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17601. 题目: Optimizing organic amendment applications to enhance carbon sequestration and economic benefits in an infertile sandy soil
文章编号: N21112612
期刊: Journal of Environmental Management
作者: Cong Xu, Jidong Wang, Di Wu, Chuanzhe Li, Lei Wang, Cheng Ji, Yongchun Zhang, Yuchun Ai
更新时间: 2021-11-26
摘要: A thorough understanding of the agricultural, ecological, and economic benefits of organic amendment (OA) application in infertile soils is crucial for facilitating agricultural sustainability. We conducted a three-year field study to evaluate the effects of OA application on soil organic carbon (SOC) sequestration, crop yields, and the net ecosystem economic benefit (NEEB) in a typical infertile sandy soil (with an initial SOC content of 2.56 g kg−1) of the ancient Yellow River alluvial plain. In addition to the control (CK; non-OA application), two types of OAs, namely, manure-based organic fertilizer (M) and spent mushroom residue (MR), were each applied at 12, 24, and 36 Mg ha−1 yr−1. Two scenarios of OA application practices, namely, conventional manual OA application (AMA) and mechanical OA application (AME), were considered in the economic evaluation. An increase of 1 g kg−1 SOC content could improve the crop yield by 2.25 Mg ha−1 yr−1. Compared with the CK, the application of OAs enhanced the SOC content and SOC stock by 14.6%–39.8% and 8.5%–28.2%, respectively. However, the SOC sequestration efficiency of the OAs tended to decrease under high rates of OA application. MR was observed to have greater potential than M in sequestering SOC and promoting soil aggregates. OA-induced SOC sequestration could neutralize 36.6%–97.8% of greenhouse gas emissions, which resulted in a reduction in the global warming potential and its cost by 0.62–2.68 Mg CO2-eq ha−1 yr−1 and 15.46–65.78 CNY ha−1 yr−1, respectively. Nevertheless, in terms of the NEEB, the benefits of OA application on crop yield and SOC sequestration were largely offset by the increased material and labor costs. Compared with AMA, AME could save 10%–27% of agricultural costs. The AME of MR at a rate of 24 Mg ha−1 yr−1 achieved the highest NEEB. The results of this study suggest that a strategy involving the appropriate OA, optimal application rate, and cheapest incorporation cost for a specific individual soil should be adopted to achieve a sustainable solution for promoting crop productivity, enhancing SOC sequestration, and ensuring farmer income in infertile farming regions.

17602. 题目: Mechanisms and application of the IAST-EBC model for predicting 2-MIB adsorption by PAC in authentic raw waters: Correlation between NOM competitiveness and water quality parameters
文章编号: N21112611
期刊: Journal of Hazardous Materials
作者: Junying Ren, Sihui Yang, Lei Li, Shuili Yu, Naiyun Gao
更新时间: 2021-11-26
摘要: Natural organic matter (NOM) exerts negative impacts on 2-methylisoborneol (2-MIB) removal by powdered activated carbon (PAC), thus adding to the difficulty in accurate PAC dose prediction. Our study investigated the application of the ideal adsorbed solution theory-equivalent background compound (IAST-EBC) model and its simplified version for PAC dose prediction. Four raw water samples were employed, and the corresponding C0,EBC values, indicating NOM competitiveness, were calculated. The results showed that the IAST-EBC model presented ideal predictive performance in 2-MIB adsorption under both equilibrium and nonequilibrium conditions and the C0,EBC values of the Huangpu River (8800ng/L) and Qiantang River (10300ng/L) were high, representing the higher NOM competitiveness in these two rivers, which may be caused by municipal effluent and industrial wastewater discharge. In contrast, Tai Lake water showed a lower C0,EBC value (6400ng/L), which was likely associated with algae and other microbial activities. The fluorescence index (FI, the ratio of Ex/Em = 370/470nm to Ex/Em = 370/520nm) can be applied to estimate C0,EBC, thus facilitating prediction. Our study also showed that the IAST-EBC model can be further simplified under lower initial 2-MIB concentrations or longer contact times, which is particularly useful for practical applications.

