Waste Deposits Research Articles

YOLOv8-C2f-Faster-EMA: An Improved Underwater Trash Detection Model Based on YOLOv8.

Anthropogenic waste deposition in aquatic environments precipitates a decline in water quality, engendering pollution that adversely impacts human health, ecological integrity, and economic endeavors. The evolution of underwater robotic technologies heralds a new era in the timely identification and extraction of submerged litter, offering a proactive measure against the scourge of water pollution. This study introduces a refined YOLOv8-based algorithm tailored for the enhanced detection of small-scale underwater debris, aiming to mitigate the prevalent challenges of high miss and false detection rates in aquatic settings. The research presents the YOLOv8-C2f-Faster-EMA algorithm, which optimizes the backbone, neck layer, and C2f module for underwater characteristics and incorporates an effective attention mechanism. This algorithm improves the accuracy of underwater litter detection while simplifying the computational model. Empirical evidence underscores the superiority of this method over the conventional YOLOv8n framework, manifesting in a significant uplift in detection performance. Notably, the proposed method realized a 6.7% increase in precision (P), a 4.1% surge in recall (R), and a 5% enhancement in mean average precision (mAP). Transcending its foundational utility in marine conservation, this methodology harbors potential for subsequent integration into remote sensing ventures. Such an adaptation could substantially enhance the precision of detection models, particularly in the realm of localized surveillance, thereby broadening the scope of its applicability and impact.

Assessment of the Thermal Properties of Gypsum Plaster with Plastic Waste Aggregates.

Building material manufacturers must support new production models that encourage the manufacture of more efficient and sustainable products. This includes thinking about savings in the use of raw materials, a contribution to the energy efficiency of buildings during their useful life, and a reduction in the generation and deposit of waste in landfills. In this research, an analysis of the thermal properties of gypsum composites added with plastic waste is carried out using the most common methods, the steady state method and the transient plane source method, and the effect of water saturation on these composites is tested. The results show an improvement in the thermal performance of the composites (values reduced with respect to the reference by 4-7%), despite their heterogeneity, as well as a variation in the measurements carried out, depending on the method used for the measurements (variation up to 10%). It is also found that the degree of humidity negatively affects the thermal conductivity coefficient but, on the contrary, this coefficient is not altered in the composites with plastic waste, due to their lower hygroscopicity. Therefore, it is considered that the proposed eco-plasters are a good alternative to traditional plasters, with which to contribute to the achievement of the objectives of the current European directives on waste and circular economy.

Contents of potentially toxic elements in sediments and waters of the Meža river and its tributaries draining mine waste deposits

The results of the monitoring of the contents of potentially toxic elements (PTE) in sediments (2013, 2017, 2020) and waters (2017, 2020) of the Meža River and its tributaries, which drain mining waste deposits, are presented. A total of 13 sample sites were established in a sample scheme that enables long-term observation of the impact of mining waste deposits. In the sediments, the content of PTE, especially Pb, Zn, Cd, Mo and As, is greatly elevated and fluctuates with time. The study area is affected by more than 300 years of mining and ore processing industry. The differences in the contents in various years are most pronounced in the Meža River tributaries, which drain the mining waste dumps. Hydrological conditions have a significant influence on the contents in sediments, as PTE content increases with higher water level and higher water flow. Water erosion of mining waste dumps has a significant impact on the discharge of contaminated material into watercourses. In contrast, in the upper part of the Meža River, we did not observe strong influence of higher water level on the content of PTE in the sediments. Fluctuations in the content between individual years and fluctuations between various hydrological conditions are higher again in the middle part of the the Meža river, downstream from Žerjav. The presented results demonstrate that the contents of Pb, Zn, Cd, Mo and As in the sediments of the Meža River and its tributaries are very high and that they by far exceed the legislative critical value for the soil. PTE contents in the surface water are elevated in some locations and do not change significantly over time. The local concentrations of Pb, Cd and Zn exceed the legislative guidelines. We estimate that the dynamics of the sediment load in the Meža River along the towns of Črna na Koroškem, Žerjav and Mežica is very complex. In addition to mining waste deposits, the content of PTE in sediments and waters is also affected by scattered sources in the environment, such as contaminated soil and floodplains and their varying degrees of pollution, as the environment has been burdened by long-term mining, ore processing and smelting activities. Current industrial activity may also have an additional environmental impact.

