Triphenyl phosphate (TPHP) is an organophosphate ester (OPE) used as a flame retardant (FR) and plasticizer. TPHP has previously been shown to disrupt behaviour in fish and mammals, but to our knowledge, this is the first study on the behavioural effects of TPHP in birds. Early life stage Japanese quail (Coturnix japonica) were exposed to nominal doses of 0 ng/g (vehicle-control), 5 ng/g (low dose), 50 ng/g (mid dose), and 100 ng/g (high dose) TPHP, both as embryos (via air cell injection prior to incubation) and as chicks (via daily gavage until 5 days post-hatch). The low dose reflects TPHP levels recorded in wild avian eggs, but actual environmental exposure levels may be higher given that TPHP is known to be rapidly metabolized in birds. We previously reported that the chicks exposed to TPHP in this study experienced reduced growth and resting metabolic rate, and sex-specific changes in thyroid function. The current study focuses on behavioural endpoints. We found that high-TPHP chicks exhibited less neophobia than vehicle-controls, and low-TPHP chicks exhibited more aggression towards conspecifics. No differences were observed in the responses of Japanese quail chicks to activity or tonic immobility (fear response) tests. These data add weight of evidence to previous findings suggesting that TPHP, among other OPEs, can disrupt ecologically-relevant behaviours in exposed vertebrates.

Nanoplastics are inevitably released into aquatic environments due to their extensive use and the continuous fragmentation of plastics. Therefore, it is imperative to understand the aggregation behaviours that determine the transport and fate of nanoplastics in aquatic environments. In this study, the effects of various metal cations, pH, aging and extracellular polymeric substances (EPS) on the aggregation of polystyrene nanoplastics (nano-PS) in aqueous solutions were systematically evaluated based on aggregation kinetics experiments and Derjaguin–Landau–Verwey–Overbeek (DLVO) theoretical calculation. The concentration, valence and hydration ability of metal cations jointly affected the aggregation of nano-PS. The critical coagulation concentration (CCC) of nano-PS was significantly higher than the ionic strengths in aquatic environments, indicating that the aggregation rate of nano-PS is relatively low in aquatic environments. The results of the aggregation kinetics experiments were consistent with DLVO theory, which showed that the energy barrier of nano-PS was dependent on electrostatic repulsion forces and van der Waals forces, and increased with pH. Nano-PS was artificially aged by UV-H₂O₂, which reduced the hydrophobic nature of the particle surfaces, consequently enhancing the stability of the nanoplastics. EPS (excreted from Chlorella pyrenoidosa) decreased the aggregation rates of nano-PS due to steric effects, which was confirmed by the extend DLVO model. Our results highlight the high stability of nano-PS in aquatic environments, which could help facilitate the evaluation of their environmental impact.

Silver nanoparticles (AgNP) are commonly used in medical, cosmetics, clothing, and industrial applications for their antibacterial and catalytic properties. As AgNP become more prevalent, the doses to which humans are exposed may increase and pose health risks, particularly through incidental inhalation. This exposure was evaluated through in-vitro methods simulating lung fluids and lung epithelium, and through computational fluid dynamics (CFD) methods of AgNP transport. A high-dose scenario simulated a short-term inhalation of 10 μg AgNP/m³, based on an exposure limit recommended by the National Institute of Occupational Safety and Health for the case of a health-care worker who handles AgNP-infused wound dressings, and regularly wears AgNP-imbedded clothing. Bioaccessibility tests were followed by a Parallel Artificial Membrane Permeability Assay (PAMPA) and supported by CFD models of the lung alveoli, membrane, pores, and blood capillaries. Results indicate that such exposure produces an average and maximum AgNP flux of approximately 4.7 × 10⁻²¹ and 6.5 × 10⁻¹⁹ mol m⁻²·s⁻¹ through lung tissue, respectively, yielding a blood-silver accumulation of 0.46–64 mg per year, which may exceed the lowest adverse effect level of 25 mg for an adult male. Results from in-silico simulations were consistent with values estimated in vitro (within an order of magnitude), which suggest that CFD models may be used effectively to predict silver exposure from inhaled AgNP. Although the average short-term exposure concentrations are 3 orders of magnitude smaller than the reported threshold for mammalian cytotoxicity effects (observed at 5000 ppb), cumulative effects resulting from constant exposure to AgNP may pose risks to human health in the long-term, with predicted bioaccumulation reaching potential toxic effects after only five months of exposure, based on maximum flux.

