论文检索

总访问量：4852936次

总访客量：242980人

所有论文

17601. 题目: Groundwater antibiotic pollution and its relationship with dissolved organic matter: Identification and environmental implications
文章编号: N21080911
期刊: Environmental Pollution
作者: Meritxell Gros, Núria Catalán, Josep Mas-Pla, Mira Čelić, Mira Petrović, Maria José Farré
更新时间: 2021-08-09
摘要: The occurrence of veterinary antibiotics and hydro-chemical parameters in eleven natural springs in a livestock production area is evaluated, jointly with the characterization of their DOM fingerprint by Orbitrap HRMS. Tetracycline and sulfonamide antibiotics were ubiquitous in all sites, and they were detected at low ng L−1 concentrations, except for doxycycline, that was present at μg L−1 in one location. DOM analysis revealed that most molecular formulas were CHO compounds (49%–68 %), with a remarkable percentage containing nitrogen and sulphur (16%–23 % and 11%–24 %, respectively). Major DOM components were phenolic and highly unsaturated compounds (∼90 %), typical for soil-derived organic matter; while approximately 11 % were unsaturated aliphatic, suggesting that springs may be susceptible to anthropogenic contamination sources. Comparing the DOM fingerprint among sites, the spring showing the most different profile was the one with surface water interaction and characterized by having lower CHO and higher CHOS formulas and aliphatic compounds. Correlations between antibiotics and DOM showed that tetracyclines positively correlate with unsaturated oxygen-rich substances, while sulfonamides relate with aliphatic and unsaturated oxygen-poor compounds. This indicates that the fate of different antibiotics will be controlled by the type of DOM present in groundwater.

17602. 题目: The sorption and short-term immobilization of lead and cadmium by nano-hydroxyapatite/biochar in aqueous solution and soil
文章编号: N21080910
期刊: Chemosphere
作者: Cailing Zhou, Xin Song, Yiwei Wang, Hui Wang, Shifu Ge
更新时间: 2021-08-09
摘要: In this study, the composite materials using different ratios of biochar (BC) to nano-hydroxyapatite (nHAP) were prepared for the remediation of lead (Pb) and cadmium (Cd) contaminated water and soil. The sorption and the immobilization experiments indicated a higher sorption capacity and immobilization efficiency of Pb compared to those of Cd. The characteristics of XRD, FTIR, SEM, and XPS manifested that dissolution-precipitation, cation exchange, complexation, and cation-π interaction were the main four mechanisms for the sorption of Pb2+ and Cd2+ using composite material PC1 (nHAP/BC = 1/1). From semi-quantitative analysis, the mineral effect accounted for the majority of the immobilization of Pb and Cd. Due to obvious Pb-precipitates in the sorbed material, dissolution-precipitation primarily affected the sorption of Pb and PC1, while the immobilization of Cd was mainly attributable to cation exchange. Such results corresponded to the stable Pb-precipitates and unstable Cd-compounds in soil, among which the latter was prone to be released into the environment. The sorption capacity in aqueous solutions and the immobilization efficiencies in the soil for both Pb and Cd increased with the addition of nHAP, which were linearly correlated to the nHAP proportion in the composite materials. In future practical applications, the percentages of composite materials can be designed according to the specific pollutant concentration. This study sheds light on the explicit immobilization mechanisms for Pb and Cd in aqueous solutions to better understand their behaviors in the soil remediated by relevant materials.

17603. 题目: Aboveground litter addition for five years changes the chemical composition of soil organic matter in a temperate deciduous forest
文章编号: N21080909
期刊: Soil Biology and Biochemistry
作者: Xin Wang, Weiwei Dai, Timothy R. Filley, Chao Wang, Edith Bai
更新时间: 2021-08-09
摘要: Global climate change has been found to affect plant net primary production and thereby could modify the quantity and quality of aboveground litter, which may consequently affect soil organic carbon (SOC). Whether those changes have influenced the chemical components of SOC is still unclear, especially for the soil beneath the surface soil. This study examined the changes in biopolymers (lignin, substituted fatty acids, amino sugars) in 0-10 cm and 10-20 cm soil depth in a temperate forest after five years of aboveground litter addition or removal treatments. The results showed that although SOC and nitrogen contents were not influenced by litter manipulation, the lignin phenols and substituted fatty acids contents in SOC of 10-20 cm soil were significantly higher in litter addition treatment compared to litter removal treatment, suggesting a selective accumulation pathway for these plant biopolymers in the 10-20 cm soil under litter manipulation. Soil amino sugar content, however, was not influenced by litter manipulation, although microbial biomass carbon (MBC) and nitrogen in 0-10 cm soil were significantly higher in litter addition plots due to the significantly higher substrate availability (dissolved organic carbon) and nutrient availability (total dissolved nitrogen) than those in the control. Although higher MBC could increase decomposition of SOC, this effect did not counterbalance the effect of higher aboveground litter input in litter addition plots, but rather changed the composition of SOC toward compounds of a purportedly more stable composition. The effects of aboveground litter removal were not entirely in contrast to the effects of aboveground litter addition on SOC, hinting that belowground inputs could sustain the storage of SOC for at least five years under aboveground litter removal treatment. The changes in the chemical composition of SOC under litter manipulation for five years suggested the potential changes in SOC stability and pool size in the future, especially in the 10-20 cm soil, to which more attention should be paid in future litter manipulation studies.

