The aim of the present study was to assess the risks of four different pharmaceutical active compounds (PhACs; diazepam, metformin, omeprazole and simvastatin). Acute and chronic toxicities were studied using the bacterium Aliivibrio fischeri and the microalgae Pseudokirchneriella subcapitata; while the repellency and attractiveness were assessed by avoidance tests with juvenile Cypirinus carpio using a multi-compartmented exposure system. Omeprazole was found to be an acutely toxic drug (EC₅₀: 0.015 mg/L), while the other PhACs, except simvastatin, showed some chronic toxicity. Regarding avoidance, simvastatin and omeprazole induced an escape response for 50% of the fish population at 0.032 and 0.144 mg/L, respectively; contrarily, diazepam was attractive, even at lethal concentrations, representing a dangerous trap for organisms. The toxicity of the PhACs seemed not to be directly related to their repellency; and the mode of action seems to determine the repellency or attractiveness of the chemicals. Contamination by PhACs is of concern due to the environmental disturbance they might cause, either due to their acute and chronic toxicity (at the individual level), repellency (at the ecosystem level: loss of local biodiversity) or attraction to potentially lethal levels.

Passive biomonitoring was applied in four Atlantic forest plots in southeast Brazil, affected by different levels of trace metal pollution (OP site located in Minas Gerais State and PEFI, PP and STG located in São Paulo State). Native tree species were selected as biomonitors according to their abundance in each plot and successional classification. Current trace metal concentrations in total suspended particles, leaves of non-pioneer (NPi) and pioneer (Pi) species, topsoil (0–20 cm) and litter and concentration ratios at the plant/soil interface were analyzed to verify the atmosphere-plant-soil interactions, basal concentrations, spatial variations and metal accumulation at the ecosystem level. Redundant analysis helped to identify similar characteristics of metal concentrations in PP and PEFI, which can be influenced by the high concentrations of elements related to anthropogenic inputs. Analysis of variance and multivariate statistics indicated that the trees of OP presented higher concentrations of Cr, Fe, Mn and Ni than those in the other sites. High enrichment of Cd, Fe, Ni in non-pioneer plants indicated that the PP forest (initially considered as the least polluted) has still been affected by metal pollution. Soil collected in STG was enriched by all elements, however these elements were low available for plant uptake. Metal deposited in leaves and litter was an important sink for soil cycling, nevertheless, these metals are not bioavailable in most cases. Non-pioneer tree species revealed to be more appropriate than pioneer species to indicate the current panorama of the contamination and bioavailability levels of trace metals in the tree community-litter-soil interface of the Atlantic forest remnants included in this study.

Microplastics are widespread in the aquatic environment and thus available for many organisms at different trophic levels. Many scientific papers focus their attention on the study of the effects of microplastics on different species at individual level. Here we performed a global scale meta-analysis focusing our work on the study of the effect of microplastics on the functional traits of aquatic benthic organisms. Overall, microplastics showed a moderate negative effect on the examined functional traits of benthic organisms. Our results show that some crucial functional traits, such as those linked to behaviour and feeding, appear to be unaffected by microplastics. In contrast, traits related to the capacity of organisms to assimilate energy are affected. Moreover, traits with possible effects at population level appear to be negatively affected by microplastics. We discuss how the direct impact of organismal performance may have indirect repercussions at higher levels in the ecological hierarchy and represent a risk for the stability and functioning of the ecosystem.

The ongoing loss of global biodiversity is endangering ecosystem functioning and human food security. While environmental pollutants are well known to reduce fertility, the potential effects of common neonicotinoid insecticides on insect fertility remain poorly understood. Here, we show that field-realistic neonicotinoid exposure can drastically impact male insect fertility. In the laboratory, male and female solitary bees Osmia cornuta were exposed to four concentrations of the neonicotinoid thiamethoxam to measure survival, food consumption, and sperm traits. Despite males being exposed to higher dosages of thiamethoxam, females revealed an overall increased hazard rate for survival; suggesting sex-specific differences in toxicological sensitivity. All tested sublethal concentrations (i.e., 1.5, 4.5 and 10 ng g⁻¹) reduced sperm quantity by 57% and viability by 42% on average, with the lowest tested concentration leading to a reduction in total living sperm by 90%. As the tested sublethal concentrations match estimates of global neonicotinoid pollution, this reveals a plausible mechanism for population declines, thereby reflecting a realistic concern. An immediate reduction in environmental pollutants is required to decelerate the ongoing loss of biodiversity.

