Extraction of polycyclic aromatic hydrocarbons and organochlorine pesticides from soils: A comparison between Soxhlet extraction, microwave-assisted extraction and accelerated solvent extraction techniques

Biochemical Response of the Endogeic Earthworm (Balanteodrilus extremus) Exposed to Tropical Soils

This work evaluated the biochemical responses of the endogeic earthworm Balanteodrilus extremus exposed for 14 and 48 days (d) to soils collected from two tropical agricultural systems: maize-sorghum (MS) and soybean-sorghum (SS). A soil without agricultural management (WAM) and the use of pesticides was selected as a reference. The presence of organochlorine (OC) and organophosphate (OP) pesticide residues was quantified in MS and SS soils. Biomarkers of detoxification [glutathione S transferase (GST)], neurotoxicity [acetylcholinesterase (AChE)] and oxidative stress [superoxide dismutase (SOD), catalase (CAT) and lipoperoxidation (LPO)] were evaluated in B. extremus. The concentration of OP pesticide residues was higher in SS than in MS. Activity of AChE in B. extremus exposed to SS soil for 14 d was significantly more inhibited (78%) than in MS soil (68%). B. extremus has been shown to be a good bioindicator of contaminated soils in tropical regions.

A Review: Subcritical Water Extraction of Organic Pollutants from Environmental Matrices

Most organic pollutants are serious environmental concerns globally due to their resistance to biological, chemical, and photolytic degradation. The vast array of uses of organic compounds in daily life causes a massive annual release of these substances into the air, water, and soil. Typical examples of these substances include pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). Since they are persistent and hazardous in the environment, as well as bio-accumulative, sensitive and efficient extraction and detection techniques are required to estimate the level of pollution and assess the ecological consequences. A wide variety of extraction methods, including pressurized liquid extraction, microwave-assisted extraction, supercritical fluid extraction, and subcritical water extraction, have been recently used for the extraction of organic pollutants from the environment. However, subcritical water has proven to be the most effective approach for the extraction of a wide range of organic pollutants from the environment. In this review article, we provide a brief overview of the subcritical water extraction technique and its application to the extraction of PAHs, PCBs, pesticides, pharmaceuticals, and others form environmental matrices. Furthermore, we briefly discuss the influence of key extraction parameters, such as extraction time, pressure, and temperature, on extraction efficiency and recovery.

Simultaneous detection of pesticides and pharmaceuticals in three types of bio-based fertilizers by an improved QuEChERS method coupled with UHPLC-q-ToF-MS/MS

Bio-based fertilizers (BBFs) have the potential to contain both pesticides and pharmaceutical residues, which may pose a threat to soils, crops, and human health. However, no analytical screening method is available currently to simultaneously analyze a wide range of contaminants in the complex origin-dependent matrices of BBFs. To fill this gap, our study tested and improved an original QuEChERS method (OQM) for simultaneously analyzing 78 pesticides and 18 pharmaceuticals in BBFs of animal, plant, and ashed sewage sludge origin. In spiked recovery experiments, 34-58 pharmaceuticals and pesticides were well recovered (recovery of 70-120%) via OQM at spiking concentrations levels of 10 ng/g and 50 ng/g in these three different types of BBFs. To improve the extraction efficiency further, ultrasonication and end-over-end rotation were added based on OQM, resulting in the improved QuEChERS method (IQM) that could recover 57-79 pesticides and pharmaceuticals, in the range of 70-120%. The detection limits of this method were of 0.16-4.32/0.48-12.97 ng/g, 0.03-11.02/0.10-33.06 ng/g, and 0.06-5.18/0.18-15.54 ng/g for animal, plant, and ash-based BBF, respectively. Finally, the IQM was employed to screen 15 BBF samples of various origins. 15 BBFs contained at least one pesticide or pharmaceutical with ibuprofen being frequently detected in at concentration levels of 4.1-181 ng/g. No compounds were detected in ash-based BBFs.

Preparation of Novel Solid Phase Extraction Sorbents for Polycyclic Aromatic Hydrocarbons (PAHs) in Aqueous Media