17604. 题目: Impact of palaeo-wildfires on higher plant parameter revealed by new biomarker indicator
文章编号: N21080908
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Adam Zakrzewski, Paweł Kosakowski
更新时间: 2021-08-09
摘要: Palaeo-wildfires were a common phenomenon in the Earth history. Their products can influence on some biomarker indicators characterising palaeo-environment conditions. Selected plant-derived aromatic biomarkers and polycyclic aromatic hydrocarbons (PAHs) were analysed in the Jurassic strata from the Polish Basin, Jurassic strata from the Mesozoic basement of the Carpathian Foredeep and Neogene strata from the Carpathian Foredeep. Marked compounds recorded varied input from palaeoflora families and the variable intensity of palaeo-wildfires. Retene (Ret), cadalene (Cad), 6-isopropyl-1-isohexyl-2-methylnaphthalene (ip-iHMN), dehydroabietic acid methyl ester (DAME), simonellite (Sim), fluoranthene (Fl), benz[α]anthracene (BaA), benzo[α]pyrene (BaP), benzo[ghi]perylene (BgP), coronene (Cor) were identified in the analysed samples. Based on mentioned compounds, pyrolytic input ratio (PIR) defined as (Cad + Sim + TDHA+ip-iHMN+Fl + BaA + BaP + BgP + Cor)/(Cad + Sim + TDHA+ip-iHMN) was proposed. To provide broader possibility of use, the total dehydroabietic acid (TDHA) counted as sum of DAME and free dehydroabietic acid was used in PIR equation. PIR manage to define pyrolytic organic matter input. Combination of PIR with higher plant parameter (HPP) results, defined as Ret/(Cad + Ret), enables the distinction of samples deposited in a warm/hot and humid palaeo-climate from these deposited in more arid conditions, which were affected by palaeo-wildfires. Heretofore, high HPP values have been interpreted as an evidence of a warm/hot and humid palaeo-climate. This interpretation is true when PIR values are low. If the PIR values were higher, then the palaeo-wildfires influence on HPP was more significant and palaeo-climate misinterpretation was more probably. The new indicator can be used in case of immature or early mature and mostly terrestrial organic matter.

17605. 题目: Mutually trading off biochar and biogas sectors for broadening biomethane applications: A comprehensive review
文章编号: N21080907
期刊: Journal of Cleaner Production
作者: Sameer Ahmad Khan, Tinku Casper D’ Silva, Subodh Kumar, Ram Chandra, Virendra Kumar Vijay, Ashish Misra
更新时间: 2021-08-09
摘要: The biogas sector has been in the limelight in renewable energy sources with its eco-friendly and carbon capturing characteristics for more than a century. Over the years, the sector has expanded into three major subsidiaries, namely, “biogas production,” “upgradation,” and “bottling and dissemination” for energy applications. This review emphasizes exploring the opportunities of the carbonaceous material “Biochar” on how it can play a crucial role in all the three subsidiaries imparting a positive advancement in the biogas sector. The contribution of different biochar properties in the biogas sector to negotiate the challenges faced explicitly for the biogas production, syntrophic microbial activity, and interspecies electron transfer, biomethane enrichment, and high-pressure bottling are extensively discussed from systematically selected literature. According to the study, the properties such as adsorption capacity, high pH, cation exchange capacity, electrical conductivity etc., enhanced the various subsidiaries of the biogas sector. Results suggest that the amendment of biochar in the biogas sector could unravel new opportunities in terms of biomethane applications. High-quality biochar is expected from the slow pyrolysis process from the lignin-rich substrate, while easily biodegradable substrate could be utilized for biogas production for mutual trade-offs between the sectors. Thus, a self-resource sufficient biochar-biogas closed-loop system can be developed to utilize waste biomasses efficiently. The techno-economics and sustainability of the proposed concept are also discussed. The study further gives a conclusive outlook on research gaps and future directions over the use of biochar for methane enhancement and enrichment from the biogas and its low-pressure storage.

