Melamine

Food Chem. 2025 Aug 13;493(Pt 4):145933. doi: 10.1016/j.foodchem.2025.145933. Online ahead of print.

ABSTRACT

Malachite green (MG) is a toxic contaminant commonly found in aquaculture, making its effective removal and detection crucially important. In this study, MIL-100(Fe) was synthesized via a microwave-assisted hydrothermal method under optimized conditions (150 °C, 200 W, 30 min; FeCl₃·6H₂O:H₃BTC = 2:3). The resulting material exhibited excellent structural stability, a high specific surface area (1169.9 m²/g), and a remarkable MG adsorption capacity of 714.29 mg/g. To enable practical application and reusability, MIL-100(Fe) was immobilized onto a melamine sponge (MeS) using polyvinylidene fluoride (PVDF) as binding agent, forming a recyclable MeS/PVDF/MOF composite. When applied for solid-phase extraction of MG in conjunction with UV detection, the composite demonstrated high recovery rates (92.1-99.4 %), a low detection limit (2.29 μg/L), and consistent performance with over 80 % recovery after six reuse cycles in both real fish and wastewater samples. This study presents a simple, efficient and sustainable strategy for the adsorption and detection of MG in aquatic food matrices.

PMID:40848346 | DOI:10.1016/j.foodchem.2025.145933

Data Brief. 2025 Aug 6;62:111965. doi: 10.1016/j.dib.2025.111965. eCollection 2025 Oct.

ABSTRACT

Wood based panels are widely used in construction and furniture due to their cost effectiveness, sustainability, and processability. However, adhesives and additives used in these engineered materials may release volatile organic compounds (VOCs), including formaldehyde and BTEX compounds, affecting indoor air quality. This study presents a dataset examining VOC emissions from three commonly used panels: pine wood board (PWB), low pressure melamine particleboard (LPM), and particleboard (PB), and their potential health impacts in mice. To reflect a real-life early-phase exposure scenario, the panels were not pre-conditioned and were installed on three sides of a 50 × 50 × 50 cm acrylic chamber with passive air exchange only. Air samples were collected nine times over 14 days using automatic thermal desorption gas chromatography/mass spectrometry (ATD GC MS). VOCs were categorized as total VOCs (TVOC), natural VOCs (NVOC), five hazardous VOCs (BTEX plus styrene; 5VOC), and formaldehyde. Male BALB/c mice (n = 4 per group) were continuously exposed to each chamber for 14 days. Body weight was monitored on days 7 and 14, and 21 hematological and serum biochemical parameters were analyzed after exposure. Organs including the liver, kidney, lung, heart, and spleen were weighed and histologically examined. The dataset includes time resolved emission profiles for each panel type, longitudinal body weight measurements, blood and serum biochemical markers, and histological images. VOC emissions varied by material, with detectable formaldehyde in LPM and PB, and predominantly NVOC in PWB. No abnormal behaviors were observed during exposure. Statistically significant differences were noted in some blood parameters and organ weights between control and exposed groups, although all values remained within the normal physiological range. Histopathological analysis likewise revealed no specific abnormalities. This dataset supports future studies on VOC exposure response modeling, regulatory benchmarking, or risk mitigation strategies and contributes to understanding acute biological responses to real world wood panel emissions.

PMID:40837475 | PMC:PMC12361599 | DOI:10.1016/j.dib.2025.111965

Water Res. 2025 Aug 7;287(Pt A):124366. doi: 10.1016/j.watres.2025.124366. Online ahead of print.

ABSTRACT

Tire additives and their transformation products (TATPs) are increasingly recognized for their toxicity and widespread environmental presence. However, the interplay of rainfall, seasonal variation, and stream type in governing their multi-media partitioning and risks remains largely unexplored. This study investigated the spatiotemporal distribution, environmental drivers, and ecological risks of 21 TATPs in three distinct urban streams (general road, expressway, and rural road-adjacent). Seventeen, 19, and 14 TATPs were quantified in water (514-6541 ng/L), suspended particulate matter (SPM, 12.8-244 ng/L), and sediment (1.71-248 ng/g), respectively. Rainfall significantly altered aqueous TATP levels, while stream type and seasonal variation influenced TATP pollution in SPM and sediment. Multiple linear regression identified pH, temperature, and road area as key aqueous-phase drivers, whereas precipitation and road area controlled the levels of TATPs in SPM and sediment, respectively. Hydrophobicity was a key determinant in TATP multi-media partitioning. High ecological risks were found across all water samples, primarily associated with 1,3-diphenylurea (DPU), 1,3-dicyclohexylurea (DCU), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q), and hexa(methoxymethyl)melamine (HMMM). Eight TATPs exhibited persistence, bioaccumulation, or toxicity traits, warranting prioritized regulation. These insights are crucial for crafting effective environmental policies to mitigate =TATP impacts and protect urban aquatic ecosystems.

PMID:40819446 | DOI:10.1016/j.watres.2025.124366

J Chromatogr A. 2025 Aug 9;1760:466280. doi: 10.1016/j.chroma.2025.466280. Online ahead of print.

ABSTRACT

Melamine-formaldehyde resins are used in various industrial applications. As melamine is a toxic compound on the candidate list of Substances of Very High Concern, its content in melamine-based resins is important. Here we present two high-performance liquid chromatography methods suitable for the determination of free melamine content in uncured non-ionic and negatively charged melamine-based resins. A gradient reversed-phase liquid chromatography method using a C18 column was developed for the determination of free melamine content in non-ionic resins, while an isocratic mixed-mode liquid chromatography method using a Primesep 100 column was developed for the quantification of free melamine in sulfonated melamine-based resins. Both methods utilise ultraviolet detection, which allows the quantification of melamine in melamine-based resins with a limit of quantification of ∼10^-3% by weight and good repeatability and linearity over a wide range of melamine concentrations.

PMID:40818432 | DOI:10.1016/j.chroma.2025.466280

Aquat Toxicol. 2025 Aug 10;287:107537. doi: 10.1016/j.aquatox.2025.107537. Online ahead of print.

ABSTRACT

Concerns over plastic-associated chemical toxicity are increasing amid the plastic pollution crisis. Halogenated flame retardants, though effective in plastic development, are being phased out due to toxicity, while nitrogen-based alternatives, such as melamine cyanurate (MC), are considered more chemically stable and less toxic. Here, we assess the solubility and chemical stability of MC in freshwater using various solvents and evaluate degradation after UV exposure. Additionally, we compare the acute and chronic aquatic toxicity of MC to the more widespread halogenated flame retardant tetrabromophthalic anhydride (TBA) using the Daphnia magna invertebrate model. Toxicity of a common solvent, dimethyl sulfoxide (DMSO), was also assessed. MC was insoluble in 16 of 18 tested solvents, with solubility only seen in a strong acid and base. UV exposure for 72 h within freshwater media indicated minimal degradation, classifying MC as a highly stable compound. Acute toxicity tests at 1-20 mg/L showed no significant difference in EC₅₀ values between TBA (0.16 - 11.46 mg/L) and MC (5.91 - 13.23 mg/L). Chronic toxicity tests at 0.5, 5, and 15 mg/L yielded NOEC values of ≤5 mg/L for TBA and <5 mg/L for MC. At 15 mg/L, chronic exposure to TBA, MC, and DMSO resulted in 100% mortality in D. magna. These findings challenge the assumption that DMSO is a low-toxicity solvent in aquatic testing. Overall, the study highlights the difficulty in assessing the toxicity of highly stable flame retardants like MC, while indicating that they may exhibit similar aquatic toxicity as halogenated congeners.

