STUDY OF THE LAW AND INFLUENCE FACTORS OF WINTER FREEZE INJURY IN GUANGXI

Thetemperatureiscrucialenvironmentalconditionforcrop'sgrowthandtoohighortoolowtemperatureisharmfultocrop'sgrowth.Guangxiliesinthetransitionbeltbetweensubtropicalareaandtropicalareawheretherearefavourableconditionsforplantingcropsandfruitsofsubtropicalandtropicalareas.Especially,inrecentyearswiththeeconomicdevelop mentofcountryandlargelyplantingoffruitsandanti seasonalvegetables,Guangxihasbecomemainfruits producingareaandcrops producingareaintropicalandsubtropicalareas.Thein vadingofcoldwaveinw…     

面向寒冷地区城镇污水处理厂提标改造的ASM模拟优化及其应用

为指导和支撑寒冷地区城镇污水厂升级改造,采用GPS-X软件的ASM1模型,构建了河北某污水处理厂CASS工艺提标改造模型,分别对污泥回流比(R_S)、反应区体积比(R_V)、充水比(λ)、运行周期(T)和不同水温的CASS运行方案等进行了数值模拟优化;同时,综合模拟结果,提出了升级改造技术方案,并予以实施。冬季运行结果表明,改造后的CASS工艺出水指标COD、氨氮和TN的浓度分别为(23.23±2.76)、(1.16±0.76)、(9.83±1.4) mg·L~(-1),能够稳定达到《城镇污水处理厂污染物排放标准》(GB 18918-2002)一级A标准。     

麦秆黄原酸酯对水中Cu(II)的吸附

采用农业废弃物麦秆为原料制备黄原酸酯,通过傅立叶变换红外光谱FT-IR、扫描电子显微镜SEM等技术对麦秆黄原酸酯物理化学性质进行表征,并对水中Cu2+进行吸附特性研究,考察了不同条件对Cu2+吸附效果的影响,并将其应用于跌水式吸附法对含重金属沼液进行处理,为麦秆黄原酸酯应用于实际污水处理提供理论参考。结果表明,麦秆黄原酸酯对Cu2+的吸附行为符合伪二级动力学吸附模型与Langmuir等温吸附方程,298 K时,Cu2+的饱和吸附量为28.33 mg/g,溶出率为4.97%,对Cu2+的固持能力较强;黄原酸酯跌水吸附法对于含量为50 mg/L以下的Cu2+废水去除率达到80%以上,对实际沼液中Pb、Zn、Cd、Cu的去除率为44.42%~90.16%,去除顺序为Cd>Pb>Cu>Zn。     

大田条件下施加组配改良剂对蔬菜吸收重金属的影响

通过向湘南某矿区周边重金属污染的农田施加不同添加量(0、2、4和8 g/kg)的组配改良剂HS(海泡石+石灰石),分析农田土壤理化性质变化和土壤重金属及其交换态含量的影响、空心菜和辣椒可食部位和根部位重金属含量的影响。结果表明,施用2~8 g/kg组配改良剂HS能使2种蔬菜土壤p H值和CEC含量显著增加,使交换态重金属含量大幅降低,且不同程度地降低了空心菜和辣椒可食部位及根部位的重金属含量。与对照相比,空心菜和辣椒可食部位重金属Pb、Cd、Cu、Zn的降幅分别为:21.1%~47.5%、6.5%~31.0%、57.7%~80.0%、65.3%~92.0%和27.3%~74.5%、29.8%~62.0%、55.4%~76%、37.8%~77.1%;根部位的重金属含量也有明显降低。当添加量为8 g/kg时,2种蔬菜可食部位和根部位重金属含量降低幅度最大。由此可知,组配改良剂HS的施用对2种蔬菜吸收土壤重金属起到有效的抑制作用。     

欧美农药环境降解动力学评估方法比较

农药在环境中的降解行为是评估农药环境安全性的基础,农药的降解动力学通常以一级动力学模型描述。现有的环境暴露模型也均需要输入一级动力学模型的农药在土壤中50%消失时间(DT50)。但有时一级动力学模型不适用于描述农药在环境中,特别是土壤中的降解。因此欧盟和北美自由贸易区已发布了一系列关于使用非一级动力学模型计算DT50的导则。介绍了欧美降解动力学评估方法,并用多组降解数据比较了2种评估方法的区别。     

