Endosulfan in China 1—gridded usage inventories

Background, aim, and scope  Endosulfan, an organochlorine pesticide (OCP), is genotoxic in mammalian cells and generally considered to be toxic and classified by the World Health Organization and the US Environmental Protection Agency as priority pollutants and a nominator for inclusion in a future iteration of the persistent organic pollutants treaty. Endosulfan is a currently used pesticide and still being used worldwide. The general trend of total global endosulfan use has increased continuously since the first year when this pesticide was applied. It is critical to create national endosulfan usage/emission inventories for China to carry out source–receptor relation analysis, risk assessment, and other research related to endosulfan in this country. Chinese inventories have been published for some OCPs, such as technical HCH and lindane, DDT, and chlordane; for endosulfan, however, there has not been any usage inventory available on any scales (national or provincial), although endosulfan has been widely used since 1994 in this country. This is the first part of the work. The goal of this paper is to quantify the historical production and usage of endosulfan in China and to compile gridded historical usage inventories of endosulfan for this country. Based on these usage inventories, emission and residue inventories will be created, which is the goal of the second part of the work. Materials and methods  Due to the lack of national production and usage information of endosulfan in China, a method to estimate the use of endosulfan was developed. First, information of crops on which endosulfan is applied and average endosulfan use and annual application frequencies of endosulfan on these crops were collected. Secondly, usage of endosulfan on each crop was estimated using the national cropland area for each province from Chinese government reports. Finally, with the help of GIS (geographic information system), the usage data of this insecticide was allocated to a grid system, with a 1/4° longitude by 1/6° latitude resolution, with a size for each grid cell of approximately 25 km by 25 km. Results and discussion  The use of endosulfan in agriculture in China started on cotton in 1994, and on wheat, tea, tobacco, apples, and other fruits in 1998. Endosulfan usage on cotton, wheat, tea, tobacco, and apples in China has been estimated to be approximately 25,700 t between 1994 and 2004. The province with the highest usage of endosulfan is Henan Province, with a total usage reaching 4,000 t, followed by the uses in Xinjiang Autonomous Region (3,200 t), Shandong Province (3,000 t), Hebei Province (2,100 t), and Anhui Province (1,900 t). Gridded usage inventories of endosulfan at a 1/4° longitude by 1/6° latitude resolution have been created, which indicate that the intensive endosulfan use was in the south of Hebei Province, west of Shandong Province, east of Henan Province, north of Anhui Province, east of Jiangsu Province, and some areas in Yunnan Province and Xinjiang Autonomous Region. General agreement has been found between the usage data from our estimation and the small amount of usage data published in China. Conclusions  This is the first national gridded endosulfan usage inventory produced for China. The annual applications of endosulfan from 1994 to 2004 in China were estimated based on the total areas of major crops, on which endosulfan was applied, and spatial distribution of the application was generated at provincial and prefecture levels. With the help of GIS, endosulfan usage based on prefecture was transferred to a 1/4° longitude by 1/6° latitude gridding system. The satisfaction of the inventories was supported by the consistence between the estimation of the annual usage and the reported annual production of endosulfan. Recommendations and perspectives  This gridded endosulfan usage inventory created in this study will be improved upon availability of new information of endosulfan. The usage inventories can be used to create gridded emission and residue inventories for this insecticide. It is believed that this work will pave the way for further endosulfan studies in China and beyond.     

Analysis of the Energy Embodied in Foreign Goods Trade of China

In recent years, scientists have been increasingly interested in the energy embodied in traded goods among countries. In this article, the direct energy intensities in various economic sectors of China were calculated with the data of energy consumption and output value of each sector, and the input-output table was used to estimate the external energy consumption. The total energy intensity of all sectors was then obtained. From the data of international trade, the energy embodied in goods trade of China was estimated for the period of 1994-2001. During this period, the average energy intensity of imported goods was always higher than that of exported ones. As a country with a surplus in international goods trade, China actually imported net embodied energy in the past few years. The net embodied energy imported was at the same magnitude of the imported energy in the form of fossil fuels.     

CAST工艺处理低C/N生活污水的强化脱氮性能

研究了不同运行条件对CAST工艺处理低C/N实际生活污水脱氮性能的影响,并对pH值和ORP的变化规律进行了分析。结果表明,传统4 h运行模式下,提高原水C/N比,TN去除效果并无显著提高;对于低C/N生活污水,降低充水比有利于提高出水TN去除率,然而,充水比降至16%时,系统因低负荷运行发生污泥膨胀。在不投加外碳源的情况下,采用分段进水交替A/O运行模式可大幅改善系统脱氮性能,且TN去除率随着交替次数的增多而提高,交替4次平均去除率达87.23%。系统采用实时控制方式运行时,可根据有机物降解、氨氧化及反硝化时pH值和ORP曲线上是否出现拐点,来判断反应系统的曝气以及搅拌时间是否过长、适当或不足。     

化学溶胀法分离废弃线路板中金属与基板

废弃线路板的粉碎和所含金属组分的高效解离是后续分选回收的前提条件。本研究分别使用乙二胺等10种溶剂浸泡废弃线路板,比较对线路板中铜箔与基板间剥离强度的影响,从而筛选出4种有代表性的溶剂,即溶剂D、溶剂F、丙酮和水, 比较废弃线路板经化学溶胀后的单体解离度和获得一定粒径分布的颗粒所需的破碎时间。研究结果表明,化学溶胀后破碎能大幅提高金属的单体解离度,浸泡效果的优良排序为：溶剂D>溶剂F>丙酮>水;浸泡时间越长,浸泡温度越高,对剥离强度的降低越有利;使用溶剂D在150℃、3 h或140℃、5 h的工艺下浸泡废弃线路板,可以使铜箔与基板自动脱落。研究结果为后续的分选提供了便利的条件。     

