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991.
992.
基于系统动力学(SD)模拟模型和Powell优化模型,建立了农村生活污水污染物削减量与治理费用的SD-Powell模拟优化耦合模型,该模型可模拟预测污染物排放量,建立污染物削减量与治理费用函数关系.在此基础上,以污水治理费用最小为目标,以污水处理量为约束条件,对区域污染物削减量进行空间优化,得到最小治理费用下的最大污染物削减量.以常州市为例进行实证分析,模拟结果显示,2020年常州市农村生活污水COD和NH3-N排放量将达到16583t和2551t,分别比2008年增长4.60%和4.59%.采用聚类方法将常州市51个乡镇划分为4类控制单元,得到4类地区COD、NH3-N治理费用函数.各单位治理资金削减量存在明显差异,COD削减率的排序依次为:I类控制单元413kg/万元、IV类控制单元 380kg/万元、II类控制单元352kg/万元、III类控制单元348kg/万元,NH3-N削减率的排序依次为:III类控制单元65kg/万元、I类控制单元64kg/万元、IV类控制单元58kg/万元、II类控制单元54kg/万元,全区域削减率达到100%需要的治理费用约为16870万元.污染物削减空间优化结果显示,基于控制单元空间优化的削减效率高于平均分配的结果,治理费用在1000 -16870万元/a范围,COD、NH3-N的削减率分别提高6.4%和7.4%,4类地区的优先排序顺序依次为I类,IV类,II类和III类. 相似文献
993.
Abstract: Fishing activities worldwide have dramatically affected marine fish stocks and ecosystems. Marine protected areas (MPAs) with no-take zones may enhance fisheries, but empirical evidence of this is scant. We conducted a 4-year survey of fish catches around and within an MPA that was previously fully closed to fishing and then partially reopened under regulated comanaged fishing. In collaboration with the fishers and the MPA authority, we set the fishing effort and selected the gear to limit fishing impact on key fish predators, juvenile fish stage, and benthic communities and habitats. Within an adaptive comanagement framework, fishers agreed to reduce fishing effort if symptoms of overfishing were detected. We analyzed the temporal trends of catch per unit of effort (CPUE) of the whole species assemblages and CPUE of the four most valuable and frequent species observed inside the opened buffer zone and outside the MPA investigated. After the comanaged opening, CPUE first declined and then stabilized at levels more than twice that of catches obtained outside the MPA. Our results suggest that working closely with fishers can result in greater fisheries catches. Partial protection of coastal areas together with adaptive comanagement involving fishers, scientists, and managers can effectively achieve conservation and fishery management goals and benefit fishing communities and alleviate overfishing. 相似文献
994.
工业城市不同功能区土壤和蔬菜中重金属污染及其健康风险评价 总被引:10,自引:0,他引:10
为了研究和评价工业城市不同功能区的土壤和蔬菜中重金属污染和健康风险状况,以株洲市为例,在工业区(石峰区)、农业区(芦淞区)和旅游区(大京风景区)分别采集土壤和蔬菜样品,分析重金属Cd、As、Pb、Hg、Zn、Cr和Cu的质量分数,并采用地质累积指数法(Igeo)和健康风险评价模型分别对土壤和蔬菜中重金属进行评价。结果表明:工业区、农业区和旅游区土壤中Cd、As、Pb、Hg、Zn、Cr和Cu的平均质量分数都超出湖南省土壤背景值,部分重金属甚至超出国家土壤环境质量二级标准。不同功能区土壤中重金属的地质累积指数(Igeo)表明:工业区、农业区和旅游区土壤受到不同程度的重金属污染,其中Cd和Hg的污染最为严重,污染程度依次是工业区〉农业区〉旅游区。不同功能区蔬菜中Cd、As、Pb和Zn的危害商(HQ)值都大于1.0,而Cu和Cr的危害商(HQ)都小于1.0。不同功能区蔬菜中重金属危害指数(HI)都大于10.0,尤其是工业区蔬菜的危害指数(HI)〉100.0,当地成年人食用受到重金属污染的蔬菜会导致严重的健康危害,其中Cd和As,是危害指数(HI)的主要贡献者,两者贡献率之和的范围为75%~89%,而Cr的贡献率几乎为0。 相似文献
995.
为了探讨不同森林恢复类型对土壤质量的影响,对南方紫色土区4种主要森林恢复类型及对照地土壤物理和化学特性进行了比较研究。结果表明:4种森林类型的土壤质量均高于长期干扰下对照的土地,天然次生林土壤质量又高于人工林,5种不同状况下土壤质量综合指数由大到小为:天然次生林(0.97)、石栎(Lithocarpus glaber)×木荷(Schima superba)阔叶混交林(0.77)、枫香(Liquidambar formsana)×木荷×石栎×香樟(Cinnamomum camphora)阔叶混交林(0.67)、杉木纯林(0.41)、对照(0.04)。导致人工林和对照地土壤质量相对较低的主要原因是:周期性的森林抚育使土壤结构较差、凋落物量较低和土壤养分流失严重。研究表明,在植被恢复初期阶段,自然恢复是最大限度发挥森林功能的有效途径。 相似文献
996.
