Microplastics

Plastic waste is estimated to represent 40–80% of the total amount of marine litter, with polyethylene (PE) and polypropylene (PP) being the most abundant polymeric components. The recovery and recycling of marine plastic debris are therefore essential to mitigate environmental pollution and limit the generation of secondary microplastics. In this work, a mechanical recycling strategy was investigated for the valorization of a polyethylene-rich plastic fraction (PE-rf) recovered from the marine environment, characterized by high heterogeneity and persistent inorganic contamination. Different pre-treatment routes, including cryogenic grinding and planetary ball milling, as well as blending approaches with recycled polyethylene and compatibilizing additives, were explored. The effects of composition and processing on the thermal, mechanical, and morphological properties of the resulting materials were systematically analyzed. The results show that intense mechanical homogenization and chemical compatibilization are not sufficient to overcome the intrinsic limitations imposed by contamination and compositional variability. As a proof of concept, selected formulations were processed into filaments and tested in fused filament fabrication, demonstrating basic 3D printability. Full article

Microplastics (MPs), i.e., plastic particles <5 mm, and nanoplastics (NPs), i.e., plastic particles <1 µm, are widespread in the environment. MPs and NPs (MNPs) have also been detected in human tissues. Environmental MNPs exhibit diverse physicochemical properties such as size, shape, and surface degradation. However, most experimental studies have used pristine MNPs, which poorly represent real-world conditions, and only a limited number of studies have focused on preparing environmentally relevant MNPs. Therefore, we focused on the key physicochemical properties of MNPs, particularly their shape, size, and surface degradation, using polyvinyl chloride (PVC) as the model polymer. In this study, fragment and spherical PVC-MNPs were utilized, and surface degradation was introduced through exposure to vacuum ultraviolet (VUV) radiation at a wavelength of 172 nm. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) analysis revealed the formation of additional carbonyl groups after VUV exposure. We investigated the cytotoxic effects of the degraded and non-degraded PVC-MNPs on A549, Caco-2, and THP-1 cells. The results indicated that the degraded PVC-MNP-treated groups induced higher cytotoxic effects than those in the non-degraded groups. Notably, the degraded PVC-NPs induced stronger cytotoxicity than the degraded PVC-MPs. These findings highlight the potential health risks associated with environmental MNPs. Full article

This study investigates the sorption process of selected pollutants, namely naphthalene (NAP), pentachlorophenol (PCP), sulfamethoxazole (SMX), and ibuprofen (IBU), onto different real microplastics (MPs) under controlled laboratory conditions. Sorption tests reveal variable affinities depending on the chemical and physical interactions between polymers and pollutants. NAP showed the greatest uptake on the majority of tested MPs, followed by PCP and SMX, while IBU exhibited negligible sorption. Kinetic tests indicate a general rapid initial uptake, followed by lower sorption rates leading to equilibrium within days. Theoretical thermodynamic affinity estimations, based on the Hansen solubility parameter (HSP) method, previously tested only on antibiotics, are applied for the first time to commercial MPs and several pollutant categories such as PAHs, pesticides and other pharmaceuticals. Predictions have been validated with experimental results and generally show very good agreement with the affinity ranking derived by experimental data. However, some limitations occur due to the heterogeneity of the real MPs and different environmental conditions. Factors affecting, to different extents, MPs’ uptake include hydrophobicity and electrostatic forces, as well as pH and particle size. This work advances understanding of MPs’ role as vectors of pollutants in aquatic environments and validates the use of an innovative combined experimental–theoretical approach useful as a tool to predict associated risk. Full article

Microplastic (MP) contamination is increasingly recognized as a global environmental problem affecting aquatic ecosystems, food quality, and animal and human health. Farmed fish represent an important and increasing component of the human diet. Therefore, understanding potential human exposure to MPs is essential for ensuring food safety. In the current paper, we present the results of a preliminary study conducted in Bulgaria on MP contamination in the muscle tissue of rainbow trout [Oncorhynchus mykiss (Walbaum, 1792)] reared in freshwater aquaculture systems. Edible tissues were analyzed using Laser Direct Infrared (LDIR) imaging spectroscopy, a highly sensitive method enabling rapid detection and accurate identification of polymer types present in samples. MPs were detected in all examined specimens, demonstrating that these particles are bioavailable and capable of accumulating in fish muscle tissues commonly consumed by humans. Moreover, the presence of multiple polymer types suggests diverse contamination sources within aquaculture environments. Although the present findings do not allow direct conclusions about human health risks, they indicate potential risks of trophic transfer and highlight the need for improved monitoring strategies and management practices in farmed fish production. Overall, this study provides novel data on MP exposure in aquaculture species and emphasizes the preventive importance of assessing plastic pollution in fish intended for human consumption. Full article