17603. 题目: Influence of lead on the activity of soil microorganisms in two Beskidy landscape parks
文章编号: N21112610
期刊: Environmental Monitoring and Assessment
作者: Jacek Borgulat, Włodzimierz Łukasik, Anna Borgulat, Aleksandra Nadgórska-Socha, Marta Kandziora-Ciupa
更新时间: 2021-11-26
摘要: The aim of the study was to assess the potential impact of lead on soil metabolism in two landscape parks localized in the Beskid Śląski and Beskid Żywiecki mountains which were affected, among others, by air pollution from the Upper Silesian Industrial Region, the largest industrial zone in Poland. The study was carried out in six locations with different lead levels in the soil environment. Each plot was equipped with four pairs of vacuum ceramic lysimeters to assess the mobility of Pb in the soil. The metabolic activity was assessed by measuring: soil enzyme activity, soil respiration and by studying community-level physiological profiling (CLPP) using Biolog EcoPlates technique. The soil to the examination was collected near the stands with the lysimeters from two soil horizons (A and B layer). The analyses carried out showed that the factors that had the greatest influence on lead mobility were the organic carbon content and the soil pH. The elevated lead level in the topsoil (layer A) could affect the functional biodiversity of soil microorganisms, but low soil pH was a more likely limiting factor. In the subsoil (layer B), lower lead content was found and its probable effect on soil microbial activity was small. In summary, it can be concluded that the assessment of the influence of heavy metals on soil metabolism is not easy, and the Biolog system has proven to be a sensitive tool for assessing the potential impact of heavy metals on the soil environment.

17604. 题目: HUMIC LIKE SUBSTANCES EXTRACTED FROM OIL MILL WASTES IN PHOTO-FENTON PROCESSES: CHARACTERIZATION, PERFORMANCE AND TOXICITY ASSESMENT
文章编号: N21112609
期刊: Journal of Environmental Chemical Engineering
作者: P. García-Negueroles, S. García-Ballesteros, L. Santos-Juanes, C. Sabater, M.A. Castillo, M.F. López-Pérez, R. Vicente, A.M. Amat, A. Arques
更新时间: 2021-11-26
摘要: Olive mill waste has been used as sourcing materials for the isolation of humic like substances (OMW-HLS) which have demonstrated its capacity to expand the range of applicability of photo-Fenton process to pH=5. During the isolation process, membranes of three different pore sizes (300kDa, 150kDa and 50kDa) were employed in order to obtain three batches of OMW-HLS. Four pollutants contained in 2013/39/EC were used as target substances: terbutryn (TBT), diclofenac (DCF), chlorfenvinphos (CVF) and pentachlorophenol (PCP). Results showed that OMW-HLS was able to enhance photo-Fenton at pH = 5, but differences were not significant, either among fractions or with commercial humic substances. Reactions were scaled-up and driven under real sunlight and pollutants removal was faster in the presence of OMW-HLS. Toxicity was monitored according to bioassays based on different organisms or cell lines. Detoxification was observed with and without OMW-HLS, although higher toxicity was detected in the presence of humic acids, most probably due to the surfactant effect, that allows a better contact between pollutant and organism.

17605. 题目: Paleo-vegetation and environmental history of Natural Trap Cave based on pollen and carbon isotope analyses
文章编号: N21112608
期刊: Quaternary International
作者: Thomas A. Minckley, Mark T. Clementz, David Lovelace
更新时间: 2021-11-26
摘要: Pollen and carbon isotope data from Natural Trap Cave provides insights into the environmental conditions of the Bighorn Basin, in north-central Wyoming, USA during the time intervals 151.1 to 132.2 cal ka BP, 51.8 to 17.4 cal ka BP, and 10.4 cal ka BP to present. Similarities between the buildup of the penultimate and last glacial maxima include abundant Artemisia, Amaranthaceae, Asteraceae, and Poaceae pollen, which, when combined with high δ13C values (>−25.0‰) and low plant discrimination values (18.0–19.0‰) from sedimentary organic matter, indicate steppe-like, cold-dry conditions. Between 151 and 142.5 cal ka BP, abundant Poaceae associated with much lower δ13C values (−28.0‰ to −26.0‰) and higher plant discrimination values (19.0‰–21.0‰) could be indicative of relatively wet summers. Similarly, after 25 cal ka BP increases in Poaceae may indicate wet conditions during the growing season. Holocene conditions differ from the earlier sections of the record, with greater arboreal pollen abundance (i.e., Pinus), consistent with woodland expansion in the region. Carbon isotope data from sedimentary organic matter show the Holocene was more humid than the glacial conditions of the late Pleistocene. This is especially clear at the start of the Holocene when a large negative carbon isotope excursion (CIE, < −28.0‰) occurred, providing a distinct chemostratigraphic marker defining the Pleistocene-Holocene boundary within these cave sediments. The association of this CIE with a pronounced spike in Pinus pollen supports an interpretation of a short-lived interval (<1000 years) of extremely warm, wet, forested conditions at this site.