PMID:40816006 | DOI:10.1016/j.aquatox.2025.107537

Appl Opt. 2025 Jul 10;64(20):5852-5859. doi: 10.1364/AO.561321.

ABSTRACT

Milk adulteration through dilution and the addition of nitrogen-rich chemicals is a persistent issue in the dairy industry, affecting product quality and consumer safety. Current monitoring techniques often rely on protein nitrogen content, which can be misrepresented by these additives. We report a reflective holographic sensor that can directly detect diluted milk by monitoring the shrinkage of the holographic grating, which induces a rapid and reversible blue shift of 34 nm across milk dilutions ranging from 10 to 100 vol%. The holographic milk sensor demonstrates high selectivity, remaining unaffected by variations in fat content, ionic strength, or pH. Testing with various casein suspensions reveals that the shrinkage effect is specifically triggered by calcium caseinate micelles, in marked contrast to free casein slurries in water. Moreover, adding melamine to artificially compensate for the nitrogen loss in diluted milk results in swelling rather than contraction. This holographic sensor offers a reliable and effective tool for quality control in the dairy industry.

PMID:40793746 | DOI:10.1364/AO.561321

Spectrochim Acta A Mol Biomol Spectrosc. 2026 Jan 5;344(Pt 2):126751. doi: 10.1016/j.saa.2025.126751. Epub 2025 Jul 29.

ABSTRACT

Melamine contamination from illegal additives, packaging contaminants, and pesticide residues threatens dairy product safety, demanding rapid detection. Traditional methods such as chromatography or mass spectrometry are precise but lack field applicability due to complexity, time consumption, and cost. Surface-enhanced Raman spectroscopy (SERS) is a promising alternative for sensitive, rapid, and label-free analysis. However, current SERS implementations face challenges like complex substrate synthesis, environmentally harmful sample processing, and lack of discrimination of analogues. Thus, developing a simple SERS-based method for detecting melamine and its analogues without pretreatment remains urgent. In this paper, a straightforward SERS detection method is proposed to achieve accurate and rapid pretreatment-free detection of melamine in milk. Polytetrafluoroethylene‑silver nanospheres (PTFE-AgNPs) SERS substrate is fabricated by mixing silver colloid, sodium hydroxide and sodium chloride solution, followed by deposition onto a PTFE filter membrane by filter-pressing assembly. Additionally, diluted milk is subjected to SERS testing directly without any pretreatment. Furthermore, both qualitative and quantitative analyses were performed using RF, PCA-SVM and CNN. Among the three algorithms, CNN classification model achieved the best accuracy 99.25 % for distinguishing melamine, ammeline, ammelide, and blank controls, while the CNN regression model yielded a coefficient of determination (R²) of 0.9999 for melamine quantification. The limit of detection (LOD) for melamine in milk was 3.32 × 10^-6 M, lower than the World Health Organization (WHO) recommended limit. This method, featuring simple SERS substrate preparation and non-pretreatment, enables rapid and efficient detection of melamine and its analogues, promoting broader applications of SERS in food safety monitoring.

PMID:40749506 | DOI:10.1016/j.saa.2025.126751

Langmuir. 2025 Aug 12;41(31):21144-21160. doi: 10.1021/acs.langmuir.5c03079. Epub 2025 Jul 29.

ABSTRACT

Carbon nitride (g-C₃N₄, CN) is always used as a metal-free catalyst to activate peroxymonosulfate (PMS) without toxic metal ion leaching in solutions. However, it is still a challenge to enhance the catalytic activity for CN. Herein, sulfur (S)-doped g-C₃N₄ is synthesized by a facile method as named CNS_x, where x represents the mass ratio of ammonium sulfate to melamine during the CNS_x synthesis. Partial N atoms such as pyridinic N in CN were replaced by S atoms. CNS_1.75 exhibited an excellent catalytic activity to degrade Rhodamine B (RhB) via PMS activation under the assistance of the visible light (Vis). The rate constant (k) increased about 9 and 7 times for CNS_1.75/Vis/PMS than that of CNS_1.75/PMS and CNS/Vis/PMS systems. Moreover, the k value is higher than that of some metal-doped CN as reported. The toxicity of RhB was effectively reduced after the degradation process with the total organic carbon (TOC) removal ratio 48% after 40 min. The RhB removal efficiency kept 95% after continuous operation for 12 h. The catalytic mechanism was proposed in which ¹O₂ was the dominant reactive oxygen species (ROS).

PMID:40726166 | DOI:10.1021/acs.langmuir.5c03079

Environ Sci Technol. 2025 Aug 12;59(31):16282-16292. doi: 10.1021/acs.est.5c03579. Epub 2025 Jul 28.

ABSTRACT

Melamine (MEL) and its derivatives are known for acute nephrotoxicity, but the risks from chronic exposure and underlying mechanisms of toxicity are unclear. We integrated environmental monitoring (356 pairs of house dust and urine samples collected across mainland China) with cell-based bioassays to investigate MEL exposure sources and toxic effects. MEL-related chemicals were frequently detected in dust (median: 10.3 μg/g) and urine (22.3 ng/mL) samples, indicating their widespread presence in indoor environments and chronic exposure among the Chinese population. Significant positive correlations were observed between MEL-related chemicals and neutrophil gelatinase-associated lipocalin (NGAL), a urinary biomarker of nephrotoxicity. RNA-sequencing of MEL-exposed human kidney-2 (HK-2) cells revealed significant enrichment of the ferroptosis signaling pathway. Further bioassays demonstrated that MEL exposure induces iron-driven mitochondrial lipid peroxidation in HK-2 cells. The system X_c^-/GPX4, ACSL4, and TFR1/DMT1 pathways identified as potential targets in ferroptosis-mediated early renal injury in both acute toxicity experiments and chronic exposure to environmentally relevant concentrations. This finding was further supported by urinary malondialdehyde and Fe²⁺ levels that mediated 13-31% of the effect of MEL-related chemicals on NGAL in humans. Our study provides valuable insights into the role of ferroptosis in chronic kidney injury associated with environmental exposure to MEL and its derivatives.

PMID:40719558 | DOI:10.1021/acs.est.5c03579

Mikrochim Acta. 2025 Jul 28;192(8):531. doi: 10.1007/s00604-025-07422-4.

