Fabrication of imidazoline-linked cationic covalent triazine framework for enrichment of environmental estrogens

Imidazoline-linked cationic covalent triazine framework (IM-iCTF) was facilely prepared through the Debus-Radziszewski reaction, involving 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline, formaldehyde and methylglyoxal. The IM-iCTF was applied as a sorbent for cartridge solid-phase extraction (SPE). It provided good adsorption performance for estrogen and estrogen mimics including bisphenol F, bisphenol A, 7β-estradiol, bisphenol B and estrone. The adsorption isotherm, adsorption kinetic model, thermodynamic calculations and adsorption mechanism were investigated to reveal the adsorption behavior. The IM-iCTF was employed for the extraction of the estrogens and estrogen mimics from water, fish and shrimp (fish and shrimp samples were extracted with acetonitrile before the SPE). The analytes were then determined by high-performance liquid chromatography with diode array detection. The limits of detection were 0.008-0.05 ng mL-1 for water, 0.015-0.11 μg g-1 for fish, and 0.012-0.10 μg g-1 for shrimp samples. This research not only offers a new approach to construct cationic covalent triazine framework, but also provides a reliable strategy for the adsorption/enrichment trace level of organic pollutants.

Mechanistic insight into biotransformation of novel triazine-based flame retardant 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazinane-2,4,6-trione by human cytochrome P450s

The escalating focus on the environmental occurrence and toxicology of emerging pollutants underscores the imperative need for a profound exploration of their metabolic transformations mediated by human CYP450 enzymes. Such investigations have the potential to unravel the intricate metabolite profiles, substantially altering the toxicological outcomes. In this study, we integrated the computational simulations with in vitro metabolism experiments to investigate the metabolic activity and mechanism of an emerging pollutant, 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazinane-2,4,6-trione (TDBP-TAZTO), catalyzed by human CYP450s. The results highlight the important contributions of CYP2E1, 3A4 and 2C9 to the biotransformation of TDBP-TAZTO, leading to the identification of four distinct metabolites. The effective binding conformations governing biotransformation reactions of TDBP-TAZTO within active CYP450s are unveiled. Structural instability of primary hydroxyTDBP-TAZTO products suggests three potential outcomes: (1) generation of an alcohol metabolite through successive debromination and reduction reactions, (2) formation of a dihydroxylated metabolite through secondary hydroxylation by CYP450, and (3) production of an N-dealkylated metabolite via decomposition and isomerization reactions in the aqueous environment. The formation of a desaturated debrominated metabolite may arise from H-abstraction and barrier-free Br release during the primary oxidation, potentially competing with the generation of hydroxyTDBP-TAZTO. These findings provide detailed mechanistic insight into TDBP-TAZTO biotransformation by CYP450s, which can enrich our understanding of the metabolic fate and associated health risk of this chemical.

Rapid detection of melamine by DNA Walker mediated SERS sensing technique based on signal amplification function

A new method is proposed for detecting typical melamine dopants in food using surface-enhanced Raman scattering (SERS) biosensing technology. Melamine specific aptamer was used as the identification probe, and gold magnets (AuNPs@MNPs) and small gold nanoparticles (AuNPs@MBA) were used as the basis for Raman detection. The Raman signal of the detection system can directly detect melamine quantitatively. Under optimized conditions, the detection of melamine was carried out in the low concentration range of 0.001-500 mg/kg, the enhancement factor (EF) was 2.3 × 107, and the detection limit was 0.001 mg/kg. The method is sensitive and rapid, and can be used for the rapid detection of melamine in the field environment.

Occurrence and Ecological Risk of Alkylamine Triazines in Chinese Estuarine Sediments: An Emerging Class of Persistent, Mobile, and Toxic Substances

Identifying persistent, mobile, and toxic (PMT) substances from synthetic chemicals is critical for chemical management and ecological risk assessment. Inspired by the triazine analogues (e.g., atrazine and melamine) in the original European Union's list of PMT substances, the occurrence and compositions of alkylamine triazines (AATs) in the estuarine sediments of main rivers along the eastern coast of China were comprehensively explored by an integrated strategy of target, suspect, and nontarget screening analysis. A total of 44 AATs were identified, of which 23 were confirmed by comparison with authentic standards. Among the remaining tentatively identified analogues, 18 were emerging pollutants not previously reported in the environment. Tri- and di-AATs were the dominant analogues, and varied geographic distributions of AATs were apparent in the investigated regions. Toxic unit calculations indicated that there were acute and chronic risks to algae from AATs on a large geographical scale, with the antifouling biocide cybutryne as a key driver. The assessment of physicochemical properties further revealed that more than half of the AATs could be categorized as potential PMT and very persistent and very mobile substances at the screening level. These results highlight that AATs are a class of PMT substances posing high ecological impacts on the aquatic environment and therefore require more attention.

Mechanistic interpretation of the sorption of terbuthylazine pesticide onto aged microplastics

Microplastics (MPs) pose a global concern due to their ubiquitous distribution. Once in the environment, they are subject to aging, which changes their chemical-physical properties and ability to interact with organic pollutants, such as pesticides. Therefore, this study investigated the interaction of the hydrophobic herbicide terbuthylazine (TBA), which is widely used in agriculture, with artificially aged polyethylene (PE) MP (PE-MP) to understand how aging affects its sorption. PE was aged by an accelerated weathering process including UV irradiation, hydrogen peroxide, and ultrasonic treatment, and aged particles were characterized in comparison to pristine particles. Sorption kinetics were performed for aged and pristine materials, while further sorption studies with aged PE-MP included determining environmental factors such as pH, temperature, and TBA concentration. Sorption of TBA was found to be significantly lower on aged PE-MP compared to pristine particles because aging led to the formation of oxygen-containing functional groups, resulting in a reduction in hydrophobicity and the formation of negatively charged sites on oxidized surfaces. For pristine PE-MP, sorption kinetics were best described by the pseudo-second-order model, while it was intra-particle diffusion for aged PE-MP as a result of crack and pore formation. Sorption followed a decreasing trend with increasing pH, while it became less favorable at higher temperatures. The isotherm data revealed a complex sorption process on altered, heterogeneous surfaces involving hydrophobic interactions, hydrogen bonding, and π-π interactions, and the process was best described by the Sips adsorption isotherm model. Desorption was found to be low, confirming a strong interaction. However, thermodynamic results imply that increased temperatures, such as those resulting from climate change, could promote the re-release of TBA from aged PE-MP into the environment. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) confirmed TBA sorption onto PE.

May 1,3,5-Triazine derivatives be the future of leather tanning? A critical review

Leather is produced by a multi-step process among which the tanning phase is the most relevant, transforming animal skin collagen into a stable, non-putrescible material used to produce a variety of different goods, for the footwear, automotive, garments, and sports industry. Most of the leather produced today is tanned with chromium (III) salts or alternatively with aldehydes or synthetic tannins, generating high environmental concern. Over the years, high exhaustion tanning systems have been developed to reduce the environmental impact of chromium salts, which nevertheless do not avoid the use of metals. Chrome-free alternatives such as aldehydes and phenol based synthetic tannins, are suffering from Reach restrictions due to their toxicity. Thus, the need for environmentally benign and economically sustainable tanning agents is increasingly urgent. In this review, the synthesis, use and tanning mechanism of a new class of tanning agents, 1,3,5-triazines derivatives, have been reported together with organoleptic, physical mechanical characteristics of tanned leather produced. Additionally environmental performance and economic data available for 1,3,5-triazines have been compared with those of a standard basic chromium sulphate tanning process, evidencing the high potentiality for sustainable, metal, aldehyde, and phenol free leather manufacturing.

Qualitative and semi-quantitative analysis of melamine in liquid milk based on surface-enhanced Raman spectroscopy

Melamine is one of the common limited contaminations in dairy products. The traditional detection method has a long period and complicated pretreatment process. The rapid detection method is the better method to solve the screening of limited contaminations. In this paper, taking melamine as the research object, the surface enhanced Raman spectrum of melamine in liquid milk were collected by portable Raman spectrometer, and melamine was qualitatively identified and semi-quantitatively analyzed by Raman characteristic peak and Raman intensity, and a simple and efficient rapid screening method for limited contaminations was developed. The limit of detection is 0.25 mg/kg. The probability of detection is 100% at 2.5 mg/kg, which is the same between the two laboratories, indicating that the semi-quantitative method has good repeatability. The method of melamine proposed in this study can meet the rapid screening requirements of limited contaminations at the maximum residue limit, and has a good application prospect.

