International audience | Biomonitoring of persistent pesticides in birds of prey has been carried out for decades, but few studies have investigated their relevance for the monitoring of non-persistent pesticides. Herein, we determined the contamination patterns of multiple pesticides in Montagu's harrier (Circus pygargus) chicks in an intensive farming area of southwestern France. Blood samples from 55 chicks belonging to 22 nests in 2021 were assessed for 104 compounds (herbicides, fungicides, insecticides, safeners and synergists). All chicks had at least one herbicide in their blood, and half had at least two compounds. The 28 compounds detected comprised 10 herbicides, 12 fungicides, 5 insecticides and 1 synergist. Mixtures in blood were predominantly composed of herbicides, and six chicks presented a mixture of the three pesticide classes. The most prevalent compounds were sulcotrione (96% of chicks), tebutam (44%) and chloridazon (31%), of which the latter two had been banned in France for 19 and 3 years, respectively, at the time of sampling. Most compounds are considered non-acutely toxic, but sulcotrione is potentially carcinogenic, mutagenic and reprotoxic, raising questions about the effects on the health of nestlings. Biomonitoring of multiple pesticides through Montagu's harrier chicks in agroecosystems is clearly relevant because it reflects the general pattern of agricultural pesticide use in the study area. It also raises questions about exposure pathways in chicks, and further investigations are needed to disentangle the roles of dietary routes and maternal transfer for the established pesticide contamination patterns.

The transport of floating macroplastics (>2.5 cm) can be impacted by variations in hydrometeorological forcing. Several studies have demonstrated that river discharge, wind, and tides can either accelerate or impede the downstream travel path of plastic. However, there remains a substantial gap in our understanding of the impact of river geomorphological complexity on this process. In this context, the role that river bifurcations play in driving plastic dynamics under different hydrometeorological conditions is largely unexplored. Here, we show that specific plastic item categories react differently to the transport drivers, and bifurcation areas can function both as a retention and release site of plastic litter. We found that hard polyolefin appears to be the most responsive plastic to changes in flow discharge (ρ≈0.40, p≈0.01). Absolute wind velocity magnitude does not correlate to plastic transport. We explored correlations of the various plastic items types with wind vector components in all directions. Multilayer plastics correlated highest to the wind vector component that is most effective in driving plastics from an urban area to the river (ρ≈0.57, p≈0.0001). On a monthly scale, the bifurcation area retained up to 50% of the incoming upstream plastic flux. At other times, an additional 30% was released in the same area. Our results demonstrate how bifurcations distribute different plastic items types downstream under varied hydrometeorological conditions. These yields underscore the importance of assessing floating plastic transport in specific plastic item categories and taking river geomorphological complexity into account.

Emerging pollutants, such as pharmaceuticals and microplastics have become a pressing concern due to their widespread presence and potential impacts on ecological systems. To assess the ecosystem-level effects of these pollutants within a multi-stressor context, we simulated real-world conditions by exposing a near-natural multi-trophic aquatic food web to a gradient of environmentally relevant concentrations of fluoxetine and microplastics in large mesocosms over a period of more than three months. We measured the biomass and abundance of different trophic groups, as well as ecological functions such as nutrient availability and decomposition rate. To explore the mechanisms underlying potential community and ecosystem-level effects, we also performed behavioral assays focusing on locomotion parameters as a response variable in three species: Daphnia magna (zooplankton prey), Chaoborus flavicans larvae (invertebrate pelagic predator of zooplankton) and Asellus aquaticus (benthic macroinvertebrate), using water from the mesocosms. Our mesocosm results demonstrate that presence of microplastics governs the response in phytoplankton biomass, with a weak non-monotonic dose-response relationship due to the interaction between microplastics and fluoxetine. However, exposure to fluoxetine evoked a strong non-monotonic dose-response in zooplankton abundance and microbial decomposition rate of plant material. In the behavioral assays, the locomotion of zooplankton prey D. magna showed a similar non-monotonic response primarily induced by fluoxetine. Its predator C. flavicans, however, showed a significant non-monotonic response governed by both microplastics and fluoxetine. The behavior of the decomposer A. aquaticus significantly decreased at higher fluoxetine concentrations, potentially leading to reduced decomposition rates near the sediment. Our study demonstrates that effects observed upon short-term exposure result in more pronounced ecosystem-level effects following chronic exposure.

