Landscape Controls on Mercury in Streamwater at Acadia National Park, USA

Fall and spring streamwater samples were analyzed for total mercury (Hg) and major ions from 47 locations on Mount Desert Island in Maine. Samples were collected in zones that were burned in a major wildfire in 1947 and in zones that were not burned. We hypothesized that Hg concentrations in streamwater would be higher from unburned sites than burned watersheds, because fire would volatilize stored Hg. The Hg concentrations, based on burn history, were not statistically distinct. However, significant statistical associations were noted between Hg and the amount of wetlands in the drainage systems and with streamwater dissolved organic carbon (DOC). An unexpected result was that wetlands mobilized more Hg by generating more DOC in total, but upland DOC was more efficient at transporting Hg because it transports more Hg per unit DOC. Mercury concentrations were higher in samples collected at lower elevations. Mercury was positively correlated with relative discharge, although this effect was not distinguished from the DOC association. In this research, sample site elevation and the presence of upstream wetlands and their associated DOC affected Hg concentrations more strongly than burn history.     

Mercury Contamination of Biota from Acadia National Park, Maine: A Review

We reviewed literature reporting both total and methylmercury from biota from Acadia National Park, Maine, USA. Our review of existing data indicates that 1) mercury contamination is widespread throughout the Park’s various aquatic ecosystems; 2) mercury pollution likely represents a moderate to high risk to biota inhabiting the Park; and 3) biota at all trophic levels possess elevated concentrations of both total and methylmercury. Watershed fire history and the resulting post-fire forest succession patterns are an important landscape attribute governing mercury cycling at Acadia National Park. Therefore, park service personnel should consider these factors when planning and implementing Hg biomonitoring efforts. Additional baseline funding from the National Park Service for Hg research and biomonitoring will likely be required in order to further evaluate the spatial and temporal patterns of mercury contamination in the park’s biota. An erratum to this article can be found at     

Controls on Mercury and Methylmercury Deposition for Two Watersheds in Acadia National Park, Maine

Throughfall and bulk precipitation samples were collected for two watersheds at Acadia National Park, Maine, from 3 May to 16 November 2000, to determine which landscape factors affected mercury (Hg) deposition. One of these watersheds, Cadillac Brook, burned in 1947, providing a natural experimental design to study the effects of forest type on deposition to forested watersheds. Sites that face southwest received the highest Hg deposition, which may be due to the interception of cross-continental movement of contaminated air masses. Sites covered with softwood vegetation also received higher Hg deposition than other vegetation types because of the higher scavenging efficiency of the canopy structure. Methyl mercury (MeHg) deposition was not affected by these factors. Hg deposition, as bulk precipitation and throughfall was lower in Cadillac Brook watershed (burned) than in Hadlock Brook watershed (unburned) because of vegetation type and watershed aspect. Hg and MeHg inputs were weighted by season and vegetation type because these two factors had the most influence on deposition. Hg volatilization was not determined. The total Hg deposition via throughfall and bulk precipitation was 9.4 μg/m²/year in Cadillac Brook watershed and 10.2 μg/m²/year in Hadlock Brook watershed. The total MeHg deposition via throughfall and bulk precipitation was 0.05 μg/m²/year in Cadillac Brook watershed and 0.10 μg/m²/year in Hadlock Brook watershed.     

制定ISO14000系列标准国家方案的几个重要问题

ＩＳＯ１４０００系列标准以生命周期评价理论和方法标准为基础,推出了环境管理体系与环境标志等国际环境管理标准,反映出现代环境意识引导下的双绿色发展模式,并成为可持续发展道路的重要组成部分。     

2019年国庆节前后北京气态氨和气溶胶铵盐浓度的同步观测

我国自2013年实施《大气污染防治行动计划》以来,大气细颗粒物(PM2.5)特别是硫酸盐浓度迅速下降,但硝酸盐浓度降幅较小,大气中过量的氨气(NH3)是维持硝酸盐居高不下的主要因素.迄今,我国生态环境部门尚未将NH3纳入常规观测,以往有关NH3和气溶胶铵盐(NH4+)的研究多是分别进行的,缺少同步观测.由于NH3和NH...     