复合沸石滤床修复北方景观水体的实验研究

以天然矿物质沸石、细砂及煤渣取代传统滤料构建复合基质生态床,表面种植景观植物,采用下向流-上向流运行方式修复北方景观水体。分别进行静态实验及不同循环速率下的动态实验,考察对水体污染物去除过程。结果表明,2种运行方式下对水体NH⁺₄-N去除率都在85%以上,其中以1 h为循环周期的运行方式去除率达97%,较静态提高12.8%;TN去除率最高为84%;TP去除不稳定,过程缓慢。煤渣层对NH⁺₄-N的去除效果差,硝化作用不彻底与反硝化作用的加强使下层出水NH⁺₄-N 、NO^-₂-N及NO^-₃-N浓度均高于上层。提高循环速率有利于对氮的去除。     

新型TCAS吸附树脂对水中Cd2+的吸附去除研究

通过静态吸附试验,研究一种由超分子受体化合物磺化硫杂杯芳烃（TCAS）与树脂结合的产物——新型TCAS吸附树脂对重金属Cd²⁺的吸附去除性能,并初步探讨了吸附机理。试验研究结果表明,TCAS吸附树脂对Cd²⁺的饱和吸附量为14.45 mg/g。当温度为20℃,0.5 g TCAS吸附树脂对10 mL浓度为5 mg/L的Cd²⁺溶液吸附60 min时, Cd²⁺的去除率可达到99%以上。pH值是影响TCAS吸附树脂吸附效果的重要因素,在pH=5～9时,Cd²⁺的去除率随着pH值的升高而增大。在试验范围内,TCAS吸附树脂对Cd²⁺吸附符合Freundlich方程。吸附在TCAS吸附树脂上的Cd²⁺可洗脱回收,TCAS吸附树脂也可再生利用。 TCAS吸附树脂对重金属Cd²⁺的吸附机理主要归因于TCAS对Cd²⁺的络合作用。     

电-生物耦合技术对偶氮染料的去除研究

酸性大红GR是一种较难生物降解的偶氮染料,采用一种电场和生物耦合的新型技术处理酸性大红GR模拟废水,并与单纯电化学法和好氧生物法进行试验对照。结果表明：反应6 h后,电化学法、好氧生物法、电-生物耦合技术对酸性大红GR的去除率分别达到15.7%、25.8%和71.2%,电-生物耦合技术能明显提高酸性大红GR的去除效果,起到强化生物处理的作用。在15 mA微电流条件下电-生物技术能克服50 mg/L酸性大红GR对好氧生物处理的抑制作用,为高浓度难降解染料废水的生物强化处理提供了可能。     

表面活性剂清洗处理重度石油污染土壤

为了优化表面活性剂清洗处理重度石油污染土壤的方法和具体洗脱条件参数,采集山东省东营市胜利油田污染土壤,研究了阴离子-非离子混合表面活性剂对该土壤中石油类污染物的去除效果。应用化学热洗原理,主要考查了表面活性剂配比、投加量、清洗温度及清洗助剂对去除效果的影响。实验得到的清洗处理最佳条件为：使用LAS与TX-100质量比为8∶2的组合表面活性剂,总表面活性剂浓度为3 g/L,助剂硅酸钠浓度为5 g/L,75℃条件下搅拌1 h。清洗后土壤含油量从20%下降到4.6%,去除率达到76.9%。废水回用实验表明,清洗处理的废水对土壤中石油烃类物质仍有一定的去除效果。废水回用比从30%到100%时,对土壤中石油烃的去除率都可达到55%以上。对废水进行二次回用时仍能去除18.8%的污染物。     

赭石对模拟重金属废水的吸附效果研究

采用模拟重金属废水的正交试验设计,进行赭石对模拟重金属废水的吸附效果研究,探讨pH、赭石加入量和振荡时间等影响因素对吸附效果的影响。结果表明,在一定pH、赭石加入量和振荡时间条件下,赭石对6种重金属（Pb、Cd、Mn、Zn、Cr和Ni）均有较好吸附效果,对Pb、Cd、Mn、Zn和Cr的最大吸附率可达100%,对Ni的吸附率达8963%。处理后废水中重金属达到污水排放标准。各影响因素对Mn、Zn和Cr吸附效率的影响大小表现为：pH＞赭石加入量＞振荡时间,Ni和Cd表现为：赭石加入量＞pH＞振荡时间,Pb表现为：pH＞振荡时间＞赭石加入量。赭石对废水中重金属吸附的最佳条件为赭石加入量40 g/L,pH 10～10.5,振荡时间2 h。     

利用UVC去除低浓度苯的实验研究

探讨了不同实验参数对苯的UVC去除效果的影响,获得了苯的去除率与苯的初始浓度、气体流量、相对湿度和氧气含量等参数之间的关系。数据表明,在实验条件范围内,苯的去除率的倒数与苯初始浓度、气体流量之间为线性关系;苯的去除率随相对湿度的增加呈现先升高后缓慢降低的关系,最佳相对湿度值在30%～50%之间;苯的去除率随氧气量的增加而缓慢增加;波长为185+254 nm的UV与254 nm的UV相比净化效果更为理想。还分析了苯降解产生的中间产物,探讨了苯的降解机理。