In this study, functionalized mesoporous silica was prepared and characterized as a stationary phase using various analytical and solid-state techniques, including a Fourier-transform infrared (FTIR) spectrometer, thermogravimetric analysis, and nitrogen sorption. The results confirmed the successful synthesis of the hybrid stationary phase. The potential of the prepared hybrid mesoporous silica as a solid-phase extraction (SPE) stationary phase for separating and enriching polycyclic aromatic hydrocarbons (PAHs) in both spiked water samples and real water samples was evaluated. The analysis involved extracting the PAHs from the water samples using solid-phase extraction and analyzing the extracts using a two-dimensional gas chromatograph coupled to a time-of-flight mass spectrometer (GC × GC-TOFMS). The synthesized sorbent exhibited outstanding performance in extracting PAHs from both spiked water samples and real water samples. In the spiked water samples, the recoveries of the PAHs ranged from 79.87% to 95.67%, with relative standard deviations (RSDs) ranging from 1.85% to 8.83%. The limits of detection (LOD) for the PAHs were in the range of 0.03 µg/L to 0.04 µg/L, while the limits of quantification (LOQ) ranged from 0.05 µg/L to 3.14 µg/L. Furthermore, all the calibration curves showed linearity, with correlation coefficients (r) above 0.98. Additionally, the results from real water samples indicated that the levels of individual PAH detected ranged from 0.57 to 12.31 µg/L with a total of 44.67 µg/L. These findings demonstrate the effectiveness of the hybrid mesoporous silica as a promising stationary phase for solid-phase extraction and sensitive detection of PAHs in water samples.

Clinical potential and mechanistic insights of mulberry (Morus alba L.) leaves in managing type 2 diabetes mellitus: Focusing on gut microbiota, inflammation, and metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Natural herbs are gradually gaining recognition for their efficacy and safety in preventing diabetes and improving quality of life. Morus alba L. is a plant widely grown in Asia and is a traditional Chinese herb with a long history of use. Furthermore, several parts of Morus alba L. have been found to have significant health benefits. In particular, mulberry (Morus alba L.) leaves (ML) have been shown in human and animal studies to be promising hypoglycemic agents that can reduce or prevent glucolipid metabolism disorders caused by imbalances in the gut microbiota, inflammation, and oxidative stress and have demonstrated significant improvements in glucose metabolism-related markers, effectively lowering blood glucose, and reducing hyperglycemia-induced target organ damage.

AIM OF THE STUDY

This review briefly summarizes the methods for obtaining ML's bioactive components, elaborates on the clinical potential of the relevant components in managing type 2 diabetes mellitus (T2DM), and focuses on the therapeutic mechanisms of gut microbiota, inflammation, oxidative stress, and metabolism, to provide more inspiration and directions for future research in the field of traditional natural plants for the management of T2DM and its complications.

MATERIALS AND METHODS

Research on ML and its bioactive components was mainly performed using electronic databases, including PubMed, Google Scholar, and ScienceNet, to ensure the review's quality. In addition, master's and doctoral theses and ancient documents were consulted.

RESULTS

In clinical studies, we found that ML could effectively reduce blood glucose, glycated hemoglobin, and homeostasis model assessment of insulin resistance in T2DM patients. Furthermore, many in vitro and in vivo experiments have found that ML is involved in various pathways that regulate glucolipid metabolism and resist diabetes while alleviating liver and kidney damage.

CONCLUSIONS

As a potential natural anti-diabetic phytomedicine, an in-depth study of ML can provide new ideas and valuable references for applying traditional Chinese medicine to treat T2DM. While continuously exploring its clinical efficacy and therapeutic mechanism, the extraction method should be optimized to improve the efficacy of the bioactive components. in addition, further research on the dose-response relationship of drugs to determine the effective dose range is required.

Unravelling the genetic potential for hydrocarbon degradation in the sediment microbiome of Antarctic islands

Hydrocarbons may have a natural or anthropogenic origin and serve as a source of carbon and energy for microorganisms in Antarctic soils. Herein, 16S rRNA gene and shotgun sequencing were employed to characterize taxonomic diversity and genetic potential for hydrocarbon degradation of the microbiome from sediments of sites located in two Antarctic islands subjected to different temperatures, geochemical compositions, and levels of presumed anthropogenic impact, named: Crater Lake/Deception Island (pristine area), Whalers Bay and Fumarole Bay/Deception Island (anthropogenic-impacted area), and Hannah Point/Livingston Island (anthropogenic-impacted area). Hydrocarbon concentrations were measured for further correlation analyses with biological data. The majority of the hydrocarbon-degrading genes were affiliated to the most abundant bacterial groups of the microbiome: Proteobacteria and Actinobacteria. KEGG annotation revealed 125 catabolic genes related to aromatic hydrocarbon (styrene, toluene, ethylbenzene, xylene, naphthalene, and polycyclic hydrocarbons) and aliphatic (alkanes and cycloalkanes) pathways. Only aliphatic hydrocarbons, in low concentrations, were detected in all areas, thus not characterizing the areas under study as anthropogenically impacted or nonimpacted. The high richness and abundance of hydrocarbon-degrading genes suggest that the genetic potential of the microbiome from Antarctic sediments for hydrocarbon degradation is driven by natural hydrocarbon occurrence.

