Arbuscular mycorrhizal fungus-induced decrease in nitrogen concentration in pore water and nitrogen leaching loss from red soil under simulated heavy rainfall

Environmental Science and Pollution Research - Arbuscular mycorrhizal fungus (AMF) is generally colonized in plant roots and influences the migration of mineral elements such as nitrogen (N) in...     

近30年来长江口北支及口外沉积特征及输移趋势

近30 a来长江口北支在自然和人类活动影响下，沉积物特征及输移趋势发生显著变化。研究基于2015年和20世纪80年代沉积物粒度调查资料，通过粒度对比、趋势分析等方法，探讨长江口北支及口外沉积特征与输移趋势。结果表明：长江口北支及口外沉积物类型以粘土质粉砂、砂质粉砂和砂为主，近30 a来平均中值粒径减小20%左右。其中，北支口内粒径减小约30%，表明北支口内整体为淤积环境；口外0~10 m水深区域粒径增加约25%，表现为风浪和潮流作用下的侵蚀特征；10 m水深外，粒径略有减小，沉积特征基本稳定。从沉积物输移趋势上看，北支崇头至灵甸港河段，沉积物较粗，以径流作用下的沉积为主；灵甸港至三条港河段，沉积物输移趋势向下指向三条港，其中灵甸港至三和港河段边滩粗、主槽细，径潮流交汇作用明显；三条港以下河段，沉积物以海域来沙为主，颗粒细，输移趋势指向上游；北支口外，0~10 m水深区域，沉积物粗化，沉积物随水深增加变细，其中0~2 m水深区域，砂含量占比超过90%；10 m以深离岸水域，沉积物输移趋势不显著。流域来沙减少和北支围垦工程建设，致使沿岸泥沙补给不足，口外浅滩泥沙在风浪和潮流作用下，一部分随涨潮流向口内输运，一部分随落潮流向外海扩散，构成北支及口外沉积物输移趋势格局。     

催化裂化废催化剂对废水中镉的吸附研究

本文以石油催化裂化废催化剂作为废水中镉的吸附剂，探讨了吸附时间、温度、ｐＨ值、吸附剂用量对吸附效果的影响。吸附平衡试验结果表明，废催化剂对镉的吸附属单分子层吸附，吸附较易进行，吸附过程可用Ｌａｎｇｍｕｉｒ模式和Ｆｒｅｕｎｄｉｃｈ模式较好地描述。     

室内装修造成的室内环境污染及其防治

介绍了室内环境污染的来源和建筑材料的污染性,分析了室内装修造成室内环境污染的各种因素,提出了解决问题的对策.大力推广提倡使用新型环保节能建材,对环保绿色建材的评选要本着对老百姓负责的态度严格要求,严格把关,让真正的绿色新型环保建材应用于室内装修.     

Significant tipping points of sediment microeukaryotes forewarn increasing antibiotic pollution

Antibiotic pollution imposes urgent threats to public health and microbial-mediated ecological processes. Existing studies have primarily focused on bacterial responses to antibiotic pollution, but they ignored the microeukaryotic counterpart, though microeukaryotes are functionally important (e.g., predators and saprophytes) in microbial ecology. Herein, we explored how the assembly of sediment microeukaryotes was affected by increasing antibiotic pollution at the inlet (control) and across the outlet sites along a shrimp wastewater discharge channel. The structures of sediment microeukaryotic community were substantially altered by the increasing nutrient and antibiotic pollutions, which were primarily controlled by the direct effects of phosphate and ammonium (−0.645 and 0.507, respectively). In addition, tetracyclines exerted a large effect (0.209), including direct effect (0.326) and indirect effect (−0.117), on the microeukaryotic assembly. On the contrary, the fungal subcommunity was relatively resistant to antibiotic pollution. Segmented analysis depicted nonlinear responses of microeukaryotic genera to the antibiotic pollution gradient, as supported by the significant tipping points. We screened 30 antibiotic concentration-discriminatory taxa of microeukaryotes, which can quantitatively and accurately predict (98.7% accuracy) the in-situ antibiotic concentration. Sediment microeukaryotic (except fungal) community is sensitive to antibiotic pollution, and the identified bioindicators could be used for antibiotic pollution diagnosis.     

