典型城市臭氧污染源贡献及控制策略费效评估

东莞是珠三角O_3污染最严重的城市,使用RSM/CMAQ(曲面响应模型)法分析了珠三角区域人为排放的NO_x和VOCs对东莞市O_3浓度变化源贡献.2014基准年分析结果表明,扣除模型域外区域传输及天然源排放对O_3本底浓度贡献(41.00%)后,东莞本地VOCs排放对O_3贡献最大(18.50%),珠三角区域NO_x减排率13%时可持续降低东莞市O_3浓度.进一步使用ABa CAS-SE(空气污染控制成本效益与达标评估系统)对2017、2020、2025东莞市3个未来年O_3污染控制情景进行了费效评估.评估结果显示,NO_x和VOCs控制比例相对较低的2017年控制情景人体健康效益/区域控制成本比约为1.1;而控制比例相对较高的2025年东莞O_3达标情景效益成本比仅为0.1.这说明,在高减排率情景下,以末端治理为主的控制措施经济可行性较差,需综合采取产业/能源结构调整、清洁生产等措施实现NO_x和VOCs的大比例减排,实现东莞O_3的稳定达标.今后将进一步研究NO_x和VOCs减排对PM_(2.5)环境浓度及健康效益影响,开展多目标污染物协同控制费效评估.     

Chemical Stability of Capped Dredged Material Disposal Mounds in Long Island Sound, Usa

Geochemical analysis and visual inspection of cores collected from capped dredged material mounds revealed that in many cores, cap material was clearly distinguishable, both visually and chemically, from mound material. Contaminated dredged sediments were disposed in Long Island Sound eleven and seven years prior to sampling, and capped with uncontaminated dredged sediments. Core data provided no conclusive evidence of physical disturbance of, or chemical migration from, the contaminated mound sediments. Obvious chemical gradients of contaminant concentrations, which we propose are indicators of chemical migration, were not detected in the cores. Heterogeneity of the cap and mound sediments in some cores made the interface less distinct. We postulate that the preservation of spatial variability of sediment texture and associated contaminants observed within dredged material mounds is a result of the dredging process. Preservation of the textural and contaminant history of dredged sediments within finegrained cohesive cap materials provides evidence of the absence of physical or chemical disturbance.     

Trace-metal contamination in the glacierized Rio Santa watershed,Peru

The objective of this research is to characterize the variability of trace metals in the Rio Santa watershed based on synoptic sampling applied at a large scale. To that end, we propose a combination of methods based on the collection of water, suspended sediments, and riverbed sediments at different points of the watershed within a very limited period. Forty points within the Rio Santa watershed were sampled between June 21 and July 8, 2013. Forty water samples, 36 suspended sediments, and 34 riverbed sediments were analyzed for seven trace metals. The results, which were normalized using the USEPA guideline for water and sediments, show that the Rio Santa water exhibits Mn concentrations higher than the guideline at more than 50% of the sampling points. As is the second highest contaminating element in the water, with approximately 10% of the samples containing concentrations above the guideline. Sediments collected in the Rio Santa riverbed were heavily contaminated by at least four of the tested elements at nearly 85% of the sample points, with As presenting the highest normalized concentration, at more than ten times the guideline. As, Cd, Fe, Pb, and Zn present similar concentration trends in the sediment all along the Rio Santa.The findings indicate that care should be taken in using the Rio Santa water and sediments for purposes that could affect the health of humans or the ecosystem. The situation is worse in some tributaries in the southern part of the watershed that host both active and abandoned mines and ore-processing plants.     

One size fits all: stability of metabolic scaling under warming and ocean acidification in echinoderms

Responses by marine species to ocean acidification (OA) have recently been shown to be modulated by external factors including temperature, food supply and salinity. However the role of a fundamental biological parameter relevant to all organisms, that of body size, in governing responses to multiple stressors has been almost entirely overlooked. Recent consensus suggests allometric scaling of metabolism with body size differs between species, the commonly cited ‘universal’ mass scaling exponent (b) of ¾ representing an average of exponents that naturally vary. One model, the Metabolic-Level Boundaries hypothesis, provides a testable prediction: that b will decrease within species under increasing temperature. However, no previous studies have examined how metabolic scaling may be directly affected by OA. We acclimated a wide body-mass range of three common NE Atlantic echinoderms (the sea star Asterias rubens, the brittlestars Ophiothrix fragilis and Amphiura filiformis) to two levels of pCO₂ and three temperatures, and metabolic rates were determined using closed-chamber respirometry. The results show that contrary to some models these echinoderm species possess a notable degree of stability in metabolic scaling under different abiotic conditions; the mass scaling exponent (b) varied in value between species, but not within species under different conditions. Additionally, we found no effect of OA on metabolic rates in any species. These data suggest responses to abiotic stressors are not modulated by body size in these species, as reflected in the stability of the metabolic scaling relationship. Such equivalence in response across ontogenetic size ranges has important implications for the stability of ecological food webs.     

