Gabapentin-lactam (GBP-L) is a transformation product (TP) of gabapentin (GBP), a widely used anti-epileptic pharmaceutical. Due to its high persistence, GBP-L has been frequently detected in the surface water. However, the effects of GBP-L on aquatic organisms have not been thoroughly investigated. In the present study, zebrafish (Danio rerio) embryos as a model organism were used to study the impacts of GBP-L in terms of embryos LC₅₀, spontaneous movement at 24 hpf (hours post fertilization), heartbeat rates at 48 hpf, and body length at 72 hpf, with the concentrations of GBP-L down to 0.01 μg/L, covering its environmental concentrations. Various biomarkers from nervous, antioxidant and immune systems of zebrafish larvae were analyzed, including acetylcholinesterase, acetylcholine, dopamine, gamma-aminobutyric acid, superoxide dismutase, catalase, glutathione S-transferase, C reactive protein, and lysozyme, to assess its toxicity on these systems. RT-qPCR was then used to further verify the results and explain the toxicological mechanism at the gene level. The results demonstrated that GBP-L is much more toxic than its parent compound, and could lead to adverse impacts on the aquatic organisms even at every low concentrations.

Sessile benthic organisms are considered good bioindicators for monitoring environmental quality of coastal ecosystems. However, these environments are impacted by new pollutants such as microplastics (MPs), where there is limited information about organisms that can be used as reliable bioindicators of these emerging contaminants. We evaluated MP concentrations in three compartments: surface sediment, water and in three marine sponge species (Haliclona implexiformis, Halichondria melanadocia and Amorphinopsis atlantica), to determine whether these organisms accumulate MPs and reflect their possible sources. Results showed MPs in all three compartments. Average concentrations ranged from 1861 to 3456 items kg⁻¹ of dry weight in marine sponges, 130 to 287 items L⁻¹ in water and 6 to 11 items kg⁻¹ in sediment. The maximum MP concentration was in the sponge A. atlantica, which registered 5000 items kg⁻¹ of dry weight, in water was 670 items L⁻¹ and in sediment was 28 items kg⁻¹, these values were found in the disturbed study area. The three sponge species exhibited MP bioaccumulation and showed significant differences between disturbed and pristine sites (F = 11.2, p < 0.05), suggesting their use as bioindicators of MP.

This work demonstrated the development of nanofiber templated metal oxide nanocomposites by hydrothermal and calcination methods for photocatalytic degradation using Congo red (CR) as model pollutant. Herein, we developed PAN/CuO–ZnO nanocomposites by the electrospinning technique followed by heat treatment process i.e hydrothermal and calcination. The obtained nanofibrous composites were characterized by various analytical techniques such as X-Ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TG), High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Photoluminescence (PL) and UV–Vis diffuse reflectance spectroscopy (DRS) studies. The results demostrated that the nanocomposites obtained through calcination possess better optical response with robust electronic structures. This is due to the better charge separation of excited electron-hole pairs of p-n heterostructured PAN/CuO–ZnO hybrid nanocomposites. The photocatalytic efficiency is found to be 98% and 93% for nanocomposites obtained through calcination and hydrothermal methods respectively. The reusability studies confirmed the stability and viability of multiple utilizations of photocatalysts. Furthermore, the photocatalytic mechanism corroborated the photocatalytic properties of the integrated facile nanofibrous-metallic (PAN/CuO–ZnO) composites and hence can be implemented in water remediation effectively.

