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941.
942.
ION‐SELECTIVE ELECTRODES IN ANALYTICAL CHEMISTRY, Vol. 2 by H. Freiser (ed.), Plenum Press, New York, 1980. CARCINOGENESIS AND MUTAGENESIS by Myron A. Mehlman, Morris F. Cranmer and Raymond E. Shapiro, from the Journal of Environmental Pathology and Toxicology (Official Organ of the American College of Toxicology), 388 pages and 135 tables and figures, 1977, linen, format 261 × 178 mm, ISBN 0–930376–02–1, printed by Pathotox Publishers, Inc., Park Forest South, Illinois 60466, $23.00. 相似文献
943.
Kinetic (batch) sorption and desorption experiments for some organochlorine insecticides in silt‐water suspensions are described. The effect of possible experimental artifacts on the results is examined. The influence of the silt/water ratio on the linear sorption coefficient and on the “nonextractable”; solute fraction is determined. The sorption process is described in terms of some kinetic models. 相似文献
944.
Jamie W. Baxter John D. Eyles Susan J. Elliott 《Journal of Environmental Planning and Management》1999,42(4):501-525
This paper contributes to the noxious facilities siting literature by exploring some implications of adhering to some recommended principles and practices for competent siting. Through a qualitative case study of a landfill siting process in Peel (Ontario, Canada) three principles are critically assessed: trust; equity; and community participation. While laudable notions in principle, in practice they can impact each other in important ways which can (potentially) undermine the siting process. These impacts result mainly from the failure to achieve meaningful goals associated with one principle (e.g. community participation) which can exacerbate problems achieving goals associated with other principles (e.g. trust). The resulting discord can be further aggravated by the snowballing of adverse effects over time. In particular, practices for achieving trust and equity were adversely linked, as were the relationships between spatial equity and procedural equity and interregional and intraregional equity. These adverse synergisms were linked together with ineffective community participation which brought the process to a halt. Siting inertia (a process momentum difficult to redirect) and an inflexible siting context contributed to these conflicts. Implications for siting and further research are discussed. 相似文献
945.
Substantial amounts of NO3 from agricultural crop production systems on poorly drained soils can be transported to surface water via subsurface drainage. A field study was conducted from the fall of 1993 through 2000 on a tile-drained Canisteo clay loam soil (fine-loamy, mixed, superactive, calcareous, mesic Typic Endoaquoll) to determine the influence of fall vs. spring application of N and nitrapyrin [NP; 2-chloro-6-(trichloromethyl) pyridine] on NO3 losses from a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. Four anhydrous ammonia treatments (fall N, fall N + NP, spring preplant N, and spring N + NP) were replicated four times and applied at 135 kg N ha(-1) for corn on individual drainage plots. Drainage occurred in all seven years. Seventy-one percent of the annual drainage and 75% of the annual NO3 loss occurred in April, May, and June. Fifty-four percent of the NO3 lost in the drainage occurred during the corn phase and 46% during the soybean phase. Annual flow-weighted NO3-N concentrations for the fall, fall + NP, spring, and spring + NP treatments averaged 14.3, 11.5, 10.7, and 11.3 mg L(-1) during the corn phase but annual NO3-N concentrations were still > or =10 mg L(-1) in three of six years for the spring preplant treatment. Averaged across the six rotation cycles, flow-normalized NO3-N losses ranked in the order: fall N > spring N + NP > fall N + NP > spring N. Under these conditions, NO3 losses in subsurface drainage from a corn-soybean rotation can be reduced 14% by spring N and 10% by late fall N + NP compared with fall-applied N. Nitrate losses were not appreciably reduced by adding NP to spring preplant N. 相似文献
946.
Steven W. Effler Rakesh K. Gelda Mary Gail Perkins David M. O'Donnell 《Journal of the American Water Resources Association》2005,41(4):971-984
The development, testing, and application of a probabilistic model framework for the light attenuation coefficient for downwelling irradiance (Kd) and Secchi disc transparency (SD) that resolves the effects of several light attenuating constituents, including phytoplankton and nonliving particles (tripton), is documented. The model is consistent with optical theory, partitioning the magnitudes of the light attenuating processes of absorption and scattering according to the contributions of attenuating constituents as simple summations. The probabilistic framework accommodates variations in the character and concentrations of these constituents and ambient conditions during measurements, and recognizes a linear relationship between the magnitudes of absorption and scattering by tripton. The model is tested and applied for a 21 km reach of the Seneca River, New York, that features optical gradients caused by an intervening hypereutrophic lake and dam, and a severe infestation of the exotic zebra mussel. The model is applied to resolve the roles of phytoplankton and tripton in regulating measured longitudinal patterns of SD along the study reach of the river and increases in SD since the zebra mussel invasion, and to predict decreases in Kd since the invasion. 相似文献
947.
