Search Results (8)

This study addresses the observation of floating plastic debris in freshwater environments using an Unmanned Aerial Vehicle (UAV) multi-sensor strategy. An experimental campaign is described where an heterogeneous plastic assemblage, namely a plastic target, and a naturally occurring leaf-litter mat are observed by a UAV platform in the Lake Calore (Avellino, Southern Italy) within the framework of the “multi-layEr approaCh to detect and analyze cOastal aggregation of MAcRo-plastic littEr” (ECOMARE) Italian Ministry of Research (MUR)-funded project. Three UAV platforms, equipped with optical, multispectral, and thermal sensors, are adopted, which overpass the two targets with the objective of analyzing the sensitivity of optical radiation to plastic and the possibility of discriminating the plastic target from the natural one. Georeferenced orthomosaics are generated across the visible, multispectral (Green, Red, Red Edge, Near-Infrared—NIR), and thermal bands. Two novel indices, the Plastic Detection Index (PDI) and the Heterogeneity Plastic Index (HPI), are proposed to discriminate between the detection of plastic litter and natural targets. The experimental results highlight that plastics exhibit heterogeneous spectral and thermal responses, whereas natural debris showed more homogeneous signatures. Green and Red bands outperform NIR for plastic detection under freshwater conditions, while thermal imagery reveals distinct emissivity variations among plastic items. This outcome is mainly explained by the strong NIR absorption of water, the wetting of plastic surfaces, and the lower sensitivity of the Mavic 3′s NIR sensor under high-irradiance conditions. The integration of optical, multispectral, and thermal data demonstrate the robustness of UAV-based approaches for distinguishing anthropogenic litter from natural materials. Overall, the findings underscore the potential of UAV-mounted remote sensing as a cost-effective and scalable tool for the high-resolution monitoring of plastic pollution over inland waters. Full article

The dispersion of microplastics in the sea is an emerging and crucial environmental problem. In this preliminary study, the hydrodynamics of microplastics transferred from flooded agricultural areas to the sea was assessed. The Daniel storm in 2023 in region of Thessaly, Greece, initiated the transfer of plastic debris via the Pinios River, which subsequently discharged to the coastal basin at the south area of Thermaikos Gulf (NW Aegean Sea). Field sampling and laboratory measurements of microplastics collected at the mouth of the Pinios were conducted. The dispersion of microplastics discharged by the Pinios River is subject to the dominant wind conditions over the area, which in turn determines the water circulation in the NW Aegean Sea. Thus, a hydrodynamic model was initially applied, followed by a transport model for the study of the dispersion of the microplastics. The models were applied for SW and NE winds and indicated that the majority of microplastics with a settling velocity 0.1 m/s accumulate in areas close to the river’s mouth or lateral coastal zones; however, under the influence of SW winds, minor quantities tend to reach the east coasts of the Thermaikos Gulf, while massive quantities are transported away from the river’s mouth in case of microplastics floating on the sea’s surface. Full article

The problem of plastic and microplastic (MP, <5 mm in size) pollution has received widespread attention globally, with its widespread presence being reported in various environmental media. However, a lack of standard sampling and analysis methods is making it difficult to compare data across studies and understand the source and fate of plastics and MPs. Common sampling strategies used in studies of MP in natural waters include Manta net and pump filtering using different mesh sizes, but the impact of these sampling technologies on the final MP abundance and characteristics is not well understood. This study used common sampling devices, including a Manta trawl net, shallow-water plankton pump (SPP), deep-water plankton pump (DPP), and submersible pump with on-site filtration using 50 and 330 µm aperture size meshes, to sample MP in natural coastal water. The results showed that while Manta trawl and plankton pumps produced similar MP abundance (2.0–6.0 n/m³), the MP characterization was significantly different, with fibers being the dominant MP in plankton samples (>70%) and only 14.2% in Manta trawl samples. Submersible pump sampling using a 50 µm mesh retained a higher percentage of fibers, with a two magnitude higher abundance of MPs (357 ± 119 and 553 ± 19 n/m³ for 330 µm and 50 µm mesh, respectively) attributed to the floating debris encountered during sampling and the shallower sampling depth as well as smaller sampling volume. This study highlights the key factors that impact MP abundance and characteristics as well as the challenges to harmonizing MPs sampling methods in aquatic environments, which is also helpful for data compilation across studies. Full article

Plastic pollution has been observed in many marine environments surrounding the Iberian Peninsula, from the surface water to deeper waters, yet studies on their pathways and accumulation areas are still limited. In this study, a global ocean reanalysis model was combined with a particle-tracking Lagrangian model to provide insights into the pathways and accumulation patterns of microplastics originating in southern Portuguese coastal waters (SW Iberian). The study investigates microplastics floating on the surface as well as submerged at different water depths. Model results suggest that the North Atlantic Gyre is the main pathway for microplastics in surface and subsurface waters, transporting the microplastics southwards and eastwards towards the Mediterranean Sea and the Canary Islands. Currents flowing out of the Mediterranean Sea act as the main pathway for microplastics in deep waters, transporting the microplastics along western Iberia. An average residence time of twenty days in the coastal waters suggests that microplastics do not accumulate close to their sources due to their relatively fast transport to adjacent ocean areas. Notably, a significant proportion of microplastics leave the model domain at all depths, implying that SW Iberia may act as a source of microplastics for the adjacent areas, including the Mediterranean Sea, Morocco, the Canary Islands, Western Iberia, and the Bay of Biscay. Full article

