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T.D. Bills

Publications and source records attributed to T.D. Bills.

32 records · Page 2Linked to original sources
USGS1985

Effects of contaminants on toxicity of the lampricides TFM and Bayer 73 to three species of fish

Waters in the Great Lakes basin contain more than 400 contaminant chemicals that potentially affect fishery resources, commerce, and human inhabitants. We determined in the laboratory the effects of selected contaminants on the toxicity of the widely used lampricides TFM (3-trifluoromethyl-4-nitrophenol) and Bayer 73 (2′,5-dichloro-4′-nitrosalicylanilide) to three species of fish—rainbow trout ( Salmo gairdneri ), white sucker ( Catostomus commersoni ), and fathead minnow ( Pimephales promelas ). The fish were exposed to paired mixtures of lampricides and selected contaminants in standardized, acute static toxicity tests to determine the resulting type of response—less than additive, additive, or greater than additive (synergistic). As expected, the toxicities of combinations of lampricides with organic pesticides, metal, industrial or municipal pollutants, and tannic acid were mostly additive. However, the toxicity of a combination of TFM, Delnav, and malathion was synergistic, and extremely small quantities of each chemical became lethal when mixed. The concentration that produced 50% mortality was 1.64 mg/L for TFM alone but only 0.041 mg/L for TFM with the pesticides. Toxicities of the pesticides in the combination also increased commensurately. The triple combination of chemicals produced extraordinary synergism and effectively demonstrated the hazards that may result if certain chemical combinations occur in the aquatic environment. However, synergism is not the only kind of toxic action that produces hazards to aquatic organisms. All three types of toxic action are of concern because toxic units produced by contaminant chemicals add to the toxic units of applied management chemicals. Since the toxicity of the majority of chemical combinations is simply additive, this cumulative toxic action contributes more total units to aquatic environments than the extreme actions of less than additive and synergism. The toxicity of the lampricide TFM, as well as other management chemicals, is reinforced by the presence of any contaminant that contributes additional units of toxicity. Therefore, all types of cumulative toxic action should be of concern to people and agencies involved with protecting the environment.

Journal of Great Lakes Research↗
USGS1985

Toxicity of the lampricides 3-trifluoromethyl-4-nitrophenol (TFM) and 2',5-dichloro-4'-nitrosalicylanilide (Bayer 73) to eggs and nymphs of the mayfly (Hexagenia sp.)

Eggs and nymphs of mayflies (Hexagenia sp.) were exposed to the lampricides 3-trifluoromethyl-4- nitrophenol (TFM) and 2',5-dichloro-4'-nitrosalcylanilide (Bayer 73) and to a mixture of 98% TFM and 2% Bayer 73 (TFM-2B) to determine the sensitivity of various life stages to these compounds. Some eggs and newly hatched nymphs survived concentrations of TFM up to 10 mg/L; and nymphs of the other groups tested (7, 16, 23, and 27 mm long) died at concentrations of 5 mg/L or more. Eggs and nymphs were unaffected by Bayer 73 concentrations up to 0.4 mg/L, the highest concentrations tested.

Technical Report↗
USGS1981

Polychlorinated biphenyl (Aroclor (R) 1254) residues in rainbow trout: Effects on sensitivity to nine fishery chemicals

The influence of background polychlorinated biphenyl (PCB) residues in rainbow trout ( Salmo gairdneri ) on the susceptibility of the fish to nine chemicals routinely or occasionally used in fishery operations was evaluated. Rainbow trout fry were divided into three groups: one was exposed to 0.01 ppb and another to 0.1 ppb of the PCB Aroclor (R) 1254; the third (control) group was unexposed. After 30 days of exposure, whole body residues were 0.28 and 2.31 ppm for fish exposed to 0.01 and 0.1 ppb, respectively; control fish had residue concentrations of 0.04 ppm. Acute toxicity tests showed that both groups of exposed fish were more sensitive to rotenone and 2,4-D. Exposure did not significantly affect sensitivity to 2-[digeranylamino]-ethanol (GD-174), 3-trifluoromethyl-4-nitrophenol (TFM), nifurpirinol (Furanace), tricaine methanesulfonate (MS-222), or copper sulfate. Fishery managers should be aware that sensitivity of fish to control chemicals may be altered by the presence of contaminants in the water or residues of contaminants in the fish.

North American Journal of Fisheries Management↗