Thermo-chemical processes for converting plastic wastes into useful materials are considered promising technologies to mitigate the environmental pollution caused by plastic wastes. In this study, polyethylene terephthalate (PET) plastic wastes were used to develop cost-effective and value-added porous carbons; the developed porous carbons were subsequently tested for capturing CF₄, a greenhouse gas with a high global-warming potential. The activation temperature was varied from 600 °C to 1000 °C and the mass ratio of KOH/carbon ranged from 1 to 3 in the preparation process and their effects on the textural properties and CF₄-capture performance of the PET plastic waste-derived porous carbons were investigated. The CF₄-adsorption uptake was dictated by the specific surface area and pore volume of narrow micropores less than 0.9 nm in diameter. PET-K(2)700, which was developed by KOH activation at 700 °C and KOH/carbon mass ratio of 2, showed the highest CF₄-adsorption uptake of 2.43 mmol g⁻¹ at 25 °C and 1 atm. Also, the CF₄-adsorption data were fitted well with the Langmuir isotherm model and pseudo second-order kinetic model. The PET plastic waste-derived porous carbons exhibited a high CF₄ uptake, good CF₄/N₂ selectivity at relatively low CF₄ pressures, easy regeneration, rapid adsorption/desorption kinetics, and excellent recyclability, which are promising for practical CF₄-capture applications.

An increasing number of epidemiological studies have examined air pollution as a possible contributor to adverse sleep health, but results are mixed. The aims of this systematic review are to investigate and summarize the associations between exposures to air pollutants and various sleep measures across the lifespan. PubMed, CINAHL, Cochrane, Scopus, Web of Science, and PsycInfo were searched through October 2019 to identify original data-based research examining direct epidemiological associations between ambient and indoor air pollution exposures and various sleep health measures, including sleep quality, sleep duration, sleep disturbances, and daytime sleepiness. Twenty-two articles from 2010 to 2019 were selected for inclusion in this review, including a wide range of study populations (from early childhood to elderly) and locations (10 Asian, 4 North American, 3 European, 5 other). Due to variation in both exposure and outcome assessments, conducting a meta-analysis was not plausible. Twenty-one studies reported a generally positive association between exposure and poor sleep quality. While most studies focused on ambient air pollutants, five assessed the specific effect of indoor exposure. In children and adolescents, increased exposure to both ambient and indoor pollutants is associated with increased respiratory sleep problems and a variety of additional adverse sleep outcomes. In adults, air pollution exposure was most notably related to sleep disordered breathing. Existing literature generally shows a negative relationship between exposures to air pollution and sleep health in populations across different age groups, countries, and measures. While many associations between air pollution and sleep outcomes have been investigated, the mixed study methods and use of subjective air pollution and sleep measures result in a wide range of specific associations. Plausible toxicological mechanisms remain inconclusive. Future studies utilizing objective sleep measures and controlling for all air pollution exposures and individual encounters may help ameliorate variability in the results reported by current published literature.

Butylated hydroxytoluene (BHT) is one of the most frequently used synthetic phenolic antioxidants added to food and consumer products such as plastics as a preservative. Due to its high production volume, BHT has been detected in aquatic environments, raising concerns about sub-lethal toxicity. However, there are limited toxicological data for BHT, especially in fish. In this study, zebrafish embryos were exposed to BHT at concentrations ranging 0.01–100 μM for up to 6 days post fertilization (dpf). Acute toxicity was assessed, and experiments revealed that BHT had a 96 h LC50 value of 57.61 μM. At sub-lethal doses (0.1–60 μM), BHT markedly decreased heart rates of zebrafish embryos at 48 h and 72 h by ∼25–30%. Basal and maximal respiration of zebrafish embryos at 24 hpf were decreased by 59.3% and 41.4% respectively following exposure to 100 μM BHT. Behavior in zebrafish was measured at 6 dpf following exposures to 0.01–10 μM BHT. Locomotor behaviors (e.g. total distance moved and velocity) were significantly increased in larvae at doses higher than 0.1 μM BHT. In addition, dark-avoidance behavior was decreased following exposure to 0.01 μM BHT, while conversely, it was increased in zebrafish exposed to 0.1 μM BHT. To investigate potential underlying mechanisms that could explain behavioral changes, transcripts involved in dopamine signaling were measured. Relative expression of dat mRNA was increased in larval fish from the 0.01 μM BHT treatment, while there were no effects on dat mRNA levels at higher concentrations. The mRNA levels of drd3 were decreased in zebrafish from the 1 μM BHT treatment. Taken together, BHT can affect the expression of the dopamine system, which is hypothesized to be related to the abnormal anxiety-associated behavior of larval zebrafish.