Introduction: It is accepted that nano- and micro-plastic (NMP) pollutants threaten ecosystems and human health by their bioaccumulation but, interestingly, their toxicity is shape-dependent. However, a clear definition of irregular NMPs, as the dominant shape in environmental and biological samples, is currently lacking when compared to spherical and fibrous NMPs. Objectives: This study quantifies morphometric descriptors in order to develop a standardized definition for irregular NMPs. Methods: Hyperspectral images of 34 spherical, 50 fibrous, and 45 irregular NMPs were collected from the literature. All shape-related features reported previously were analyzed using a machine learning model. Using five-fold cross-validation, a decision tree-based ensemble classifier with fixed parameters and Gini coefficient was established to screen key morphometric descriptors and their optimal interval ranges. The model was independently validated, enabling the accurate distinction of irregular NMPs from spherical and fibrous NMPs. Results: Three morphometric descriptors, including circularity, roundness, and perimeter-to-area ratio, were identified using five-fold cross-validation as optimal indicators for NMP shape classification. Optimal interval ranges for irregular NMPs were as follows: circularity (0.388 ± 0.004–0.768 ± 0.004), roundness (0.248 ± 0.01–0.752 ± 0.06) and perimeter-to-area ratio (>11.608 ± 1.39). This approach generated a 96.0% macro-averaged accuracy across these NMPs, with 100% precision and 89.0% recall. Conclusions: Irregular NMPs may be characterized using three morphometric descriptors, such as circularity, roundness, and perimeter-to-area ratio. The three-descriptor combination has highly accurate discrimination from spherical and fibrous NMPs. Full article

Microplastic (MP) and nanoplastic (NP) pollution has emerged as a pervasive and still insufficiently quantified pressure on terrestrial ecosystems, yet its consequences for wild herbivores remain incompletely understood. As key links between primary producers and higher trophic levels, wild herbivores occupy a critical ecological position and may serve both as exposed receptors and as biological vectors of plastic contamination. This manuscript presents a narrative review that synthesizes recent advances in understanding the physiological, behavioural, and ecological implications of MP and/or NP exposure in free-ranging herbivorous mammals, integrating evidence from field surveys, experimental studies, ecological modelling, and supportive mechanistic findings from livestock and experimental mammalian systems. Available evidence indicates that MPs and NPs are consistently detected in wild herbivores from both human-modified and protected landscapes, demonstrating widespread terrestrial exposure. Reported biological effects include oxidative stress, digestive dysfunction, inflammatory and immune responses, altered gut microbial communities, impaired nutrient assimilation, and organ-level damage, although much of the mechanistic evidence derives from controlled laboratory or livestock-based studies rather than direct wildlife investigations. Behavioural responses remain comparatively underexplored, particularly in large-bodied herbivores, with limited evidence for altered foraging, habitat use, and stress-related behaviours. At the ecosystem level, emerging studies suggest that herbivores may contribute to the landscape-scale redistribution of MPs and NPs through movement and faecal deposition, with potential downstream effects on soil processes, nutrient cycling, and plant–herbivore interactions. However, the current evidence base is constrained by major methodological and conceptual limitations, including the lack of standardized detection and reporting protocols, limited ecological realism in exposure studies, taxonomic and geographic biases, and poor resolution of long-term population-level and food-web consequences. Overall, the available literature indicates that MP and NP pollution represent a multifaceted and emerging risk to wild herbivores and the ecosystems they inhabit. Future research should prioritize standardized contamination-controlled monitoring, non-invasive faecal surveillance, ecologically realistic chronic exposure studies, and integrated conservation frameworks that recognize wild herbivores as sentinel species for terrestrial plastic pollution. Full article

