Chlorpropham is approved for use in the United States as a plant regulator and herbicide only on potatoes.[1] The use of CIPC was banned in the EU and UK in 2019 after it was not reauthorised for use due to toxicity concerns, with sales prohibited from January 2020.[2]
Uses
When it is used as an anti-sprouting agent for potatoes, the formulation is based on HN formulation, Hot Fogging.[3]
Commercial names include Bud Nip, Taterpex, Preventol, Elbanil, Metoxon, Nexoval, Stickman Pistols, Preweed, Furloe, Stopgerme-S, Sprout Nip, Mirvale, Bygran, ChlorIPC, Spud-Nic, Spud-Nie, Chloro-IFK, Chloro-IPC, Keim-stop, Triherbicide CIPC, OORJA.
For herbicide, an EC formulation is used so that it is dissolvable in water for spray in the field.[4]
Toxicity
Chlorpropham displays a low level toxicity profile, with no signs of acute toxicity after exposure of less than 1000 mg/kg/day. Long term exposure at high doses (≥ 1000 mg/kg/day) could cause reduction of body weight gain, decrease in hematocrit and hemoglobin, and increase in blood reticulocytes.
Regarding the carcinogenic risk, chlorpropham is classified by the EPA as group E (non-carcinogenic).[5] One of its metabolites is 3-chloroaniline.
The acceptable daily intake ranges from 0.03 mg/kg (FAO 2001[6]) to 0.05 mg/Kg (EPA 1996[5] and EC 2003[7]).
Stability
Chlorpropham is partially degraded in the environment under aerobic conditions (15% to 30% after 100 days) and partially hydrolysed in water solution (90% after 59 to 130 days).[7]
A study of the stability of chlorpropham in potatoes (estimated concentration of chlorpropham: 1.8 to 7.6 mg/kg at 10 days post-application) revealed that mean concentration of chlorpropham in the tuber decreased spontaneously by 24% and 42% at 28 days and 65 days postapplication respectively.[8] The study also showed that peeling removed 91–98% and washing 33–47%. Residues of chlorpropham were detected in the boiled potatoes, in the boiling water, in the French-fried potatoes and in the frying oil. According to this study, the theoretical dose for a 20 kg infant eating 100g of crude-peeled tuber would be 0.00018 to 0.00342 mg/kg.
^ abHEALTH & CONSUMER PROTECTION DIRECTORATE-GENERAL. chlorpropham(PDF). European commission. Archived(PDF) from the original on 2014-04-21. Retrieved 2014-03-25.
^Lentza-Rizos, Chaido; Balokas, Alfaios (2001). "Residue Levels of Chlorpropham in Individual Tubers and Composite Samples of Postharvest-Treated Potatoes". Journal of Agricultural and Food Chemistry. 49 (2): 710–4. doi:10.1021/jf000018t. PMID11262017.
Lentza-Rizos, Chaido; Balokas, Alfaios (2001). "Residue Levels of Chlorpropham in Individual Tubers and Composite Samples of Postharvest-Treated Potatoes". Journal of Agricultural and Food Chemistry. 49 (2): 710–4. doi:10.1021/jf000018t. PMID11262017.
David, B.; Lhote, M.; Faure, V.; Boule, P. (1998). "Ultrasonic and photochemical degradation of chlorpropham and 3-chloroaniline in aqueous solution". Water Research. 32 (8): 2451. doi:10.1016/S0043-1354(97)00477-6.
Wolfe, N; Zepp, R; Paris, D (1978). "Carbaryl, propham and chlorpropham: A comparison of the rates of hydrolysis and photolysis with the rate of biolysis". Water Research. 12 (8): 565. doi:10.1016/0043-1354(78)90134-3.
Wolf, D. C.; Martin, J. P. (1976). "decomposessition of Fungal Mycelia and Humic-type Polymers Containing Carbon-14 from Ring and Side-chain Labeled 2,4-D and Chlorpropham1". Soil Science Society of America Journal. 40 (5): 700. Bibcode:1976SSASJ..40..700W. doi:10.2136/sssaj1976.03615995004000050028x.