ABSTRACT

A novel ratiometric fluorescent probe was developed by combining terbium-doped boron/nitrogen co-doped carbon dots (Tb@BNCDs) with thiolated-protected gold nanoclusters (Th@Au NCs) for efficient melamine detection based on a competitive coordination mechanism. The designed system exploits the synergistic effects of aggregation-induced emission (AIE) and Förster resonance energy transfer (FRET) processes. The Tb@BNCDs, formed via coordination of Tb³⁺ ions with the amino and carboxyl groups on BNCDs, serve as both a stable fluorescence source and a coordination site for melamine interaction. Simultaneously, the weakly emissive Th@Au NCs were activated through Tb³⁺-induced aggregation, yielding a hybrid nanostructure exhibiting dual emission peaks at 470 nm and 630 nm. Upon the introduction of melamine, competitive binding to Tb³⁺ ions occurs via melamine's nitrogen-rich triazine structure, disrupting the original coordination complexes. This displacement interferes with AIE and FRET pathways, resulting in quantifiable changes in fluorescence emission intensity ratios (F₄₇₀/F₆₃₀), and enabling ratiometric detection. The probe demonstrates a broad linear detection range (0.01-300 µM), an ultra-low limit of detection (LOD) of 2.6 nM, and rapid response time (~ 1.5 min), outperforming many existing single-signal fluorescent systems. Stability assessments confirmed robust optical performance under varying pH, ionic strength, and UV exposure conditions, though long-term storage stability remains to be evaluated. The probe's high selectivity for melamine was validated against common food matrix interferents. Furthermore, practical applicability was demonstrated by analyzing spiked milk and infant formula samples, yielding satisfactory recoveries and precision, comparable to standard HPLC/UV methods. Overall, this ratiometric fluorescence platform offers a sensitive, rapid, and user-friendly approach for melamine monitoring, with potential for adaptation to other food safety applications through surface modification or doping strategies.

PMID:40719877 | DOI:10.1007/s00604-025-07422-4

J Chromatogr A. 2025 Sep 27;1759:466230. doi: 10.1016/j.chroma.2025.466230. Epub 2025 Jul 17.

ABSTRACT

A novel adsorbent named as MS@CTFs, was successfully synthesized through the Schiff base reaction by immobilizing a covalent triazine framework (CTF) constructed from 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and trimethylformyl resorcinol (TP) onto a melamine sponge (MS) substrate. The innovative design integrated robust triazine-based CTF with an easy-to-use melamine sponge, simplifying the sample preparation procedure and also enhancing the adsorption performance. After optimizing the adsorption parameters, the MS@CTFs demonstrated robust adsorption for enrofloxacin (ENR) from milk matrices, the adsorption capacity was 155.3 mg g^-1. the LOD and LOQ were determined to be 0.032 μg mL^-1 and 0.107 μg mL^-1, respectively. Assessments conducted via GAPI, Complex GAPI, AGREE, and AGREEprep evaluation frameworks validated the method's outstanding environmental sustainability and operational feasibility with AGREE score of 0.67, AGREEprep score of 0.66. Furthermore, the MS@CTFs exhibited highly selective affinity towards cationic dyes. This study underscores the potential of the MS@CTFs as a selective adsorbent with nearly 100 % removal efficiency for the removal of ENR and cationic dyes from aqueous environments, contributing to advancements in milk and water treatment technologies.

PMID:40712455 | DOI:10.1016/j.chroma.2025.466230

J Environ Manage. 2025 Sep;391:126647. doi: 10.1016/j.jenvman.2025.126647. Epub 2025 Jul 19.

ABSTRACT

The challenge of recovering conventional photocatalysts has been addressed by the development of floating variants. However, the underlying molecular mechanisms governing the photocatalytic inactivation of hazardous algae remain poorly understood. This study employed a floating photocatalyst, melamine sponge-loaded bismuth trioxide coupled copper metal-organic framework (MS/Bi₂O₃@Cu-MOF), to efficiently inactivate a representative marine toxic alga, Karenia mikimotoi (K. mikimotoi), under visible light irradiation. Concurrently, Data-Independent Acquisition (DIA) proteomics was systematically applied to investigate differential protein expression throughout the photocatalytic inactivation process. At a loading amount of 0.4 g, an inactivation rate of K. mikimotoi reaching 99.306 % was achieved within 12 h. The MS/Bi₂O₃@Cu-MOF treatment group exhibited significant reductions in the three primary photosynthetic pigments and soluble protein. Furthermore, the relative content of reactive oxygen species (ROS) peaked at 681.45 % at 3 h before declining. Conversely, the specific activities of three key antioxidant enzymes demonstrated substantial increases. Differential protein enrichment analysis revealed that photocatalysis primarily affected the expression of proteins in K. mikimotoi associated with superoxide dismutase (SOD), peroxidase (POD), as well as proteins involved in calcium and potassium ion binding/transport and phospholipid binding. Gene ontology (GO) enrichment analysis revealed that the predominant functional category among the differentially expressed proteins (DEPs) was associated with metal ion binding. Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis further identified significant involvement of these DEPs in photosynthetic processes within K. mikimotoi. Collectively, this study provides an experimental foundation and theoretical insights at the protein level for understanding the photocatalytic inactivation of harmful algae, offering practical insights for advancing photocatalytic technology in real-world applications.

PMID:40684592 | DOI:10.1016/j.jenvman.2025.126647

Anal Methods. 2025 Jul 24;17(29):6133-6141. doi: 10.1039/d5ay00765h.

ABSTRACT

Melamine (MEL) is frequently adulterated in dairy products to manipulate protein content test results due to its high nitrogen content. In this study, a fluorescent probe based on ofloxacin (OFL) and gold nanoparticles (AuNPs) was proposed for the specific and sensitive detection of MEL. In the pH range of 4.5-7.5, the fluorescence spectrum of OFL exhibits a high degree of overlap with the absorption spectrum of AuNPs, and interactions based on fluorescence resonance energy transfer (FRET) occur, with significant quenching of OFL fluorescence accompanied by a change in fluorescence lifetime. After being incorporated into MEL, the amino group of MEL specifically interacted with the surface of AuNPs through coordination. This interaction triggered the aggregation of AuNPs, which in turn led to the fluorescence recovery of OFL. The detection of melamine was accomplished by quantifying the change in fluorescence intensity of OFL. Under optimized conditions, the MEL concentration exhibited a strong linear relationship with the relative fluorescence intensity of the probe (R² = 0.994) within a range of 0.1 to 1.6 μM. The limit of detection was determined to be 7.28 nM. It is noteworthy that the method was validated in real milk samples, with recovery rates ranging from 98.2% to 107.1%. The method exhibits excellent selectivity and sensitivity for MEL, making it a suitable tool for the environmental detection of milk.

PMID:40663392 | DOI:10.1039/d5ay00765h

Food Chem. 2025 Jul 7;492(Pt 2):145466. doi: 10.1016/j.foodchem.2025.145466. Online ahead of print.

ABSTRACT

Melamine, a nitrogen-rich industrial compound, is often illegally added to food products-especially dairy, to artificially inflate protein content, posing serious health risks such as kidney damage upon long-term exposure. This study aims to develop a fluorescence-based sensor for the sensitive detection of melamine. Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized using Murraya koenigii leaves via a green, microwave-assisted method. Resulting N-CQDs exhibited a high fluorescence-quantum-yield of 30 %, and their structural and optical characteristics were thoroughly analysed using appropriate techniques. Detection mechanism is based on dynamic fluorescence quenching, allowing for highly responsive melamine-sensing with a low detection limit of 0.385 μM. When applied to real samples like water and milk, sensor demonstrated excellent performance, achieving recovery rates between 96.8 % and 101.8 % with low relative standard deviations (0.70 %-4.34 %). Results suggest that developed sensor is a promising tool for rapid, green, and sensitive detection of melamine in food safety and environmental monitoring.

PMID:40645049 | DOI:10.1016/j.foodchem.2025.145466

Environ Health. 2025 Jul 9;24(1):47. doi: 10.1186/s12940-025-01201-7.

