库布齐沙漠典型地区景观变化研究

Spatial pattern analysis is the core component in landscape ecology research. We analyzed the landscape pattern and dynamic process of the Kubuqi Desert by using a typical region as a study area. This study area includes four towns: ShuLinZhao, WangAiZhao, BaiNiJing and JiGeSiTai. The area of cropland, fixed sand dune, woodland, residential area and wetland increased and centralized gradually, while the area of semi-fixed sand dune, drifting sand dune, meadow and washland decreased and dispersed gradually from 1987 to 2003. On the landscape level, the patch shape tended to be regular, and the landscape pattern tended to be simple, causing the fragmentation degree, heterogeneity and diversity of the landscape to decrease. Fixed sand dune, Semi-fixed sand dune, drifting sand dune, meadow and river flood plains were the five main export classes, and residential area, cropland and wetland were the three main import classes. The classes that had a relatively large total area and large average patch area had a smaller extent of gravity center migration, whereas the classes with small total area and small average patch area had a larger extent of gravity center migration; this is because the small patches are easily influenced by human activities or natural factors. In addition, the desertification area and desertification degree reduced gradually in the study area during the period from 1987 to 2003.     

环境中的轮胎磨损颗粒:从路面到海洋

轮胎磨损颗粒是环境中微塑料的主要来源之一,目前全球轮胎磨损颗粒的释放量在590万t·a^-1左右,约占海洋微塑料总量的15%.轮胎磨损颗粒产生于路面,通过雨水径流迁移,进而存在于路面、土壤、沉积物、水体、生物体等环境介质中.当前轮胎磨损颗粒的检测主要通过检测标记物来实现,因此,标记物的选择是关键.同时,轮胎磨损颗粒会通过吸附和浸出污染物产生污染,对人体和生物体都有一定的健康风险.对于环境中轮胎磨损颗粒的控制,最直接的方式就是在迁移路径中截留轮胎磨损颗粒和加速轮胎磨损颗粒的分解;而改进轮胎配方,降低磨损率可从源头减少轮胎磨损颗粒的释放.目前,人们对轮胎磨损颗粒的认识不足,检测方法还需要完善,其环境行为和风险评价也缺乏相关的研究.获得轮胎磨损颗粒从路面到海洋迁移的规律性认识,对于了解其生态风险和潜在污染问题十分重要.基于此,本文归纳总结了轮胎磨损颗粒的产生、检测方法、环境分布、潜在风险和缓解措施等方面的研究成果,分析了轮胎磨损颗粒研究今后应予以关注的方向.     

木贼定居对铅锌尾矿砂微生物多样性及重金属迁移转化的影响

为研究根际微生物影响木贼耐受和吸附重金属的机制,为重金属污染植物-微生物协同修复提供参考,应用化学分析方法和Illumina MiSeq高通量测序技术,对木贼定居对铅锌尾矿重金属含量、土壤微生物多样性的影响进行研究。结果表明,子囊菌、未明确分类真菌和担子菌是铅锌尾矿地土壤的优势真菌。木贼定居导致散囊菌纲、座囊菌纲丰度下降,粪壳菌纲丰度增加。Alternaria,Amorphotheca,Aspergillus为尾矿裸地中主要优势真菌,Fusarium,Chaetomiaceae-Unclassified,Calcarisporiella为木贼根际土壤主要优势真菌。变形菌门、厚壁菌门、放线菌门是研究区土壤中的优势细菌类群,Lactococcus,Bacillus,Gemmatimonas,Sulfuricaulis,Dongia,Sulfurifustis,Azoarcus,Nitrospira等是尾矿地优势细菌。有机质、全氮与真菌和细菌ace,shannon指数显著相关,重金属含量与真菌和细菌ace,shannon指数显著或极显著负相关。木贼定居提高了尾矿砂中微生物的种类和多样性,有利于有机和氮素营养成分的积累和降低重金属含量;在尾矿生态修复实践中可多引入木贼等乡土草本先锋植物,同时补充有机质和氮素营养,或引入功能微生物菌剂和接种植物共生菌等,强化生态修复效果。     