As an important form of urban water resource, urban artificial lakes are severely affected by rapid urbanization and interference from human activities. These small lakes are characterized by their unique irregular shape, fragile ecosystem, and relatively closed, stagnant waterbodies. However, few studies have focused on their hydrodynamics and water quality, in particular the restoration methods and mechanisms remaining unclear. The present study applied the MIKE 21 FM model to investigate the effects of water diversion on water quality in a typical urban artificial lake. By considering different flow arrangements, several model scenarios were set up to predict the impacts of water diversion on selected water quality parameter. The results showed that the effectiveness of water diversion was directly related to flow velocity, the relative position to the fresh water inlet, the amount and quality of fresh water and water remaining to be diluted, and the circulation direction of flow field. The inflow–outflow arrangement was the primary factor determining the flow field and NH₃–N variation trends across the lake, and an increased discharge exhibited unequal effects in individual zones. Wind was also important for the formation of flow circulation and pollutant variation. Methods were proposed for enhancing water quality in urban small-scale lakes, including changing the way diversion projects are managed, improving the quality of diverted flow, enhancing flow fluidity, or utilizing wind effects and local topography.

Frequency and intensity of wildfire occurrences are dramatically increasing worldwide due to global climate change, having a devastating effect on the entire ecosystem including plants. Moreover, distribution of fire-smoke can influence the natural environment over very long distances, i.e. hundreds of kilometres. Dry plant matter contains 0.1–0.9% (w/w) sulphur, which is mainly released during combustion into the atmosphere as sulphur dioxide (SO₂) resulting in local concentrations of up to 3000 nL L⁻¹. SO₂ is a highly hazardous gas, which enters plants mostly via the stomata. Toxic sulphite is formed inside the leaves due to conversion of SO₂. Plants as sessile organisms cannot escape from threats, why they evolved an impressive diversity of molecular defence mechanisms. In the present study, two recent wildfires in Germany were evaluated to analyse the effect of SO₂ released into the atmosphere on deciduous trees: the Meppen peat fire in 2018 and the forest fire close to Luebtheen in 2019. Collected leaf material from beech (Fagus sylvatica) and oak (Quercus robur) was examined with respect to detoxification of sulphur surplus due to the exposure to elevated SO₂. An induced stress reaction in both species was indicated by a 1.5-fold increase in oxidized glutathione. In beech leaves, the enzymatic activities of the sulphite detoxification enzymes sulphite oxidase and apoplastic peroxidases were increased 5-fold and a trend of sulphate accumulation was observed. In contrast, oaks did not regulate these enzymes during smoke exposure, however, the constitutive activity is 10-fold and 3-fold higher than in beech. These results show for the first time sulphite detoxification strategies of trees in situ after natural smoke exposure. Beech and oak trees survived short-term SO₂ fumigation due to exclusion of toxic gases and different oxidative detoxification strategies. Beeches use efficient upregulation of oxidative sulphite detoxification enzymes, while oaks hold a constitutively high enzyme-pool available.

Plastic pollution is a new, pressing, environmental topic. Microplastics are considered contaminants of emerging concern and, consequently, microplastic research has grown exponentially in the last decade. Here, current knowledge regarding the impacts of micro- and nanoplastics on terrestrial plants and aquatic macrophytes is discussed, with a special focus on adsorption, uptake and toxicological effects. Our review reveals that a range of plants and macrophytes can adsorb or internalise plastic particles. Both processes depend on particle characteristics such as size and charge, as well as plant features including a sticky or hydrophobic surface layer. This finding is of concern given that plants and aquatic macrophytes are at the bottom of food webs and are a crucial component of the human diet. Therefore, there is a critical need for improved understanding of adsorption, uptake and impacts of micro- and nanoplastics, and the consequences thereof for trophic transfer, food safety and security. Also, a range of stress responses have been observed for many plant and macrophyte species after both short and long-term exposures to plastic particles. Given that some plastic particles can affect plant productivity, we surmise that plastic particles may potentially impact ecosystem productivity and function. Here we present a synthesis and a critical evaluation of the state of knowledge of micro- and nanoplastics and plants and macrophytes, identifying key questions for future research.