Towards Sustainable Modes for Remote Monitoring in Waste Management: A Study of Marginalized Urban Areas in Romania

Implementing circular and carbon-neutral waste management practices is essential for promoting environmental sustainability and public health. This is particularly critical in marginalized areas, where effective waste management strategies play a pivotal role in addressing environmental challenges, promoting community well-being, and fostering sustainable development. The article will explore waste management in marginalized urban areas in an integrated manner, exploring key European research domains: waste management, housing in informal settlements, and spatial information. We examined 37 Local Development Strategies (LDSs) for marginalized urban areas (MUAs) in Romania to determine whether they incorporate waste management measures. In addition, we used QGIS along with imagery accessible on the European Space Agency’s platform. This supplies Copernicus Sentinel-2 satellite data. We referred to a specific urban area, namely the Municipality of Turda, selected from the endorsed LDS, where the illegal landfills are present. Based on the data presented in the LDS and confirmed with the in situ verification or remotely using street view platforms, we have determined that the identified areas indeed contain illegal waste deposits. To validate these findings, the methodology employed, along with observations and results from the Turda study area, can be extended to other territories and marginalized urban areas.

Geometry, Extent, and Chemistry of Fermentative Hot Spots in Municipal Waste Souk Sebt Landfill, Ouled Nemma, Beni Mellal, Morocco

The presence of fermentative hotspots in municipal waste dumps has been reported for several decades, but no study has focused on their size and shape. The uncontrolled landfill of Soub Sekt, covering an area of about 8 hectares in the Tadla plain in Morocco, is the source of a permanent pollution plume in the groundwater, detected by self-potential (SP) measurements. The study aims to detect and characterize these hotspots as well as the leachates that form within them. These hotspots are typically circular and smaller than 3 m in size, and they are concentrated within recent waste deposits. Intense electron transfer activities, particularly during redox reactions leading to metal solubilization, result in very low SP values (down to −60 mV), facilitating their detection. Several successive field campaigns suggest that they are active for 2–3 weeks. Due to the low permeability of the soils, highly mineralized leachates (average Electrical Conductivity 45 mS cm−1) rich in organic ions accumulate on the soil surface at the base of the waste windrows. There, they evolve by concentration due to evaporation and oxidation due to slow diffusion of atmospheric O2. Despite the small size of the hotspots generating the leachates, the accumulation of leachates in ponds and the low soil permeability limits the percolation rate, resulting in moderate but permanent groundwater pollution.

Efforts to Reduce Plastic Waste Through Making Environmentally Friendly Shopping Green Bags at the Berkah Balai Baru Waste Bank

The Berkah Balai Baru Waste Bank was established on 20 November 2021. The waste management activity running at this Waste Bank is the waste deposit activity. Another program that has yet to be implemented is empowering waste bank officers and customers to make green bags to reduce plastic waste. Waste bank officers still need to gain the skills to create green bags. This service activity aims to increase people's insight into the dangers of plastic waste for environmental health and improve people's skills in making green bags. The educational methods used are persuasive communication, lectures, and two-way dialogue. During training, the method used is the product creation and practice training method; during activity mentoring, monitoring and evaluation of activities were carried out. This community service activity targets officers and customers of the Berkah Balai Baru waste bank. The results of the community service activities were that after carrying out the pre and post-test and comparing the score results, it was found that there was an increase in participants' knowledge by 29.9%, and there was participant enthusiasm, as shown by the feedback during the discussion session. Waste bank officers have been able to make shopping bags that can be used when shopping and can be a business opportunity for the Berkah Balai Baru Waste Bank. With this activity, waste bank officers have contributed to reducing plastic waste in the environment.