ABSTRACT

Pregnant women are regularly exposed to a variety of environmental toxicants in daily life, posing a potential threat of kidney injury before presence of clinical manifestations. As there is a paucity of studies employing an exposome-based approach of kidney health in pregnant women, this study utilizes the above-mentioned strategy to identify the most significant environmental toxicants associated with early kidney injury in pregnant women in the cohort of TMICS (Taiwan Maternal and Infant Cohort Study). A total of 1,139 third-trimester pregnant women (weeks 29-40) were recruited between 2012 and 2015, and one-spot urine samples were successfully collected for study. Sixteen biomonitoring chemicals were measured in urine, including exposure measurements of melamine, 9 phthalate metabolites, nonylphenol (NP), bisphenol A (BPA), methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP), and outcome measurements of NAG (N-acetyl-β-d-glucosaminidase) and albumin-to-creatinine ratio (ACR). A two-tier strategy of statistical analyses was employed and data was randomly and evenly split to both training (n = 569) and validation (n = 570) sets. Using a weighted quantile sum (WQS) regression in the training set and subsequently a multivariate regression in the validation set, we found that NP was the most important chemical to link with early markers of kidney injury, both ACR and NAG. Our findings indicate that short-term exposure to NP is associated with markers of subclinical kidney injury in pregnant women in Taiwan. Further research is warranted to determine whether NP exposure is linked to clinically relevant kidney outcomes.

PMID:40635015 | PMC:PMC12243187 | DOI:10.1186/s12940-025-01201-7

Food Chem X. 2025 Jun 13;29:102663. doi: 10.1016/j.fochx.2025.102663. eCollection 2025 Jul.

ABSTRACT

Plant-based materials are increasing been used as an alternative to conventional plastic materials in food packaging applications. Thus, for example, bamboo-based food contact articles are gaining popularity owing to their environmentally friendly connotations. However, the evaluation of its safety has been barely addressed. Components of these materials can migrate into the food leading to consumer exposure. Their identification is key for risk evaluations. In the present study, the chemical composition of a great variety of bamboo-based food contact articles including plates, chopsticks, etc. was explored. The volatile and semi-volatile fractions were analysed by gas chromatography-mass spectrometry (GC-MS). Volatile components were concentrated in a Purge & Trap system and semi-volatile compounds were analysed after a methanol extraction. A great diversity of compounds was tentatively identified, some considered toxic (e.g., 5-hydroxymethylfurfural). In addition, a sample suspected of containing melamine was analysed by LC-MS and melamine and its derivatives were detected.

PMID:40599599 | PMC:PMC12212174 | DOI:10.1016/j.fochx.2025.102663

Carbohydr Polym. 2025 Jul 15;360:123598. doi: 10.1016/j.carbpol.2025.123598. Epub 2025 Apr 11.

ABSTRACT

Polyamide 66 (PA66), a key polymer in numerous industries, struggles with fire resistance in world spread, emitting toxic gases, smoke, and molten drips, with mechanical properties constrained by required high loading. Herein, we designed a flower-like bio-based three-hybrid flame retardant, synthesized cellulose nanocrystals (CNC) with melamine polyphosphate (MPP) and zinc borate (ZB) through successive grafting and electrostatic adsorption processes. This innovative fire-extinguish composite forms spherical arrangement structure within PA66, and noncombustible gas and protective phase on exposure to fire, significantly enhancing PA66's flame retardancy, mechanical properties, and UV resistance. Incorporating 15 wt% flame retardant, the PA66 composite remarkably improves LOI to 28.7 % and V-0, and reduces peak heat release rate to 210.56 kW/m², 75 % lower than neat PA66. Surprisingly, its mechanical properties were substantially improved with a 225 % and 317 % increase in tensile stress and tensile strain, respectively. This strategy has the potential to establish a fire-safe and highly efficient application environment for PA66, thereby ensuring the protection of human life and property.

PMID:40399011 | DOI:10.1016/j.carbpol.2025.123598

Int J Environ Health Res. 2025 May 18:1-14. doi: 10.1080/09603123.2025.2503475. Online ahead of print.

ABSTRACT

This study investigated the relationship between maternal behaviours, environmental exposures, and the levels of melamine and bisphenols (BPs), including bisphenol F (BPF), bisphenol A-F (BPAF), and bisphenol S (BPS), in breast milk. Mothers provided information on cosmetic use, food packaging, and dietary habits, while breast milk samples were analyzed using high-performance liquid chromatography. BPAF, BPS, and BPF were detected in 32.3%, 33.8%, and 20% of samples, respectively, while melamine was present in all samples (mean: 32.3 ± 16.7 ng/mL). Seven samples (10.8%) contained all three BPs, while 49.2% had none. Higher BPAF and BPF levels were observed in breast milk from mothers aged 30-34. Makeup use was associated with elevated BPAF levels (p = 0.013), while sunscreen use was correlated with increased BPF (p = 0.040) and melamine (p = 0.010) levels. Storing oil in plastic containers was linked to higher BPS levels. These findings suggest that maternal exposure to personal care products and food packaging materials significantly influences BPs and melamine levels in breast milk. The results highlight the importance of considering both behavioural and environmental factors when assessing chemical exposure during breastfeeding. Further research is needed to understand the long-term effects of these exposures on infant health.

PMID:40383959 | DOI:10.1080/09603123.2025.2503475

Mikrochim Acta. 2025 May 14;192(6):352. doi: 10.1007/s00604-025-07209-7.

ABSTRACT

This study presents the first demonstration of a photothermal-based paper analytical device (PT-PAD) for melamine monitoring in milk samples. The sensor utilizes plasmonic gold nanoparticles (AuNPs) as effective photothermal materials to enable melamine detection. In our technique, melamine induces the aggregation of AuNPs on the paper substrate, resulting in a temperature change proportional to melamine levels. This temperature variation can be measured using a portable and inexpensive thermometer, enhancing affordability. The sensor provides a linear range between 125.0 and 1500.0 ng mL^-1 with a R² value of 0.9965 and a detection limit of 27.0 pg mL^-1. It demonstrates excellent selectivity with no observed interference, and achieves high accuracy and precision in real milk samples, with recoveries between 97.3 and 108.5% and a maximum RSD of 7.5%. The results are statistically comparable to HPLC, confirming the method's reliability. Furthermore, while the assay requires only low-cost commercial tools such as a laser pointer and a thermometer, its detection efficiency is significantly higher than other previous PAD methods for melamine detection. Overall, our developed PT-PAD sensor is well-suited for monitoring melamine levels in milk samples, offering advantages such as affordability, sensitivity, and ease of use. The approach also presents a promising platform for future expansion into other analytes by integrating plasmonic nanomaterials with microfluidic technologies, broadening its application across food safety and environmental monitoring.

PMID:40366462 | DOI:10.1007/s00604-025-07209-7

Food Chem Toxicol. 2025 Aug;202:115521. doi: 10.1016/j.fct.2025.115521. Epub 2025 May 5.