Organic carbon (OC) can help control greenhouse gas emissions by participating in biogeochemical reactions and preventing the migration of contaminants in groundwater systems. The association of OC with Fe (Iron) oxide minerals plays a significant role in stabilizing OC and regulating the biogeochemical cycles of OC on the earth’s surface. Reclaiming farmland from lakes changes an original lake into a wetland, but the destiny of Fe bound-OC in the underlying aquitard during this process has been poorly understood. The mechanisms of migration and transformation of Fe bound-OC were investigated in subsurface aquitard sediments of three typical boreholes in the Chen Lake wetland, central China. The Fe bound-OC content in the natural sedimentary conditions (borehole A), transition area (borehole B), and intensive reclamation area (borehole C) were 0.17–3.87, 0.28–3.98 and 0.13–7.08 mg g⁻¹, respectively. The reclamation changed the redox, water, and infiltration conditions of the surface environment, resulting in a transformation of Fe oxides phases, and then cause the change of content and structure of Fe bound-OC. The fresh organic matter provided by undecomposed crops causes oxygen- and nitrogen-rich compounds to combine with Fe oxides extensively through adsorption, resulting in higher δ¹³C values of Fe bound-OC than non-Fe bound-OC. Fe bound-OC has strong resistance to biodegradation. The Fe bound-OC: total OC ratios generated by adsorption and coprecipitation on the surface layer (0 to −3.5 m) of borehole C was 10.37% and 18.86%, 6.92% and 12.46% higher than those of boreholes A and B, respectively. Coprecipitation has a stronger OC-binding ability and enriches more carboxylates and aromatics, while adsorption gradually assumed a dominant position in OC-Fe interaction in deep aquitard. The reduction dissolution of Fe oxide causes Fe bound-OC to transfer into pore water, leading to an increase of Fe ion and dissolved OC in deep strata.

Thiacloprid is widely used in agriculture and may affect pollinators. However, its molecular effects are poorly known. Here, we report the global gene expression profile in the brain of honey bee foragers assessed by RNA-sequencing. Bees were exposed for 72 h to nominal concentrations of 25 and 250 ng/bee via sucrose solution. Determined residue concentrations by LC-MS/MS were 0.59 and 5.49 ng/bee, respectively. Thiacloprid exposure led to 5 and 71 differentially expressed genes (DEGs), respectively. Nuclear genes encoding mitochondrial ribosomal proteins and enzymes involved in oxidative phosphorylation, as well as metabolism enzymes and transporters were altered at 5.49 ng/bee. Kyoto Encylopedia of Genes and Genomes (KEGG) analysis revealed that mitochondrial ribosome proteins, mitochondrial oxidative phosphorylation, pyrimidine, nicotinate and nicotinamide metabolism and additional metabolic pathways were altered. Among 21 genes assessed by RT-qPCR, the transcript of farnesol dehydrogenase involved in juvenile hormone III synthesis was significantly down-regulated. Transcripts of cyp6a14-like and apolipophorin-II like protein, cytochrome oxidase (cox17) and the non-coding RNA (LOC102654625) were significantly up-regulated at 5.49 ng/bee. Our findings indicate that thiacloprid causes transcriptional changes of genes prominently associated with mitochondria, particularly oxidative phosphorylation. This highlight potential effects of this neonicotinoid on energy metabolism, which may compromise bee foraging and thriving populations at environmentally relevant concentrations.