Currently, there are no data and studies from Lake Vaya, Burgas city, on the status and quantity of microplastic (MP) particles in fish. This is the first study on the abundance, morphotype, size, polymer type, and color of MP in Gambusia affinis and Liza saliens from the lake. In this study, we also investigated the distribution of MPs in different parts of the fish. Within each morphological group of MPs, three size classes were recognized: 25–100 µm, 100–200 µm, and 200–500 µm. Microplastics were found in all studied fish tissues except for caviar, but in different proportions of pellets, fibers, and fragments. In our study, fibers were the most isolated, followed by irregularly shaped MPs—fragments. Two types of polymers were found—PET and PA. There are currently no studies in Lake Vaya that assess the risk of ingestion of microplastics for fish health and human health. Research shows that almost all aquatic environments worldwide are at risk of MP contamination. Laboratory and field studies highlighted that fish are particularly susceptible to MP ingestion, although freshwater species have been studied less than marine ones. The results of our study suggest that consumption of fish from Lake Vaya may expose citizens to risk. Full article

Microplastics (MPs) and metals frequently co-occur in aquatic environments, yet their combined effects on gut health and antimicrobial resistance in fish remain poorly understood. This study investigated the chronic effects of polyethylene (PE) and polystyrene (PS) microplastics, alone or combined with copper (Cu), on intestinal integrity, the gut-associated Gram-negative cultivable fraction, and phenotypic antimicrobial resistance in adult zebrafish (Danio rerio). Fish were exposed for 21 days to MPs (1 mg/L), Cu (25 µg/L), or their combinations. Histopathological analysis revealed that Cu-containing treatments induced more severe intestinal alterations, including edema, villus degeneration, and necrosis, whereas MPs-only exposures produced milder and heterogeneous responses. The composition of the Gram-negative cultivable fraction varied among treatments, with Cu, particularly in combination with MPs, associated with a broader occurrence of opportunistic and potentially pathogenic taxa. Antimicrobial susceptibility testing showed a high prevalence of multidrug resistance across treatments, with broader resistance spectra observed in Cu-containing exposures, consistent with metal-driven co-selection. In contrast, MPs alone did not systematically increase resistance and, for some antibiotics, showed resistance levels comparable to or lower than controls. Integrated multivariate analyses indicated that intestinal pathology and antimicrobial resistance co-varied along gradients of overall stress severity and stressor type, with Cu acting as the dominant driver and MPs exerting a modulatory, context-dependent influence. Overall, these findings highlight the importance of integrated assessments of gut pathology, microbial composition, and antimicrobial resistance to better understand the ecological and One Health implications of combined microplastic–metal exposure in aquatic systems. Full article

Microplastics (MPs) are emerging pollutants of global concern, posing significant ecological and human health risks. They are frequently detected in stormwater systems, with urban runoff serving as a major transport pathway into the environment. Green stormwater infrastructure, particularly bioretention systems (BRSs), offers a promising approach to mitigate these risks by filtering and retaining various contaminants. However, the occurrence of MPs in BRSs and their capacity to retain these pollutants remain largely unexplored in the literature, despite being critical for stormwater management and water quality protection. Therefore, this study attempted to examine the occurrence, vertical distribution, and trapping of MPs within a field-installed BRS, potentially emphasizing their role in reducing microplastic (MP) transport. Therefore, field samples were collected at depths of 2, 12, and 24 inches below the surface and processed in the laboratory for MP detection and quantification. The results revealed an average concentration of 1095 particles per kg of dried sediment, with fragments (microplastics shape) accounting for 78.54% of the total MPs. Although no clear vertical distribution pattern was observed, the initial findings showed that MPs were mostly retained at 24 inches, potentially indicating their transport through the media and the retention capacity of a BRS (surface and middle layer) in capturing microplastics from stormwater environments. However, there is no direct evidence to explain the mechanisms driving the observed concentrations at greater depths. The preliminary findings of this study highlight that the concentrations of different sizes of MPs can vary with soil depth in bioretention media. Integrating a BRS into urban stormwater infrastructure likely provides the dual benefits of improved stormwater management and reduced plastic pollution. This study underscores the importance of optimizing bioretention design and media composition to enhance MP trapping from stormwater. Full article

