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961.
A geo-referenced data set of 12 228 first-time blood lead screening values for Syracuse, NY, children was established for the 4-year period 1992–1996. Soil lead values were measured in a 600 m by 600 m tessellation grid covering the city. The two data sets were merged for evaluation of relationships between them. Strong seasonal variation in blood lead levels suggests the importance of contaminated soils as an exposure source. When the data were aggregated at a large geographic scale (3 km2), a logarithmic model showed an R2 of > 0.65 for the regression of geometric mean blood lead on median soil lead values. Results showed a striking similarity to those obtained by Mielke et al. (1999) for a study in New Orleans, LA, USA. 相似文献
962.
Prashanth MS David M Mathed SG 《Journal of environmental biology / Academy of Environmental Biology, India》2005,26(1):141-144
The toxicity of insecticide cypermethrin to the freshwater fish, Cirrhinus mrigala was studied using static bioassay method. The 96 h LC50 was found to be 5.13 microg/l. Increase in opercular movement, loss of equilibrium, increase in surface behaviour, change in body colour, increase secretion of mucus, irregular swimming activity, rapid jerk movement, 'S' jerky, partial jerk, and aggressiveness were observed in fish exposed to lethal concentration of cypermethrin. But in sub lethal concentration changes were observed from that of lethal and with the approach of 14 and 21 day, fish attained to normalcy. 相似文献
963.
Information about foraging speeds is particularly valuable when the impact of a predator species upon a community of prey has to be defined, as in the case of great cormorants. We measured the swim speed of 12 (six males and six females) free-ranging great cormorants Phalacrocorax carbo, foraging off the Greenland coast during the summer of 2003, using miniaturized data-loggers. Although mean body mass of males was 27% greater than that of females, and mean swim speed of males were 29–57% higher than that of females during foraging phases (but not descent phases) of dives, these differences in speeds were not significant due to high variances. Birds descended to the mean maximum depth of 4.7 m at an average speed of 1.6±0.5 m s−1, a speed similar to that measured in captive cormorants in previous studies. Although bursts of up to 4 m s−1 were recorded, speed usually decreased during the deepest (foraging) phase of dives, being on average 0.8±0.6 m s−1. Speeds measured here should be taken with caution, because the large propeller loggers used to measure speed directly decreased descent speeds by up to 0.5 m s−1 when compared to smaller depth-only loggers. Cormorants in Greenland seem to combine two searching strategies, one requiring low speed to scan the water column or benthos, and one requiring high speed to pursue prey. These two strategies depend on the two main habitats of their prey: pelagic or demersal. 相似文献
964.
David Sillam-Dussès Etienne Sémon Céline Moreau Irena Valterová Jan Šobotník Alain Robert Christian Bordereau 《Chemoecology》2005,15(1):1-6
Summary. The diterpene neocembrene A or (1E,5E,9E,12R)-1,5,9-trimethyl-12-(1-methylethenyl)-1,5,9-cyclotetradecatriene, known as the trail-following pheromone of the advanced Termitidae Nasutitermitinae Nasutitermes exitiosus and Trinervitermes bettonianus, has been identified after SPME-GC/MS as the major component of the trail-following pheromone of the Rhinotermitidae Prorhinotermitinae, Prorhinotermes canalifrons and P. simplex. In all the other Rhinotermitidae studied until now, the major component of their trail pheromones is dodecatrienol ((3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol). This biochemical data further add to the anatomical and molecular characteristics that give a special status to the taxon Prorhinotermes among Rhinotermitidae. In Prorhinotermes canalifrons and P. simplex, neocembrene A was the only secretory compound specific to the sternal gland surface that could be detected after SPME. It elicited orientation as well as recruitment behavioral effects. However, the comparison of the respective biological activities triggered by neocembrene A and by sternal gland secretion suggests that minor components of the latter are acting in synergy with neocembrene A. 相似文献
965.
Stephen C. Pratt Eamonn B. Mallon David J. Sumpter Nigel R. Franks 《Behavioral ecology and sociobiology》2002,52(2):117-127
When its nest is damaged, a colony of the ant Leptothorax albipennis skillfully emigrates to the best available new site. We investigated how this ability emerges from the behaviors used by ants to recruit nestmates to potential homes. We found that, in a given emigration, only one-third of the colony's workers ever recruit. At first, they summon fellow recruiters via tandem runs, in which a single follower is physically led all the way to the new site. They later switch to recruiting the passive majority of the colony via transports, in which nestmates are simply carried to the site. After this switch, tandem runs continue sporadically but now run in the opposite direction, leading recruiters back to the old nest. Recruitment accelerates with the start of transport, which proceeds at a rate 3 times greater than that of tandem runs. The recruitment switch is triggered by population increase at the new site, such that ants lead tandem runs when the site is relatively empty, but change to transport once a quorum of nestmates is present. A model shows that the quorum requirement can help a colony choose the best available site, even when few ants have the opportunity to compare sites directly, because recruiters to a given site launch the rapid transport of the bulk of the colony only if enough active ants have been "convinced" of the worth of the site. This exemplifies how insect societies can achieve adaptive colony-level behaviors from the decentralized interactions of relatively poorly informed insects, each combining her own limited direct information with indirect cues about the experience of her nestmates. 相似文献
966.
