Phthalates (PAEs) are extensively used as plasticizers and constitute one of the most frequently detected organic contaminants in the environment. With the deterioration of eco-environment in China ...during the past three decades, many studies on PAE occurrence in soils and their risk assessments have been conducted which allow us to carry out a fairly comprehensive assessment of soil PAE contamination on a nation-wide scale. This review combines the updated information available associated with PAE current levels, distribution patterns (including urban soil, rural or agricultural soil, seasonal and vertical variations), potential sources, and human health exposure. The levels of PAEs in soils of China are generally at the high end of the global range, and higher than the grade II limits of the Environmental Quality Standard for soil in China. The most abundant compounds, di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP), display obvious spatial distribution in different provinces. It is noted that urbanization and industrialization, application of plastic film (especially plastic film mulching in agricultural soil) and fertilizer are the major sources of PAEs in soil. Uptake of PAEs by crops, and human exposure to PAEs via ingestion of soil and vegetables are reviewed, with scientific gaps highlighted.
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•PAE levels in soils of China were generally higher than the other countries.•DBP and DEHP are the dominant compounds in soil with obvious spatial distribution.•Urbanization and industrialization, application of plastic film and fertilizer are the major sources of PAEs in soil.•Uptake of PAEs by crops and human exposure to PAEs are reviewed.
Soil pollution with organic contaminants is one of the most intractable environmental problems today, posing serious threats to humans and the environment. Innovative strategies for remediating ...organic-contaminated soils are critically needed. Phytoremediation, based on the synergistic actions of plants and their associated microorganisms, has been recognized as a powerful in situ approach to soil remediation. Suitable combinations of plants and their associated endophytes can improve plant growth and enhance the biodegradation of organic contaminants in the rhizosphere and/or endosphere, dramatically expediting the removal of organic pollutants from soils. However, for phytoremediation to become a more widely accepted and predictable alternative, a thorough understanding of plant–endophyte interactions is needed. Many studies have recently been conducted on the mechanisms of endophyte-assisted phytoremediation of organic contaminants in soils. In this review, we highlight the superiority of organic pollutant-degrading endophytes for practical applications in phytoremediation, summarize alternative strategies for improving phytoremediation, discuss the fundamental mechanisms of endophyte-assisted phytoremediation, and present updated information regarding the advances, challenges, and new directions in the field of endophyte-assisted phytoremediation technology.
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•Endophytes are valuable bio-resources for enhancing phytoremediation efficiency.•The superiority of endophyte-assisted phytoremediation is assessed.•Mechanisms adopted by plant and endophyte for xenobiotic removal are summarized.•Cometabolism of plant and endophyte serves a main route for xenobiotic degradation.•“Omcs” techniques open up new perspectives for plant-endophyte interactions.
People spend most of their lives in buildings and unavoidably perceive the sound in their surroundings. The understanding of the human perceptual dimensions of sound is important for obtaining the ...occupant-oriented decision-making in future building designs. This paper presented a systematic review of the studies analyzing the human perceptual dimensions of sound. Studies that used of principal component analysis (PCA) or factor analysis (FA) for the semantic differential method (SDM) applications of the subjective measurements of the human perceptions of sound were identified in the study selection process and included in the quantitative analysis. Forty-five eligible studies covered a wide range of sounds in the general indoor environment, including machines, building facilities, human voices, human activities, transportations, and the urban environment. The meta-analysis of the factor analysis integrated the data from the 39 individual studies and generated the evidence-based results of the review. Three major perceptual dimensions of sound were found to be ”Evaluation,” ”Potency,” and ”Activity” which referred to the human general judgment, the sensitivity to the magnitude, and the sensation of the temporal and spectral compositions of the perceived sound respectively. It implied that not only the energy level but also the energy distribution of the stimulations in the environment affects our perceptions. The review also provided insights into the selection of the suitable perceptions, the suggestions on the SDM applications, and the acoustics index development for the quantification of the psychological impacts of sound on the occupants in the indoor and outdoor environment. This research provides directions for future psychoacoustics studies to analyze the correlations between the objective stimulations and the human perceptions.
•Computation of human perceptual dimensions of sound from the meta-analysis.•Understanding human interaction with the environment for building acoustics.•Directions of measurements in both objective and subjective assessments.•Verification of quantitative measurements of subjects' response.•Suggestions to the use of semantic deferential method in psychoacoustics studies.