Occurrence, distribution, and risk assessment of pesticides in surface water and sediment in Jiangsu Province, China

The occurrence and distribution of 157 pesticides were investigated in surface water and sediment in Jiangsu Province, China. Gas chromatography-mass spectrometry was used to analyze and quantify these pesticides, and the risk quotient method was used to evaluate their respective environmental risk. The results showed that 91 pesticides were detected in surface water. The organophosphates (OPPs), fungicides, and amide herbicides were predominant. The total concentration in surface water ranged from 63.7 to 22,463 ng/L, 3.90 to 7262 ng/L, and ND to 34,120 ng/L, respectively. The mean concentration was 3479 ng/L, 1644 ng/L, and 1878 ng/L, respectively. The concentration range of detected pesticides in the Yangtze River Basin was generally lower than that in the Huai River Basin. In sediment samples, a total of 63 pesticides were detected. OPPs and amide herbicides were also ranked highest; the total concentration in sediment samples ranged from 2951 to 47,739 ng/g and 106 to 12,996 ng/g, respectively. And the mean concentrations was 6971 ng/g and 5130 ng/g, respectively. Suqian City had the highest concentration for OPPs and amide herbicides in the Huai River Basin, followed by Huai'an City, while Nanjing City and Yangzhou City ranked highest in the Yangtze River Basin. The spatial distribution of pesticides in Jiangsu Province indicated a concentration significantly higher in the western and northern regions than in the eastern and southern regions, and a concentration generally higher in lakes than in rivers. The risk assessment results showed that OPPs, fungicides, amide herbicides, organochlorines, and triazine herbicides in most surface water samples posed a high risk and had regional pollution characteristics. In sediment samples, organochlorines, carbamates, other herbicides, and other insecticides posed a high risk in northern Jiangsu Province, whereas OPPs, amide herbicides, and triazine herbicides posed high risks everywhere in Jiangsu Province.

Behavioural, developmental and biochemical effects in zebrafish caused by ibuprofen, irgarol and terbuthylazine

The increasing use of chemicals and their release into aquatic ecosystems are harming aquatic biota. Despite extensive ecotoxicological research, many environmental pollutants' ecological effects are still unknown. This study examined the spatial avoidance, behavioural and biochemical impacts of ibuprofen, irgarol, and terbuthylazine on the early life stages of zebrafish (Danio rerio) under a range of ecologically relevant concentrations (0-500 μg/L). Embryos were exposed following the OECD guideline "fish embryo toxicity test" complemented with biochemical assessment of AChE activity and behavioural analyses (swimming activity) using the video tracking system Zebrabox. Moreover, spatial avoidance was assessed by exposing 120 hpf-old larvae of D. rerio to a gradient of each chemical, by using the heterogeneous multi-habitat assay system (HeMHAS). The results obtained revealed that the 3 compounds delayed hatching at concentrations of 50 and 500 μg/L for both ibuprofen and irgarol and 500 μg/L for terbuthylazine. Moreover, all chemicals elicited a dose-dependent depression of movement (swimming distance) with LOEC values of 5, 500 and 50 μg/L for ibuprofen, irgarol and terbuthylazine, respectively. Zebrafish larvae avoided the three chemicals studied, with 4 h-AC50 values for ibuprofen, irgarol, and terbuthylazine of 64.32, 79.86, and 131.04 μg/L, respectively. The results of the HeMHAS assay suggest that larvae may early on avoid (just after 4 h of exposure) concentrations of the three chemicals that may later induce, apical and biochemical effects. Findings from this study make clear some advantages of using HeMHAS in ecotoxicology as it is: ecologically relevant (by simulating a chemically heterogeneous environmental scenario), sensitive (the perception of chemicals and the avoidance can occur at concentrations lower than those producing lethal or sublethal effects) and more humane and refined approach (organisms are not mandatorily exposed to concentrations that can produce individual toxicity).

Explosives removal and quantification using porous adsorbents based on poly(2-oxazoline)s with various degree of functionalization

Polymeric porous adsorbents are reported for removal of explosives, namely picric acid, 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN) and their subsequent quantification using direct analysis with ambient plasma mass spectrometry. The adsorbents are obtained by functionalization of short-chain poly(2-oxazoline)s with methyl ester side chains using 4-(aminomethyl)pyridine with a degree of functionalization equal to 0, 5, 10, and 20%. The subsequent step consist of cross-linking using a high internal phase emulsion procedure by further side-chain amidation with diethylenetriamine as crosslinker. Picric acid, RDX, and PETN were chosen as the model compounds as they belong to three different groups of explosives, in particular nitroaromatics, nitroamines, and nitrate esters, respectively. The adsorption isotherms, kinetics, as well as the influence of pH and temperature on the adsorption process was investigated. The porous adsorbents showed the highest maximum adsorption capacity towards picric acid, reaching 334 mg g-1, while PETN (80 mg g-1) and RDX (17.4 mg g-1) were less efficiently adsorbed. Subsequent quantification of the adsorbed explosives is performed by a specially designed ambient mass spectrometry setup equipped with a thermal heater. The obtained limits of detection were found to be 20-times improved compared to direct analysis of analyte solutions. The effectiveness of the proposed analytical setup is confirmed by successful quantification of the explosives in river water samples. The research clearly shows that functional porous adsorbents coupled directly with ambient mass spectrometry can be used for rapid quantification of explosives, which can be, e.g., used for tracking illegal manufacturing sites of these compounds.

Tris(2,3-dibromopropyl)Isocyanurate has an Effect on Inflammation Markers in Mouse Primary Astrocytes In vitro

Tris(2,3-dibromopropyl)isocyanurate (TBC or TDBP-TAZTO) is a new brominated flame retardant (BFR) used as a replacement of classic BFR, such as tetrabromobisphenol A. TBC is supposed to be safer than classic BFRs, but reports show that it may induce a similar toxic effect. Therefore, the aim of the present study was to determine the impact of TBC on the inflammation and activation of the apoptosis process in mouse cortical astrocytes in vitro. Our results have shown that TBC increases caspase-1 and caspase-3 activity in mouse astrocytes in vitro, which suggests inflammation-induced apoptosis. Further analyses have revealed that TBC indeed increases the level of inflammation markers, e.g. Cat, IL-1β and IL-1βR1 proteins, but decreases the level of proliferation marker protein Ki67. However, our study has demonstrated that TBC does not change the morphology of astrocytes and does not increase the number of apoptotic bodies - a well-established marker of late apoptosis. Moreover, the concentration of 50 µM TBC also increases caspase-3 activity with no formation of apoptotic bodies. However, since 10 and 50 µM TBC have never been detected in living organisms, we can assume that the compound is safe at the low concentrations that are detected.

Occurrence, fate, seasonal variability, and risk assessment of twelve triazine herbicides and eight related derivatives in source, treated, and tap water of Wuhan, Central China

Triazine herbicides have been widely used, are frequently detected in aqueous environments and soils, and can cause acute or chronic toxicity to living organisms. We collected source water samples (n = 20) originating from the Hanshui River and the Yangtze River of Wuhan section, treated water samples (n = 20), and tap water samples (n = 169) in Wuhan, Central China during 2019 for determination of twelve triazine herbicides and their eight derivatives (collectively defined as TZs) and characterizing their fate during water treatment. Eighteen of the twenty TZs were detected in the source water. Atrazine (ATZ) had the highest concentrations (median: 22.4 ng/L) in the source water samples while DACT had the highest concentrations (median: 31.4 ng/L) in the treated water. "Tryns" (ametryn, prometryn, simetryn, terbutryn) were efficiently removed by conventional water treatment, while other target analytes were not; interestingly, hydroxypropazine and prometon increased significantly accompanied by prometryn disappearance, which implicated potential transformation pathways. In addition, "tryns" might be transformed into "tons" (atraton, prometon, secbumeton, terbumeton) by ozonation. In the tap water samples, diaminochlorotriazine had the highest concentrations (median: 34.9 ng/L) among the target analytes, followed by ATZ (18.3 ng/L), hydroxyatrazine (5.17 ng/L), deethylatrazine (5.00 ng/L), hydroxypropazine (3.20 ng/L), deisopropylatrazine (2.05 ng/L), hydroxydesethylatrazine (1.68 ng/L), and others. The TZs had the highest cumulative concentration in July in the tap water samples (median: 89.7 ng/L). This study found that ozonation in combination with activated carbon was more efficient in removing triazine herbicides, although "tryns" could also be transformed during conventional treatment. Ecological risk assessment showed moderate risks posed by hydroxyterbuthylazine, prometryn, and simetryn; the Hanshui River had higher risks than the Yangtze River, and July had higher risks than February. Human exposure to the TZs via water ingestion was low compared to the reference doses. This study characterized the occurrence of some new emerging TZs in the source water, their fate during drinking water treatment, and their seasonal variability in the tap water.

