Charging versus exclusion: Choice between recreation management tools

Overuse of recreation sites seems to justify regulation, and the principal tools for this are fee charging or physical exclusion. Both seem equally costly to administer. Both involve equal costs to consumers if recreationists visit from one origin, but if they come from different origins, costs may be greater and consumers' surplus less under either tool, depending on the shape of the demand curve. Which is the more equitable tool depends on the relative representation of rich and poor participants from near and distant origins. Potentially beneficial use of site revenues is an advantage of charging. Neither availability of substitutes nor variation in daily demand seems likely to change these results substantially, but a system of booking admissions before the trip outset might neutralize the advantages of charging. The optimal level of use varies with the regulatory tool chosen. The optimal admissions under exclusion could be fewer than or more than under charging, or may even be equal to unregulated use.     

Design of Mass Exchange Network and Effluent Distribution System for effective water management

The environmental impact of industrial wastewater and higher cost of fresh water are the serious challenges faced by the process industries. It has led to the development of many new techniques to minimize fresh water consumption. Of the many approaches, which have been developed, the Water Source Diagram (WSD) is a flexible and dynamic alternative for the generation of different scenarios for the management of water networks with reduction in total consumption. In the present study WSD concept was coupled with water mains concept to mains simplify the piping network and reduce the cost. A new procedure was developed for integrating the effluent treatment processes to evolve Effluent Treatment Network. Example from literature having multi contaminants was considered. This simple procedure involving hand calculations will be a useful tool for process engineers to design water and effluent treatment networks. Also the WSD and ETN were combined to form an evolutionary WAMEN (Water Allocation and Mass Exchange Network) and the proposed WAMEN aims for minimum fresh water consumption.     

第二松花江中下游水体中苯系物含量及分布特征

本次研究采用气质联用仪分析第二松花江中下游江段底泥和水中苯、甲苯、乙苯和二甲苯的含量,并对其分布特征和成因进行了讨论。研究发现,水中苯系物含量均远低于我国地表水环境质量标准和美国国家一级饮用水标准的限值。与国内其他水体相比,第二松花江江水中苯系物含量水平较低。底泥中苯系物含量显著高于水中,市区江段水和底泥中苯系物含量普遍高于非市区江段。     

常见茶叶氟含量的聚类分析及氟安全性探讨

用氟离子选择电极法测定10种茶叶的含氟总量及水溶性氟含量。并利用聚类分析的方法对含氟总量及浸出率进行了研究。结果表明茶叶的含氟量差异较大,受产地,茶叶制作工艺影响呈现类别性。同时可溶性氟含量除了与含氟总量正相关,还随比表面积的增大,浸泡时间的增加而增大。浸泡次数的增加而减少。     

Pollution characteristics of 15 gas- and particle-phase phthalates in indoor and outdoor air in Hangzhou

Phthalate esters (PAEs), typical pollutants widely used as plasticizers, are ubiquitous in various indoor and outdoor environments. PAEs exist in both gas and particle phases, posing risks to human health. In the present study, we chose four typical kinds of indoor and outdoor environments with the longest average human residence times to assess the human exposure in Hangzhou, including newly decorated residences, ordinary residences, offices and outdoor air. In order to analyze the pollution levels and characteristics of 15 gas- and particle-phase PAEs in indoor and outdoor environments, air and particulate samples were collected simultaneously. The total PAEs concentrations in the four types of environments were 25,396, 25,466.8, 15,388.8 and 3616.2?ng/m³, respectively. DEHP and DEP were the most abundant, and DMPP was at the lowest level. Distinct variations in the distributions of indoor/outdoor, gas/particle-phase and different molecular weights of PAEs were observed, showing that indoor environments were the main sources of PAEs pollution. While most PAEs tended to exsit in indoor sites and gas-phase, the high-molecular-weight chemicals tended to exist in the particle-phase and were mainly found in PM_2.5. PAEs were more likely adsorbed by small particles, especially for the indoor environments. There existed a good correlation between the particle matter concentrations and the PAEs levels. In addition, neither temperature nor humidity had obvious effects on the distributions of the PAEs concentrations.     

Distribution characteristics and indicator significance of Dechloranes in multi-matrices at Ny-Ålesund in the Arctic

In recent years, Dechloranes have beenwidely detected in the environment around the world. However, understanding and knowledge of Dechloranes in remote regions, such as the Arctic, remain lacking. Therefore, the concentrations of 5 Dechloranes in surface seawater, sediment, soil, moss, and dung collected from Ny-Ålesund in the Arctic were measured with the concentrations 93 pg/L, 342, 325, 1.4, and 258 pg/g, respectively, which were much lower than those in Asian and European regions. The mean ratios of anti-Dechlorane Plus (DP) to total DP (f_anti) in seawater, sediment, soil, moss, dung, and atmospheric samples were 0.36, 0.21, 0.18, 0.27, 0.66, and 0.43, respectively. Results suggested that the main source of DP in seawater, sediment, soil, andmosswas long-range atmospheric transport. However, the ratio identified in dung was different, for which the migration behavior of the organism is probably themain source of DP.     

Distribution characteristics and indicator significance of Dechloranes in multi-matrices at Ny-Ålesund in the Arctic

In recent years, Dechloranes have been widely detected in the environment around the world. However, understanding and knowledge of Dechloranes in remote regions, such as the Arctic, remain lacking. Therefore, the concentrations of 5 Dechloranes in surface seawater, sediment, soil, moss, and dung collected from Ny-Ålesund in the Arctic were measured with the concentrations 93 pg/L, 342, 325, 1.4, and 258 pg/g, respectively, which were much lower than those in Asian and European regions. The mean ratios of anti-Dechlorane Plus (DP) to total DP (?_anti) in seawater, sediment, soil, moss, dung, and atmospheric samples were 0.36, 0.21, 0.18, 0.27, 0.66, and 0.43, respectively. Results suggested that the main source of DP in seawater, sediment, soil, and moss was long-range atmospheric transport. However, the ratio identified in dung was different, for which the migration behavior of the organism is probably the main source of DP.     

微塑料及卤代有机污染物在洞庭湖的赋存研究进展

洞庭湖是中国第二大淡水湖,其生态价值十分重要。目前洞庭湖新污染物相关研究比较缺乏,也没有系统的综述进行归纳总结。微塑料和卤代有机污染物是近年来备受关注的新污染物,搜集历年研究成果,对这2类污染物在洞庭湖的污染水平、分布方式、污染来源进行归纳总结：洞庭湖微塑料污染水平在世界范围内处于中等,其主要来源包括上游输入、居民日常生活、农业生产及工业生产,湖泊各区域微塑料污染水平差异明显。卤代有机污染物在洞庭湖的浓度呈现随时间推移而降低的趋势,目前整体生态风险较低,但生物累积效应仍然值得警惕。在未来研究中应当关注河流与湖泊之间的相互影响,探究微塑料和卤代有机污染物对洞庭湖区生物造成的生物毒性,建立科学完善的监测方法并结合湖区具体情况对污染防治措施及污染物处理技术开展研究。     

顶空气相色谱分析原理与技术

系统讨论了静态顶空气相色谱的原理,包括多次相平衡法、改变相比法和标准加入定量法。测定了挥发性有机物在气液两相间的分配常数及其在水中的含量。提出了通过测定分配常数作为分析准确度的判据。研究了温度、相比、分配常数和无机盐对顶空分析灵敏度的影响。采用顶空色谱测定了河流底泥中的可酸挥发硫化物。