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V. K. Dawson

Publications and source records attributed to V. K. Dawson.

At least 37 records · Page 2Linked to original sources
USGS1987

Elimination of super(14)C-bisazir residues in adult sea lamprey (Petromyzon marinus)

Bisazir (P.P-bis(1-aziridinyl)-N-methylphosphinothioic amide), a chemosterilant, was administered to sea lampreys (Petromyzon marinus ) by intraperitoneal injection of 100 mg/kg or by immersion for 2 h in a 100- mg/L aqueous solution of the chemical. Whole body analysis of the injected lampreys showed that total residue concentrations decreased to 4.65 in males and 10.07 in females during the first day after injection, and to 1.46 in males and 3.74 in females after 10 days of withdrawal. Lampreys exposed by bath immersion contained residues of about 25 mu g/g of tissue immediately after exposure. The concentration ( mu g/g) decreased to 1.02 in males and 2.11 in females after 1 day of withdrawal and to 0.51 in males and 0.85 in females after 10 days.

Technical Report↗
USGS1986

Computer program calculation of gas supersaturation in water

A short computer program, written in BASIC for the Apple IIe or IBM PC computer, efficiently performs all the calculations required to determine gas pressure and percent saturation values for water. Input for the program is limited to empirical determinations of barometric pressure, water temperature, differential dissolved gas pressures, dissolved oxygen, and salinity. An optional routine is included for obtaining a printed report of input data and results. The program can be easily modified to run on most other microcomputers that use BASIC programming language.

Progressive Fish-Culturist↗
USGS1986

An integrated system for treating nitrogen supersaturated water

Groundwater is commonly supersaturated with nitrogen and must be treated before it is used for culturing fish–especially sensitive species such as lake trout (Salvelinus namaycush) and Atlantic salmon (Salmo salar). We treated water with an integrated system that passed water through a packed column aerator, then through a vacuum degasser, and finally through another packed column aerator (installed as a backup system). Packed‐column aeration prior to vacuum degassing provided increased efficiency because only a small amount of vacuum was required to remove the remaining excess nitrogen, and oxygen levels were not affected by the vacuum degasser. In well water passed through packed columns, nitrogen gas was reduced from 131 to 105% of saturation and oxygen was increased from 23 to 86% of saturation. With a vacuum pressure of 3 in Hg, the degasser further reduced the nitrogen gas from 105 to 99% of saturation, and oxygen saturation remained near 86%. The integrated system provided water in which all gases were near saturation. No effects of gas supersaturation have been observed among the 18 species of cold‐water, coolwater, or warmwater fish that have been cultured in this water.

Progressive Fish-Culturist↗
USGS1986

Potential for nitrosamine formation in seven fishery chemicals

In recent years, nitrosamines have been reported as possible causes of cancer, mutations, or birth defects. Inasmuch as these compounds may be formed by the interaction of certain amines with nitrite in the aquatic environment, we evaluated seven fishery chemicals for their potential to form nitrosamines: the experimental fish toxicant digeranylethanolamine (GD‐174); the four therapeutants Terramycin, erythromycin, Hyamine 1622, and Hyamine 3500; and the two tracer dyes rhodamine B and rhodamine WT. The results indicate that the controlled use of the seven fishery chemicals in natural environments will not lead to the formation of nitrosamines.

Progressive Fish-Culturist↗
USGS1986

Persistence of rotenone in ponds at different temperatures

Two ponds were treated with liquid rotenone (5% rotenone), one with 3 mg/L at 24°C and the other with 2 mg/L at 0°C (concentrations of active rotenone were 0.15 and 0.10 mg/L, respectively). Water samples were collected and analyzed by high-performance liquid chromatography. The concentration of rotenone declined to 0.02 mg/L in 48 h in warm water and in 11 d in cold water. The half-life of rotenone was calculated at 13.9 h in warm water and 83.9 h in cold water.

North American Journal of Fisheries Management↗
USGS1986

Loss of lampricides by adsorption on bottom sediments

Problems have been encountered in maintaining effective concentrations of the lampricides 3-trifluoromethyl-4-nitrophenol (TFM) and 5,2a??-dichloro-4a??-nitrosalicylanilide (Bayer 73) during treatments of certain Great Lakes tributaries. Concentrations of Bayer 73 decreased by more than 80% in a portion of the Ford River, Michigan, during treatment in 1980. Adsorption of Bayer 73 on sediments was hypothesized as the primary mechanism of this excessive loss. Subsequent laboratory studies demonstrated that lampricides are adsorbed by silt-type sediments that are high in organic content, including those collected from the treated portion of the Ford River. Un-ionized lampricides (acidic solution) were more readily adsorbed than ionized forms (basic solution). Adsorption onto sediments was proportionally greater, and desorption proportionally less, for Bayer 73 than for TFM. When Ford River sediments were mixed with lampricide-free water, less than 10% of the adsorbed Bayer 73, but more than 60% of the TFM, was released. The extensive adsorption of the lampricides (especially Bayer 73) from solution by silt-type sediments explains much of the loss of effective concentrations in certain streams.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1983

Rapid method for measuring rotenone in water at piscicidal concentrations

A high‐performance liquid chromatography (HPLC) procedure that is rapid, specific, and sensitive (limit of detection <0.005 mg/liter) was developed for monitoring application and degradation rates of rotenone. For analysis, a water sample is buffered to pH 5 and injected through a Sep Pak(R) C 18 disposable cartridge. The cartridge adsorbs and retains the rotenone which then can be eluted quantitatively from the cartridge with a small volume of methanol. This step effectively concentrates the sample and provides sample cleanup. The methanol extract is analyzed directly by HPLC on an MCH 10 reverse‐phase column; methanol: Water (75:25, volume : Volume) is the mobile phase and flow rate is 1.5 ml/minute. The rotenone is detected by ultraviolet spectrophotometry at a wavelength of 295 nm.