The accurate quantification of microplastics (MPs) in aquatic environments remains challenging due to the heterogeneous distribution of MPs in different environments, making representative sampling difficult, as well as methodological variabilities in sampling, sample processing, and detection. This study examined measurement fluctuations for MP analysis across four distinct water matrices: wastewater treatment plant (WWTP) effluent, tap water (TW), combined sewer overflow (CSO), and surface water (SW). Two sampling strategies were compared: grab sampling (0.5 L, n = 5) and large-volume filtration using a particle sampling unit (PSU; 100 L, 10 µm mesh, subsampled). Samples were processed through oxidative digestion, stained with fluorescent dye, and analyzed via fluorescence microscopy with automated particle counting. Recovery experiments using polyamide (PA) reference particles (357 ± 60 µm) were conducted to assess method accuracy. PSU sampling demonstrated higher precision (mean R.S.D. 41 ± 17%) compared to grab sampling (mean R.S.D. 64 ± 19%), despite additional variability introduced by subsampling. Recovery rates reached 93 ± 7% for grab samples and 88 ± 23% for PSU samples with complete filter analysis. Statistical modeling revealed that achieving a ±25% margin of error (95% CI) required 21 PSU samples versus 51 grab samples. The quadratic relationship between the margin of error and required sample size underscores the importance of methodological optimization for cost-effective monitoring. These findings provide practical guidance for designing MP monitoring campaigns and demonstrate that fluorescent labeling combined with large-volume sampling offers a reliable approach for MP quantification in diverse aquatic environments. Full article

Microplastics are emerging environmental contaminants capable of crossing epithelial barriers and circulating systemically, potentially affecting organisms, including humans. This study investigated the hematological and biochemical effects of sub-chronic oral exposure to polystyrene microplastics (PS-MPs) in male Swiss albino mice. Animals received 1 μm PS-MPs in drinking water at 0.01 mg/day for four weeks, followed by a two-week recovery period. Blood samples were collected weekly for hematological and biochemical analysis. PS-MP exposure resulted in an increased number of certain immunocytes after the first week of treatment. The highest values compared with the control group were observed in Week 2, reaching 18.5 ± 4.61 vs. 7.2 ± 1.14; 10.9 ± 2.58 vs. 5.1 ± 1.20; and 5.8 ± 2.35 vs. 2.2 ± 0.69 × 10⁹ cells/L for white blood cells, lymphocytes, and granulocytes, respectively (p < 0.001). A significant increase in platelet count was also observed, becoming evident by Week 6 (725.8 ± 307.96 vs. 470.1 ± 121.87 × 10⁹ cells/L, p < 0.05). The elevated alanine aminotransferase and aspartate aminotransferase activities observed after PS-MP exposure were potentially associated with hepatic pathology, erythrocyte damage, and inflammatory responses. No significant recovery was observed during the period after exposure. These findings demonstrate that sub-chronic oral PS-MP exposure induces inflammatory responses and may disrupt organ function. Full article

Understanding the toxicity of micro- and nanoplastics (MNPs) in aquatic systems, combined with temperature, is essential in order to assess ecological hazard in a multi-stressor environment. This study investigated the biological responses of marine and freshwater organisms of different trophic levels (including primary producers, decomposers, and consumers) exposed to polystyrene (PS) MNPs, tested at varying concentrations and particle sizes under two temperature conditions (control and +2 °C). Overall, differences were observed between trophic levels: Paracentrotus lividus larvae were more sensitive to higher temperatures, Daphnia magna exhibited a non-linear pattern, and microalgae have generally shown low sensitivity to both MNPs and high temperatures. However, the MNPs’ responses were not generally concentration-dependent, with the exception of Dunaliella tertiolecta. The effects recorded at increased temperature generally varied among species, indicating that even a moderate increase in temperature can modulate responses in different organisms. In the marine system, hazard levels increased with temperature, whereas in freshwater, they were higher but temperature-independent. These results highlight the importance of integrated assessment approaches to accurately evaluate the ecological hazard associated with MNPs pollution in the context of climate change. Full article

