Interactions of extracellular DNA with aromatized biochar and protection against degradation by DNase I

With increasing environmental application, biochar (BC) will inevitably interact with and impact environmental behaviors of widely distributed extracellular DNA (eDNA), which however still remains to be studied. Herein, the adsorption/desorption and the degradation by nucleases of eDNA on three aromatized BCs pyrolyzed at 700 °C were firstly investigated. The results show that the eDNA was irreversibly adsorbed by aromatized BCs and the pseudo-second-order and Freundlich models accurately described the adsorption process. Increasing solution ionic strength or decreasing pH below 5.0 significantly increased the eDNA adsorption on BCs. However, increasing pH from 5.0 to 10.0 faintly decreased eDNA adsorption. Electrostatic interaction, Ca ion bridge interaction, and π-π interaction between eDNA and BC could dominate the eDNA adsorption, while ligand exchange and hydrophobic interactions were minor contributors. The presence of BCs provided a certain protection to eDNA against degradation by DNase I. BC-bound eDNA could be partly degraded by nuclease, while BC-bound nuclease completely lost its degradability. These findings are of fundamental significance for the potential application of biochar in eDNA dissemination management and evaluating the environmental fate of eDNA.     

The occurrence of per- and polyfluoroalkyl substances (PFASs) in fluoropolymer raw materials and products made in China

Perfluorooctanoic acid (PFOA), its salts, and related compounds were listed as new persistent organic pollutants by the Stockholm Convention in 2019. In this study, the occurrence of residues of PFOA and other per- and polyfluoroalkyl substances (PFASs) in raw materials and fluoropolymer products from the Chinese fluoropolymer industries are reported for the first time. The PFOA concentrations in raw materials and fluoropolymer products were in the range of 6.7 to 1.1 × 10⁶ ng/g, and <MDL (method detection limit) to 5.3 × 10³ ng/g, respectively. Generally, the levels of PFOA in raw materials were higher than in products, implying that PFOA in the emulsion/dispersion resin could be partly removed during the polymerization or post-processing steps. By tracking a company's polytetrafluoroethylene (PTFE) production line, it was found that over a 5 year period, the residual levels of PFOA in emulsion samples declined from 1.1 × 10⁶ to 28.4 ng/g, indicating that the contamination of PFOA in fluoropolymer products from production source gradually decreased after its use had been discontinued. High concentrations of HFPO-TrA (2.7 × 10⁵ to 8.2 × 10⁵ ng/g) were detected in some emulsion samples indicating this alternative has been widely applied in fluoropolymer manufacturing in China.     

海军直升机表面涂层体系改进研究

目的解决海军直升机表面涂层体系耐腐蚀性能较差,难以满足日历寿命要求的难题。方法采用新研制的有机涂层和原陆军直升机涂层分别对设计的结构模拟件进行涂装,并进行8个周期、共计200天的加速腐蚀试验,利用光泽度测量、色差测量和电化学阻抗测量的方法对涂层的腐蚀情况进行表征,考核验证涂层体系的防腐蚀性能。结果试验后新、原涂层外观基本完整,新涂层光泽度与色差无明显变化,原涂层光泽度下降较大。新涂层一直处于腐蚀初期的渗水阶段,其阻抗在10~8Ω·cm~2范围内,原涂层已进入腐蚀中期,其阻抗在10~6Ω·cm~2范围内。结论新涂层耐蚀性能更为优良,更加适用于海洋环境下的使用。     

Fe/污泥基生物炭持久活化过硫酸盐降解酸性橙G

利用污泥基生物炭（SDBC）固定铁物质制备了一种污泥基非均相催化剂（Fe-SDBC）,用于活化过硫酸盐（PS）以降解酸性橙G（OG）.Fe-SDBC/PS体系显示出对OG优异的降解性能.评价了影响降解的因素（Fe-SDBC金属负载量、Fe-SDBC投加量、初始pH值和PS浓度）.并通过X射线荧光光谱仪（XRF）、傅立叶变换红外分析仪（FT-IR）和拉曼光谱仪（Raman）对Fe-SDBC进行了表征.自由基清除剂实验表明,SO₄^·-和OH·自由基均在降解过程中生成,且活化PS历程主要发生在非均质催化剂表面.分析Fe-SDBC活化PS的潜在机理,表明不同形式的铁物质是PS分解的主要贡献者,Fe²⁺/Fe³⁺的转化循环提高了Fe-SDBC持久活化PS的效果.Fe-SDBC循环实验表明其对活化PS具有较好的可重用性,连续3次24h降解高浓度污染物仍能发挥作用.综上所述,Fe-SDBC作为一种污泥基非均相催化剂可以持久活化PS,从而实现OG的降解.     

山东省自然保护区管理状况调查与分析

基于自然保护区管理机构、人员配置、固定资产、事业经费、基建与生态工程投入、旅游收入等17项调查指标,系统调查了山东省自然保护区管理机构、人员配置和资金投入状况,定量分析了山东省自然保护区管理状况,论述了自然保护区管理存在的主要问题与对策。结果表明:山东省56%的自然保护区建立了专门的管理机构,63%的自然保护区现有人员数量低于25人,33%的自然保护区事业经费低于45万元。自然保护区管理存在的主要问题是管理机构不健全、人员配置不合理和资金投入不足。因此,山东省自然保护区管理应进一步完善管理机构,合理配置人员,增加资金投入。     

铁修饰生物炭的制备及在砷污染土壤修复中的应用

生物炭因具有较大的孔隙度、比表面积以及较强的吸附能力等优点,在环境污染修复、土壤改良和固碳方面应用广泛.由于大多数生物炭表面带有负电荷,而土壤中的无机砷主要以砷酸盐和亚砷酸盐等阴离子形式存在.因此,生物炭对砷的吸附效率通常较低,需要对生物炭进行改性以提升其对砷的吸附效果.零价铁和氧化铁等铁基材料对砷吸附能力强且来源广泛,通过沉淀法、热解法、球磨法和微生物法等方法将铁基材料与生物炭负载形成铁修饰生物炭,可将二者的优良特性相结合,拓展生物炭材料在环境修复中的应用.在对近年来有关铁修饰生物炭的文献进行系统分析的基础上,综述了常见的铁修饰生物炭的制备方法,比较分析了生物炭基底、铁修饰材料以及两者对砷的协同作用机制,并简要阐述了铁修饰生物炭在土壤污染修复中的应用现状,最后对铁修饰生物炭的未来研究方向提出了展望.     

