Environmental Chemistry Commons^™

The Combined Effect Of Cu And Zn On Selenastrum Capricornutum, Helmer Colonia-Roque

Dissertations and Theses

It has been demonstrated that the toxicity of heavy metals depends on their chemical speciation and can be related to their free ion activities, rather than the total metal concentrations. The objective of this study was to determine the effect of combined free ions of zinc and copper on the toxicity to the green alga Selenastrum capricornutum. This alga was grown in a defined medium, under controlled laboratory conditions, with a varying range of zinc and copper concentrations. The growth rate of the alga was inhibited at pZn = 5.93 or at pCu = 7.24. The results suggest that …

Use Of Hydroelectric Dams To Control Evaporation And Salinity In The Colorado River System, Larry J. Paulson

Publications (WR)

The main stem reservoirs on the Colorado River comprise one of the largest and most heavily used freshwater bodies in the nation. These reservoirs (Lake Powell, Lake Mead, Lake Mohave and Lake Havasu) can store up to 53,590,400 acre-feet of water at their maximum capacities. Nonetheless, local water shortages still exist in some areas of the Colorado River Basin. There is also concern that salt concentrations are approaching levels that could severely affect municipal and agricultural uses. Water shortages will become even more acute as demands for water increase with continued urban and agricultural development in the basin. Water conservation …

Diagenesis Of Organic Matter In Las Vegas Bay And Bonelli Bay, Lake Mead, James W. Murray, Carolyn J. Jones, Kathy Kuivila, Jeff Sawlan

Publications (WR)

The interstitial water chemistry of the sediments of Las Vegas Bay and Bonelli Bay in Lake Mead has been studied as part of a comprehensive water quality study of those locations. Pore water and solid phase analyses were completed from four stations in Las Vegas Bay and two stations in Bonelli Bay. At both locations the pore water compositions and organic matter diagenesis in the sediments are dominated by sulfate reduction. This major role of sulfate reduction is unusual for lake sediments and reflects the fact that SO₄ is the major anion in the lake water. In addition, gypsum …

Influence Of Las Vegas Wash Density Current On Nutrient Availability And Phytoplankton Growth In Lake Mead, John R. Baker, Larry J. Paulson

Publications (WR)

Density currents are commonly formed in reservoirs because of temperature or salinity induced density differences between inflowing and receiving waters. Anderson and Pritchard (1951) were among the first to demonstrate this in their investigations of density currents in Lake Mead. They found that the Colorado River formed an underflow in Lake Mead during the winter, an overflow in the spring and an interflow in the summer and fall. Wunderlich and Elder (1973) have since described the hydromechanics of these types of flow patterns, and density currents have been reported for several other large reservoirs (Carmack et al. 1979, Johnson and …

A Review Of The Limnology Of And Water Quality Standards For Lake Mead, Charles R. Goldman

Publications (WR)

1. The waters of Las Vegas Bay, a heavily utilized recreational resource, receive discharges from a variety of municipal and industrial waste sources. The U.S. Environmental Protection Agency has determined, on the basis of numerous studies, that the present water quality violates state and federal standards and constitutes a public nuisance. Consultants have advised the Sewage and Wastewater Advisory Committee that rapid abatement of the alleged pollution conditions can be achieved by an advanced wastewater treatment (AWT) plant.

2. The major problems in Las Vegas Bay are an objectionable water color, excessive turbidity, noxious odors, and oxygen depletion in certain …

Bulletin No 3993 - The Control Of Saffron Thistle, G. A. Pearce

Bulletins - 3000 - 3999

Saffron thistle is a primary noxious weed and is widespread throughout the drier parts of Western Australia. When growing in pasture its prickly growth habit discourages animals from grazing amongst it so that its presence results in the loss of feed. In crops it reduces yield and results in dockage when seed is found in harvested grain.

A Systems Study Of Oil Pollution Abatement And Control For Portland Inner And Outer Harbor, Casco Bay, Maine, Arthur D. Little, Inc.

Maine Collection

A Systems Study of Oil Pollution Abatement and Control for Portland Inner and Outer Harbor, Casco Bay, Maine

to State of Maine, Department of Environmental Protection, State House Augusta, Maine 04330

Appropriation Number 4320-4001

by Arthur D. Little, Incorporated, 20 Acorn Park, Cambridge, Massachusetts 02140 (March 15, 1976).

