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91.
Indoor and ambient concentrations of 21 volatile organic compounds (including 14 hazardous air pollutants) were measured in the homes of nearly 80 western Montana (Missoula) high school students as part of the 'Air Toxics Under the Big Sky' program during the 2004/2005 and 2005/2006 school years. Target analytes were measured using low flow air sampling pumps and sorbent tubes, with analysis of the exposed samples by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). The results reported here present the findings of the first indoor/ambient air toxics monitoring program conducted in a semi-rural valley location located in the Northern Rocky Mountain/Western Montana region. Of all of the air toxics quantified in this study, toluene was found to be the most abundant compound in both the indoor and ambient environments during each of the two school years. Indoor log-transformed mean concentrations were found to be higher when compared with ambient log-transformed mean concentrations at P < 0.001 for the majority of the compounds, supporting the results of previous studies conducted in urban areas. For the air toxics consistently measured throughout this program, concentrations were approximately six times higher inside the student's homes compared to those simultaneously measured directly outside their homes. For the majority of the compounds, there were no significant correlations between indoor and ambient concentrations.  相似文献   
92.
Imidacloprid is a neonicotinoid insecticide with neurotoxic action that, as a possible alternative for commonly used organophosphorus pesticides, has gained registration in about 120 countries for use in over 140 agricultural crops. Only few data are available on its toxicity for soil invertebrates. We therefore assessed the effects of imidacloprid on survival, weight gain, feeding rate, total protein content, glutathione S-transferase activity (GST), and digestive gland epithelial thickness in juveniles and adults of the terrestrial isopod Porcellio scaber. After two weeks of feeding on imidacloprid-dosed food, weight gain (NOEC 5 microg/g dry food) and feeding rate (NOEC 10 microg/g) in juveniles, and feeding rate (NOEC<10 microg/g) and digestive gland epithelial thickness (NOEC<10 microg/g) in adults were most affected. In juveniles induction of GST activity and increase of total protein content per wet animal weight was detected at 5 microg/g dry food, whereas in adults a reduction of GST was observed at 25 microg/g (NOEC 10 microg/g). An estimate of actual intake rates suggests that imidacloprid affects isopods at similar exposure concentrations as insects. The toxicity of imidacloprid was similar to that of the organophosphorus pesticide diazinon, tested earlier using the same methods [Stanek, K., Drobne, D., Trebse, P., 2006. Linkage of biomarkers along levels of biological complexity in juvenile and adult diazinon fed terrestrial isopod (Porcellio scaber, Isopoda, Crustacea). Chemosphere 64, 1745-1752]. At actual environmental concentrations, diazinon poses a higher risk to P. scaber. Due to its increasing use in crop protection and higher persistence in soil, imidacloprid might however, be potentially more dangerous after long-term application. We conclude that toxicity testing with P. scaber provides relevant, repeatable, reproducible and comparable toxicity data that is useful for the risk assessment of pesticides in the terrestrial environment.  相似文献   
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94.
One hundred and five parents and nonparents responded to a questionnaire consisting of evaluative ratings (general evaluation, social status and safety concern) of six familiar residential neighborhoods; ratings of the traffic accident risk children in the age ranges 2–4, 5–6, 7–9 and 10–12 years run in these neighborhoods; and, finally, ratings of the strengths attributed to factors as causes of traffic accidents (environment, children, parents, drivers and chance). Across neighborhoods and age ranges of children, risk perceptions were found to be related to the rated strengths of the causes. Low-traffic volume neighborhoods were perceived as less risky and were attributed as less strong causes than high-traffic volume neighborhoods were. Perceived risk increased with age of child to a maximum, then decreased. The same relationship with age was found for the attributed causes environment and drivers. The strength of parents as cause was rated to decrease while the strength of child as cause was rated to increase with age. Chance was rated as the weakest cause and the rated strength did not vary across neighborhoods or age. Neither parentship nor gender, singly or in combination, had any clear effects. For parents and nonparents alike the general evaluation of the neighborhoods was influenced by safety concern but not by the particular aspect investigated, i.e. perceived traffic accident risk to children.  相似文献   
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96.