Transactions of the American Fisheries Society↗
USGS1982

A rapid high-performance liquid-chromatographic method for simultaneously determining the concentrations of TFM and Bayer 73 in water during lampricide treatments

The high-performance liquid-chromatography (HPLC) procedure requires only minutes per sample, is specific, and is relatively sensitive (limit of detection < 0.005 mg/L for both chemicals). A combined buffer (pH 4) and internal standard (3-chlorodiphenylamine) reagent is added to the water sample, which is injected through a Sep Pak C 18 disposable cartridge. The cartridge adsorbs and retains both the lampricides and the internal standard. The quantitative elution of the three chemicals from the cartridge with a small volume of methanol effectively concentrates the sample and provides sample cleanup. The methanol extract is then analyzed directly by HPLC on an MCH 10 reverse phase column by using a methanol:0.01 mol/L acetate buffer (87:13, v:v) as the mobile phase at 2 mL/min and detected by ultraviolet spectrophotometry at 330 (or 254) nm. A microprocessor data system further facilitates the procedure by quantifying off-scale peaks and yielding results directly in units of concentration (mg/L).

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1979

Excretion of the lampricide Bayer 73 by rainbow trout

Urinary excretion of the 2-aminoethanol salt of 2′, 5-dichloro-4′-nitrosalicylanilide (Bayer 73) in rainbow trout ( Salmo gairdneri ) was measured after exposure of the trout to Bayer 73 and also after intraperitoneal (ip) injection of the lampricide. Fish exposed to 0.05 mg/litre of Bayer 73 for 12 h quickly began to excrete residues in the urine. The largest amount of Bayer 73 was excreted during the 12-h exposure, but the trout continued to excrete Bayer 73 beyond 60 h after exposure. After rainbow trout were given ip injections of 200 µ g of Bayer 73 in corn oil, they excreted up to 25 percent of the injected dose in the urine, and 20 percent was recovered in the bile at the end of the study. In both groups of fish most of the renal excretion of Bayer 73 was as the glucuronide conjugate. The exposure of rainbow trout to Bayer 73 at the doses studied had no effect on the urine output or on the renal excretion of sodium (Na + ), potassium (K + ), calcium (Ca 2+ ), magnesium (Mg 2+ ), and chloride (Cl - ).

Conference Paper↗
USGS1979

Ethyl-p-aminobenzoate (Benzocaine): efficacy as an anesthetic for five species of freshwater fish

Ethyl-p-aminobenzoate (benzocaine) was tested for its efficacy as an anesthetic for rainbow trout (Salmo gairdnerii, brown trout (Salmo truttas, northern pike (Esox lucius). carp (Cyprinus carpio), and largemouth bass (Mieropterus salmoidesi. Since benzocaine is not water soluble, it was applied with acetone as a carrier. Concentrations of 100 to 200 mg!l were required for large adult northern pike, compared with 50 to 100 mg/l for small fish. Rates of sedation and recovery were slower in cold water than in warm water. Water hardness had little influence on the activity of benzocaine. Fish were anesthetized faster and recovered more slowly in acid than in alkaline water. Benzocaine produced deep anesthesia, but concentrations that rendered the fish handleable within 5 min were generally not safe for exposures longer than 15 min. Concentrations of benzocaine efficacious for fish were not acutely toxic to eggs of coho salmon (Oncorhynchus kisutch), chinook salmon (Oncorhynchus tshauiytschas, rainbow trout, brown trout, or lake trout (Salvelinus namaycush). Benzocaine is not registered for fishery use and is neither more effective nor safer than the registered anesthetic, tricaine methanesulfonate (MS-222l.

Investigations in Fish Control↗
USGS1978

Rapid method for determining concentrations of Bayer 73 in water during lampricide treatments

Two simple, rapid, sensitive methods were developed for determining the concentration of the lampricide 2',5-dichloro-4'-nitrosalicylanilide (Bayer 73) in stream water. Bayer 73 was extracted from acidified water samples with chloroform and then hydrolyzed to 2-chloro-4-nitroaniline (CNA) with either acid or base. The CNA was diazotized with sodium nitrite, and an azo dye was formed with either N -( 1-naphthyl) ethylenediamine dihydrochloride (after acid hydrolysis) or 1-naphthol (after base hydrolysis). There was no interference from the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) in either method. Standard curves were prepared with untreated water to compensate for interfering substances that occurred naturally in some streams. The methods were sensitive to about 0.005 mg/L (ppm). Time required for analysis of a sample ranged from 25 min to 1 h.

Journal of the Fisheries Research Board of Canada↗