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.

This study investigates the chronology of copper (Cu) contamination and its stable isotopes within an emblematic Brazilian mangrove impacted by multiple urban and industrial Cu sources, deforestation, and eutrophication. In particular, it tests Cu isotopes as tracers of anthropogenic inputs into an anthropized watershed impacted by multiple sources. To do so, we used multi-isotopic approaches (δ65Cu, δ13C, and δ15N), elemental analyses (Al, Ca, Fe, P, Cu, C, and N), and selective and sequential extractions in a210Pb-dated sediment core. This geochemical "toolbox" allowed identifying two main stages of Cu evolution in the sediment core. In the first stage, before 1965, Cu isotope fingerprints responded to landscape changes, indicating a shift from marine to geogenic dominance due to the remobilization and erosion of terrestrial materials. In the second stage, after 1965, the sediment geochemical profile showed increased Cu total concentrations with a higher bioavailability (as reflected by sequential extraction data) accompanying changes in Cu isotope signatures towards anthropogenic values. The findings evidence that local industrial sources, possibly combined with diffuse urban sources, export Cu into downstream mangroves with a distinguishable isotope signature compared to natural values. This study demonstrates the applicability of Cu isotopes as new environmental forensic tools to trace anthropogenic sources in mangrove sediments. Incorporated into a robust geochemical toolbox that combines inorganic and organic proxies for sedimentary materials, this new tool provides a comprehensive understanding of Cu dynamics in mangrove ecosystems, shedding light on the historical and current sources of Cu.

Polycyclic aromatic hydrocarbons (PAHs) are one of the most common groups of pollutants that have toxic and carcinogenic effects. Black alder trees (Alnus glutinosa L.) have been used to remediate contaminated soils from industrial pollutants and heavy metals; however, their usefulness for PAH remediation is unclear. In this study, we examined the response of seedlings from four alder half-sib families (genetic groups sharing the same mother but different fathers) to exposure to four PAHs—phenanthrene, pyrene, naphthalene, and fluoranthene—each at three concentrations. Plant growth parameters were evaluated, and concentration of secondary metabolites and antioxidant activity were measured. The results of the morphological parameters showed that in general, higher PAH concentrations had a more negative effect on tree vitality than lower concentrations (shoot growth reduction by up to 76%). Each half-sib family also exhibited distinct responses in total phenol content (TPC) when exposed to varying concentrations of pollutants, with reductions in TPC ranging from 4 to 52% across different genetic lineages. Enzyme activity also varied between families, pollutants, and their concentrations; for example, while phenanthrene generally increased glutathione S-transferase (GST) activity in the 13–99-1K and 38–61-7K half-sib families, it unexpectedly decreased GST levels by 23% and 29% in the seedlings of the 26–133-6K and 41–65-7K families, respectively, emphasizing the nuanced and divergent enzymatic responses observed in this study. Further secondary metabolite and antioxidant activity analysis revealed distinct variations in the way PAHs impact the defense mechanism of alder seedlings from different genetic groups—prioritizing either enzymatic or non-enzymatic systems. To sum up, analyzing the varying effects of PAHs on distinct half-sib families of alders can prove advantageous in identifying the most efficient black alder genetic families for phytoremediation purposes.

International audience | In the Algerian Sahara, non-renewable groundwater resources estimated at 5 billion m3 thus constitute the indispensable support for irrigation. In the Berriane region in the north of Ghardaïa region (center of Algerian Sahara), an agricultural perimeter called Oued El Bir (300 ha in total) was officially created in 2013 downstream a wastewater treatment plant. A “frontier settlement” that proves the high value placed on this resource.As part of Massire project financed by IFAD (2018-2024), the objective of our study was to analyze the water reuse practices in this Berriane arid region, i.e. to study the importance of the institutional management of the treated wastewater reuse on the one hand. And on the other hand to show that the malfunctioning of the wastewater treatment plants can lead to many side effects such as the infiltration of raw sewage into the groundwater, illicit untreated wastewater irrigation and a slowdown in the development of the agricultural perimeter. Our research methodology is founded, firstly, on interviews with the local stakeholders (about 20 surveys with farmers and local institutions) and, secondly, on isotopic, chemical and biological water analyses that will be carried out soon to validate the hypothesis of infiltration of wastewater into the aquifer. In addition, to address the institutional opposition and issues relating to the technical sustainability of water reuse in the region, we implemented a water reuse demonstrator. The choice of location and equipment was determined in concertation with local stakeholders. The decentralized treatment process is based on a septic tank and a fixed bacterial filter (Advanced Enviro Septic) with 10 m3/day capacity. The treated wastewaters are used to irrigate a 1 ha surface of the new oasis area. As part of our study, we are investigating the sanitary and agronomic safety of this new treatment process for water reuse in the arid context.

