To mitigate land degradation and desertification as an environmntal issue, it is crucial to monitor land degradation intensities, identify influential factors, and implement necessary measures. This study utilized remote sensing data and logistic regression modeling to assess desertification in Larestan County. Multiple indicators were considered in this study, encompassing climate factors (such as rainfall, evapotranspiration, and aridity index), groundwater indicators (including electrical conductivity, chloride content, sodium absorption ratio, and groundwater level decline), soil indicators (such as EC, texture, and organic matter content), land use and land cover (LULC) type, and wind erosion. The logistic regression model was employed to identify the most influential factors contributing to desertification. The findings revealed different risk classes: a small low-risk class in the eastern and southern regions covering 2.4% of the total area, a moderate-risk class in the foothill-plain areas covering 38.3% of the total area. The high-risk class of desertification is mainly concentrated in the central part of the study area, adjacent to regions with moderate risk. It is characterized by relatively large patches, particularly in the southwest of the interior plains, covering approximately 1,980 hectares, which accounts for 7.9% of the total area. The concentration of high-risk desertification in specific areas highlights the urgent need for proactive measures to preserve the environmental balance and sustainability of the study area.

The present study was conducted to determine the effects of source separation training for municipal solid waste on the quality of compostable organic waste at District 8 of Karaj Municipality, Iran. This was an experimental study, the tools of which were  sampling and conducting experiments. The research data were collected using cluster sampling. To determine the chemical properties of wet waste, samples were taken from 480 households in 7 neighborhoods of District 8 of Karaj Municipality, followed by laboratory analysis. To measure the quality of compostable organic materials, first, waste from the studied households was received once without providing training and subjected to physical analysis (separation of wet and dry materials). Once again, after providing training, the waste of the studied households was collected separately, wet and dry, from the doorsteps of the homes. From the total wet waste samples taken from each neighborhood, after complete mixing, one sample was taken for chemical  analysis and transported to the laboratory. The measured parameters included total nitrate, organic carbon, electrical conductivity  (EC), pH, calcium, cadmium, copper, iron, potassium, magnesium, phosphorus and lead. A t-test was used to obtain the difference  between the physical and chemical properties of the wet waste before and after source separation training to households. Data  were analyzed using SPSS27 software. Based on the results, there was a statistically significant difference between the values of EC,  pH, cadmium, and iron at the level of 5%, as well as between the parameters of copper, potassium, magnesium, and phosphorus at  the level of 1%, in the pre- and post-training stages. The EC value in the pre-training phase was 9914 μs/cm, which decreased to  7350 μs/cm after training. Calcium levels were 19,674 and 30,898 mg/kg, potassium levels were 24,006 and 18,225 mg/kg,  phosphorus levels were 1987 and 3019 mg/kg, and the iron levels were 1804 and 466 before and after training, respectively. The concentration of magnesium in compostable organic waste increased significantly in the post-training phase compared to the pre-training phase. The findings of this study revealed the effectiveness of source separation of municipal solid waste in maintaining  the amounts of elements present in compostable organic materials at appropriate levels.

In this research, using research-descriptive methods and using data from the years 2012-2022 of meteorology and air pollution in Tabriz city, the correlation of meteorological factors and their effect on the level of air pollution in Tabriz city was investigated and zoning maps were presented. Based on the results of the research, high amounts of CO, NO2, SO2 and O3 pollutants are mostly accumulated in areas 6, 7 and 8 of Tabriz municipality, and these pollutants have different amounts in different seasons and changing the impact of meteorological factors. Investigating the role of climatic elements in the increase of air pollutants in Tabriz city shows the existence of an inverse relationship between pollutants and the increase in altitude and rainfall. The role of wind in the spring and summer seasons leads to an increase in pollutants compared to the wind direction and is almost ineffective in the winter season. As the temperature increases, the amount of carbon monoxide pollutant increases and the amount of sulfur dioxide gas decreases. In general, the examination of the temperature factor shows that the amount of air pollution increases at lower temperatures.

