Mercury in United Kingdom topsoils; concentrations, pools, and Critical Limit exceedances

The median total mercury concentration in 898 UK rural topsoils, sampled between 1998 and 2008, was 0.095 μg g⁻¹. Approximate adjustment for unreactive metal produced an estimate of 0.052 μg g⁻¹ for reactive Hg. The highest concentrations were in the north and west, where organic-rich soils with low bulk densities dominate, but the spatial pattern was quite different if soil Hg pools (mg m⁻²) were considered, the highest values being near to the industrial north of England and London. Possible toxic effects of Hg were best evaluated by comparison with soil Critical Limits expressed as ratios of Hg to soil organic matter, or soil solution Hg²⁺ concentrations, estimated by chemical speciation modelling. Only a few percent of the rural UK soils showed exceedance, and this also applied to rural soils from the whole of Europe. UK urban and industrial soils had higher Hg concentrations and more cases of exceedance.     

Temporal Analysis of Airborne Particulate Matter Reveals a Dose-Rate Effect on Mortality in El Paso: Indications of Differential Toxicity for Different Particle Mixtures

Abstract

One of two topics explored is the limitations of the daily average in summarizing pollutant hourly profiles. The daily average of hourly measurements of air pollutant constituents provides continuity with previous studies using monitoring technology that only provided the daily average. However, other summary statistics are needed that make better use of all available information in 24-hr profiles. The daily average reflects the total daily dose, obscuring hourly resolution of the dose rate. Air pollutant exposures with comparable total daily doses may have very different effects when occurring at high levels over a few hours as opposed to low levels over a longer time. Alternative data-based choices for summary statistics are provided using principal component analysis to capture the exposure dose rate, while preserving ease of interpretation. This is demonstrated using the earliest hourly particle concentration data available for El Paso from archived records of particulate matter (PM)₁₀. In this way, a significant association between evening PM₁₀ exposures and nonaccidental daily mortality is found in El Paso from 1992 to 1995, otherwise missed using the daily average. Secondly, the nature and, hence, effects of particles in the ambient aerosol during El Paso sandstorms is believed different from that of particles present during stillair conditions resulting from atmospheric temperature inversions. To investigate this, wind speed (ws) is used as a surrogate variable to label PM₁₀ exposures as Low-ws (primarily fine particles), High-ws (primarily coarse particles), or Mid-ws (a mixture of fine and coarse particles). A High-ws evening is significantly associated with a 10% lower risk of mortality on the succeeding third day, as compared with comparable exposures at Low- or Mid-ws. Although this analysis cannot be used to form firm conclusions because it uses a very small data set, it demonstrates the limitations of the daily average and suggests differential toxicity for different particle compositions.     

Dissolved inorganic nitrogen budget for a forested catchment at Beddgelert, North Wales

An input-output budget for dissolved inorganic-N in a small forested catchment in North Wales is presented. From 1982 to 1990, bulk precipitation inputs averaged 10.3 kg ha(-1) year(-1), whereas throughfall inputs in 1983-1984 were 20.3 kg ha(-1) year(-1). Streamwater outputs were consistently larger than bulk precipitation inputs, averaging 14.6 kg ha(-1) year(-1). Inorganic-N in the forest stream was predominantly nitrate and concentrations were substantially higher than in a nearby moorland stream. Both streams showed seasonal trends in nitrate concentration, with highest concentrations occurring in summer in the forest stream but in winter in the moorland stream. Nitrate concentration in the forest stream increased with increasing soil temperature up to approximately 7 degrees C and decreased at higher temperatures. Nitrification is thought to be responsible for nitrate production at temperatures both below and above 7 degrees C, but root uptake becomes significant only at the higher temperatures. In the forest, dry deposition and cloudwater inputs of inorganic-N are responsible for increased nitrogen fluxes in throughfall compared with wet deposition. Mineralization and nitrification in excess of plant needs causes the organic soil horizons to act as a net source of dissolved inorganic-N. Nitrogen transformations in the soil lead to soil acidification at a rate of 1.0 keq ha(-1) year(-1).     