Cassia siamea plants growing at two different sites (polluted and non-polluted) on two important roads of Agra city exhibited significant differences in their flowering phenology and floral morphology. The flowering in plants growing at polluted site is delayed and there was a marked reduction in flowering density, flowering period, size of floral parts, pollen fertility, fruit and seed-set. SEM observations revealed the presence of well developed glandular structures and reduction in the number and size of large stomata on the anther surface at polluted site. These changes were found to be closely associated with the extent of air pollution caused mainly by significant in the number of automobiles.  相似文献   
97.
During austral summer 2006, experiments were carried out to evaluate the effects of ultraviolet radiation (UVR, 280–400 nm) on carbon fixation of natural phytoplankton assemblages from Patagonia (Argentina). Surface water samples were collected (ca. 100 m offshore) at mid morning using an acid-cleaned (1 N HCl) dark container. The short-term impact of UVR (measured as radiocarbon incorporation) was immediately assessed by exposing samples to three artificial illumination treatments: PAR (400–700 nm), PAR + UV-A (320–700 nm), and PAR + UV-A + UV-B (280–700 nm). Pico-nanoplankton characterized the assemblages, and taxon-specific pigment fingerprinting combined with CHEMTAX and supplemented with microscopic observations showed varied proportions of diatoms, chlorophytes, and cyanobacteria throughout January–February 2006. Photosynthetic efficiency, as assessed through assimilation numbers, was high [between 4.4 and 10.4 μg C (μg chl-a)−1 h−1], and it was probably favored by the supply of inorganic nutrients from the Chubut River. UVR-induced photoinhibition appeared to be related to the taxonomic composition: in general, higher photoinhibition was observed when diatoms dominated, whereas this was lower when samples were dominated by chlorophytes. Our data suggest that xanthophyll pigments might have provided only limited protection in these already highlighted acclimated assemblages.  相似文献   
98.
Environmental Science and Pollution Research - Heavy metal discharge from anthropogenic sources on open soil surfaces and in natural water bodies poses serious environmental and health concerns. In...  相似文献   
99.
Quality assessment of water is essential to ensure sustainable safe use of it for drinking, agricultural, and industrial purposes. For the same purpose the study was conducted for the samples of water of Sambhar lake city and its adjoining areas. The standard methods of APHA were used to analysis 15 samples collected from hand pumps and tube wells of the specified area. The analytical results show higher concentration of total dissolved solids, electrical conductivity sodium, nitrate, sulfate, and fluoride, which indicate signs of deterioration but values of pH, calcium, magnesium, total hardness, and carbonate are within permissible limits as per WHO standards. From the Hill-piper trilinear diagram, it is observed that the majority of groundwater from sampling stations are sodium?Cpotassium?Cchloride?Csulfate type water. The values of sodium absorption ratio and electrical conductivity of the groundwater were plotted in the US salinity laboratory diagram for irrigation water. Only the one sample fall in C3S1 quality with high salinity hazard and low sodium hazard. Other samples fall in high salinity hazard and high sodium hazard. Chemical analysis of groundwater shows that mean concentration of cation is in order sodium > magnesium > calcium > potassium while for the anion it is chloride > bicarbonate > nitrate > sulfate.  相似文献   
100.
Summary The sources of dark smoke and particulate elemental carbon (PEC) in the London and United Kingdom atmospheres have been estimated from emission inventories. Diesels are responsible for about 60 percent of the dark smoke and 95 percent of the PEC in London, and about 30 percent of the dark smoke and 90 percent of the PEC in the UK. The role of PEC in the soiling of materials is considered. An experimental programme in the Hatfield Tunnel revealed a soiling rate constant of 1.9 yr–1. The socio-economic implications of building soiling are considered.Dr Trudie Mansfield completed her postgraduate training at Middlesex Polytechnic, where her research supervisor, Dr Ron Hamilton, and Bryan Ellis are members of staff in the Urban Pollution Research Centre (address, Bounds Green Road, London N11 2NQ) and Peter Newby is a staff member in the School of Geography (address, Queensway, Enfield EN3 4SF). Trudie Mansfield is a Senior Scientific Officer in the Air Quality Division of the Department of the Environment.  相似文献   
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