17606. 题目: Molecular diversity of liquid digestate from anaerobic digestion plants for biogenic waste
文章编号: N21112607
期刊: Bioresource Technology
作者: Pinjing He, Yulong Huang, Junjie Qiu, Hua Zhang, Liming Shao, Fan Lü
更新时间: 2021-11-26
摘要: The treatment and valorization of liquid digestate (ADLD) after anaerobic digestion of biogenic waste are challenging. This study used ultra-high resolution mass spectrometry to determine the molecular characteristics of ADLD collected from different full-scale plants for food waste treatment. The results indicated that there were regular differences in the dissolved organic matter (DOM) indicators among the samples from dry and wet anaerobic processes. ADLD DOM had higher H/C and O/C, and contained more easily degradable proteins. In addition, sCOD and pH were the drivers of the molecular distribution of ADLD common compounds. The same common compounds were present in the ADLD from different anaerobic digestion plants. They had a significant correlation with physicochemical characteristics. The compounds relating to plant hormones and nutrients as well as xenobiotics were both identified, suggesting that comprehensive considerations should be taken into account for the land application of ADLD.

17607. 题目: A novel biotechnology based on periphytic biofilms with N-acyl-homoserine-lactones stimulation and lanthanum loading for phosphorus recovery
文章编号: N21112606
期刊: Bioresource Technology
作者: Ying Xu, Philip G. Kerr, Jan Dolfing, Bruce E. Rittmann, Yonghong Wu
更新时间: 2021-11-26
摘要: This study presents an approach for developing periphytic biofilm with N-acyl-homoserine-lactones (AHLs) stimulation and lanthanum (La, a rare earth element) loading, to achieve highly efficient and stable phosphorus (P) recovery from wastewater. AHLs stimulated biofilm growth and formation, also improved stable P entrapment by enhancing extracellular polymeric substance (EPS) production and optimizing P-entrapment bacterial communities. Periphytic biofilms loading La is based on ligand exchanges, and La loading achieved initial rapid P entrapment by surface adsorption. The combination of AHLs stimulation and La loading achieved 99.0% P entrapment. Interestingly, the enhanced EPS production stimulated by AHLs protected biofilms against La. Moreover, a method for P and La separately recovery from biofilms was developed, achieving 89-96% of P and 88-93% of La recovery. This study offers a promising biotechnology to reuse La from La-rich wastewater and recover P by biofilm doped with La, which results in a win-win situation for resource sustainability.

17608. 题目: Removal of heavy metals from wastewaters with biochar pyrolyzed from MgAl-layered double hydroxide-coated rice husk: Mechanism and application
文章编号: N21112605
期刊: Bioresource Technology
作者: Anyu Li, Yue Zhang, Wenzhan Ge, Yutong Zhang, Lihu Liu, Guohong Qiu
更新时间: 2021-11-26
摘要: This study reports a MgAl–LDH rice husk biochar composite (MgAl–LDH@RHB) with a regular hydrotalcite structure synthesized by a simple hydrothermal method, which was then used to remove Cd(II) and Cu(II) from water. The influencing factors on the adsorption performance were determined through batch adsorption experiments, and the adsorption characteristics and cycling capacity were evaluated with eight models and adsorption-desorption experiments. The results showed that the adsorption of Cd(II) and Cu(II) by MgAl–LDH@RHB conformed to the Langmuir-Freundlich model and PSO kinetics model, indicating single-layer chemical adsorption. In addition, the experimental maximum adsorption capacities for Cd(II) and Cu(II) were 125.34 and 104.34 mg g–1, respectively. The adsorption of Cd(II) and Cu(II) by MgAl–LDH@RHB was dominated by surface precipitation and ion exchange. The findings reveal the mechanism for the heavy metal removal by MgAl–LDH@RHB and provide a theoretical reference for agricultural waste disposal and water pollution control.