Melamine in Iranian foodstuffs: A systematic review, meta-analysis, and health risk assessment of infant formula

The presence of melamine in food is one of the most significant threats to consumer health and food safety now confronting the communities. The goal of this systematic review and meta-analysis was to determine the melamine content of different food products available on the Iranian market. The pooled melamine concentration (95% confidence interval) on 484 samples of animal-based foodstuffs was as follows: 0.22 (0.08, 0.36 mg kg^-1) for milk, 0.39 (0.25, 0.53 mg kg^-1) for coffee mate, 1.45 (1.36, 1.54 mg kg^-1) for dairy cream, 0.90 (0.50, 1.29 mg kg^-1) for yoghurt, 1.25 (1.20, 1.29 mg kg^-1) for cheese, 0.81 (-0.16, 1.78 mg kg^-1) for hen eggs, 1.28 (1.25, 1.31 mg kg^-1) for poultry meat, 0.58 (0.35, 0.80 mg kg^-1) for chocolates, and 0.98 (0.18, 1.78 mg kg^-1) for infant formula. Based on the results of health risk assessment study on toddlers under 2 years old who ingested infant formula (as a melamine-sensitive group), all groups of toddlers are at an acceptable level of non-carcinogenic risk (THQ ≤ 1). Toddlers were classified according to their ILCR (carcinogenic risk) levels due to infant formula consumption as follows: under 6 months (0.0000056), 6-12 months (0.0000077), 12-18 months (0.0000102), and 18-24 months (0.0000117). The melamine carcinogenicity in infant formula for children had an ILCR value of 0.000001-0.0001 in the investigation, which was considerable risk. According to the findings, Iranian food products (notably infant formula) should be analyzed for melamine contamination on a regular basis.

Spatial and seasonal distribution of pesticides in the waters of Azagny area (Grand Lahou, Cote d'Ivoire)

This study provides comprehensive data on the seasonal variation and distribution of pesticides in the waters bordering Azagny National Park (ANP). Forty-six (46) samples of water from the Azagny area were analyzed using high-performance liquid chromatography (HPLC) coupled with a UV/visible detector to assess the level of thirty-one pesticide molecules divided into six families. These include triazines, phenylureas, organophosphates, carbamates, chloroacetanilides, dicarboximides, and crimidine, which are regularly used in this area. The respective average concentrations of pesticides are 54.54 µg//L, 20.93 µg/L, 18.24 µg/L, 3.06 µg/L, and 16.52 µg/L in the Bandama, Azagny Canal, ANP, mangroves, and estuarine environment. The analyses also showed that herbicides were the most abundant pesticides in the three waters, Bandama, Azagny Canal, and Azagny Park, with levels of 100%, 63%, and 59%, respectively, followed by insecticides with a levels of 0%, 37%, and 41%, respectively. However, rodenticides (76%) were more frequently detected than herbicides (24% in the mangroves). Regarding seasonal variation, high levels of pesticides were detected in the Bandama River, the Azagny Canal, and the mangroves during the dry season, while multiple pesticide residues were detected during the rainy season. The waters bordering Azagny National Park (ANP) are contaminated with pesticide residues (triazines, phenylureas, organophosphates, carbamates, and chloroacetanilides). As a result, policymakers should implement measures to regularly monitor pesticide levels in plantations surrounding the Azagny region's waters in order to better preserve biodiversity.

Antifouling booster biocides in Latin America and the Caribbean: A 20-year review

This review summarized booster biocides studies from Latin America and the Caribbean during the last two decades. Studies were focused on six countries, with most of them in Brazil. In water and sediment, diuron and Irgarol were the most abundant and frequent biocides, probably due to their former intense use. Antifouling paint particles were also reported and had mainly DCOIT, which is currently the most used booster biocide. Toxicity of individual booster biocides was tested in laboratory, and most effects were related to chlorothalonil, DCOIT, dichlofluanid, and Irgarol, including, but not limited to DNA damage, fertility decrease, and mortality at different trophic levels. This review highlighted the need for further studies on environmental occurrence of booster biocides in Latin America and Caribbean associated to ecotoxicological studies. Such information is essential to determine the potential ecological risks and to create directives regarding safe limits of booster biocides in aquatic systems.

Facile synthesis of triazine-based porous organic polymer for the extraction and determination of nitrofuran metabolites residues from meat samples with ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry

In this work, a novel triazine-based porous organic polymers, TAPT-BPDD, was firstly synthesized by a facile method at room temperature. After characterized by FT-IR, FE-SEM, XRPD, TGA, and nitrogen-sorption experiments, TAPT-BPDD was applied as solid-phase extraction (SPE) adsorbent for the extraction of four trace nitrofuran metabolites (NFMs) from meat samples. The key parameters including the adsorbent dosage, sample pH, type and volume of eluents, type of washing solvents were evaluated in the extraction process. Combined with ultra-high performance liquid chromatography-quadrupole time of flight mass spectrometry (UHPLC-QTOF-MS/MS) analysis, good linear relationship (1-50 µg·kg^-1, R²>0.9925) and low limits of detection (LODs, 0.05-0.56 µg·kg^-1) were obtained under the optimal conditions. When spiked at different level, the recoveries were in the range of 72.7-111.6%. The adsorption isothermal model and extraction selectivity of TAPT-BPDD were also studied in detail. The results showed that TAPT-BPDD was a kind of promising SPE adsorbent for the enrichment of organics in food samples.

Bioinformatics analysis of the potential mechanisms of Alzheimer's disease induced by exposure to combined triazine herbicides

BACKGROUND

The development of Alzheimer's disease (AD) is promoted by a combination of genetic and environmental factors. Notably, combined exposure to triazine herbicides atrazine (ATR), simazine (SIM), and propazine (PRO) may promote the development of AD, but the mechanism is unknown.

AIM

To study the molecular mechanism of AD induced by triazine herbicides.

METHODS

Differentially expressed genes (DEGs) of AD patients and controls were identified. The intersectional targets of ATR, SIM, and PRO for possible associations with AD were screened through network pharmacology and used for gene ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis. The binding potentials between the core targets and herbicides were validated by molecular docking and molecular dynamics.

RESULTS

A total of 1,062 DEGs were screened between the AD patients and controls, which identified 148 intersectional targets of herbicides causing AD that were screened by network pharmacology analysis. GO and KEGG enrichment analysis revealed that cell cycling and cellular senescence were important signalling pathways. Finally, the core targets EGFR, FN1, and TYMS were screened and validated by molecular docking and molecular dynamics.

CONCLUSION

Our results suggest that combined exposure to triazine herbicides might promote the development of AD, thereby providing new insights for the prevention of AD.

Presence and distribution of triazine herbicides and their effects on microbial communities in the Laizhou Bay, Northern China

This study investigated the distribution of triazine herbicides in the Laizhou Bay, China and found that the total concentrations of triazine herbicides in the seawater and sediments were 111.15-234.85 ng/L and 0.902-4.661 μg/kg, respectively. Triazine herbicides especially ametryn, atrazine, and simazine were negatively correlated with prokaryote diversity in the seawater. While ametryn, desethylatrazine and desisopropylatrazine had positively significant effects on eukaryotes Dinophyceae, Bacillariophyta, and Cercozoa in the sediments. Moreover, the degree of fragmentation of eukaryotic networks increased dramatically with the increasing numbers of removed nodes, but prokaryotic networks did not change with the decrease of nodes. In addition, the stability analysis and neutral community models revealed that eukaryotes were more sensitive to triazine herbicides than prokaryotes. These results suggest that triazine herbicides might affect the structure and interactions of microbial communities. Therefore, more attentions should be paid to the ecological risk of triazine herbicides in marine ecosystems.