Anthropogenic pollutants are near-ubiquitous in aquatic systems. Aquatic animals such as fishes are subject to physiological stress induced by pollution present in aquatic systems, which can translate to changes in behaviour. Key adaptive behaviours such as shoaling and schooling may be subject to change as a result of physiological or metabolic stress or neurosensory impacts of pollution. This can result in fitness and ecological impacts such as increased predation risk and reduced foraging success. Here, we conducted a systematic metanalysis of the existing literature, comprising 165 studies, on the effects of anthropogenic pollution on sociability and group cohesion in fish species. Both organic (number of studies = 92, posterior mean (PM) = -0.483, p < 0.001) and inorganic (n = 24, PM = -0.697, p < 0.05) chemical pollutants, as well as light exposure (n = 21, PM = -3.176, p < 0.01) were found to reduce sociability. These pollutants did not reduce group cohesion, indicating that effects may be masked in group settings, though fewer studies were carried out on group cohesion and this is a key area for future research. Mixtures of chemical pollutants (n = 16) were found to reduce cohesion (PM = -45.42, p < 0.01), but increase sociability (PM = 46.00, p < 0.01). Evidence was found that fish may behaviourally acclimate to two forms of pollutant, namely mixed chemical pollutants (PM = -0.693, p < 0.05) and noise exposure (n = 22, PM = -4.059, p < 0.05). While aquatic systems are often subject to pollution from multiple sources and of multiple types, very few studies investigated the effects of multiple stressors concurrently. This review identifies trends in the existing literature, and highlights areas where further research is required in order to understand the behavioural and ecological impacts of anthropogenic pollutants in aquatic systems.

Small pelagics are small fish species often schooling that mainly feed on planktonic organisms and are foraging species of larger animals. These species have experienced important declines in their wild populations during the last decades. For instance, the decrease of the European sardine (Sardina pilchardus) body condition has had a detrimental impact on its landings, leaving their commercial fishing unprofitable in some Mediterranean areas. The causes for this decline are not clearly established but seems to be mainly related to changes with planktonic communities inducing a switch in their foraging behaviour from particulate-feeding to filter-feeding. Moreover, it has been highlighted that sardines ingest plastic fibres throughout their natural spatial distribution, suggesting this additional pollution as a possible new threat affecting their populations’ health. In this study we developped an experimental setup allowing us to maintain wild fish in captive controlled conditions in order to test the possible factors affecting plastic fibres ingestion in sardines. We demonstrate that sardines ingest fibres from water, and the amount of fibres ingested is highly impacted by their feeding behaviour. Sardines feeding by filtration ingest less food but more plastic fibres (mean = 4.95 fibres / ind; SD = 3.43), compared to sardines that feed by particulate-feeding (mean = 0.6 fibres / ind; SD = 1.04). Moreover, a decrease in sardine body condition factor was detected for filter-feeding individuals, mostly linked to the lower amount of food they ingested rather than to the fibre ingestion itself. Nonetheless, higher water temperature seems to accelerate the pattern of fibre expulsion in filter-feeding sardines. Alltogether, it is suggested that plastic fibres pollution and phytoplanctonic changes under global change, might synergistically act at disturbing the health of this species in wild populations.

The behavior, and history of lead (Pb) contamination in the ecosystem of the Loire estuary was examined using elemental concentrations and Pb isotope data in water, sediment, bivalves, shrimps, and fish. In the estuary and in the surrounding coastal area, Pb concentrations in water and sediment decreased compared to concentrations determined in the 1980s, with concentrations ranging from 15.8 to 65.7 mg kg−1 in the surface sediment, 0.04–0.26 nM in the water column, and 48.0–77.9 mg kg−1 in suspended particles. Pb biomonitoring using blue mussels collected by the French Mussel Watch Program over the last 40 years showed a concentration decrease from 3.8 to 0.8 mg kg−1. A similar trend is observed in an estuarine sediment core. Changes in accompanying Pb isotope compositions strongly suggest a binary mixing process between Pb derived from terrigenous material and anthropogenic sources. Thus, environmental regulations restricting the release of lead into the environment contribute to a decrease in estuarine levels of this pollutant, which occurs on a decadal time scale.

International audience | Although coastal ecosystems are naturally submitted to temporal variations of salinity, salinization has been increasing over time threatening coastal biodiversity. Species that exploit such habitats can thus be exposed to brackish water at different life stages. However, the impacts of variations of salinity on wildlife remain poorly understood. This is particularly true for coastal amphibians, due to the strong dependency of early life stages (embryos and larvae) on aquatic environments. In order to investigate the effect of salinity during egg laying and embryonic and larval development of coastal amphibians, we used a full-factorial design to expose reproductive adults, eggs, and larvae of coastal spined toads (Bufo spinosus) to fresh (0 g.l⁻¹) or brackish water (4 g.l⁻¹). At egg laying, we evaluated parental investment in reproduction. During embryonic and larval development, we assessed effects on survival, development, and growth. We highlighted strong effects of environmental salinity on reproduction (reduced egg laying time, marginally reduced egg size, and reduced investment in reproduction). Responses to salinity were highly dependent on the developmental stages of exposure (stronger effects when individuals were exposed during embryonic development). These effects carried over when exposure occurred at egg laying or during embryonic development, highlighting the importance of the environmental conditions during early life on ontogenetic trajectories. We also highlighted partial compensation when individuals were transferred back to freshwater. Whether the magnitude of these responses can allow coastal biodiversity to overcome the observed detrimental effects of salinization remain to be assessed.