The macroplastics (MaPs) and microplastics (MiPs) polluting agricultural soils raise great concerns. Unfortunately, scientists know little about the occurrence of MaPs/MiPs in soil among different farming systems. In this study, we analyzed MaPs/MiPs in soils (0–30 cm) collected from six different farming systems (wheat-maize rotations, cotton, vegetables, permanent orchards, greenhouses with and without mulching) in Quzhou county, the North China Plain, by using fluorescence microscope and micro-Fourier transform infrared spectroscopy. The results showed that the abundance of MaPs and MiPs ranged from 0.2 to 46.8 kg ha−1, and 4.1 × 103–3.7 × 104 items kg−1, respectively. The prominent colors of the MaPs were white and black. The predominant shape, size and chemical composition of soil MiPs were fragments (45–62%), <1 mm (98–99%), and polyethylene (38–43%), respectively. MaPs were mainly detected in the 0–10 cm soil layer. MiP abundance in the 0–10 cm soil layer was significantly higher than that in the 20–30 cm soil layers among different farming systems, except for the fields with wheat-maize rotations and permanent orchards (p < 0.05). Overall, cotton fields showed the highest MaP and MiP abundance, followed by vegetable fields and orchards. Redundancy analysis revealed that tillage practices and plastic film management greatly influence the size distribution of MiPs. A strong negative correlation between large-sized plastic fractions (0.2–1 mm) and tillage frequency was tested while the years of application of plastic films and the abundance of plastic residues showed a strong positive correlation with small-sized plastic fractions (<0.2 mm). Our findings conclude that agricultural mulch films are an important source of MaPs and MiPs in agricultural soil and distributions are strongly influenced by agricultural management practices and farming systems. Further studies should take farming systems and farming practices into account, thereby exploring the potential mechanisms of plastic fragmentation and granularization in agricultural soil.

International audience | Polycyclic aromatic hydrocarbon (PAH) contamination in industrial soils poses significant environmental challenges, necessitating cost-effective bioremediation approaches like tree-based phytoremediation. However, the defence mechanisms and adaptability of trees to PAH exposure remain poorly understood, while the identification of molecular markers could help in the detection of toxicity symptoms. This study explores the molecular response of Populus canadensis to a phenanthrene (PHE) contamination gradient (from 100 to 2000 mg kg−1) using RNA-seq analysis of roots and leaves after 4 weeks of exposure. Both differentially expressed genes (DEGs) and DRomics, a dose–response tool, identified transcriptomic changes, with about 50% of deregulated genes responding significantly at a benchmark dose (i.e. minimal dose that produces a significant effect) below 400 mg PHE kg−1. The highest number of DEGs was found both at a low concentration (200 and 700 mg kg−1) and at the highest concentrations (1500–2000 mg kg−1) for both roots and leaves. Ethylene signalling genes were activated via ABA-independent pathways at low concentrations and ABA-dependent pathways at high concentrations. Across the gradient, responses to oxidative stress were triggered, including reactive oxygen species scavenging and phenylpropanoid biosynthesis, specifically at 1500–2000 mg kg−1. Additionally, PHE disrupted pathways related to plant responses to biotic stress. These findings revealed unexpected dose-dependent transcriptomic shifts, demonstrating poplar’s adaptive defence mechanisms against PHE toxicity.

Numerous reviews have consistently highlighted the shortcomings of studies evaluating the effects of microplastics (MP), with many of the issues identified in 2016 still relevant in 2024. Here, we summarize the current knowledge on MP effect testing, compare guidelines, and provide an overview of risk assessments conducted at both single species and community levels. We discuss standard test materials, MP characteristics, and mechanisms explaining effects. We have observed that the quality of MP effect studies is gradually improving, and knowledge on enhancing these studies is available. Recommendations include data rescaling and alignment for ecological risk assessment, with preference for using environmentally relevant MPs. A step-by-step protocol for creating polydisperse test materials is provided. Most risk assessments indicate that concentrations observed in ecosystems globally exceed the effect thresholds measured in the laboratory. However, using a higher-tier approach, no risks are expected for freshwater benthic communities at current MP exposure concentrations. Evidence on the mechanisms behind adverse effects is growing; however, more well-designed experiments are needed. A potential solution might involve comparing natural particles with MPs that are as similar in dimensions as possible, providing insight into the mechanisms of food dilution where volume is a critical determinant of toxicity.