Hydrophobic microporous extraction on polyurethane sponges for convenient and sensitive analysis of organic molecules in water

RATIONALE

Various solvent supports have been developed to overcome solvent instability during liquid-phase microextraction. The hydrophobic polyurethane sponge (PS) possesses numerous cross-linked internal microchannels and terminal micropores that can facilitate steady solvent storage capacity, high extraction efficiency, extractant loading, and recycling convenience.

METHODS

In this study, an easy, convenient, and efficient PS-supported liquid-phase microextraction (PS-LPME) coupled with gas chromatography-mass spectrometry (GC-MS) method was developed for the trace analysis of different organic compounds in aqueous solutions. Different extraction solvents, PS dosages, stirring speeds, and extraction times were first investigated by extracting eight polycyclic aromatic hydrocarbons (PAHs: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene), and then applied for the analysis of triazines, amides, chloroacetamides, and organophosphorus compounds.

RESULTS

High enrichment factors (approximately 208-439) were observed for the monitored PAHs. Good linearities, with determination coefficients (r² ) greater than 0.9992, were achieved in the concentration range of 0.01-50 μg L^-1 . Low limits of detection and quantification were found in the ranges of 0.3-3 ng L^-1 and 1-10 ng L^-1 , respectively. At three spiked concentrations (0.1, 1, and 10 μg L^-1 ), good recoveries were obtained in the range of 91.6-118.5% with intra- and inter-day relative standard deviations of less than 6.4% and 11.7%, respectively.

CONCLUSIONS

The developed PS-LPME method coupled with GC-MS was successfully applied in the analysis of different organic compounds in aqueous solutions and has shown great convenience and satisfactory enrichment performance in microextraction analysis.

Analytical research of pesticide biomarkers in wastewater with application to study spatial differences in human exposure

Wastewater-based epidemiology (WBE) relies on the assessment and interpretation of levels of biomarkers in wastewater originating from a well-defined community. It has provided unique information on spatial and temporal trends of licit and illicit drug consumption, and has also the potential to give complementary information on human exposure to chemicals. Here, we focus on the accurate quantification of pesticide biomarkers (i.e., predominantly urinary metabolites) in influent wastewater at the ng L^-1 level to be used for WBE. In the present study, an advanced analytical methodology has been developed based on ultra-high-pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS), for the simultaneous determination of 11 specific human biomarkers of triazines, urea herbicides, pyrethroids and organophosphates in urban wastewater. The sample treatment consisted of solid-phase extraction using Oasis HLB cartridges. Direct injection of the samples was also tested for all compounds, as a simple and rapid way to determine these compounds without sample manipulation (i.e., minimizing potential analytical errors). However, if extraction recoveries are satisfactory, SPE is the preferred approach that allow reaching lower concertation levels. Six isotopically labelled internal standards were evaluated and used to correct for matrix effects. Due to the difficulties associated with this type of analysis, special emphasis has been placed on the analytical challenges encountered. The satisfactory validated methodology was applied to urban wastewater samples collected from different locations across Europe revealing the presence of 2,6-EA, 3,4-DCA, 3-PBA and 4-HSA i.e, metabolites of metolachlor-s, urea herbicides, pyrethroids and chlorpropham, respectively. Preliminary data reported in this paper illustrate the applicability of this analytical approach for assessing human exposure to pesticides through WBE.

[Determination of three penicillin residues in milk by solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry using a covalent triazine framework sorbent]

A method based on solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) was established for the determination of gpenicillin, cloxacillin, ampicillin residues in milk. Using self-made covalent triazine frameworks (CTFs) as the solid-phase extraction sorbents, the main factors influencing the efficiency of the solid-phase extraction columns, such as the sorbent amount, eluent type, eluent volume, and flow rate, were optimized. The extraction and purification conditions for the samples were also investigated. The optimal extraction effect was achieved at a flow rate of 3 mL/min with 60 mg CTFs and 6 mL eluent solution (acetonitrile). Separation was carried out on a Waters ACQUITY UPLC BEH C18 column, and 0.1% formic acid aqueous solution-acetonitrile was used as the mobile phases for gradient elution. The filtrate was detected by ultra performance liquid chromatography-tandem mass spectrometry, identified by electrospray ionization (ESI) in the positive mode using multiple reaction monitoring, and quantified using external standards. The calibration curves of the three penicillins showed good linearity and the correlation coefficients of the linear regression equations for the three target analytes were all greater than 0.999. The limits of detection (LODs) and limits of quantification (LOQs) were 0.05-0.10 μg/kg and 0.1-0.4 μg/kg, respectively. The average recoveries of the three analytes were 84.9%-94.1%, and the relative standard deviations (RSDs, n=5) were 1.66%-3.27%. Moreover, the mechanism of interaction between the CTFs and the target analytes was analyzed. The results revealed the existence of π-π and hydrogen-bond interactions between the CTFs and analytes. The results further indicated that the CTFs could be successfully used for the enrichment and purification of penicillins in milk. The proposed method has the advantages of high precision, good reproducibility, high resolution, and short analysis time, and it is suitable for the qualitative and quantitative determination of trace targets in complex matrices.

Novel triazine-based cationic covalent organic polymers for highly efficient and selective removal of selenate from contaminated water

Selenium (Se) removal from contaminated water has become a major environmental problem in recent years. Designing efficient and selective materials for selenium adsorption is urgent and still represents a great challenge. Herein, two novel cationic covalent triazine frameworks (CTFS-Cl and CTFL-Cl) are developed for the first time and employed as a new class of Se adsorbents. The results from systematic adsorption experiments indicate that these materials can adsorb SeO₄^2- in a wide range of pH values (2-11) with fast kinetics (5 min), outstanding adsorption capacity, and excellent selectivity over other competing anions. The maximum adsorption capacity achieved (149.3 mg/g by CTFS-Cl) constitutes one of the highest values among the organic polymeric materials. More importantly, after a single step adsorption, these materials can reduce the Se concentrations to lower than 10 μg/L, the lowest drinking water standard in the world. The adsorption mechanism was probed by XPS technique, EDS analysis, adsorption experiments, and DFT calculations, which reveals that anion exchange between Cl^- and SeO₄^2- is the main driving force for Se adsorption. Additionally, CTFS-Cl and CTFL-Cl perform well toward real contaminated river water sample with the residual Se being less than 8.49 μg/L. This work demonstrates the excellent performance of CTFs-based materials with great application prospect for Se removal in contaminated water treatment.

Exposure to melamine and its derivatives in Chinese adults: The cumulative risk assessment and the effect on routine blood parameters

Melamine (MEL) and its derivatives, ammeline (AMN), ammelide (AMD), cyanuric acid (CYA) are widely existed in environmental media. Animal studies have reported the cumulative risk assessment (CRA) of simultaneous exposure to MEL and its derivatives and explored the associations between exposure and routine blood parameters. Such information is largely unknown in human studies. In this study, we detected the urinary concentrations of MEL and its derivatives in 239 Chinese adults to conduct the CRA by evaluating their hazard quotients (HQ) and hazard Index (HI), and also explored the possible associations between exposure and measured routine blood parameters in study population. The detectable frequencies of MEL, AMN, AMD and CYA were 96.65%, 41.00%, 97.91% and 97.07%, respectively. The median values of creatinine (Cr)-adjusted MEL, AMN, AMD, CYA and the total concentrations of MEL and its derivatives (∑MEL) were 11.41 μg/g Cr, not detected (ND), 2.64 μg/g Cr, 15.30 μg/g Cr, 35.02 μg/g Cr, respectively. There were 9 (3.77%) participants with estimated daily intakes (EDIs) of CYA exceeding the tolerable daily intake (TDI) of 2500 ng/kg bw/day, and 12 (5.02%) participants with HI of ∑MEL exposure exceeding 1 based on the strictest TDI value. Urinary concentrations of MEL and its derivatives were positively associated with specific routine blood parameters, including hematocrit, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin concentration, mean corpuscular hemoglobin, white blood cell, neutrophil count (P < 0.05). Meanwhile, exposure to MEL and its derivatives increased the risk of red blood cell abnormality (P < 0.05). Our study is the first study to provide evidence-based data on the CRA of exposure to MEL and its derivatives in Chinese adults, and to propose a possible association between such exposure and routine blood parameters in human.