Frequent cyanobacterial blooms in the eutrophic waters produce a variety of toxins such as the monocyclic heptapeptide microcystins, greatly harming aquatic ecosystems and human health. However, ...little information of microcystins in agricultural fields is known. This field study of three common microcystin variants (MC-LR, MC-RR, and MC-YR) in vegetables (n = 161), soils (n = 161) and irrigation water samples (n = 23) collected from southern China regions affected by cyanobacteria blooms, shows their prevalence with total concentrations up to 514 μg/L water, 187 μg/kg soil (dry weight) and 382 μg/kg vegetable (fresh weight). MC-RR was the primary variant in all types of samples, accounting for 51.3–100% of total microcystin concentrations. Significant concentration-dependent correlations (p < 0.05) demonstrated that microcystin-contained irrigation waters were the major source of microcystin accumulation in both vegetables and soils. Meanwhile, intracellular-microcystins in irrigation water was found to play an important role in microcystins bioaccumulation in vegetables for the first time. Most vegetable samples (≥60%), particularly celery posed moderate or high human health risk via diet based on toxicity equivalents of the microcystins and reference dose for MC-LR (0.04 μg/kg/d), showing high food safety hidden dangers. Soil microcystins, especially MC-RR in 46.4–88.3% of soils could pose high ecological risks. This study highlights the potential high ecological and human health risks of microcystins in the real soil-vegetable systems of areas affected by cyanobacteria blooms, implying the profound significance and urgent need of investigation on microcystins in terrestrial ecosystems.
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•MCs are prevalent in actual soil-crop systems affected by cyanobacterial blooms.•MC-RR was the primary variant in all types of the samples.•Intracellular-MCs could play an important role in vegetable MCs accumulation.•Most vegetable samples posed moderate or high human health risk via diet.•Soil MCs, especially MC-RR could pose high ecological risks.
With cancer survival rate climbing up over the past three decades, quality of life for cancer patients has become an issue of major concern. Oral health plays an important part in one’s overall ...quality of life. However, oral health status can be severely hampered by side effects of cancer therapies including surgery, chemotherapy, radiotherapy, and hematopoietic stem cell transplantation. Moreover, prevention and treatment of these complications are often overlooked in clinical practice. The present paper aims at drawing health care professionals’ attention to oral complications associated with cancer therapy by giving a comprehensive review. Brief comments on contemporary cancer therapies will be given first, followed by detailed description of oral complications associated with cancer therapy. Finally, a summary of preventive strategies and treatment options for common oral complications including oral mucositis, oral infections, xerostomia, and dysgeusia will be given.
Aim
Up‐to‐date epidemiological studies on the global burden of severe periodontitis is scarce. This study aimed to present the latest estimates for prevalence of severe periodontitis from 1990 to ...2019, by region, age, and level of socio‐demographic development.
Materials and Methods
Estimates from the Global Burden of Disease study 2019 were used to investigate burden and trends of prevalence of severe periodontitis and its association with socio‐demographic development at global, regional, and national level. Decomposition analysis was performed to explore the contribution of demographic and epidemiological factors to the evolving burden of severe periodontitis.
Results
In 2019, there were 1.1 billion (95% uncertainty interval: 0.8–1.4 billion) prevalent cases of severe periodontitis globally. From 1990 to 2019, age‐standardized prevalence rate of severe periodontitis increased by 8.44% (6.62%–10.59%) worldwide. Prevalence of severe periodontitis is higher among less developed countries/regions. Global population growth accounted for 67.9% of the increase in the number of prevalent cases of severe periodontitis from 1990 to 2019.
Conclusions
The global burden of severe periodontitis has been substantial and increasing over the past three decades. Upstream policy changes are urgently needed to address the global public health challenge of severe periodontitis.
Ciprofloxacin is a broad spectral and highly refractory antibiotic. It is an emerging pollutant. This study aimed to utilise co-metabolism as a means to degrade ciprofloxacin by a bacterial ...consortium. The stable bacterial consortium XG capable of efficiently degrading ciprofloxacin was successfully established through successive acclimation of indigenous microorganisms. The consortium XG was primarily consisted of Achromobacter, Bacillus, Lactococcus, Ochrobactrum, and Enterococcus as well as at least other five minor genera. A novel strain YJ17 with CIP-degrading ability was isolated from the consortium and identified as Ochrobactrum sp. The consortium XG utilised amino acids, carbohydrates, and carboxylic acids at a rate approximately 16.6–243-fold greater than the other carbon substrates, but only slow utilisation of ciprofloxacin as a sole carbon source. Ciprofloxacin can be co-metabolized along with many carbon sources, attaining degradation rates up to 63%. Glycyl-l-glutamic acid, d-cellobiose, and itaconic acid are among the substrates most favourable for co-metabolism. The metabolites of ciprofloxacin were identified by LC-QTOF-MS. Co-metabolic degradation of ciprofloxacin by consortium XG led to the removal of essential functional groups from parent compound, thus resulting in formation of metabolites with less bioactive potency. Finally, a possible biochemical pathway for the degradation of ciprofloxacin was proposed. Consortium XG possesses high potential for bioremediation of ciprofloxacin-contaminated environments in the presence of a co-substrate.
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•A novel bacterial consortium XG efficiently degrades ciprofloxacin (CIP).•Consortium XG comprises >10 bacterial genera.•Co-metabolism enhances ciprofloxacin biodegradation by consortium XG.•The substrates most favourable for CIP co-metabolism are obtained by consortium XG.
