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The purpose of this study was to investigate the impact of long-term application of pig manure on the accumulation of heavy metals, antibiotics and ARGs in surface soil sampled from the Jiaxing long-term field experimental site with three manure treatments, N-PM (0 kg/ha/y, dw), L-PM (7720 kg/ha/y, dw), and H-PM (11,580 kg/ha/y, dw), in 2013 and 2014. The results showed that most serious metal pollution of Zn and Cu was recorded in all manured samples in both years, and their contents exceeded the soil quality standards. Among the three tetracyclines, chlortetracycline was the predominant antibiotic detected with a range of 3.04–98.03 μg·kg −1 in 2013 and 28.67–344.74 μg·kg −1 in 2014 after long-term pig manure application. Q-PCR results showed that the average accumulation of ribosomal protection protein genes ( tet M, tet O, tet Q and tet W) was lower than most of the efflux pump genes ( tet A and tet G). The abundance of tet and sul genes of those sites with manure application was significantly higher than that of sites without manure application in both years. Metagenomics analysis of ARGs revealed that the abundance of multidrug resistance genes was the most abundant subtype, followed by fluoroquinolone, bacitracin, sulfonamide and tetracycline. There was a positive correlation between the levels of ARGs; soil organic matter, antibiotics, Cu, As, and Zn levels in both years. These results may shed light on the mechanism underlining the effects of long-term manure application on the occurrence and dissemination of ARGs in surface soil. [ABSTRACT FROM AUTHOR]

A recyclable magnetic rape straw biochar (MRSB) catalyst was synthesized by a high value-added and energy-saving method using abandoned rape straw as the raw material. The MRSB catalyst showed high catalytic activity and recyclability for activating persulfate (PS) to degrade tetracycline hydrochloride (TC) in water. The Fe 3 O 4 in the MRSB greatly promoted the activation of PS. More importantly, the MRSB catalyst exhibited high catalytic performance over a wide pH range (2.99–11.01) for activating PS to degrade TC in water. Moreover, MRSB still had good catalytic activity for TC degradation after 8 recycling cycles and was easily separated by an external magnetic field for reuse. The electron spin resonance (ESR) analysis indicated that the generation of the sulfate radicals (SO 4 −), hydroxyl radicals (OH) and superoxide radicals (O 2 −) was greatly promoted in the MRSB/PS system. As a result, MRSB exhibited 13.24-fold higher reaction rate for activating PS than those of rape straw biochar (RSB). Both radical mechanism and non-radical mechanism existed in the MRSB/PS system, and SO 4 − and singlet oxygen (1O 2) played a determinative role. This study might give a new way to reuse abandoned rape straw and synthesize new recyclable catalysts for activating PS to degrade organic pollutants in water. Unlabelled Image • The magnetic rape straw biochar was successfully prepared by a facile synthesis way. • The catalyst exhibited high catalytic activity in a wide pH range. • The catalyst still has good stability and catalytic activity after 8 recycling cycles. • Both radical mechanism and non-radical mechanism existed in the MRSB/PS system, and SO 4 − and 1O 2 played a dominate role. [ABSTRACT FROM AUTHOR]

The depletion of phosphorus resources and the excess discharge of phosphorus into waste streams are contrasting problems. The key to solving both problems is to recover phosphorus from the waste streams. Current phosphorus recovery technologies require high phosphorus concentrations and lack the ability to separate toxic substances from recovered phosphorus products. Membrane separation processes such as nanofiltration, forward osmosis, and electrodialysis are examples of effective methods for solving some of these issues. In this paper, the mechanisms, performance, and influential factors affect phosphorus recovery from membrane separation are reviewed. Membrane fouling, energy consumption, and the selectivity of toxic substances in membrane separation processes were evaluated. This work will serve as a basis for future research and development of phosphorus recovery by membrane separation processes and as a response to the increasingly pressing issues of eutrophication and the growing depletion of phosphorus resources. Unlabelled Image • Membrane separation processes for P recovery are reviewed. • Performance on membrane fouling, energy consumption, and selectivity was evaluated. • Prospects of membrane separation processes for P recovery are presented. [ABSTRACT FROM AUTHOR]

Nanoparticle capping agents are critical for controlling the growth, oxidation state, and final particle size during aqueous synthesis. However, despite the known phytotoxicity of cetyltrimethylammonium bromide (CTAB) to plants, it is used to synthesize metal oxide nanoparticles of uniform size and with mesoporous structure. Among the few studies that have investigated how CTAB influences nanoparticle toxicity, CTAB has never been identified as the primary cause of nanoparticle toxicity in environmental systems; rather nanoparticle surface charge or morphology was identified as the driver of toxicity in environmentally relevant systems. In the current study, CTAB release from CTAB surface modified Cu 2 O nanoparticles (SM-Cu 2 O NPs) inhibited duckweed (Landoltia punctata) growth, even when administered at subtoxic Cu concentrations. Organic ligands, such as humic acid (HA) and ethylenediaminetetraacetic acid (EDTA), lessened growth inhibition associated with exposure to SM-Cu 2 O NPs, likely through electrostatic and hydrophobic interactions with CTAB. Such results highlight the need for a more holistic approach to nanoparticle surface modification and improved communication between toxicologists and synthetic chemists to develop green alternatives for nanoparticle synthesis. Surface modification of metal oxide nanoparticles with CTAB, applied to improve nanoparticle uniformity and performance under specific conditions, may induce environmental toxicity at sub-toxic metal concentrations. Unlabelled Image • Released CTAB surface coatings can induce negative growth response in plants. • Ligands can alter the magnitude of the negative growth response to CTAB. • Green nanoparticle formulation can mitigate nanoparticle effects in natural systems. [ABSTRACT FROM AUTHOR]