17606. 题目: Enhancement of soil microstructural stability and alleviation of aluminium toxicity in acidic latosols via alkaline humic acid fertiliser amendment
文章编号: N21080906
期刊: Chemical Geology
作者: Aini Deng, Xiaofang Wu, Chulian Su, Min Zhao, Bin Wu, Jinhui Luo
更新时间: 2021-08-09
摘要: Alkaline humic acid fertiliser amendment (HAFA) can significantly enhance the microstructural stability of soils, as well as alleviate Al toxicity. Thus, the potential effects of HAFA on soil have attracted increased attention. A soil incubation experiment was conducted to evaluate the effects of HAFA. A typical acidic latosol was cultured for 51 days with five fertiliser treatments—unfertilised (CK), 0.32 g of inorganic fertiliser (IF), 0.32 g of inorganic fertiliser combined with 1.00 g lime (IF.CaO), 0.32 g of HAFA (HAFA0.32), and 0.42 g of HAFA (HAFA0.42)—to investigate the effects of HAFA on the microstructural stability and Al toxicity of soils. The results indicate that HAFA increased the number of aggregates and their honeycomb structures in latosol, as well as enhanced the adsorption capacity of the aggregates. HAFA not only increased latosol pH by 0.72–0.92, but also reduced the exchangeable acid content by 39.49–43.03% as compared with CK, which was similar to the lime treatment; it also significantly increased the soil organic matter content and the availability of N, P, and K, and improved the cation exchange capacity. However, HAFA decreased the effect of increasing the amount of exchangeable Ca when compared to the lime treatment. Additionally, the total amounts of reactive and exchangeable Al in the HAFA treatments were reduced by 45.84–54.59% and 56.67–67.53%, respectively. Both HAFA and lime applications effectively decreased the concentrations of phytotoxic Al species in latosols when compared to the application of inorganic fertiliser alone, with the HAFA0.42 treatment being more effective than lime application in decreasing the amount of dissolved and exchangeable Al. The HAFA0.42 treatment was also the best amendment for stabilising the microstructure, increasing the nutrient content, and mitigating Al toxicity in the potted acidic latosol.

17607. 题目: Use of either pumice or willow-based biochar amendments to decrease soil salinity under arid conditions
文章编号: N21080905
期刊: Environmental Technology & Innovation
作者: Chao Kong, Marta Camps-Arbestain, Brent Clothier, Peter Bishop, Felipe Macías Vázquez
更新时间: 2021-08-09
摘要: In order to alleviate salt- and water-stress in plants, innovative and economically-feasible techniques are needed. In this study, pumice and biochar (made from willow at 350 °C) of different particle sizes (1.5-, 3-, and 6-cm Ø) were separately added at different rates (3, 6, and 12%, v/v basis) to a sandy soil and their effects on soil salinity and water retention were evaluated over time. Soils were drip irrigated with an artificial saline water under non-draining conditions. Pebbles applied at identical rates and sizes as pumice and biochar, were used as positive controls, whereas no amendment was the negative control. Treatments underwent 10 wetting and drying cycles at 35 °C at the end of which, the residual sandy soil (RS) was separated from the amendments. The electrical conductivity (EC) of RS followed the order pumice < biochar < positive control = negative control, with differences being significant at P < 0.05. The smallest EC and sodium adsorption ratio (SAR) values of the RS were achieved when applying 12% pumice, regardless of the particle size; the opposite pattern (12% > 6% > 3%) was observed in the pumice when analysed separately from RS. Pumice and biochar treatments also retained more water in the soil after each drying cycle (significant at P < 0.05). At the end of the experiment, the EC values of the leachates indicated that salts retained in pumice were more slowly mobilised than those in the biochar. The application of either pumice or biochar (made from willow at 350 °C) can contribute to decrease soil salinity, but pumice could additionally serve as a tool to remove salts from salt-affected soils.

