Historical mercury contamination in sediments and catchment soils of Diss Mere, UK

A 5.3 m sediment core and soil samples were taken from Diss Mere and its catchment. The sediment core was dated and Hg analysed on the sediment and soil samples. The Hg record of the sediment core shows that Diss Mere has been contaminated for the past thousand years and the historical trends in sediment contamination are in good agreement with the development of the weaving industry in Diss and hemp cultivation in the region. Mercury contamination in Diss Mere has been significant and reached a peak in the mid-19th century with sediment Hg concentrations over 50 μg g⁻¹. Elevated Hg concentrations were also found in contemporary soils in residential areas with former industrial land use. Although local hemp cultivation and the traditional weaving industry were abandoned a hundred years ago, Hg contamination caused by these activities still exists in the catchment, and affects the lake.     

太湖流域土地利用变化特征与机制分析

太湖流域土地总面积36 895 km²，包括了上海、江苏、浙江两省一市的部分区域，其中，江苏占53%，浙江占33%，上海占14%。太湖流域土地利用按下垫面可以分为耕地、建设用地、水域和其他用地4种类型。采用2005年土地详查数据与上次防洪规划数据进行比较。研究发现：耕地是太湖流域最重要的下垫面，占土地总面积的36.6%，建设用地占土地占面积的23%，与耕地的矛盾十分尖锐，水域面积较大，占土地总面积的14.5%。1996~2005年，土地利用变化的总体趋势是，耕地面积减少，减少幅度最大的地区在太湖流域江苏部分，两省一市建设用地均有30%左右的增长幅度，土地围垦得到有效控制，水域面积略有下降。人口增长和城市化快速发展、经济发展、效益驱动与土地管制差异是造成土地利用变化的主要原因     

湖泊重要入湖河流稳定水像元提取技术

利用2010年ALOS影像研究了归一化水体指数(NDWI)在两种极端情况下,即像元四边与河岸线最小夹角分别为0°和45°,与离岸距离之间的关系,提出了获得稳定水像元的最小河宽,并以太湖6条重要入湖河流(西苕溪、望虞河、太浦河、乌溪港、梁溪-东清河、武进港)为例,研究了稳定水像元的分布。结果表明,NDWI与离岸距离之间的关系可用Logistic方程进行拟合,两种极端情况的p值均小于0.01;最小夹角为0°和45°的情况下,获得稳定水像元的最小河宽分别为96 m和88 m,即当河宽大于96 m时,可在ALOS影像上获得稳定的水像元;6条入湖河流可获得稳定水像元的长度占总长的4.59%~100%,难以获取稳定水像元的最长距离为0~18.55 km。     

Sexual difference in mercury concentrations of lake trout (Salvelinus namaycush) from Lake Ontario

We determined total mercury (Hg) concentrations in 50 female lake trout (Salvelinus namaycush) and 69 male lake trout from Lake Ontario (Ontario, Canada and New York, United States). Results showed that, on average, males were 8% higher in Hg concentration than females in Lake Ontario. We also used bioenergetics modeling to determine whether a sexual difference in gross growth efficiency (GGE) could explain the observed sexual difference in Hg concentrations. According to the bioenergetics modeling results, male GGE was about 3% higher than female GGE, on average. Although the bioenergetics modeling could not explain the higher Hg concentrations exhibited by the males, a sexual difference in GGE remained a plausible explanation for the sexual difference in Hg concentrations of the lake trout. In an earlier study, male lake trout from Lake Ontario were found to be 22% higher in polychlorinated biphenyl (PCB) concentration than females from Lake Ontario. Thus, although males were higher in both Hg and PCB concentrations, the degree of the sexual difference in concentration varied between the two contaminants. Further research on sexual differences in Hg excretion rates and Hg direct uptake rates may be needed to resolve the disparity in results between the two contaminants.     

政府主导型流域生态补偿机制研究——对子牙河流域生态补偿机制的思考

作为消除生态环境资源开发利用过程中负外部性的重要手段,研究生态补偿机制对于指导我国流域生态环境资源开发和流域环境污染治理具有重要的现实意义.本文选取流域生态补偿机制作为研究对象,从生态补偿思想的来源、内涵、实施模式、补偿标准等角度系统梳理了相关领域的研究成果,并论述了市场主导的流域生态补偿机制和政府主导的流域生态补偿机制两种模式的区别与联系.在此基础上,文意从基本思路、政策框架、监管体系等维度分析评述了子牙河流域生态补偿机制,发现子牙河流域生态补偿机制是将生态补偿基金扣缴制度、改良的政绩考核制度、生态补偿基金使用监督管理制度等组成有机整体的运行体系,属于典型的政府主导模式,并剖析了子牙河流域生态补偿机制取得成效的原因.最后,本文认为,基于现阶段国情,我国应推行由政府主导的流域生态补偿机制,并就完善政府主导的流域生态补偿机制提出了相关政策建议.     

Vertical and horizontal distribution,source identification,ecological and toxic risk assessment of heavy metals in sediments of Lake Aygır,Kars, Turkey

Surface and core sediment samples were collected from Lake Ayg?r, Turkey, to determine heavy metal distribution, probable sources and potential ecological and toxic risks for the lake. Heavy metals, total sulfur, total phosphate, total organic carbon, chlorophyll degradation products, and CaCO₃ content were established. The enrichment factor, PLI, potential ecological risk index, and toxic risk index were calculated. Zn was determined to have the highest accumulation in surface sediment, followed by Cr, Pb, and Cd, respectively. Cd was the only element that exceeded the critical value of 40 and posed a moderate potential ecological risk. According to TRI, no ecotoxic risk was found. It is thought that local fossil fuel consumption is responsible for the accumulation of heavy metals since there is a lack of urbanization, industrialization, and agricultural activities around the lake.     