17609. 题目: Enhanced biogas production in anaerobic digestion of sludge medicated by biochar prepared from excess sludge: Role of persistent free radicals and electron mediators
文章编号: N21112604
期刊: Bioresource Technology
作者: Xiang Liu, Qingting Meng, Fengjie Wu, Chen Zhang, Xuejun Tan, Chunli Wan
更新时间: 2021-11-26
摘要: The addition of biochars to promote the efficiency of anaerobic digestion (AD) has widely received concerns. However, the role of persistent free radicals (PFRs) and the electron transfer ability of biochar in AD has not yet been noticed. In this study, biochars were prepared from excess sludge under 400°C (B400) or 600°C (B600) and different ratios of sludge to biochar (5:1, 10:1, 20:1) were applied in the AD of sludge. The results verified that PFRs in biochar participated in the sterilization of microorganisms in sludge, resulting in the release of organic matters. Similar to electron mediators, biochars possessed electron exchangeability and the addition of biochars boosted the biogas production by maximum of 54.5%. The enhancing effect of B400 surpassed that of B600 as high temperature destroyed functional groups and reduced the defect degree of biochar. This study achieved in-situ resource utilization and provided references for the improvement of anaerobic digestion.

17610. 题目: Stabilization of lead and cadmium in soil by sulfur-iron functionalized biochar: Performance, mechanisms and microbial community evolution
文章编号: N21112602
期刊: Journal of Hazardous Materials
作者: Jianhua Qu, Yihang Yuan, Xinmiao Zhang, Lei Wang, Yue Tao, Zhao Jiang, Hui Yu, Min Dong, Ying Zhang
更新时间: 2021-11-26
摘要: Sulfur-iron functionalized biochar (BC-Fe-S) was designed by simultaneously supporting Fe2O3 nanoparticles and grafting sulfur-containing functional groups onto biochar to stabilize Pb and Cd in soil. The BC-Fe-S exhibited excellent stabilization performance for Pb and Cd with fast kinetic equilibrium within 5 days associating with pseudo-second-order model. The bioavailable-Pb and -Cd contents decreased by 59.22% and 70.28% with 3% BC-Fe-S treatment after 20 days of remediation. Speciation transformation analysis revealed that the increase of stabilization time and BC-Fe-S dosage with appropriate soil moisture and pH promoted toxicities decrease of Pb and Cd with transformation of labile fractions to more steady fractions. The labile fractions of Pb and Cd decreased by 12.22% and 16.21% with 3% BC-Fe-S treatment, and transformed to the residual speciation. Meanwhile, wetting-drying and freezing-thawing aging did not markedly alter the bioavailability of Pb and Cd, proving that the BC-Fe-S holds promise for stabilization of Pb and Cd in varying environmental conditions. 16S rRNA sequencing analysis demonstrated that the BC-Fe-S significantly improved diversity and composition of microbial community, especially increasing the relative abundance of heavy metal-resistant bacteria. Overall, these results suggested BC-Fe-S as a high-performance and environmental-friendly amendment with stability to remediate heavy metals polluted soil.

