Application of nanopesticides may substantially increase surface attachment and internalization of engineered nanoparticles (ENPs) in food crops. This study investigated the role of stomata in the internalization of silver nanoparticles (Ag NPs) using abscisic acid (ABA)-responsive ecotypes (Ler and Col-7) and ABA-insensitive mutants (ost1-2 and scord7) of Arabidopsis thaliana in batch sorption experiments, in combination with microscopic visualization. Compared with those of the ABA-free control, stomatal apertures were significantly smaller for the Ler and Col-7 ecotypes (p ˂ 0.05) but remained unchanged for the ost1-2 and scord7 mutants, after exposure to 10 μM ABA for 1 h. Generally Ag NP sorption to the leaves of the Ler and Col-7 ecotypes treated with 10 μM ABA was lower than that in the ABA-free control, mainly due to ABA-induced stomatal closure. The difference in Ag NP sorption with and without ABA was less pronounced for Col-7 than for Ler, suggesting different sorption behaviors between these two ecotypes. In contrast, there was no significant difference in foliar sorption of Ag NPs by the ost1-2 and scord7 mutants with and without ABA treatment. Ag NPs were widely attached to the Arabidopsis leaf surface, and found at cell membrane, cytoplasm, and plasmodesmata, as revealed by scanning electron microscopy and transmission electron microscopy, respectively. These results highlight the important role of stomata in the internationalization of ENPs in plants and may have broad implications in foliar application of nanopesticides and minimizing contamination of food crops by ENPs.

Indoor airborne microplastics fibers (MPFs) are emerging contaminants of growing concern. Nowadays, air conditioners (ACs) are widely used in indoor environments. However, little is known about their impact on the distribution of indoor MPFs. In this study, we first disclosed the prevalence of MPF contamination in filters for indoor split ACs used in living rooms, dormitories, and offices. The average density of microfibers was 1.47–21.4 × 10² items/cm², and a total 27.7–35.0% of fibers were MPFs. Of these fibers, the majority were polyester (45.3%), rayon (27.8%), and cellophane (20.1%). We further tracked the long-term accumulation of MPFs on AC filters in three types of rooms, and demonstrated that dormitories showed relatively heavy accumulation especially after running for 35–42 days. Furthermore, we found that simulative AC filters which had been lined with PET MPFs could effectively release those MPFs into indoor air, propelling them away from the ACs at varying distances. Statistical analysis showed that the estimated daily intake of MPFs (5–5000 μm length) from AC filters would increase gradually with their usage, with the intake volume reaching up to 11.2 ± 2.2–44.0 ± 8.9 items/kg-BW/day by the 70th day, although this number varied among people of different ages. Altogether, these findings suggest that AC filters can act as both a sink and a source of microplastics fibers. Therefore, AC filters should be evaluated not only for their substantial impact on the distribution of indoor airborne MPFs, but also for their role in the prevalence of the related health risks.

The 2,4-dichlorophenoxyacetic acid (2,4-D) is an auxinic herbicide widely used in agriculture that is effective in controlling weeds. It is directly applied to the soil, to ponds or sprayed onto crops; thus, it can progressively accumulate in environmental compartments and affect non-target organisms. The aim of the present meta-analytic review is to investigate the toxic effects of 2,4-D, based on a compilation of results from different studies, which were synthesized to form a statistically reliable conclusion about the lethal effect of potentially ecological concentrations of 2,4-D in several animal species. The search was carried out in the Web of Science and Scopus databases. After the selection process was over, 87 datasets were generated and analyzed. The overall effect has indicated significant increase in the mortality rate recorded for animals exposed to environmental concentrations of 2,4-D compared to the control in the experiment (unexposed animals). The segregation of animals into taxonomic categories has shown that fish and birds presented higher mortality rates after exposure to the investigated substance. The present meta-analysis indicated larval and adult animals were susceptible among the ontogenetic development stages. Juvenile individuals exposed to different 2,4-D concentrations did not show significant difference in comparison to the control. Organisms exposed to 2,4-D immersion were the most impacted compared to those exposed by oral, spray and contact. Animals subjected to commercial formulation presented higher mortality rate than the analytical standard. Thus, 2,4-D can, in fact, increase mortality rate in animals, but it depends on species sensitivity, life stage and exposure route. This is the first meta-analytical study evaluating the mortality rate after 2,4-D exposure in several animal species.