微生物菌剂和鸡粪对蔬菜废弃物堆肥化处理的影响

由于我国缺乏适用的蔬菜废物循环利用技术,致使蔬菜产地的生产废物难以处理与再循环利用而被弃置。为获得适用的蔬菜废物堆肥化处理技术,本研究以小麦秸秆为水分调理剂,并分别以鸡粪和微生物菌剂为接种剂,在初始物料含水率65%和C/N为25的条件下,设置了V1(蔬菜残体+小麦秸秆)、V2(V1+鸡粪)、V3(V2+微生物菌剂)和V4(V1+微生物菌剂)等4个处理,通过测定4个不同堆肥处理对温度、含水率、C/N比以及发芽指数(GI)等指标的影响。结果表明:同时加入微生物菌剂和鸡粪的处理(V3)可使堆肥最高温度达到67.5℃,且水分脱除效果最好,最终产品的含水率是最低的;鸡粪也是较好的接种剂,提升堆肥温度且能缩短堆肥周期;发芽率指数(GI)的结果显示,4个处理之间的堆肥腐熟成度为V3>V4>V2>V1,这进一步表明,添加微生物菌剂和鸡粪可降低堆肥产品对后茬植物发芽和生长的不良抑制。     

硅烷化改性MCM-41负载戊二酸锌催化CO2与环氧丙烷共聚制备可降解材料

以三甲基氯硅烷(TMCS)为硅烷化试剂,对MCM-41分子筛进行表面改性处理,并以此为载体制备负载型戊二酸锌催化剂(ZnGA/TMCS-MCM-41);采用红外光谱、氮气吸附-脱附和X射线衍射等分析手段对催化剂进行表征,结果表明:三甲基氯硅烷基团被成功接枝到MCM-41分子筛表面,形成比表面积略低的硅烷化MCM-41载体,但其骨架未被破坏,负载活性物质过程中,戊二酸锌能以更小的粒径均匀分散到载体的表面;聚合反应实验表明,与单纯戊二锌催化剂相比,ZnGA/TMCS-MCM-41催化剂对CO2与环氧丙烷(PO)的共聚反应显示出更高的催化效率和更快的反应速度,在反应34 h后催化效率达到86.3 g聚合物/g ZnGA;红外光谱和核磁分析表明所得共聚产物中碳酸酯结构含量大于95.8%。     

Responses of CH(4), CO(2) and N(2)O fluxes to increasing nitrogen deposition in alpine grassland of the Tianshan Mountains

To assess the effects of nitrogen (N) deposition on greenhouse gas (GHG) fluxes in alpine grassland of the Tianshan Mountains in central Asia, CH₄, CO₂ and N₂O fluxes were measured from June 2010 to May 2011. Nitrogen deposition tended to significantly increase CH₄ uptake, CO₂ and N₂O emissions at sites receiving N addition compared with those at site without N addition during the growing season, but no significant differences were found for all sites outside the growing season. Air temperature, soil temperature and water content were the important factors that influence CO₂ and N₂O emissions at year-round scale, indicating that increased temperature and precipitation in the future will exert greater impacts on CO₂ and N₂O emissions in the alpine grassland. In addition, plant coverage in July was also positively correlated with CO₂ and N₂O emissions under elevated N deposition rates. The present study will deepen our understanding of N deposition impacts on GHG balance in the alpine grassland ecosystem, and help us assess the global N effects, parameterize Earth System models and inform decision makers.     

地表水环境非点源污染研究

地表水环境的非点源污染已越来越受到人们的重视。在阐述非点源污染的概念、危害性的基础上,对国内外地表水环境非点源污染研究现状进行综述。分析了国内外研究存在的不足。讨论了地表水环境非点源污染研究的未来发展趋势     

Effects of climate change and anthropogenic activity on ranges of vertebrate species endemic to the Qinghai–Tibet Plateau over 40 years

Over the past 40 years, the climate has been changing and human disturbance has increased in the vast Qinghai–Tibet Plateau (QTP). These 2 factors are expected to affect the distribution of a large number of endemic vertebrate species. However, quantitative relationships between range shifts and climate change and human disturbance of these species in the QTP have rarely been evaluated. We used occurrence records of 19 terrestrial vertebrate species (birds, mammals, amphibians, and reptiles) occurring in the QTP from 1980 to 2020 to quantify the effects of climate change and anthropogenic impacts on the distribution of these 4 taxonomic groups and estimated species range changes in each species. The trend in distribution changes differed among the taxonomic groups, although, generally, ranges shifted to central QTP. Climate change contributed more to range variation than human disturbance (the sum of the 4 climatic variables contributed more than the sum of the 4 human disturbance variables for all 4 taxonomic groups). Suitable geographic range increased for most mammals, amphibians, and reptiles (+27.6%, +18.4%, and +27.8% on average, respectively), whereas for birds range decreased on average by 0.9%. Quantitative evidence for climate change and human disturbance associations with range changes for endemic vertebrate species in the QTP can provide useful insights into biodiversity conservation under changing environments.