The Determination of Polycyclic Aromatic Hydrocarbons (PAHs) with HPLC-DAD-FLD and GC-MS Techniques in the Dissolved and Particulate Phase of Road-Tunnel Wash Water: A Case Study for Cross-Array Comparisons and Applications

Accelerated solvent extraction (ASE) and solid phase extraction (SPE) protocols tailored to either gas chromatography mass spectrometry (GC-MS) or high-performance liquid chromatography coupled to diode-array and fluorescence detection (HPLC-DAD-FLD) were developed for the determination of EPA 16 polycyclic aromatic hydrocarbons (PAHs) in the particulate and dissolved phase of road-tunnel wash water. An analytical approach was developed, assessed, and applied on environmental samples collected from five road tunnels in Norway. The absolute recoveries ranged from 57 to 104% for the particulates, and from 42 to 79% for the dissolved water phase. The target PAH compounds were separated in 34.75 min using the GC method and in 22.50 min by HPLC. In the particulate phases, higher molecular weight PAHs were detected in the range of 0.043 to 0.93 µg/g, and lower molecular weight PAHs were detected in the range of 0.020 to 1.0 µg/g, while the intermediate ones were present in the range of 0.075 to 2.0 µg/g. In contrast to the particulates, the dissolved phase mainly contained lower molecular weight PAHs in the range of 0.0098 to 0.50 µg/L. GC-MS demonstrated lower detection limits (LODs) than HPLC-DAD-FLD for 13 out of the 16 PAHs. A cross-array comparison of the two analytical techniques indicated that some target PAHs were detected solely or in higher concentrations with HPLC-DAD-FLD, indicating the occurrence of false positive peaks or/and co-eluting components. The resulting concentrations in the road tunnel wash water samples were used to calculate specific PAH forensic ratios to pinpoint the potential sources of PAH pollution. These ratios revealed that there are several potential sources for the origin of PAHs in tunnel wash water.

Development of an online μ-matrix cartridge extraction method for fipronil extraction in contaminated soils

Nowadays, environment fate and behavior of pesticides in soil is still not fully understood due to the lack of standardized soil extraction method. In this work, a soil-filled micro-matrix cartridge was online combined with high performance liquid chromatography-mass spectrometry (HPLC-MS) through a six-way valve for the simultaneous extraction and determination of residual fipronil in soil. Compared with conventional extraction methods, such as hydroxypropyl-β-cyclodextrin (HPCD) extraction, shaking extraction, ultrasonic-assisted extraction (UAE), three-step extraction and matrix solid phase dispersion (MSPD), the novel, miniaturized, and integrated online micro-matrix cartridge extraction (online μ-MCE) method exhibited better performance in terms of desorption efficiency (99.4%), analysis time, solvent consumption, sensitivity, and automation. In sequential extraction, online μ-MCE could further desorb fipronil from the extracted soil with the percentage of 1.05%-58.55%. High recovery of 92.69% obtained for the ISO certificated test-soil verified the satisfactory accuracy of the method. Besides, its wide universality was also validated in three variables: 1) various pesticides-soil interactions, 2) four types of compounds (aromatic hydrocarbons, carboxylic acids, alcohols and aldehydes), and 3) three types of soils (sandy soil, silty loam and silty clay). The superior desorption capacity might be attributed to the instantaneously increased high-pressure, continuous flow dynamic desorption and short residence time. The present encouraging findings might shed light on new ways to develop a mild, highly efficient, reliable and one-fit-all extraction method toward pesticide contaminated soil.

Polycyclic aromatic hydrocarbon contamination in soils and sediments: Sustainable approaches for extraction and remediation

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic environmental pollutants that are extremely hydrophobic in nature and resistant to biological degradation. Extraction of PAHs from environmental matrices is the first and most crucial step in PAH quantification. Extraction followed by quantification is essential to understand the extent of contamination prior to the application of remediation approaches. Due to their non-polar structures, PAHs can be adsorbed tightly to the organic matter in soils and sediments, making them more difficult to be extracted. Extraction of PAHs can be achieved by a variety of methods. Techniques such as supercritical and subcritical fluid extraction, microwave-assisted solvent extraction, plant oil-assisted extraction and some microextraction techniques provide faster PAH extraction using less organic solvents, while providing a more environmentally friendly and safer process with minimum matrix interferences. More recently, more environmentally friendly methods for soil and sediment remediation have been explored. This often involves using natural chemicals, such as biosurfactants, to solubilize PAHs in contaminated soils and sediments to allow subsequent microbial degradation. Vermiremediation and microbial enzyme-mediated remediation are emerging approaches, which require further development. The following summarises the existing literature on traditional PAH extraction and bioremediation methods and contrasts them to newer, more environmentally friendly ways.

