Theses and Dissertations


Title: The arsenic content of water, plankton, soil, and fish from ponds treated with sodium arsenite for weed control

Name: Dupree, Harry Kenneth

Degree: MS

Chair: Dr. John M. Lawrence

Resides: FAA Library

University: Auburn

Location: Auburn, Alabama

Date: 1956

Pages: 41

Keywords: Arsenic,Water quality,Plankton,Soil,Fish,Weed Control,Sodium arsenite.

Abstract:

The arsenic content was determined in water, plankton, soil, and fish from ponds treated at various rates with sodium arsenite. Two ponds received 8.0 p.p.m. As2O3 in 1955 and 4.0 p.p.m. As2O3 in 1956: two received 16.0 p.p.m. As2O3 in 1955 and 4.0 p.p.m. As2O3 in 1956: two received no arsenic in 1955 and 4.0 p.p.m. As2O3 in 1956: and the two check ponds received no arsenic in either year. Two of the ponds receiving arsenic in 1955 were subsequently drained in September, 1955, immediately refilled with water, allowed to stand for three months and then redrained. These ponds remained unfilled until they were refilled in May for the 1956 experiments. The other two ponds were drained in September, immediately refilled with water, allowed to stand for three months, drained and immediatley refilled. The ponds were then stocked with minnows, fed with organic meals for four months and again drained. In May, these ponds were refilled for the 1956 experiments.Despite repeated filling and draining of the ponds, considerable amounts of arsenic were retained by the bottom soils. On July 24, six weeks after refilling the ponds and just prior to the 1956 application of arsenic, the bottom soils contained 16.4 to 33.6 p.p.m. As2O3 in the top inch. At that time from 0.0 to 0.3 p.p.m. As2O3 was found in the water and 2,981 to 6,890 p.p.m. As2O3 on dry weight basis in the plankton. Seventy-two hours after sodium arsenite was applied, the arsenic appeared uniformly mixed throughout the water averaging 4.2 p.p.m. As2O3. The concentration of arsenic declined gradually to from 1.7 to 0.2 p.p.m. As2O3 at the termination of the experiment on October 10, 1956. It was also found in the 1956 experiment that, with one exception, there was little difference in the arsenic content of the waters from ponds receiving 8.0 and 16.0 p.p.m. As2O3 in 1955. Also there was little difference between ponds that had been drained and refilled two and three times between the test periods. The average dry weight of plankton per liter from July to October in the experimental ponds varied from 5.9 to 10.6 mg. dry weight per liter. The arsenic content of plankton from ponds receiving sodium arsenite increased gradually and after one month ranged between 3,690 and 10,087 p.p.m. As2O3 as dry weight. At the termination of the experiment, the arsenic content ranged between 1,635 and 3,600 p.p.m. As2O3. The arsenic content in the top inch of dry soil from arsenic-treated ponds increased gradually and at the termination of the experiment ranged between 14 and 54 p.p.m. As2O3. As the content of arsenic in the soil increased, the percentage which could be removed by leaching with distilled water increased. One fish from each pond was analyzed for arsenic when the concentration in the water had declined to less than 1.0 p.p.m. As2O3. Since zero to only trace amounts of arsenic were found in the flesh of fish from arsenic treated ponds, it appeared that the eating of fish from these ponds would not be dangerous to man or other animals. No arsenic was found in the water, soil, and fish, and only trace amounts in plankton from ponds not treated with arsenic in 1955 and 1956.

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