17608. 题目: Constraining bioavailable polyaromatic hydrocarbons effectively during the production and application of biochar
文章编号: N21080904
期刊: Environmental Technology & Innovation
作者: Lionel J Clarke
更新时间: 2021-08-09
摘要: Biochar has substantial potential as a globally significant negative emissions technology (NET) provided that it can be deployed economically at a sufficiently large scale without introducing unintended negative impacts. The generation of polyaromatic hydrocarbons (PAHs) during the production of biochars has been identified as a potential risk. A commonly applied risk management and certification mechanism is to set an upper limit on the total PAH loading of the produced biochar. However, this simple metric does not take into account the strong affinity for biochar to bind PAHs, which can significantly reduce their bioavailablity and associated potential risks to health and the environment. Nor does reflect the fact that not all PAHs are the same, and that the distribution of more and less toxic species within the total is influenced by a number of feedstock and production factors. The capacity for biochar to adsorb potential toxins, not only PAHs, but also heavy metals and other organic pollutants from contaminated soils and aqueous media is an important and affordable mechanism to help reduce the uptake of such pollutants and their associated risks to health. Elevated concentrations of PAHs are often to be found in soils located in the vicinity of roads, heavy industries and crop-burning activities. The addition of suitably prepared biochar in such situations can result in a net reduction in bioavailable PAHs. Whilst the imposition of tight constraints is justifiable for certain applications, such as when used as a ruminant feed supplement, adherence to excessively tight constraints in general may unintentionally inhibit the generation of biochar by more affordable processes that would otherwise be sufficient to deliver net environmentally positive benefits, local and global. By managing overall risk on a more class-by-class basis, the potential for large-scale deployment of biochar as a NET may be realised effectively and safely.

17609. 题目: Integrated glycolysis and pyrolysis process for multiple utilization and cadmium collection of hyperaccumulator Sedum alfredii
文章编号: N21080903
期刊: Journal of Hazardous Materials
作者: Xinyu Guo, Shijun Zhang, Jipeng Luo, Minghui Pan, Yilin Du, Yongchao Liang, Tingqiang Li
更新时间: 2021-08-09
摘要: Phytoremediation is a cost-effective and environmentally-friendly method to treat cadmium (Cd) contaminated soils, however, there is still a lack of safe disposal methods of harvested hyperaccumulators. In this study, by integrating glycolysis and pyrolysis, we investigated the possibility of bioproduct production and Cd collection from the hyperaccumulator Sedum alfredii. By means of acid-alkali pretreatment, the degree of cellulose polymerization was reduced by 36.24% while the surface accessibility was increased by 115.80%, resulting in a bioethanol yield of 9.29%. Meanwhile, 99.22% of total Cd of biomass could be reclaimed by collecting H2SO4-pretreatment waste. The saccharification residue was subsequently modified by NaOH-pretreatment-filtrate and converted into biochar at 500°C which possessed a maximum Cd2+ sorption capacity of 60.52mgg−1 based on the Langmuir model. Furthermore, sustainability analysis indicated that the economic input of this process is acceptable when considering its good environmental benefits. Taken together, our study provides a strategy for simultaneous bioethanol and biochar production during Cd collection from the hyperaccumulator S. alfredii, which could be a promising alternative for the suitable treatment of metal-enriched plants.

17610. 题目: The Influent COD/N Ratio Controlled the Linear Alkylbenzene Sulfonate Biodegradation and Extracellular Polymeric Substances Accumulation in an Oxygen-based Membrane Biofilm Reactor
文章编号: N21080902
期刊: Journal of Hazardous Materials
作者: Yun Zhou, Ran Li, Bing Guo, Siqing Xia, Yang Liu, Bruce E. Rittmann
更新时间: 2021-08-09
摘要: This work evaluated the fates of linear alkylbenzene sulfonate (LAS), chemical oxygen demand (COD), ammonia nitrogen (NH+ 4-N), and total nitrogen (TN) when treating greywater (GW) in an oxygen-based membrane biofilm reactor (O2-MBfR). An influent ratio of chemical oxygen demand to total nitrogen (COD/TN) of 20g COD/g N gave the best removals of LAS, COD, NH+ 4-N and TN, and it also had the greatest EPS accumulation in the biofilm. Higher EPS and improved performance were linked to increases in the relative abundances of bacteria able to biodegrade LAS (Zoogloea, Pseudomonas, Parvibaculum, Magnetospirillum and Mycobacterium) and to nitrify (Nitrosomonas and Nitrospira), as well as to ammonia oxidation related enzyme (ammonia monooxygenase). The EPS was dominated by protein, which played a key role in adsorbing LAS, achieving short-time protection from LAS toxicity and allowed LAS biodegradation. Continuous high-efficiency removal of LAS alleviated LAS toxicity to microbial physiological functions, including nitrification, nitrate respiration, the tricarboxylic acid (TCA) cycle, and adenosine triphosphate (ATP) production, achieving the stable high-efficient simultaneous removal of organics and nitrogen in the O2-MBfR.

