Chemistry:Profluralin
Profluralin is a dinitroaniline herbicide used preëmergently to control annual grasses and broadleaf weeds, in cotton, soybeans, peanuts, sunflower, cabbage, cauliflower, tomato and others.[1] Profluralin has largely fallen out of use.[2] It rose out of the related, still in common use, trifluralin.[3] It was commercialised in the 1970s.
Commercialisation
Profluralin, first reported in 1973, was introduced by Ciba-Geigy and patented.[4]
It was sold under the tradenames "Pregard" and "Tolban" (Ciba-Geigy),[4][2] registered in August 1975 and expiring in April 1984. Tolban was a 45% profluralin emulsifiable concentrate.[5] 48,000 pounds (22 t) was used in the US in 1974.[6] The USGS estimates that 5 to 65 thousand pounds (2.3 to 29.5 t) was used in 1994, with no usage after.[7]
As of 2012, Pregard and Tolban are discontinued.[4]
Mode of action
It is absorbed through roots and shoots, applied at 0.75-1.5 kg/Ha (active ingredient), formulated as an emulsifiable concentrate.[4]
Environmental behaviour
Environmental decomposition by microörganisms happens in soil and water. Typical soil half-lives for profluralin are 80-160 days. Profluralin is adsorbed into plantmatter, so there is potential that it stay in crops after harvest. It is practically non-toxic to birds and mammals, though bees and fish are affected. If applied in high doses to rats, they may exhibit ataxia, slower breathing, salivation, prostration, hyperactivity or dyspnea. It interacts with dsDNA via electrostatic binding.[1] There is no significant leaching through soil.[4]
Microörganisms in sewage cometabolise profluralin, trifluralin, fluchloralin and nitrofen; i.e. enzymes from other active metabolic processes also break up these chemicals. Over 88 days, profluralin levels reduced by 87% under aerobic conditions, into 9 metabolite products. Discontinuous anaerobic conditions slowed the process to a 23% reduction in the same time, with 5 metabolites.[8]
Safety
Profluralin is not toxic, not considered a carcinogen. Human harm is not expected, outside of eye irritation. Profluralin is very toxic to fish though, and is theorised to bioaccumulate in them.[9] It is non-irritating to skin, though moderately so on eyes.[4]
Chemical properties
Pure profluralin is soluble in most organic solvents, e.g. n-octanol (220 g/L), or in ethanol, acetone, xylene and n-hexane. When made, it is chemically stable for at least three years. It decomposes under UV light, or at temperatures over 180°C (356°F), though solutions slowly hydrolyse at about 100°C (212°F) with a half-life of 6 hours, at pH 3-10.[4]
References
- ↑ 1.0 1.1 Morawska, Kamila; Jedlińska, Katarzyna; Smarzewska, Sylwia; Metelka, Radovan; Ciesielski, Witold; Guziejewski, Dariusz (September 2019). "Analysis and DNA interaction of the profluralin herbicide". Environmental Chemistry Letters 17 (3): 1359–1365. doi:10.1007/s10311-019-00865-1. Bibcode: 2019EnvCL..17.1359M.
- ↑ 2.0 2.1 Hertfordshire, University of. "Profluralin (Ref: CGA 10832)". http://sitem.herts.ac.uk/aeru/ppdb/en/Reports/2843.htm.
- ↑ Moore, Mark (March 2012). "Top 10 classic herbicides". https://www.farmprogress.com/crop-protection/top-10-classic-herbicides.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Macbean, C. (2012). A World Compendium The Pesticide Manual (16th ed.). Hampshire, UK: British Crop Protection Council. ISBN 978 1 901396 86 7.
- ↑ "Tolban 4E Herbicide pesticide information". https://www.pomerix.com/pesticides/tolban-4e-herbicide.
- ↑ "Pesticide Usage Survey of Agricultural, Governmental, and Industrial Sectors in the United States, 1974". EPA. 1977. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=91012P4O.txt.
- ↑ "2019 Pesticide Use Maps". USGS. https://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2019&map=PROFLURALIN&hilo=L&disp=Profluralin.
- ↑ Jacobson, Stuart N.; O'Mara, Nancy L.; Alexander, Martin (November 1980). "Evidence for Cometabolism in Sewage". Applied and Environmental Microbiology 40 (5): 917–921. doi:10.1128/aem.40.5.917-921.1980. Bibcode: 1980ApEnM..40..917J.
- ↑ Cite error: Invalid
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Links
- Profluralin in the Pesticide Properties DataBase (PPDB)
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