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) has been demonstrated to be transferred from parental animals to their offspring. However, whether parental exposure to environmental concentrations of TDCIPP show neurodevelopmental toxicity in the F1 generation and the possible underlying mechanism remain unclear. Therefore, in this study, zebrafish embryos were exposed to environmental concentrations of TDCIPP (3, 30 and 300 ng L⁻¹) for 120 days. The effects of exposure on motor behaviors, neurotransmitter levels, DNA methylation, and gene expression of F1 larvae were investigated. Parental exposure left TDCIPP residues in F1 eggs as well as reduced body length of F1 larvae. Moreover, parental exposure significantly reduced swimming activity in F1 5 dpf larvae, although it did not significantly alter serotonin, dopamine, 3,4-dihydroxyphenylacetic acid, γ-aminobutyrate, and acetylcholine levels. Genes encoding DNA methylation transferases (dnmt3aa and dnmt1) were downregulated in F1 larvae. Reduced representation bisulfite sequencing analysis revealed 446 differentially methylated regions and enriched neuronal cell body Gene Ontology term in F1 generation. Correlation analysis between the expression of genes related to neural cell body and swimming speed indicated that solute carrier family 1 member 2b (slc1a2b) downregulation might be responsible for the inhibition of motor behaviors. Furthermore, bisulfite amplicon sequencing analysis confirmed hypermethylation of the promoter region of slc1a2b in F1 larvae following parental exposure to 300 ng L⁻¹ TDCIPP, which might have led to significant downregulation of gene expression and, in turn, influenced the motor behaviors. These results indicate that parental exposure to environmental concentrations of TDCIPP alters DNA methylation, downregulates gene expressions and, thus inducing developmental neurotoxicity, in F1 larvae.

Microplastics have received growing attention as carriers of organic pollutants in the water environment. To better understand the contribution of hydrophobic interaction, hydrogen-bonding interaction, π-π interaction and electrostatic interaction on the adsorption of hydrophilic compounds on microplastics and their adsorption behavior in natural waters, polyethylene terephthalate (PET, <150 μm) was used as an adsorbent and 4-chlorophenol (MCP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) were used as adsorbates. The results of batch adsorption experiments showed that chlorophenols (CPs) reached adsorption sites of PET through film diffusion and intra-particle diffusion. pH greatly affected the adsorption capacity. Hydrophobic interaction was the main adsorption mechanism of undissociated CPs on PET. Hydrogen-bonding interaction was also an adsorption mechanism between undissociated CPs and PET, and the contribution of hydrogen-bonding interaction to adsorption decreased with the increase of chlorine content. Meanwhile, the increase of chlorine content was favorable to the hydrophobic interaction between undissociated CPs and PET. However, higher chlorine content CPs with lower pKₐ values tended to dissociate at neutral pH condition and resulted in stronger electrostatic repulsion with PET. The increase of solution ionic strength and fulvic acid content negatively affected the adsorption of DCP and TCP on PET, but did not show significant impacts on MCP adsorption. Similarly, the adsorption capacity obtained using Taihu lake water and Bohai seawater as matrices was much lower than that using laboratory water for both DCP and TCP, while the adsorption coefficient (Kd) of MCP remained at approximately 10.6 L/kg to 11.4 L/kg in the three different solution matrices. The Kd values exhibited using natural water matrices consistently followed the order of DCP > MCP > TCP. This study provides insights into the fate of CPs in the presence of microplastics and suggests that the potential risks posed by CPs and microplastics to aqueous ecosystems merit further investigation.

