Hydroponic experiments were conducted to study the effects of microplastic particles of polystyrene (PS) and polytetrafluoroethylene (PTFE) on arsenic (As) content in leaves and roots of rice seedlings, and the changes in root vigor and physiological and biochemical indicators under single or combined PS and PTFE with As(III) treatment. Rice biomass decreased with increasing concentrations of PS, PTFE, and As(III) in the growth medium. The highest root (leaf) biomass decreases were 21.4% (10.2%), 25.4% (11.8%), and 26.2% (16.2%) with the addition of 0.2 g L⁻¹ PS, 0.2 g L⁻¹ PTFE, and 4 mg L⁻¹ As(III), respectively. Microplastic particles and As(III) inhibited biomass accumulation by inhibiting root activity and RuBisCO activity, respectively. The addition of As(III) and microplastic particles (PS or PTFE) inhibited photosynthesis through non-stomatal and stomatal factors, respectively; furthermore, net photosynthetic rate, chlorophyll fluorescence, and the Chl a content of rice were reduced with the addition of As(III) and microplastic particles (PS or PTFE). Microplastic particles and As(III) induced an oxidative burst in rice tissues through mechanical damage and destruction of the tertiary structure of antioxidant enzymes, respectively, thereby increasing O₂⁻ and H₂O₂ in roots and leaves, inducing lipid peroxidation, and destroying cell membranes. When PS and PTFE were added at 0.04 and 0.1 g L⁻¹, respectively, the negative effects of As(III) on rice were reduced. Treatment with 0.2 g L⁻¹ PS or PTFE, combined with As(III), had a higher impact on rice than the application of As(III) alone. PS and PTFE reduced As(III) uptake, and absorbed As decreased with the increasing concentration of microparticles. The underlying mechanisms for these effects may involve direct adsorption of As, competition between As and microplastic particles for adsorption sites on the root surface, and inhibition of root activity by microplastic particles.

Although the development of constructing oil-water separation materials is quick, the defects of using harmful regents, weak stability and single function still exist. Here, we report an effective and less-harmful system with poly-dimethylsiloxane (PDMS)/ZnO composite solution to fabricate robust superhydrophobic surfaces for oil-water separation and removal of organic pollutant. The obtained samples were characterized by a range of instruments. The water contact angle (WCA) of coated cotton was 155.6°, which attributed to the synergetic effect of low surface energy of PDMS and roughness of ZnO nanoparticles. The coated cotton was tolerant to mechanical damage, various corrosive solvents and temperature conditions. The emphasis of this study is the combination of superhydrophobicity and photocatalysis, resulting in multifunctional cotton with dual self-cleaning properties, outstanding oil-water separation ability and efficient water purification property. When utilized a simple laboratory facility, the cotton could separate water from oil-water mixture with a high efficiency (99.3%). Furthermore, the dyed water could be purified with coated cotton through photocatalysis under UV light and became colorless. Meanwhile, this mild and facile method could also be utilized to modify other porous substrates, such as PET, silk, non-woven and sponge. Therefore, the characteristics of environmental protection and easy operation make this cotton a desirable candidate for extensive applications in self-cleaning, oil-water separation and water purification.

Though the main toxic mechanisms of graphene oxide (GO) to algae have been accepted as the shading effect, oxidative stress and mechanical damage, the effect of algal characteristics on these three mechanisms of GO toxicity have seldom been taken into consideration. In this study, we investigated GO toxicity to green algae (Chlorella vulgaris, Scenedesmus obliquus, Chlamydomonas reinhardtii), cyanobacteria (Microcystis aeruginosa) and diatoms (Cyclotella sp.). The aim was to assess how the physiological characteristics of algae affect the toxicity of GO. Results showed that 10 mg/L of GO significantly inhibited the growth of all tested algal types, while S. obliquus and C. reinhardtii were found to be the most susceptible and tolerant species, respectively. Then, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the physiological characteristics of the assessed algae. The presence of locomotive organelles, along with smaller and more spherical cells, was more likely to alleviate the shading effect. Variations in cell wall composition led to different extents of mechanical damage as shown by Cyclotella sp. silica frustules and S. obliquus autosporine division being prone to damage. Meanwhile, growth inhibition and cell division were significantly correlated with the oxidative stress and membrane permeability, suggesting the latter two indicators can effectively signal GO toxicity to algae. The findings of this study provide novel insights into the toxicity of graphene materials in aquatic environments.

Plants of the order Brassicaceae have evolved a chemical defence against herbivory: the glucosinolate-myrosinase system. Mechanical damage to plant tissues, such as grazing, initiates the production of phenethyl isothiocyanate (PEITC), a compound toxic to invertebrates. Mechanical damage caused during biofumigation and the harvesting and washing of watercress presents routes for PEITC release into waterbodies, such as the chalk stream spawning sites of brown trout (Salmo trutta). This laboratory study exposed developing S. trutta embryos to PEITC at concentrations of 0.01, 0.1 and 1 μg/L. S. trutta exposed to 1 μg/L PEITC during embryonic development resulted in 100% mortality after four dose days. Exposure to 0.1 μg/L PEITC resulted in an approximate fourfold increase in mortality relative to the controls, while exposure to 0.01 μg/L PEITC had a negligible effect on embryo mortality. Embryos exposed to 0.1 μg/L PEITC showed a significant delay in hatching and produced alevins with significantly shorter total lengths, lighter body weights and an approximate threefold increase in spinal deformities relative to those exposed to the controls and 0.01 μg/L PEITC. The results of a motor activity assay demonstrate that alevins exposed to PEITC showed a significant decrease in swimming activity compared with control animals during periods of illumination. The increased mortality, teratogenic effects and impaired behaviour in S. trutta following embryonic exposure to relatively low concentrations of PEITC highlight a need to accurately quantify and monitor environmental levels of PEITC.