ABSTRACT

Dairy products are exceptionally nutritious and a key component of our diet. They are utilized in a wide range of food industries due to their significance. However, being highly popular and valuable, they are among the most common products subject to adulteration. Melamine is a chemical compound deliberately added to various food products. It is used to artificially increase the apparent protein content in milk, milk powder, pet food, and other foods. In this study, pure milk powder along with 12 different types of adulterated samples (with melamine content of 1, 2, 3, 4, and 5 ppm) in both dry and wet forms was analyzed using an electronic nose equipped with 8 metal oxide sensors to detect adulteration patterns. Principal Component Analysis (PCA), discriminant analysis (DA), and Support Vector Machine (SVM) methods were employed to analyze sensor response patterns and classification. Quantitative Descriptive Analysis (QDA) yielded a precision of 99.5 %, while Multi-Discriminant Analysis (MDA) achieved a precision of 98.5 %. Therefore, it appears that electronic nose technology with metal oxide sensors, along with chemometric methods, can be a truly effective tool for the rapid detection and classification of pure milk powder from adulterated materials.

PMID:40334969 | DOI:10.1016/j.fct.2025.115521

Crit Rev Anal Chem. 2025 Apr 29:1-13. doi: 10.1080/10408347.2025.2496502. Online ahead of print.

ABSTRACT

Proteins contain amino acids, which are extremely important for healthy growth, muscle mass production, and improved quality of life. As a result, consumers' intake of insufficient amounts of protein, leads to a deterioration in body resistance, becoming vulnerable to diseases, muscle mass loss, and experiencing many adverse health conditions. It is more commonly used by athletes, particularly to enhance and speed up weight gain, and it is crucial for kids, the elderly, and patients who need to replace absent nutrients in their diet. As more people use protein powder supplements, sales are becoming more competitive, and numerous unauthorized producers have begun providing products that meet the need. Many protein supplements on the market are adulterated or contain undisclosed, inexpensive chemicals, causing discrepancies between labeled and actual amounts of active compounds, which is a growing issue. These include substances like rice, soybeans, urea, cheaper amino acids (e.g. L-glutamine and L-taurine), bulking agents like maltodextrin and cyanuric acid and, in some cases, even dilution with milk powder or melamine. It may be able to better regulate athletes' and patients' exposure to illegal substances and adulteration, safeguard the health of consumers by developing quick and precise ways to test protein supplements. This comprehensive review presents a variety of analytical approaches utilizing spectroscopic and chromatographic methods for the identification of additives for quality control and content verification purposes.

PMID:40300048 | DOI:10.1080/10408347.2025.2496502

Crit Rev Anal Chem. 2025 Apr 14:1-32. doi: 10.1080/10408347.2025.2477535. Online ahead of print.

ABSTRACT

Milk adulteration is a crucial worldwide concern that endangers food safety and public health, as it involves the deliberate tampering with milk by adding foreign substances or removing essential nutrients, often to boost profits or hinder microbial growth. Traditional detection methods frequently lack the sensitivity and speed required to identify adulterants within milk's complex matrix. This systematic review critically examines the application of spectroscopic techniques for detecting milk adulteration, focusing on Nuclear Magnetic Resonance (NMR), Infrared (IR) Spectroscopy, Raman Spectroscopy, Ultraviolet-Visible (UV-Vis) Spectroscopy, Mass Spectrometry, Laser-Based Techniques, Dielectric Spectroscopy, and X-Ray Spectroscopy. Each technique's principles, advantages, limitations, and specific applications in identifying adulterants, such as water, urea, melamine, added sugars, fats, preservatives, and heavy metals are discussed. The review highlights how these methods offer rapid, non-destructive, and sensitive analysis, enhancing the ability to detect adulterants at molecular levels. Despite advancements, challenges persist, including the complexity and natural variability of milk composition, high costs of advanced equipment, need for specialized expertise, and lack of standardized protocols. Future directions emphasize developing portable and cost-effective spectroscopic devices, integrating artificial intelligence and machine learning for advanced data analysis, and fostering international collaboration to establish standardized methodologies and comprehensive spectral databases. By addressing these challenges, spectroscopic techniques can be more widely implemented, ultimately safeguarding public health, ensuring the integrity of dairy products, and maintaining consumer trust in the global food supply chain.

PMID:40227776 | DOI:10.1080/10408347.2025.2477535

Spectrochim Acta A Mol Biomol Spectrosc. 2025 Oct 5;338:126156. doi: 10.1016/j.saa.2025.126156. Epub 2025 Apr 1.

ABSTRACT

We present a novel, cost-effective SERS substrate for melamine detection in milk. Melamine is a nitrogen-rich compound illegally used to indicate high protein content. We developed a hybrid substrate based on molecularly imprinted polymer nanobeads functionalized with graphene oxide (MIP nanobeads@fGO). MIPs act as a door for selective detection and provide chemical enhancement. fGO achieves further chemical enhancement of the Raman signal by bond-making through functionalized moieties and electrostatic interaction with the ring moiety of fGO with melamine in SERS. Prior to polymerization, the molecular interaction between vinyl imidazole (VIM) as a functional monomer and melamine as a target molecule was modeled using AutoDockTools GUI (Graphical User Interface) and AutoGrid for molecular modelling simulations and grid calculations. From the clustering histogram, melamine and VIM molecules had the lowest binding energy of -0.77 kcal/mol. Also, the free energy of Melamine-VIM interaction at 298.15 K was -2729.21 kcal/mol, which is evidence that the interaction was energetically favorable. The fGO and MIP nanobeads@fGO were characterized by various techniques including FTIR and RAMAN spectroscopy, DSL and SEM. The SERS performance of MIP nanobeads@fGO was analyzed and showed excellent performance towards melamine with an EF of 1.3 × 10⁶ and good reproducibility with an RSD of 8.3 %. A good correlation was observed between the -log concentration of melamine (μM) and the Raman intensity (a.u.) in a broad linear range from 7.9 E-5 μM to 7.9 E2 μM, with LOD and LOQ of 1.2 μM (0.15 ppm) and 3.6 μM (0.45 ppm), respectively. The USFDA and WHO introduced the tolerable level of melamine in milk and dairy products at no >2.5 ppm. Our LOD is below the tolerable limit, indicating that the MIP nanobeads@fGO substrate can be effectively used for food safety analysis in milk samples.

PMID:40209451 | DOI:10.1016/j.saa.2025.126156

Environ Pollut. 2025 Jun 1;374:126206. doi: 10.1016/j.envpol.2025.126206. Epub 2025 Apr 8.

ABSTRACT

Studies concerning the effect of co-exposure to melamine and phthalates on kidney function in children are rare. Thus, this study examines the above-mentioned relationship and their sex-different effect. Whether the exposure of the two chemicals from their mothers, when children were in the womb during the third trimester, affected renal injury markers in children afterwards is also examined. This study was from Taiwan Maternal and Infant Cohort Study cohort established in October 2012 to enroll third-trimester pregnant mothers up to May 2015. Their offspring were subsequently recruited between 2016 and 2020 as our study children. One-spot urine specimens were collected from both pregnant mothers (2012-2015) and study children (2016-2020) for the simultaneous measurement of melamine and 11 phthalate metabolites. Daily intakes of melamine and five phthalates, including DEHP (di-2-ethylhexylphthalate), DiBP (Dibutyl phthalate), DnBP (Di-n-butyl phthalate), BBzP (Butyl benzyl phthalate), and DEP (Diethyl phthalate), were estimated using a creatinine excretion-based model in both study children and their mothers. Two early markers of renal injury, microalbumin and N-acetyl-beta-D-glucosaminidas (NAG), were measured in urine samples of study children (2016-2020). A total of 552 eligible children were studied, with a mean age of 4 years. We found that boys in the highest quartile of estimated melamine intake (≥0.68 μg/kg/day) had significantly higher urine ACR levels and in the highest quartile of estimated phthalate intake of DEHP (≥5.36 μg/kg/day), DEP (≥0.89 μg/kg/day), and DiBP (≥1.19 μg/kg/day) had significantly higher urine NAG levels when compared to the combined three lowest quartile ones as comparison groups. No significant associations were found between their mothers' phthalates and melamine intake during the third trimester and urine ACR and NAG in children. We conclude that children (particularly boys) with high co-exposure of melamine and certain phthalate chemicals among children have increased early markers of kidney injury.