17611. 题目: Hourly emission estimation of black carbon and brown carbon absorption from domestic coal burning in China
文章编号: N21112601
期刊: Science of The Total Environment
作者: Qin Yan, Shaofei Kong, Yingying Yan, Xi Liu, Shurui Zheng, Si Qin, Fangqi Wu, Zhenzhen Niu, Huang Zheng, Yi Cheng, Xin Zeng, Jian Wu, Liquan Yao, Dantong Liu, Shihua Qi
更新时间: 2021-11-26
摘要: Residential coal combustion (RCC) emission demonstrates obvious daily variation, while no real-time estimation of air pollutants from RCC has been reported, as the limitation of hourly activity data and emission factors. With a dilution sampling system, a high-precision electronic balance, and an Aethalometer Model AE33, a real-time monitoring platform for RCC emission was established. Hourly emission factors (EFs) of BC and absorption emission factors (AEFs) of BrC from eleven kinds of chunk coals and nine kinds of honeycomb coals burning in China were obtained. The monthly and hourly coal consumption amounts were calculated with the activity data from literature reviews and a field survey. The first hourly BC and absorption cross section of BrC emission inventories from RCC were established in China. The historical emission trends (2003–2017) indicated that the policy has rapidly controlled the emission of BC and ACSBrC from RCC in urban area (26.7% and 31.8% decreased, respectively in 2013). While in rural areas, their emission continually increased by 1.2% ~ 5.3% until more strict law enacted in 2017. Emissions of BC and ACSBrC in winter seasons were 60.1 Gg and 1064.1 Gm2, which accounted for 54.3% and 55.1% of the total BC and ACSBrC emissions correspondingly. The peak values of hourly emission of BC and ACSBrC (in 370 nm) normally appeared at 19:00–23:00, accounting for 43.0% and 41.5% of their total daily emission. The low emission periods were at cooking times including 7:00, 12:00, and 17:00 of a day and the whole emission of BC and ACSBrC for the three periods accounted for 1.8% and 2.3% of their daily emission. This high-resolution BC and ACSBrC emission inventories can be useful for future modeling works on the formation and evolution of a haze event, the smoke aging and transportation, as well as corresponding climate and human health effects.

17612. 题目: Accumulation and distribution of zinc in rice plants (Oryza sativa L.) growing in zinc contaminated paddy soils with biochar
文章编号: N21112511
期刊: Journal of Environmental Chemical Engineering
作者: Honghong Li, Zhou Li, Shengcong Xie, Yongxin Huang, Miaofen Chen, Tuanhui Xie, Guo Wang
更新时间: 2021-11-25
摘要: At low concentrations zinc (Zn) is essential for plants and animals, but it becomes toxic when it exceeds a critical level. This study aimed to explore the effects of biochar on the remediation of Zn-polluted soil and the distribution of Zn in rice plants using pot experiments. Various amounts of biochar (0% (control), 2.5%, and 5% w/w) derived from rice straw were mixed with Zn-contaminated soil collected from farmland near a mine. The results showed that biochar enhanced the biomass of rice tissues and significantly reduced the concentration of Zn in brown rice. These results could be attributed to the combination of several effects: (1) Biochar increased the soil pH and organic carbon content, resulting in a reduction in the concentration of soil available Zn and transforming forms of immobilized Zn from acid soluble to reducible. (2) Biochar addition decreased the amorphous iron and complex iron concentrations in the soil solution and reduced the formation of root Fe plaques as well as the storage of Zn in iron plaques, thus diminishing the probability of Zn transfer from root surfaces to tissues. (3) Biochar played a key role in abating the toxic effect of Zn in rice plants as it decreased the transfer of Zn from roots to leaves and promoted Zn storage in the vacuoles of root cells. These results suggest that the application of biochar to Zn-contaminated soil is effective in reducing Zn accumulation in rice grains and can enhance rice production.

17613. 题目: Efficacy of rice husk biochar and compost amendments on the translocation, bioavailability, and heavy metals speciation in contaminated soil: Role of free radical production in maize (Zea mays L.)
文章编号: N21112510
期刊: Journal of Cleaner Production
作者: Muhammad Saqib Rashid, Guijian Liu, Balal Yousaf, Yu Song, Rafay Ahmed, Abdul Rehman, Muhammad Arif, Samina Irshad, Ayesha Imtiyaz Cheema
更新时间: 2021-11-25
摘要: The present study investigated the effectiveness of rice husk biochar (RHB) and chicken manure compost (CMC) amendments on the potential mobility of heavy metals (HMs) and the growth of maize plants in contaminated soil. Results indicated that the potential mobile fraction of Cr (44.43%), Ni (29.93%), and Zn (44.68%) accounted for T2 (2% RHB), whereas Cu (69.33%) and Pb (34.38%) for T4 (1% RHB + 1% CMC) of their total amount. Amending the soil resulted in a significant increase in maize growth and biomass production, whereas T4 showed an increment of 156% in fresh maize weight. While root biomass was highest with T2 treatment, which increased fresh and dry weight by 35% and 90%. The bioaccumulation factor (BF) and Translocation factor (TF) were less than one indicating that the low content of HMs accumulation in roots from soil and slight transferred to shoot (edible tissues). The results of electron paramagnetic resonance (EPR) revealed the generation of hydroxyl radical (•OH) as reactive oxygen species (ROS) in root and shoot of maize seedling. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectrum confirmed the complexation and the adsorption of HMs as prominent mechanisms owing to their complexation with hydroxyl, carbonyl and carboxyl groups. The results indicate that the RHB and CMC, especially their combination can be used effectively for the remediation of HMs by reducing their toxicity and bioavailability in food matrices and soils.