Evidence of microplastic (MP) pollution in Antarctic terrestrial environments reinforces concerns about its potential impacts on soil, which plays a major role in ecological processes at ice-free areas. We investigated the effects of two common MP types on soil physicochemical properties and microbial responses of a marine terrace from Fildes Peninsula (King George Island, Antarctica). Soils were treated with polyethylene (PE) fragments and polyacrylonitrile (PAN) fibers at environmentally relevant doses (from 0.001% to 1% w w−1), in addition to a control treatment (0% w w−1), for 22 days in a pot incubation experiment under natural field conditions. The short-term impacts of MPs on soil physical, chemical and microbial attributes seem interrelated and were affected by both MP dose and type. The highest PAN fiber dose (0.1%) increased macro and total porosity, but decreased soil bulk density compared to control, whereas PE fragments treatments did not affect soil porosity. Soil respiration increased with increasing doses of PAN fibers reflecting impacts on physical properties. Both types of MPs increased microbial activity (fluorescein diacetate hydrolysis), decreased the cation exchange capacity but, especially PE fragments, increased Na+ saturation. The highest dose of PAN fibers and PE fragments increased total nitrogen and total organic carbon, respectively, and both decreased the soil pH. We discussed potential causes for our findings in this initial assessment and addressed the need for further research considering the complexity of environmental factors to better understand the cumulative impacts of MP pollution in Antarctic soil environments.

Nitrate leaching from agriculture can be reduced by the choice of fertilizer and a proper timing of its application. For permanent grassland grown under temperate conditions, nitrate leaching was hypothesized to be lower from dairy cattle slurry (CS) compared to synthetic fertilizer calcium ammonium nitrate (CAN), based on differences in chemical composition, consequential effects on nitrogen (N) conversion processes in soil, and resulting differences in synchronization of (nitrate) N availability and plant N uptake. We tested the hypothesis in a two-year field experiment on cut grassland on a leaching-sensitive sandy soil, fertilized each year with 320 kg ha−1 of plant-available N from either 100% top-dressed CAN or a combination of 40% from CAN and 60% from sod-injected CS, and measured effects on grass herbage yield, herbage N uptake, and nitrate concentration in pore water at 1.0 m depth. Our results show a comparable level of herbage N uptake for both treatments, allowing for a proper comparison of nitrate leaching at a similar level of plant-available N. Average nitrate concentration in pore water in the main leaching period (over winter) was after the first ‘dry’ growing season 44% lower for CS + CAN (41 mg l−1) compared to CAN only (73 mg l−1), and after the second ‘wet’ growing season 35% lower for CS + CAN (32 mg l−1) compared to CAN only (49 mg l−1). Nitrogen application increased nitrate concentration at 1.0 m depth not only in winter but also in the growing season. We conclude that for permanent grasslands in temperate regions, nitrate leaching from timely applied CS may be considerably lower than from CAN, which is different from previous assumptions.

Antibiotics are a contaminant class of worldwide concern as they are frequently detected in aquatic ecosystems. To better understand the impacts of antibiotics on aquatic ecosystems, we conducted an outdoor mesocosm experiment in which aquatic communities were exposed to different concentrations of the antibiotic sulfamethoxazole (0, 0.15, 1.5, 15 and 150 μg/L). These concentrations include mean (0.15 μg/L) and maximum detected concentrations (15 and 150 μg/L) in aquatic ecosystems worldwide. Sulfamethoxazole was applied once a week for eight consecutive weeks to 1530 L outdoor mesocosms in the Netherlands, followed by an eight-week recovery period. We evaluated phytoplankton-, bacterial- and invertebrate responses during and after sulfamethoxazole exposure and assessed impacts on organic matter decomposition. Contrary to our expectations, consistent treatment-related effects on algal and bacterial communities could not be demonstrated. In addition, sulfamethoxazole did not significantly affect zooplankton and macroinvertebrate communities. However, some effects on specific taxa were observed, with an increase in Mesostoma flatworm abundance (NOEC of <0.15 μg/L). In addition, eDNA analyses indicated negative impacts on the insects Odonata at a sulfamethoxazole concentration of 15 μg/L. Overall, environmentally relevant sulfamethoxazole concentration did not result in direct or indirect impairment of entire aquatic communities and ecological processes in our mesocosms. However, several specific macroinvertebrate taxa demonstrated significant (in)direct effects from sulfamethoxazole. Comparison of the results with the literature showed inconsistent results between studies using comparable, environmentally relevant, concentrations. Therefore, our study highlights the importance of testing the ecological impacts of pharmaceuticals (such as sulfamethoxazole) across multiple trophic levels spanning multiple aquatic communities, to fully understand its potential ecological threats.