Chlorpyrifos (CPF), as an organophosphate insecticide extensively used in the modern agricultural system, has been gradually banned in many countries due to its reported health risks to organisms, including humans. This study used simulated paddy field experiments and carbon-14 tracing to explore the possibility of reducing environmental risks of chlorpyrifos application through appropriate agronomic practice. Results showed ¹⁴C-CPF concentration in rice plants planted in the red soil (RS) was significantly higher than that in black soil (BS) and fluvo-aquic soil (FS). The application of biochar and chicken manure in RS reduced ¹⁴C-CPF accumulation in rice plants, and the content of ¹⁴C-CPF in rice grains decreased by 25% and 50%, respectively. Adding biochar to all three soils reduced the migration of ¹⁴C-CPF, especially in FS with the highest risk of ¹⁴C-CPF migration. The addition of chicken manure in FS reduced the migration of ¹⁴C-CPF and the total residual amount of ¹⁴C-CPF in the soil. In addition, chicken manure treatment increased the formation of ¹⁴C-bound residues (BRs) in soils and changed the distribution ¹⁴C-BRs in humus. The results indicated that the degree of environmental risks associated with the CPF application varies with soil types and could be reduced by introducing suitable exogenous organic matter into different soils, which is of great significance for guiding the scientific application of chlorpyrifos in agronomic practices.

Cell phone use and radio-frequency electromagnetic radiation (RF-EMF) are rapidly increasing and may be associated with lower semen quality, yet results from epidemiological studies are inconclusive. Information on electronic devices use was collected through standard questionnaires from 1454 men aged 22–45 years old. Semen volume, sperm concentration, total sperm count, total motility, progressive motility, and normal morphology in repeated specimens were determined by trained clinical technicians. Percent changes [95% confidence intervals (CIs)] were estimated as (10ᵝ−1) × 100 for electronic devices use associated with repeated sperm quality parameters in the linear mixed-effect models. After adjusting for multiple confounders, we found significant inverse associations of total duration of electronic devices use with sperm progressive motility and total motility, duration of cell phone and computer use with sperm concentration, progressive motility, and total motility (all P < 0.05). No significant association was found between cell phone/computer use alone and sperm quality parameters. Moreover, per hour increase of time spent on cell phone talking was associated with decreased sperm concentration and total count by an average of −8.0% (95% CI: −15.2%, −0.2%) and −12.7% (95% CI: −21.3%, −3.1%), respectively. Besides, daily calling time was associated with lower sperm progressive motility and total motility among those who used headsets during a call (P for interaction <0.05). In conclusion, our study suggested that more time spent on electronic devices use had a modest reduction effect on semen quality. Daily calling time was significantly associated with lower sperm concentration and total count, and using headsets during a call appeared to aggravate the negative association between daily calling time and sperm motility. Additional studies are needed to confirm these findings.

A growing number of studies report associations between air pollution and COVID-19 mortality. Most were ecological studies at the county or regional level which disregard important local variability and relied on data from only the first few months of the pandemic. Using COVID-19 deaths identified from death certificates in California, we evaluated whether long-term ambient air pollution was related to weekly COVID-19 mortality at the census tract-level during the first ∼12 months of the pandemic. Weekly COVID-19 mortality for each census tract was calculated based on geocoded death certificate data. Annual average concentrations of ambient particulate matter <2.5 μm (PM₂.₅) and <10 μm (PM₁₀), nitrogen dioxide (NO₂), and ozone (O₃) over 2014–2019 were assessed for all census tracts using inverse distance-squared weighting based on data from the ambient air quality monitoring system. Negative binomial mixed models related weekly census tract COVID-19 mortality counts to a natural cubic spline for calendar week. We included adjustments for potential confounders (census tract demographic and socioeconomic factors), random effects for census tract and county, and an offset for census tract population. Data were analyzed as two study periods: Spring/Summer (March 16-October 18, 2020) and Winter (October 19, 2020–March 7, 2021). Mean (standard deviation) concentrations were 10.3 (2.1) μg/m³ for PM₂.₅, 25.5 (7.1) μg/m³ for PM₁₀, 11.3 (4.0) ppb for NO₂, and 42.8 (6.9) ppb for O₃. For Spring/Summer, adjusted rate ratios per standard deviation increase were 1.13 (95% confidence interval: 1.09, 1.17) for PM₂.₅, 1.16 (1.11, 1.21) for PM₁₀, 1.06 (1.02, 1.10) for NO₂, and 1.09 (1.04, 1.14) for O₃. Associations were replicated in Winter, although they were attenuated for PM₂.₅ and PM₁₀. Study findings support a relation between long-term ambient air pollution exposure and COVID-19 mortality. Communities with historically high pollution levels might be at higher risk of COVID-19 mortality.

Estuaries are one of the most valuable biomes on earth. Although humans are highly dependent on these ecosystems, anthropogenic activities have impacted estuaries worldwide, altering their ecological functions and ability to provide a variety of important ecosystem services. Many anthropogenic stressors combine to affect the soft sedimentary habitats that dominate estuarine ecosystems. Now, due to climate change, estuaries and other marine areas might be increasingly exposed to the emerging threat of megafires. Here, by sampling estuaries before and after a megafire, we describe impacts of wildfires on estuarine benthic habitats and justify why megafires are a new and concerning threat to coastal ecosystems. We (1) show that wildfires change the fundamental characteristics of estuarine benthic habitat, (2) identify the factors (burnt intensity and proximity to water's edge) that influence the consequences of fires on estuaries, and (3) identify relevant indicators of wildfire impact: metals, nutrients, and pyrogenic carbon. We then discuss how fires can impact estuaries globally, regardless of local variability and differences in catchment. In the first empirical assessment of the impact of wildfires on estuarine condition, our results highlight indicators that may assist waterway managers to empirically detect wildfire impacts in estuaries and identify catchment factors that should be included in fire risk assessments for estuaries. Overall, this study highlights the importance of considering fire threats in current and future estuarine and coastal management.