17614. 题目: Differences and mechanism of dynamic changes of Cd activity regulated by polymorphous sulfur in paddy soil
文章编号: N21112508
期刊: Chemosphere
作者: Zhen Wang, Wenjing Liu, Jiang Liu, Xiaowei Liu, Rongle Liu, Yujie Zhao
更新时间: 2021-11-25
摘要: Sulfur (S) can decrease the bioavailability of Cd in paddy soil, and therefore reduce Cd uptake by rice. However, the dynamic influence mechanism of different forms of sulfur on the bioavailability of cadmium in soil has not been systematically studied. In this study, we used Diffusive gradients in thin films (DGT) technology and soil pore water sampling technology to investigate the effects of different types of S application on the bioavailability of Cd. The three forms of S are elemental sulfur (S0), sodium sulfate (SO42−), and mercapto-grafted palygorskite (MP), which have been treated in six ways according to CK, SL, SH, SO42L, SO42H, MP (L and H are the low and high levels of treatments). The results showed that soluble and labile Cd concentration was quickly fixed after flooding but activated after rice transplantation. Both MP and SL treatments increased the content of dissolved organic carbon (DOC) and significantly reduced the accumulation of Cd in roots and grains. The Cd content of roots treated with MP was only 0.50 mg kg−1, which was 77.6% lower than the Cd content in CK (2.22 mg kg−1). S promotes the reduction and dissolution of Fe, and the formation of FeS/FeS2 is also one of the reasons for the low bioavailability of Cd, while the SH treatment has a greater effect on lowering pH, so the effect of fixing Cd is not obvious. In addition, SO42− treatment delays the soil reduction process, so it cannot effectively fix Cd. At the stage of rice maturity, dissolved Cd increased in S treatment, but MP treatment did not have this phenomenon. The possible reason was the consumption of DOC or the oxidation of CdS which caused Cd to enter the soil solution. Taken together, Fe–S play a critical role in controlling the mobilization of Cd in paddy systems.

17615. 题目: Trace metal distribution and ecological risk assessment in the core sediments of a highly urbanized tropical mangrove ecosystem, Southwest coast of India
文章编号: N21112507
期刊: Marine Pollution Bulletin
作者: K.S. Moushmi, Anu Susan Cheriyan, Eldhose Cheriyan, Manu Mohan, N. Chandramohanakumar
更新时间: 2021-11-25
摘要: Distribution and ecological risk assessment of trace metals were carried out in the core sediments of a highly urbanized tropical mangrove ecosystem along the Southwest coast of India. The metal distribution pattern was as follows: Co, Cu, Ni and Pb adsorbed onto Fe oxyhydroxides and fine grained sediments; Cd and Zn preferential adsorption by organic matter and Cr scavenging by Mn oxyhydroxides. Cd, Pb and Zn were significantly enriched in upper sediments, while Cd, Ni and Zn were present in metal exchangeable fractions. Geoaccumulation index (Igeo) suggested that the study area showed moderate to strong pollution of Cd and Zn, whereas unpolluted to moderately polluted with respect to Co, Cr, Cu, Mn, Ni and Pb. Cd enrichment caused high ecological risk, primarily attributed to anthropogenic activities. Mangrove ecosystems are efficient sequester of trace metals but anthropogenic addition can cause significant fraction of exchangeable metals and pose high ecological risk.