W. A. White L. F. Tischler T. A. Austin 《Journal of the American Water Resources Association》1972,8(3):483-494
ABSTRACT A methodology for predicting the spatial and temporal levels of conservative water quality constituents within a multibasin water resource system is presented. Dissolved solids, sulfates, and chlorides are the constituents used during this investigation; however, any other conservative ion or mineral can be incorporated into the simulation model. The methodology is tested on the proposed Texas Water System. The water quality model, QNET-I, utilizes monthly canal and river flows and reservoir storage levels calculated by the Texas Water Development Board's systems simulation model. Discharge-concentration relationships are developed for each source of water in the system, including significant waste-water discharges. Reservoirs in the system are assumed to be completely mixed with respect to conservative constituents. A mass balance analysis is performed for each node and each month during the simulation period. The output from the water quality simulation is a table of the concentrations of the conservative water quality constituents at each demand point in the system and in each reservoir and canal for every month the system is in operation. The desired quality of the water at the demand locations is used to determine the economic utility of transporting and mixing water from various sources. 相似文献
948.
/ Land use/land cover classifications for 1973 and 1991, derived from the interpretation of satellite imagery, are quantified on the basis of biophysical land units in a study area in southeastern Australia. Nutrient export potentials are estimated for each land unit based on their composition of land use/land cover classes. Spatial and temporal comparisons are made of the land units based on the calculated pollution hazard indicators to provide an insight into changes in the state of the environment and the regional significance of land use changes. For example, one ecosystem, unique to the study, showed a large increase in pollution hazard over the study period as a manifestation of an 11-fold rise in cleared area and an expansion of cropping activities. The benefits to environmental management in general are discussed.KEY WORDS: Land cover change; Nutrient export; Environmental condition; Pollution hazard; Agricultural pollution; Nonpoint source pollution; Diffuse pollution; Environmental degradation 相似文献
949.
基于船舶自动识别系统(Automatic Identification System,AIS)数据表征船舶排放是目前船舶排放空间表征的主流方法,但AIS船舶轨迹点缺失会造成船舶排放量低估和船舶空间分布表征错误,进而影响船舶排放控制区的划分.为改进船舶排放空间表征,本研究以2013年广东省AIS船舶数据为例,采用基于时间和经纬度的三次样条方法对AIS船舶轨迹进行修复,结合动力法计算船舶排放,分析对比AIS轨迹修复前后船舶排放表征的差异,并利用空气质量模型和卫星观测评估AIS轨迹修复对船舶排放表征和广东沿海空气质量模拟的改进效果.结果表明:轨迹修复后广东省海域船舶轨迹点总数由4685773个增至5746664个,船舶NOx排放量增加了0.6%.对于轨迹点与排放缺失集中的粤东海域,轨迹修复后船舶轨迹点数增加了88%,NOx排放量在广东省船舶排放量的占比提升至22%,特别是在粤东重点修复海域NOx排放量增加了2.7倍.原始轨迹在广东省海域较为稀疏,在粤东海域有明显轨迹缺失;轨迹修复后广东省海域船舶轨迹更为密集,粤东海域船舶轨迹得... 相似文献
950.
E. Lamla F. Boschke G. Traving G. Pfotzer H. Wolter W. Walcher H. D. Dahmen H. J. Queisser W. W. Klingbeil K. Beyermann O. Müller R. R. Ernst D. Reinen H. Muth W. Becker G. Wunsch G. I. Distler L. Jaenicke H. G. v. Schnering H. Werner F. Reiff H. Schimassek W. Höll H. K. Vasil W. F. Angermeier W. Ruppel J. C. Eccles G. Spiteller H. Oettel W. Vogell P. Brosche K. J. Hsü H. -U. Schmincke 《Die Naturwissenschaften》1975,62(3):143-143