic hydrocarbons, 15 volatile organic compounds, 7 alkylphenols, 7 polychlorobiphenyls, 5 organochlorine pesticides, and 2 polybrominated diphenyl ethers in landfill leachate were also investigated. Both electrochemical processes allow one to reach a quasicomplete removal (about 98%) of these organic micropollutants.

Sorption and degradation of petroleum hydrocarbons, polycyclic aromatic hydrocarbons, alkylphenols, bisphenol A and phthalates in landfill leachate using sand, activated carbon and peat filters

Landfill leachates are repeatedly found contaminated with organic pollutants, such as alkylphenols (APs), phthalates and polycyclic aromatic hydrocarbons (PAHs) at levels exceeding water quality standards. It has been shown that these pollutants may be present in the colloidal and truly dissolved phase in contaminated water, making particle separation an inefficient removal method. The aim of this study was to investigate sorption and degradation of petroleum hydrocarbons (PHCs), selected APs, bisphenol A (BPA), phthalates and PAHs from landfill leachate using sand, granulated activated carbon (GAC) and peat moss filters. A pilot plant was installed at an inactive landfill with mixed industrial and household waste and samples were collected before and after each filter during two years. Leachate pre-treated in oil separator and sedimentation pond failed to meet water quality standards in most samples and little improvement was seen after the sand filter. These techniques are based on particle removal, whereas the analysed pollutants are found, to varying degrees, bound to colloids or dissolved. However, even highly hydrophobic compounds expected to be particle-bound, such as the PHCs and high-molecular weight PAHs, were poorly removed in the sand filter. The APs and BPA were completely removed by the GAC filter, while mass balance calculations indicate that 50-80% of the investigated phenols were removed in the peat filter. Results suggest possible AP degradation in peat filters. No evidence of phthalate degradation in the landfill, pond or the filters was found. The PHCs were completely removed in 50% and 35% of the measured occasions in the GAC and peat filters, respectively. The opposite trend was seen for removal of PAHs in GAC (50%) and peat (63%). Oxygenated PAHs with high toxicity were found in the leachates but not in the pond sediment. These compounds are likely formed in the pond water, which is alarming because sedimentation ponds are commonly used treatment techniques. The oxy-PAHs were effectively removed in the GAC, and especially the peat filter. It was hypothesized that dissolved compounds would adsorb equally well to the peat and GAC filters. This was not completely supported as the GAC filter was in general more efficient than peat.

Partitioning of polycyclic aromatic hydrocarbons, alkylphenols, bisphenol A and phthalates in landfill leachates and stormwater

Partitioning of organic pollutants is essential to their fate, mobility and removal from water and soil. To study the partitioning behavior of selected alkylphenols, bisphenol A, phthalates and polycyclic aromatic hydrocarbons (PAHs), a method for separating the truly dissolved and colloidal phase of organic pollutants was developed, verified and applied to samples of landfill leachate and stormwater from urban areas and waste-sorting sites. Alkylphenols, bisphenol A, phthalates and PAHs were detected in all the untreated samples (total concentrations), most of the filtered samples and frequently in the colloid-bound phase. Concentrations of alkylphenols and PAHs in urban stormwater were one order of magnitude lower than in the landfill leachates and stormwater from waste-sorting sites. The difference between total, dissolved and colloid-bound concentrations in the water samples was not statistically significant for any phenols or phthalates, but for three of the PAHs; naphthalene (mostly dissolved), phenanthrene and fluoranthene (mostly particulate). These results indicate that in landfill leachates and stormwaters, organic pollutants are predominantly attached to colloids and/or truly dissolved in contrast to their expected strong sorption to particulate matter. Occurrence and concentrations of pollutants in dissolved and colloid-bound phases correlated negatively with the K(OW). However, even highly hydrophobic compounds were frequently detected in filtered samples, i.e. the dissolved phases, and it is suggested that the organic content in the colloids decreases the compounds' partition to particles. The results confirm that the K(OW) values of specific organic pollutants well describe the compounds partition-binding process to dissolved organic carbon (DOC) colloids. Our findings call for a re-assessment of the organic pollutants' mobility and associated risks. This knowledge can also serve as a base for selecting efficient treatment methods for stormwater and landfill leachates.

