沉积物金属迁移-转化的影响因素及其规律

沉积物金属的迁移-转化行为和污染风险一直是研究热点。金属污染物在人为或自然因素下进入水体,绝大部分通过沉降作用成为沉积物固定相,如此,底泥也成了河流生态系统中重要的污染源(汇)。受外界条件干扰,沉积物和上覆水体环境条件随之变化,固定的金属污染物很可能会被释放到水体中,对生态环境造成危害。通过文献研究,对金属在水环境中的主要形态,影响沉积物-金属结合物迁移-转化的环境要素及影响机制,金属的生物可利用性和污染风险进行了综述。最后提出应加强对环境参数的变化程度和金属释放的量化关系,沉积物再悬浮-金属释放的预测模型,具有长期稳定性和可持续性的底泥污染修复和控制技术方面的研究。     

Preparation of controlled nano-MgO and investigation of its bactericidal properties

Nano-MgO is a good bactericide but with strong alkalinity in water due to its rapid hydrolysis. To control its hydrolysis rate and keep its bactericidal properties, we synthesized nano-MgO microspheres using chitosan-alginate system in this study. The synthesized nano-MgO release-controlled microspheres (nMgO-RCM) were with 0.98-1.20 mm of particle sizes. Also, their embedding ratio and loading percentage was 63.52% and 12.27%, respectively. Based on the characterization results, nano-MgO was only observed on surface of the nMgO-RCM. Its release rate from the nMgO-RCM could be controlled by the chitosan-alginate system, and the observed rate constant (k_obs) increased from 0.0289 h⁻¹ to 0.0358 h⁻¹ with the increment of the dosage from 10 mg L⁻¹ to 80 mg L⁻¹. Furthermore, the nMgO-RCM could maintain pH value lower than 8.5 and colony counts less than 20 CFU mL⁻¹ for at least 120 h.     

欧洲污染物排放与转移登记制度简介

污染物排放与转移登记制度（简称PRTR制度）,是发达国家为了对化学污染物质进行更严格的管理而实行的一种管理制度。该制度起源于1984年,最早实行的是荷兰,其后美国、欧盟、澳大利亚、加拿大、韩国、日本等国家也相继实施了PRTR制度。本文着重介绍了欧盟污染物排放与转移登记制度的发展历史,并就EPER和E—PRTR进行了简单的比较。     

土壤酸沉降缓冲机制的探讨

选取南方主要酸沉降区土壤作模拟酸雨淋溶实验,分析在酸雨作用下各土壤盐基离子的淋溶特性,硅、铝元素的释放规律及淋出液的 pH值变化特点。在此基础上,对土壤酸沉降的缓冲机制进行了探讨。      

有机质含量及其组分对洱海沉积物磷吸附-释放影响

研究了洱海不同湖区沉积物有机质含量、组分及其吸附-释放磷的特征,试图揭示有机质含量及组分对沉积物磷吸附-释放行为的影响机制.结果表明,洱海沉积物磷释放潜能随着沉积物中有机质(TOM)含量的增加而增大,而沉积物磷的最大释放速率(V释,max)和最大释放量(Q释,max)随沉积物中轻组有机质(LFOM)含量的增加而增大,释放平衡时间随活性有机质(ASOM)含量的增加而缩短,磷释放强度随LFOM占TOM比例的增加而减弱.沉积物磷的最大吸附速率(V吸,max)、最大吸附量(Q吸,max)和吸附效率随沉积物TOM含量的增加而增大,吸附平衡时间随TOM含量的增加而缩短,吸附强度随ASOM含量的增加而增强,吸附-解析平衡浓度(EPC0)随ASOM含量的增加而降低.沉积物磷释放后再吸附过程中磷释放的Q释,max和再吸附的V吸,max随TOM含量的增加而增大,当TOM含量相当时,则随沉积物ASOM含量的增加而降低,再吸附强度随沉积物中LFOM含量的增加而降低.沉积物磷吸附释放容量随有机质总量的增加而增加,吸附释放平衡浓度随有机质活性的增加而降低,释放强度和速率随有机质分解程度的增加而降低,吸附强度和速率随有机质活性的增加而增加.     

