油码头溢油风险防控措施研究

油码头生产过程中的溢油事故隐患主要集中在码头(泊位)、油品罐区、输运船舶及输油管道4个单元,文章通过查找和研究相关法律、法规、标准及规范等关于油码头溢油风险防控的要求,对不同类型的溢油事故提出了有针对性的风险防控措施,明确了油码头在溢油风险监督管理工作中应关注的重点,从而为油码头企业开展溢油风险防控措施自查提供参考。     

中国农村饮用水水源地水质状况研究

为了系统评估中国农村饮用水水源地水质变化情况,根据2009—2018年农村饮用水水源地水质监测数据,综合评价和分析了中国农村地表和地下饮用水达标情况、空间分布和主要超标因子等。监测结果表明：10年来,农村饮用水水源地达标率不断提高,这主要得益于地表饮用水水质整体改善;地下饮用水水质达标率持续偏低,且略有变差趋势,与城市地区的差距逐年加大。农村饮用水水源地超标断面和点位在空间上分布较广,主要超标因子相对集中,且表现出与农村和农业面源污染较强的相关性。建议进一步重视农村饮用水水源地（特别是地下饮用水）的保护,加强农村饮用水水源地水质监测,加快农业面源污染防治。     

新型太阳能单相光伏逆变器应用性能研究

为提升太阳能光伏并网发电向电网输送电流的质量,对新型太阳能单相光伏逆变器的应用性能展开研究。通过分析太阳能光伏发电的构成情况,创建包含太阳能光伏电池、逆变器、Boost DC/DC电路及操控电路的单相光伏并网系统,对系统核心部分的并网逆变器进行设计,选用LLCL型滤波器降低逆变器输出电流内的谐波分量并衰弱开关频率位置的高次谐波,通过加入电网电压前馈控制的方式消除电网电压对并网电流的干扰,并结合网侧电流外环PI控制对电流内环进行控制,提升整体系统稳定性。仿真实验结果表明,采用所研究逆变器的新型太阳能单相光伏并网系统具有较好的动态性能,滤波性能优越,输出并网电流稳定,说明该逆变器应用性能好。     

改进分光光度法测Ni以规避大量干扰离子

为测定含大量干扰离子的水样中镍的浓度,提出一种改进的分光光度法。即以多种物质的吸光曲线回归方程,将实时测得的水样吸光度分解成多种物质的吸光度,利用多元一次方程进行求解并计算出浓度的方法。新方法在不进行修正时,对含Cr6+干扰的水样Ni2+测定的结果,误差较小。多组分的水样测量吸光度误差较大,通过引入修正系数修正后误差大幅下降。方法中Ni2+、Fe3+的吸光度与显色时间基本无关;而对于Mn2+、Cu2+和Cr6+,显色时间应控制在0.5～2.5 min内或10 min外,以保证测得吸光度值的稳定与准确。对组成不同的含Mn2+和Fe3+水样测得的Ni2+浓度分析,变异系数(CV)4.74%,检出限为0.275 mg/L,精确度和精密度较好。同时,这种规避方法还具有其他作用,可以在分析组分的同时粗略算出含量。     

Ice phase as an important factor on the seasonal variation of polycyclic aromatic hydrocarbons in the Tumen River,Northeastern of China

Background, aim and scope  

The climatic characteristic is a major parameter affecting on the distribution variation of organic pollutants such as polycyclic aromatic hydrocarbons (PAHs). The Tumen River is located in Northeastern of China. The winter era lasts for more than 5 months in a year, and the river water was frozen and covered by ice phase. Coal combustion is an essential heating source in the Tumen River Basin. The objective of this research is to study ice phase effect on the seasonal variation of PAHs in the Tumen River environment.     

