Effects of Various Carbon Nanotubes on Soil Bacterial Community Composition and Structure

Nanosized plastics (nanoplastics) releasing into the wastewater may pose a potential threat to biological nitrogen removal. Constructed wetland (CW), a wastewater treatment or shore buffer system, is an important sink of nanoplastics, while it is unclear how nitrogen removal in CWs occurs in response to nanoplastics. Here, we investigated the effects of polystyrene (PS) nanoplastics (0, 10, and 1000 μg/L) on nitrogen removal for 180 days in CWs. The results revealed that total nitrogen removal efficiency decreased by 29.5–40.6%. We found that PS penetrated the cell membrane and destroyed both membrane integrity and reactive oxygen species balance. Furthermore, PS inhibited microbial activity in vivo, including enzyme (ammonia monooxygenase, nitrate reductase, and nitrite reductase) activities and electron transport system activity (ETSA). These adverse effects, accompanied by a decline in the relative abundance of nitrifiers (e.g., Nitrosomonas and Nitrospira) and denitrifiers (e.g., Thauera and Zoogloea), directly accounted for the strong deterioration observed in nitrogen removal. The decline in leaf and root activities decreased nitrogen uptake by plants, which is an important factor of deterioration in nitrogen removal. Overall, our results imply that the presence of nanoplastics in the aquatic environment is a hidden danger to the global nitrogen cycle and should receive more attention.

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“…Details of this analysis are described in the Supporting Information (Text S7). 33 2.6. Phytophysiology Parameters.…”

Section: Methodsmentioning

confidence: 99%

Nanoplastics Disturb Nitrogen Removal in Constructed Wetlands: Responses of Microbes and Macrophytes

Yang

Guo

et al. 2020

Environ. Sci. Technol.

169

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“…Soil bacteria, reflecting the quality and health of soil, are sensitive to environmental stress induced by contaminants . Both the soil bacterial community and enzyme activity play a key role in biological soil processes, such as pollutant degradation, nutrient cycling, or crop production. , Activities of urease, invertase, catalase, and acid phosphatase were considered as an important health indicator in previous studies; , therefore, these enzymes were selected in this study.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Impacts of Cu(OH)₂ Nanopesticide and Ionic Copper on the Soil Enzyme Activity and Bacterial Community

Zhang

Qian

et al. 2020

J. Agric. Food Chem.

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Nanopesticides are being introduced in agriculture, and the associated environmental risks and benefits must be carefully assessed before their widespread agricultural applications. We investigated the impacts of a commercial Cu(OH)2 nanopesticide formulation (NPF) at different agricultural application doses (e.g., 0.5, 5, and 50 mg of Cu kg–1) on enzyme activities and bacterial communities of loamy soil (organic matter content of 3.61%) over 21 days. Results were compared to its ionic analogue (i.e., CuSO4) and nano-Cu(OH)2, including both the commercial unformulated active ingredient of NPF (AI-NPF) and synthesized Cu(OH)2 nanorods (NR). There were negligible changes in the activity of acid phosphatase, regardless of exposure dose, whereas significant (p < 0.05) variations in activities of invertase, urease, and catalase were observed at a dose of 5 mg kg–1 or higher. Invertase activity decreased with an increasing bioavailable Cu concentration in soil under various treatments. In comparison to CuSO4, both Cu(OH)2 nanopesticide (i.e., NPF) and nano-Cu(OH)2 (i.e., AI-NPF and NR) caused a significant (p < 0.05) inhibition of urease activity, wherein a significant (p < 0.05) increase in the activity of catalase was observed, representing serious oxidative stress. Accordingly, NPF, AI-NPF, and NR differently affected soil bacterial abundance, diversity, and community compared to CuSO4, which could have resulted from the changes in the bioavailable Cu concentration as a result of the distinct nature of copper spiked (i.e., nano form versus salt). Moreover, minor differences in the soil enzyme activity and bacterial community were observed between NPF and AI-NPF, reflecting that the impact of the Cu(OH)2 nanopesticide was primarily attributed to the presence of nano-Cu(OH)2. In total, the impacts of nano-Cu(OH)2 on the soil bacterial community and enzyme activity tested in this study differed from CuSO4, shedding light on the environmental risks of the Cu(OH)2 nanopesticide in the long run.