重要生态功能区典型生态服务及其评估指标体系的构建 总被引:2,自引:0,他引:2
科学评估重要生态功能区的生态服务是管理者制定相关政策的基础,对促进重要生态功能区维护区域生态安全、支撑经济社会可持续发展具有重要意义。依据生态服务的空间转移特性,探索提出了重要生态功能区典型生态服务的概念与内涵,并在此基础上综合运用频度分析法、专家咨询法和层次分析法,构建了重要生态功能区水源涵养、土壤保持、防风固沙、生物多样性保护和洪水调蓄等典型生态服务的评估指标体系。结果表明:在指标体系中,影响水源涵养服务的主要是土壤质地和降水量;影响土壤保持服务的主要是植被覆盖度和丰富度指数;影响防风固沙服务的主要是植被覆盖度和大风时速;影响生物多样性服务的主要是植被景观多样性指数;影响洪水调蓄服务的主要是湿地容积和降水量。土壤、植被、地形和气候等生态因子是重要生态功能区典型生态服务产生与发挥的重要基础。 相似文献
997.
998.
以北京市某典型区域作为研究对象,在收集大量相关资料与实测历史噪声数据的基础上,对研究区域内的声环境质量影响因素进行灰色关联度分析,并运用灰色理论建立GM(1,1)模型进行预测。结果表明,影响城市区域声环境质量因素从大到小的排序依次为:机动车辆﹥常住人口数量﹥平均车流量﹥地区生产总值﹥城市道路桥梁﹥基础设施投资﹥治理噪声环保投资;以研究区域内噪声污染实测历史数据建立的GM(1,1)模型精度符合要求标准,根据GM(1,1)模型预测北京市“十二五”期间声环境质量达标且有轻微下降趋势。 相似文献
999.
Kathryn E. Murphy Mark C. Rains Michael G. Kittridge Mark T. Stewart Mark A. Ross 《Journal of the American Water Resources Association》2008,44(4):980-995
Abstract: The objective of this study was to use applied and naturally occurring geochemical tracers to study the hydrology of clay settling areas (CSAs) and the hydrological connectivity between CSAs and surrounding hydrological landscapes. The study site is located on the Fort Meade Mine in Polk County, Florida. The CSA has a well‐developed, subangular‐blocky, clay‐rich surface layer with abundant desiccation cracks and other macropores, and a massive, clay‐rich sublayer that is saturated below ~1.0‐2.5 m. A bromide tracer was applied to study hydrological processes in the upper part of the CSA. Bromide infiltrated rapidly and perched on a massive, clay‐rich sublayer. Bromide concentrations decreased in the upper part of the profile without being transported vertically down through the lower part of the profile suggesting that bromide was lost to lateral rather than to vertical transport. Infiltration and lateral flow were rapid suggesting that preferential flow through desiccation cracks and other macropores likely dominates flow in the upper part of the CSA. Naturally occurring solute and stable isotope tracers were used to study the hydrological connectivity between the CSA and the surrounding hydrological landscape. Three‐end mass‐balance mixing model results indicate that shallow and/or deep CSA water can be found in all downgradient waters and must be as much as ~50% of some downgradient waters. Discharge from the CSA to the surrounding surface water‐bodies and surficial aquifer occurs laterally through the berms and/or vertically through the massive, clay‐rich sublayer. However, the precise flow paths from the CSA to the surrounding hydrological landscape are unclear and the fluxes remain unquantified, so the precise effects of CSAs on the hydrology of the surrounding hydrological landscape also remain unquantified. 相似文献
1000.
Integrating Conservation and Development at the National Marine Park of Alonissos,Northern Sporades,Greece: Perception and Practice 总被引:1,自引:1,他引:0
Available information on the socioeconomic implications of marine protected areas (MPAs) for the socioculturally diverse Mediterranean
region is scant. The National Marine Park of Alonissos, Northern Sporades (NMPANS), Greece was established in 1992 as a foundation
for the conservation of the endangered Mediterranean monk seal Monachus monachus. The evolution of the degree of acceptance of and satisfaction from the NMPANS by involved stakeholder groups (fishermen,
tourism operators, hoteliers and owners of rooms to let, governmental bodies, nongovernmental bodies, students, domestic and
foreign tourists) were investigated 13 years after its establishment using written questionnaires delivered during personal
interviews. The initial positive attitude of local professionals for the NMPANS has eroded due to the unsatisfactory fulfillment
of expectations for socioeconomic development. Fishermen expressed dissatisfaction with, mistrust toward, and a reluctancy
to communicate with the NMPANS’s management body. They believe that the fishery areas have decreased in actual geographic
area because of the prohibitive measures; fish stocks are declining; compensation for damage to fishery equipment by the Mediterranean
monk seal and for the prohibitive measures should be provided; and stricter enforcement of regulations should take place.
On the other hand, tourism operators, who organize trips for tourists to the NMPANS, unanimously reported direct economic
benefits. Furthermore, there was a disparity in the perception of socioeconomic benefits derived from the NMPANS between governmental
bodies and local stakeholders. The governmental bodies and the nongovernmental organization MOm-Hellenic Society for the Study
and Protection of the Monk Seal postulated that there had been considerable socioeconomic benefits for the local community
of Alonissos due to the establishment of the NMPANS, whereas the local nongovernmental organization Ecological and Cultural
Movement of Alonissos claimed benefits were scant. Tourists (domestic and foreign) believe that the NMPANS is not the main
attraction to Alonissos Island but is part of a composite, including serenity, aesthetic beauty, and small-scale tourism development,
which can turn Alonissos Island into an ideal eco-tourism destination; a common aspiration for both the tourists and the local
community by general consensus. The aim of the NMPANS to integrate conservation and development lies in (1) the effectiveness
of the NMPANS management body in formulating a strategic management plan that would accommodate stakeholders’ interests and
aspirations and (2) a national policy of conservation and enhancement of natural resources with consistency and continuity.
Quantitative assessment of the socioeconomic effectiveness of the Mediterranean MPAs using a common methodology would facilitate
the identification of intraregional variation and better planning for the network of MPAs in the Mediterranean. 相似文献