Surface facet Fe2O3-based visible light photocatalytic activation of persulfate for the removal of RR120 dye: nonlinear modeling and optimization

Photocatalytic activation of persulfate (PS) is recently emerged as an energy-efficient and environmentally sustainable approach for pollutants degradation, which enables to leverage the strengths of low-cost solar energy and heterogeneous catalysis. Herein, we investigated the photocatalytic decomposition of reactive red 120 (RR120) dye using PS-activated Fe₂O₃ nanoparticles and elucidated the effect of their facets, α-Fe₂O₃ (001), β-Fe₂O₃ (100), and γ-Fe₂O₃ (111). β-Fe₂O₃ not only boosted the charge carrier separation but also provided more active sites for PS activation resulting in 6- and 3.5-fold higher photocatalytic activities compared to α-Fe₂O₃ and γ-Fe₂O₃, respectively. Response surface methodology and artificial neural network coupled with genetic algorithm models were utilized to optimize and foresee Fe₂O₃/PS system under visible light. Almost 100% color removal and 82% organic removal were observed under the optimum conditions at 20 mg/L RR120, 22 mg/L β-Fe₂O₃, 18 mg/L PS, and pH: 3. Scavenger test indicated that both sulfate and hydroxyl radicals are responsible for the observed RR120 removal. Although cell viability test indicated that cytotoxicity of wastewater is not significantly reduced after treatment. All the results proposed that β-Fe₂O₃/PS at relatively low doses has a great potential to decompose and mineralize recalcitrant dyes in wastewater under invisible light.

A novel polymeric fluorescence sensor based on acrylated citric acid for detection of melamine adulteration: Application in milk powder

Melamine selective acrylate citric acid (ACA) based polymeric membrane sensor was prepared by radical polymerization method and the sensor was characterized. The sensor showed a selective fluorescent response to melamine (λ_ex/λ_em = 388/425 nm). The sensor response is linear in the concentration range of 3.96 × 10^-9 to 7.93 × 10^-8 mol L^-1, the optimum pH value is 6.0 and response time is less than 1 min. Limit of detection (LOD) and limit of quantification (LOQ) were calculated as 2.32 × 10^-10 mol L^-1 and as 7.74 × 10^-10 mol L^-1, respectively. The sensor showed great selectivity towards melamine in the presence of a large number of molecules and ions. The performance of sensor was also confirmed by determining of melamine in milk powder sample and the results were compared with HPLC results and acceptable results were obtained. As a conclusion, the results revealed that the proposed sensor is an interesting alternative for melamine determination.

A sketch of microbiological remediation of explosives-contaminated soil focused on state of art and the impact of technological advancement on hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) degradation

When high-energy explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 2,4,6-trinitrotoluene (TNT) are discharged into the surrounding soil and water during production, testing, open dumping, military, or civil activities, they leave a toxic footprint. The US Environmental Protection Agency has labeled RDX as a potential human carcinogen that must be degraded from contaminated sites quickly. Bioremediation of RDX is an exciting prospect that has received much attention in recent years. However, a lack of understanding of RDX biodegradation and the limitations of current approaches have hampered the widespread use of biodegradation-based strategies for RDX remediation at contamination sites. Consequently, new bioremediation technologies are required to enhance performance. In this review, we explore the requirements for in-silico analysis for producing biological models of microbial remediation of RDX in soil. On the other hand, potential gene editing methods for getting the host with target gene sequences responsible for the breakdown of RDX are also reported. Microbial formulations and biosensors for detection and bioremediation are also briefly described. The biodegradation of RDX offers an alternative remediation method that is both cost-effective and ecologically acceptable. It has the potential to be used in conjunction with other cutting-edge technologies to further increase the efficiency of RDX degradation.

High and stable surface-enhanced Raman spectroscopy activity of h-BN nanosheet/Au1Ag3 nanoalloy hybrid membrane for melamine determination

In this work, a hexagonal boron nitride (h-BN)/AuAg nanoalloy hybrids (NAHs) was synthesized to fabricate h-BN/Au1Ag3 membrane as a solid surface-enhanced Raman spectroscopy (SERS) substrate for sensitive SERS detection of melamine. The AuAg nanoalloys were in situ grown on h-BN by chemical reduction method, and the Au/Ag molar ratio was tuned to achieve optimal SERS performance. After the SERS performance of h-BN/AuAg NAHs with different Au/Ag ratios was analyzed, h-BN/Au1Ag3 NAHs were chosen for SERS analysis. The h-BN/Au1Ag3 membrane can be obtained through simple filtration of h-BN/Au1Ag3 NAHs on chromatographic paper. As expected, the solid SERS substrates of h-BN/Au1Ag3 membrane were uniform and demonstrated good selectivity, repeatability and reproducibility for SERS detection of melamine. The results demonstrate that h-BN/Au1Ag3 membrane exhibited high SERS activity for 4-mercaptobenzoic acid (4-MBA) with limit of detection (LOD) at 1.0 ng L-1, and its analytical enhancement factor (AEF) reached 3.6 × 108. The possible enhancement mechanism, including electromagnetic mechanisms (EM) and chemical mechanisms (CM) were illustrated by finite-difference time-domain (FDTD) and density functional theory (DFT) simulations in detail, respectively. The concentration of melamine in the 0.05-5.0 mg L-1 range showed good linear relationship (R2 = 0.9940) with SERS intensity with LOD of 0.01 mg L-1. Finally, the recoveries of melamine in liquid milk samples are 87.7-105.7% with relative standard deviations (RSDs) in range of 0.6-2.6%, providing precise safety evaluation of melamine in milk samples.

Migration of formaldehyde from 'biobased' bamboo/melamine cups: A Dutch retail survey

Bamboo/melamine cups had become popular, due to their ecofriendly and sustainable image. Some cups are marketed as biobased and biodegradable. These cups are made from melamine-formaldehyde resin to which bamboo fibers or powder are added. They may release formaldehyde and melamine into the beverage. In 2019 the Netherlands Food and Consumer Product Safety Authority conducted a market study. 46 cups were sampled in duplicate and tested for formaldehyde migration. 88% of the cups complied with the migration limit of 15 mg/kg. Some cups showed very high migration values, over 200 mg/kg. There is a high exposure of formaldehyde from other sources (food, environment). When applying a realistic worst-case scenario of a daily intake of 0.4 L of beverage from the cups, the health based guidance value is exceeded at a migration of 19 mg/kg and higher. For some of the cups that had a high migration of formaldehyde, health risks may occur. For food-utensils for babies and young children, the exposure is higher due to their lower body weight. The SML does not provide sufficient protection for babies and young children. Bamboo is not authorized in the EU as additive for plastic food contact materials. Therefore the Netherlands, Belgium, Luxembourg and other EU member states have actively banned these products from the market. Finally, bamboo/melamine tableware would suggest having a 'green' image and would contribute to the goals of the circular economy to use biobased raw materials, but by using it in combination with melamine-formaldehyde resin may affect food safety.

Does pH variation influence the toxicity of organic contaminants in estuarine sediments? Effects of Irgarol on nematode assemblages

Natural pH values in coastal waters vary largely among locations, ecosystems, and time periods; still, there is an ongoing acidification trend. In this scenario, more acidic pH values can alter bioavailability of organic contaminants, to organisms. Despite this, interactive effects between pH and chemical substances are not usually considered in Ecological Risk Assessment protocols. This study investigated the effects of pH on the toxicity of a hydrophobic organic compound on a benthic community using a microcosm experiment setup to assess the response of nematode assemblages exposed to environmentally relevant concentrations of Irgarol at two natural pH conditions. Estuarine nematode assemblages were exposed to two concentrations of Irgarol at pH 7.0 and 8.0 for periods of 7 and 35 days. Lower diversity of nematode genera was observed at the highest tested Irgarol concentration (1281 ± 65 ng.g^-1). The results showed that the effects of Irgarol contamination were independent of pH variation, indicating no influence of acidification within this range on the toxicity of Irgarol to benthic meiofauna. However, the results showed that estuarine nematode assemblages are impacted by long-term exposure to low (but naturally occurring) pHs. This indicates that estuarine organisms may be under naturally high physiological pressure and that permanent changes in the ecosystem's environmental factors, such as future coastal ocean acidification, may drive organisms closer to the edges of their tolerance windows.