鄱阳湖典型洲滩湿地土壤质地与水分特征参数研究

频繁干湿交替增强了鄱阳湖洲滩土壤水对湿地系统的动态调节作用。以鄱阳湖吴城国家自然保护区的一个典型洲滩湿地为研究区,调查分析了土壤质地沿高程梯度的分布特征,确定了不同土壤质地的水分特征参数,并阐述了土壤质地与其水分特征参数的空间异质性。结果发现:该洲滩湿地主要分布砂土、粉壤土和粘土三种类型。水平断面方向上,粒径较粗的砂土和粉壤土主要分布在高位滩地,而粒径相对较细的粘土主要分布在近湖区开阔水面的低位滩地;土壤剖面方向上,土壤质地呈现出固有分层特性。van Genuchten模型应用于鄱阳湖洲滩湿地土壤水分特征曲线拟合,证实了该模型在鄱阳湖洲滩湿地的适用性。模型结果表明土壤残余含水率θr变化约9%~19%,饱和含水率θs变化约42%~57%,土壤进气值的倒数α约0.01 cm~(–1),水分特征曲线形状参数n介于1.11~4.65之间。土壤含水率变化对van Genuchten模型中参数α和n较为敏感,而对θr和θs的敏感性相对较弱。研究成果可为后续该区域以及全湖区湿地生态水文模型的构建和发展提供背景信息和参数资料。     

2000~2013年鄱阳湖流域蒸散量时空变化

蒸散是陆地表面水分循环的重要过程，是研究流域水资源、水循环等领域的重要参数。以鄱阳湖流域为研究对象，利用鄱阳湖流域5个主要子流域水文控制站监测流量资料和气象站监测降水资料，根据水量平衡原理计算各子流域年度蒸散，验证MODIS蒸散数据产品（ET_MOD），并分析2000~2013年鄱阳湖流域蒸散时空变化状况和土地利用变化对蒸散量的影响。研究结果表明：（1）ET_MOD具有较高的精度，年蒸散量的平均误差为165.9 mm，平均相对误差为9.78%；（2）2000~2013年鄱阳湖流域的年蒸散变化范围875.4~912.2 mm；鄱阳湖流域总蒸散量呈先增加后减少的“几”字形季节变化特征；（3）从蒸散量与地形特征的关系看，鄱阳湖平原区蒸散量低，周边的山地丘陵区较高；各子流域的蒸散量表现为：赣江流域 > 抚河流域 > 信江流域 > 修水流域 > 饶河流域；（4）土地利用方式对蒸散量有显著的影响，各土地利用类型的平均蒸散量表现为：林地 > 农田 > 草地 > 未利用地。     

Tourism and wetland conservation: application of travel cost and willingness to pay an entry fee at Ghodaghodi Lake Complex,Nepal

This study investigated the need and applicability of wetland tourism for resource conservation, using the case of Ghodaghodi Lake Complex, a Ramsar Site in western Nepal. The travel cost method (TCM) was used to determine the recreation potential of the lake complex, while the contingent valuation method (CVM) was used to calculate willingness of visitors to pay an entry fee as a payment vehicle for conservation. The per capita travel cost was found to be NPR 540 (US $7.71), while the mean willingness to pay an entry fee was NPR 34 (US $0.48) per visitor per entry. In addition, factors affecting wetland visitation rates and maximum willingness to pay were identified. Policy implications include the establishment of an entry fee system to offset conservation budgetary constraints, government investment in social benefits equating to at least per capita travel cost identified, and public‐private partnerships, with community participation in tourism promotion and wetland conservation.     

鄱阳湖出流水质2004~2014年变化及其对水位变化的响应:对水质监测频率的启示

通过对鄱阳湖湖口2004~2014年以周为单位的水质指标，包括溶解氧（DO），氨氮（NH₄⁺-N）和高锰酸盐指数（COD_Mn）的变化特征及其与水位响应关系进行分析，并对合理的监测频率进行了探讨。结果表明：（1）就DO，NH₄⁺-N和COD_Mn而言，鄱阳湖出湖水质在2004~2014年没有显著恶化的趋势，然而在年内呈现明显的周期性变化，其浓度与湖泊水位波动有较显著的负相关性（p<0.01），相关系数分别达到-0.63，-0.67和-0.36；（2）考虑水质指标在湖相状态与河相状态存在显著的差异（p<0.01），概率密度分布曲线进一步表明，在鄱阳湖呈湖相时，湖口NH₄⁺-N浓度小于0.25 mg/L的概率为93%，而在河相时仅为32.8%。DO与COD_Mn浓度在河湖相的特征与NH₄⁺-N相似。因此，在湖相状态下，鄱阳湖出流水质良好的概率更大，而高水位下的稀释作用可能是影响湖泊年内变化的主要控制因素；（3）时间序列分析表明DO，NH₄⁺-N和COD_Mn存在明显的自相关性，1~2月一次的监测频率基本能够准确的描述NH₄⁺-N和DO的动态变化特征，而COD_Mn仍需要1~2周一次的监测，从而避免过多的损失动态信息。能够为将来更深入的研究湖泊水情与水质定量关系提供基础和思路，从而为湖泊水环境管理和调控提供对策和建议。