Increased pharmaceutical usage has led to their widespread presence in aquatic environments, resulting in concerns regarding their potential environmental impacts. Antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs) like citalopram, are frequently detected in European surface waters. Acute laboratory studies have demonstrated that citalopram can inhibit algal growth, immobilise Daphnia magna, and may result in foot detachment (i.e. the inability to adhere to a substrate) in snails. However, research on long-term citalopram exposure is scarce, and our understanding of its effects on aquatic community- and ecosystem-level is limited. Therefore, we investigated the impact of 13-week exposure to 0.01, 0.1, 1, 10 and 100 μg/L citalopram in outdoor freshwater mesocosms, focusing on water quality variables (i.e. pH, dissolved oxygen, electrical conductivity, temperature, algal chlorophyll-a, turbidity) and the structure of aquatic communities, with a special focus on mollusc foot detachment (Lymnaea stagnalis, Planorbis sp. and the total snail population). We found that environmentally relevant citalopram concentrations did not affect water quality variables, bacterial composition, zooplankton and macroinvertebrate communities. In contrast to expectations based on literature, snail foot detachment was not observed while the tested concentrations overlapped with the reported effect concentrations. This is in line with the absence of indirect adverse effects of foot detachment, such as population changes that could be the result of an increased vulnerability to predation or the inability to feed or reproduce. Reported sublethal effects in the literature, as found in laboratory studies, do not appear to lead to population- or community-level impacts in a semi-field experiment within the concentration range tested in this study. The experimental outcomes suggest that environmentally relevant concentrations of citalopram might not pose a threat to water quality variables, bacterial composition, zooplankton and macroinvertebrate communities, and snail foot detachment.

The co-occurrence of pesticides, pharmaceuticals, and MPs has resulted in combined toxicity and high risks to ecosystems and human health. However, understanding on the interactions among co-occurring pollutants in soils remains limited. This study focused on adsorption behaviour of a pesticide mixture (chlorpyrifos (CPF), pendimethalin (PDM) and pyraclostrobin (PCS)) in three soils (sandy soil (S1), loamy soil (S2), and silt soil (S3)) to examine the absorption behaviour of pesticides in the presence of the pharmaceutical compound albendazole (ALB) and starch-based microplastics (MPs). The results showed that ALB significantly decreased (p < 0.05) the adsorption of CPF, PDM, and PCS by 29 %–41 % in S1. The adsorption of CPF (+20 %) and PCS (+101 %) in S2 were significantly enhanced but PDM (−22 %) adsorption was inhibited by ALB. ALB also significantly (p < 0.05) promoted CPF and PCS adsorption in S3 by 39 % and 120 %, respectively, but did not change PDM adsorption. In soil-MP matrices, ALB significantly reduced the adsorption of CPF (−25 %), PDM (−26 %), and PCS (−21 %) in the S1-MP matrix, but no significant change in the S2 and S3-MP matrices was observed. Moreover, MPs significantly (p < 0.05) increased the adsorption of the pesticide mixture by 120–730 %, but reduced ALB adsorption by 11–24 % in soils. Further, regardless of ALB presence, correlation analysis suggested that Kd of pesticides showed positive correlations (p < 0.01) to soil organic matter, specific surface area, and clay content in soil matrices without MP-contamination, while no significant positive correlation between Kd of pesticides and soil properties was observed in soil-MPs matrices. This study indicates that co-occurring pollutants could alter the adsorption behaviour of pesticides in soil and thereby affect their bioavailability and mobility in the soil ecosystem. Further study is urgently needed to assess the ecotoxicity of co-occurring multi-contaminants, as well as their potential transport to other environmental compartments.

