• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 498
  • 97
  • 97
  • 31
  • 31
  • 31
  • 31
  • 31
  • 31
  • 13
  • 12
  • 9
  • 9
  • 5
  • 5
  • Tagged with
  • 1255
  • 1255
  • 318
  • 247
  • 241
  • 238
  • 230
  • 198
  • 193
  • 172
  • 165
  • 149
  • 95
  • 94
  • 90
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

Sublethal Effects of Nitrite and Selenate on Two Species of Freshwater Fsh

Watenpaugh, Donald E. (Donald Edward) 08 1900 (has links)
Physiological and behavioral effects of exposure of fathead minnows (Pimephales promelas) and channel catfish (Ictalurus punctatus) to selenate-selenium (Se) and nitrite were investigated.
332

Mass Loadings of Selected Water Quality Parameters for the State of Florida

Miller, Charles D. 01 January 1976 (has links) (PDF)
The mass loadings of pollutants common in surface waters result from the discharges of many different sources. In the last few years it has been noted that nonpoint sources contribute more pollutants than point sources. This is because in many cases the point source discharges have been, by law, reduced drastically. In the State of Florida many water quality parameters were examined to estimate the mass loadings in streams related to, drainage area, average flow, land use, soil type and management practices. A total of sixteen streams were examined. The information was first calculated for mass loadings as a function of stream flow. Next the slopes and intercepts were related to drainage area. Both steps were accomplished using bi-variate regression analysis. The final results show a relationship of Total Organic Carbon, Orthophosphate, Total Phosphate and Nitrate to drainage area and stream flow. However, the final results of this study when related to another study in Florida showed different mass loading rates for TOC and TP. The differences were attributed to background levels of pollutants, local geology, hydrologic variability and management practices.
333

Stormwater Infiltration thru Sewer Lines in Brevard County, Florida

Stubbe, Robert Earl 01 January 1976 (has links) (PDF)
This is a broad study of stormwater infiltration and inflow effects on two sewer systems with an equivalent size for comparison in Brevard County, Florida. The systems are Rockledge, which is located on the highest ground in the area, and Cocoa Beach, which is located down in the local water table. Rainfall data, sewage flow, quality, and flow rates were collected from the Brevard Public Health Department, Cocoa Beach and Rockledge sewage Plants, weather stations, and the Cocoa Water plant. The data indicated minimum, or no infiltration thru the Rockledge wastewater collection system. However, infiltration thru the Cocoa Beach system was estimated to be 3,800 gpd/in. dia./mi. Also, the sewage collected thru Rockledge and Cocoa Beach plants averaged about 50% and 160% of the water consumed respectively.
334

Effects of water pollution control costs on mining economics : the case of the base metal sector in Canada

Papanicolaou, Nicos A. January 1980 (has links)
No description available.
335

Treatment of overflows from combined sewers

Colston, Newton V. 08 July 2010 (has links)
Introduction: Automation and the danger of over productivity have created unprecedented amounts of leisure time in the United States. We are now in the process of finding that major potential recreational areas have been seriously polluted by the by-products of the same automation and productivity which have created our leisure time. Increasing urbanization has been accompanied by progressively more stringent demands on water quality and quantity while steadily impairing the same parameters . One of the major sources of water quality impairment due to concentrated urban growth is combined sewer overflow... / Ph. D.
336

Statistical sampling policy with applications to water pollution

Overbey, John William January 1969 (has links)
This thesis presents a sampling policy which offers the experimenter some statistical grounds upon which to base a decision as to when subsequent stream samples should be taken so as to detect a polluted condition. For any proposed sampling policy, the experimenter, without actually sampling, can evaluate the frequency of required sampling, can obtain a "feel" for how quickly changes in stream conditions can be detected, and can make comparisons with capabilities offered by other proposed sampling policies. Regression analysis of field data was conducted to explore possible relationships between stream dissolved oxygen content and physical factors. The resulting models were incorporated into the above mentioned sampling policy. / Master of Science
337

A MATHEMATICAL MODEL OF PRIMARY PRODUCTIVITY AND LIMNOLOGICAL PATTERNS IN LAKE MEAD

Everett, Lorne G. 09 1900 (has links)
The temporal and spatial changes in chemical and biological properties of Lake Mead have been investigated, thereby indicating the sources of water pollution and the time of highest pollution potential. Planktonic organisms have been shown to indicate the presence of water problems. Macro- and micro-nutrient analyses have shown that primary productivity is not inhibited by limiting concentrations. A mathematical model has been developed, tested with one set of independent data, and shown worthy of management utility. Although the model works very well for the Lake Mead area, the physical reality of the Multiple Linear Regression equation should be tested on independent data.
338

Transboundary water pollution: a legal perspective

Ng, Kwok-keung, Stephen, 吳國強 January 2002 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
339

The effects of activated carbon adsorption and ozonation on trihalomethane speciation

Tan, Lo, 1963- January 1989 (has links)
Two surface water sources in the southwestern United States, Colorado River Water (CRW) and California State Project Water (SPW), were studied in bench-scale experiments examining two Trihalomethane (THM) precursor removal processes, activated carbon adsorption and ozone oxidation. Both source water contained bromide (Br-) ion leading to brominated THMs upon chlorination. Activated carbon removed THM precursors, as measured by dissolved organic carbon (DOC), while having little effect on bromide. The net result was an increase in the ratio of Br-/DOC and an increase in the relative abundance of brominated THMs. Ozone oxidized higher molecular weight precursor molecules into lower molecular weight by-products which were less reactive with chlorine. Moreover, ozonation transformed Br- to hypobromous acid (an "in-situ" oxidant), leading to an increase in the percentage of brominated THMs.
340

Effects of Sublethal Copper Exposure on Escape Behavior and Growth of Rana pipiens Tadpoles

Redick, Melinda 05 1900 (has links)
This research is designed to test how sublethal exposure to copper affects tadpole predator-escape behavior and how quickly tadpoles recover. After exposure, tadpoles were separated. Escape behavior was recorded for two-thirds of exposed tadpoles while one-third of the exposed population was measured weekly to determine growth and recovery. Control tadpoles were consumed within 15 minutes whereas those exposed to higher concentrations were consumed at a slower rate, which does not support the hypotheses. Although the rate of predation was lower, tadpoles exposed to higher Cu concentrations were on average, 1.47 cm in total body length. Those exposed to 0.93 mg/L averaged 0.86 cm. After being placed into clean water, treatment tadpoles recovered after 20 days.

Page generated in 0.0762 seconds