Estimates of synthetic fertilizer N-induced direct nitrous oxide emission from Chinese croplands during 1980-2000

There is increasing concern that agricultural intensification in China has greatly increased N₂O emissions due to rapidly increased fertilizer use. By linking a spatial database of precipitation, synthetic fertilizer N input, cropping rotation and area via GIS, a precipitation-rectified emission factor of N₂O for upland croplands and water regime-specific emission factors for irrigated rice paddies were adopted to estimate annual synthetic fertilizer N-induced direct N₂O emissions (FIE-N₂O) from Chinese croplands during 1980-2000. Annual FIE-N₂O was estimated to be 115.7 Gg N₂O-N year⁻¹ in the 1980s and 210.5 Gg N₂O-N year⁻¹ in the 1990s, with an annual increasing rate of 9.14 Gg N₂O-N year⁻¹ over the period 1980-2000. Upland croplands contributed most to the national total of FIE-N₂O, accounting for 79% in 1980 and 92% in 2000. Approximately 65% of the FIE-N₂O emitted in eastern and southern central China.     

Spatial distribution of perfluoroalkyl acids in the Pearl River of Southern China

An intensive campaign was conducted in September 2012 to collect surface water samples along the tributaries of the Pearl River in southern China. Thirteen perfluoroalkyl acids (PFAAs), including perfluorocarboxylates (PFCAs, C4–C11) and perfluorosulfonates (PFSAs, C4, C6–C8, and C10), were determined using high-performance liquid chromatography/negative electrospray ionization–tandem mass spectrometry (HPLC/(-)ESI–MS/MS). The concentrations of total PFAAs (ΣPFAAs) ranged from 3.0 to 52 ng L⁻¹, with an average of 19 ± 12 ng L⁻¹. The highest concentrations of ΣPFAAs were detected in the surface water of the Dong Jiang tributary (17–52 ng L⁻¹), followed by the main stream (13–26 ng L⁻¹) and the Sha Wan stream (3.0–4.5 ng L⁻¹). Perfluorooctanoate (PFOA), perfluorobutane sulfonate (PFBS), and perfluorooctane sulfonate (PFOS) were the three most abundant PFAAs and on average accounted for 20%, 24%, and 19% of ΣPFAAs, respectively. PFBS was the most abundant PFAA in the Dong Jiang tributary, and PFOA was the highest PFAA in the samples from the main stream of the Pearl River. A correlation was found between PFBS and PFOA, which suggests that both of these PFAAs originate from common source(s) in the region. Nevertheless, the slope of PFBS/PFOA was different in the different tributaries sampled, which indicates a spatial difference in the source profiles of the PFAAs.     

碘掺杂Ti02可见光光催化性能研究

在低于100℃温度条件下,采用溶胶一凝胶法以钛酸正丁酯为钛源,碘酸钾为碘源,制备了I掺杂纳米TiO2催化剂（I-TiO2）,运用x-射线衍射（XRD）、透射电镜（TEM）及x-射线光电子能谱（XPS）等对催化剂进行表征,结果表明,TiO2及I-TiO2催化剂均为锐钛矿,I吸附并包裹在TiO2表面或以间隙进入的形式存在,并未进入TiO2晶格。通过在可见光照射下（A〉420nm）以罗丹明B（RhodamineB,RhB）的光催化降解为探针反应研究了在不同条件下制备催化剂的催化性能,结果表明,掺杂比为n1：n^ti=0．05：l,焙烧温度为400℃,降解介质条件pH=7时,l-TiO2光催化活性明显优于未掺杂的TiO2。光催化降解过程通过红外光谱（IR）,总有机碳（TOC）跟踪测定,比较了TiO2掺杂前后降解RhB和对氯苯酚（4-CP）的光催化特性差异;同时采用苯甲酸荧光光度法跟踪测定体系中的氧化物种,表明在可见光下,I-TiO2光催化体系中产生·OH高活性氧化物种从而氧化降解目标化合物。     

粉煤灰免烧陶粒制备及其重金属废水净化性能

摘要重金属废水对环境的污染已经引起科研人员的广泛关注。以粉煤灰和水泥为原料、添加活性成分FeS,制备一种免烧陶粒用于含重金属Cu2＋、Zn2＋、Pb2＋的废水处理。探讨了物料配比及蒸养时间对陶粒筒压强度及其比表面积的影响;研究了固液比、接触时间、pH、温度及初始溶液浓度等因素对Cu2＋、Zn2＋、Pb2＋离子净化效果的影响规律,并对实验结果进行了等温线拟合。XRD分析显示,免烧陶粒中存在Ca（OH）2、C—D—H、FeS等矿物相,对重金属离子具有非常好的固定化作用。该免烧陶粒对重金属离子具有很好的去除效果,具备较好的应用前景。     