Biomassa e demanda hídrica do capim mombaça em solo afetado pelo rompimento da Barragem do Fundão

ABSTRACT The collapse of the Fundão Dam in Mariana, MG, in 2015 introduced the challenge of using Technosol, a soil type formed by deposition of iron mining waste along the Doce River banks, for agricultural purposes. This study aimed to determine the optimal water depth for enhancing production of tropical forage, Megathyrsus maximus cv. Mombasa, when grown on iron ore tailings. Additionally, it sought to establish a crop coefficient applicable to the edaphoclimatic conditions of Viçosa, MG, Brazil. The experiment was conducted throughout the summer, fall, and winter of 2022, employing 21 drainage lysimeters. A completely randomized experimental design was adopted, featuring six treatment groups (plants in Technosol receiving water depths ranging from 20 to 120% of the crop’s evapotranspiration, as derived from the control treatment), along with a control group (plants in Latosol with a depth of 100%), each with three repetitions. Our findings showed that irrigation must replace 40% of the crop evapotranspiration. Moreover, cultivating in Technosol resulted in a reduction of productive capacity by 37.39% during the summer/fall and fall seasons. For Mombasa grass grown in Oxisol, crop coefficients of 1.2 during the summer and 1.5 during the fall and winter are advised.

Ecologization of Waste from the Steel Industry in Civil Engineering Works

The massive industrialization of the last century has come with the drawback of creating large waste deposits. Over the past century, steel mills have generated significant quantities of steel slag, deposited in heaps that occupy vast land areas. The desire to recycle steel slag arises from both ecological and economic interests. To achieve this goal in the steel industry, it was necessary to recycle steel slag (waste from the technological process of steel production) by using them as aggregates in civil constructions. In this work, the optimal option will be determined based on the mathematical modelling of the main physical-mechanical characteristics of the asphalt mixtures used in wear layers made with steel slag aggregates in comparison with classic asphalt mixtures.

Study of heavy metal in sediment of The Klagison River, Sorong City

The Klagison River is one of the rivers located in the North Sorong District to the Sorong Manoi District. The flow of the Klagison River is used by the sand mining industry to dispose of liquid waste products from mining sites. Mining activities are in the middle of the Klagison River so that it can affect the quality of river water and experience a decrease in carrying capacity due to the high level of turbidity in river water caused by sedimentation. The purpose of this research is to provide knowledge about the content of metal elements in sediments by identifying the constituent elements of the Klagison River sediments, Sorong City, West Papua. Determination of the sampling point using the purposive sampling method and the sediment collection tool using the Ekman grab. The method of analyzing the constituent elements of the sediment uses the XRF (X-Ray Fluorescence) method. Based on the research results, there are various types of metal elements contained in the sediments of the Klagison River, namely the elements Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Zr and Re where the dominant concentration of metal elements from 5 observation stations is Fe>Si>K>Cl>Al>Ca. At the 5 observation stations, the element Fe>Si>K>Cl>Al>Ca was the highest compared to the other 4 observation stations. This is because station 5 is the mouth of the Klagison River so that it becomes a place for liquid waste deposits to coalesce.

The role of women in enhancing economic standards in rural areas through the implementation of waste reform in Desa Cemagi

Cemagi Village faces challenges in its human resources sector, which are not yet prepared to compete in the tourism industry, and waste management, which is deemed highly risky. In response to waste management issues, the Cemagi Village Perbekel has initiated the establishment of the Sarwa Metu Wangi TPS3R to oversee waste management and has appointed cadres to manage waste banks in each Banjar neighborhood. To address these issues, a pilot project was launched for women's empowerment activities in Cemagi Village, specifically in Banjar Sangiangan. These service activities aim to empower women in Cemagi Village by encouraging women's groups to actively sort waste, generate additional income from the sale of segregated waste, increase public awareness of the importance of proper waste management for environmental cleanliness and public health, and support tourism village development through the application of the Sapta Pesona principles. The method of implementing these activities involves conducting waste management awareness campaigns and providing assistance in waste sorting at residents' homes. The results of these activities indicate that the community has begun to actively sort waste in accordance with guidance provided by the implementation team during assistance. This is evident from the initial condition of waste deposits at the onset of waste bank activities, which were predominantly mixed or improperly sorted. However, after providing assistance at residents' homes, the waste brought to the waste bank has begun to be properly sorted. Changes in people's waste sorting behavior serve as an indicator of the success of awareness campaigns and mentoring efforts, reflecting an increase in public awareness regarding the importance of proper waste sorting for environmental protection.