The general population is continuously exposed to phthalates via various consumer products. Epidemiological research relating phthalate exposure to thyroid function during non-developmental periods is limited. This study aimed to investigate the associations between specific serum phthalate metabolites and indicators of thyroid function in adults. We measured 10 serum phthalate metabolites and thyroid hormones – total triiodothyronine (TT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) – in a subsample of 207 adults from the GraMo cohort. This subsample was made up of men and women (in equal proportions) of middle age (49 ± 17 years) and from Southern Spain (province of Granada). Data on age, sex, body mass index, residence area, tobacco use, alcohol consumption and attained education were obtained from a questionnaire. Phthalate metabolites were log-transformed and categorized into tertiles. Cross-sectional associations of each metabolite with thyroid hormones were analyzed using multivariable-adjusted linear regression models. The mixture effect of metabolite phthalates was assessed using weighted quantile sum regression. After multivariable-adjustment, the following phthalate metabolites were significantly associated with TT3 in a dose-response manner: MMP (β = 0.90: 95% confidence interval 0.68,1.12), MEP (β = 0.67: 0.44, 0.90), MiBP (β = 0.49: 0.21, 0.77), MiDP (β = 0.27: 0.03, 0.52), MBzP (β = 0.51: 0.28, 0.73), MEHP (β = −0.59: −0.82, −0.35) and MiNP (β = -0.43: −0.71, −0.14), when comparing highest vs. lowest exposed. The sum of all metabolites was also linked to FT4 levels. No significant associations were observed for TSH except for MiNP. Although phthalate metabolites with different molecular weight showed opposite associations, overall metabolite concentrations seem to associate with increased TT3 and FT4 serum levels. The cross-sectional nature of this analysis limits causal inference.

Sediment remediation in eutrophic aquatic ecosystems is imperative, but effective ecological measures are scarce. A pilot-scale trial investigated sediment remediation by the addition of Tubifex tubifex. The results showed that the addition of T. tubifex accelerated sediment organic matter (OM) and nitrogen (N) loss, with averages of 7.7% and 75.1% increased loss (IL) compared to treatments without T. tubifex in the 60-day experiment, respectively. The percentages of the increased in water to the IL in sediment were only 0.6%, 0.21%, 2.1% and 6.3% for NH₄⁺-N, NOₓ⁻-N, TN and COD, respectively, at the end of the experiment. The absolute abundances of the nitrifying genes AOA and AOB; the denitrifying genes napA, nirS, nirK, cnorB and nosZ; and the anaerobic ammonia oxidation gene anammox increased 2.3- to 11.0-fold with the addition of T. tubifex. Therefore, the addition of T. tubifex is an effective strategy for sediment remediation by accelerating OM and N loss in sediment without substantially increasing the water N concentration.

Pollutants in wastewater and exhaust gas bring out serious concerns to public health and the environment. Biochar can be developed as a sustainable adsorbent originating from abundant bio-wastes, such as agricultural waste, forestry residue, food waste and human waste. Here we highlight the state-of-the-art research progress on pyrochar and hydrochar for the sorption of pollutants (heavy metal, organics, gas, etc) in wastewater and exhaust gases. The adsorption performance of pyrochar and hydrochar are compared and discussed in-depth, including preparation procedures (carbonization and activation), sorption possible mechanisms, and physiochemical properties. Challenges and perspective for designing efficient and environmental benign biochar-based adsorbents are finally addressed.

Graphene (GR) and graphene oxide (GO) are widely being used as promising candidates for biomedical applications, as well as for bio-sensing, drug delivery, and anticancer therapy. However, their undesirable side effects make it necessary to assess further the toxicity and safety of using these materials. The main objective of the current study was to investigate the toxicities of GR and GO in predicted environmental relevant concentrations in adult zebrafish (Danio rerio), particularly on their behaviors, and conducted biochemical assays to elucidate the possible mechanism that underlies their toxicities. Zebrafish was chronically (∼14 days) exposed to two different doses of GR (0.1 and 0.5 ppm) or GO (0.1 and 1 ppm). At 14 ± 1 days, a battery of behavioral tests was conducted, followed by enzyme-linked immunosorbent assays (ELISA) test on the following day to inspect the alterations in antioxidant activity, oxidative stress, and neurotransmitters in the treated zebrafish brain. An alteration in predator avoidance behavior was observed in all treated groups, while GR-treated fish exhibited abnormal exploratory behavior. Furthermore, altered locomotor activity was displayed by most of the treated groups, except for the high concentration of the GR group. From the ELISA results, we discovered a high concentration of GR exposure significantly decreased several neurotransmitters and cortisol levels. Meanwhile, elevated reactive oxygen species (ROS) were displayed by the group treated with low and high doses of GR and GO, respectively. These significant changes would possibly affect zebrafish behaviors and might suggest the potential toxicity from GR and GO exposures. To sum up, the present study presented new evidence for the effects of GR and GO in zebrafish behavioral dysregulation. We hope these assessments can contribute to our understanding of graphene and graphene oxide biosafety.