17616. 题目: Extractability of global fallout Pu from agricultural soils and its potential indication of bioavailability
文章编号: N21112506
期刊: CATENA
作者: Youyi Ni, Jian Zheng, Qiuju Guo, Zhaoya Huang, Keiko Tagami, Shigeo Uchida
更新时间: 2021-11-25
摘要: We present the first investigation of the extractability of global fallout Pu from agricultural soils under natural conditions and its potential for indication of Pu bioavailability. On average, the nominal water soluble and exchangeable Pu fractions in sampled upland field soils were 0.07 ± 0.07% and 0.02 ± 0.01%, respectively, while those fractions in the rice paddy soils were 0.10 ± 0.06% and 0.03 ± 0.02%, respectively. Sequential extraction results indicated that the dominant sinks of Pu in both upland and paddy soils were the immobile organic matter fraction and the immobile residual fraction. Furthermore, both the water soluble and NH4OAc exchangeable Pu percentages showed a significant negative correlation with the exchangeable Ca2+ concentration in the soils. Regarding the potential plant bioavailability of Pu, we observed a positive correlation (r = 0.549, p = 0.034) between the Pu concentration in rice and the water soluble Pu concentration in the corresponding rice paddy soils, and that illustrated the water soluble Pu fraction was likely to be available for rice plant uptake. This bioavailable fraction was further applied in evaluating the available transfer factor (ATF) of Pu by dividing the Pu concentration in rice with the bioavailable Pu concentration in the corresponding soil. The ATFs of Pu from soil to rice plant ranged from 6.9 × 10−3 to 1.7 × 10−1. Statistical analysis indicated the ATF data were less discrete compared with the conventional transfer factor (TF). Therefore, we consider the ATF to be more representative than the TF to illustrate the transfer ability of Pu from soil to rice plant.

17617. 题目: Climate Effects on Subsoil Carbon Loss Mediated by Soil Chemistry
文章编号: N21112505
期刊: Environmental Science & Technology
作者: Angela R. Possinger, Tyler L. Weiglein, Maggie M. Bowman, Adrian C. Gallo, Jeff A. Hatten, Katherine A. Heckman, Lauren M. Matosziuk, Lucas E. Nave, Michael D. SanClements, Christopher W. Swanston, Brian D. Strahm
更新时间: 2021-11-25
摘要: Subsoils store at least 50% of soil organic carbon (SOC) globally, but climate change may accelerate subsoil SOC (SOCsub) decomposition and amplify SOC-climate feedbacks. The climate sensitivity of SOCsub decomposition varies across systems, but we lack the mechanistic links needed to predict system-specific SOCsub vulnerability as a function of measurable properties at larger scales. Here, we show that soil chemical properties exert significant control over SOCsub decomposition under elevated temperature and moisture in subsoils collected across terrestrial National Ecological Observatory Network sites. Compared to a suite of soil and site-level variables, a divalent base cation-to-reactive metal gradient, linked to dominant mechanisms of SOCsub mineral protection, was the best predictor of the climate sensitivity of SOC decomposition. The response was “U”-shaped, showing higher sensitivity to temperature and moisture when either extractable base cations or reactive metals were highest. However, SOCsub in base cation-dominated subsoils was more sensitive to moisture than temperature, with the opposite relationship demonstrated in reactive metal-dominated subsoils. These observations highlight the importance of system-specific mechanisms of mineral stabilization in the prediction of SOCsub vulnerability to climate drivers. Our observations also form the basis for a spatially explicit, scalable, and mechanistically grounded tool for improved prediction of SOCsub response to climate change.

17618. 题目: Ameliorative effects of biochar on persistency, dissipation, and toxicity of atrazine in three contrasting soils
文章编号: N21112504
期刊: Journal of Environmental Management
作者: Raghavendra Pratap Singh, Mohd Ahsan, Disha Mishra, Versha Pandey, , Anisha Yadav, Puja Khare
更新时间: 2021-11-25
摘要: The presence of atrazine a persistent herbicide in soil poses a serious threat to the ecosystem. The biochar amendment in soil altered the fate of this herbicide by modifying the soil properties. The present study examines the dissipation and toxicity of atrazine in three contrasting soils (silty clay, sandy loam, and sandy clay) without and with biochar amendment (4%). The experiment was performed for 150 days with three application rates of atrazine (4, 8, and 10 mg kg−1). The speciation and degradation of atrazine, metabolite content, microbial biomass, and enzymatic activities were evaluated in all treatments. Three kinetic models and soil enzyme index were calculated to scrutinize the degradation of atrazine and its toxicity on soil biota, respectively. The goodness of fit statistical indices suggested that the first-order double exponential decay (FODE) model best described the degradation of atrazine in silty clay soil. However, a single first order with plateau (SFOP) was best fitted for atrazine degradation in sandy loam and sandy clay soils. The half-life of atrazine was higher in sandy clay soil (27-106 day−1) than silty clay (28-77 day−1) and sandy loam soil (27-83 day−1). The variations in the dissipation kinetics and half-life of the atrazine in three soil were associated with atrazine partitioning, availability of mineral content (silica, aluminum, and iron), and soil microbial biomass carbon. Biochar amendment significantly reduced the plateau in the kinetic curve and also reduced the atrazine toxicity on soil microbiota. Overall, biochar was more effective in sandy clay soil for the restoration of soil microbial activities under atrazine stress due to modulation in the pH and more improved soil quality.

