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81.
Collection of water-level recovery data is a common practice for pumping tests. The resulting data can provide some of the most useful information from the tests, but are rarely used to their full value. van der Kamp (1989) proposed a general method that uses recovery data to extend the effective duration of pumping. The method is straightforward to implement and applicable for simple or complex hydrogeologic settings. The only assumption invoked is that the response remains linear such that the principle of superposition can be applied. No other assumptions about the properties of the aquifer are required. The method can greatly increase the value of pumping tests by extending the effective duration of the tests for as long as significant residual drawdowns are observed. 相似文献
82.
Sulfate (S and O) isotopes used in conjunction with sulfate concentration provide a tracer for ground water contributions to base flow. They are particularly useful in areas where rock sources of contrasting S isotope character are juxtaposed, where water chemistry or H and O isotopes fail to distinguish water sources, and in arid areas where rain water contributions to base flow are minimal. Sonoita Creek basin in southern Arizona, where evaporite and igneous sources of sulfur are commonly juxtaposed, serves as an example. Base flow in Sonoita Creek is a mixture of three ground water sources: A, basin ground water with sulfate resembling that from Permian evaporite; B, ground water from the Patagonia Mountains; and C, ground water associated with Temporal Gulch. B and C contain sulfate like that of acid rock drainage in the region but differ in sulfate content. Source A contributes 50% to 70%, with the remainder equally divided between B and C during the base flow seasons. The proportion of B generally increases downstream. The proportion of A is greatest under drought conditions. 相似文献
83.
Parsons ML Walsh WJ Settlemier CJ White DJ Ballauer JM Ayotte PM Osada KM Carman B 《Marine pollution bulletin》2008,56(6):1138-1149
Four coral-dominated coastal sites within two embayments (Kealakekua Bay and Honokōhau Bay) on the lee of the island of Hawai'i were studied to assess evidence of anthropogenic impacts in these relatively pristine locales. Nutrient-loading parameters were analyzed in relation to benthic composition data. Statistically, there were significant positive relationships between nitrate+nitrite, silicate, and ammonium with the abundance of macroalgae, coralline algae, and dead coral, and between delta(15)N and dead coral abundance. The north outside site of Kealakekua Bay and the south outside site of Honokōhau Bay appear to be most impacted by nutrient-loading factors in each bay, respectively. Comparisons with past nutrient data indicate that nutrient inputs have increased to the two bays, and that early impacts of these increased loadings are evident. It is predicted that at current nutrient-loading rates, the north sites of Kealakekua Bay and the south sites of Honokōhau Bay will exhibit evidence of further degradation in future years. 相似文献
84.
Experimentally, a feasibility study for adsorption and catalytic pyrolysis of spill oils on Cu/ZSM-5 for recycling of light oils has been conducted in the present work. The adsorption and pyrolysis of model compounds such as heptane, toluene, and diesel (to stimulate the spill oils) on Cu/ZSM-5 have been investigated on a continuous fixed-bed reactor. By component fitted X-ray absorption near edge structural (XANES) spectroscopy, catalytic active species such as metallic copper (Cu) (77-84%) and Cu(2)O (6-7%) are found in the channels of ZSM-5 during pyrolysis of heptane or toluene. Pyrolysis of diesel effected by Cu/ZSM-5 yields gas (C(1)-C(5)) (32%) and light oil (68%) that can be used as auxiliary fuels. 相似文献
85.
Taylor CJ 《Marine pollution bulletin》2006,53(1-4):30-48
The use of low levels of oxidants as antifouling agents in coastal and estuarine power station cooling water circuits can give rise to concerns over the likely production of chlorination byproducts (CBPs) including organohalogens, of largely cryptic identity, loading and impact. In order to review the current understanding of the degree of impact involved this paper describes a recent collaborative programme of work on CBPs within the wider context of a number of allied studies on power station cooling water entrainment and discharge effects. Bromoform was the single most important CBP found in coastal power station effluents. Although bromoform was found to accumulate in the liver of the sea bass Dicentrarchus labrax (L.) continuously exposed to a chlorinated effluent stream, no otherwise untoward impact on continuously exposed individuals was discerned. Populations of the common blue mussel Mytilus edulis L., likewise exposed, exhibited two responses: a high degree of genoplasticity and the evolution of stress proteins--although both may have been due to thermal rather than toxic stress. Experiments on plankton that simulated the conditions of entrainment within cooling water systems isolated the influence of oxidant usage, with mortality varying between taxa and life stage. The results suggest a very limited impact of oxidant use and the associated CBPs on receiving waters both in terms of plume toxicity or any more widespread ecotoxicological influence. Instead, it is in combination with applied temperature (DeltaT), pressure and the other stressors involved in entrainment within the power station cooling water circuits themselves that an impact is most marked. 相似文献
86.
Contaminant plume classification system based on mass discharge 总被引：1，自引：0，他引：1
Estimation of mass discharge has become an increasingly valuable analysis technique at sites with contaminated groundwater plumes. We propose a simple plume magnitude classification system based on mass discharge comprised of 10 separate magnitude categories, such as a "Mag 7 plume." This system can be a useful tool for scientists, engineers, regulators, and stakeholders to better communicate site conceptual models, prioritize sites, evaluate plumes both spatially and temporally, and determine potential impacts. 相似文献
87.
本文介绍两种适用于远震记录的方法，来表征地震事件的时间进程。叠加由大的区域台阵记到的短周期信号可获得震源高频辐射的稳定估计；而对经验格林函进行反褶积则可获得适用于分析破裂复杂和破裂时空间尺度的可靠的宽带震源时间函数。 相似文献
88.
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