The hazardous effects of herbicides are well known; however, their effects on the reproductive system remain unclear. In this study, we demonstrated the anti-proliferative effects of dinitramine (DN) on immature murine testicular cell lines (Leydig and Sertoli cells) mediated via endoplasmic reticulum (ER) stress-induced calcium dysregulation in the cytosol and mitochondria. The results demonstrated that the viability and proliferation of DN-treated TM3 and TM4 cells decreased significantly, even in the spheroid state. DN induced the apoptosis of TM3 and TM4 cells and decreased the expression of genes related to cell cycle progression. Treatment with DN increased the cytosolic and intramitochondrial levels of calcium by activating ER stress signals. DN activated the Erk/P38/Jnk Mapk pathway and inactivated the Pi3k/Akt pathway in murine testicular cells. Co-treatment with 2-aminoethoxydiphenyl borate (2-APB) mitigated DN-induced calcium upregulation in both testicular cell lines. Although 2-APB did not antagonize the anti-proliferative effect of DN in TM3 cells, treatment with 2-APB and 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid restored the proliferation of DN-treated TM4 cells.

Biochar amendment has the potential to reduce methylmercury (MeHg) uptake by rice grains in soil-rice ecosystem. Considering that sulfur can strongly bind Hg and thus reduce its bioavailability, S-modified biochar has been used to immobilize Hg in soils. However, whether natural S-enriched biochar can further reduce Hg and MeHg phytoavailability remains unknown. Moreover, the rhizosphere is one of the most important microbial hotspots regulating the pollutant dynamics in terrestrial ecosystems. Therefore, it is of greater practical significance to examine the impact of biochar amendment on MeHg production and phytoavailability in the rhizosphere versus nonrhizosphere. Here, by conducting a pot experiment, we evaluated the efficacy of biochar derived from sulfur-enriched oilseed rape straw to reduce MeHg accumulation in rice. The results demonstrated that: (1) biochar-induced enhancement of chloride ion and sulfate levels in the overlying water and pore water facilitate microbial methylation of Hg and thus MeHg production in rhizosphere soil. (2) biochar amendment increased rhizosphere soil sulfur content and humic acid-like substances, strengthening MeHg binding to soil, and thus reducing grain MeHg levels by 47%–75%. Our results highlight the necessity to applying natural sulfur-rich biochar accompanied with exogenous sulfur to further reduce MeHg phytoavailability.

The Clean Air Action implemented by the Chinese government in 2013 has greatly improved air quality in the North China Plain (NCP). In this work, we report changes in the chemical components of atmospheric fine particulate matter (PM₂.₅) at four NCP sampling sites from 2012/2013 to 2017 to investigate the impacts and drivers of the Clean Air Action on aerosol chemistry, especially for secondary inorganic aerosols (SIA). During the observation period, the concentrations of PM₂.₅ and its chemical components (especially SIA, organic carbon (OC), and elemental carbon (EC)) and the frequency of polluted days (daily PM₂.₅ concentration ≥ 75 μg m⁻³) in the NCP, declined significantly at all four sites. Asynchronized reduction in SIA components (large decreases in SO₄²⁻ with stable or even increased NO₃⁻ and NH₄⁺) was observed in urban Beijing, revealing a shift of the primary form of SIA, which suggested the fractions of NO₃⁻ increased more rapidly than SO₄²⁻ during PM₂.₅ pollution episodes, especially in 2016 and 2017. In addition, unexpected increases in the sulfur oxidation ratio (SOR) and the nitrogen oxidation ratio (NOR) were observed among sites and across years in the substantially decreased PM₂.₅ levels. They were largely determined by secondary aerosol precursors (i.e. decreased SO₂ and NO₂), photochemical oxidants (e.g. increased O₃), temperature, and relative humidity via gas-phase and heterogeneous reactions. Our results not only highlight the effectiveness of the Action Plan for improving air quality in the NCP, but also suggest an increasing importance of SIA in determining PM₂.₅ concentration and composition.