Theses and Dissertations

Title: Dipyridylium residues in an aquatic environment

Name: Beasley, Philip Gene

Degree: PhD

Chair: Dr. John M. Lawrence


University: Auburn

Location: Auburn, Alabama

Date: 1967

Pages: 78

Keywords: Dipyridylium,Residue,Aquatic Environment.


The toxicity of diquat or paraquat to channel catfish eggs stocked in plastic pools was investigated. There was no difference between the number of eggs which hatched in untreated pools and in pools treated with 1 ppm diquat or paraquat (cation). Radioassay of blood samples withdrawn from goldfish which were previously injected intraperitoneally with 19.3 microcuries of C14-ethylene labeled diquat and allowed to swim in fresh water for 24 and 48 hours, respectively, and from goldfish which were placed in a 4 ppm diquat solution for 24 and 72 hours, respectively, demonstrated that diquat (or labeled atom) was transported in the plasma and was not bound to blood cells. Autoradiographs of electrochromatograms and sodium dithionite reduction of spots on electrochromatograms confirmed the presence of diquat in the plasma. Radioassay of organs and tissues of these goldfish showed that radioactivity was distributed throughout the organs and tissues of the fish. Maximum radioactivity was detected in the digestive tracts of injected and bathed fish. Radioassay of tissues and organs of small goldfish, which were allowed to swim in fresh-water following a 3-day exposure period in a 4 ppm C14-labeled diquat solution, showed no detectable radioactivity at the end of 10 days except in the digestive tract.Residue analyses were made on tissues and organs of channel catfish collected from plastic pools which had received single applications of 1 ppm paraquat or diquat and two applications of 1 ppm diquat or paraquat applied at 3-month intervals. No diquat or paraquat residue was detected in the organs or tissues of these fish which were collected 5 months after a single application or 2 months after the second treatment. Fish from pools treated or retreated with diquat contained 0 to a trace of diquat in the contents of the digestive tract. Fish from pools treated or retreated with paraquat contained in excess of 2 ppm and 6.9 ppm paraquat, respectively, in the digestive tract contents. No detectable diquat or paraquat was found in water samples from these pools. The average concentration of diquat or paraquat in soil samples collected from these pools 9 months after the single application was 18.6 and 19.4 ppm, respectively. Five months after the repeat application, the average concentration of diquat or paraquat in the soil was 32.3 and 70.7 ppm, respectively. A trace to 1.7 ppm diquat and 1.2 to 7.9 ppm paraquat was found in soil samples collected in 1966 from 13 plastic pools treated in 1962 at the rate of 0.3 lb per acre diquat or paraquat. Soil samples collected in 1966 from 33 plastic pools treated with diquat and/or paraquat from 1962 to 1964 contained 21.0 to 44.9 ppm paraquat. The presence of diquat in these soil samples was not confirmed.

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