Sulfur, an essential macronutrient, plays important roles in plant development and stress mitigation. Sulfur deficiency, a common problem in agricultural soils, may disturb plant stress resistance and xenobiotic detoxification. In the present study, the function and mechanism of limited sulfur nutrition on the residues and phtotoxicity of imidacloprid were investigated in lettuce plants. Sulfur deficiency significantly increased imidacloprid accumulation in lettuce tissues, exacerbated imidacloprid biological toxicity by enhancing the accumulation of toxic metabolites, like imidacloprid-olefin. Simultaneously, imidacloprid-induced detoxification enzymes including cytochromes P450, glutathione S-transferases (GSTs) and glycosyltransferases were inhibited under limited sulfur supply. On the other hand, sulfur deficiency further enhanced the generation of reactive oxygen species and exacerbated lipid peroxidation in lettuce tissues. Sulfur deficiency mainly reduced the abundance of thiol groups, which are essential redox modulators as well as xenobiotic conjugators, and significantly inhibited GSTs expression. These results clearly suggested that sulfur deficiency inhibited the synthesis of sulfur-containing compounds, leading to increased accumulation of pesticide residues and toxic metabolites as well as reduced detoxification capacity, consequently leading to oxidative damage to plants. Therefore, moderate sulfur supply in regions where neonicotinoid insecticides are intensively and indiscriminately used may be an efficient strategy to reduce pesticide residues and the potential risk to ecosystem.

On March 12th, 2020, the WHO declared COVID-19 as a pandemic. The collective impact of environmental and ecosystem factors, as well as biodiversity, on the spread of COVID-19 and its mortality evolution remain empirically unknown, particularly in regions with a wide ecosystem range. The aim of our study is to assess how those factors impact on the COVID-19 spread and mortality by country. This study compiled a global database merging WHO daily case reports with other publicly available measures from January 21st to May 18th, 2020. We applied spatio-temporal models to identify the influence of biodiversity, temperature, and precipitation and fitted generalized linear mixed models to identify the effects of environmental variables. Additionally, we used count time series to characterize the association between COVID-19 spread and air quality factors. All analyses were adjusted by social demographic, country-income level, and government policy intervention confounders, among 160 countries, globally. Our results reveal a statistically meaningful association between COVID-19 infection and several factors of interest at country and city levels such as the national biodiversity index, air quality, and pollutants elements (PM₁₀, PM₂.₅, and O₃). Particularly, there is a significant relationship of loss of biodiversity, high level of air pollutants, and diminished air quality with COVID-19 infection spread and mortality. Our findings provide an empirical foundation for future studies on the relationship between air quality variables, a country’s biodiversity, and COVID-19 transmission and mortality. The relationships measured in this study can be valuable when governments plan environmental and health policies, as alternative strategy to respond to new COVID-19 outbreaks and prevent future crises.

Several environmental pollutants, including pesticides, herbicides and persistent organic pollutants play an important role in the development of chronic diseases. However, most studies have examined environmental pollutants toxicity in target organisms or using a specific toxicological test, losing the real effect throughout the ecosystem. In this sense an integrative environmental risk of pollutants assessment, using different model organisms is necessary to predict the real impact in the ecosystem and implications for target and non-target organisms.The objective of this study was to use alachlor, a chloroacetanilide herbicide responsible for chronic toxicity, to understand its impact in target and non-target organisms and at different levels of biological organization by using several model organisms, including membranes of dipalmitoylphosphatidylcholine (DPPC), rat liver mitochondria, bacterial (Bacillus stearothermophilus), plant (Lemna gibba) and mammalian cell lines (HeLa and neuro2a).Our results demonstrated that alachlor strongly interacted with membranes of DPPC and interfered with mitochondrial bioenergetics by reducing the respiratory control ratio and the transmembrane potential. Moreover, alachlor also decreased the growth of B. stearothermophilus and its respiratory activity, as well as decreased the viability of both mammalian cell lines. The values of TC₅₀ increased in the following order: Lemna gibba < neuro2a < HeLa cells < Bacillus stearothermophilus. Together, the results suggest that biological membranes constitute a putative target for the toxic action of this lipophilic herbicide and point out the risks of its dissemination on environment, compromising ecosystem equilibrium and human health.