Microwave-assisted headspace solid-phase microextraction to quantify polycyclic aromatic hydrocarbons in pine trees

A methodology for the extraction and quantification of 16 polycyclic aromatic hydrocarbons (PAHs) based on microwave-assisted extraction coupled with headspace solid-phase microextraction followed by gas chromatography/mass spectroscopy was validated for needles and bark of two pine species (Pinus pinaster Ait. and Pinus pinea L.). The limits of detection were below 0.92 ng g(-1) (dry weight) for needles and below 0.43 ng g(-1) (dw) for bark. Recovery assays were performed with two sample masses spiked at three levels and the overall mean values were between 70 and 110 % for P. pinaster and 75 and 129 % for P. pinea. In the first species, the increase in sample mass lowered the recoveries slightly for most PAHs, whereas for the second, the recoveries were higher for the needles. Naturally contaminated samples from 4 sites were analysed, with higher levels for urban sites (1,320 and 942 ng g(-1) (dw) vs. 272 and 111 ng g(-1) (dw) for needles and 696 and 488 ng g(-1) (dw) vs. 270 and 103 ng g(-1) (dw) for bark) than for rural ones and also for P. pinaster samples over P. pinea. It is also shown that gas-phase PAHs are predominant in the needles (over 65 % of the total PAHs) and that the incidence for particulate material in bark, reaching 40 % as opposed to a maximum below 20 % for the needles. The method has proved to be fit and improved some of the existing approaches, on the assessment of particulate PAHs and bark levels.

Development of microwave-assisted extraction procedure for organic impurity profiling of seized 3,4-methylenedioxymethamphetamine (MDMA)

Organic impurity profiling of seized 3,4-methylenedioxymethamphetamine (MDMA) tablets aims to link tablets to common production sources. Conventionally, organic impurities are extracted from tablets using a liquid-liquid extraction (LLE) procedure prior to analysis by gas chromatography-mass spectrometry (GC-MS). In this research, the development of an alternative microwave-assisted extraction/headspace solid-phase microextraction (MAE/HS-SPME) procedure is described. The optimal procedure used phosphate buffer (1 M, pH 8), with an HS-SPME extraction temperature of 70 °C for 40 min, using a divinylbenzene/Carboxen™/polydimethylsiloxane (DVB/CAR/PDMS) fiber. Impurities were extracted from seized MDMA exhibits using the MAE/HS-SPME procedure, as well as HS-SPME alone, and a conventional LLE procedure. The HS-SPME procedure was deemed to be the most practical because of the affordability and need for less analyst involvement. Although the LLE was limited in the number of impurities extracted, the procedure is still useful for the extraction of less volatile impurities that are not extracted by HS-SPME.

Microwave-assisted headspace solid-phase microextraction for the rapid determination of organophosphate esters in aqueous samples by gas chromatography-mass spectrometry

The rapid and solvent-free determination of organophosphate esters (OPEs) in aqueous samples via one-step microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis is described. Tri-n-butyl phosphate (TnBP) and tris-(2-ethylhexyl) phosphate (TEHP) were selected as model compounds for the method of development and validation. The effects of various extraction parameters for the quantitative extraction of these analytes by MA-HS-SPME were systematically investigated and optimized. The analytes, in a 20 mL water sample (in a 40 mL sample bottle containing 2g of NaCl, pH 3.0), were efficiently extracted by a polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber placed in the headspace when the system was microwave irradiated at 140 W for 5 min. The limits of quantification (LOQs) for TnBP and TEHP were 0.5 and 4 ng/L, respectively. Using the standard addition method, MA-HS-SPME coupled with GC-MS was utilized to determine selected OPEs in surface water and wastewater treatment plants (WWTP) influent/effluent samples. Preliminary results show that TnBP was commonly detected OPEs in these aqueous samples, the correlation coefficients (r(2)) of the standard addition curves were greater than 0.9822, indicating that the developed method appears to be a good alternative technique for analyzing OPEs in aqueous samples.

Levels and sources of PAHs in selected sites from Portugal: biomonitoring with Pinus pinea and Pinus pinaster needles

Pine needle samples from two pine species (Pinus pinaster Ait. and Pinus pinea L.) were collected at 29 sites scattered throughout Portugal, in order to biomonitor the levels and trends of 16 polycyclic aromatic hydrocarbons (PAHs). The values obtained for the sum of all PAHs ranged from 76 to 1944 ng/g [dry weight (dw)]. Despite the apparent matrix similarities between both pine species, P. pinaster needles revealed higher mean entrapment levels than P. pinea (748 and 399 ng/g (dw) per site, respectively). The urban and industrial sites have the highest average of PAH incidence [for P. pinea, 465 and 433 ng/g (dw) per site, respectively, and for P. pinaster, 1147 and 915 ng/g (dw)], followed by the rural sites [233 ng/g and 711 ng/g (dw) per site, for P. pinea and P. pinaster, respectively]. The remote sites, both from P. pinaster needles, show the least contamination, with 77 ng/g (dw) per site. A predominance of 3-ring and 4-ring PAHs was observed in most samples, with phenanthrene having 30.1% of the total. Naphthalene prevailed in remote sites. Rainfall had no influence on the PAHs levels, but there was a relationship between higher wind speeds and lower concentrations. PAH molecular ratios revealed the influence of both petrogenic and pyrogenic sources.