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“…Second, the presence of other carbon sources such as lignin or glucose which induce ligninolytic enzymes increases its toxicity over the nematode model (~50-70% death). This effect is potentially explained due to the chemical and structural modifications in the MWCNTs observed, such as have been described to occur in microbial communities (Ge et al, 2016;Wu et al, 2019). However, we can no to explain why the medium supplemented with MWCNTs + glucose was more toxic to the worms than MWCNTs alone, but after fungi growth is effect was reverted as expected (Fig.…”

Section: Discussionmentioning

confidence: 63%

Ligninolytic activity of the Penicillium chrysogenum and Pleurotus ostreatus fungi involved in the biotransformation of synthetic multi-walled carbon nanotubes modify its toxicity

Juárez-Cisneros

Campos-Garcı́a

Díaz-Pérez

et al. 2021

PeerJ

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Multi-walled carbon nanotubes (MWCNTs) are of multidisciplinary scientific interest due to their exceptional physicochemical properties and a broad range of applications. However, they are considered potentially toxic nanoparticles when they accumulate in the environment. Given their ability to oxidize resistant polymers, mycorremediation with lignocellulolytic fungi are suggested as biological alternatives to the mineralization of MWCNTs. Hence, this study involves the ability of two fungi specie to MWCNTs biotransformation by laccase and peroxidases induction and evaluation in vivo of its toxicity using Caenorhabditis elegans worms as a model. Results showed that the fungi Penicillium chrysogenum and Pleurotus ostreatus were capable to grow on media with MWCNTs supplemented with glucose or lignin. Activities of lignin-peroxidase, manganese-peroxidase, and laccase in cultures of both fungi were induced by MWCNTs. Raman, FTIR spectroscopy, HR-TEM, and TGA analyses of the residue from the cultures of both fungi revealed structural modifications on the surface of MWCNTs and its amount diminished, correlating the MWCNTs structural modifications with the laccase-peroxidase activities in the fungal cultures. Results indicate that the degree of toxicity of MWCNTs on the C. elegans model was enhanced by the structure modification associated with the fungal ligninolytic activity. The toxic effect of MWCNTs on the in vivo model of worms reveals the increment of reactive oxygen species as a mechanism of toxicity. Findings indicate that the MWCNTs can be subject in nature to biotransformation processes such as the fungal metabolism, which contribute to modify their toxicity properties on susceptible organisms and contributing to environmental elimination.

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Effects of Various Carbon Nanotubes on Soil Bacterial Community Composition and Structure

Cited by 45 publications

References 72 publications

Nanoplastics Disturb Nitrogen Removal in Constructed Wetlands: Responses of Microbes and Macrophytes

Nanoplastics Disturb Nitrogen Removal in Constructed Wetlands: Responses of Microbes and Macrophytes

Assessing the Impacts of Cu(OH)₂ Nanopesticide and Ionic Copper on the Soil Enzyme Activity and Bacterial Community

Ligninolytic activity of the Penicillium chrysogenum and Pleurotus ostreatus fungi involved in the biotransformation of synthetic multi-walled carbon nanotubes modify its toxicity

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Effects of Various Carbon Nanotubes on Soil Bacterial Community Composition and Structure

Cited by 45 publications

References 72 publications

Nanoplastics Disturb Nitrogen Removal in Constructed Wetlands: Responses of Microbes and Macrophytes

Nanoplastics Disturb Nitrogen Removal in Constructed Wetlands: Responses of Microbes and Macrophytes

Assessing the Impacts of Cu(OH)2 Nanopesticide and Ionic Copper on the Soil Enzyme Activity and Bacterial Community

Ligninolytic activity of the Penicillium chrysogenum and Pleurotus ostreatus fungi involved in the biotransformation of synthetic multi-walled carbon nanotubes modify its toxicity

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Assessing the Impacts of Cu(OH)₂ Nanopesticide and Ionic Copper on the Soil Enzyme Activity and Bacterial Community