Nitrogen (N) deposition has been conventionally thought to decrease forest soil methane (CH₄) uptake, while the biome specific and dose dependent effect is poorly understood. Based on a meta-analysis of 63 N addition trials from 7 boreal forests, 8 temperate forests, 13 subtropical and 4 tropical forests, we evaluated the effects of N addition on soil CH₄ uptake fluxes across global forest biomes. When combining all N addition levels, soil CH₄ uptake was insignificantly decreased by 7% in boreal forests, while N addition significantly decreased soil CH₄ uptake by 39% in temperate forests and by 21% in subtropical and tropical forests, respectively. Meta-regression analyses, however, indicated a shift from a positive to a negative effect on soil CH₄ uptake with increasing N additions both in boreal forests (threshold = 48 kg N ha⁻¹ yr⁻¹) and temperate forests (threshold = 27 kg N ha⁻¹ yr⁻¹), while no such shift was found in subtropical and tropical forests. Considering that current N deposition to most boreal and temperate forests is below the abovementioned thresholds, N deposition likely exerts a positive to neutral effect on soil CH₄ uptake in both forest biomes. Our results provide new insights on the biome specific and dose dependent effect of N addition on soil CH₄ sink in global forests and suggest that the current understanding that N deposition decreases forest soil CH₄ uptake is flawed by high levels of experimental N addition.

Understanding the composition and assembly mechanism of waterborne pathogen is essential for preventing the pathogenic infection and protecting the human health. Here, based on 16S rRNA sequencing, we investigated the composition and spatial variation of potentially pathogenic bacteria from different sections of the Pearl River, the most important source of water for human in Southern China. The results showed that the potential pathogen communities consisted of 6 phyla and 64 genera, covering 11 categories of potential pathogens mainly involving animal parasites or symbionts (AniP), human pathogens all (HumPA), and intracellular parasites (IntCelP). Proteobacteria (75.87%) and Chlamydiae (20.56%) were dominant at the phylum level, and Acinetobacter (35.01%) and Roseomonas (8.24%) were dominant at the genus level. Multivariate analysis showed that the potential pathogenic bacterial community was significantly different among the four sections in the Pearl River. Both physicochemical factors (e.g., NO₃–N, and suspended solids) and land use (e.g., urban land and forest) significantly shaped the pathogen community structure. However, spatial effects contributed more to the variation of pathogen community based on variation partitioning and path analysis. Null model based normalized stochasticity ratio analysis further indicated that the stochastic process rather than deterministic process dominated the assembly mechanisms by controlling the spatial patterns of potential pathogens. In conclusion, high-throughput sequencing shows great potential for monitoring the potential pathogens, and provided more comprehensive information on the potentially pathogenic community. Our study highlighted the importance of considering the influences of dispersal-related processes in future risk assessments for the prevention and control of pathogenic bacteria.

Environmental chemical exposures have been implicated as risk factors for the development of non-alcoholic fatty liver (NAFLD). Bisphenol S (BPS), widely used in multitudinous consumer products, could disrupt lipid metabolism in the liver. This study aimed at examining the hypothesis that long-term exposure to BPS promotes the development of liver fibrosis and inflammation by means of the application of a semi-static exposure experiment that exposed zebrafish to 1, 10, and 100 μg/L BPS from 3 h post fertilization to 120 day post fertilization. Results showed that the 120-d BPS exposure elevated plasma aspartate aminotransferase and alanine aminotransferase activities, increased triacylglycerol (TAG) and total cholesterol levels in male liver, and even induced hepatic apoptosis and fibrosis. Hepatic lipid accumulation observed in the 30-d BPS-exposed zebrafish was recovered after a 90-d depuration phase, thereby indicating that long-term BPS exposure promotes the progression of simple steatosis to non-alcoholic steatohepatitis. Furthermore, BPS exposure for 120-d promoted the synthesis of TAG and lipotoxic free fatty acids by elevating the transcription of srebp1, acc, fasn, and elovl6, induced endoplasmic reticulum (ER) stress with increasing expression levels of unfolded protein response (UPR) genes (perk, hsp5, atf4a, and ddit3), and then stimulated the expression of two key autophagy genes (atg3 and lc3) and inflammatory genes (il1b and tnfα). It is indicated that BPS can induce the development of steatohepatitis via the activation of the PERK-ATF4a pathway of the UPR. Data gathered suggest that environmental pollutants-induced ER stress with the activation of UPR can potentially trigger the NAFLD development in males. Overall, our study provided new sights into understanding of the adverse health effects of metabolism disrupting chemicals.