基于FBM法追踪秦皇岛海域赤潮迁移扩散

在Delft3D-FLOW模型模拟水动力的基础上,基于FBM粒子追踪法建立和验证赤潮迁移扩散模型.模拟了秦皇岛海域潮流和风生流,分析了风生流对赤潮迁移扩散的作用,对比分析了FBM法、拉格朗日法和常规布朗运动法在赤潮迁移扩散模拟中的特性,测试了模型Hurst指数的敏感性并得出其在赤潮模拟中的合理取值范围.主要结论为：①秦皇岛海域的赤潮主要随潮流的涨落而往复移动,一个涨落潮周期内赤潮的净迁移距离较小;②秦皇岛海域夏季潮流较弱,但风对赤潮迁移具有一定影响,易产生东北向风生流,导致赤潮更易往东北方向迁移;③Hurst指数较明显地影响粒子云的扩散范围,Hurst指数取0.80±0.03能比较真实地模拟秦皇岛海域赤潮的迁移扩散;④FBM法可模拟赤潮的non-Fickian扩散现象,使其模拟的粒子云扩散范围和分布形状明显优于拉格朗日法和常规布朗运动法.     

利用大型土柱自然淋溶条件下研究土壤重金属的迁移及形态转化

为研究不同重金属在土壤中的迁移和形态转化,通过分层填装土柱,在土柱0~5 cm深度范围内添加Pb、Ag、Bi、In、Sb和Sn等重金属污染土壤,并在自然条件下淋溶4 a,分析各重金属在红壤、潮土、黑土和砂土中的迁移速率及其形态组成. 结果表明:①在>30 cm深度范围内,红壤、潮土和黑土中各重金属质量分数与其相应本底值相比变化不大;与试验前土壤相比,砂土整个剖面中6种重金属质量分数均较高. ②6种重金属在4种土壤中的残留率表现为砂土<潮土<黑土<红壤;对于0～10 cm土壤中Pb的残留率,在潮土中大于Ag和Sb,在黑土中大于Ag,在红壤中大于In,在砂土中则大于Sn. ③模拟试验后残留在土柱中的重金属主要分布在土壤表层(0～30 cm),而深层(>30 cm)较少;6种重金属在红壤、潮土、黑土和砂土中的残留率平均值分别为98.0%、65.1%、65.9%和56.5%. ④与添加污染土壤之前相比,试验后土壤中残渣态等稳定形态重金属质量分数较低,其中Pb、In和Sb均以碳酸盐结合态和有机金属络合态为主,Ag和Sn分别以有机金属络合态、双氧水可提取有机结合态和有机金属络合态、无定形铁锰氧化物结合态为主,而Bi则以碳酸盐结合态和双氧水可提取有机结合态为主. 结果显示,红壤中Pb的迁移风险较低,潮土和黑土中Ag、Sb的迁移风险较高,而砂土中Sn和Sb的迁移风险需要格外关注.      

底泥扰动下藻类对不同形态磷在水体中分布的影响

研究了反复扰动与藻类共存条件下,水体中溶解性磷、颗粒态磷、生物有效磷的分布规律,并分析了颗粒物质物理化学吸附与藻类生物利用对水体中磷消失的贡献率.结果表明,扰动抑制了水体中藻类生长,叶绿素a增加量仅为3.53μg/L(初始30μg/L)和4.80μg/L(初始120μg/L),而无扰动下该值分别为21.36μg/L (初始30μg/L)和14.49μg/L (初始120μg/L).并且,溶解氧水平和pH值均低于无扰动状态.扰动导致水体中总磷和颗粒态磷显著增加,但溶解性总磷(DTP)和溶解性磷酸盐(DIP)均有所降低.对于DTP而言,扰动状态下,颗粒物质吸附占90%,而无扰动下,则降低至60%,相应地,藻类生物利用则增加至40%.无论扰动与否,BAP基本处于稳定状态,而BAPP占BAP的百分比则有所增加.扰动状态下BAPP占PP的百分比明显低于无扰动状态.这暗示了扰动对水体中磷迁移和转化的作用大于藻.     