Contents: Executive Summary / 1. Introduction / 2. Identification of Vulnerable Resources / 3. Potential Oil Spill Locations / 4. Oil Spill Movement / 5. Containment and Disposal Systems / 6. Oil Monitoring Systems / 7. Marine Navigation In Portland Inner and Outer Harbors / Appendices

Final Report On Interrelationships Between Chemical, Physical And Biological Conditions Of The Waters Of Las Vegas Bay Of Lake Mead, James E. Deacon, Richard W. Tew

Publications (WR)

This program was a status study of the interaction between Las Vegas Wash, an enriched stream, and Las Vegas Bay, a wedge shaped arm of one of the world's deeper reservoirs. The program centered primarily on identification and counting of planktonic algae from several points in Las Vegas Bay. Additional work on nutrient enrichment of water samples was conducted to aid in interpretation of algal distribution related to nutrient input. Examination of a variety of physical, chemical, and biological parameters, both at many surface points in the bay, as well as in vertical profile, was also accomplished and further aided …

Micronutrients And Biological Patterns In Lake Mead, Hasan K. Qashu, Lorne G. Everett, J. S. Carlson, Bureau Of Reclamation

Publications (WR)

Progressive increases in concentration of dissolved solids in the Colorado River water from Lake Powell to Imperial Dam seem to alter plankton dynamics and biological productivity of the river. Also, changes in biological productivity and micronutrients concentrations occur within the same reservoir. Development of a digital simulation model to predict micronutrients concentrations and biological productivity is necessary for diagnosing changes in plankton population and effluent-carrying capacity of the system. The objectives of the study are: (1) to determine trace metal balance at different locations in Lake Mead, (2) to measure biological productivity and conduct plankton population counts at each sampling …

The Effects Of Herbicides On Three Soil Inhabiting Blue Green Algal Species, Lee C. Darlington

All Master's Theses

The object of this study was to examine the effects of varying concentrations of 2, 4-D, Dalapon, and Tordon on the growth of several nitrogen-fixing blue-green algal species obtained from soil samples and grown under culture conditions in the laboratory.

Chemical Firebreaks, Geoffrey A. Pearce

Journal of the Department of Agriculture, Western Australia, Series 4

MANY public bodies are making regular use of herbicides to create firebreaks. In Western Australia more than $200,000 is being spent on chemicals each year to protect property from fire.

In many situations where the buildings and property are of great value, the cost of the chemical becomes insignificant.

Biological Studies Of Selected Reaches And Tributaries Of The Colorado River, Nelson Thomas, Federal Water Pollution Control Administration

Publications (WR)

This report fulfills the request of the Colorado River Basin Project, Denver, Colorado, to determine the effects of municipal and industrial wastes on the aquatic life in selected waters of the Colorado River Basin. These studies were conducted with the assistance of personnel from the Colorado River Basin Project.

Development, Verification, And Use Of Methods To Model Chemical And Thermal Processes Lakes Mead And Powell, Bureau Of Reclamation

Publications (WR)

PURPOSE The purpose of the proposed research is to quantify the effects that Lakes Mead and Powell have on the salinity in the Colorado River system, and to evaluate changes that cap be made to the operating system of the reservoirs (within legal/institutional constraints) to enhance salt precipitation and/or minimize evaporation within the reservoirs. The effect of any changes (i.e., selective withdrawal uses, pumped storage, etc.) on reservoir evaporation could also be evaluated with a goal of minimizing evaporation. This will be accomplished through the development of a mathematical model of the reservoirs as described below. BACKGROUND Two major problems …

Water Chemistry Survey Of Boulder Basin, Lake Mead, P. R. Tramutt, Bureau Of Reclamation

Publications (WR)

The survey results indicate that the impoundment of water behind Hoover Dam has not adversely affected the dissolved oxygen (DO) content and that water quality and DO content were uniform regardless of depth. The study made in April-May 1964 will provide water quality data of Lake Mead prior to releases from Lake Powell as a basis for evaluating Lake Powell's effect on water quality and limnology of Lake Mead. The performance of a DO analyzer was tested and found unsatisfactory at depths below 150 ft. Parameters tested by standard chemical analyses of water samples in the Denver Laboratory and by …

Cobalt : Its Use To Control Wasting Disease, Laurence C. Snook

Journal of the Department of Agriculture, Western Australia, Series 4

FOR many years it was assumed that in Western Australia cobalt deficient areas were restricted to a coastal fringe which rarely extended more than 20 miles inland.

This has proved a costly false assumption. During recent years cobalt deficiency has been diagnosed over extensive areas of inland country.

Weed Research. 7. Weed Control Around The Yard, Geoffrey A. Pearce

Journal of the Department of Agriculture, Western Australia, Series 4

MANY farmers and city householders have weed problems around houses and sheds which can be readily overcome by treatment with appropriate herbicides.

The risk from fire through weeds and unslightly growth can easily be removed and an area free of any plant growth can be maintained with little effort for a considerable period.

The Teaching Of Science, Sherwin Maeser

Faculty Honor Lectures

Like to teach! Whether with the expectant, half-frightened freshman, the senior, worried about his preparation now that . he must get out and meet competition, or the graduate student interested in new discoveries, I like to work with all of them.

I have been teaching a long time now. As has always been the case when one generation is thinking of turning over its work to the next, I am glad to have the opportunity to talk about some of the things that I consider important in this job of teaching.

The most varied and the most acute problems of …