Dez River is considered as one of the highest water rivers after Karoon River, supplying water for tens of towns and villages as well as thousands of acres of agricultural lands, several fish farming plans and industrial factories. Hence, the water quality of Dez River is one of the major concerns of the area. This study was carried out using descriptive-statistical method based on a 39 year time span statistics. A number of 394 samples were analyzed and the concentration of physical and chemical parameters including pH, TDS, SAR, total cations and anions were measured. The obtained results were examined and compared based on the statistical analyses consistent with the World Health Organization (WHO) standards.  Dez River water quality has been âPerfectâ in most cases (99.8% of the statistical periods) on the basis of TDS and average sum of them amounting to 644 mg/l; indeed only in 2% of the statistical periods the water quality has been determined as Acceptable, while most of the water quality parameters have been within the permissible range of the WHO standards.

The aim of this study was to compare the components of children's physical fitness in relation to the role of air pollution in Tehran, Iran. The research method was a causal-comparative study. To achieve the research goals, 80 students of elementary school in fourth grade (10.3 ± 0.1) in Tehran, Iran were selected through available sampling. In the research phase, the researcher referred to Tehran Quality Control System, and based on the average of pollutant indicators in the past month, two Districts of Tehran, Iran were selected; District  1 (Aghdasiyeh) as the least infectious and District 20 (Rey) as contaminated. Then, the arrangement was performed to carry out physical fitness tests. The data was collected in two days. On the first day, participants performed physical fitness tests at Negin Shahr Rey Club and on the second day at the Royal Club in Aghdasiyeh district. Data was analyzed by independent t-test. The results showed that there was a significant difference between speed and agility components in two Districts 1 and 20, while there were no significant differences between power and flexibility components. Comparison of means indicated that children in area 1 had better performance than District 20. According to the results, it is suggested that the high amount of air pollution prevent children from engaging in physical activity and consider physical education teachers to take on activities that require less energy requirements.

In the current world, various types of pollution are the result of the adverse effects of human activities. One of these types of contaminations is air pollution, originated from dust. Over the years, governments and international organizations both governmental and non-governmental have made great efforts to manage and reduce the destructive effects of sand and dust storms. However, the fact is that there is a serious gap in relation to the legal documents related to management and the reduction of destructive effects of sand and dust storms. In other words, countries that are somehow involved with this phenomenon have not implemented effective measures for the compilation and approval of binding documents for the reduction of sand and dust storms. This failure is rooted in many issues, including political, economic, social, and cultural concerns. It is also worth mentioning that among the few documents on managing and reducing the destructive effects of dust, many of them at the regional level are between just two or more countries directly affected by this phenomenon. The present article, applying an analytical-descriptive method, seeks to examine the Iranian national laws and regulations as well as international legal documents on sand and dust storms; it also outlines the existing legal vacuum and provides related practical solutions. Studies show that so far, a law that directly and specifically deals with the issue of sand and dust storms has not been approved and the international community has not succeeded in drafting and ratifying a specific document in this regard.

Physical urban growth has the most significant impact on the vegetation of surrounding areas; the assessment and analysis of these changes are essential in geography and use different mechanisms. Here, remote sensing is the main technology for assessing expansion and the rate of change of land cover. Accordingly, the present study has been conducted with the aim of evaluating the physical growth of the city of Yazd in the years 1986â2016 and its impact on the trend of urban green space changes through the use of satellite images. This is an exploratory-descriptive research and it is cognitive in terms of the objective. To achieve this objective, the data from remote sensing and geographic information systems are used. The calculation of the trend of physical growth changes indicates that the city area was 3,118.25 hectares in 1986 and it increased to 15,232.47 hectares during a 30-year period; 52 percent of the urban growth was related to the horizontal and sprawl growth of the city. Assessment of the NDVI index showed that the density of vegetation had a tangible decreasing trend so that the sum of good and excellent vegetation was equal to 2,419 hectares in 1986; in 2016, the vegetation decreased to only 1,601 hectares. The maximum decrease in vegetation exactly corresponds with the maximum physical urban growth in the northwestern and the southeastern parts of the city such that the results of the research showed about 818 hectares of vegetation and gardens became constructed lands between 1986 and 2016