TROPHIC STATE EVALUATION FOR SELECTED LAKES IN GRAND TETON NATIONAL PARK1

ABSTRACT: Increased visitation at Grand Teton National Park (GTNP) has raised concerns about impacts on surface water in the park. The purposes of this study are to perform a benchmark trophic state survey for comparison to future evaluations and to identify possible areas of concern. Four watershed regions based on geographic and geologic features were delineated for study. Six Alpine lakes, six Moraine lakes, three Valley lakes, and two Colter Bay lakes are evaluated. Lakes were sampled for total phosphorus (TP), chlorophyll‐a, and transparency. The water quality, as defined by trophic state, in the park is generally good. Oligotrophic to mesotrophic conditions were found in the Alpine and Moraine lakes and mesotrophic to eutrophic conditions were found in the Colter Bay and Valley lakes. High inflow TP concentrations in the park's northeast side may be due to the presence of natural geologic phosphate from the Phosphoria Formation.     

国家环境信息系统的开发

本文概述了信息技术的发展状况和国家“七五”科技攻关“国家环境信息数据库研究”课题的背景、方法及该课题的研究成果,“国家环境信息系统”的总体结构、规模、子系统简介以及该系统“八五”继续开发的目标.     

Diffusive wave models for operational forecasting of channel routing at continental scale

Operational forecast models require robust, computationally efficient, and reliable algorithms. We desire accurate forecasts within the limits of the uncertainties in channel geometry and roughness because the output from these algorithms leads to flood warnings and a variety of water management decisions. The current operational Water Model uses the Muskingum-Cunge method, which does not account for key hydraulic conditions such as flow hysteresis and backwater effects, limiting its ability in situations with pronounced backwater effects. This situation most commonly occurs in low-gradient rivers, near confluences and channel constrictions, coastal regions where the combined actions of tides, storm surges, and wind can cause adverse flow. These situations necessitate a more rigorous flow routing approach such as dynamic or diffusive wave approximation to simulate flow hydraulics accurately. Avoiding the dynamic wave routing due to its extreme computational cost, this work presents two diffusive wave approaches to simulate flow routing in a complex river network. This study reports a comparison of two different diffusive wave models that both use a finite difference solution solved using an implicit Crank–Nicolson (CN) scheme with second-order accuracy in both time and space. The first model applies the CN scheme over three spatial nodes and is referred to as Crank–Nicolson over Space (CNS). The second model uses the CN scheme over three temporal nodes and is referred to as Crank–Nicolson over Time (CNT). Both models can properly account for complex cross-section geometry and variable computational points spacing along the channel length. The models were tested in different watersheds representing a mixture of steep and flat topographies. Comparing model outputs against observations of discharges and water levels indicated that the models accurately predict the peak discharge, peak water level, and flooding duration. Both models are accurate and computationally stable over a broad range of hydraulic regimes. The CNS model is dependent on the Courant criteria, making it less computational efficient where short channel segments are present. The CNT model does not suffer from that constraint and is, thus, highly computationally efficient and could be more useful for operational forecast models.     

上海化学工业区地下水环境质量评价

以上海化学工业区地下水水质监测资料为基础,结合实际情况选取22项评价因子,依据地下水质量标准,采用综合评价法对该地区的地下水环境质量进行评价分析.评价结果表明,化工区地下水环境质量状况较差,监测项目中无机物超标情况严重,某些金属离子和酸根离子含量较高; 而有机物指标含量均低于方法检出限.此外,该地区地下水水化学特征呈明显的水平分带性,由南至北宏量元素逐渐降低,酚类含量逐渐增高,而重金属含量则基本保持不变,水化学类型由咸水类型向淡水类型转变.     

The Antiquities Act,national monuments,and the regional economy

Large, landscape-scale national monuments have long been controversial. It has been claimed that large monuments harm local economies by restricting growth of the grazing, timber, mining, and energy industries. Others have asserted that large monuments aid economic growth by reducing reliance on volatile commodity markets and fostering tourism growth. In this study, we use a synthetic control approach to measure the average causal effect of nine national monument designations on county-level per capita income. We find no evidence that monument designation affected per capita income in any of 20 counties hosting nine large (>50,000 acres) national monuments established under the Antiquities Act (six monuments) or by legislative action (three monuments). The broad economic claims of both advocates and critics of large national monuments have little empirical support. The absence of a designation effect for large national monuments is likely due to the attributes of federal land and the legal constraints under which it is managed.