To address plastic pollution in agricultural soils due to polyethylene plastic film mulch used, biodegradable film is being studied as a promising alternative material for sustainable agriculture. However, the impact of biodegradable and polyethylene microplastics on soil carbon remains unclear. The field experiment was conducted with Poly (butyleneadipate-co-terephthalate) debris (PBAT-D, 0.5–2 cm), low-density polyethylene debris (LDPE-D, 0.5–2 cm) and microplastic (LDPE-Mi, 500–1000 μm) contaminated soil (0% (control), 0.05%, 0.1%, 0.2%, 0.5%, 1% and 2% w:w) planted with soybean, to explore potential impacts on soil respiration (Rs), soil organic carbon (SOC) and carbon fractions (microbial biomass carbon (MBC), dissolved organic carbon (DOC), easily oxidizable carbon (EOC), particulate organic carbon (POC), mineral-associated organic carbon (MAOC)), and C-enzymes (β-glucosidase, β-xylosidase, cellobiohydrolase). Results showed that PBAT-D, LDPE-D and LDPE-Mi significantly inhibited Rs compared with the control during the flowering and harvesting stages (p < 0.05). SOC significantly increased in the PBAT-D treatments at both stages, and in the LDPE-Mi treatments at the harvesting stage, but decreased in the LDPE-D treatments at the flowering stage. In the PBAT-D treatments, POC increased but DOC and MAOC decreased at both stages. In the LDPE-D treatments, MBC, DOC and EOC significantly decreased but POC increased at both stages. In the LDPE-Mi treatments, MBC and DOC significantly decreased at the harvesting stage, while EOC and MAOC decreased but POC increased at the flowering stage. For C-enzymes, no significant inhibition was observed at the flowering stage, but they were significantly inhibited in all treatments at the harvesting stage. It is concluded that PBAT-D facilitates soil carbon sequestration, which may potentially alter the soil carbon pool and carbon emissions. The key significance of this study is to explore the overall effects of different forms of plastic pollution on soil carbon dynamics, and to inform future efforts to control plastic pollution in farmlands.

Agricultural use of pesticides continues to rise globally. Argentina ranks fifth in use. While pesticides help yields, they also pose risks to human health and the environment. Indoor dust can present high pesticide concentrations, raising concerns about chronic exposure in non-farming households. Studies of pesticides in indoor dust are few worldwide. This pioneering study aimed to identify and/or quantify for the first time pesticide occurrence in indoor dust from urban residences in the Pampas Region, southeast of Buenos Aires Province, Argentina. Pesticide residues in indoor dust from 48 non-agricultural homes in the Pampas plain region were analysed. Study participants completed questionnaires on household demographics, pet ownership, pesticide use, gardening, and habits like leaving shoes outside. We detected 41 out of 49 targeted pesticides, including metabolites and banned compounds. Seven of the 49 tested are dual-use compounds (i.e. pesticide & biocide or veterinary applications). The synergist piperonyl butoxide, the dual-use imidacloprid, and “agricultural only” pesticides carbaryl, glyphosate, and atrazine were detected in all dust samples. Glyphosate, 2,4-D, atrazine, imidacloprid, carbaryl, tetramethrin, and piperonyl butoxide had maximum concentrations exceeding 1, 000 μg kg−1. Complex mixtures of up to 32 residues were found per sample. Questionnaire responses revealed that most participants brought shoes inside (60 %), almost all had pets (93 %), and 51 % had used flea repellents (mainly imidacloprid and fipronil). Approximately 48 % reported pesticide use in the past year, and 19 % reported exposure via their (non-farmer) jobs, e.g., via disinfection and weeding. These findings highlight the prevalence of pesticide residues in residential settings and the need for further research on long-term exposure and risks. Improved tracking of agricultural, household, and mixed-use pesticide applications is crucial, particularly in regions heavily reliant on agriculture.