Crystallization and rheology of Na2O–CaO–Al2O3–SiO2 melt in the vitrification of technological waste

AbstractVitrification of solid technological waste is currently under investigation. For this type of waste made up of metals, minerals, and organic matters, formulation studies were carried out in the NCAS (Na2O–CaO–Al2O3–SiO2) system in order to define a vitrifying additive to treat the entire waste deposit, while maximizing the waste loading. Main challenge related to this type of waste comes from the presence of alumina in very large quantities in the glass/glass–ceramics melt, enhancing the risk of melt solidification due to a fast and massive crystallization. Melt lock‐up can potentially occur at the operating temperature envisaged for the process (1400°C) and is prohibitive because it would lead to a premature stoppage of the process. The results obtained from casting tests, rheological experiments, and thermodynamic modeling enabled to provide an accurate estimation of the risk of melt lock‐up for NCAS compositions. It was highlighted that the composition had a major influence on the temperature at which massive crystallization might occur. From all the results obtained, the maximum Al2O3 content that could be incorporated in the final material was determined to be close to 50 wt%. The composition of a vitrifying additive was also statistically designed to treat the technological waste of interest.

Analysis of the Efficiency of Landfill Gas Treatment for Power Generation in a Cogeneration System in Terms of the European Green Deal

Climate change and environmental degradation pose a threat to Europe and the world. The mechanism that will address these challenges is the European Green Deal, which envisions transforming the EU into a modern, resourceful, economical and competitive economy, aiming for zero greenhouse gas emissions. Landfill gas generated in a landfill waste deposit poses a threat to the environment and people. In this aspect, its capture, treatment and safe neutralization or use for energy purposes are important. Treatment of landfill gas, which is the fuel for gas engines in cogeneration units, is crucial for their proper operation and the quantity and quality of electricity and heat generated. The purpose of this study was to perform research to determine the hydrogen sulfide content of landfill gas and the actual efficiency of hydrogen sulfide removal from the gas using activated carbon. The tests performed constitute the basis for the reliable operation of gas engines in cogeneration installations and are dedicated mainly to the operators of these installations. Accordingly, three measurement campaigns were carried out, each with 42 measurements, the first for the “raw” gas obtained directly from the landfill, the second for the gas before entering the carbon filter and the third after its treatment. In addition, surface analysis was performed, and the elemental composition of the “fresh” molded activated carbon constituting the filter material was determined using a scanning electron microscope with an EDS system. The results showed a high elemental content of carbon in the test sample at 92.78%, while the efficiency of hydrogen sulfide removal from landfill gas by activated carbon, calculated from the measurements, was 97.05%. The obtained test results confirmed the validity of using impregnated activated carbon to remove hydrogen sulfide from landfill gas and its high adsorption efficiency, which can consequently result in reliable operation of the gas engine in the cogeneration unit and ultimately fit in with the objectives of the European Green Deal. The research results are an incentive for operators of cogeneration installations to systematically examine the quality of landfill gas and the efficiency of biogas purification devices.

An integrative model exploring normative, situational, attitudinal and self-related determinants of household food waste separation intention and habit and intention to deposit waste at disposal centres / Modelo integrador para explorar los determinantes normativos, situacionales, actitudinales y relacionados con el yo de la intención y el hábito de separar residuos alimentarios en el hogar, y de la intención de depositar