Novel approach to microwave-assisted extraction and micro-solid-phase extraction from soil using graphite fibers as sorbent

A single-step extraction-cleanup procedure involving microwave-assisted extraction (MAE) and micro-solid-phase extraction (micro-SPE) has been developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) from soil samples. Micro-SPE is a relatively new extraction procedure that makes use of a sorbent enclosed within a sealed polypropylene membrane envelope. In the present work, for the first time, graphite fiber was used as a sorbent material for extraction. MAE-micro-SPE was used to cleanup sediment samples and to extract and preconcentrate five PAHs in sediment samples prepared as slurries with addition of water. The best extraction conditions comprised of microwave heating at 50 degrees C for a duration of 20 min, and an elution (desorption) time of 5 min using acetonitrile with sonication. Using gas chromatography (GC)-flame ionization detection (FID), the limits of detection (LODs) of the PAHs ranged between 2.2 and 3.6 ng/g. With GC-mass spectrometry (MS), LODs were between 0.0017 and 0.0057 ng/g. The linear ranges were between 0.1 and 50 or 100 microg/g for GC-FID analysis, and 1 and 500 or 1000 ng/g for GC-MS analysis. Granular activated carbon was also used for the micro-SPE device but was found to be not as efficient in the PAH extraction. The MAE-micro-SPE method was successfully used for the extraction of PAHs in river and marine sediments, demonstrating its applicability to real environmental solid matrixes.

Evaluation of solid-phase microextraction conditions for the determination of polycyclic aromatic hydrocarbons in aquatic species using gas chromatography

This paper describes a headspace solid-phase microextraction (HS-SPME) procedure coupled to gas chromatography with mass spectrometric detection (GC-MS) for the determination of eight PAHs in aquatic species. The influence of various parameters on the PAH extraction efficiency was carefully examined. At 75 degrees C and for an extraction time of 60 min, a polydimethylsiloxane-divinylbenzene (PDMS/DVB) fiber coating was found to be most suitable. Under the optimized conditions, detection limits ranged from 8 to 450 pg g(-1), depending on the compound and the sample matrix. The repeatability varied between 7 and 15% (RSD). Accuracy was tested using the NIST SRM 1974b reference material. The method was successfully applied to different samples, and the studied PAHs were detected in several of the samples.

Occurrence and removal of organic micropollutants in the treatment of landfill leachate by combined anaerobic-membrane bioreactor technology

Organic micropollutants, with high toxicity and environmental concern, are present in the landfill leachate at much lower levels than total organic constituents (chemical oxygen demand (COD), biochemical oxygen demand (BOD), or total organic carbon (TOC)), and few has been known for their behaviors in different treatment processes. In this study, occurrence and removal of 17 organochlorine pesticides (OCPs), 16 polycyclic aromatic hydrocarbons (PAHs), and technical 4-nonylphenol (4-NP) in landfill leachate in a combined anaerobic-membrane bioreactor (MBR) were investigated. Chemical analyses were performed in leachates sampled from different treatment processes, using solid-phase extraction and gas chromatography with electron capture detector and mass spectrometry. Concentrations of OCPs, PAHs, and 4-NP in the raw leachate were detected within the range from ND (not detected) to 595.2 ng/L, which were as low as only 10(-7)-10(-5) percentage of TOC (at the concentration of 2,962 mg/L). The removal of 4-NP was mainly established in the MBR process, in agreement with removals of COD, BOD, and TOC. However, the removals of OCPs and PAHs were different, mainly achieved in the anaerobic process. High removal efficiencies of both total organic constituents and organic micropollutants could be achieved by the combined anaerobic-MBR technology. The removal efficiencies of total organic constituents were in the order of BOD (99%) > COD (89%) > TOC (87%), whereas the removal efficiencies of investigated organic micropollutants were as follows: OCPs (94%) > 4-NP (77%) > PAHs (59%).

MALDI MS analysis of oligonucleotides: desalting by functional magnetite beads using microwave-assisted extraction

The presence of alkali cation adductions of oligonucleotides commonly deteriorates matrix-assisted laser desorption/ionization (MALDI) mass spectra. Thus, desalting is required for oligonucleotide samples prior to MALDI MS analysis in order to prevent the mass spectra from developing poor quality. In this paper, we demonstrate a new approach to extract traces of oligonucleotides from aqueous solutions containing high concentrations of salts using microwave-assisted extraction. The C18-presenting magnetite beads, capable of absorbing microwave irradiation, are used as affinity probes for oligonucleotides with the addition of triethylammonium acetate as the counterions. This new microwave-assisted extraction approach using magnetite beads as the trapping agents and as microwave-absorbers has been demonstrated to be very effective in the selective binding of oligonucleotides from aqueous solutions. The extraction of oligonucleotides from solutions onto the C18-presenting magnetite beads takes only 30 s to enrich oligonucleotides in sufficient quantities for MALDI MS analysis. After using this desalting approach, alkali cation adductions of oligonucleotides are dramatically reduced in the MALDI mass spectra. The presence of saturated NaCl (approximately 6 M) in the oligonucleotide sample is tolerated without degrading the mass spectra. The detection limit for d(A)6 is approximately 2.8 fmol.