Margaret E. Farago Iain Thornton Nicola D. White Inge Tell Maj‐Britt Mårtensson 《Environmental geochemistry and health》1999,21(1):67-82
Scandinavia has one secondary lead smelter that recycles lead from approximately 85% of used car batteries in Scandinavia and which has been active since the 1940s. The smelter, situated in Landskrona, has undergone a comprehensive clean up programme during the last decade, during which time production has doubled, while at the same time discharges of dust and lead to the atmosphere have decreased.Top and depth soil samples were taken on a 0.5km×0.5Km grid throughout the city of Landskrona, which covers an area of approximately 15km2. Samples were analysed by ICPAES for a number of elements including Pb, Zn, Cu, Cd, As, Sb and Hg. Road dust samples from selected sites were collected and similarly analysed. Blood samples were taken from 37 volunteer schoolchildren (aged 8–11) from two schools in Landskrona. House dust samples were taken from each child's home. Soil samples were taken from homes which had gardens, public and school play areas. Elevated heavy metal concentrations were found in close proximity to the secondary lead smelter, and this soil enrichment influences the whole of the town, modified to some extent by the prevailing wind. The smelter does not influence the soil lead concentration at distances greater than 3.5km, where the soil reflects the background value for the area.Road dust samples also show decreases in lead concentrations with distance from the smelter. The average level of lead in house dust was considerably lower than that found in Birmingham, UK. Blood lead levels in the child population ranged from 1.5–5.1gdl–1, with a mean of 3.05gdl–1, showing a distinct decrease from those measured in 1978–82. No significant difference in blood lead concentrations with distance of the home from the smelter, nor between attenders at the two schools was revealed in the limited number of children studied. 相似文献
967.
In this study two sites were selected in order to investigate groundwater contamination and spatial relationships among groundwater quality, topography, geology, landuse and pollution sources. One site is the Asan area, an agricultural district where pollution sources are scattered and which is mainly underlain by granite of Cretaceous age. The other site is the Gurogu area of Seoul city, an industrial district where an industrial complex and residential areas are located and which is mainly underlain by gneiss of Precambrian age. Groundwater samples collected from these districts were analysed for chemical constituents. An attribute value files of chemical constituents of groundwater and the spatial data layers were constructed and pollution properties were investigated to establish out spatial relationships between the groundwater constituents and pollution sources using geographic information systems (GIS).Relatively high contents of Si and HCO3
– in the groundwater from the Asan area reflect the effect of water–rock interaction whereas high contents of Cl–, NO3
– and Ca2+ in the groundwater from the Gurogu area are due to the pollution of various sources. The significant seasonal variation of SiO2, HCO2
– and Ca2+ contents, and that of Ca2+ content were observed in the Asan and the Gurogu areas, respectively. Seasonal variation of pollutants such as Cl–, NO3
– and SO4
2– was not observed in either area. Pollution over the critical level of the Korean drinking water standard has been investigated from 15 sampling sites out of 40 in the Asan area, and 33 sampling sites out of 51 in the Gurogu area. Pollution by NO3
–, Cl–, Fe2+, Mn2+, SO4
2– and Zn2+ in the groundwater from the industrial district (Gurogu area) and that of NO3
, SO4
2– and Zn2+ in the groundwater from the agricultural district (Asan area) were observed. The principal pollutant in both areas is NO3
–. Deep groundwater from the Asan area is not yet contaminated with NO3
– except for one site, but most of the shallow groundwater site occurring near the potential point sources is seriously contaminated. From the result of buffering analysis, it seems clear that factories and stock farms are the principal pollution sources in the Asan area. The groundwater from the Gurogu area has already been seriously polluted considering the fact of NO3
– contamination of deep groundwater. Chlorine pollution of shallow groundwater in the Gurogu area was also observed. Spatial relationship between pollution level and its source was clarified in this study by using GIS, which will be applicable to the effective management of groundwater quality. 相似文献
968.
The US Environmental Protection Agency’s National Center for Environmental Assessment is finalizing its updated approach to assessing the health risks from direct and indirect exposure to combustion emissions. The prior 1990 Indirect Exposure Methodology has been used frequently in the early part of this decade, while the new methodology considers more pathways for agent transfer and exposure. This advanced methodology is not limited to exposure from combustion emissions as the approach lends itself to assessing indirect exposure to other agents in various exposure scenarios. The purpose of this presentation is to alert the user community to the new methodology and discuss its impacts on risk assessment. A brief overview of the exposure pathways, along with the inherent uncertainties of the MPE and the risk characterization, are presented. Other associated documentation is presented and referenced. The paper concludes with a discussion of the planned implementation of the MPE and the Agency program guidance for use with RCRA combustor permitting and risk assessments. 相似文献
969.
David Gerard 《Resources Policy》1998,24(4):251-264
This paper applies a property rights framework to federal mineral lands in the western United States from the enactment of the Mining Law in 1872 until the enactment of the Mineral Leasing Act for fossil fuels in 1920. There are two principal findings. First, the Mining Law appears to have been an effective means for assigning rights to mineral stocks on public lands (at least through 1920). This conclusion is supported by evidence from claim disputes in the West. Second, the impetus for the Mineral Leasing Act did not derive from the different physical characteristics of hardrock minerals and petroleum. The relevance of these conclusions to contemporary mineral policy is also discussed. 相似文献
970.
Stakeholder groups, defined according to their transcendent values, have different concepts of sustainability. Their prioritizations of individual, family, collective, and local and global environmental issues also differs. Given this, the metrics required for a given sustainable development path are subjective. Therefore, the questions of who should define ecometrics, their transparency, number, state of aggregation, standardization, and benchmarking are questions that require an enfranchised multi-stakeholder debate. At present, corporations have been asked to bear the burden of environmental reporting and eco-indicators have been established to account for material intensity, energy consumption and waste or toxic releases, among other factors. However, the links among these local-, product-, or service-based microecometrics and global states such as temperatures or atmospheric concentrations have yet to be established. The relationship of macroecometrics to individual definitions of sustainable development also has not been addressed. This article summarizes four plenary lectures given at ECOMETRICS '98 in Lausanne, Switzerland. The workshop involved forty participants from industry, academic and government organizations representing seven countries and three continents. 相似文献