Macrolitter, especially macroplastics, (> 0.5 cm) negatively impact freshwater ecosystems, where they can be retained along lake shores, riverbanks, floodplains or bed sediments. Long-term and large-scale assessments of macrolitter on riverbanks and lake shores provide an understanding of litter abundance, composition, and origin in freshwater systems. Combining macrolitter quantification with hydrometeorological variables allows further study of leakage, transport, and accumulation characteristics. Several studies have explored the role of hydrometeorological factors in influencing macrolitter distribution and found that river discharge, runoff, and wind only partially explains its distribution. Other factors, such as land-use features, have not yet been thoroughly investigated. In this study, we provide a country-scale assessment of land-use influence on macrolitter abundance in freshwater systems. We analyzed the composition of the most commonly found macrolitter items (referred to as ‘top items’, n = 42,565) sampled across lake shores and riverbanks in Switzerland between April 2020 and May 2021. We explored the relationship between eleven land-use features and macrolitter abundance at survey locations (n = 143). The land-use features included buildings, city centers, public infrastructure, recreational areas, forests, marshlands, vineyards, orchards, other land, and rivers and canals. The majority of top items are significantly and positively correlated with land-use features related to urban coverage, notably roads and buildings. Over 60% of top items were found to be correlated with either roads or buildings. Notably, tobacco, food and beverage-related products, as well as packaging and sanitary products, showed strong associations with these urban land-use features. Other types of items, however, did not exhibit a relationship with land-use features, such as industry and construction-related items. Ultimately, this highlights the need to combine measures at the local and regional/national scales for effective litter reduction.

Recent research has highlighted the potential of honeybees and bee products as biological samplers for monitoring xenobiotic pollutants. However, the effectiveness of these biological samplers in tracking microplastics (MPs) has not yet been explored. This study evaluates several methods of sampling MPs, using honeybees, pollen, and a novel in-hive passive sampler named the APITrap. The collected samples were characterized using a stereomicroscopy to count and categorise MPs by morphology, colour, and type. To chemical identification, a micro-Fourier transform-infrared (FTIR) spectroscopy was employed to determine the polymer types. The study was conducted across four consecutive surveillance programmes, in five different apiaries in Denmark. Our findings indicated that APITrap demonstrated better reproducibility, with a lower variation in results of 39%, compared to 111% for honeybee samples and 97% for pollen samples. Furthermore, the use of APITrap has no negative impact on bees and can be easily applied in successive samplings. The average number of MPs detected in the four monitoring studies ranged from 39 to 67 in the APITrap, 6 to 9 in honeybee samples, and 6 to 11 in pollen samples. Fibres were the most frequently found, accounting for an average of 91% of the total MPs detected in the APITrap, and similar values for fragments (5%) and films (4%). The MPs were predominantly coloured black, blue, green and red. Spectroscopy analysis confirmed the presence of up to five different synthetic polymers. Polyethylene terephthalate (PET) was the most common in case of fibres and similarly to polypropylene (PP), polyethylene (PE), polyacrylonitrile (PAN) and polyamide (PA) in non fibrous MPs. This study, based on citizen science and supported by beekeepers, highlights the potential of MPs to accumulate in beehives. It also shows that the APITrap provides a highly reliable and comprehensive approach for sampling in large-scale monitoring studies.

Rivers are main conduits for the delivery of plastics to the sea, while also functioning as reservoirs for plastic retention. In tropical regions, rivers are exposed to both high levels of plastic pollution and invasion of water hyacinths. This aquatic plant forms dense patches at the river surface that drift due to winds and currents. Recent work suggests that water hyacinths play a crucial role in influencing plastic transport, by efficiently trapping the majority of surface plastic within their patches. However, a comprehensive understanding of the interaction between water hyacinths and plastics is still lacking. We hypothesize that the properties relevant to plastic transport change due to their trapping in water hyacinth patches. In particular, the length scale, defined as the characteristic size of the transported material, is a key property in understanding how materials move within rivers. Here, we show that water hyacinth patches trap on average 54%–77% of all observed surface plastics at the measurement site (Saigon river, Vietnam). Both temporally and spatially, we found that plastic and water hyacinth presence co-occur. The formation of plastic-plant aggregates carries significant implications for both clean-up and monitoring purposes, as these aggregates can be detected from space and need to be jointly removed. In addition, the length scale of trapped plastics (4.0 m) was found to be forty times larger than that of open water plastics (0.1 m). The implications of this increased length scale for plastic transport dynamics are yet to be fully understood, calling for further investigation into travel distances and trajectories. The effects of plastic trapping likely extend to other key properties of plastic-plant aggregates, such as effective buoyancy and mass. Given the prevalence of plant invasion and plastic pollution in rivers worldwide, this research offers valuable insights into the complex environmental challenges faced by numerous rivers.