流态化TiO2光催化降解甲苯的实验

在自制的流化床反应器中,以实验室制备的TiO2/硅胶为催化剂,对甲苯、空气混合气进行光催化降解,探讨了初始浓度、紫外光强度、操作气速和床层高度等因素对甲苯降解率的影响。实验结果表明:在低浓度范围内(20~55mg/m3),甲苯降解率不随浓度变化,高达100%,但浓度进一步增加后降解率下降;甲苯降解率随紫外光强度的增加而提高,但提幅不大;甲苯初始浓度越低,维持最高降解率的时间越长;操作气速存在最佳值3·98cm/s,达到此值时降解效果最好;甲苯降解率随床层高度(静态高度)的增加而线性提高。     

黄河三角洲自然保护区国土空间变化遥感监测与评价

为了解人类活动对黄河三角洲国家级自然保护区生态环境的影响,利用2000年至2019年的卫星影像数据,分析了黄河三角洲自然保护区近20年来土地利用的变化情况,并利用开发干扰指数定量分析了土地利用变化对自然保护区的影响。得出主要结论如下:黄河三角洲自然保护区近20年土地利用变化明显,草地、耕地和未利用地等土地利用面积下降,而建设用地（城乡居民点、工矿用地）和水域湿地等面积增加。变化面积占自然保护区总面积的47.0%,减少的草地和耕地等主要转为建设用地、水域湿地,主要表现为实验区内盐田和养殖塘面积的增加。2000年以来黄河三角洲自然保护区开发干扰指数逐年增大,2005年之前人类活动干扰相对轻微;2005年至2016年人类活动干扰剧烈,自然保护区开发干扰指数增加迅速,以盐田和养殖塘的开发为主要影响因素;2016年后自然保护区的监督管理力度加大,开发干扰指数趋于稳定。人类活动干扰呈现从轻微到剧烈再到稳定的过程。     

微塑料污染防治国际实践及对我国的启示

微塑料作为一类新污染物,已成为国际社会普遍关注的热点环境问题。欧美国家微塑料污染防治工作启动较早,具有丰富的实践经验,这对完善我国微塑料污染防治体系具有重要的借鉴意义。从制度建设、国际合作、监测评估、科学研究等方面梳理了国际社会微塑料污染防治的先进做法和实践经验,对比我国开展微塑料污染防治的相关政策和举措,分析了存在问题和短板;在此基础上,从强化顶层设计、健全协调机制、完善监测体系、重视科技支撑和加大宣传教育5个方面提出了对我国微塑料污染防治的启示。     

Pollution sources and occurrences of selected persistent organic pollutants (POPs) in sediments of the Mekong River delta, South Vietnam

The Mekong River delta is one of the largest agricultural land in the Southeast Asia. It plays a very important role for agriculture and fisheries in South Vietnam. However, comprehensive studies on the environmental pollution of persistent organic pollutants (POPs) in Mekong River delta have not been carried out in recent years. In this study, we collected sediment samples from the Mekong River to evaluate the contamination and ecological risks caused by several POPs. The contamination pattern of POPs was DDT>PCBs>CHLs>HCHs>HCB. DDTs are the most abundant pollutants, their concentration ranging from 0.01 to 110 ng/g dry wt, followed by PCBs (0.039-9.2 ng/g dry wt). DDTs and PCBs concentrations were higher in sediment from adjacent to urban areas than those from rural and agricultural sites, suggesting urban areas as important point sources of DDTs and PCBs to the river. Ratio of p,p'-DDT/p,p'-DDE was lower compared to those previously reported. However, some samples still had the ratio higher than 0.5, indicating recent input of DDT into the aquatic environments. This result shows that although the magnitude of contamination decreased over time, recent inputs of DDTs to the river still occur. Some sediment samples had concentrations of DDT compounds higher than the standards from the Canadian Environmental Quality Guideline, suggesting continuous monitoring for POPs contamination in the Mekong River is necessary.     

A New Method for Determination of Chlorophylls in Freshwater Algae

A new method (NMM, using acetic acid fiber filter and 90% ethanol) was established to determine chlorophyll in freshwater algae, and it was compared with US standard method (USM, using glass fiber filter and 90% acetone) and the method recommend by EPA of China (CHM, using acetic acid fiber filter and 90% acetone). The precision and repeatability of NMM is equivalent to that of USM, but NMM is safer to laboratory workers than USM and CHM because ethanol was used as solvent in NMM instead of acetone used in USM and CHM, and time and money were also greatly saved by the new method. The precision and repeatability of CHM was much less than USM and NMM, and the advice improving the method was proposed that the extraction time must be prolonged.