Faced with increasing waste production, authorities are seeking to encourage better household waste management and need to identify levers for change. We propose a model integrating the major determinants of pro-environmental behaviour assumed in prominent theoretical models. Based on meta-analytical evidence, we incorporated situational, normative, attitudinal and self-processes and tested this integrative model to predict intentions to perform two overlooked behaviours: food waste separation and deposit at waste disposal centres. To go beyond intention we also investigated habits to sort food waste. An online survey was administered to two samples ( Ntotal = 2,814) and data were analysed using structural equation modelling. The results showed a good fit of an integrative model ( CFIs > .917; TLIs > .910; RMSEAs < .043; SRMRs < .071). Waste management intentions and habits are directly predicted mainly by personal norms and perceived behavioural control. The latter is predicted by facilitating conditions and pro-environmental identity. Personal norms are predicted by social norms, pro-environmental identity and perceived behavioural control. Our results confirm the relevance of a model integrating situational, normative, attitudinal and self-processes to explain waste management intentions and provide a basis for the development of waste management interventions.

Soil contamination around porphyry copper mines: an example from a semi-arid climate.

Extraction and processing of disseminated metalliferous ores, porphyry copper in particular, results in significant tonnages of waste and can cause severe disturbances and contamination in natural ecosystems. This is particularly important in semi-arid climates where natural soils are often deprived of organic matter and nutrients. This study was conducted on seven sites around Sungun Copper Mine, northwest Iran. Soil texture, EC, pH, and concentrations of nutrients, organic matter, along with 16 metal and metalloids were measured in 94 soil samples. Results showed a gradient of contamination from low contamination in natural hillsides to high contamination in mine waste depositories, Waste Dump and Oxide Dump, alongside Pakhir and Sungun Rivers. Nutrient deficiency occurred in disturbed sites. The main contaminant point sources were Waste Dump, mine pit drainage, and Oxide Dump. The results of Non-metric multidimensional scaling ordination showed elevated Cd, Zn, Fe, Cu, Pb, As, Mo, Mn, Co, S concentrations, high EC, and higher sand percentage in the sites affected by mine waste and acid mine drainage. Geo-Accumulation and Potential Ecological Risk Indices indicated that Pakhir riverside, Sungun riverside, and Oxide Dump have severe to moderate levels of environmental risks. Positive correlations between certain metal elements suggest common sources and similar reaction pathways, which may contribute to their similar geochemical behaviour in transport, deposition, and interdependence. Overall, the deficiency of organic matter and nutrients along with the soil sandy texture in contaminated sites of Sungun Copper Mine are the main limiting factors in managing metal mobility and soil remediation.

Gas equilibrium membrane inlet mass spectrometry (GE-MIMS) for water at high pressure

Abstract. Gas species are widely used as natural or artificial tracers to study fluid dynamics in environmental and geological systems. The recently developed gas equilibrium membrane inlet mass spectrometry (GE-MIMS) method is most useful for accurate and autonomous on-site quantification of dissolved gases in aquatic systems. GE-MIMS works by pumping water through a gas equilibrator module containing a gas headspace, which is separated from the water by a gas-permeable membrane. The partial pressures of the gas species in the headspace equilibrate with the gas concentrations in the water according to Henry's Law and are quantified with a mass spectrometer optimized for low gas consumption (miniRUEDI or similar). However, the fragile membrane structures of the commonly used equilibrator modules break down at water pressures ≳3 bar. These modules are therefore not suitable for use in deep geological systems or other environments with high water pressures. To this end, the SysMoG® MD membrane module (Solexperts AG, Switzerland; “SOMM”) was developed to withstand water pressures of up to 100 bar. Compared to the conventionally used GE-MIMS equilibrator modules, the mechanically robust construction of the SOMM module entails slow and potentially incomplete gas–water equilibration. We tested the gas equilibration efficiency of the SOMM and developed an adapted protocol that allows correct operation of the SOMM for GE-MIMS analysis at high water pressures. This adapted SOMM GE-MIMS technique exhibits a very low gas consumption from the SOMM to maintain the gas–water equilibrium according to Henry's Law and provides the same analytical accuracy and precision as the conventional GE-MIMS technique. The analytical potential of the adapted SOMM GE-MIMS technique was demonstrated in a high-pressure fluid migration experiment in an underground rock laboratory. The new technique overcomes the pressure limitations of conventional gas equilibrators and thereby opens new opportunities for efficient and autonomous on-site quantification of dissolved gases in high-pressure environments, such as in research and monitoring of underground storage of CO2 and waste deposits or in the exploration of natural resources.