Rapid analysis of triazine herbicides in fruit juices using evaporation-assisted dispersive liquid-liquid microextraction with solidification of floating organic droplets and HPLC-DAD

A rapid and convenient analytical procedure (evaporation-assisted dispersive liquid-liquid microextraction with solidification of floating organic droplets) is advanced for determining the concentrations of triazine herbicide residues (e.g. simazine and atrazine) in fruit juices via HPLC-DAD. The technique involves adding 1-dodecanol (low density) and dichloromethane (high density) to the test solution to act as the extraction and volatile solvents, respectively. Calcium oxide is added to generate heat to accelerate the evaporation of dichloromethane, whereupon the 1-dodecanol quickly disperses into small droplets to complete the microextraction process. Thus, there is no need to use a dispersive solvent and heating equipment is also not required. The floating 1-dodecanol is subsequently frozen using an ice bath to facilitate its separation from the sample. Under optimal conditions (250 μL of 1-dodecanol (extraction solvent), 150 μL of CH₂Cl₂ (volatile solvent), 1250 mg of CaO, and an extraction time of 60 s) the detection procedure is linear over the range 0.05-5 μg mL^-1 (with R > 0.99). The limits of detection (LOD) and quantification (LOQ) were determined to be 0.0022-0.0034 μg mL^-1 and 0.0073-0.0113 μg mL^-1, respectively. The recovery of simazine and atrazine in three fruit juices ranged between 78.5% and 96.4% with a relative standard deviation <8.2%. Therefore, the proposed approach can be effectively adopted to analyze the triazine herbicide content in fruit juices. The method has been proved to be simple, reliable, and remarkably efficient.

Natural dynamics and residues of pymetrozine for typical rice-growing areas of China

Pymetrozine has replaced toxic organophosphate pesticides previously used for controlling pests of rice crops in China. Existing data on its environmental behavior are usually related to studies on artificial plots that do not adequately address the natural dynamics and residues in actual field conditions. Therefore, studies under field conditions were carried out to investigate the natural dynamics and residues of pymetrozine in two typical rice-growing areas in China - Hunan and Guangxi provinces. Samples of paddy soil and water were collected in relation to spraying events in the study areas. The quick, easy, cheap, effective, rugged and safe (QuEChERS) method was used to extract pymetrozine residues from the samples by a Waters ACQUITY UPLC (Milford, MA, USA) system interfaced with a triple-quadrupole mass spectrometer (Xevo TQ-D, Waters Corp., USA). The initial deposition of pymetrozine in paddy soils was higher than in paddy waters in both areas. The decay of pymetrozine followed an exponential trend consistent with the first order kinetics. The half-life of pymetrozine in paddy water was determined to be 3.0 and 3.8 days, whereas the half-life in soil was 3.8 and 3.5 days in the Guangxi and Hunan samples, respectively. The decline rates of pymetrozine in paddy soil and paddy water in this field study were faster than those conducted under non-field conditions reported in previous studies. Compared to other pesticides used in China as reported in previous studies, the environmental persistence of pymetrozine in both paddy water and soils in Guangxi and Hunan provinces is very low. This has important implications for the use of pymetrozine in agricultural systems globally.

The first observation of antifouling organotin compounds and booster biocides in sediments from Samsun Port area, Black Sea, Turkey

The distribution of antifouling organotin compounds (OTCs) and booster biocides in surface sediments of Samsun Port (Black Sea, Turkey) in September 2014 was investigated by gas chromatography-tandem mass spectrometry (GC-MS/MS) method. The total organotin concentrations ranged from <1.0 to 669.6 ng/g, dw. Among the studied booster biocides, Diuron (<1.0-11.28 ng/g) was found in 70.58% of the investigated sediments, while Irgarol (<1.0-26.53 ng/g) was detected in two stations. Traces of fresh input organotin and high Irgarol were found at the park/repairment points of the port. The Principal Component Analysis (PCA) showed that sediment characteristic types and Total Organic Carbon (TOC) were the main relevant parameters in the accumulation of antifouling contamination in the Port area. In comparison with several types of environmental sediment quality criteria, Samsun Port is highly polluted area. The concentrations of OTCs and Diuron maybe used as a baseline reference level for future monitoring programs in Turkish Ports.

Application of a Screen-Printed Sensor Modified with Carbon Nanofibers for the Voltammetric Analysis of an Anticancer Disubstituted Fused Triazinone

In this paper, we propose the first analytical procedure—using a screen-printed carbon electrode modified with carbon nanofibers (SPCE/CNFs)—for the detection and quantitative determination of an electroactive disubstituted fused triazinone, namely 4-Cl-PIMT, which is a promising anticancer drug candidate. The electrochemical performances of the sensor were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square-wave adsorptive stripping voltammetry (SWAdSV). The presence of carbon nanofibers on the sensor surface caused a decrease in charge-transfer resistance and an increase in the active surface compared to the bare SPCE. Under the optimised experimental conditions, the proposed voltammetric procedure possesses a good linear response for the determination of 4-Cl-PIMT in the two linear ranges of 0.5–10 nM and 10–100 nM. The low limits of detection and quantification were calculated at 0.099 and 0.33 nM, respectively. In addition, the sensor displays high reproducibility and repeatability, as well as good selectivity. The selectivity was improved through the use of a flow system and a short accumulation time. The SWAdSV procedure with SPCE/CNFs was applied to determine 4-Cl-PIMT in human serum samples. The SWAdSV results were compared to those obtained by the ultra-high-performance liquid chromatography coupled with electrospray ionization/single-quadrupole mass spectrometry (UHPLC-ESI-MS) method.

Contamination characteristics of energetic compounds in soils of two different types of military demolition range in China

The pollution of energetic compounds (ECs) in military ranges has become the focus of worldwide attention. However, few studies on the contamination of ECs at Chinese military ranges have been reported to date. In this study, two different types of military demolition range in China, Dunhua (DH) and Taiyuan (TY), were investigated and the ECs in their soils were determined. 10 ECs were detected at both ranges. While all the contamination characteristics were distinct, 2,4,6-trinitrotoluene (TNT) was the most abundant contamination source in soils at DH range, with an average concentration of 1106 mg kg^-1 and a maximum concentration of 34,083 mg kg^-1. Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and two mono-amino degradation products of TNT were also found to have high concentrations, with potential ecological and human health risks. In contrast, the concentrations of ECs in soils of TY range were much lower. The content of RDX was most significant, with average and maximum concentrations of 7.8 and 158 mg kg^-1, respectively. However, the potential threat to human health of 2,4-dinitrotoluene and 2,6-dinitrotoluene in soils at both ranges should not be ignored. The differences in pollution characteristics of the ECs at DH and TY are closely related to the types and amounts of the munitions destroyed. Moreover, the spatial distribution of ECs at the demolition ranges was extremely heterogeneous, which may be attributed to the use of open burning / open detonation and the non-homogeneous composition of the munitions.

Environmental Characterization of Underwater Munitions Constituents at a Former Military Training Range

As a result of military activities, unexploded ordnance and discarded military munitions are present in underwater environments, which has resulted in the release of munitions constituents including the high explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), along with their primary degradation products, to the water column and adjacent sediments. The present study focused on the characterization of underwater exposure and concentrations of energetics such as TNT and RDX at the former Vieques Naval Training Range at Bahia Salina del Sur (Vieques, Puerto Rico, USA), a bay with documented high incidence of munitions. In situ passive sampling using polar organic chemical integrative samplers (POCIS) was used for the detection and quantification of constituents in water at target locations approximately 15 to 30 cm from 15 individual potentially leaking munitions, and also at 15 unbiased locations approximately evenly spaced across the Bay. For comparison with POCIS-derived concentrations, grab samples were taken at the POCIS target locations. The POCIS-derived and averaged grab samples agreed within a factor of 3. When detected, munitions constituent concentrations (primarily TNT and RDX) were observed at ultratrace concentrations (as low as 4 ng/L for RDX), except 30 cm from one General Purpose bomb where the TNT concentration was 5.3 µg/L, indicating that low-level contamination exists at Bahia Salina del Sur on a very localized scale despite the relatively high density of munitions, similar to previously reported results for other munitions sites around the world. Sediment and porewater sampled at 4 stations where munitions constituents were detected in the water column had concentrations below detection (approximately 5 µg/kg and 5 ng/L, respectively), suggesting that the sediment was not a sink for these constituents at those locations. Environ Toxicol Chem 2022;41:275-286. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Vortex-assisted dispersive liquid-liquid microextraction based on the solidification of sedimentary deep eutectic solvents for the determination of triazine and phenylurea herbicides in milk samples

Vortex-assisted dispersive liquid-liquid microextraction based on the solidification of sedimentary deep eutectic solvents was developed and applied to the extraction of triazine and phenylurea herbicides in milk samples. In this study, a series of novel hydrophobic deep eutectic solvents were prepared using tetrabutylammonium chloride as the hydrogen bond acceptor and perfluorooctanol as the hydrogen bond donor, and their structures, viscosities, densities and melting points were determined. The deep eutectic solvent was used as the extraction solvent and dispersed in the sample solution with the assistance of vortex. After extraction, through centrifugation and subsequent cooling in an ice bath, the deep eutectic solvent was solidified and deposited on the bottom of the centrifuge tube. Subsequently, the deep eutectic solvent combined with the target analytes was diluted and used for chromatographic analysis. Some parameters, including the extraction temperature, type and volume of the deep eutectic solvent, amount of NaCl, vortex time and pH of the sample solution, were optimized by the single-factor experiment, Plackett-Burman design and Box-Behnken design. The limits of detection and quantification were in the range of 0.41-0.59 μg L^-1 and 1.37-1.95 μg L^-1, respectively. The intra-day precision and inter-day precision were in the range of 0.28-2.14% and 2.02-7.99%, respectively. The present method was successfully applied to the determination of triazine and phenylurea herbicides in milk samples.