17611. 题目: The fate of heavy metals in excess sludge during disintegration by discharge plasma
文章编号: N21080901
期刊: Separation and Purification Technology
作者: Tengfei Li, Yuxuan Zhang, Zhiyin Ren, Xiwen Cheng, Hu Li, Ying Zhang, Guangzhou Qu, Tiecheng Wang, Lingyan Zhu
更新时间: 2021-08-09
摘要: Heavy metals accumulate in active sludge, and their fate and environmental risks might change during disintegration, which is essential for the subsequent treatment of the active sludge. In this study, the distribution of heavy metals (Zn, Cr, Cd, Ni, and Pb), transformation of their speciation fractions and leaching potentials were explored. Meanwhile, to explore the reasons for the changes, the evolution in morphology of sludge flocs and extracellular polymer substances (EPS) were also examined. The results showed that accompanied by the destruction of sludge flocs and the release of inner organic materials, large numbers of wrapped heavy metals were released from the solid phase into the liquid phase under discharge plasma treatment, especially for those organic bounded metals. As a consequence, the ratio of oxidizable fractions (F3) gradually decreased. The contamination degree and environmental risks of heavy metals were evaluated based on the fraction contents, and it was concluded that discharge plasma treatment could be in favor of reducing the contamination degree and environmental risks. In addition, the leaching contents of Cr decreased after plasma oxidation, while Pb, Zn, Ni and Cd contents increased; but were far below the limit values.

17612. 题目: Exploring changes in bacterioplankton community structure in response to tannic acid, a major component of mangrove litterfall of Sundarbans mangrove ecosystem: a laboratory mesocosm approach
文章编号: N21080813
期刊: Environmental Science and Pollution Research
作者: Anwesha Ghosh, Punyasloke Bhadury
更新时间: 2021-08-08
摘要: Tannic acid is a secondary compound produced by vascular plants and is a major component of mangrove litterfall. Tannic acid is water soluble, leaches out from mangrove litterfall and contributes to DOC and DON pools in adjacent estuaries. About 50% of the litterfall may be degraded and channelized into the marine microbial loop. The influence of tannic acid on bacterioplankton community structure was tested by setting up laboratory-based barrel experiments. Estuarine water from Stn3 of Sundarbans Biological Observatory Time Series (SBOTS) was enriched with tannic acid, and the change in concentration of dissolved nutrients was determined on a daily basis over a span of 15 days. Concentrations of tannic acid, gallic acid and other dissolved nutrients such as nitrate and ortho-phosphate were determined using a UV-Vis spectrophotometer. Tannic acid significantly affected the concentrations of gallic acid and dissolved nitrate in the barrels. Degradation of tannic acid was tracked by a decrease in concentration of tannic acid and generation of gallic acid. The influence of tannic acid on bacterioplankton community structure was analysed on the start (day 0), intermediate (day 3, day 5, day 7 and day 9) and end (day 15) of the experiment. Bacterioplankton community structure was elucidated by sequencing the V3-V4 region of 16S ribosomal RNA on an Illumina MiSeq platform. Proteobacteria was found to be the most dominant bacterial phylum in control and tannic acid-enriched barrels (barrels 1 and 2) on day 0. With the progression of experiment, the abundance of Proteobacteria altered significantly in the control barrel indicating the possible role of this phylum in the breakdown of tannic acid within estuarine mangroves. The abundance of Proteobacteria in the tannic acid-enriched barrels remained high, indicating that members of Proteobacteria may be capable of using tannic acid as a source of carbon and nitrogen. Tannic acid appeared to inhibit most of the other bacterioplankton phyla including Actinobacteria, Acidobacteria and Verrucomicrobia that existed in large abundance in the control barrel on day 15 but were almost absent in the tannic acid-enriched barrels. At class level, Bacteroides was found to be present in highest abundance in the tannic acid-enriched barrels. Tannic acid appeared to strongly influence the abundant bacterioplankton phyla and families as indicated by Pearson's correlation coefficient and non-metric multidimensional scaling ordination plots. Gallic acid is one of the final products of tannic acid degradation. Breakdown of tannic acid could influence the marine nitrogen and carbon cycling by releasing DON and DOC, respectively, into the adjacent estuaries. Information of breakdown and remineralization of components of litterfall such as tannic acid would also be important for calculation of carbon and nitrogen budgets of coastal ecosystems including in mangroves.

