Mercury accumulation in soils and plants in the Almadén mining district, Spain: one of the most contaminated sites on Earth

Although mercury (Hg) mining in the Almadén district ceased in May 2002, the consequences of 2000 years of mining in the district has resulted in the dissemination of Hg into the surrounding environment where it poses an evident risk to biota and human health. This risk needs to be properly evaluated. The uptake of Hg has been found to be plant-specific. To establish the different manners in which plants absorb Hg, we carried out a survey of Hg levels in the soils and plants in the most representative habitats of this Mediterranean area and found that the Hg concentrations varied greatly and were dependent on the sample being tested (0.13–2,695 μg g⁻¹ Hg). For example, the root samples had concentrations ranging from 0.06 (Oenanthe crocata, Rumex induratus) to 1095 (Polypogon monspeliensis) μg g⁻¹ Hg, while in the leaf samples, the range was from 0.16 (Cyperus longus) to 1278 (Polypogon monspeliensis) μg g⁻¹ Hg. There are four well-differentiated patterns of Hg uptake: (1) the rate of uptake is constant, independent of Hg concentration in the soil (e.g., Pistacia lentiscus, Quercus rotundifolia); (2) after an initial linear relationship between uptake and soil concentration, no further increase in Hg_plant is observed (e.g., Asparagus acutifolius, Cistus ladanifer); (3) no increase in uptake is recorded until a threshold is surpassed, and thereafter a linear relationship between Hg_plant and Hg_soil is established (e.g., Rumex bucephalophorus, Cistus crispus); (4) there is no relationship between Hg_plant and Hg_soil (e.g., Oenanthe crocata and Cistus monspeliensis). Overall, the Hg concentrations found in plants from the Almadén district clearly reflect the importance of contamination processes throughout the study region.     

基于电荷监测技术预测矿山动力灾害试验研究

为提高矿山动力灾害预测准确率,应用自主研制的电荷传感器,将标准煤样置于三轴压力室内进行应力-电荷试验。分析围压对煤样压缩破坏过程中电荷信号的影响。结合现场测试,揭示工作面开挖过程中煤体应力与煤壁表面感应电荷的时间和空间变化规律。试验结果表明,煤体压缩过程中电荷信号的变化与煤体所处的应力水平关系密切,处于应力集中区域和应力松弛区域的煤体有明显脉冲状电荷信号,原始应力区电荷信号平稳,电荷信号的变化超前于煤体应力的变化,围压对电荷信号有延缓、强化的作用。     

联网激光雷达的观测性能综合平行比对

激光雷达以其高精度的探测能力在大气污染研究中得到了广泛应用。由于生产厂家和反演算法等的差异,激光雷达观测数据的质量参差不齐。笔者利用2013年11月和2014年3月2种不同型号激光雷达(高频激光雷达和微脉冲激光雷达) 532 nm波段的气溶胶消光系数和气溶胶自动观测网(AERONET)光学厚度数据,对2部雷达在不同空气质量下的观测性能进行综合对比。结果表明:2部雷达在不同空气质量条件下探测效果不同,空气质量为优和良时,2部雷达的消光系数比较一致,偏差主要在1 km以下;随着污染加剧,2部雷达在1 km以下的偏差先减小后增大,1 km以上的偏差随高度增大。与AERONET的光学厚度相比,高频激光雷达在轻度污染和严重污染时相对误差较小(3. 23%和26. 75%);微脉冲激光雷达在良和轻度污染时相对误差较小(40. 00%和25. 81%)。2部雷达设备的差异和重污染时不利的气象条件是影响雷达表现的重要原因。该研究作为全国激光雷达联网的前期工作,为全国激光雷达数据的综合应用提供了参考。     

Light levels used during feeding by primate species with different color vision phenotypes