A novel bacterial strain designated as Rhodococcus pyridinivorans XB, capable of utilizing various endocrine disruptor phthalates or phthalic acid (PA) as sole source of carbon and energy, was ...isolated from activated sludge. Under the optimal culture conditions (pH 7.08, 30.4 °C, inoculum size (OD600 nm) of 0.6) obtained by response surface methodology, di-(2-ethylhexyl) phthalate (DEHP, 200 mg/L) could be degraded by strain XB with a removal rate of 98% within 48 h. Under the observation of an atomic force microscope, it was confirmed that DEHP did not inhibit the growth of strain XB which might produce some extracellular polymeric substances as a response to DEHP stress, resulting in rapid degradation of DEHP. At initial concentrations of 50–800 mg/L DEHP, its degradation curves were well fitted with the first-order kinetic model, and the half-life of DEHP degradation varied from 5.44 to 23.5 h. The degradation intermediates of DEHP were identified by both GC–MS and high performance liquid chromatography–time of flight-mass spectrometry (HPLC–TOF-MS). Significant up-regulation was observed for the relative expression levels of genes (i.e., phthalate hydrolase, PA 3,4-dioxygenase, protocatechuate 3,4-α and 3,4-β dioxygenase) involved in DEHP degradation determined by real-time quantitative PCR (RT-qPCR). A DEHP biodegradation pathway by strain XB was proposed based on the identified intermediates and the degrading genes. Bioaugmentation of DEHP-contaminated soils with strain XB could efficiently promote DEHP removal, offering great potential in bioremediation of DEHP-contaminated environment.
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•A novel Rhodococcus pyridinivorans XB capable of degrading DEHP was isolated.•Observation by atomic force microscope confirmed well growth of strain XB under DEHP stress.•DEHP metabolites with dioxygenase genes revealed its complete degradation pathway.•Bioaugmentation of this strain can enhance DEHP removal from contaminated soils.
A newly isolated strain Agromyces sp. MT-O could utilize various phthalates and efficiently degraded di-(2-ethylhexyl) phthalate (DEHP). Response surface methodology was successfully employed for the ...optimization of culture conditions including pH (7.2), temperature (29.6), and inoculum size (OD600 of 0.2), resulting in almost complete degradation of DEHP (200mgL−1) within 7days. At different initial concentrations (50–1000mgL−1), DEHP degradation curves were fitted well with the first-order kinetic model, and the half-life of DEHP degradation ranged from 0.83 to 2.92days. Meanwhile, the substrate inhibition model was used to describe the special degradation rate with qmax, Ks, and Ki of 0.6298day−1, 86.78mgL−1, and 714.3mgL−1, respectively. The GC–MS analysis indicated that DEHP was degraded into mono-ethylhexyl phthalate and phthalate acid before its complete mineralization. Bioaugmentation of DEHP-contaminated soils with strain MT-O has greatly enhanced DEHP disappearance rate in soils, providing great potential for efficiently remediating DEHP-contaminated environment.
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•This report is the first on DEHP-degradation bacteria from a novel genus Agromyces.•It used various PAEs as growth substrates and degraded DEHP at high concentrations.•The bacterium harbors the metabolic pathway for complete degradation of DEHP.•This strain can greatly enhanced the remove rate of DEHP in contaminated soils.
The growing incidence of microcystins (MCs) in the environment has become an issue of global concern for the high ecological and human health risks. Herein, a comparative adsorption of three MCs ...(MC-LR, MC-YR and MC-RR) by spent mushroom substrate (SMS)-derived biochars from contrasting pyrolytic conditions (temperature: 600/300 °C; and gas steam: CO2/N2) was surveyed to better understand the mechanisms and factors affecting the adsorption performance. For biochar preparation, 600 °C and CO2 led to greater levels of aromaticity, ash, SBET, and porosity, while 300 °C and N2 created more surface functional groups. The adsorption of MCs by biochars was a pH-dependent and endothermic physisorption process, following the pseudo-second-order kinetics (R2 = 0.99) and linear isotherm model (R2 > 0.88). The distribution coefficients Kd (0.98–19.2 L/kg) varied greatly among MCs (MC-YR > MC-RR > MC-LR) and biochars (BC600 > BN600 > BC300 > BN300), which depends on the combined effects of hydrophobicity, electrostatic attraction, H-bonding, cation bridging, and the amounts of adsorption sites on biochars. Higher ash, SBET, and total pore volume of BC600 facilitated the adsorption capacity for MCs relative to other biochars. Furthermore, the co-adsorption efficacy for MCs (Kd = 1.09–8.86 L/kg) was far below those for the single adsorption, indicating strong conflicts among competing MCs. This study sheds light on the roles of pyrolytic temperature and gas steam in biochar properties, and elucidates the mechanisms and factors affecting the adsorption performance of different MCs, which lays a foundation for MCs removal from water.
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•Higher peak temperature (PT) and CO2 better form biochar structure than did lower PT and N2.•Microcystin adsorption by biochars is a pH-dependent and endothermic physisorption.•MC-YR shows the highest affinity to biochars, followed by MC-RR and MC-LR.•SBET and pore volume are more vital for microcystin adsorption than surface function groups.
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