Pond bank access as an approach for managing toxic cyanobacteria in beef cattle pasture drinking water ponds

Forty-one livestock drinking water ponds in Alabama beef cattle pastures during were surveyed during the late summer to generally understand water quality patterns in these important water resources. Since livestock drinking water ponds are prone to excess nutrients that typically lead to eutrophication, which can promote blooms of toxigenic phytoplankton such as cyanobacteria, we also assessed the threat of exposure to the hepatotoxin, microcystin. Eighty percent of the ponds studied contained measurable microcystin, while three of these ponds had concentrations above human drinking water thresholds set by the US Environmental Protection Agency (i.e., 0.3 μg/L). Water quality patterns in the livestock drinking water ponds contrasted sharply with patterns typically observed for temperate freshwater lakes and reservoirs. Namely, we found several non-linear relationships between phytoplankton abundance (measured as chlorophyll) and nutrients or total suspended solids. Livestock had direct access to all the study ponds. Consequently, the proportion of inorganic suspended solids (e.g., sediment) increased with higher concentrations of total suspended solids, which underlies these patterns. Unimodal relationships were also observed between microcystin and phytoplankton abundance or nutrients. Euglenoids were abundant in the four ponds with chlorophyll concentrations >?250 μg/L (and dominated three of these ponds), which could explain why ponds with high chlorophyll concentrations would have low microcystin concentrations. Based on observations made during sampling events and available water quality data, livestock-mediated bioturbation is causing elevated total suspended solids that lead to reduced phytoplankton abundance and microcystin despite high concentrations of nutrients, such as phosphorus and nitrogen. Thus, livestock could be used to manage algal blooms, including toxic secondary metabolites, in their drinking water ponds by allowing them to walk in the ponds to increase turbidity.     

Identifying key areas of ecosystem services potential to improve ecological management in Chongqing City,southwest China

Because natural ecosystems and ecosystem services (ES) are both critical to the well-being of humankind, it is important to understand their relationships and congruence for conservation planning. Spatial conservation planning is required to set focused preservation priorities and to assess future ecological implications. This study uses the combined measures of ES models and ES potential to estimate and analyze all four groups of ecosystem services to generate opportunities to maximize ecosystem services. Subsequently, we identify the key areas of conservation priorities as future forestation and conservation hotspot zones to improve the ecological management in Chongqing City, located in the upper reaches of the Three Gorges Reservoir Area, China. Results show that ecosystem services potential is extremely obvious. Compared to ecosystem services from 2000, we determined that soil conservation could be increased by 59.11%, carbon sequestration by 129.51%, water flow regulation by 83.42%, and water purification by 84.42%. According to our prioritization results, approximately 48% of area converted to forests exhibited high improvements in all ecosystem services (categorized as hotspot-1, hotspot-2, and hotspot-3). The hotspots identified in this study can be used as an excellent surrogate for evaluation ecological engineering benefits and can be effectively applied in improving ecological management planning.     

Soil surface Hg emission flux in coalfield in Wuda,Inner Mongolia,China

Hg emission flux from various land covers, such as forests, wetlands, and urban areas, have been investigated. China has the largest area of coalfield in the world, but data of Hg flux of coalfields, especially, those with coal fires, are seriously limited. In this study, Hg fluxes of a coalfield were measured using the dynamic flux chamber (DFC) method, coupled with a Lumex multifunctional Hg analyzer RA-915+ (Lumex Ltd., Russia). The results show that the Hg flux in Wuda coalfield ranged from 4 to 318 ng m^?2 h^?1, and the average value for different areas varied, e.g., coal-fire area 99 and 177 ng m^?2 h^?1; no coal-fire area 19 and 32 ng m^?2 h^?1; and backfilling area 53 ng m^?2 h^?1. Hg continued to be emitted from an underground coal seam, even if there were no phenomena, such as vents, cracks, and smog, of coal fire on the soil surface. This phenomenon occurred in all area types, i.e., coal-fire area, no coal-fire area, and backfilling area, which is universal in Wuda coalfield. Considering that many coalfields in northern China are similar to Wuda coalfield, they may be large sources of atmospheric Hg. The correlations of Hg emission flux with influence factors, such as sunlight intensity, soil surface temperature, and atmospheric Hg content, were also investigated for Wuda coalfield.

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液液萃取-气相色谱法测定水质可萃取性石油烃C10~C40

建立了以环己烷为萃取剂、气相色谱法(氢火焰离子化检测器,FID)测定水质样品中可萃取性石油烃(C_(10)～C_(40))的分析方法。以正构烷烃混合标准溶液为定性和定量校准标准,以色谱峰面积总和与混合标准溶液总浓度建立校准曲线进行外标法定量。方法检出限为0.01 mg/L,经验证方法精密度和准确度良好。同时,分别以气相色谱法和红外光度法测定了地表水、污水处理厂出水、海水和化工废水等实际样品,对比实验结果表明,在可萃取性石油烃C_(10)～C_(40)的碳数范围内,气相色谱法的测试结果与红外光度法无明显差异,有较好的可比性。     

城镇化过程中的流域面源污染时空变化

以斧头湖流域为研究对象,在野外调查的基础上,借助遥感和GIS技术,对2008年、2015年斧头湖流域土地利用格局、人畜排放进行分析,利用输出系数模型解析斧头湖的面源污染负荷时空分布及主要来源。结果表明:斧头湖流域2008～2015年面源总氮（TN）和总磷（TP）负荷输出分别从由原来的 2 915 和 178 t 增长至 3 252 和 202 t。城镇化发展使得农村耕地面积减少,耕地对TN的输出贡献比例降低,但是耕地化肥使用依然是TN最主要来源。城镇化使得居民区对面源贡献增大,特别是TP的贡献显著增加。随着人们生活水平的提高,畜禽养殖对面源污染的贡献也显著增加,应予以足够重视     

