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321.
Water samples were collected between 1999 and 2000 from wetlands in Minnesota that contained malformed frogs. The water samples were analyzed for 14 minerals/ions and screened for the presence of biologically active compounds using Xenopus laevis. Results indicated that water from two sites, CWB and ROI2, induced severe retardation with embryo lengths reduced 20% after 96 hr of development. The developmental delay observed with water from ROI2 was alleviated by supplementation with sodium, while both sodium and potassium alleviated the developmental delay observed with water whose mineral content mimicked that of CWB. Seasonal fluctuations in the sodium and potassium content at ROI2 and NEY correlated with changes in the rates of Xenopus development. Xenopus embryos reared on water from ROI2 for 120 hr displayed gut malformations not present in embryos reared on a synthetic media designed to mimic the mineral content of the water from ROI2. Embryos reared on water from ROI2 supplemented with minerals at levels comparable to that routinely employed in the rearing of Xenopus were neither retarded nor malformed. It is proposed that climate driven hydrology may influence the mineral composition at selected wetlands and delay development which may alter window(s) of susceptibility towards biologically active agents and the occurrence of malformed frogs.  相似文献   
322.
Public opposition to the siting of waste facilities has been partly explained by a failure to directly involve communities in fundamental policy decisions about waste management. Public participation at the local level is primarily reactive, based upon the premise of consultation on preferred strategies rather than direct involvement in their derivation. This paper presents the findings of a study into the effectiveness of a more proactive community involvement programme adopted by one English county council. The paper suggests some opportunities and barriers to public involvement in waste management strategy development and the potential effectiveness of consensus-building approaches.  相似文献   
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324.
Environmental investigations have been conducted at 23 military firing ranges in the United States and Canada. The specific training facilities most frequently evaluated were hand grenade, antitank rocket, and artillery ranges. Energetic compounds (explosives and propellants) were determined and linked to the type of munition used and the major mechanisms of deposition.  相似文献   
325.
Stormwater ponds have become common features of modern development and often represent significant amounts of open space in urbanized areas. Although stormwater ponds may provide habitat for wildlife, factors responsible for producing variation in wildlife use of ponds have received limited attention. To investigate the role of variation in species tolerances of pollutants in structuring pond-breeding amphibian assemblages, we exposed species tolerant (Bufo americanus) and not tolerant (Rana sylvatica) of urbanization to pond sediments in laboratory microcosms. Pond microcosms had elevated sediment metal levels and chloride water concentrations. Among R. sylvatica embryos, exposure to pond sediments resulted in 100% mortality. In contrast, B. americanus embryos and larvae experienced only sublethal effects (i.e., reduced size at metamorphosis) due to pond sediment exposure. Our results suggest variation in pollutant tolerance among early developmental stages of amphibians may act in concert with terrestrial habitat availability to structure amphibian assemblages associated with stormwater ponds.  相似文献   
326.
Thermochemical biomass gasification, followed by conversion of the produced syngas to fuels and electrical power, is a promising energy alternative. Real-world characterization of particulate matter (PM) and other contaminants in the syngas is important to minimize damage and ensure efficient operation of the engines it powers and the fuels created from it. A dilution sampling system is demonstrated to quantify PM in syngas generated from two gasification plants utilizing different biomass feedstocks: a BioMax?15 Biopower System that uses raw and torrefied woodchips as feedstocks, and an integrated biorefinery (IBR) that uses rice hulls and woodchips as feedstocks. PM2.5 mass concentrations in syngas from the IBR downstream of the purification system were 12.8–13.7 μg·m−3, which were significantly lower than the maximum level for catalyst protection (500 μg·m−3) and were 2–3 orders of magnitude lower than those in BioMax?15 syngas (2247–4835 μg·m−3). Ultrafine particle number concentration and PM2.5 chemical constituents were also much lower in the IBR syngas than in the BioMax?15. The dilution sampling system enabled reliable measurements over a wide range of concentrations: the use of high sensitivity instruments allowed measurement at very low concentrations (∼1 μg·m−3), while the flexibility of dilution minimized sampling problems that are commonly encountered due to high levels of tars in raw syngas (∼1 g·m−3).  相似文献   
327.
Abstract

This paper examines controversy during the 2001 foot-and-mouth outbreak after mass carcass burial sites were selected at two sites in northeast England, and focuses on shortcomings in public consultation surrounding the carcass disposal policy. The slaughter of six million animals necessitated a national disposal strategy on a hitherto unknown scale. The belated decision to concentrate carcass disposal in a small number of mass burial sites provoked more opposition in the two ex-mining localities selected in the northeast than anywhere else. In both cases local liaison committees were established to manage dialogue between residents and public authorities. We argue that, although seen by the authorities primarily as a vehicle for risk communication and public reassurance, for residents these functioned chiefly as a vehicle for holding public authorities to account. These divergent purposes were overshadowed by the chaotic circumstances in which the early stages of the mass burial policy were implemented, and the way in which the carcass disposal policy was dictated by the operation of the slaughter policy, whose draconian form precluded any but the most cursory public consultation.  相似文献   
328.
Environmental Science and Pollution Research - Sharks are top predators and play an important role in the regulation of marine ecosystems at lower trophic position. Mustelus californicus, Sphyrna...  相似文献   
329.
Characteristics of Composition B particles from blow-in-place detonations   总被引:1,自引:0,他引:1  
We sampled residues from high-order and low-order blow-in-place detonations of mortars and projectiles filled with Composition B (Comp B), a TNT and RDX mixture. Our goals were to (1) characterize the types of explosive particles, (2) estimate the explosive 'footprint' for different munitions, and (3) estimate the mass of Comp B remaining after each detonation. The aerial deposition of Comp B particles helps estimate how large of an area is contaminated by a low-order detonation and how best to sample residue resulting from different rounds. We found that the high-order detonations deposited microgram to milligram quantities whereas the low-order detonations deposited gram quantities of Comp B. For the high-order detonations the concentration of Comp B in the residue decreased as a function of distance from the blast. The low-order tests scattered centimeter-sized chunks and millimeter-sized or smaller particles of Comp B. The chunks were randomly scattered whereas the number of millimeter-sized particles decreased with distance from the detonation. For both high- and low-order detonations we found that the smaller munitions deposited less Comp B than the larger munitions and deposited it closer to the detonation point.  相似文献   
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