17613. 题目: Extracellular polymeric substances in green alga facilitate microplastic deposition
文章编号: N21080812
期刊: Chemosphere
作者: Kishore Gopalakrishnan, Donna R. Kashian
更新时间: 2021-08-08
摘要: Microplastics (MPs) are globally ubiquitous in sediments and surface waters. Interactions between biota and MPs are complex and influence their fate and effects in the environment. Once MPs enter aquatic systems, they are colonized by biofilms that may form from the excretion of extracellular polymeric substances (EPS) from microalgae. Biofilm accumulation may change the density of the MPs, contributing to their transport to the sediments. Furthermore, benthic plantivores may consume biofilm laden MPs allowing them to enter the food web. Thus, it is crucial to understand the role algae plays in the vertical transport of MPs in the aquatic environment. In this study, Chlamydomonas was cultured with MPs at different concentrations (0–0.4 mg/mL), and temperatures ranging from 2.5 to 32.5 °C to understand the deposition dynamics and impacts of MPs on EPS production and algal density. Temperatures ranging up to 25 °C increased algal density and MPs deposition. However, at 32.5 °C, algal density and MPs deposition declined. The quantity of MPs also affected algal cell density and EPS production. MPs concentration from 0 to 0.4 mg/mL increased EPS production at all temperatures. Similarly, an increase in algal cell density and MPs deposition occurred when MPs concentration was raised to 0.3 mg/mL. Algal cultures exposed to 0.3–0.4 mg/mL of MPs had a decrease in algal cell density, with no corresponding decline in EPS production. At certain conditions, MPs can facilitate biofilm formation by stimulating EPS production, which can increase cell density thereby expediting MPs transport to the sediment.

17614. 题目: Dynamics of low-molecular-weight organic acids for the extraction and sequestration of arsenic species and heavy metals using mangrove sediments
文章编号: N21080811
期刊: Chemosphere
作者: Kang Mei, Guirong Wu, Jingchun Liu, , Hualong Hong, Haoliang Lu, Chongling Yan
更新时间: 2021-08-08
摘要: Mangrove wetlands are subjected to pollution due to anthropogenic activities. Mangrove fitness is mainly determined by root exudates and microorganisms activities belowground, but the mechanisms are not yet well known. Rhizospheric interactions among mangrove sediments, microorganisms and root exudates were simulated. In particular, low-molecular-weight organic acids (LMWOA), were examined to explore the metal(loid)s rhizospheric dynamics via batch experiments. Using a combination of comparative sterilised and unsterilised sediments, LMWOA extracts and sediments constituents were examined. Factors such as the solution pH, dissolved organic carbon (DOC), arsenic and iron species and metal(loid)s in the aqueous phase were evaluated. The results show that on an average, the As decreased by 68.3 % and 42.1 % under citric and malic acid treatments, respectively, after sterilisation. In contrast, the As content increased by 29.6 % under oxalic acid treatment. Microorganisms probably facilitate sediment As release in the presence of citric and malic acids but suppress As mobilisation in the presence of oxalic acid. Fe, Mn and Al were significantly (p < 0.05) positively correlated with the trace metal(loid)s (Zn, Pb, Ni, Cu, Cr, Co, Ba, Cd and As). The solution pH was negatively correlated with the solution As. Both DOC and pH reach the peaks at the end of all treatments. The As absorption–desorption dynamics are closely linked to proton consumption, Fe-Mn-Al sedimentation of ageing performance and organic ligand complexation. The study provides an insight into the rhizospheric processes of microbial involvement and gives an enlightening understanding of the metal(loid)s redeployment for plant adaptation in mangrove wetlands.

17615. 题目: Molecular insight into the variation of dissolved organic phosphorus in a wastewater treatment plant
文章编号: N21080810
期刊: Water Research
作者: Shu-Xian Gao, Xin Zhang, Wen-Yuan Fan, Guo-Ping Sheng
更新时间: 2021-08-08
摘要: To date, eutrophication becomes a great concern of vulnerable aquatic systems. Dissolved organic phosphorus (DOP) discharged from wastewater treatment plant (WWTP) holds a large source of phosphorus in receiving water. However, due to the complexity of DOP, their variation and fate in WWTP remain unknown at the molecular level, and are always overlooked. Here, the variation of DOP in a WWTP was uncovered via Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Results show that 95% of DOP in the influent could be removed by the secondary biological treatment processes. The removed DOP species were mainly lipids with the molecular characteristics of low oxygen content, low unsaturation and low aromaticity. Meanwhile, during biological treatments, some new DOP species, especially lignin/carboxylic rich alicyclic molecules (CRAM) that possessed high oxygen content, high unsaturation and high aromaticity, were produced and released into the secondary effluent. In the subsequent tertiary treatment, coagulation by aluminum salt tended to remove high molecular weight and high oxygen content DOP species in the secondary effluent, which was complementary to the biological treatment. However, the sand filter usually retained microorganisms, which would result in the generation of new DOP species in this process. During the final ultraviolet disinfection process, DOP was effectively mineralized to phosphate, especially the species with high molecular weight and highly unsaturated aromatic DOP species (e.g., lignin/CRAM and tannin), which had higher UV absorbance. The revealed variation of DOP in WWTP is beneficial to optimize the treatment processes to enhance the removal of DOP.

