武汉市实施清洁生产的方案构想

分析了武汉市工业特点。认为武汉市仍处于工业化加速发展时期,偏重型的工业结构和落后的总体技术水平造成武汉市工业污染严重,布局不合理则加剧了这一状况。为此,结合矿产资源缺管而水资源丰富的资源特点,提出了武汉市实施可持续发展、推行清洁生产的初步方案。（１）调整工业结构的大力发展轻工业,由偏重型结构向轻重工业协调发展转变;（２）对现有产品生产进行深加工,提高含量及其附加值;（３）积极发展高新技术,以此作为     

湖北农村降水中SO_4~(2-)浓度变化研究

在湖北农村 10个地点 ,利用澳大利亚集雨器自 1996年 1月至 1998年 6月 ,按季度采集大气降水样品测定SO2 - 4浓度 ,并对数据进行统计分析。研究结果表明 ,各地 1997年降水中SO2 - 4浓度年均值比 1996年显著升高 ;大多数地点 1996、1997、1998年 1季度和 2季度降水中SO2 - 4浓度呈逐年升高趋势 ;大多数地点每年 1、4季度降水中SO2 - 4浓度高 ,2、3季度降水中SO2 - 4浓度低 ,说明湖北农村降水中的硫对秋冬作物影响比对春夏作物影响大 ;湖北农村降水中SO2 - 4浓度近两年不仅有时间变化规律 ,而且同一季度内的地区差异也很明显 ,在 1996年和 1997年 8个季度 10个点的降水SO2 - 4浓度最大值中 ,有 4个最大值出现在襄樊 ,它是目前湖北继宜昌市区、恩施市区之后又一个酸雨发展较快的地区     

安徽省县域公路交通与经济发展空间格局及耦合研究

交通与经济系统相互影响又互为合作,二者的良性反馈与循环是区域协调均衡发展的切实保证。基于安徽省77个县(市)域研究单元,利用公路交通路网和社会经济数据,借助交通优势度模型、经济发展水平综合评价模型和耦合协调发展评价模型,考量分析了公路交通和经济发展的空间格局及其耦合协调特征。结果表明:(1)安徽省县域公路交通路网密度北高南低,总体较优;交通可达性呈"单核"圈层分异;区位优势度呈"多核"圈层分异;交通优势度正介于"多核"向"单核"圈层转变的过渡状态。(2)各县(市)经济发展水平整体呈"金字塔型"分化,低发展水平单元基数较大;优势单元多集中于皖江城市带地域;地级市市辖区经济发展水平普遍高于周边县(市)。(3)全省县域公路交通与经济发展耦合关系整体良好,但协调度水平总体偏低,绝大多数县(市)公路交通发展超前经济。如何依托既有公路交通支撑,加快推进县域经济发展,是打造全省公路交通与经济协调发展新格局的关键。     

中国三大粮食作物化肥施用特征及环境风险评价

基于中国三大粮食作物化肥施用强度及配方肥用量核算数据,运用化肥施用环境风险评价模型定量分析了2016年中国三大粮食作物化肥施用特征及其环境风险。结果表明:(1)2016年中国三大粮食作物普遍存在化肥施用过量现象,且不同区域之间单质肥料施用过量程度差异显著,其中,小麦和玉米种植单质肥料存在施用过量的空间范围及过量程度整体上要高于水稻。(2)中国三大粮食作物化肥施用环境风险具有显著的空间差异性,且处于相同风险等级的区域呈现出一定的空间邻近性。(3)中国三大粮食作物总化肥环境风险水平整体较低,但内蒙古、新疆和江苏的小麦种植以及内蒙古、甘肃和湖北等地的玉米种植化肥施用环境风险仍达到了中度或重度风险等级,应成为重点关注的区域。针对当前三大粮食作物化肥施用过量现象严重的问题,政府应当加快三大粮食作物配方肥的推广应用,出台政策措施鼓励企业按大配方生产配方肥,并引导企业在适宜地区进行销售,制定补贴政策以提高农民选用配方肥的积极性,开展科学指导和技术服务以提高农户科学施肥能力和认知水平。     

基于尾涡强度的无人机与民机纵向安全间隔评估研究

为了解决无人机频频入侵机场净空,与民航客机发生危险接近的问题,以碰撞风险为量化指标,对无人机与民机需要保持的纵向安全间隔进行评估研究。分析民机尾涡流场对无人机运行的影响,利用Crow近场涡强度消散理论,得到实际尾迹影响区改进Reich碰撞模板,据此建立CNS/GPS性能环境下的纵向间隔评估模型,通过Matlab进行间隔值求解。研究结果表明:模型可以较为准确地反映民机起飞初始爬升阶段无人机尾随运行时导航性能和尾涡迹对所需最小间隔值的影响,并得到给定安全目标水平的计算结果。     