Microplastic (MP) pollution has emerged as a significant environmental crisis across the Arabian Gulf, driven by rapid urbanization, industrialization, and infrastructure challenges in waste management. Studies indicate that MPs are ubiquitous in nature and are present in different environmental compartments, including coastal waters, sediments, marine biota, and the atmosphere. The region is characterized by high salinity, high UV index, and frequent dust storms that can affect the physical and chemical behavior of plastic debris. A consistent finding across regional studies highlights the fibrous polyethylene (PE) and polypropylene (PP) polymer types as dominant microplastic particles. This prevalence of fibrous MPs highlights the role of secondary microplastics that are derived from the fragmentation of larger plastic items and textile-derived materials as a major contaminant source. Ecological impacts are increasingly observed, with studies reporting MP ingestion in commercially important fish species and the potential for biomagnification into the human food web. However, there exist key knowledge gaps regarding the long-term toxicological impacts on human health. This review synthesizes existing data to improve the understanding of microplastic distribution in Qatar and the Arabian Gulf while highlighting the need for standardized monitoring approaches and appropriate waste management strategies. Full article

The growing accumulation of microplastics in marine environments demands fast and accurate analytical methods for polymer identification. This study presents a new canonical spectral transformation (CST) strategy designed to extract the most relevant information of Raman spectra and enhance the performance of artificial intelligence (AI) models in the classification of microplastics. Using the Marine Plastic Database (MPDB) as the source of Raman spectra, five supervised models—k-Nearest Neighbor (KNN), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Multilayer Perceptron (MLP), and a one-dimensional Convolutional Neural Network (CNN-1D)—were trained and evaluated under both typical (conventional methodology) and CST workflows using 500 noisy samples per category. The CST consists of representing a Raman spectra in a vector where only the magnitude peaks of the most relevant frequency bands of the spectra are retained and the remaining values are null. This CST minimizes the inclusion of non-target data reaching the AI models. All models achieved higher accuracy with CST, where CNN-1D achieved the most significant performance, increasing accuracy to 0.90. In addition, CNN-1D identified Polystyrene (PS) and Poly(methyl methacrylate) (PMMA) with a score of 100% and 99%, respectively. The results demonstrate that CST effectively enhances spectral feature extraction and can be generalized to other spectroscopic techniques, providing a scalable framework for AI-assisted microplastic identification in seawater samples. Full article

The presence of microplastics (<5 mm) has become a major threat to marine ecosystems and the organisms inhabiting them. This issue affects a wide range of animals, including commercially important marine fish, whose ingestion of microplastics can cause mechanical and metabolic damage. This study aimed to characterize the main types of microplastic-like particles ingested by Centropomus viridis, Cynoscion othonopterus, Pomadasys macracanthus, Diapterus peruvianus, Lutjanus colorado, and Scomberomorus sierra, important commercial fish species in northwestern Mexico. Four sampling events were conducted over an annual cycle (November to August) in the lagoon and insular systems of Navachiste and Ohuira, Sinaloa, Mexico (RAMSAR sites 1826 and 2025). A total of 556 individuals were captured, and their stomach contents were analyzed using stereoscopic microscopy. Systematic sediment sampling was also performed at each capture site (El Coloradito, El Caracol, El Huitussi, El Aparecido, El Cerro Cabezón, Topolobampo, El Cerro Partido, and El Tortugo) by examining the upper 30 cm of sediment to ensure representativeness of the particle inventory. Four of the six analyzed species (C. viridis, C. othonopterus, P. macracanthus, and D. peruvianus) contained microplastic-like particles (MP-p), totaling 163 items, with an average ingestion rate of 0.29 items individual⁻¹. The omnivorous species D. peruvianus showed the highest ingestion (0.52 items individual⁻¹; 0.0029 items g⁻¹ wet weight). Five categories of MP-p were distinguished based on morphology and fluorescence; however, their polymeric identity cannot be confirmed without spectroscopic analyses. Sediment results showed that most microplastic-like fragments occurred at site 2025 during autumn, spring, and summer, while levels at site 1826 did not differ significantly. This study provides the first evidence of microplastic contamination in these fish species and in this region of northwestern Mexico. Full article