Soil washing for the remediation of dioxin-contaminated soil: A review

Dioxin-contaminated soil has attracted worldwide attention due to its potential negative impacts on human health and the ecosystem. Thus, technological development aiming at high treatment efficiency and low cost for dioxin-contaminated soil is largely needed. In this review, approximately 200 documents were involved to summarize up-to-date scientific achievements of soil washing technology for the remediation of dioxin-contaminated soil. The mechanisms, advantages, and limitations of physical separation techniques (e.g. mechanical stirring, mechanical shaking, ultrasonication, and froth flotation) and washing solutions (e.g. organic solvents, edible oils, and surfactants) used for chemical extraction were comprehensively reviewed. Froth flotation is very promising for field-scale soil washing, whereas organic solvents show high removal efficiencies (up to 99%) of dioxins from contaminated soil. Further, the combination of physical separation and chemical extraction can help enhance dioxin removal efficiency (from 1.5 to 2 times), reducing energy consumption and cost (about 2 times). Among available remediation technologies for dioxin-contaminated soil, soil washing is truly promising since it has shown high removal efficiency (66-99% different remediation scales) with reasonable cost (46 - 250 USD per metric ton). However, the washed solution and volatile organic compounds generated during the process remain a concern and should be addressed in future research.

A review on analysis methods, source identification, and cancer risk evaluation of atmospheric polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) have gained attention because of their environmental persistence and effects on ecosystems, animals, and human health. They are mutagenic, carcinogenic, and teratogenic. The review provides background knowledge about their sources, metabolism, temporal variations, and size distribution in atmospheric particulate matter. The review article briefly discusses the analytical methods suitable for the extraction, characterization, and quantification of nonpolar and polar PAHs, addressing the challenges. Herein, we discussed the molecular diagnostic ratios (DRs), stable carbon isotopic analysis (SCIA), and receptor models, with much emphasis on the positive matrix factorization (PMF) model, for apportioning PAH sources. Among which, DRs and PCA identified as the most widely employed method, but their accuracy for PAH source identification has received global criticism. Therefore, the review recommends compound-specific isotopic analysis (CSIA) and PMF as the best alternative methods to provide detailed qualitative and quantitative source analysis. The compound-specific isotopic signatures are not affected by environmental degradation and are considered promising for apportioning PAH sources. However, isotopic fractions of co-eluted compounds like polar PAHs and aliphatic hydrocarbons make the PAHs isotopic fractions interpretation difficult. The interference of unresolved complex mixtures is a limitation to the application of CSIA for PAH source apportionment. Hence, for CSIA to further support PAH source apportionment, fast and cost-effective purification techniques with no isotopic fractionation effects are highly desirable. The present review explains the concept of stable carbon isotopic analysis (SCIA) relevant to PAH source analysis, identifying the techniques suitable for sample extract purification. We demonstrate how the source apportioned PAHs can be applied in assessing the health risk of PAHs using the incremental lifetime cancer risk (ILCR) model, and in doing so, we identify the key factors that could undermine the accuracy of the ILCR and research gaps that need further investigation.

Getting a better overview of a highly PAH contaminated soil: A non-targeted approach assessing the real environmental contamination

Over the last 40 years, soils contaminated with polycyclic aromatic hydrocarbons (PAH) were monitored according to a list of 16 PAH, established by the U.S. Environmental Protection Agency (EPA). This, however, is underestimating the danger to the environment and humanity because other high molecular weight PAHs, heterocycles (PAXH, X = N, O, S) and alkylated derivatives can also occur at the contaminated site. Here, a new non-targeted approach of highly contaminated soil (64.5 ± 9.5 g kg^-1 solvent extractable organics from the German Ruhrgebiet) is introduced, where ultrahigh resolution mass spectrometry is combined with multiple ionization methods to get a better overview of anthropogenic contamination at a former industrial site. In total, 21,958 elemental compositions were assigned for positive and negative mode measurements. The approach is strongly increasing the amount of data that can be obtained from a single contaminated soil, making an assessment of the real environmental risk possible. In addition to highly aromatized and (alkylated) high molecular weight PAH, other PAXH especially basic and neutral PANH with very high aromaticity were also detected. This shows that while regulations and routine analysis are still stuck in the 1960 s, modern analytical methods are present in the 21st century.

Water-induced release of recalcitrant polycyclic aromatic hydrocarbons from soil organic matter during microwave-assisted solvent extraction

Polycyclic aromatic hydrocarbons (PAHs) in soil can be recalcitrant to solvent extraction after aging. We showed in this study that mixing a small amount of water in the extracting solvent during microwave-assisted extraction (MAE) can release recalcitrant PAHs, resulting in significant improvement in the analyzed concentrations. The improvement factor (F) for the total of 16 priority PAHs (∑PAH16) listed by the United States Environmental Protection Agency was 1.44-1.55 for field soils. By comparing the F values for different soil organic components, we demonstrated that the recalcitrant PAHs were primarily associated with biochar, humic acid (HA), and humin (HM), with the F values for ∑PAH16 of 1.94, 6.62, and 4.59, respectively. The results showed that the recalcitrant PAHs comprised a sequestered fraction and a desorption-limited fraction. NMR spectra showed that water worked alone at elevated temperature to promote hydrolysis of biochar and destroy the macromolecular structure, thus causing the release of the otherwise sequestered PAHs during MAE. The substantial reduction in F values for HA and HM after demineralization indicated sequestration of PAHs in organic-mineral complexes, which can be destroyed by hot water treatment. The release of the sequestered fraction was nonselective and independent of compound hydrophobicity. In comparison, the release of the desorption-limited fraction was positively affected by the hydrophobicity of PAHs and was facilitated by the presence of water in the extracting solvent. The results of this study provide important insights into the sequestration and release of recalcitrant PAHs in soil.