Spatio-temporal patterns and driving forces of urban land expansion in China during the economic reform era

Along with its economic reform, China has experienced a rapid urbanization. This study mapped urban land expansion in China using high-resolution Landsat Thematic Mapper and Enhanced Thematic Mapper data of 1989/1990, 1995/1996 and 1999/2000 and analyzed its expansion modes and the driving forces underlying this process during 1990-2000. Our results show that China's urban land increased by 817 thousand hectares, of which 80.8% occurred during 1990-1995 and 19.2% during 1995-2000. It was also found that China's urban expansion had high spatial and temporal differences, such as four expansion modes, concentric, leapfrog, linear and multi-nuclei, and their combinations coexisted and expanded urban land area in the second 5 y was much less than that of the first 5 y. Case studies of the 13 mega cities showed that urban expansion had been largely driven by demographic change, economic growth, and changes in land use policies and regulations.     

内、外循环EGSB反应器酸碱调控能力的对比试验研究

通过对比运行试验,研究了内、外循环EGSB反应器酸碱特征及其调控能力.结果表明,内、外循环厌氧反应器内部的pH值分布规律相似,较低有机负荷时pH值梯度变化较小,较高负荷时随循环比变化pH值分布有所差别,但2种条件下循环比为3时反应器内pH值均可达到较均衡的分布.相同原水pH值条件下外循环体系pH值要高于内循环体系pH值,2种条件下体系pH值变化趋势较为一致,二者平均差值在0.5个单位左右.循环厌氧反应器系统pH值维持在6.3～6.8可以较好地保障系统正常运行,为了保证此条件,外循环运行方式对原水pH值的极限调节范围是4.5～6.8,内循环运行方式对原水pH值的极限调节范围是5.3～7.2.该成果对于研究和应用内外循环EGSB反应器具有理论参考和实用价值.     

中文智能型pH线监控仪及其工程应用

介绍了以微计算机为核心的中文智能型pH在线监控仪的软硬件结构、系统配置模式,及多个废水处理工程中pH监控系统的设计思路和小试的工艺流程。     

舟山潮差带海相沉积物的物理和化学特征

为舟山潮差带海相沉积物固结机理的深入研究提供物质基础,采用激光粒度仪分析了海相沉积物的粒度组成,并测试了海相沉积物的化学元素、化合物种类及其相对含量,还使用X-射线衍射技术分析了海相沉物的矿物组成。结果表明:海相沉积物含水率高、初始孔隙比大、呈流塑状,为低液限粉质黏土;活性指数为12.4,属于活动黏性土,矿物的亲水性较好;全盐含量高达9~11.2 g/kg,阳离子交换能力不强,有机质含量(5.82~12.7 g/kg)较高;pH 值为7.35~8.36,呈弱碱性,加上孔隙水中K+ ,Na+ ,Ca2+ ,Mg2+ 的存在,使得高岭石常不稳定,有向伊利石、蒙脱石或绿泥石转化的趋势。     

天津冬季一次污染过程中NOx和O3的立体分布特征

由于大气是一个复杂介质,低层大气中湍流的存在使物质和能量的交换很剧烈,污染物的扩散传输现象明显.对不同高度不同区域的低层大气做立体观测,获取气态污染物浓度分布最直接的资料很有必要.综合利用地面观测站点、系留气球和飞机平台,于2016年11月25—26日在天津武清高村一次污染天气条件下对NO_x和O₃进行立体观测,得到了污染物的地面、垂直和低空区域分布特征,并结合气象因子进行分析研究.观测结果表明,地面$\varphi $（NO_x）水平较高,日均值为230×10-9,超过了GB 3095—2012《环境空气质量标准》二级标准的限值,反映了高村冬季较高的污染水平,主要受当地交通源排放的影响.$\varphi $（NO_x）随高度的上升呈下降趋势,受风速的影响明显,主要积聚在逆温层以下.低空$\varphi $（NO_x）市区高于郊区,而处于更远郊区的高村$\varphi $（NO_x）与市区相当,也反映了高村本地较高的NO_x污染.高村地面$\varphi $（O₃）低,日最大8 h平均值为8×10-9,反映了冬季低温辐射弱、光化学反应强度低的特点.随高度增加$\varphi $（O₃）呈上升趋势,垂直分布特征主要与温度层结有关.低空$\varphi $（O₃）呈郊区高于市区,高村（远郊区）高于近郊区的特征.研究显示,$\varphi $（NO_x）的升高导致$\varphi $（O₃）下降,这可能与高村冬季的$\varphi $（VOCs）/$\varphi $（NO_x）偏低有关,需要结合VOCs观测数据做进一步分析.