A MERGE Model with Endogenous Technological Progress

We have developed a new version of the MERGE model, called MERGE-ETL, to analyse the dynamics of endogenous technological learning (ETL) in the energy system. This paper describes the basic formulation of MERGE-ETL, the solving techniques used for this model and some first numerical results in the context of policies designed to mitigate global climate changes.     

新型缓释尿素对削减温室气体、NH3排放和淋溶作用的研究

温室气体(CO₂、CH₄、N₂O)和NH₃的排放及水体污染带来的环境问题日益突出,其中,化肥的施用等农业排放是重要来源之一.本实验评价了新型缓释化肥对温室气体排放和水体污染的影响,采用密闭箱法,在饱和田间持水量(WFPS) 60%的条件下,检测恒温(23℃)环境中土壤温室气体(CO₂、CH₄、N₂O)和NH₃挥发.结果表明,30 d内缓释尿素组比普通尿素组释放的CO₂、CH₄、N₂O平均排放通量分别降低24.69%、3.01%、26.75%,NH₃排放量减少24.36%;模拟降雨条件的淋溶实验(15 d)显示,缓释尿素组的淋失率明显低于普通尿素组,总氮减少6.97%,尿素氮减少4.75%,缓释尿素和普通尿素组淋出水样中尿素氮和总氮量所占比重均在淋溶第1 d最大,缓释尿素组尿素氮和总氮量分别为36.1%和41.23%,普通尿素组尿素氮和总氮量分别为48.7%和72.4%.结果表明,缓释尿素较普通尿素在消减温室气体排放和氨排放有明显的效果.     

提升水库下游河流水质的生态放流量确定和可行性分析

大型水利枢纽工程在防洪、发电、供水、航运等诸多方面发挥巨大作用的同时,也改变了河流的天然水文情势,导致下游河流流量减少,削弱了河流水体的自净能力,威胁河流生态系统功能和物种多样性.在此背景下,选定松辽流域石头口门水库及其下游饮马河为研究对象, 首先分析了饮马河主要污染组分COD和NH₃-N浓度的变化趋势以及前期石头口门水库的生态放流措施对下游河流水环境质量的改善效果,然后基于河流水动力和水质模型,通过目标水质反推水库的生态放流量,从而拟定了一套进一步提升河流水环境质量的水库生态放流方案.最后基于水库均衡分析论证了方案的可行性.研究结果表明,原有的水库生态放流计划实施后,劣V类水体同比减少54.55%,效果较为明显.为了满足“十四五”水质目标,进一步提升河流水质,除10月和12月以外,其它月份的生态放流量均需要提高,年生态补水量增加1425万m³,能够满足水库的供水、灌溉需求和蓄水计划,方案具有可行性,能够有效缓解河流水体污染,提升水质.     

医用电气设备电源变压器的过载试验

采用电阻法测量医用电气设备电源变压器过载试验时的绕组温升,试验电流和试验时间的选取与熔断器、过流释放器、热断路器等保护装置有关。     

Phosphorus speciation and effects of environmental factors on release of phosphorus from sediments obtained from Taihu Lake,Tien Lake,and East Lake

Phosphorus is considered the primary nutrient limiting eutrophication. The release of phosphorus from sediments not only provides hydrophytes with essential nutrients, but can also produce entrophication in lakes. In this study, the sediment characteristics, phosphorus speciation, and environmental factors affecting phosphorus release from sediments from Taihu Lake, Tien Lake, and East Lake were investigated. The results indicated that phosphorus levels of sediments ranged from 647 ± 67 to 2343 ± 122 mg/kg. Inorganic phosphorus comprised the majority of total phosphorus. The main phosphorus speciation of sediments obtained from Taihu Lake and Tien Lake was Residual-P, and the main phosphorus speciation of sediment obtained from East Lake was NaOH-P. Phosphorus release occurred in acidic and alkaline conditions but more frequently under alkaline conditions. The amount of phosphorus released from the sediments increased as the disturbing intensity rose. In addition, less phosphorus was released in natural than anaerobic conditions. The amount of phosphorus released was elevated as temperature increased.