Ultrasound-assisted extraction of boulardii yeast cell wall polysaccharides: Characterization and its biological functions on early-weaned lambs

Firstly, this study was designed to determine the optimal ultrasound-assisted extraction parameters of Saccharomyces boulardii yeast wall polysaccharides (BYWP). Besides, the molecular weight and the ratio of mannose to glucose in compositions of BYWP were determined. Also, the effects of BYWP on the gain feed ratio, diarrhea frequency, intestinal morphology, intestinal immunity, and intestinal microbial flora of early-weaned lambs were investigated. Single-factor tests and Response surface optimization analysis (RSA) were used to obtain the optimal ultrasound-assisted extraction conditions. Sephadex G-100 column chromatography and liquid chromatography were used to analyze the molecular weight and ratio of mannose to glucose. The feeding trial was used to observe the biological functions of BYWP on early-weaned lambs. A total of 72 36-day-old crossbred early-weaned lambs were randomly divided into 4 groups with 3 replicates per group and 6 lambs per replicate. Lambs in the four treatments were fed basal milk replacer without supplement (Group I), basal milk replacer+0.1% BYWP (Group II), basal milk replacer+0.3% BYWP (Group III), and basal milk replacer+0.5% BYWP (Group IV), respectively. The optimal ultrasound-assisted extraction parameters were as follows: NaOH addition: 52.63%, ultrasonic power: 143.15 W, ultrasonic time: 86.20 min, and the optimized extraction yield reached 37.54%. The molecular weights of main components BLC-1 and BLC-2 were 164.68 KDa and 13.21 KDa, and their proportions in BYWP were 24.57% and 66.08%, respectively. The proportions of glucose, mannose in BLC-1 and BLC-2 were 47.68%, 39.18%, and 76.59%, 6.86%, respectively. The addition of 0.3% and 0.5% BYWP in basal milk replacer significantly increased the average daily gain and feed conversion rate, and decreased the average fecal index and diarrhea rate of early-weaned lambs. The addition of 0.3% and 0.5% BYWP significantly enhanced the intestinal morphology (villus height, crypt depth, and V/C value) of jejunum, ileum (p < .05). The addition of 0.3% and 0.5% BYWP significantly improved the levels of SIgA and IL-10, but significantly decreased the level of IL-1 in the ileum (p < .05). The addition of 0.3% and 0.5% BYWP significantly increased the number of Lactobacillus, but significantly suppressed the growth of Salmonella and Clostridium perfringens (p < .05). The results of the present study suggest that the supplementation of BYWP in the diet of early-weaned lambs could increase feed utilization rate, and enhance intestinal morphology, immunological competence, microbial flora balance, and decrease the rate of diarrhea occurrence.

Pesticide residues in agricultural topsoil from the Hainan tropical riverside basin: Determination, distribution, and relationships with planting patterns and surface water

Pesticide residues were assessed in rice-vegetable rotation topsoil from tropical riverside basin. The 256 tropical topsoil samples from the Nandu River Basin (NRB) and Wanquan River Basin (WRB) in Hainan (China) were taken from 2018 to 2019. A total of 32 current-use pesticides (CUPs) and nine legacy pesticides (LPs) were detected using a method based on a QuEChERS technique. The highest residues were from the fungicide carbendazim (257.2 μg/kg) and the insecticide imidacloprid (139.4 μg/kg). The nine LPs (8 organochlorine pesticides and chlorpyrifos) were detected in 84.4% of the samples with mean concentrations ranging from 0.02 to 675.4 μg/kg. The two most commonly detected pesticides were imidacloprid and emamectin benzoate with detection rates of 96.8% and 91.8%, respectively. The highest total concentration of pesticides from the NRB and WRB was detected in July. The highest average number of multi-residues (16) was recorded in January, compared to 14 and 12 in July and November, respectively. There was a significant correlation between the multiple pesticide residues in soil and vegetable planting types (p < 0.01). There was a significant positive correlation between the pesticide number in topsoil and the pesticide number in water (p < 0.01). The multiple pesticide residues found in surface water were consistent with those in topsoil, suggesting a potential risk of water contamination in the rice-vegetable rotation.