The intensity of available light is important in determining how well a diurnal animal can distinguish color. Primates with different types of color vision may exhibit behaviors that maximize visual contrast during critical activities such as feeding. We hypothesized that (1) trichromatic taxa will feed in a wide range of light conditions because color constancy permits stabilized color appearance across changes in illumination, and (2) that taxa with a high proportion of dichromatic individuals will tend to feed at higher light levels to increase color contrast. We recorded light levels during feeding bouts of seven primate taxa with varying degrees of color vision: the dichromatic Lemur catta, two polymorphic species, Propithecus v. verreauxi and Ateles geoffroyi, and the routine trichromats, Alouatta palliata, Colobus guereza, Piliocolobus badius, and Cercopithecus ascanius. Results were equivocal for our hypotheses. While routinely trichromatic taxa used varying light levels, the pattern of results did not differ from the dichromatic Lemur catta. However, polymorphic taxa not only sought the highest light, but females, which are the only individuals in polymorphic taxa that can be trichromatic, fed in higher light levels than males when eating non-green foods. This result is consistent with selection operating to maintain a balanced polymorphism in these taxa, though the connection between light levels and color vision type for the females is unclear. Our results further suggest that trichromatic vision may afford a selective advantage because it permits foraging under a greater range of light levels.     

Mineral, chemical and radiological investigation of a black sand at Touzla Cape, near Thessaloniki, Greece

A black-sand formation located at Touzla Cape, near Thessaloniki city, Greece, was investigated using optical microscopy, powder-XRD, SEM-EDS, INAA and in-situ -ray spectrometry. This black sand is mainly composed of ilmenite, magnetite, garnet, zircon and rutile. Also present, in minor or trace amounts, are quartz, sphene, pyroxenes, sillimanite, feldspars, biotite, haematite, tourmaline, chromite, niobian-rutile and pyrrhotite. Niobian-rutile and pyrrhotite were found as inclusions in ilmenite and magnetite respectively. The radioactivity measurements indicated contributions of the uranium and thorium radioactive series and of 40K and 137Cs, and the maximum value of the total absorbed dose rate in air was found to be 62, 172, 8 and 2 nGy h-1 respectively. The main radioactivity of the uranium and thorium series is attributed to the fractions of zircon (304 µg Th g-1 and 157 µg U g-1), of ilmenite (89 µg Th g-1) and to a lesser extent to the fraction of garnet (5 µg Th g-1). The zircon fraction also contained 5076 µg Hf g-1. Some minerals and elements (Ti, Zr, Hf, Th, U) contained in the black sand could be of potential economic value. The high proportions of monomineralic grains along with the variations observed in mineral phases, in colour, in sphericity, in roundness, in grain size, in composition and in mineral inclusions, imply that the minerals and grains were subjected to several cycles of weathering and sedimentation, as well as being derived from multiple source rocks and areas.     

Effect of Pb,Cd and Cu on survival and development of Culex quinquefasciatus (Diptera: Culicidae)

ABSTRACT

The present research aimed to determine the lowest levels of three heavy metals (Pb, Cd and Cu) to which the larvae of Southern House Mosquito, Culex quinquefasciatus are susceptible in water. The study also aimed to investigate the effects of these heavy metals on the development of Cx. quinquefasciatus at concentrations set by Pakistan Environmental Protection Agency (Pak-EPA) as permissible levels for liquid industrial effluents. The 2nd instar larvae of Cx. quinquefasciatus were exposed to different concentrations of Pb, Cd and Cu and their effects on oviposition preference, egg hatching rate and larval development were studied. The LC₅₀ values of Pb, Cd and Cu were 12.6, 6.3 and 2.6?ppm, respectively. Gravid female mosquito adults deposited a significantly lower number of egg rafts in containers containing 0.50?ppm Pb or 1.0?ppm Cu in water. Each of the heavy metals in water resulted in significantly (p?<?0.05) lower egg hatching rate, prolonged time to pupation, lower pupation rate, prolonged time to adult emergence, lower adult emergence rate and higher female to male ratio. It is concluded that the 2nd instar larvae of Cx. quinquefasciatus are susceptible to Pak-EPA permissible levels of Pb, Cd and Cu in municipal and liquid industrial effluents.     