Microcystins (MCs) are a class of toxic secondary metabolites produced by some cyanobacteria strains that endanger aquatic and terrestrial organisms in various freshwater systems. Although patterns in MC occurrence are being recognized, divergences in the global data still hamper our ability to predict the toxicity of cyanobacterial blooms. This study aimed (i) to determine the dynamics of MCs and other cyanopeptides in a tropical reservoir, (ii) to investigate the correlation between peptides and potential cyanotoxin producers (iii) identifying the possible abiotic factors that influence the peptides. We analyzed, monthly, eight MC variants (MC-RR, -LA, -LF, -LR, -LW, -YR, [D-Asp3]-RR and [D-Asp3]-LR) and other peptides in 47 water samples collected monthly, all season long, from two sampling sites in a tropical eutrophic freshwater reservoir, in southeastern Brazil. The cyanopeptides were assessed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The biomass of potential cyanobacterial producers and water quality variables were measured. MCs were detected in both sampling sites year-round; the total MC concentration varied from 0.21 to 4.04 μg L−1, and three MC variants were identified and quantified (MC-RR, [D-Asp3]-RR, -LR). Additionally, we identified 28 compounds belonging to three other cyanopeptide classes: aeruginosin, microginin, and cyanopeptolin. As potential MC producers, Microcystis spp. and Dolichospermum circinalis were dominant during the study, representing up to 75% of the total phytoplankton. Correlational and redundancy analysis suggested positive effects of dissolved oxygen, nitrate, and total phosphorus on MC and microginins concentration, while water temperature appeared to favor aeruginosins. A comparison between our results and historical data showed a reduction in total phosphorus and cyanobacteria, suggesting increased water quality in the reservoir. However, the current MC concentrations indicate a rise in cyanobacterial toxicity over the last eight years. Moreover, our study underscores the pressing need to explore cyanopeptides other than MCs in tropical aquatic systems.

Nanoplastics (NPs) can adversely affect living organisms. However, the uptake of NPs by plants and the physiological and molecular mechanisms underlying NP-mediated plant growth remain unclear, particularly in the presence of iron minerals and humic acid (HA). In this study, we investigated NP accumulation in rice (Oryza sativa L.) and the physiological effects of exposure to polystyrene NPs (0, 20, and 100 mg L−1) in the presence of iron plaque (IP) and HA. NPs were absorbed on the root surface and entered cells, and confocal laser scanning microscopy confirmed NP uptake by the roots. NP treatments decreased root superoxide dismutase (SOD) activity (28.9–44.0%) and protein contents (31.2–38.6%). IP and HA (5 and 20 mg L−1) decreased the root protein content (20.44–58.3% and 44.2–45.2%, respectively) and increased the root lignin content (22.3–27.5% and 19.2–29.6%, respectively) under NP stress. IP inhibited the NP-induced decreasing trend of SOD activity (19.2–29.5%), while HA promoted this trend (48.7–50.3%). Transcriptomic and metabolomic analysis (Control, 100NPs, and IP-100NPs-20HA) showed that NPs inhibited arginine biosynthesis, and alanine, aspartate, and glutamate metabolism and activated phenylpropanoid biosynthesis related to lignin. The coexistence of IP and HA had positive effects on the amino acid metabolism and phenylpropanoid biosynthesis induced by NPs. Regulation of genes and metabolites involved in nitrogen metabolism and secondary metabolism significantly altered the levels of protein and lignin in rice roots. These findings provide a scientific basis for understanding the environmental risk of NPs under real environmental conditions.

It has been established from previous studies that chlorophyll-a surface concentration has been declining in the eastern English Channel. This decline has been attributed to a decrease in nutrient concentrations in the rivers. However, the decrease in river discharge could also be a cause. In our study, rivers outflows and in-situ data have been compared to time series of satellite-derived chlorophyll-a concentrations. Dynamic Linear Model has been used to extract the dynamic and seasonally adjusted trends of several environmental variables. The results showed that, for the 1998–2019 period, chlorophyll-a levels stayed significantly lower than average and satellite images revealed a coast to offshore gradient. Chlorophyll-a concentration of coastal stations appeared to be related to the declining fluxes of phosphate while offshore stations were more related to nitrate-nitrite. Therefore, we can exclude that the climate variability, through river flows alone, has a dominant effect on the decline of chlorophyll-a concentration.