Physiological and biochemical responses of Amaranthus cruentus to polycyclic aromatic hydrocarbon pollution caused by thermal power units

Pollution due to release of polycyclic aromatic hydrocarbons from thermal power plants is a major global issue as the same is highly toxic and carcinogenic. The current research aims to investigate the responses of a dietary plant Amaranthus cruentus towards PAH pollution. For the said purpose, the plant was collected from agricultural land in close vicinity to thermal power units and the effects of PAH pollution on its chlorophyll and various nutraceutical content was evaluated. Oxidative stress biomarkers and antioxidant defense enzymes status and PAH accumulation was quantified as well. Real-time evidence of cell death, depletion of nutraceutical resources, and stomata configuration was generated through various histochemical studies and SEM analysis. Results indicated significant decline of chlorophyll a to the extent of 77% when compared to control. Oxidative stress markers, namely, superoxide radical, H₂O₂, and hydroxyl radical in pollution exposed plants were 12.7, 2.2, and 2.4 times respectively higher over the control which eventually resulted in 35% more cell death for the pollution exposed group. Total phenolics and flavonoids showed a decline of 57.6% and 41.3% respectively in the group exposed to PAH pollution. Similar decreasing trend was also observed for ascorbic acid, α-tocopherol, β-carotene, total proteins, and carbohydrate contents as well. PAH-induced stress also resulted in complete imbalance in the redox homeostasis of the plant which was evident from increase in super oxide dismutase, catalase, and peroxidase antioxidant enzymes by more than 2-fold when compared to control. PAH accumulation in sample group was 10-20 times more when compared to control. Proteomic analysis also indicated upregulation of some proteins related to stress situation. Results are evident of the fact that severe depletion of nutraceutical resources of dietary plants can take place if subjected to oxidative stress arising from PAH pollution.

Determination of non-extractable residues in soils: Towards a standardised approach

After exposure of soils to anthropogenic organic chemicals non-extractable residues (NER) can be formed. The quantitative proportion of a compound which remains non-extractable is operationally defined by the extraction procedure employed and can be quantified only when using isotope labelled compounds (e.g. ¹⁴C or ¹³C). In Germany and the EU, there is no standardised procedure, how to determine NER, especially when different legal regulations apply. Consequently, the comparability of NER data is low. Hence, a major task of this study was the development of a general approach for the quantification of non-extractable residues (NER) in soils using radiotracer analysis. For that, extraction efficiencies were determined for 42 non-labelled organic chemicals spiked onto 3 soils applying a number of extraction techniques and conditions, developing an extraction procedure which provides high extraction efficiencies and a low variability for a broad spectrum of analytes. Additionally, NER generated within soil transformation studies according to OECD 307 using ¹⁴C-triclosan, ¹⁴C-fenoxycarb and ¹⁴C-acetaminophen were analysed using sequential batch extraction and pressurised liquid extraction (PLE). Depending on the extraction procedure used, the NER fraction related to ¹⁴C-triclosan in a soil varied greatly between 96% and 28%. In this study a widely universal extraction procedure was developed to improve the comparability of the NER data and limit overestimation of NER, which can be of enormous consequence for the assessment of persistence and environmental risk of organic chemicals. Furthermore, silylation, EDTA-extraction and HCl-treatment were compared regarding a further analysis of NER using radiotracer analysis.

The difference in dissipation of clomazone and metazachlor in soil under field and laboratory conditions and their uptake by plants

The study concerned dissipation of metazachlor and clomazone, herbicides widely used in rapeseed (Brassica napus L. subsp. napus) protection, applied to the clay soil under field and laboratory conditions. Furthermore, the uptake of these pesticide from soil by rapeseed plants was investigated under field conditions. An additional aim of this work was to modify the QuEChERS method for the determination of metazachlor and clomazone in the plant material. Analytical procedures for metazachlor and clomazone qualification and quantification in rapeseed plants and soil were developed, using gas chromatography with an micro electron capture detector (GC-μECD) and a mass detector (GC-MS/MS QqQ) as confirmation. Dissipation kinetics of herbicide residues in soil were described as first-order equations. The analytical performance was very satisfactory and confirmed that the methods meet the requirements of the European Commission. In the conducted field experiments it was found that dissipation of clomazone and metazachlor in clay soil follows first-order kinetics (R2 between 0.964 and 0.978), and half-lives were 9.5 days and 10.2 days for clomazone and metazachlor, respectively. Under laboratory conditions, dissipation of clomazone and metazachlor in soil also follows first-order kinetics (R2 between 0.937 and 0.938), and half-lives were 8.8 days and 5.7 days for clomazone and metazachlor, respectively. Residues of both herbicides in rape plants 22 days after application of herbicides were below the maximum residue levels for Brassica plants. Metazachlor and clomazone dissipate very fast in clay soil and their uptake by rape plants is very low.