The French Mediterranean coast has a long history of anthropogenic metal contamination, yet current contamination levels remain largely unquantified. This study aims to provide a comprehensive overview of metal accumulation along the coastline by establishing natural background levels, identifying spatial contamination patterns, and assessing associated ecological risks. Major elements (Al, Fe) and trace metals (Mn, Pb, Zn, Cd, Cu) were measured in surface sediments from 74 sites and in three sediment cores using ICP-MS, while mercury (Hg) was analyzed using an AMA instrument. Natural background concentrations were determined based on the depth layers of three sediment cores that predate the year 1917. This timeframe has been recognized as the pre-industrial period by applying multivariate change point analysis. Approximately 60 % of sediment samples exhibited a Pollution Load Index (PLI) above 1, indicating significant anthropogenic enrichment across the coast. The Mean Effects Range Median Quotient (m-ERM-Q) exceeded 1 only at Cortiou and Toulon, suggesting a localized ecological risk. At Cortiou, Cd (2.85 mg/kg) and Cu (212.0 mg/kg) were between Effect Range-Low (ERL) and Effect Range-Median (ERM) thresholds, while Pb (264.0 mg/kg), Hg (6.73 mg/kg), and Zn (654.0 mg/kg) were above ERM, due to wastewater discharge. In Toulon Bay, Pb (79.34 mg/kg) and Cu (50,00 mg/kg) were between the ERL and ERM, while Hg (5.57 mg/kg) exceeded the ERM, linked with long-term naval and industrial activities. These findings demonstrate pervasive metal enrichment and ecological risks driven by different sources and highlight the urgent need for targeted mitigation strategies.

Coralligenous reefs are among the most diverse Mediterranean ecosystems, particularly in the circalittoral zone. Shaped by calcified red algae, sponges, cnidarians, and bryozoans, they create a complex three-dimensional structure providing shelter for diverse fauna. These reefs develop either on steep rocky walls or as bioherms when calcified algae are the dominant organisms. Their structure and composition vary with location, depth, substrate, and environmental conditions. Assessing the status of such a complex ecosystem poses significant challenges. Ecosystem-based quality indices (EBQI) have already been applied successfully to various coastal Mediterranean habitats. Using a similar methodology, a new index, the Coralligenous Ecosystem-Based Quality Index (Cor-EBQI), was developed to assess the ecological status of the coralligenous ecosystem. The index incorporates the main functional compartments of these reefs, with each compartment weighted according to its importance in ecosystem functioning. Suitable descriptors were then selected to define five status classes for each compartment. A confidence index was also created to estimate data quality based on criteria such as methodology and expert judgement. Data from 63 sites along the French Mediterranean coast, including the Gulf of Lions, Provence, the French Riviera, Corsica, and Monaco, were analyzed. The ecological status ranged from bad to high, influenced by environmental conditions, geomorphology, anthropogenic pressures, and management practices. The Cor-EBQI is designed to meet the objectives of both the Habitats and Marine Strategy Framework Directives of the European Union. As such, it offers a practical tool for future monitoring networks across the Mediterranean Sea.

The ratio of copper stable isotopes (65Cu/63Cu, expressed as δ65Cu) in bivalves offers a promising tool to identify coastal anthropogenic sources, yet its reliability remains uncertain. This study examines Cu isotopes in oyster samples from the chronically Cu-contaminated Arcachon Bay across three stations over a four-decade period. Cu concentrations rose significantly at nearshore stations, with a smaller increase at the offshore site. δ65Cu values increased alongside Cu levels, consistent with a binary mixing between natural and anthropogenic Cu derived from antifouling paints. This finding confirms that antifouling paints are the major local anthropogenic source of Cu and demonstrates that Cu isotopes are an effective tool for tracking these compounds in coastal environments. Further investigation of additional compartments and the integration of new isotope systems can better constrain diffuse secondary inputs—such as riverine, atmospheric, and runoff—and refine source apportionment in coastal areas, like Arcachon.