成都市大气降尘放射性水平分析

本文介绍了成都市大气降尘放射性水平的监测结果。发现降尘中除有少量天然核素外,还尚存有以往大气层核试验释放的裂变核素９０Ｓｒ和１３７Ｃｓ。平均年沉降量９０Ｓｒ为１０２Ｂｑ·ｍ－２·Ｙ－１,１３７Ｃｓ为１３１Ｂｑ·ｍ－２·Ｙ－１。由大气９０Ｓｒ和１３７Ｃｓ沉降所致公众辐射剂量为１６８μＳｒ·ａ－１,是限值的２‰。所以,降尘中放射性造成的辐射影响是很小的。     

白洋淀几种不同食性鱼类对六六六、DDT的富集

对白洋淀几种不同食性鱼体内六六六和ＤＤＴ残留量分析表明，草食性鱼体内农药残留量最少，六六六含量为５９．３μｇ／ｋｇ，ＤＤＴ含量为２９．６μｇ／ｋｇ；其次是杂食性鱼类，六六六含量为９０．４μｇ／ｋｇ，ＤＤＴ含量为１０８．５μｇ／ｋｇ；肉食性鱼体内农药残留量最高，六六六含量为１１０．７μｇ／ｋｇ，ＤＤＴ含量为１２４．４μｇ／ｋｇ。鱼体对ＤＤＴ的浓缩因子为３１１～１２４４，明显高于六六六的１７７～３６８。鱼体内ＢＨＣ４种异构体的残留顺序为δ＞α＞γ＞β，与其在水体中的比例α＞γ＞δ＞β略有不同。鱼体内ＤＤＴ主要以代谢物ｐ，ｐ＇－ＤＤＥ的形式存在，但个别样品中少量的ｐ，ｐ＇－ＤＤＤ及ｏ，ｐ＇－ＤＤＴ的检出，表明白洋淀水生生态系统最近受到ＤＤＴ的轻度污染。本项研果与１９７５～１９７７年检测结果进行比较；白洋淀鱼体内六六六残留量显著下降，下降率为１５．８％～７９．２％；ＤＤＴ残留量却明显增加（草食性鱼类除外），增加率约为４７．８％～９７．８％。     

BED含氧燃料在不同海拔下对柴油机PM和NOx排放的影响

为研究生物柴油-乙醇-柴油(简称为BED)含氧燃料在不同海拔下对柴油机微粒(PM)和氮氧化物(NO_x)排放的影响,在一台高压共轨柴油机上分别燃用纯柴油和BED含氧燃料,在两种大气压力(81和100 k Pa)下进行了排放试验研究.结果表明,燃用纯柴油和B15E5(15%生物柴油+5%乙醇+80%柴油,体积比)燃料后,在中、低负荷时的PM排放在高气压下基本高于低气压下,最高增幅分别达到26.2%和19.0%;在全负荷时的PM排放在高气压下降低,最高降幅分别达到6.1%和17.0%.燃用B25E5(25%生物柴油+5%乙醇+70%柴油,体积比)燃料后,PM排放在高气压下降低.燃用纯柴油后,柴油机在高气压下的NO_x排放低于低气压下;燃用B15E5和B25E5含氧燃料后,在中、低负荷下的NO_x排放在高气压下降低,在全负荷下的NO_x排放在高气压下升高.在中、低负荷下NO_x排放最高降幅分别达到12.1%和15.3%;在全负荷下,NO_x排放最高增幅分别达到6.5%和5.8%.在不同大气压力下,柴油机燃用纯柴油和BED含氧燃料后,PM与NO_x排放均呈现明显的trade-off关系.相比于在低气压下,随负荷增加引起的PM排放降幅和NO_x排放增幅在高气压下增加.     

A Rapid Response Survey to Characterize the Impacts of the 2017 High Water Event on Lake Ontario

In the spring and summer of 2017, communities along the Lake Ontario shoreline suffered from the worst flood event on record. In late May, daily water levels reached their highest point in over 100 years, and flooding continued throughout much of the summer as lake levels slowly declined, with inundation and erosion significantly impacting shoreline homes and businesses. In this work, we present results from a rapid response online survey of property owners along the New York Lake Ontario shoreline to quantify the perceived flood impacts of the 2017 extended high water event. The survey focused on the degree and spatial distribution of inundation and erosion; the duration and drivers of inundation; the associated damages to different property features, with an emphasis on shoreline protection; and the degree of disruption to business and other activities and services. Photographic documentation of inundation extent and property damage also was provided by survey respondents. We demonstrate the potential utility of this dataset by characterizing key features of inundation and erosion impacts across the shoreline, and by using classification and regression trees to explore the predictability of inundation and erosion based on property characteristics. This work is part of a larger effort to develop models of inundation and erosion that can support flood impact assessments across the shoreline and help communities better prepare for future extended high water events.