Changes in nitrogen budget and potential risk to the environment over 20 years (1990–2010) in the agroecosystems of the Haihe Basin,China

The nitrogen balance can serve as an indicator of the risk to the environment of nitrogen loss from agricultural land. To investigate the temporal and spatial changes in agricultural nitrogen application and its potential threat to the environment of the Haihe Basin in China, we used a database of county-level agricultural statistics to calculate agricultural nitrogen input, output, surplus intensity, and use efficiency. Chemical fertilizer nitrogen input increased by 51.7% from 1990 to 2000 and by 37.2% from 2000 to 2010, concomitant with increasing crop yields. Simultaneously, the nitrogen surplus intensity increased by 53.5% from 1990 to 2000 and by 16.5% from 2000 to 2010, presenting a continuously increased environmental risk. Nitrogen use efficiency decreased from 0.46 in 1990 to 0.42 in 2000 and remained constant at 0.42 in 2010, partly due to fertilizer composition and type improvement. This level indicates that more than half of nitrogen inputs are lost in agroecosystems. Our results suggest that although the improvement in fertilizer composition and types has partially offset the decrease in nitrogen use efficiency, the environmental risk has still increased gradually over the past 20 years, along with the increase in crop yields and nitrogen application. It is important to achieve a better nitrogen balance through more effective management to significantly reduce the environmental risk, decrease nitrogen surplus intensity, and increase nitrogen use efficiency without sacrificing crop yields.     

Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment

Mercury(Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations(PNECs) for Hg(Ⅱ) and methyl mercury(Me Hg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5 × 10-3μg/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms,and their potential ecological risk should be respectively evaluated on the basis of mercury species.     

Excretion of manure-borne estrogens and androgens and their potential risk estimation in the Yangtze River Basin

The Yangtze River is the longest river in China, and the river basin spans one fifth of the area of the whole country. Based on statistical data, the excretion of manure-borne steroid hormones, including steroid estrogens(SEs) and steroid androgens(SAs), in 10 provinces of China within the region has been estimated. The potential environmental and ecological risk of manure-borne steroid estrogens to the surface water in this region was also assessed. The manure-borne SE and SA excretions in the 10 provinces and municipalities vary in the order: Sichuan Hunan Hubei Yunnan Jiangsu Anhui Jiangxi Chongqing Qinghai Shanghai. The highest increase of manure-borne SEs(1434.3 kg)and SAs(408.5 kg) was found in Hunan and Hubei provinces, respectively, and the total excretion in 2013 was 65% more than 15 years earlier in these two provinces. However, the emissions in Anhui and Shanghai decreased in this 15 year period of time. Swine urine,chicken feces, cattle urine, and laying hen feces were considered the dominant sources of manure-borne E1, βE2, αE2, and SAs, respectively. Although Jiangsu province did not have the largest excretion of manure-borne SEs, it had the highest level of predicted17β-estradiol equivalency(EEQs) value of 16.65 ng/L in surface water because of the limited surface water resources. According to the lowest observable effect level of 10 ng/L for17β-estradiol, the manure-borne SEs in Jiangsu province might potentially pose ecological risk to its wild aquatic organisms.     

战场环境下装备保障信息系统安全风险与防护

目的研究战场环境下装备保障信息系统的安全问题。方法从装备保障及装备保障信息系统的概念、分类和复杂战场环境下装备保障信息系统所面临的安全威胁入手,依照五分法把装备保障信息系统安全风险划分为5个等级,推导出风险评估模型,提出实施装备保障信息系统安全防护的技战术策略。结果战场环境下,为确保整个作战进程中装备保障活动安全、有效、稳定地进行,装备保障信息系统防护必须遵循统一协调、综合利用的积极防护原则,采用有效的风险控制措施加以应对。结论通过积极探索和发展装备保障信息安全与防护理论,找准战场环境信息防护中存在的薄弱环节,制定了装备保障信息安全防护策略,加强装备保障信息系统的安全管理工作,最终提高我军装备保障信息系统的防护能力。     