太湖流域水环境保护目标责任考核机制研究

建立科学规范的环境保护目标责任考核机制是实现我国环境保护目标的重要手段之一。作为一个自上而下的制度典范,基层环境保护管理部门是环境管理目标的落实者也是被考核的对象。本研究以太湖流域水环境保护基层管理部门面临的水环境保护目标责任考核机制为研究对象,从水环境保护考核指标的设定、考核评价的实施以及考核结果的应用三个方面分析太湖流域水环境保护目标考核机制的实施现状。结果表明,现阶段的考核体系存在考核指标设置不合理、考核过程实施过程成本较高,以及考核结果缺乏对管理部门的激励性等问题。最后,本文从提高现阶段太湖流域水环境保护考核指标设定的科学性、协调不同部门之间的关系以及加强考核结果的公开与合理应用方面对太湖流域水环境保护目标责任考核机制提出了政策建议。     

Effect of alginate on the aggregation kinetics of copper oxide nanoparticles (CuO NPs): bridging interaction and hetero-aggregation induced by Ca<Superscript>2+</Superscript>

The stability of CuO nanoparticles (NPs) is expected to play a key role in the environmental risk assessment of nanotoxicity in aquatic systems. In this study, the effect of alginate (model polysaccharides) on the stability of CuO NPs in various environmentally relevant ionic strength conditions was investigated by using time-resolved dynamic light scattering. Significant aggregation of CuO NPs was observed in the presence of both monovalent and divalent cations. The critical coagulation concentrations (CCC) were 54.5 and 2.9 mM for NaNO₃ and Ca(NO₃)₂, respectively. The presence of alginate slowed nano-CuO aggregation rates over the entire NaNO₃ concentration range due to the combined electrostatic and steric effect. High concentrations of Ca²⁺ (>6 mM) resulted in stronger adsorption of alginate onto CuO NPs; however, enhanced aggregation of CuO NPs occurred simultaneously under the same conditions. Spectroscopic analysis revealed that the bridging interaction of alginate with Ca²⁺ might be an important mechanism for the enhanced aggregation. Furthermore, significant coagulation of the alginate molecules was observed in solutions of high Ca²⁺ concentrations, indicating a hetero-aggregation mechanism between the alginate-covered CuO NPs and the unabsorbed alginate. These results suggested a different aggregation mechanism of NPs might co-exist in aqueous systems enriched with natural organic matter, which should be taken into consideration in future studies.

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Graphical abstract Hetero-aggregation mechanism of CuO nanoparticles and alginate under high concentration of Ca²⁺

     

Drought-tolerant <Emphasis Type="Italic">Streptomyces pactum</Emphasis> Act12 assist phytoremediation of cadmium-contaminated soil by <Emphasis Type="Italic">Amaranthus hypochondriacus</Emphasis>: great potential application in arid/semi-arid areas

Microbe-assisted phytoremediation provides an effective approach to clean up heavy metal-contaminated soils. However, severe drought may affect the function of microbes in arid/semi-arid areas. Streptomyces pactum Act12 is a drought-tolerant soil actinomycete strain isolated from an extreme environment on the Qinghai-Tibet Plateau, China. In this study, pot experiments were conducted to assess the effect of Act12 on Cd tolerance, uptake, and accumulation in amaranth (Amaranthus hypochondriacus) under water deficit. Inoculated plants had higher Cd concentrations (root 8.7–33.9 %; shoot 53.2–102.1 %) and uptake (root 19.9–95.3 %; shoot 110.6–170.1 %) than non-inoculated controls in Cd-treated soil. The translocation factor of Cd from roots to shoots was increased by 14.2–75 % in inoculated plants, while the bioconcentration factor of Cd in roots and shoots was increased by 10.2–64.4 and 53.9–114.8 %, respectively. Moreover, inoculation with Act12 increased plant height, root length, and shoot biomass of amaranth in Cd-treated soil compared to non-inoculated controls. Physiochemical analysis revealed that Act12 enhanced Cd tolerance in the plants by increasing glutathione, elevating superoxide dismutase and catalase activities, as well as reducing malondialdehyde content in the leaves. The drought-tolerant actinomycete strain Act12 can enhance the phytoremediation efficiency of amaranth for Cd-contaminated soils under water deficit, exhibiting potential for application in arid and semi-arid areas.