PMID:40210160 | DOI:10.1016/j.envpol.2025.126206

Food Sci Nutr. 2025 Apr 7;13(4):e70081. doi: 10.1002/fsn3.70081. eCollection 2025 Apr.

ABSTRACT

Illegal melamine analogs are added to food to make it appear as though it contains more protein. These substances have negative impacts on both humans and animals in high quantities. The present paper examines how cobra venom shields rats from melamine-induced hepatotoxicity. The current study was conducted on six groups of adult male rats, as follows: group I (negative control): I.P. injected with distilled water, group II (SV10 μg/kg):I.P injected with 10 μg/kg cobra venom, group III (SV20 μg/kg): I.P. injected with 20 μg/kg cobra venom, group IV (melamine): orally 700 mg/kg melamine, group V (melamine + SV10 μg/kg): treated with 10 μg/kg cobra venom, group VI (melamine + SV20 μg/kg): treated with 20 μg/kg cobra venom. Treatment with snake venom ameliorated liver functions and increased apoptotic level marker Caspase-3, decreased anti-apoptotic level marker BAX. Also, decreased inflammatory level marker IL-2 and expression level of IL-10, INF-γ. treatment with snake venom ameliorated hepatotoxicity induced by melamine in albino rats.

PMID:40196227 | PMC:PMC11973453 | DOI:10.1002/fsn3.70081

Toxics. 2025 Feb 25;13(3):161. doi: 10.3390/toxics13030161.

ABSTRACT

In the manufacture of infant formulas, from raw materials to the final product, the ingredients are subject to high temperatures which favor the formation of undesirable compounds, some of them from the Maillard reaction, such as 5-hydroxymethylfurfural (HMF) and acrylamide, and others from thermal processing, such as the compound 3-monochloro-1,2-propanoldiol (3-MCPD). Finally, there is also a risk that the product may be adulterated with undesirable components such as melamine and cyanuric acid. Due to the vulnerability of infants during the first stage of life, this review answers the main question: How much of these undesirable compounds are present in commercial infant formulas, and what do we know about them? Accordingly, the review is divided into three sections: (1) Maillard reaction products (HMF and acrylamide), (2) products contained in vegetable oils (3-MCPD), and (3) fraudulent and/or adulterant compounds (melamine and cyanuric acid). The objective is to report on the occurrence of HMF, acrylamide, 3-MCPD, melamine, and cyanuric acid in infant formulas in order to support more solid public health policies related to infant feeding. These undesirable compounds represent a risk to infants, possibly contributing to kidney and neurological damage and causing mutations that increase the development of childhood cancer. Therefore, it is necessary to promote breastfeeding and establish stricter controls, with scientific evidence on the effects of HMF, acrylamide, 3-MCPD, melamine, and cyanuric acid in infant formulas to reduce their short- and long-term effects on infants' health.

PMID:40137488 | PMC:PMC11946680 | DOI:10.3390/toxics13030161

Oncol Res. 2025 Feb 28;33(3):665-674. doi: 10.32604/or.2024.054487. eCollection 2025.

ABSTRACT

OBJECTIVES: Due to systematic side effects, there is a growing interest in nanoparticle formulation of anticancer drugs. Here, we aimed to synthesize poly (styrene-alt-maleic anhydride) cross-linked by melamine (PSMA/Me) and coated with magnetite nanoparticles (MNPs) PSMA/Me/Fe₃O₄. In addition, we aimed to load paclitaxel (PTX) into PSMA/Me/Fe₃O₄ for drug delivery and anticancer investigations.

METHODS: Novel PSMA/Me was synthesized via free radical copolymerization, coated with Fe₃O₄, and then used as a transporter for PTX delivery. Fabricated copolymer was characterized using SEM, TGA, and XRD techniques. Drug release rate and loading efficiency were investigated. Human ovarian cancer cells (Skov-3) and breast cancer cells (MCF-7 cells) were incubated with the serial concentration of either free PTX or PSMA/Me/Fe₃O₄/PTX for cell viability and IC₅₀ analysis for 24 and 48 h.

RESULTS: Characterization methods confirmed PSMA/Me copolymer formation. The results showed a significant encapsulation efficiency of 83%. The drug release analysis exhibited that PSMA/Me/Fe₃O₄/PTX may be considered pH-sensitive nanocarriers. PSMA/Me/Fe₃O₄/PTX reduced cell viability both dose and time-dependently (p < 0.05). IC₅₀ values of PSMA/Me/Fe₃O₄/PTX were low when compared to free PTX either 24 or 48 h post-treatment.

CONCLUSIONS: Our results indicated that PSMA/Me/Fe₃O₄/PTX was more cytotoxic than PTX in both cancer cells. Findings indicated the potential of PSMA/Me/Fe₃O₄/PTX as an anticancer nanocarrier system.

PMID:40109872 | PMC:PMC11915072 | DOI:10.32604/or.2024.054487

Ecotoxicol Environ Saf. 2025 Mar 15;293:118029. doi: 10.1016/j.ecoenv.2025.118029. Epub 2025 Mar 14.

ABSTRACT

BACKGROUND: Within the past two decades, high-profile cases of melamine (MA) exposure have raised significant toxicological concerns, particularly regarding food adulteration. While widely used as a fundamental organic chemical intermediate in various household products, MA's potential for unexpected toxicological synergy with its homolog, cyanuric acid (CA), remains a concern. This study aimed to investigate the nephrotoxicity of combined melamine and cyanuric acid (MC) exposure and its underlying mechanisms in rats through an integrative approach, combining network toxicology (NT), bioinformatics, and experimental validation.

MATERIALS AND METHODS: Rats were exposed to MC at doses of 0/0 mg/kg/day (Control) and 63/63 mg/kg/day (MC) for four weeks. Kidney pathology, injury markers, and RNA sequencing (RNA-seq) data were analyzed to identify differentially expressed genes between the two groups. Bioinformatics analysis, including pathway enrichment and immune microenvironment analysis, was conducted to elucidate the underlying mechanisms of MC-induced kidney injury. Potential target proteins were identified using ChEMBL, STITCH, and GeneCards databases, and hub genes were screened using three machine learning algorithms: LASSO regression, Random Forest, and Molecular Complex Detection. Molecular docking simulations were performed to assess the interactions between MC and the identified hub genes.

RESULTS: MC exposure resulted in severe kidney morphological and histological changes, as well as elevated levels of kidney injury and fibrosis markers. RNA-seq analysis revealed significant enrichment of immuno-inflammatory and apoptosis-related pathways in the MC group. Immune microenvironment analysis confirmed the infiltration of pro-inflammatory immune cells. Network toxicology analysis identified 20 potential targets associated with MC-induced kidney injury. Two hub genes, Ren and Casp3, were identified as key regulators of the renin-angiotensin-aldosterone system (RAAS) activation and apoptosis, respectively. Further experimental validation, including Western blotting and immunofluorescence, confirmed the upregulation of these proteins. Molecular docking simulations demonstrated strong binding affinities between MC and the two hub proteins.