With increasing release of nanoparticles (NPs) into the environment, soil organisms likely suffer from high dose and long duration of NPs contamination, while the effect of NPs across multiple generations in soil is rarely studied. Herein, we investigated how multigenerational exposure to different crystal forms (anatase, rutile, and their mixture) of TiO₂ NPs (nTiO₂) affected the survival, behavior, physiological and biochemical traits, and lifespan of nematodes (C. elegans) in a paddy soil. The soil property changed very slightly after being spiked with nTiO₂, and the toxicities of three nTiO₂ forms were largely comparable. The nTiO₂ exposure adversely influenced the survival and locomotion of nematodes, and increased intracellular reactive oxygen species (ROS) generation. Interestingly, the toxic effect gradually attenuated and the lifespan of survived nematodes increased from the P0 to F3 generation, which was ascribed to the survivor selection and stimulatory effect. The lethal effect and the increased oxidative stress may continuously screen out offspring possessing stronger anti-stress capabilities. Moreover, key genes (daf-2, age-1, and skn-1) in the insulin/IGF-like signaling (IIS) pathway actively responded to the nTiO₂ exposure, which further optimized the selective expression of downstream genes, increased the antioxidant enzyme activities and antioxidant contents, and thereby increased the stress resistance and longevity of survived nematodes across successive generations. Our findings highlight the crucial role of bio-responses in the progressively decreased toxicity of nTiO₂, and add new knowledge on the long-term impact of soil nTiO₂ contamination.

The widespread use of nanoparticles (NPs) has drawn considerable attention because of their potential toxicity and the environmental consequences thereof. However, the effects of the exposure route and life stage of an organism on the bioaccumulation and toxicity of NPs are largely unknown. In the present study, we investigated the accumulation kinetics (uptake, assimilation, and efflux) and tissue distribution of waterborne and dietary hematite NPs (HemNPs) during three life stages (embryo, larva, and adult) of the zebrafish Danio rerio. For all zebrafish life stages, the waterborne accumulation of well-dispersed HemNPs increased linearly with exposure time but decreased after reaching a maximum. The increase in HemNPs accumulation followed the order embryo > larva > adult. Compared with the waterborne route, the dietary accumulation of HemNPs in larval and adult zebrafish fluctuated, reaching a maximum after each food refreshment and then decreasing until the next food addition. Similar to waterborne exposure, adult fish accumulated less dietary HemNPs than did larvae. Nevertheless, dietary HemNPs mostly accumulated in the intestinal tract, with smaller amounts in the truncus, head, and gills, as compared with their waterborne counterparts. Moreover, in the gonad no dietary HemNPs were detected whereas accumulation via waterborne HemNPs was significant. Despite the low assimilation efficiency of dietary HemNPs, biodynamic modeling showed that the diet was the main source of particle accumulation in zebrafish. Thus, both the life stage and the exposure route should be considered in evaluations of the environmental risks of NPs.

The transmission and accumulation of trace metals in marine food webs have a profound influence on the structure and function of marine environment. In order to quantitatively assess the trophic transfer behaviors of eight common metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in simplified five-trophic level marine food webs, a total of 9929 biological samples from 61 studies published between 2000 and 2019, involving 154 sampling sites of 33 countries/regions, were re-compiled using meta-analysis. Based on concentration-trophic level weighted linear regression and predator/prey comparison, the food web magnification factor (FWMF) and the biomagnification factor (BMF) were calculated, respectively. The results showed dissimilar trophic transfer behaviors of these metals in global marine food webs, in which As and Ni tended to be efficiently biodiluted with increasing trophic levels (FWMFs < 1, p < 0.01), while Hg, Pb and Zn trophically biomagnified (FWMFs > 1, p < 0.05). However, Cd, Cr and Cu presented no biomagnification or biodilution trend (p > 0.05). The values of FWMFs were ranked as: Hg (2.01) > Pb (1.81) > Zn (1.15) > Cu (1.13) > Cr (0.951) > Cd (0.850) > Ni (0.731) > As (0.494). In terms of specific predator-prey relationship, Pb showed significant biodilution from tertiary consumers (TC) to top predators (BMF < 1, p < 0.05), whereas Cd and Cu displayed obvious biomagnification from primary consumers (PC) to secondary consumers (SC) (BMFs >1, p < 0.05). Additionally, when Cu and Zn were transferred from SC to TC, and primary producers to PC, clear biodilution and biomagnification effects were observed, respectively (p < 0.05). Further analysis indicated that the average concentration of Hg in five-trophic level marine food webs of developed countries (0.904 mg kg⁻¹ dw) was more noticeable (p < 0.05) than that of developing countries (0.549 mg kg⁻¹ dw).