Theses and Dissertations


Title: The effects of turbidity and of light on the toxicity of two rotenone formulations to the fathead minnow

Name: Devi, Katragadda Vijaya Lakshmi

Degree: PhD

Chair: Dr. Homer S. Swingle and Dr. E.W. Shell

Resides: FAA Library

University: Auburn

Location: Auburn, Alabama

Date: 1962

Pages: 101

Keywords: Turbidity,Light,Toxicity,Rotenone,Fathead Minnow.

Abstract:

Laboratory experiments were conducted, in gallon jars at a constant temperature room held at approximately 70o F., to determine (1) the effect of plankton on the toxicity of Pro-Noxfish and Noxfish (2) the effect of clay suspensions on the toxicity of Pro-Noxfish and Noxfish, and (3) the effect of various wavelengths (3,200-7,000 Ao) of light on the toxicity of Noxfish. Pro-Noxfish contained 2.5 percent rotenone and 2.5 percent sulfoxide whereas Noxfish contained 5.0 percent rotenone. Fathead minnows, Pimephales promelas, were used as test animals. The duration of experiments was 24 hours.Pond water containing plankton, and pond water containing suspended clay colloids (muddy pond water) were obtained from farm ponds of Auburn, Alabama. In addition to the muddy pond water, the powdered forms of bentonite, kaolinite, and illite clay minerals were used to prepare clay suspensions. The plankton-water treatments were tested against tap water controls while the clay suspension treatments were tested against tap water or of mixtures of tap water and distilled water. Forty-watt fluorescent lamps emitting various wavelengths of light (black, blue, green, and red) were used as different sources of light. The effect of plankton on the toxicity of Pro-Noxfish and Noxfish was not consistent. In the majority of the plankton-water experiments plankton water did not reduce the toxicity of either rotenone formulation, and these results were associated with the occurrence of significantly smaller concentrations of oxygen in the plankton water than in the tap water. In one experiment in which the concentration of oxygen in plankton water and tap water were about the same, the plankton water reduced the toxicity of rotenone by 22.9 percent.Suspensions of bentonite, kaolinite, illite, and muddy pond water reduced the toxicity of the two rotenone formulations. As the concentration of bentonite increased from 32 to 200 p.p.m., the toxicity of Pro-Noxfish was decreased by 8 to 23.9 percent. The toxicity of Noxfish was also decreased by 18.0 to 48.3 percent as the concentration of bentonite increased from 30 to 220 p.p.m. Bentonite appeared to reduce the toxicity of Noxfish more than that of Pro-Noxfish.Kaolinite at 150 p.p.m. reduced the toxicity of Pro-Noxfish by 8.9 percent. As the concentration of kaolinite increased from 57 to 200 p.p.m., the reduction in toxicity of Noxfish increased by 12.4 to 23.9 percent. Kaolinite did not seem to be as efficient as bentonite in reducing the toxicity of the two rotenone formulations. Illite at 36 p.p.m. resulted in a 12.3 percent reduction in toxicity of Noxfish. The muddy pond water which contained 33 p.p.m. of inorganic matter and 17 p.p.m. of organic matter reduced the toxicity of Pro-Noxfish by 16.7 percent. The detoxification of Noxfish diluted with tap water was greater than the detoxification of undiluted Noxfish during a 12-hour exposure to black and red lights. Exposure to black light (3,200-4,500 Ao) for a 12-hour period caused a significant reduction in toxicity of Noxfish (23.4 percent), whereas blue (4,000-7,000 Ao), green (4,700-6,000 Ao), or red (5,900-7,000 Ao) lights did not cause a significant detoxification.Toxicity of Noxfish was reduced only an additional 4.1 percent when the distance between black light and the test solution was reduced from 13.8 inches to 5.8 inches in comparable exposure periods (12 hours). Exposure of Noxfish, diluted with tap water (pH=8.5) to various concentrations, to atmospheric air (aeration) reduced the toxicity 23.7 percent during a 12-hour period. Diluted Noxfish in conjunction with aeration and black light appeared to be more effective than aeration in conjunction with diluted Noxfish alone. Increase in total hardness from 11 to 39 p.p.m. did not significantly affect the toxicity of Noxfish. Exposure of diluted Noxfish to direct sunlight on March 4, 11 A.M. to 12 noon, resulted in 18.3 percent reduction in toxicity.

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