CONCLUSION: MC exposure induces significant kidney injury and fibrosis. The activation of the RAAS pathway and apoptosis plays a crucial role in MC-mediated nephrotoxicity. However, additional vivo experimental validation is lacking. Future studies should focus on further exploration for the mechanism of MC-induced nephrotoxicity and more rigorous experimental validation.

PMID:40088607 | DOI:10.1016/j.ecoenv.2025.118029

J Chromatogr A. 2025 May 10;1748:465850. doi: 10.1016/j.chroma.2025.465850. Epub 2025 Mar 6.

ABSTRACT

Based on the principle that poly(thymine) ssDNA could recognize melamine (Mel) in aqueous media and the third face of Mel could be accessed by other hydrogen bonding molecules, UiO-66-NH₂ was functionalized with poly(thymine) ssDNA and as the matrix to construct three-face recognition molecularly imprinted polymers (UDMIPs). The adsorption processes of UDMIPs towards Mel were accorded to Sips model and exhibited high adsorption capacity (Q_S=10.60 mg/g) and good imprinting factor (IF=2.67). UDMIPs could reach the adsorption equilibrium within 20 min. Competitive adsorption and regeneration experiments demonstrated that UDMIPs exhibited good selectivity and reusability. The adsorption machanism was investigated by CD spectroscopy. Combined with HPLC, UDMIPs were successfully employed to detect Mel in milk samples with recovery rates ranging from 88.4 % to 94.8 %.

PMID:40086143 | DOI:10.1016/j.chroma.2025.465850

Tissue Cell. 2025 Aug;95:102826. doi: 10.1016/j.tice.2025.102826. Epub 2025 Mar 1.

ABSTRACT

Melamine is a prevalent environmental toxicant associated with well-established toxicity on several organs. The adrenal gland is a highly dynamic organ that makes it susceptible to chemicals' toxicity. The current work investigated the adrenal histo-biochemical alterations caused by melamine exposure in rats and explored whether morin has protective potential against such adrenal toxicity. The experiment utilized 32 adult male Wistar rats randomly divided into control, morin, melamine, and melamine/morin groups. Adrenal toxicity was induced by melamine (126 mg/kg/d). Morin was used in a dose of 50 mg/kg/d. All treatments were given via oral gavage for 4 weeks. The adrenal oxidative stress markers, serum corticosterone (CORT), adrenocorticotrophic hormone (ACTH), and the mRNA expression of the steroidogenic genes; StAR (Steroidogenic acute regulatory protein), P450scc (Cholesterol side-chain cleavage enzyme), and11β-HSD1 (11β-Hydroxysteroid dehydrogenase type 1) were evaluated. Also, histological and immunohistochemical examinations of the paraffin-processed adrenal sections were performed. Melamine decreased adrenal tissue superoxide dismutase (SOD) and catalase (CAT) activities, increased adrenal malondialdehyde (MDA) levels, decreased serum CORT and increased ACTH levels, and suppressed the adrenal cortical expression of genes involved in steroidogenesis. Moreover, the inducible nitric oxide synthase (iNOS) and cysteine-aspartic acid protease-3 (caspase-3) expression were upregulated as indicated by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) and immunohistochemistry. Besides, melamine caused remarkable adrenal histopathological changes. However, morin administration greatly repaired the adrenal injury and restored the adrenal function. Morin maintained the adrenal histoarchitecture and protected against melamine-provoked adrenal toxicity by downregulating the inflammation and the adrenal apoptotic processes and relieving the oxidative stress burden.

PMID:40056657 | DOI:10.1016/j.tice.2025.102826

Food Chem X. 2025 Feb 3;26:102254. doi: 10.1016/j.fochx.2025.102254. eCollection 2025 Feb.

ABSTRACT

Melamine contamination in food poses significant health risks including kidney stones, renal failure, making it a critical food safety concern. This study investigated the presence of melamine contamination in commercial citrus juices and its exposure through citrus juice. Samples were selected from different packaging. Melamine concentrations in commercial juice samples varied significantly, ranging from 1.732 mg/L in lemon juice to 31 mg/L in orange juice. The highest levels were found in products packaged in cardboard packaging. However, the risk assessment did not identify any risk for different ages. But, these findings highlight the need to monitor melamine levels in commercial juices.

PMID:39995402 | PMC:PMC11848499 | DOI:10.1016/j.fochx.2025.102254

Spectrochim Acta A Mol Biomol Spectrosc. 2025 May 15;333:125870. doi: 10.1016/j.saa.2025.125870. Epub 2025 Feb 8.

ABSTRACT

Non-halogenated flame-retardant Melamine (MEL), an alternative to toxic halogenated flame retardants, has been recognized as a substance of very high concern by the ECHA. Therefore, identifying MEL in plastic waste is essential for ensuring safe handling and recycling. This study presents industrial in-line quantitative identification techniques for MEL in low-density polyethylene (LDPE) and polypropylene (PP) via short-waved infrared (SWIR) hyperspectral imaging combined with machine learning. LDPE and PP samples with varying MEL loadings were compounded and characterized through elemental analysis, ATR-FTIR, TGA, and DSC. Regression on the SWIR band area ratio and principal component one was applied to the SWIR spectra to compile predictive models. The models performed equally well, demonstrating a strong correlation between measured and predicted MEL concentrations. The model based on SWIR band area ratio ranged from 0.8 to 29.8 wt% MEL in LDPE (R²_LDPE = 0.975) and 1.4 to 26.3 wt% MEL in PP (R²_PP = 0.995), while the model based on principal component one ranged from 0.8 to 29.8 wt% MEL in LDPE (R²_LDPE = 0.978) and 0.9 to 26.3 wt% MEL in PP (R²_PP = 0.988). Further, the hyperspectral in-line models perform comparably to FTIR band ratio ranging from 1.11 to 29.78 wt% MEL in LDPE and 1.40 to 26.26 wt% MEL in PP. The proposed methods can facilitate real-time monitoring of MEL concentrations in plastic and enable detection below hazardous threshold limits, which is crucial in the recycling industries.

PMID:39952067 | DOI:10.1016/j.saa.2025.125870

Chemosphere. 2025 Feb;370:143918. doi: 10.1016/j.chemosphere.2024.143918. Epub 2024 Dec 10.

ABSTRACT

Melamine has a high production volume today and is spread ubiquitously in the anthropogenic technosphere. It is released steadily to the water cycle by many sources. Even though melamine has low direct toxicity, chronic exposure can cause nephrolithiasis and disrupt the endocrine system. Most data on melamine is based on case studies with, when compared, partially contradictive implications. As melamine is a compound of many sources (SMS), very persistent, mobile (vPvM), and toxic (PMT) it has the potential to break through natural barriers posing a potential risk to drinking water resources. This study combines existing data with own measurements gathered through various individual monitoring campaigns with the aim to gain new insights into its environmental behaviour and hotspots. Samples from surface water bodies, groundwater, wastewater (treated, untreated), and soil samples were analysed regarding their melamine concentration via liquid chromatography coupled with tandem mass spectrometry (LC-MSMS). Besides three drinking water samples, melamine could be found in all water samples (n = 632) of this study, with a maximum concentration of 1289 ng/L in drinking water and 1120 ng/L in groundwater. While a constant baseline melamine concentration with an event-based release could be observed in most surface water bodies, higher concentrations towards Western Europe (urbanisation and chemical industry) was observed for wastewater. A similar pattern was found in the spatial distribution of melamine in agricultural soils towards an urban/suburban area. As, in general, melamine concentrations were higher towards urbans centers melamine can also be classified as an indicator of anthropogenic activity and urbanisation, but also spotlights on these areas as hotspots for potentially many compounds of the human technosphere. We call policy to shift from the existing one-size-fits-all solution to more flexible and risk-based approaches to prepare for future challenges.