贵阳市土壤地球化学背景与生态环境分析

通过1∶250 000多目标区域地球化学调查,获得了贵阳市及邻区表、深层土壤中54项化学指标的地球化学背景值、基准值等参数。研究区总体土壤环境呈中偏酸性,对生态环境影响较大。土壤化学物质组成丰富,地球化学背景分布不均匀。除活动性强的化学组分对成土母质有分异外,多数化学组分对成土母质继承性显著。表层土壤有机碳、全碳、硫、氮、硒、氟和汞、镉、砷等的地球化学背景值显著高于深层土壤和我国其它城市地球化学基准值。前者适宜发展生态富硒特色农业,后者表明土壤环境安全形势严峻。土壤地球化学背景为生态环境评价和其它相关学科研究提供了科学基础,由此提出生态环境保护和利用建议。     

对生态红线的研究——宁夏生态红线划定的问题和思考

为了贯彻国家的可持续发展战略,更有效地解决中国的环境危机以及更好地进行中国的生态文明建设,就必须建立底线思维.中央第十八届三中全会通过的《中共中央关于全面深化改革若干重大问题的决定》明确规定了要划定生态保护红线.通过对生态保护红线的相关文献和政策进行分析,提出生态红线的类型和划定的思考,结合生态红线落地问题,对宁夏生态红线划定中存在的问题进行思考,以期为全国生态红线划定和生态保护提供参考.     

基于耦合模型的城市化与水资源保护关系研究——以南京市为例

利用耦合度模型,建立城市化综合水平与水资源保护综合水平指标评价体系,对南京市2005年-2014年城市化与水资源保护耦合关系度量化分析.结果表明:南京城市化与水资源保护耦合度总体波动式增长,其中2005年-2012年处于中度耦合时期,2013年-2014年处于高度协调时期;南京城市化综合水平与水资源保护综合水平呈现稳量增长趋势,但后者滞后于前者.为促进南京城市化与水资源保护关系向高度耦合状态发展,应尽快优化产业层级,促进第三产业链的延伸;同时尽快建立水资源保护政府、企业和居民三方参与的协同保护机制.     

生态环境保护与农业可持续发展研究

针对生态环境保护与农业可持续发展问题,探讨了生态环境对农业可持续发展的影响,包括陕西省农业资源的现状、陕西省农业生态环境恶化、生态系统功能遭到破坏和由于生态环境恶化使自然灾害发生,探讨了保护生态环境与促进农业可持续发展,内容包括要积极保护生态环境促进农业可持续发展、要积极保护农业资源促进农业可持续发展、要积极发展现代农业科技促进农业可持续发展和要积极宣传生态环境保护促进农业可持续发展.     

基于情景信息扩散模型的雾霾社会风险演化仿真研究

雾霾灾害不仅危害公众健康,且风险信息的传播会引发社会次级风险。为了研究社会风险信息的扩散演化趋势,本文构建了雾霾社会风险的情景信息扩散模型。以中国2013年雾霾灾害为例,将风险信息扩散过程分为爆发期、扩散期和稳定期,分析了不同参数条件下的信息扩散规律。结果表明,政府应在风险信息爆发期和扩散期增大官方渠道信息的覆盖范围,尤其在爆发期需对自由渠道发布的信息进行严格监管,在社会风险扩大之前制定应对策略。     

环境保护工作新思路研究

中国环境保护工作的新形势和公益性属性为环境保护工作中实施社会治理提供了现实需求和理论基础.本文从社会治理的内涵入手,结合中国环境保护工作的形势和环境保护工作的公益属性分析,探讨了在环境保护工作中推进社会治理的可行性;从环境影响评价中公众参与存在的问题出发,分析了中国环境保护社会治理当前存在的问题;再此基础上,从社会治理制度、参与渠道等方面提出了以社会治理思路推进中国环境保护工作的思路.