Source apportionment of Phoenix PM2.5 aerosol with the Unmix receptor model

The multivariate receptor model Unmix has been used to analyze a 3-yr PM2.5 ambient aerosol data set collected in Phoenix, AZ, beginning in 1995. The analysis generated source profiles and overall average percentage source contribution estimates (SCEs) for five source categories:gasoline engines (33 +/- 4%), diesel engines (16 +/- 2%), secondary SO4(2-) (19 +/- 2%), crustal/soil (22 +/- 2%), and vegetative burning (10 +/- 2%). The Unmix analysis was supplemented with scanning electron microscopy (SEM) of a limited number of filter samples for information on possible additional low-strength sources. Except for the diesel engine source category, the Unmix SCEs were generally consistent with an earlier multivariate receptor analysis of essentially the same data using the Positive Matrix Factorization (PMF) model. This article provides the first demonstration for an urban area of the capability of the Unmix receptor model.     

Male morphology and behavior correlate with reproductive success in the American redstart (Setophaga ruticilla)

Summary In a population of American redstarts (Setophaga ruticilla), we determined whether a relationship exists between seasonal reproductive success (RS) and a variety of male and female morphological and behavioral characters including plumage and male song. Adult males differ dramatically in plumage from yearling males and also exhibit variable amounts of black on their breast (bib size). Adult males were more successful than yearlings in terms of the number of eggs laid by their females. Among adult males, those with smaller bibs (less black) had females that laid more eggs, and produced more hatchlings and more fledglings. We found no evidence to indicate that this result was a consequence of territory quality. We examined a number of features of song but none alone was a predictor of RS; however, one song feature (rare repeat song) correlated with bib size. When bib size and rare repeat song were analyzed simultaneously, both were found to relate to RS. No female features were predictors of RS, but females arriving earlier at the breeding site mated with males with smaller bibs. The evidence is consistent with the view that plumage of redstarts may be used as a basis for female choice. Offprint requests to: R.E. Lemon     

Water quality assessment programs in Australia deciding what to measure,and how and where to use bioindicators

Effective water quality assessment programs require the formulation of common objectives between managers who are making decisions and scientists who are obtaining the information on which those decisions are to be made. The data collected must be apropriate for use in the decision making process. After the objectives have been formulated a number of testable hypotheses can be proposed and evaluated in terms of what information is required for decision making.From a management perspective it is important to know if an impact occurs and what management strategy to adopt to reduce or eliminate the impact. When bioaccumulators are used to indicate environmental quality the organisms proposed need to be fully evaluated before being used. Communities, which are often used to assess levels of impact, have the capacity to assimilate pollutants and they will function under pollutant stress. Thus managers need to make value judgements about when a community structure or function has shifted from acceptable to adverse. Bioassays in which the effects of pollutants on growth, biochemistry and behaviour are measured, give an indication of the sub-lethal effects of a pollutant, but it is difficult to set meaningful levels that are not to be exceeded for use by managers.Difficulties in using chemical and biological data mainly arise from a lack of appreciation of environmental heterogeneity. The data obtained must meet the needs for statistically testing hypotheses. Before programs can be designed to meet statistical needs the potential sources of variability must be considered. Once the minimum differences that are seen as important have been determined, the number of replicates needed can be calculated. Data verification is also needed, as if the validity of data is questioned, so will any decisions that have been made based on those data. Finally programs should be designed to minimize the sampling effort/cost to meet the objectives.     