稻秆对铜绿微囊藻抑制作用的研究

研究了稻秆浸出液对铜绿微囊藻生长的抑制作用.研究表明,稻秆浸出液中含有的化学物质抑制了铜绿微囊藻的生长繁殖.稻秆浸泡时间的延长,有利于提高浸出液的抑藻效果,但浸泡时间过长则无益于抑藻效果提高,浸泡时间为15 d时,抑制率能高达75.99%.稻秆浸出液投加量达7.5%以上具有显著的抑藻效果.不同部位的水稻秸秆浸出液对铜绿...     

Quantifying air pollution attenuation within urban parks: an experimental approach in Shanghai, China

Parks with various types of vegetations played an important role in ameliorating air quality in urban areas. However, the attenuation effect of urban vegetation on levels of air pollution was rarely been experimentally estimated. This study, using seasonal monitoring data of total suspended particles (TSP), sulfur dioxide (SO(2)) and nitrogen dioxide (NO(2)) from six parks in Pudong District, Shanghai, China, demonstrated vegetations in parks can remove large amount of airborne pollutants. In addition, crown volume coverage (CVC) was introduced to characterize vegetation conditions in parks and a mixed-effects model indicated that CVC and the pollution diffusion distance were key predictors influencing pollutants removal rate. Therefore, it could be estimated by regression analysis that in summer, urban vegetations in Pudong District could contribute to 9.1% of TSP removal, 5.3% of SO(2) and 2.6% of NO(2). The results could be considered for a better park planning and improving air quality.     

磷酸三(1,3-二氯-2-丙基)酯导致小鼠神经毒性结局的潜在靶点研究

磷酸三(1,3-二氯-2-丙基)酯(TDCPP)在环境介质及生物样本中被广泛检出,为探究TDCPP的潜在神经毒性以及作用机制,以C57BL/6小鼠为动物模型,考察经300 mg·kg-1·d-1的TDCPP持续染毒35 d后,小鼠大脑皮层神经功能相关因子及血清代谢组学的变化.结果显示,小鼠在TDCPP染毒35 d后,大...     

新型溴代阻燃剂TBB和TBPH的生态毒理研究进展

新型溴代阻燃剂2-乙基己基-四溴苯甲酸(2-ethylhexyl-2,3,4,5-tetrabromobenzoate,TBB)和2,3,4,5-四溴-苯二羧酸双(2-乙基己基)酯(bis(2-ethylhexyl)2,3,4,5-tetrabromophthalate,TBPH)作为传统溴代阻燃剂多溴联苯醚(poly...     

四川酸性物湿沉降模式及预测

酸沉降是一复杂的大气物理和化学过程，涉及诸多复杂影响因素。目前，我国酸雨湿沉降模式还仅限于模拟云下洗脱成酸过程，而对云中的成酸过程还未进行深入研究，这不仅在理论上不完善，而且更重要是在许多情况下与我省实际情况不符。本课题针对四川省特定的地理，气象特点和严重的大气污染情况，并借鉴国外研究成果，提出了考虑酸性沉降的云中和云下成酸过程和各种影响因素的综合酸雨湿沉降模式，并根据此模式来估算和预测四川省酸雨     

A WATER QUALITY‐BASED APPROACH FOR WATERSHED WIDE BMP STRATEGIES1

ABSTRACT: Watershed management strategies generally involve controlling nonpoint source pollution by implementing various best management practices (BMPs). Currently, stormwater management programs in most states use a performance‐based approach to implement onsite BMPs. This approach fails to link the onsite BMP performance directly to receiving water quality benefits, and it does not take into account the combined treatment effects of all the stormwater management practices within a watershed. To address these issues, this paper proposes a water quality‐based BMP planning approach for effective nonpoint source pollution control at a watershed scale. A coupled modeling system consisting of a watershed model (HSPF) and a receiving water quality model (CE‐QUAL‐W2) was developed to establish the linkage between BMP performance and receiving water quality targets. A Monte Carlo simulation approach was utilized to develop alternative BMP strategies at a watershed level. The developed methodology was applied to the Swift Creek Reservoir watershed in Virginia, and the results show that the proposed approach allows for the development of BMP strategies that lead to full compliance with water quality requirements.