First-Year Mortality of Four Early-Successional Species on Severely Degraded Sites in Eastern Canada as Influenced by a Factorial of Site Preparation Treatments

Barren, severely disturbed sites lacking soil, such as mine sites and waste deposit sites, present severe challenges to ecological service restoration because of high temperatures, solar radiation, and wind speeds; extreme temperature changes; and low soil moisture and nutrient availability. An ecological restoration experiment using three site preparation treatments was conducted. Straw (S), Meri-Crusher (MC), and coarse woody debris (CWD) were assessed in a site, no site preparation 2 × 2 × 2 factorial, including a control treatment, on sites barren for 25 years. In addition, four early-successional species: white birch (WB, Betula papyrifera Marsh), gray birch (GB, Betula populifolia Marsh), green alder (GA, Alnus viridis Vill. ssp. crispa Ait) and speckled alder (SA, Alnus incana L. ssp. rugosa Du Roi), were examined for mortality. Mortality was measured after three time periods, summer-related 2021, winter-related, and frost heave mortality (spring 2022). Summer-related mortality was predominantly influenced by S treatments (reduced mortality) and their interactions. Straw’s ability to retain moisture strongly suggests it mitigated summer-related drought mortality. S interactions were not rank changes but magnitude effects. The species × straw interaction showed that SA had the greatest magnitude difference, with 25% and 3.6% summer-related mortality for NS and S treatments, respectively. SA, a hydrophilic species, accounted for nearly half the total summer-related mortality, and there were strong species effects and species interactions. The full combination of site preparation treatments had the lowest summer-related mortality, at 1%. Winter-related mortality only affected 1.9% of the total sample size, and there were no species effects or interactions, but contrary to other results, S was the leading cause of mortality due to fungal presence found on expired seedlings. For frost heave mortality, it was clear that the S treatment was effective, with 1.2% and 20.7% overall mortality for S and NS, respectively. MC alone had the greatest negative effect, with 46.9% frost heave mortality; however, when interacting with S or CWD, the mortality decreased substantially. Frost heave had no species interactions and only a species effect, with SA having the greatest mortality. Over the first full year, MC alone and control had the greatest mortality, with 60% and 38%, respectively, after one year. Overall, one-year mortality showed S reduced mortality by 27% and CWD by 19%, while MC increased mortality by approximately 4%. When treatments were combined in any way, mortality dropped significantly, showing an additive effect, with the three-combination treatment resulting in the lowest one-year mortality, of only 3.1%. Straw provided the strongest effect, both as an effective barrier to moisture evaporation, providing up to 10% more soil moisture under dry conditions and provided an effective thermal barrier that substantially reduced the frost heave mortality. Even early-successional species such as WB, GB, GA, and SA need site preparation treatments to establish and survive the first year on long-term barren lands.

A Literature Review on the Effect of Plastic Waste Deposits on Soil Ecosystem

A Literature Review on the Effect of Plastic Waste Deposits on Soil Ecosystem

Мониторинг состояния растительности в районе разработки Тасеевского месторождения (Забайкальский край)