The study of river basins is key to understanding the dynamics of microplastic (MPs) generation, transport, and accumulation in regions where various productive activities converge and waste management is limited. The objective of this study was to characterize economic activities in the Tecolutla River basin, Mexico, to identify risk factors associated with MPs generation and release throughout the production chain. A descriptive applied research study was conducted using a structured questionnaire administered to 19 economic units distributed across seven municipalities in the Tecolutla River basin, Veracruz, Mexico. The instrument allowed for the evaluation of the use of plastic materials in inputs, production processes, final products, and waste management practices. Among the economic units analyzed (n = 19), 94.7% reported the use of polymeric materials, with a predominance of thermoplastics such as polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polypropylene (PP), which have a high potential for secondary fragmentation. Within the tertiary sector, accommodation and food preparation services account for the highest proportion of units with limited separation and recycling practices. Activities in the secondary sector, especially the textile and construction industries, showed a high potential for releasing this pollutant due to the use of synthetic fibers, composite materials, and the absence of retention systems. The results provide a basis for the design of mitigation strategies targeting priority productive sectors at the watershed scale. Full article

Microplastic (MP) contamination in freshwater systems has emerged as a growing environmental concern. This study investigated the occurrence and seasonal variability of MPs in surface water, the water column, and sediments at selected sites in Lake Alhajuela, Panama. Lake Alhajuela is an artificial reservoir that supplies water to the Panama Canal lock system and to the cities of Panama and Colón, serving more than 50% of the country’s population. MPs were isolated using two digestion protocols followed by density separation, and fragments and films larger than 1 mm were chemically characterized using FTIR–ATR spectroscopy. Mean MP concentrations were 759 ± 536 MPs L⁻¹ in surface water, 328 ± 140 MPs L⁻¹ in the water column, and 109 ± 87 MPs g⁻¹ in sediments. Statistical analyses revealed no significant differences among sampling sites; however, significant seasonal differences were observed (p < 0.01). Smaller MPs (63–249 µm) were more abundant compared to larger MPs (>250 µm). Fragments and fibers were the most predominant type of MP reported. Our results confirm the presence of MPs in the surface and water column, as well as sediments of the Alhajuela Lake. Further studies are needed to elucidate the fate, sources, transport, and distribution of MPs across Lago Alhajuela as well as to assess the lake’s potential contribution of MPs to Gatun Lake and the Panama Canal system. Full article

Terrestrial environments function as major sinks and dynamic sources of microplastics. Land use strongly influences inputs, accumulation, and transport pathways of these contaminants in the environment. Despite the extensive literature, few reviews have compared contamination levels and the potential impacting factors across land uses. To fill this gap, this review synthesizes current knowledge on the origins, occurrence, pathways, and ecological effects of microplastics across diverse land uses. The review revealed multiple interconnected pathways that drive microplastic contamination in terrestrial systems. Abundances are consistently higher in intensively managed croplands, urban areas and industrial vicinities. However, their detection in remote environments underscores the critical role of diffuse inputs and long-range atmospheric transport. Vertically, microplastics are enriched in topsoils, and their concentrations declines with depth. Horizontally, concentration declines with increasing distance from major hotspots like agricultural fields, industrial facilities, and road networks. Ecologically, microplastics alter soil physical properties, modify chemical conditions, and shift microbial community composition and enzyme activities. Furthermore, they stress soil fauna and plants through ingestion, toxicity, and physical blockage, with impacts contingent on polymer type, particle morphology, and concentration. Collectively, this review reveals consistent spatial patterns and widespread adverse ecological impacts, highlighting the clear need for integrated management strategies to mitigate terrestrial microplastic pollution. Full article

Microplastics represent an emerging threat to aquatic ecosystems, human health, and coastal aesthetics, with increasing concern about their accumulation on beaches due to ocean currents, wave action, and accidental spills. Despite their environmental impact, current methods for detecting and quantifying microplastics remain largely manual, time-consuming, and spatially limited. In this study, we propose a deep learning-based approach for the semantic segmentation of microplastics on sandy beaches, enabling pixel-level localization of small particles under real-world conditions. Twelve segmentation models were evaluated, including U-Net and its variants (Attention U-Net, ResUNet), as well as state-of-the-art architectures such as LinkNet, PAN, PSPNet, and YOLOv11 with segmentation heads. Models were trained and tested on augmented data patches, and their performance was assessed using Intersection over Union (IoU) and Dice coefficient metrics. LinkNet achieved the best performance with a Dice coefficient of 80% and an IoU of 72.6% on the test set, showing superior capability in segmenting microplastics even in the presence of visual clutter such as debris or sand variation. Qualitative results support the quantitative findings, highlighting the robustness of the model in complex scenes. Full article