基于DMSP-OLS夜间灯光数据的长江经济带城镇体系空间格局演变（1992～2013）

研究长江经济带城镇体系空间格局演变,对于透视长江经济带城镇体系空间格局演变特征和规律以及促进长江经济带城镇体系空间格局优化发展有着重要意义。利用多时相同期Landsat卫星数据以及运用聚类分析方法对长江经济带夜间灯光数据进行校正,并采用其他辅助数据法对比分析获取城镇建成区面积的阈值,在此阈值基础之上选取景观总面积、总斑块数量和聚集度指数等总共8个典型景观格局指标, 继而使用FRAG-STATS 4.2 软件对1992~2013年间长江经济带城镇发展的空间格局变化进行计算分析。研究结果表明：(1）1992~2013年间,长江经济带城镇化快速扩展,城镇建成区面积增加了9.68倍,斑块数量增加了2.39倍,斑块密度也得到较大的增加,反映出长江经济带城镇数量不断增加和城镇建成区面积不断扩大;（2）景观斑块形状复杂度逐渐上升,中小城市不断壮大,同时出现了较多的新兴小城镇,总边界长度和平均边界密度的年均增长速度分别为21.56%和21.58%,体现了长江经济带城镇间聚集度越来越高,相互影响也越来越大;(3）最大斑块指数和聚集度指数两个指标在整体上呈现出逐年下降的态势,但是景观总面积、总斑块数量和斑块密度等8个指标在演变过程中均存在一定的波动和无序化,反映出长江经济带在城镇化过程中呈现出不规则和无序化的特征。     

Larval and Juvenile Fish Assemblage Structure of Inshore Habitats in the Middle Reaches of Li River,China: Spatial and Temporal Patterns in Relation to Abiotic Factors

To evaluate the effect of abiotic factors on larval and juvenile fish assemblage in shallow waters of middle reaches of Li River, Guilin, China. Samplings were taken monthly at 7 stations in the mainstream and 2 stations in 3 tributaries from May 2014 to April 2015. Synchronously, temperature, pH, turbidity, conductivity, dissolved oxygen rainfall and discharge were obtained. In all, 11.886 larval and juvenile fish from 18 species belonging to 8 families, 16 genera was captured. Principal Component Analysis (PCA) showed obvious significant difference between the environmental variables across sampling areas and months. The results of Canonical Correspondence Analysis (CCA) indicated that water temperature, turbidity, discharge and rainfall were dominant factors on larval and juvenile fish assemblage.     

钙钛矿型催化剂催化湿式氧化处理煤气化废水纳滤浓缩液

采用溶胶-凝胶法制备了Mn掺杂钙钛矿型催化剂LaFexMn1-xO3,并以其为催化剂催化湿式双氧水氧化处理煤气化废水纳滤浓缩液。采用XRD,SEM,FTIR技术对催化剂进行了表征。表征结果显示：制备的催化剂均具有标准的钙钛矿型结构,其中,LaFe0.9Mn0.1O3的结构稳定,比表面积大。实验结果表明：制备的催化剂中LaFe0.9Mn0.1O3的催化活性最高,且稳定性好,连续使用5次后催化活性未见明显减弱;在H2O2投加量3.0 g/L、n（H2O2）∶n（LaFe0.9Mn0.1O3）=12∶1、反应温度160 ℃、反应压力1 MPa、浓缩液pH 3、反应时间60 min的最优条件下,COD、UV254和TOC的去除率分别达到80.9%、95.2%和68.0%,BOD5/COD由0.02提升至0.40,可生化性大幅提高。     

臭氧氧化—湿式钙法吸收工艺对烟气的同时脱硫脱硝

采用臭氧氧化—湿式钙法吸收工艺对模拟烟气进行同时脱硫脱硝处理。O₃于150 ℃下具有较高的热稳定性,可将NO氧化为高价态氮氧化物,且NO氧化率随n（O₃）∶n（NO）的增大而逐渐提高。烟气中SO₂和H₂O的存在对NO氧化率的影响不大。O₃对SO₂的氧化率较低,约为5%。3%（w）石灰石浆液对SO₂的吸收率接近100%,NO_x吸收率随n（O₃）∶n（NO）的增大而逐渐提高,当n（O₃）∶n（NO）为1.6时NO_x吸收率可达约65%。SO₂能促进吸收液对NO_x的脱除。石灰石浆液中加入0.2%（w）的（NH₄）₂SO₃或Na₂SO₃后NO_x吸收率可达约85%或82%,且吸收率随添加剂加入量的增加而提高,添加（NH₄）₂SO₃的NO_x吸收率略高于添加Na₂SO₃。     

过一硫酸盐的活化及其降解水中有机污染物机理的研究进展

基于活化过一硫酸盐（PMS）产生SO₄^-·的新型高级氧化技术,在芬顿和类芬顿催化降解水中有机污染物的研究中占有重要地位。本文从活化PMS方法的特点和用途出发,对目前活化PMS的主要方法进行了论述,并对活化PMS降解水中有机污染物的机理进行了探讨,最后对该领域研究中存在的问题进行了分析。指出,开发高效的协同活化PMS的方法将成为该领域研究的必然趋势。