Marine plastic debris (MPD) is a globally relevant environmental challenge, with an estimated 8 million tons of synthetic debris entering the marine environment each year. Plastic has been found in all parts of the marine environment, including the surface layers of the ocean, within the water column, in coastal waters, on the benthic layer and on beaches. While research on detecting MPD using remote sensing is increasing, most of it focuses on detecting floating debris in open waters, rather than detecting MPD on beaches. However, beaches present challenges that are unique from other parts of the marine environment. In order to better understand the spectral properties of beached MPD, we present the SWIR reflectance of weathered MPD and virgin plastics over a sandy substrate. We conducted spectral feature analysis on the different plastic groups to better understand the impact that polymers have on our ability to detect synthetic debris at sub-pixel surface covers that occur on beaches. Our results show that the minimum surface cover required to detect MPD on a sandy surface varies between 2–8% for different polymer types. Furthermore, plastic composition affects the magnitude of spectral absorption. This suggests that variation in both surface cover and polymer type will inform the efficacy of beach litter detection methods. Full article

Plastic pollution poses a significant environmental threat to the existence and health of biodiversity and the marine ecosystem. The intrusion of plastic to the food chain is a massive concern for human health. Urbanisation, population growth, and tourism have been identified as major contributors to the growing rate of plastic debris, particularly in waterbodies such as rivers, lakes, seas, and oceans. Over the past decade, many studies have focused on identifying the waterbodies near the coastal regions where a high level of accumulated plastics have been found. This research focused on using high-resolution Sentinel-2 satellite remote sensing images to detect floating plastic debris in coastal waterbodies. Accurate detection of plastic debris can help in deploying appropriate measures to reduce plastics in oceans. Two unsupervised (K-means and fuzzy c-means (FCM)) and two supervised (support vector regression (SVR) and semi-supervised fuzzy c-means (SFCM)) classification algorithms were developed to identify floating plastics. The unsupervised classification algorithms consider the remote sensing data as the sole input to develop the models, while the supervised classifications require in situ information on the presence/absence of floating plastics in selected Sentinel-2 grids for modelling. Data from Cyprus and Greece were considered to calibrate the supervised models and to estimate model efficiency. Out of available multiple bands of Sentinel-2 data, a combination of 6 bands of reflectance data (blue, green, red, red edge 2, near infrared, and short wave infrared 1) and two indices (NDVI and FDI) were selected to develop the models, as they were found to be most efficient for detecting floating plastics. The SVR-based supervised classification has an accuracy in the range of 96.9–98.4%, while that for SFCM and FCM clustering are between 35.7 and 64.3% and 69.8 and 82.2%, respectively, and for K-means, the range varies from 69.8 to 81.4%. It needs to be noted that the total number of grids with floating plastics in real-world data considered in this study is 59, which needs to be increased considerably to improve model performance. Training data from other parts of the world needs to be collected to investigate the performance of the classification algorithms at a global scale. Full article

A realistic picture of our world shows that it is heavily polluted everywhere. Coastal regions and oceans are polluted by farm fertilizer, manure runoff, sewage and industrial discharges, and large isles of waste plastic are floating around, impacting sea life. Terrestrial ecosystems are contaminated by heavy metals and organic chemicals that can be taken up by and accumulate in crop plants, and water tables are heavily contaminated by untreated industrial discharges. As deadly particulates can drift far, poor air quality has become a significant global problem and one that is not exclusive to major industrialized cities. The consequences are a dramatic impairment of our ecosystem and biodiversity and increases in degenerative or man-made diseases. In this respect, it has been demonstrated that environmental pollution impairs fertility in all mammalian species. The worst consequences are observed for females since the number of germ cells present in the ovary is fixed during fetal life, and the cells are not renewable. This means that any pollutant affecting hormonal homeostasis and/or the reproductive apparatus inevitably harms reproductive performance. This decline will have important social and economic consequences that can no longer be overlooked. Full article

Environmental sampling plays an important role in quantitative and qualitative investigation of plastic pollution. Rivers are a major source, carrying plastic litter into the oceans. Microplastic sampling in riverine and coastal environments is often a challenging task due to limited access, time taken, costs, human resources, etc. Our present study evaluated the performance of newly developed sampling devices (Albatross Mark 5 and 6 (AM-5 and AM-6)) that were suitable to collect floating and suspended microplastic samples in challenging freshwater and coastal environments (95 locations). Our observations indicated a similar magnitude of microplastic concentrations with AM-5 and AM-6 sampling compared to conventional plankton nets. The sampling duration, originally 10–60 min (by plankton net), was reduced to 3 min (AM-5 and AM-6) for sampling water volumes of approximately 10 m³. The developed AM-6 device was used to collect samples from riverine and coastal environments in Japan. The microplastic particle polymer composition (using Fourier transform infrared spectrophotometry (FT-IR)), size, and shape (microscopic images) were investigated. The observations showed a statistically significant particle size reduction from the riverine to coastal areas. The dominant polymer types detected were polyethylene (PE) and polypropylene (PP). The observations were complied with the coastal microplastic observations that were reported for previous studies in Japanese water environments. Full article