17616. 题目: Enhancement of Cr(VI) decontamination by irradiated sludge biochar in neutral conditions: Evidence of a possible role of persistent free radicals
文章编号: N21080809
期刊: Separation and Purification Technology
作者: Zheng Tang, Yifan Kong, Song Zhao, Hanzhong Jia, Davide Vione, Yanming Kang, Pin Gao
更新时间: 2021-08-08
摘要: The effect of photo-irradiation on the removal of Cr(VI) by sludge biochar in neutral conditions is here investigated. The results indicate that photo-irradiation can significantly enhance the removal of aqueous Cr(VI) by sludge biochar. The apparent removal rate constants under ultraviolet (0.61 h−1) and visible-light (0.27 h−1) irradiation are more than 5 and 2 times higher, respectively, than that in the dark (0.11 h−1). Cr(VI) reduction plays a predominant role in Cr removal, accounting respectively for 71.8% (dark), 71.9% (visible light irradiation), and 92.3% (ultraviolet irradiation) of total removal. The abundance of persistent free radicals (PFRs) in biochar (produced hydrothermally at a temperature of 220°C, a reaction time of 2 h, and a solid weight ratio of 40%w) can reach up to 4.72×1016 spins/g, and their EPR signal intensity remains almost unchanged within 720 min in the dark. Ultraviolet irradiation may promote PFRs production in biochar, and PFRs (especially the oxygen-centered ones) act as electron donors to transform Cr(VI) into Cr(III), thereby contributing to Cr(VI) reduction. Our findings shed new light on the role of irradiation in enhancing the removal of Cr(VI) by sludge biochar under neutral conditions, which can be an interesting technique in the field of environmental remediation.

17617. 题目: Quantitative visual analysis of marine barite microcrystals: Insights into precipitation and dissolution dynamics
文章编号: N21080808
期刊: Limnology and Oceanography
作者: Tricia Light, Richard Norris
更新时间: 2021-08-08
摘要: The accumulation rate of authigenic barite (BaSO4) in marine sediments is a promising proxy for reconstructing marine export production, but many aspects of barite precipitation and dissolution in the water column remain unknown. Here, we collected, imaged, and quantitatively analyzed 5481 barite microcrystals in bottle casts from the Eastern Pacific water column to gain a better understanding of in situ barite dynamics. Barite crystal abundance increases rapidly between the surface and 500 m in depth and then declines to predominantly low abundances below ~ 1000 m. The falloff in barite abundance between the oxygen minimum zone (OMZ) and the ocean interior suggests 60% ± 20% loss of barite by dissolution, nearly all of which is complete by water depths of 1000 m. However, there are occasional samples, as deep as 1250 m, with unusually high barite abundance that may represent marine snow deposition events. We found that microcrystals associated with organic matter substrates were smaller and less solid than free crystals, which suggests ongoing barite precipitation toward larger, more regularly shaped microcrystals within organic matter aggregates. Trends in barite microcrystal size with depth suggest that organic matter aggregates also play a role in shielding barite microcrystals from dissolution. In addition, our extensive data set raises new questions regarding marine barite nucleation and spatial heterogeneity. By helping bridge the gap between hypothesized barite dynamics and in situ observations of barite microcrystals, this study advances our understanding of water column Ba processes and the utility of sediment barite as an export production proxy.