CONSERVATIONAL WATER PRICING FOR INCREASED WATER SUPPLY BENEFITS1

ABSTRACT: A study was undertaken to see if benefits from water supply could be increased by utilizing price-usage information in reservoir design studies. Three pricing policies were examined. The first policy assumed no price-use relationship, and quantity demanded was based on existing community usage with a low water rate. The price of water was set to recover system costs. A price-use relationship was assumed in the second policy and the water rate was constant. The price of water was determined from the associated system which provided maximum expected net benefits. The third policy assumed the price-use relationship and the price charged for water during each billing period was a non-linear function of storage which increased as the amount of water in storage at the beginning of the period decreased. It was found that the use of the conservation pricing policies substantially reduced storage requirements while providing demonstrable net benefits to the community and a large average supply. The conservation pricing policies substantially lowered the average price paid for water. The effect of uncertainty in consumer response to changes in price was studied by using a probabilistic price-use relationship. This uncertainty did not significantly reduce the effectiveness of the conservation policy. It was concluded that demand management by the use of a proper pricing policy could significantly increase net water supply benefits to a community.     

大气汞污染模拟研究进展及控制策略优化方法

简评了国内外大气汞污染模拟相关研究情况,指出目前我国大气汞排放模拟及污染控制研究工作非常缺乏,严重影响了我国汞污染控制策略制定以及"汞环境外交纠纷"的积极应对;并据此建议应该对我国大气汞污染模拟及控制策略优化进行系统研究,其研究内容包括:汞排放清单的建立、大气汞的长程输送、响应面模型软件(response surfac...     

Hypothesis Concerning the Causes of the Disappearance of Boreal Toads from the Mountains of Colorado

Recent reports of world-wide declines and extinctions of amphibian populations have raised questions about the relation of environmental change to the demise of certain amphibian species. Between 1974 and 1982, 11 populations of boreal toads ( Bufo boreas boreas ) in the West Elk Mountains of Colorado totally disappeared. The apparent cause of extinction of these toads was infection with the bacteria Aeromonas hydrophila . In this paper, the presence of disease in declining populations of these toads is used in conjunction with a variety of data from the literature to formulate a working hypothesis for explaining the cause of the decline of this species, and perhaps others:

     

Real-time PCR assay for detection and relative quantification of <Emphasis Type="Italic">Liocarcinus </Emphasis><Emphasis Type="Italic">depurator</Emphasis> larvae from plankton samples

Accurate species identification of decapod crustacean larvae is required to understand their population distributions, life cycle dynamics and interactions with their habitats. Analysis of plankton samples using morphological taxonomic methods and microscopy is time-consuming, requires highly skilled and trained operatives and may often be inaccurate. As complementary tools to classical identification methods, recent work has focused on the development of molecular approaches and shows their feasibility for species-specific identification. This study has developed real-time PCR assays utilising species-specific Taqman^® probes designed in the cytochrome oxidase I (COI) gene of Liocarcinus depurator, Necora puber, Carcinus maenas and Cancer pagurus. Our study then employed the probe and primers designed for L. depurator to obtain accurate identification and relative abundance estimates of L. depurator larvae in plankton samples collected between March 2005 and October 2006. Ranges of larval abundances were derived from a standard curve created from plankton samples spiked with a known number of larvae reared in the laboratory. Inhibition of the PCR reaction was shown to be an important factor and our results suggested that 0.1 ng of DNA as template provided accurate identification and avoided inhibition. Real-time PCR was shown to provide accurate species identification on unsorted plankton samples and could be suitable for the estimation of larval abundances in the plankton, although more work must be done to improve the accuracy of those estimations.     

Impact of curve construction and community dynamics on the species-time relationship

The species-time relationship (STR) describes how the species richness of a community increases with the time span over which the community is observed. This temporal scaling provides insight into theoretical questions on species diversity patterns as well as applied questions on the appropriate time scale for biodiversity assessments. To better understand STRs, we discuss the methods used to construct STRs in the literature and derive the impact of curve construction on STR properties. Using vegetation data from Mount St. Helens, Washington, USA, we illustrate the sensitivity of the STR to construction under colonization-dominated dynamics. This study highlights the importance of considering the type of STR when interpreting, comparing, and applying STRs, particularly in disturbed or successional systems.     

Effects of different management strategies on long-term trends of Australian threatened and near-threatened mammals

Monitoring is critical to assess management effectiveness, but broadscale systematic assessments of monitoring to evaluate and improve recovery efforts are lacking. We compiled 1808 time series from 71 threatened and near-threatened terrestrial and volant mammal species and subspecies in Australia (48% of all threatened mammal taxa) to compare relative trends of populations subject to different management strategies. We adapted the Living Planet Index to develop the Threatened Species Index for Australian Mammals and track aggregate trends for all sampled threatened mammal populations and for small (<35 g), medium (35–5500 g), and large mammals (>5500 g) from 2000 to 2017. Unmanaged populations (42 taxa) declined by 63% on average; unmanaged small mammals exhibited the greatest declines (96%). Populations of 17 taxa in havens (islands and fenced areas that excluded or eliminated introduced red foxes [Vulpes vulpes] and domestic cats [Felis catus]) increased by 680%. Outside havens, populations undergoing sustained predator baiting initially declined by 75% but subsequently increased to 47% of their abundance in 2000. At sites where predators were not excluded or baited but other actions (e.g., fire management, introduced herbivore control) occurred, populations of small and medium mammals declined faster, but large mammals declined more slowly, than unmanaged populations. Only 13% of taxa had data for both unmanaged and managed populations; index comparisons for this subset showed that taxa with populations increasing inside havens declined outside havens but taxa with populations subject to predator baiting outside havens declined more slowly than populations with no management and then increased, whereas unmanaged populations continued to decline. More comprehensive and improved monitoring (particularly encompassing poorly represented management actions and taxonomic groups like bats and small mammals) is required to understand whether and where management has worked. Improved implementation of management for threats other than predation is critical to recover Australia's threatened mammals.