Plastics are crucial for our modern lifestyle and yet pose a major threat to our environment. Rising levels of microplastics (MP) in rivers and oceans are a big challenge for our economy and regulatory institutions as well as from a scientific point of view. Smaller microplastic particles, in particular, are especially hard to identify and even harder to quantify in environmental samples. Hence, we present a novel and inexpensive approach to quantify microplastics (MP) on a weight basis, relying on a thermoanalytical method. The Elemental Analysis combined with Overdetermined Equation Method (EA-OEM) was originally developed for determining the plastic content of refuse-derived fuels. It makes use of the distinct differences in the organic elemental composition (C, H, N, S, O) of plastics, biogenic and inorganic materials to calculate the (micro)plastic content on a detailed weight base. The study presented provides the first experimental results yielded from the application of the EA-OEM and two different laboratory approaches to the analysis of polyethylene (PE) and polypropylene (PP) MP content in industrial effluent samples from one source. In this way, it was possible to ensure that the polymer composition was known and the MP content therein (10–29%) could be derived. Further, the study reveals good MP recovery rates when applying the methodology to PE/PP-spiked samples.

The increasing prevalence and spread of antibiotic resistance genes (ARGs) in intensive aquaculture environments are of great concern to food safety and public health. However, the level of ARGs and their potential propagation factors in an industrial recirculating aquaculture system (RAS) have not previously been comprehensive explored. In this study, the levels of 14 different ARG markers and 2 kinds of mobile genetic elements (MGEs) were investigated in a RAS (including water, fish, feces, pellet feed meal, and biofilm samples) located northern China. qnrA, qnrB, qnrS, qepA, aac(6′)-Ib, and floR were dominant ARGs, which average concentration levels were presented at 4.51–7.74 copies/L and 5.36–13.07 copies/g, respectively, suggesting that ARGs were prevalent in RAS with no recorded history of antibiotic use. Elevated level of ARGs was found in water of RAS even after the final UV treatment compared with its influent. In RAS, Proteobacteria, Verrucomicrobia, Bacteroidetes, and Planctomycetes were the predominant phyla. Notably, elevated levels of potential opportunistic pathogens were observed along with abundant ARGs suggesting an increasing risk of capturing ARGs and MGEs for human pathogens. This study has revealed for the first time that reared fish, their feces, pellet feed meal as the introduction sources and the selection roles of treatment units co-driven the ARG profile, and the co-selection of water environmental factors and their consequently induced bacterial community shifts formed by their influence are the determining drivers for the ARG propagation in RAS.

The boreal forest’s pulp and paper industry plays a major role in economic prosperity but, historically, caused an environmental burden. Remnants of discharges of contaminated suspended solids (fiberbanks) are continuously being discovered on the beds of shallow seas, rivers and lakes in the northern hemisphere. We investigated the dispersion of Cd, Cr, Cu, Hg, Ni, Pb and Zn from deeper to surficial layers in fiberbanks in a Swedish estuary and the larger-scale transport of the same metals to distal areas of sediment accumulation. We also tested the C:N ratio as a common denominator for these anthropogenic, cellulose-rich deposits. Sampling and analyses of three fiberbanks located in the inner part of the estuary and from sediment accumulation sites outside and along the estuary reveals that metal concentrations are regressing to background levels towards the surface at the accumulation sites. The fiberbanks show a higher degree of contamination and C:N ratios demonstrate inclusion of cellulose fibers. C:N ratios also indicate that there is currently no significant transport of fiberbank material into the distal areas. A ∼10 cm natural cap of recently settled fine-grained sediment covering one of the fiberbanks seems to prevent metals dispersing into overlying water whereas the other two fiberbanks show signs of metal enrichment and potential mercury methylation in surficial layers. Although the estuarine system seems to recover from the impact of industrial waste, there is no evidence that the fiberbanks will be remediated naturally but instead will continue to threaten the aquatic environment.

The occurrence and composition profiles of 13 triester organophosphate flame retardants and their three diester metabolites in river water, wastewater, and tap water in China were studied. Most target organophosphate esters (OPEs) were found in water samples, with average concentrations of 787 ng/L for triethyl phosphate (TEP) and 0.1 ng/L for tripropyl phosphate (TPP) in wastewater, 1.48 × 10³ ng/L for TEP and 0.12 ng/L for tripentyl phosphate (TPeP) in river water, and 15.5 ng/L for tris(2-chloroethyl) phosphate (TCEP) and 0.08 ng/L for tritolyl phosphate (TMPP) in tap water. TEP was the most abundant compound among the detected OPEs in all water types. The exposure of zebrafish embryos showed negligible effects of TEP, triphenyl phosphate (TPHP), and diphenyl phosphate (DPHP), while mixed solutions that mimic river water and wastewater composition disturbed the development of embryos and led to the altered transcription of genes relating to the hypothalamic-pituitary-thyroid (HPT) axis. In addition, the binding affinity between OPEs and a thyroid hormone receptor (TRβ) protein was further investigated by molecular docking modeling, which helped to estimate the effects of OPEs on TRβ. This research provides experimental and theoretical evidence for the ecotoxicological effects of OPEs in aquatic environments.