The article presents the results of an environmental survey conducted in the development area of the Taseyev gold deposit of the Baleysky district of the Trans-Baikal Territory. Environmental monitoring was carried out on the most vulnerable component of the natural environment in order to ensure the environmental safety of the facility during the implementation of the construction of a heap leaching complex on the basis of the technogenic waste deposit “Baleyskoy ZIF‑1” of the Trans-Baikal Territory. The current state of the vegetation cover was studied. An analysis of the flora of the technogenically disturbed territory of the Taseevskoye field was carried out. As part of the local monitoring of the gold deposit and its environs, 4 types of plant complexes were identified – forest, meadow-steppe, near-river and synanthropic. According to the results of the study, a satisfactory state of plant communities was revealed. A quantitative indicator of diversity has been established, which is more than 80 species within the boundaries of the allotment. Species listed in the Red Book of the Trans-Baikal Territory, growing in the background areas of this field, are noted. A change in the natural vegetation cover on the area of the technogenically disturbed landscape was recorded as a result of industrial work – the movement of soil masses, dumping and excavation. The territory is covered by a chaotic network of country roads that disturb the soil and soil cover. Along the roads gully erosion is developed. There is a negative impact and a decrease in the recreational ecosystem services of the Baleisky district due to the production activities of gold mining enterprises (insufficient formation of a comfortable environment for the population). The presence of synanthropic communities in the anthropogenically disturbed area with traces of household waste dumps, sewage disposal, changes in the microrelief during industrial development on the river is traced Unda. In general, despite the adverse factors affecting the vegetation, plants adapt to stressful situations, all disturbed areas are capable of self-healing.

Performance of biochemical tools as fish waste particle tracers in a dispersive marine system

As finfish aquaculture expands to more dispersive coastal environments, inputs of aquaculture-derived organic matter become more diffuse, but widespread. Significant amounts of organic material are likely to be exported beyond the near-farm area, where it may encounter sensitive habitats. Biochemical tracers of organic matter, such as stable isotopes and fatty acids may be useful tools for detecting diffuse waste deposition. We used numerical modelling of direct and resuspended farm waste deposition and empirical environmental measurements to evaluate a range of biochemical indicators (major nutrients, bulk stable isotopes, fatty acids, minor and trace elements) for their efficacy as particle tracers of fish waste around a shallow water (∼30 m) salmon farm, in a dispersive coastal farming area. We also compared their efficacy across a range of sampling approaches (in sediment trap material, sediment and Mytilus edulis as a bio-indicator). Elemental carbon, nitrogen and zinc indicators could accurately reflect predicted waste deposition close to the farm, but only terrestrial fatty acid indicators were able to reflect diffuse wastes farther afield suggesting they are more sensitive tracers of fish waste. Their performance as tracers also differed between sediment trap and sediment samples, with most performing better in sediment trap samples. Although translocated mussels showed evidence of fish waste assimilation in areas of high waste deposition, tissue concentrations of fish waste tracers correlated relatively poorly with modelled waste deposition. Our results highlight the sensitivity of terrestrial fatty acids as fish waste tracers for detecting diffuse waste deposition, and demonstrate that concentrations of a number of elements can be used for mapping acute waste deposition. Our findings can inform selection of biochemical tracers for improved monitoring and management of farm wastes in dispersive marine systems.

Investigation of microplastics and microplastic communities in selected river and lake basin soils of Thiruvananthapuram District, Kerala, India.

Riparian areas are highly dynamic bio-geophysical settings with a surge of waste deposition predominantly including land-based plastic discards. These polymer discards are destined to be the prime constitution of marine "plastisphere." The polymer fate is determined by waterbodies, where the chances of plastic retention are higher, eventually mediating the formation of microplastics (MPs) in years or decades. Such formed MPs are a potential threat to the aqua bio-regime. A systematic investigation of three waterbody basin soils (Karamana River, Killiyar, and Akkulam-Veli Lake) showed the presence of MPs in all the samples analyzed with varying sizes, shapes, colors, and compositions. MPs of the shapes flakes, fragments, filaments, sheets, foams, and fibers were observed with dimensions 0.3-4.7mm. Most of the particles were white in hue (WT), followed by colorless (CL), light yellow (L.Y), light brown (L.B), orange (OR), red (RD), and blue (BL), respectively. The polymer communities were identified as high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and nylon. The highest average MP density was identified in the basin of Killiyar (799 ± 0.09 pieces/kg) followed by Karamana River (671 ± 3.45 pieces/kg), indicating the closeness of the sampling station to the city center compared to Akkulam-Veli Lake (486 ± 58.55 pieces/kg). The majority of the sampling sites belonged to the slopy areas and came under the highly urbanized land category. A close association was observed between particle abundance and urban activity. The study foresees possible threats inflicted by MP abundance upon the area-wide hydro-biological system.