17618. 题目: Budget of riverine nitrogen over the East China Sea shelf
文章编号: N21080807
期刊: Environmental Pollution
作者: Jing Zhang, Xinyu Guo, Liang Zhao
更新时间: 2021-08-08
摘要: Riverine nitrogen loading to the continental shelf sea is important for terrestrial–marine linkage and global nitrogen cycling and leads to serious marine environmental problems. The budget and cycle of riverine nitrogen over the continental shelf in the East China Sea (ECS) are unknown. Using the tracking technique within a physical–biological coupled model, we quantified the nitrogen budgets of riverine dissolved inorganic nitrogen (DIN) and particulate organic nitrogen (PON) over seasonal to annual scales in the ECS, especially from the Changjiang River, which plays a dominant role in riverine nitrogen input. The horizontal distributions of the Changjiang DIN and PON generally followed the Changjiang diluted water and coastal currents and were affected by stratification in the vertical direction. Their inventory variations were dominated by biological fluxes and modulated by physical ones, and changed most dramatically in the inner shelf among three subregions. Less than half of DIN were converted to PON with most of the rest leaving the ECS through lateral transport pathways, among which the flux through the Tsushima Strait was dominant. With the increasing loading of the Changjiang DIN flux from the 1980s–2010s, lateral transports rather than PON production increased due to limited primary production. Approximately 60 % of the produced PON exported to the sediment and 34 % went to the Tsushima Strait. According to the export production, the DIN from the Changjiang River contributed 12–42 % to the ECS carbon sequestration.

17619. 题目: Integrating ecosystem metabolism and consumer allochthony reveals nonlinear drivers in lake organic matter processing
文章编号: N21080806
期刊: Limnology and Oceanography
作者: Meredith A. Holgerson, Rachel A. Hovel, Patrick T. Kelly, Lauren E. Bortolotti, Jennifer A. Brentrup, Amber R. Bellamy, Samantha K. Oliver, Alexander J. Reisinger
更新时间: 2021-08-08
摘要: Lakes process both terrestrial and aquatic organic matter, and the relative contribution from each source is often measured via ecosystem metabolism and terrestrial resource use in the food web (i.e., consumer allochthony). Yet, ecosystem metabolism and consumer allochthony are rarely considered together, despite possible interactions and potential for them to respond to the same lake characteristics. In this study, we compiled global datasets of lake gross primary production (GPP), ecosystem respiration (ER), and zooplankton allochthony to compare the strength and shape of relationships with physicochemical characteristics across a broad set of lakes. GPP was positively related to total phosphorus (TP) in lakes with intermediate TP concentrations (11–75 μg L−1) and was highest in lakes with intermediate dissolved organic carbon (DOC) concentrations. While ER and GPP were strongly positively correlated, decoupling occurred at high DOC concentrations. Lastly, allochthony had a unimodal relationship with TP and related variably to DOC. By integrating metabolism and allochthony, we identified similar change points in GPP and zooplankton allochthony at intermediate DOC (4.5–10 mg L−1) and TP (8–20 μg L−1) concentrations, indicating that allochthony and GPP may be coupled and inversely related. The ratio of DOC:nutrients also helped to identify conditions where lake organic matter processing responded more to autochthonous or allochthonous organic matter sources. As lakes globally face eutrophication and browning, predicting how lake organic matter processing will respond requires an updated paradigm that incorporates nonlinear dynamics and interactions.

17620. 题目: Comparative efficacy of raw and HNO3-modified biochar derived from rice straw on vanadium transformation and its uptake by rice (Oryza sativa L.): Insights from photosynthesis, antioxidative response, and gene-expression profile
文章编号: N21080805
期刊: Environmental Pollution
作者: Sajid Mehmood, Waqas Ahmed, Muhammad Rizwan, Muhammad Imtiaz, Ahmed Said Mohamed Ali Elnahal, Allah Ditta, Sana Irshad, Muhammad Ikram, Weidong Li
更新时间: 2021-08-08
摘要: Low concentrations of vanadium (V) are essential for various plant species but it becomes toxic to plants, animals, and humans at high levels. A significant amount of V is currently being emitted into the atmosphere due to intensified industrial processing. Therefore, this study aimed at evaluating the effect of raw (BC) and HNO3-modified biochar (OBC) derived from rice straw on growth, photosynthetic assimilation, relative chlorophyll content, SPAD index, ion leakage, enzyme activities, hydrogen peroxide (H2O2), bioavailability and V uptake by rice in a laboratory-scale experiment. Characterization of OBC and BC by FTIR (Fourier transform infrared spectroscopy), SEM (scan electron microscopy), BET (Brunauer–Emmett–Teller), elemental analysis, and z-potential revealed a substantial difference between both of them. The V-stress significantly reduced the rice plant growth, biomass yield, chlorophyll parameters, root length and surface area. Under V-stress conditions, root accumulated more V than shoots and OBC significantly improved the above-mentioned parameters, while, decreasing hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels in plants. The antioxidant function and gene expression levels induced by V-stress and OBC application further increased the expression profile of three genes (SOD, POD, and CAT) encoding antioxidant enzymes and one metal-tolerant conferring gene (OsFSD1). In summary, these results demonstrated the critical role of OBC in mitigating the detrimental effects of high V-stress on rice growth and enhancing plant defence against V-stress.