沸石覆盖原位控制湖泊内源中等活性有机磷迁移转化

为揭示湖泊内源中等活性有机磷(MLOP)控制与释放发生机制,采用室内模拟试验,研究沸石覆盖原位控制湖泊内源MLOP迁移转化影响因子.结果表明:酸性水体促进内源MLOP迁移,碱性条件下抑制其转化,不同pH值试验水体沉积物中内源MLOP相对浓度为:[MLOP/TP]pH8>[MLOP/TP]pH7>[MLOP/TP]pH6;温度明显提高内源MLOP迁移水平,低温水体相对高温水体沉积物中内源MLOP含量较低,5℃条件下内源MLOP迁移表观量最大,其随时间迁移量呈幂函数关系,可表示为[MLOP/TP]=0.2823T0.657(R2为0.9709);好氧或厌氧条件下,内源MLOP均发生迁移,且迁移特征和影响效能高度一致,迁移平衡后好氧环境内源MLOP和厌氧内源MLOP相对浓度呈线性相关,可表示为[MLOP/TP]好氧环境=1.0884[MLOP/TP]厌氧环境 -0.0271(R2为99895);光照因子促使内源MLOP迁移,而避光和沸石粒径因素对内源MLOP迁移影响较小;底栖生物颤蚓通过爬行、摄食、掘穴、栖所建造及分泌排泄等一系列活动影响内源MLOP迁移.沸石原位控制湖泊内源MLOP迁移转化效能较弱.     

塑料管材输配水过程中有机物释放规律研究

研究了目前给水管网中常用的3种塑料管材,未增塑聚氯乙烯(uPVC),聚乙烯(PE)和无规共聚聚丙烯(PPR)管在输配水过程中有机物的释放规律.通过静态管段实验模拟给水管网中不同输配水状态,选取总有机碳(TOC)为综合评价指标,考察了不同塑料管材中有机物随时间的迁移释放特性,并分析了管材有机物释放对管网水中余氯消耗的影响.随着管材输配水次数的增加,uPVC管释放至水中的TOC浓度和TOC释放速率分别在0.03mg/L和0.04μg/(d?cm2)以下,而PE管和PPR管在输配水过程中TOC的释放浓度和释放速率在初期最大[PE: 0.19mg/L,0.25μg/(d?cm2);PPR:0.07mg/L,0.09μg/(d?cm2)],且后期递减并趋于平稳[PE:0.03~0.08mg/L,0.05~0.10μg/(d?cm2);PPR:0.01~0.03mg/L, 0.01~0.04μg/(d?cm2)].随着水力停留时间的增加,不同管材释放的有机物浓度持续升高.不同管材有机物的释放能力排序为:PE>PPR>uPVC.各管材的有机物释放特性直接影响管网水的余氯消耗特性,且管材的有机物释放量越多,管网水的余氯消耗越快.PE管的使用易引起水体有机污染问题.本研究明确了3种常用塑料管材的有机物释放规律,将进一步为与塑料管材安全性能评价相关的国家标准的修订提供理论依据.     

Enhancing soil aggregation and acetamiprid adsorption by ecofriendly polysaccharides hydrogel based on Ca2+- amphiphilic sodium alginate

Soil aggregation plays an important role in agricultural production activities. However, the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management, resulting in the loss of water, fertilizers and pesticides in soil. At present, hydrogels have been widely reported to promote the formation of soil aggregation. In this paper, amphiphilic calcium alginate (ASA/Ca²⁺) was applied to promote the formation of soil aggregation and enhance pesticide retention. Initially, an ASA was obtained through the one-pot Ugi condensation (a four-component green chemical reaction). Then, ASA/Ca²⁺ hydrogel is prepared by Ca²⁺ cross-linking. The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer, Confocal Laser Scanning Microscope (CLSM), and Transmission Electron Microscope (TEM). And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics, adsorption isotherms, and leaching. The results shown that the three-dimensional network structure of ASA/Ca²⁺ hydrogel can promote the formation of soil aggregation. Aggregate durability index (ADI) was 0.55 in the presence of ASA/Ca²⁺ hydrogel, indicating that amphiphilic hydrogel can enhance the stability of soil aggregation. The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil, and the release of acetamiprid only about 20% in the presence of ASA/Ca²⁺ hydrogel. These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation. Thus, ASA/Ca²⁺ hydrogel is likely to improve soil quality, simultaneously it can minimize the mobility of pesticides in the agricultural system.     

移动电极电除尘器除尘效率的计算

移动电极静电除尘器通过清灰刷除掉阳极板上收集的粉尘,阳极系统为移动电极（即作回转运动的集尘极）阳极板呈带条状,固定在链条上,随链轮转动。移动电极静电除尘器有效克服了困扰常规电除尘器对高比电阻粉尘的反电晕及振打二次扬尘等问题,大幅度提高了除尘效率。提供常规固定电极除尘区与移动电极除尘区联合使用的除尘器除尘效率计算公式。