17619. 题目: Polycyclic aromatic hydrocarbon contamination in soils and sediments: Sustainable approaches for extraction and remediation
文章编号: N21112503
期刊: Chemosphere
作者: Thiloka Kariyawasam, Gregory S. Doran, Julia A. Howitt, Paul D. Prenzler
更新时间: 2021-11-25
摘要: Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic environmental pollutants that are extremely hydrophobic in nature and resistant to biological degradation. Extraction of PAHs from environmental matrices is the first and most crucial step in PAH quantification. Extraction followed by quantification is essential to understand the extent of contamination prior to the application of remediation approaches. Due to their non-polar structures, PAHs can be adsorbed tightly to the organic matter in soils and sediments, making them more difficult to be extracted. Extraction of PAHs can be achieved by a variety of methods. Techniques such as supercritical and subcritical fluid extraction, microwave-assisted solvent extraction, plant oil-assisted extraction and some microextraction techniques provide faster PAH extraction using less organic solvents, while providing a more environmentally friendly and safer process with minimum matrix interferences. More recently, more environmentally friendly methods for soil and sediment remediation have been explored. This often involves using natural chemicals, such as biosurfactants, to solubilize PAHs in contaminated soils and sediments to allow subsequent microbial degradation. Vermiremediation and microbial enzyme-mediated remediation are emerging approaches, which require further development. The following summarises the existing literature on traditional PAH extraction and bioremediation methods and contrasts them to newer, more environmentally friendly ways.

17620. 题目: Peroxymonosulfate-assisted photocatalytic degradation of antibiotic norfloxacin by a calcium-based Ag3PO4 composite in water: Reactivity, products and mechanism
文章编号: N21112502
期刊: Journal of Cleaner Production
作者: Zeng-Hui Diao, Shi-Ting Huang, Xie Chen, Meng-Yao Zou, Hui Liu, Peng-Ran Guo, Ling-Jun Kong, Wei Chu
更新时间: 2021-11-25
摘要: Nowadays, environmental problems caused by residual antibiotics are getting increasing attention. In the present work, peroxymonosulfate (PMS) was firstly employed for the enhanced degradation of norfloxacin (NOF) by a calcium-based Ag3PO4 composite (Ca-Ag3PO4) under visible light irradiation. Experiment results show that NOF removal in Ca-Ag3PO4/PMS/visible light process was higher than the sum of that in Ca-Ag3PO4/visible light and Ca-Ag3PO4/PMS processes. This significant enhancement of NOF removal was mainly due to a synergistic effect between photocatalysis of Ca-Ag3PO4/visible light process and Fenton reaction of Ca-Ag3PO4/PMS process. The inhibitory effects of water quality components on NOF removal followed: Humic acid (HA) > PO43-> HCO3−> NO3−> Cl−. NOF and co-existing heavy metals (ie., Cr(VI) and Ni(II)) or organic compounds like tetracycline (TC) could be simultaneously removed. Both PMS and H2O2 exhibit positive effects on the removal of NOF, but PMS could more effectively improve NOF removal compared with H2O2. An excellent PMS decomposition had been achieved in Ca-Ag3PO4/PMS/visible light process. HO•, SO4•− and 1O2 all took part in NOF degradation by Ca-Ag3PO4/PMS/visible light process, but both HO• and SO4•− might be primary species for NOF degradation. A plausible degradation pathway of NOF in Ca-Ag3PO4/PMS/visible light process was thereby proposed to proceed through ring-opening cracking hydroxylation and elimination reactions reactions. The enhanced reaction mechanism for the degradation of NOF in Ca-Ag3PO4/PMS/visible light process was also proposed.