海原地震区不同地貌单元的黄土斜坡动力响应

近年来,许多学者利用现场地震监测或数值试验来研究斜坡的地震响应,然而不同斜坡往往存在不同类型的地貌单元,其动力响应机制往往也存在很大差异。本文依托海原大地震区域,基于室内试验、现场波速测试等方法,运用有限元数值模拟技术对海原大地震影响范围内不同地貌单元的斜坡的动力响应进行了研究。结果表明：黄土塬具有高程放大效应,在同一高程水平面上,且距坡面一定范围内时越趋近坡面斜坡动力放大系数（peak ground acceleration amplification coefficient,PGA放大系数）越大;对比不同类型的地貌单元,地层结构相同的斜坡其响应规律一致,但在古土壤层其PGA放大效应会减弱。模型分析较好地揭示了人工合成地震波作用下黄土高原斜坡的动力放大效应,可为不同地貌单元地震诱发的地质灾害的风险评价和防灾减灾提供有益的借鉴与参考。     

春灌背景下黄河上游清水河流域DOM的空间分布规律

运用三维荧光光谱技术结合紫外-可见吸收光谱表征技术,以及各种分析统计方法,对清水河流域水体中溶解性有机质（DOM）的空间分布、光谱特征及污染来源进行了解析,以期为黄河流域水环境治理及污染溯源提供较为可靠的信息.结果表明清水河流域春灌季水质指标空间差异性较大.DOM中类蛋白质物质浓度高于类腐殖质物质浓度,自生源特征强于陆源特征,且新生成的DOM占比较大,即DOM主要来源于水体微生物活动和细菌降解代谢的产物.PARAFAC解析得到6个主成分,包括4个类蛋白质组分（C1、C2、C3、C5）和2个类腐殖质组分（C4、C6）,其中类蛋白质组分的空间差异性大于类腐殖质组分,受水库水和污水处理厂排水等水体内源影响较大.PCA分析得到4个主成分,组分C5、氟离子、组分C2和HIX可分别作为该4个主成分的描述性指标.     

Release of Pb adsorbed on graphene oxide surfaces under conditions of Shewanella putrefaciens metabolism

In this study, Pb(II) was used as a target heavy metal pollutant, and the metabolism of Shewanella putrefaciens (S. putrefaciens) was applied to achieve reducing conditions to study the effect of microbial reduction on lead that was preadsorbed on graphene oxide (GO) surfaces. The results showed that GO was transformed to its reduced form (r-GO) by bacteria, and this process induced the release of Pb(II) adsorbed on the GO surfaces. After 72 hr of exposure in an S. putrefaciens system, 5.76% of the total adsorbed Pb(II) was stably dispersed in solution in the form of a Pb(II)-extracellular polymer substance (EPS) complex, while another portion of Pb(II) released from GO-Pb(II) was observed as lead phosphate hydroxide (Pb₁₀(PO₄)₆(OH)₂) precipitates or adsorbed species on the surface of the cell. Additionally, increasing pH induced the stripping of oxidative debris (OD) and elevated the content of dispersible Pb(II) in aqueous solution under the conditions of S. putrefaciens metabolism. These research results provide valuable information regarding the migration of heavy metals adsorbed on GO under reducing conditions due to microbial metabolism.     

Sulfur deposition simulations over China, Japan, and Korea: a model intercomparison study for abating sulfur emission

In response to increasing trends in sulfur deposition in Northeast Asia, three countries in the region (China, Japan, and Korea) agreed to devise abatement strategies. The concepts of critical loads and source?Creceptor (S?CR) relationships provide guidance for formulating such strategies. Based on the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project, this study analyzes sulfur deposition data in order to optimize acidic loads over the three countries. The three groups involved in this study carried out a full year (2002) of sulfur deposition modeling over the geographic region spanning the three countries, using three air quality models: MM5-CMAQ, MM5-RAQM, and RAMS-CADM, employed by Chinese, Japanese, and Korean modeling groups, respectively. Each model employed its own meteorological numerical model and model parameters. Only the emission rates for SO₂ and NO_x obtained from the LTP project were the common parameter used in the three models. Three models revealed some bias from dry to wet deposition, particularly the latter because of the bias in annual precipitation. This finding points to the need for further sensitivity tests of the wet removal rates in association with underlying cloud?Cprecipitation physics and parameterizations. Despite this bias, the annual total (dry plus wet) sulfur deposition predicted by the models were surprisingly very similar. The ensemble average annual total deposition was 7,203.6?±?370 kt S with a minimal mean fractional error (MFE) of 8.95?±?5.24?% and a pattern correlation (PC) of 0.89?C0.93 between the models. This exercise revealed that despite rather poor error scores in comparison with observations, these consistent total deposition values across the three models, based on LTP group's input data assumptions, suggest a plausible S?CR relationship that can be applied to the next task of designing cost-effective emission abatement strategies.