PMID:39647792 | DOI:10.1016/j.chemosphere.2024.143918

Environ Sci Technol. 2024 Apr 16;58(15):6814-6824. doi: 10.1021/acs.est.4c00577. Epub 2024 Apr 6.

ABSTRACT

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.

PMID:38581381 | DOI:10.1021/acs.est.4c00577

Environ Sci Technol. 2023 Oct 3;57(39):14694-14706. doi: 10.1021/acs.est.3c02945. Epub 2023 Sep 21.

ABSTRACT

Persistent, mobile, and toxic (PMT) substances are affecting the safety of drinking water and are threatening the environment and human health. Many PMT substances are used in industrial processing or consumer products, but their sources and emissions mostly remain unclear. This study presents a long-term source distribution and emission estimation of melamine, a high-production-volume PMT substance of emerging global concern. The results indicate that in China, approximately 1858.7 kilotonnes (kt) of melamine were released into the water (∼58.9%), air (∼27.0%), and soil systems (∼14.1%) between 1995 and 2020, mainly from its production and use in the decorative panels, textiles, and paper industries. The textile and paper industries have the highest emission-to-consumption ratios, with more than 90% emissions per unit consumption. Sewage treatment plants are the largest source of melamine in the environment for the time being, but in-use products and their wastes will serve as significant melamine sources in the future. The study prompts priority action to control the risk of PMT substances internationally.

PMID:37734035 | PMC:PMC11017250 | DOI:10.1021/acs.est.3c02945

Huan Jing Ke Xue. 2023 Jun 8;44(6):3017-3023. doi: 10.13227/j.hjkx.202207182.

ABSTRACT

Persistent, mobile, and toxic or very persistent and very mobile (PMT/vPvM) chemicals have been widely detected in surface water, groundwater, and drinking water around the world and are important emerging contaminants that may significantly affect human health and the environment in the future. According to the identification criteria proposed by the European Union, there are thousands of PMT/vPvM substances in existing chemicals, covering a wide range of applications, including dozens of high-yield industrial chemicals such as melamine. PMT/vPvM chemicals can be discharged into the environment through farmland runoff, industrial wastewater, and domestic sewage, and sewage treatment plants are currently considered to be their main discharge route. It is difficult to effectively remove PMT/vPvM chemicals through the current conventional water treatment technology; they can exist in the water circulation system of the urban human settlement environment for a long time, endangering the safety of drinking water and the ecosystem. The European Union has taken the lead in introducing PMT/vPvM chemicals specifically into the priority areas of the current chemical risk management system. At present, there are still many potential PMT/vPvM chemicals in the environment, and their monitoring methods need to be further improved. It will take time for the identification of substances, the scope of categories, and the establishment of lists. Studies on the environmental fate and exposure of PMT/vPvM in various regions of the world are still very limited, and research on the potential, long-term ecotoxicity, and human health hazard effects remains scarce. At the same time, the research and development of substitute or alternative technologies, as well as environmental engineering treatment technologies such as sewage treatment and contaminated site remediation, will become an urgent need for future PMT/vPvM risk scientific research and management decisions.

PMID:37309920 | DOI:10.13227/j.hjkx.202207182

Sci Total Environ. 2023 Sep 20;892:164264. doi: 10.1016/j.scitotenv.2023.164264. Epub 2023 May 19.

ABSTRACT

Green infrastructure drainage systems are innovative treatment units that capture and treat stormwater. Unfortunately, highly polar contaminants remain challenging to remove in conventional biofilters. To overcome treatment limitations, we assessed the transport and removal of stormwater vehicle-related organic contaminants with persistent, mobile, and toxic (in short: PMTs) properties, such as 1H-benzotriazole, NN'-diphenylguanidine, and hexamethoxymethylmelamine (PMT precursor), using batch experiments and continuous-flow sand columns amended with pyrogenic carbonaceous materials, like granulated activated carbon (GAC) or wheat-straw derived biochar. Our results indicated that all investigated contaminants were subjected to nonequilibrium interactions in sand-only and geomedia-amended columns, with kinetic effects upon transport. Experimental breakthrough curves could be well described by a one-site kinetic transport model assuming saturation of sorption sites, which we inferred could occur due to dissolved organic matter fouling. Furthermore, from both batch and column experiments, we found that GAC could remove contaminants significantly better than biochar with higher sorption capacity and faster sorption kinetics. Hexamethoxymethylmelamine, with the lowest organic carbon-water partition coefficient (K_OC) and largest molecular volume among target chemicals, exhibited the lowest affinity in both carbonaceous adsorbents based on estimated sorption parameters. Results suggest that sorption of investigated PMTs was likely driven by steric and hydrophobic effects, and coulombic and other weak intermolecular forces (e.g., London-van der Waals, H-bonding). Results from extrapolating our data to a 1-m depth geomedia-amended sand filter suggested that GAC and biochar could enhance the removal of organic contaminants in biofilters and last for more than one decade. Overall, our work is the first to study treatment alternatives for NN'-diphenylguanidine and hexamethoxymethylmelamine, and contributes to better PMT contaminant removal strategies in environmental applications.

PMID:37209730 | DOI:10.1016/j.scitotenv.2023.164264

Environ Sci Technol. 2022 Aug 2;56(15):10857-10867. doi: 10.1021/acs.est.2c03659. Epub 2022 Jul 22.

ABSTRACT

Persistent, mobile, and toxic (PMT) and very persistent and very mobile (vPvM) substances have been recognized as a threat to both the aquatic environment and to drinking water resources. These substances are currently prioritized for regulatory action by the European Commission, whereby a proposal for the inclusion of hazard classes for PMT and vPvM substances has been put forward. Comprehensive monitoring data for many PMT/vPvM substances in drinking water sources are scarce. Herein, we analyze 34 PMT/vPvM substances in 46 surface water, groundwater, bank filtrate, and raw water samples taken throughout Germany. Results of the sampling campaign demonstrated that known PMT/vPvM substances such as 1H-benzotriazole, melamine, cyanuric acid, and 1,4-dioxane are responsible for substantial contamination in the sources of German drinking water. In addition, the results revealed the widespread presence of the emerging substances 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and diphenylguanidine (DPG). A correlation analysis showed a pronounced co-occurrence of PMT/vPvM substances associated predominantly with consumer or professional uses and also demonstrated an inhomogeneous co-occurrence for substances associated mainly with industrial use. These data were used to test the hypothesis that most PMT/vPvM substances pass bank filtration without significant concentration reduction, which is one of the main reasons for introducing PMT/vPvM as a hazard class within Europe.

PMID:35868007 | DOI:10.1021/acs.est.2c03659