# US 4,398,937 A · Selective algaecides for control of cyanochloronta

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- Number: US 4,398,937 A
- Document ID: US4398937A
- Status: Granted
- Kind: A
- Application number: 06/308,987
- Filed: 1981-10-06
- Granted: 1983-08-16
- Earliest claimed: 1981-10-06
- Assignees: The University of Southern Mississippi
- Inventors: Robert T. van Aller; George F. Pessoney
- Web page: https://patentgrep.com/patent/US4398937A

## CPC

- A01N 37/36: containing at least one carboxylic group or a thio analogue, or a derivative thereof, and a singly bound oxygen or sulfur atom attached to the same carbon skeleton, this oxygen or sulfur atom not being a member of a carboxylic group or of a thio analogue, or of a derivative thereof, e.g. hydroxy-carboxylic acids
- A01N 37/02: Saturated carboxylic acids or thio analogues thereof; Derivatives thereof
- A01N 37/06: Unsaturated carboxylic acids or thio analogues thereof; Derivatives thereof
- A01N 37/42: containing within the same carbon skeleton a carboxylic group or a thio analogue, or a derivative thereof, and a carbon atom having only two bonds to hetero atoms with at the most one bond to halogen, e.g. keto-carboxylic acids
- A01N 43/20: three- or four-membered rings
- A01N: PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF (preservation of food or foodstuff A23); BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES (preparations for medical, dental or toiletry purposes which kill or prevent the growth or proliferation of unwanted organisms A61K); PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS

## Abstract

This invention relates to the selective control of algae in ponds, sewage lagoons, cooling towers, lakes, and other bodies of water, including managed bodies of water, and deals particularly with the use of certain long-chain fatty acids and salts thereof for chemical control of Cyanochloronta (blue-green algae). Stimulation of Chlorophycophyta (green algae) is achieved by the use of one embodiment of this invention. Application of the invention to bodies of water used in aquaculture eliminates earthy, musty flavors and other disagreeable flavors associated with blue-green algae in fish and other cultured organisms. Furthermore, a more balanced diversity of planktonic organisms can be maintained which makes oxygen depletion problems more manageable.

## Claims

### Claim 1

A method of selectively controlling the growth of blue-green algae and yellow-green algae while maintaining a desirable balance of planktonic organisms in bodies of water in which populations of harmful blue-green algae are reduced in numbers leaving green algae and their oxygen producing capacity and food value substantially unreduced comprising adding from about 0.01 to about 100 ppm of a fatty acid compound selected from the group consisting of 9, 10-dihydroxystearic acid, Dodecanoic acid, Linoleic acid and Ricinoleic acid to the aqueous medium.

### Claim 2 (depends on 1)

The method of claim 1 wherein said fatty acid is in the form of a water soluble salt.

### Claim 3 (depends on 2)

The method of claim 2 wherein said water soluble salt is selected from the group consisting of sodium salts and potassium salts.

### Claim 4 (depends on 1)

The method of claim 1 wherein the fatty acid is 9,10-dihydroxystearic acid.

### Claim 5 (depends on 1)

The method of claim 1 wherein the fatty acid is linoleic acid.

### Claim 6 (depends on 1)

The method of claim 1 the fatty acid is dodecanoic acid.

### Claim 7 (depends on 1)

The method of claim 1 wherein the fatty acid is ricinoleic acid.

### Claim 8 (depends on 1)

The method of claim 1 wherein the fatty acid is added to the aqueous medium in an amount of from about 0.1 to about 10 ppm.

### Claim 9

A method of substantially eliminating blue-green algae from sewage lagoons comprising adding from about 0.01 to about 100 ppm of a fatty acid compound selected from the group consisting of 9, 10-Dihydroxystearic acid Dodecanoic acid, Linoleic acid and Ricinoleic acid to said sewage lagoon.

### Claim 10

A method of maintaining a desirable balance of planktonic organisms in bodies of water comprising adding from about 0.01 to about 100 ppm of a fatty acid compound selected from the group consisting of 9, 10-Dihydroxystearic acid, Dodecanoic acid, Linoleic acid and Ricinoleic acid to said body of water.