Quantitative tools for implementing the new definition of significant portion of the range in the U.S. Endangered Species Act

In 2014, the Fish and Wildlife Service (FWS) and National Marine Fisheries Service announced a new policy interpretation for the U.S. Endangered Species Act (ESA). According to the act, a species must be listed as threatened or endangered if it is determined to be threatened or endangered in a significant portion of its range (SPR). The 2014 policy seeks to provide consistency by establishing that a portion of the range should be considered significant if the associated individuals’ “removal would cause the entire species to become endangered or threatened.” We reviewed 20 quantitative techniques used to assess whether a portion of a species’ range is significant according to the new guidance. Our assessments are based on the 3R criteria—redundancy (i.e., buffering from catastrophe), resiliency (i.e., ability to withstand stochasticity), and representation (i.e., ability to evolve)—that the FWS uses to determine if a species merits listing. We identified data needs for each quantitative technique and considered which methods could be implemented given the data limitations typical of rare species. We also identified proxies for the 3Rs that may be used with limited data. To assess potential data availability, we evaluated 7 example species by accessing data in their species status assessments, which document all the information used during a listing decision. In all species, an SPR could be evaluated with at least one metric for each of the 3Rs robustly or with substantial assumptions. Resiliency assessments appeared most constrained by limited data, and many species lacked information on connectivity between subpopulations, genetic variation, and spatial variability in vital rates. These data gaps will likely make SPR assessments for species with complex life histories or that cross national boundaries difficult. Although we reviewed techniques for the ESA, other countries require identification of significant areas and could benefit from this research.     

城市道路绿化带不同植物叶片附尘对大气污染的磁学响应

对上海市金沙江路两侧绿化带内24个常绿植物叶片样品进行了磁性与重金属测试,以探讨城市道路绿化带不同植物叶片附尘对大气污染的磁学响应.结果表明,χ、SIRM值分别在（4～59）×10-8m3.kg-1和（496～6 114）×10-6Am2.kg-1之间变化,S-300 mT在89%～98%之间变动.所有植物样品中χARM/χ〈4,χARM/SIRM〈30×10-5mA-1.磁性参数表明,植物叶片附尘以亚铁磁性矿物为主,磁性矿物颗粒以假单畴（PSD）-多畴（MD）为主.重金属元素Zn、Cu、Pb含量与反映亚铁磁性矿物含量的χ、SIRM、χARM呈显著正相关,可以将磁性参数SIRM作为叶片重金属元素的替代指标.推荐在上海地区广泛种植的广玉兰作为道路植物污染的指示植物。     

上海市免费公园中老年游客行为及满意度特征调查

中老年游客是免费公园游客人群的主要群体,以上海市27座免费公园为例,分析中老年两年龄段游客行为特征,以及其对公园设施服务的重要性和满意度。结果表明:中年游客具有择园路程范围广,公共交通利用率高,来园频率低,入园时间晚,喜爱亲子活动,停留时间短等特征;而老年游客则表现出偏爱短距离公园,以步行为主,来园频率高,入园时间早,倾向运动健身,停留时间长等特征。两年龄段游客对公园满意度评价总体相近,均认为绿化、卫生状况和安全性,以及景点、厕所和无障碍设施设置是影响游客来园的关键因子,前3项令游客满意,而后3项却达不到期望。针对两年龄段游客不同的行为和满意度特征,对免费公园的经营管理提出建议。     

Siliceous nanoplankton I. Newly discovered cysts from the Gulf of Alaska

Siliceous nanoplankton in the size range 2.5 to 5.5 m and of a type hitherto undescribed are reported from Eastern Subarctic water samples. Nine distinct cell types were recognizable, each possessing an unusual tetrahedral symmetry, resulting from the arrangement of 8 siliceous plates. Since the cells were abundant (maximum concentration of about 7×10⁵ cells 1^-1) and were distributed over a wide oceanic area (136° to 149°W), they could well play an important role in the food web in Subarctic seas. Similar cells were found simultaneously in Antarctic waters (see following paper: Silver et al., 1980), where they were as abundant and widespread as in the Subarctic. Evidence that the siliceous forms are likely a cyst stage and that they may be part of the life cycle of species of siliceous oceanic choanoflagellates is presented.Contribution No. 1149 from the Department of Oceanography, University of Washington