Biotransformation of 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) can contribute to high levels of 2,4,6-tribromophenol (2,4,6-TBP) in humans

2,4,6-Tribromophenol (2,4,6-TBP) is a brominated flame retardant that accumulates in human tissues and is a potential toxicant. Previous studies found 2,4,6-TBP levels in human tissues were significantly higher than those of brominated flame retardants measured in the same samples. In contrast, the levels of 2,4,6-TBP in the environment and foodstuff are not elevated, suggesting a low potential for direct intake through environmental exposure or diet. Here, we hypothesized that high levels of 2,4,6-TBP in human tissues are partially from the indirect exposure sources, such as biotransformation of highly brominated substances. We conducted in vitro assays utilizing human and rat liver microsomes to compare the biotransformation rates of four highly brominated flame retardants, which could potentially transform to 2,4,6-TBP, including decabromodiphenyl ethane (DBDPE), 2,4,6-tris-(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and tetrabromobisphenol A (TBBPA). Our results show that TTBP-TAZ rapidly metabolizes in both human and rat liver microsomes with a half-life of 1.1 and 2.2 h, respectively, suggesting that TTBP-TAZ is a potential precursor of 2,4,6-TBP. In contrast, 2,4,6-TBP was not formed as a result of biotransformation of TBBPA, BTBPE, and DBDPE in both human and rat liver microsomes. We applied suspect and target screening to explore the metabolic pathways of TTBP-TAZ and identified 2,4,6-TBP as a major metabolite of TTBP-TAZ accounting for 87% of all formed metabolites. These in vitro results were further tested by an in vivo experiment in which 2,4,6-TBP was detected in the rat blood and liver at concentrations of 270 ± 110 and 50 ± 14 μg/g lipid weight, respectively, after being exposed to 250 mg/kg body weight/day of TTBP-TAZ for a week. The hepatic mRNA expression demonstrated that TTBP-TAZ significantly activates the aryl hydrocarbon receptor (AhR) and promotes fatty degeneration (18 and 28-fold change compared to control, respectively) in rats.

Analysis of pesticide residues by a support vector machine combined with fluorescence spectroscopy

Pesticide residues enter a lake through the water cycle, causing harm to the water environment and human health. It is necessary to select highly sensitive fluorescence spectroscopy to detect pesticides (bifenthrin, prochloraz, and cyromazine), and a support vector machine (SVM) is used to analyze the concentration of pesticides. In addition, this paper adopts K-fold cross validation and a grid search to optimize the SVM algorithm. The performance evaluation index and running time prove the reliability of the results of this experiment. They show that fluorescence spectroscopy combined with SVM is efficient in predicting pesticide residue content.

A Lanthanide Complex Fluorescent Probe for the Detection of Melamine

Melamine has been illegally adulterated in dairy food because of the rich nitrogen content and stable chemical properties in recent years. Therefore, the detection of melamine is of great significance for food safety supervision and human health protection. As melamine is a weak fluorescent substance, it is difficult to detect melamine directly by fluorescence spectroscopy. In this work, we found that melamine can significantly enhance the emission of the tetracycline-europium (EuTC) complex at 616 nm. Therefore, we took EuTC complex as a fluorescent probe to detect melamine. According to the characterizations of absorption spectra, molecular electrostatic potential distribution, and the time-resolved spectra, we speculated that tetracycline and melamine may form a complex through hydrogen bonding interaction in the melamine-EuTC reaction system, causing the melamine closer approach to Eu³⁺ and reducing the non-radiative energy loss of water molecules to Eu³⁺, which significantly enhanced the fluorescence intensity of EuTC. The fluorescence intensity of EuTC complex with melamine concentration in the range of 0.5-40.0 μM shows a good linear relationship, and the correlation coefficient is 0.9951 with the detection limit of 7.85 × 10^-8M. It shows a high sensitivity for the EuTC complex as a fluorescent probe to detect melamine, which provides a supplement and extension for the detection of melamine by fluorescence spectroscopy.

In-vessel composting of HMX and RDX contaminated sludge using microbes isolated from contaminated site

Current study was carried out with an objective to remediate highly contaminated sludge with HMX and RDX obtained from an explosive manufacturing facility in North India employing indigenous microbes, Arthrobacter subterraneus (isolate no. S2-TSB-17) and Bacillus sonorensis (isolate no. S8-TSB-4) which were isolated from the same contaminated site. In-vessel composting of the explosive contaminated sludge was performed in 12 different bioreactors using cow manure and garden waste as bulking agents. 78.5% degradation of HMX was observed in reactor no. 2 with Bacillus sonorensis having combination of 10% sludge, 70% cow manure and 20% garden waste on 80th day. Two secondary metabolites Bis(hydroxymethyl)nitramine and methylene dinitramine were identified while studying the degradation pathway. Similarly, degradation of 91.2% was observed for RDX in reactor no. 11 with consortia of Arthrobacter subterraneus and Bacillus sonorensis on 80th day. During the study, release of significant nitrate and nitrite ions were observed. It has already been established that RDX and HMX degradation leads to release of nitrite/nitrate ions. The highest nitrite (reactor no. 11) and nitrate (reactor no. 2) release observed were 24.02 ± 0.05 mg/kg and 30.65 ± 0.99 mg/kg on 50th and 70th day, respectively. Scanning electron microscopic studies confirmed the attachment and presence of microbes with solid surface and no deformation in structure was observed in the microbial cells due to contamination stress. Findings of the study concluded that in-vessel composting assisted with native bacterial species can be a potential technology for the treatment of explosive contaminated sludge at the contaminated sites.

Microbial community structure and metabolome profiling characteristics of soil contaminated by TNT, RDX, and HMX

This experiment was conducted to evaluate the ecotoxicity of typical explosives and their mechanisms in the soil microenvironment. Here, TNT (trinitrotoluene), RDX (cyclotrimethylene trinitramine), and HMX (cyclotetramethylene tetranitramine) were used to simulate the soil pollution of single explosives and their combination. The changes in soil enzyme activity and microbial community structure and function were analyzed in soil, and the effects of explosives exposure on the soil metabolic spectrum were revealed by non-targeted metabonomics. TNT, RDX, and HMX exposure significantly inhibited soil microbial respiration and urease and dehydrogenase activities. Explosives treatment reduced the diversity and richness of the soil microbial community structure, and the microorganisms able to degrade explosives began to occupy the soil niche, with the Sphingomonadaceae, Actinobacteria, and Gammaproteobacteria showing significantly increased relative abundances. Non-targeted metabonomics analysis showed that the main soil differential metabolites under explosives stress were lipids and lipid-like molecules, organic acids and derivatives, with the phosphotransferase system (PTS) pathway the most enriched pathway. The metabolic pathways for carbohydrates, lipids, and amino acids in soil were specifically inhibited. Therefore, residues of TNT, RDX, and HMX in the soil could inhibit soil metabolic processes and change the structure of the soil microbial community.