Bioavailability and metabolism in a soil-crop system compared using DGT and conventional extraction techniques

Traditional extraction methods (soil solution and solvent extraction) are simple to use and conventionally employed to assess pesticide chemical form and bioavailability in soils. However, whilst convenient for regulatory testing, it has been suggested that these approaches may be too crude or are poor predictors of bioavailability, due to their arbitrary original development to detect 'total' concentration using exhaustive extraction. The diffusive gradients in thin films (DGT) technique has been widely used to measure chemical speciation in situ and shown to reliably predict bioavailability of a range of contaminants (e.g. heavy metals, radionuclides, nutrients) in soil systems, because it dynamically samples contaminants from/re-supplied to the soil solution phase. Experiments were therefore conducted with 5 soils of different properties to compare DGT and the two conventional extraction approaches for sampling atrazine (ATR) and its metabolites from soils and for predicting their uptake by maize tissues. After 23 days aging, a large proportion of total ATR was still available for solvent (acetonitrile) extraction and the major constituent in soils was parent ATR. The best correlations of total ATR concentrations in maize and total ATR measured in soil were with DGT and soil solution measurements. This is encouraging, in jointly supporting one of the established methodologies traditionally used in pesticide testing (i.e. soil solution) and a widely used method (i.e. DGT), which has been validated previously for a range of contaminants. The poorer performance of solvent extraction (a procedure widely used for pesticide testing) is perhaps to be expected, given that solvents will not truly mimic the conditions encountered in soil-plant systems.

Natural Carbon By-Products for Transparent Heaters: The Case of Steam-Cracker Tar

Steam-cracker tar (SCT) is a by-product of ethylene production that is in massive quantities globally (>150 × 10⁶ tons per year). With few useful applications, the production of unwanted SCT leads to the need for its costly disposal or burning at the boiler plant. The discovery of new uses for SCT would therefore bring both economic and environmental benefits, although, to date, efforts toward employing SCT in diverse applications have been limited, and progress is further hampered by a lack of understanding of the material itself. Although complex and highly heterogeneous in nature, the molecular composition of SCT has the potential to serve as a diverse and tunable feedstock for wide-ranging applications. Here, a simple solution-processing method for SCT that allows its conductivity and optical properties to be controlled over orders of magnitude is reported. Here, by way of example, the focus is on the production of transparent conductive thin films, which exhibit a wide range of transparencies (23-93%) and sheet resistances (2.5 Ω □^-1 to 1.2 kΩ □^-1 ) that are tuned by a combination of solution concentration and thermal annealing. As transparent Joule heaters, even without optimization, these SCT devices show competitive performance compared to established technologies such as those based on reduced graphene oxide, and surpass the temperature stability limit of other materials. Furthermore, it is demonstrated that laser annealing can be used to process the SCT films and directly pattern transparent heaters on an arbitrary substrate. These results highlight the potential of SCT as a feedstock material for electronic applications and suggest that broader classes of either naturally occurring carbon or produced carbonaceous by-products could prove useful in a range of applications.

Development of an ASE-GC-MS/MS method for detecting dinitolmide and its metabolite 3-ANOT in eggs

An accelerated solvent extraction coupled with gas chromatography-tandem mass spectrometry (ASE-GC-MS/MS) method for detecting dinitolmide residue and its metabolite (3-amino-2-methyl-5-nitrobenzamide, 3-ANOT) in eggs was developed and optimized. The samples were extracted using ASE with acetonitrile as the extractant and were purified by passage through a neutral alumina solid-phase extraction column. Then, the samples were analyzed using the GC-MS/MS method. The optimized method parameters were validated according to the requirements set forth by the European Union and the Food and Drug Administration. The average recoveries of dinitolmide and 3-ANOT from eggs (egg white, egg yolk, and whole egg) at the limit of quantification (LOQ), 0.5 maximum residue limit (MRL), 1 MRL, and 2 MRL were 82.74% to 87.49%, the relative standard deviations (RSDs) were less than 4.63%, and the intra-day RSDs and the inter-day RSDs were 2.96% to 5.21% and 3.94% to 6.34%, respectively. The limits of detection and the LOQ were 0.8 to 2.8 μg/kg and 3.0 to 10.0 μg/kg, respectively. The decision limits (CC_α ) were 3001.69 to 3006.48 μg/kg, and the detection capabilities (CC_β ) were 3001.74 to 3005.22 μg/kg. Finally, the new method was successfully applied to the quantitative determination of dinitolmide and 3-ANOT in 50 commercial eggs from local supermarkets.