Freshwater environments are more sensitive to anthropogenic influences and usually contain higher concentrations of pollutants than marine environments. Microplastic pollution causes additional stress on freshwater animals; yet, studies evaluating the microplastic occurrence in freshwater biota are still limited. In this study, microplastic occurrence in the gastrointestinal tracts (GIT) and gill of commercial fish species (Prussian carp Carassius gibelio (Bloch, 1782); Abu mullet Planiliza abu (Heckel, 1843); Common carp Cyprinus carpio Linnaeus, 1758; European ell Anguilla Anguilla (Linnaeus, 1758); North African catfish Clarias gariepinus (Burchell, 1822); Goldfish Carassius auratus (Linnaeus, 1758) were reported from Orontes River. MPs abundance in the GIT and gill of six species were found as 5.1 ± 2 MPs fish⁻¹ and 4.4 ± 2 MPs fish⁻¹ with an occurrence of 95% and 74%, respectively. The majority of extracted microplastics were fiber, black and less than 1000 μm in size. FTIR analysis determined the main polymer types as polyester (50%), high-density polyethylene (HDPE) (10%), polypropylene (PP) (8%) and polyethylene terephthalate (PET) (5%). High MPs abundance and frequency of occurence indicate the exposure of microplastic pollution in freshwater biota which could threat the health of both individuals and consumers. Results obtained in this study will increase the acknowledgement of MPs pollution in the Orontes River. Also, this study will provide data to the administrators to set up necessary legislations in freshwater ecosystems.

Among wild birds, lead (Pb) exposure caused by ingestion of ammunition is a worldwide problem. We aimed to reveal the behavior and toxic effect of Pb caused by ingesting Pb shots in waterfowl. Four male, eight-week old Muscovy ducks (Cairina moschata) were given three Pb shots (approximately 240 mg in total) orally and then fed for 29 days after exposure, simulating a low-dose Pb exposure in wild waterfowl. During the breeding period, blood samples were collected 10 times, and fecal samples every day. Additionally, 22 fresh tissue and 6 bone samples were obtained from each duck through the dissection. Although there were no gross abnormalities, the maximum blood Pb concentration of each duck ranged from 0.6 to 3.7 mg/L, reaching a threshold concentration indicative of clinical symptoms (>0.5 mg/L). δ-aminolevulinic acid dehydratase declined one day after exposure and remained low throughout the feeding period. Hematocrit also tended to decrease, indicating signs of anemia. The highest Pb accumulation was observed in the bones, followed by the kidneys, intestinal tracts, and liver. High Pb accumulation in the bones, which are known to have a long Pb half-life, suggested that Pb would remain in the body and possibly affect bird health beyond 28 days after exposure. Gene expression analysis showed a significant increase in the expression of the toll-like receptor-3 gene, which is involved in virus discrimination in the liver, suggesting a disruption of the immune system. Microbiota analyses showed a correlation between the blood Pb concentration and the abundances of Lachnospiraceae and Ruminococcaceae, suggesting that Pb affects lipid metabolism. These results provide fundamental data on Pb exposure in wild birds and a new perspective on the damage such exposure causes.

Growing evidence recommends that radiofrequency radiations might be a new type of environmental pollutant. The consequences of RFR on the human immune system have gained considerable interest in recent years, not only to examine probable negative effects on health but also to understand if RFR can modulate the immune response positively. Although several studies have been published on the immune effects of RFR but no satisfactory agreement has been reached. Hence this review aims to evaluate the RFR modulating impacts on particular immune cells contributing to various innate or adaptive immune responses. In view of existing pieces of evidence, we have suggested an intracellular signaling cascade responsible for RFR action. The bio-effects of RFR on immune cell morphology, viability, proliferation, genome integrity, and immune functions such as ROS, cytokine secretion, phagocytosis, apoptosis, etc. are discussed. The majority of existing evidence point toward the possible shifts in the activity, number, and/or function of immunocompetent cells, but the outcome of several studies is still contradictory and needs further studies to reach a conclusion. Also, the direct association of experimental studies to human risks might not be helpful as exposure parameters vary in real life. On the basis of recent available literature, we suggest that special experiments should be designed to test each particular signal utilized in communication technologies to rule out the hypothesis that longer exposure to RFR emitting devices would affect the immunity by inducing genotoxic effects in human immune cells.