The inhibitory effects of the antifouling compound Irgarol 1051 on the marine diatom Skeletonema sp. across a broad range of photosynthetically active radiation

The release of anthropogenic organic pollutants has resulted in extensive environmental risks to coastal waters. Among pollutants released, the most common antifoulant, Irgarol 1051, is an effective inhibitor of photosystem II of photoautotrophs; thus, the continuous release of this compound into surrounding seawater would potentially threaten marine algae. To investigate this, we grew the model marine diatom Skeletonema sp. at different concentrations of Irgarol 1051 and levels of photosynthetically active radiation (PAR). Irgarol did not affect the photochemical capacity when cells were incubated in the dark, but photochemical yields all significantly decreased, and relative inhibition by Irgarol increased once cells were exposed to even the lowest PAR, with lower photochemical yields observed under increased level of Irgarol. In addition, the rate of decrease in yield increased with Irgarol concentration but was unchanged among PAR treatments. The growth rates showed a similar pattern to photochemical yields, with lower values under higher Irgarol concentrations, but with no significant differences in the effect of Irgarol observed between the light levels employed. The ratio of repair to damage rates of PSII clearly shows that this ratio decreased with light intensity, largely due to increases in damage rates and that the PAR level at which repair balanced damage decreased under a high level of Irgarol. Our results suggest that the inhibitory effects of Irgarol become obvious after PAR exposure even at a relatively low light level, suggesting that Irgarol would affect phytoplankton throughout the daytime, and may therefore have a broad environmental risk, potentially limiting coastal primary production.

A low-cost and effective bagasse-based magnetic porous biochar as an adsorbent for solid phase extraction of triazine herbicides in brown sugar

A rapid and sensitive approach for enriching and extracting triazines from brown sugar samples was developed by combining magnetic dispersive solid-phase extraction and HPLC/UV. In this work, a magnetic porous biochar (MPB) derived from low-cost bagasse was prepared and successfully employed as an adsorbent. A particular emphasis was placed on optimizing the extraction conditions, including the amount of MPB, extraction time, pH, type and volume of eluent, and salt concentration. Under optimized MSPE conditions, the method showed satisfactory linearity over concentration ranges of 2-200 μg L^-1 for four triazines, with correlation coefficient values no less than 0.9981. Low limits of detection (0.27-0.33 μg L^-1), good recoveries (81.7-100.7%), and satisfactory repeatability (RSDs ≤ 8.1%) were also demonstrated with respect to the analytical performance. The results demonstrated that the developed method was simple, rapid, sensitive, and efficient, indicating that it could extract and enrich trace triazines from real samples.

Residue behavior and safety evaluation of pymetrozine in tea

BACKGROUND

Pymetrozine is a widely used pesticide. It is challenging to analyze and difficult to manage due to the large gap in its global maximum residue limits (MRLs) in tea. The development of a high-efficiency detection method for the evaluation of the transfer of residual pymetrozine from tea plantations to tea cups is therefore of prime significance.

RESULTS

An analytical method for the determination of pymetrozine residues in tea was established based on Cleanert PCX solid-phase extraction. The average recoveries were 72.2-93.7%, with relative standard deviations (RSDs) of less than 12%. The limits of quantification (LOQs) were 0.005 mg·kg^-1 in fresh tea leaves and dry tea, and 0.00025 mg·L^-1 in tea brew. Pymetrozine degraded rapidly in tea plants with a half-life (t_1/2 ) of 1.9 days in open tea plantations, and decreased by 9.4-23.7% in the green tea-processing procedure, which was concentration dependent. The residual pymetrozine levels in green tea collected at 6 and 21 days were below the MRLs in China and EU at a dosage of 30 g a.i. ha^-1 , respectively. The leaching rates of pymetrozine from dry tea to tea brew were 58.7-96.3%. Hazard quotient (HQ) values of pymetrozine were significantly <100% when tea shoots were plucked in 6 days, which indicated a negligible risk to humans.

CONCLUSION

This work allows the determination of residual pymetrozine in tea and illustrates a low intake risk with the use of pymetrozine in tea plantations. It could serve as reference for further regulation consideration for maximum residue limits (MRLs). © 2020 Society of Chemical Industry.

Ecological risk assessment of booster biocides in sediments of the Brazilian coastal areas

Although booster biocides (Irgarol, diuron, chlorothalonil, dichlofluanid, and DCOIT) have been detected in sediments along the Brazilian coastal areas, the risk associated to their occurrence and levels is still unknown. Thus, the ecological risk of booster biocides to sediment-dwelling organisms from the Brazilian coast was assessed using a risk characterization approach through the Risk Quotient (Measured environmental concentration (MEC)/Predicted no effect concentrations (PNECs)). Sedimentary PNECs for Irgarol, diuron, chlorothalonil and DCOIT were derived based on published ecotoxicological data from both freshwater and marine studies, while a NORMAN methodology was used to derived it for dichlofluanid. Results showed that DCOIT, diuron, Irgarol, chlorothalonil, and dichlofluanid can pose high risk on 47%, 35%, 15%, 1% and 1%, respectively, of the 113 Brazilian sites appraised. Considering the trend of expansion of navigation/maritime activities, DCOIT may worsen its impact over the coastal areas of Brazil, especially ports, but also ship/boatyards, marinas, and maritime traffic zones. The present study is an important contribution to support advance on policy formulation concerning booster biocides worldwide, particularly considering the lack of regulation on the use of antifouling biocides in Brazil.

Constructing slow-release formulations of herbicide metribuzin using its co-extrusion with biodegradable polyester poly-ε-caprolactone

Different technologies to prepare long term pesticide forms include polymer coating, preparing composites and encapsulating pesticides in nanoparticles. A simple and low-cost method was proposed to obtain slow-release formulations by co-extrusion of a pesticide with a biodegradable polymer at a temperature above the melting points of both components. A herbicide metribuzin and low-melting polyester poly-ε-caprolactone were chosen for this work. Formulations containing 10%, 20%, and 40% herbicide were prepared. During 7 days of their exposition in water, it was released from 81% to 96% of initially loaded metribuzin; the highest release was detected for 40%-loaded forms. Biodegradation of the constructs and pesticide release were further studied in the model soil. Degradation rates of the specimens increased with an increase in pesticide content, from 9% to 20% over 14 weeks for the 10%/20%-loaded and the 40%-loaded specimens, respectively. The release of metribuzin reached, respectively, 37-38% and 55%. The herbicide content in soil was lower due to its partial degradation in soil; it reached 23-25% and 33%, respectively, from initially loaded into the polymer matrix. Release kinetics of metribuzin in water as in soil best fitted the First-order model. The used approach is promising for obtaining long-term release formulations for soil applications.

A novel egg shell-based bio formulation for remediation of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) contaminated soil

Environmental contamination by secondary explosive has been posing threat to human health and the ecosystem. We investigated the potential of a novel bioformulation developed from poultry waste for the bioremediation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated soils. Eggshells and additives immobilized with an indigenous explosive degrading microbe Janibacter cremeus were utilized for the development of the wettable powder bioformulation. Treatments carried out under unsaturated and saturated soil conditions resulted in 62 and 73 % removal of RDX respectively in 35 days meeting the soil clean up goals. The saturated treatment sets exhibited better microbial growth during the study in terms of live cell count and total enzyme activity. The bacteria, J. cremeus was observed to exhibit significant release of nitrite under both unsaturated as well as saturated conditions. Mass spectrometric studies showed that, both the conditions lead to the formation of nitroso-derivatives of RDX. But under saturated condition, an intermediate, 5-hydroxy-4-nitro-2,4-diazapentanal was observed which is a precursor to 4-nitro-2,4-diazabuatnal ultimately leading to mineralization. An accessible bio resource from poultry waste when used as a carrier for explosive degrading microbe has proven effective for in situ remediation of explosive contaminated soils.

Determination of the N-Nitroso Compounds in Mouse Following RDX Exposure

Hexahydro-1,3,5-trinitro-1,3,5-triazine, commonly called RDX, is an important explosive, which is widely used in military and civic activities. As it is used, RDX is widely found in many locations and caused soil and water contamination. Many studies show that RDX is toxic to many organisms, including plants, animals, and microbes. RDX causes genetic toxicity and neurotoxicity as well as potential carcinogenesis. Even it is worse that RDX can be biotransformed into other N-nitroso derivatives, such as MNX, DNX, and TNX; these derivatives can be found in both naturally in RDX-contaminated soil and also in the animal GI tracks. To study the potential effect of RDX and its N-nitroso derivatives, this chapter presents a step-by-step method for detect RDX and its N-nitroso derivatives in animal stomach and GI tracts followed RDX exposure by gas chromatography with electron capture detector (GC/ECD). This method can also be used to detect RDX and its N-nitroso derivatives in other tissues and in other animals and plants.