Environmental Monitoring Commons^™

Thermal Requirements To Protect Aquatic Life, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Water temperatures affect aquatic organisms in a number of ways, both directly and indirectly. Some of the latter effects are quite subtle. High temperatures can have direct lethal effects but sublethal levels operating over long periods can be just as harmful through delayed lethal effects and the production of nonlethal stresses which eventually result in changes in the population, reduced growth or reproduction, and the lowering of resistance to parasites, dis ease, and competitors. Temperature, in combination with certain other factors such as day length, influences re producing processes. High water temperatures may stimulate or retard migration, spawning, feeding, and …

Development Of Water Quality Criteria For Aquatic Life, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

It is now recognized that water pollution is an important problem, that it becomes more widespread and serious as population and industry expand, and that something must be done if aquatic life resource are to be saved and their productivity maintained. In the past there has been a great deal of uncertainty in approaching this situation and a general lack of understanding of the details and ramification of the overall problem. In the efforts for the abatement of pollution, only a few clearcut objectives have been established. Knowledge is lacking as to what the objectives should be. There is still …

Industrial Wastes: Bio-Assays For Control Of Industrial Effluents, Croswell Henderson, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Waste effluents from many industries are toxic to fish and other aquatic life. The control or treatment of these wastes for safe release into receiving waters presents a problem of consider able magnitude.

Much effort has been expended by some industries to solve this problem, primarily through chemical analysis for possible toxic components and then generally by a search of the literature to find out how toxic a particular component may be. Unfortunately, this approach has not been successful, nor can it be expected to be productive of satisfactory answers.

Stream Pollution- Aquatic Macro-Invertebrate Communities As Indicators Of Organic Pollution In Lytle Creek, Arden R. Gaufin, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Year-round field studies of the com position and ecology of stream communities associated with the purification of organic wastes in streams were initiated on Lytle Creek in October, 1949. This creek, which is located about 45 miles northeast of Cincinnati, Ohio, is a tributary of the Little Miami River. Its drainage basin comprises 27 sq. mi., a third of which is contained within the city limits of Wilmington, Ohio, a city of some 7,412 persons

Industrial Wastes, Charles E. Renn

United States Environmental Protection Agency: Publications

This paper presents a summary of experiences with a variety of cyanogenic wastes. The work has attempted to evaluate the interaction of waste bearing waters and the environment in terms of waste disposal design requirements. In this, the approach is somewhat more critical than that commonly taken by fisheries biologists, conservationists, and others who have been concerned with the "preventive" aspects of waste disposal.

The first phases of the work were designed to discover the tolerable limits of certain waste components to fresh water fish. This was undertaken in 1950; in the interval the composition of the wastes has been …

Stream Pollution, Ruth Patrick

United States Environmental Protection Agency: Publications

This paper discusses the various ways in which aquatic organisms may be of use in solving problems associated with waste disposal. Since many state and federal laws set forth that nothing may be discharged that is deleterious to aquatic life, the most expedient way to determine the effect of an effluent is to study the aquatic organisms themselves.

In every river that has not been adversely affected by pollution there is a great variety of aquatic life. These organisms do not represent a great mass of living things, but rather they are organized into an intricately balance systems, often referred …

It's Time To Take Stock

United States Environmental Protection Agency: Publications

Likening colleges and universities to the automobile industry may seem far-fetched, but is it? Each is engaged in fashioning and selling necessary products- one trained men, the other mechanical equipment. Both entered the post-war years with production at low ebb; unable to satisfy pent-up customer demands. Time and high-speed assembly lines have bridged the gap of gas buggy shortage. The impact of selective buying by a discriminating public is now real cause for concern among some of the motor moguls. Rumor has had it that schools teaching wildlife management are overproducing. We decided to gather facts and opinions at the …

Public Health Reports, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

Preliminary tests with DDT for the control of mosquitoes, forest insects, and agricultural pests demonstrated that it was toxic to a wide variety of animal life. Because there were indications that the new insecticide would be widely used, apprehension was expressed by some groups that its extensive or indiscriminate use would cause extensive harm to wildlife.

The desirability of carefully controlled use was early recognized by those in charge of extensive programs for the control of insects of public health importance. A joint statement of policy for the use of DDT issued early in 1945 (1) by the Army and …

Observations On The Nighttime Resting And Biting Habits Of Anopheline Mosquitoes In Ddt-Treated And-Untreated Buildings, Clarence M. Tarzwell, Frank W. Fisk

United States Environmental Protection Agency: Publications

Laboratory cage tests and controlled experiments in houses have clearly demonstrated that residual-spray deposits of DDT are lethal to mosquitoes for considerable periods. Although these tests valuable information on the durability of DDT residual deposits, they did not give information on the mortality of malaria mosquitoes naturally entering treated dwellings in search of a blood meal. In order to secure a lethal dose of DDT from residual deposits, mosquitoes must actually touch the material and be exposed to it for a considerable period. This period has been shown to vary (1), depending on the temperature, age of treatment, density and …

The Feeding Habits Of Gambusia Affinis Affinis, With Special Reference To The Malaria Mosquito, Anopheles Quadrimaculatus, A.D. Hess, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

The viviparous top minnow, Gambusia affinis affinis (Baird and Girard), has for many years been considered an important predator of the immature stages of mosquitoes. Various field workers have reported on the value of this species in controlling both anopheline and culicine mosquitoes, but few detailed studies have been made. Probably the most detailed of these has been that of Hildebrand (1925). His investigations were made during the summers of 1921-24 in the vicinity of Augusta, Ga., with the subspecies G. affinis holbrooki. Employing the common dipper method, he compared the densities of anopheline and culicine larvae and pupae in …

An Analysis Of Fishing In The Tva Impoundments During 1939, R. William Eschmeyer, Clarence M. Tarzwell

United States Environmental Protection Agency: Publications

An inventory of fishing on Norris, a storage reservoir, was begun in 1938. The following year it was extended to Wheeler, a run-of-the-river reservoir, and to the tailwater area below Wilson Dam. This inventory, therefore, covered each of the three general types of fish habitats created by the TVA dams. This discussion is a summary of the 1939 fishing data, together with recommendations for fish management based on the creel census information. The data collected totaled 34,270 usable fishing records, representing a catch of 98,495 fishes.