Bound PAHs in Sediment and Related Environmental Significance

Extractable polycyclic aromatic hydrocarbons (EPAHs) and bound PAHs (BPAHs) were measured in a sediment core using conventional Soxhlet extraction and a more astringent extraction method, with the objectives of determining the influence of BPAHs on the historical reconstruction of PAHs and exploring the formation of BPAHs and long-term behaviors of PAHs in sediment. The results indicated that the formation of BPAHs was clearly sediment-depth and molecular-size dependent. BPAHs represents an important portion of PAHs in sediment and cannot be extracted by conventional Soxhlet extraction. This suggests that the previously developed vertical profile of PAHs is not the real chronology of PAHs and the plausible interpretation derived from the sedimentary records of PAHs needs reexamination. Based on the previous findings, a biphase model was proposed and the formation of BPAHs was predicted. Due to the different nature of geosorbents in sediment, redistribution of PAHs among these geosorbents logically leads to the formation of BPAHs and is kinetically favorable for smaller molecular PAHs. This is consistent with the obtained results. Many factors may influence the formation of BPAHs, such as the physicochemical structure of sediment and environmental conditions. There is still a long way to reveal the thermodynamical characteristics in action during the formation of BPAHs.

Validation and uncertainty estimation of UPLC-PDA method for the analysis of polycyclic aromatic hydrocarbons in concrete

Human exposure to persistent organic contaminants, from building materials, negatively affects people's health and overall quality of life. This paper presents the validation and uncertainty assessment of the analytical method, developed for the simultaneous determination of 16 EPA polycyclic aromatic hydrocarbons (PAHs) in solid-solid concrete by ultra-performance liquid chromatography with photo diode-array detector. Linearity of calibration curves was good over the whole range of calibration. Limits of detection varied between 0.2 and 2.9μgkg^-1. The accuracy in terms of recovery of the validated method is within the range from 54 to 106%. The developed method proved to be appropriate for analysis of PAHs and can be used for the quality control testing of concrete during the construction of new buildings, the old residences and related buildings associated with sick-building syndrome. In addition, this is the first reported method described for the evaluation of PAHs in solid-solid concrete.

Distribution of polycyclic aromatic hydrocarbons in sediments of Akaki River, Lake Awassa, and Lake Ziway, Ethiopia

The quantification of 14 polycyclic aromatic hydrocarbons (PAHs) was carried out in sediment samples collected from Akaki River, Lake Awassa, and Lake Ziway, Ethiopia. The concentration of PAHs in the samples was determined using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode, after microwave-assisted extraction (MAE), using acetone/n-hexane (1:1, v/v) mixture. The accuracy of the method was determined by extracting and analyzing New York/New Jersey waterway sediment standard reference material (SRM 1944). The measured concentrations of PAHs in SRM 1944 agreed well with the certified values. In samples from Akaki River, Lake Awassa, and Lake Ziway, the total content of PAHs determined ranged from 0 to 3070 ng/g (average 534 ng/g), 24.9 to 413 ng/g (average 169 ng/g), and 15.0 to 305 ng/g (average 175 ng/g), respectively. Source ratios indicated that the PAHs were mainly from petrogenic origin. Sediments from all sampling sites indicated negligible levels of toxicity with no risk of adverse biological effects.

Characteristics of polycyclic aromatic hydrocarbons in agricultural soils at a typical coke production base in Shanxi, China

There is wide concern about polycyclic aromatic hydrocarbons (PAHs) because of their carcinogenic and mutagenic potential. The coking industry is an important source of PAHs. In this study, 36 arable soil samples, a sensitive medium from the perspective of food safety and health, were collected from one of the largest coke production bases in China. The concentration of total 21 PAHs ranged from 294 to 1665 ng g(-1), with a mean of 822±355 ng g(-1). Approximately 60% of the soil samples were heavily polluted with the level higher than 600 ng g(-1). Particularly high abundances of high molecular weight PAHs were found, and the calculated BaPeq was as high as 54.3 ng g(-1). Soil PAH levels were positively correlated with soil organic matter content. The soil PAHs were from complex mixture sources, and high-temperature pyrogenic sources were most likely responsible for the heavy PAH contamination. Effective control strategies and probable remediation approaches should be proposed to improve soil quality.

Concentrations and origins of nitro-polycyclic aromatic hydrocarbons and oxy-polycyclic aromatic hydrocarbons in ambient air in urban and rural areas in northern China

Twelve nitro-PAHs (nPAHs) and four oxy-PAHs (oPAHs) were measured in air samples for 12 months at 18 sites in urban settings, rural villages, or rural fields in northern China. The nPAH concentrations were higher in urban areas (1.3 ± 1.3 ng/m(3)), and nPAH/parent PAH ratios were higher (suggesting important contributions from motor vehicles and secondary formation) in urban sites than in rural villages. oPAHs are primarily emitted from solid fuel combustion and motor vehicles, and similar oPAH concentrations were found in urban areas (23 ± 20 ng/m(3)) and rural villages (29 ± 24 ng/m(3)). The high numbers of motor vehicles in Beijing and intensive industrial activity in Taiyuan and Dezhou caused higher nPAH concentrations. No spatial trend in oPAH concentrations was found in the rural villages, because similar oPAH mixtures are emitted from solild fuel combustion. The nPAH and oPAH concentrations were higher in the winter, and correlated with residential energy consumption and precipitation.