52- 68-6 Trichlorfon

IUPAC name Dimethyl 2,2,2-trichloro-l-hydroxyethylphosphonate Molecular formula C gCbCUP Toxicity class USEPA II WHO II 

Uses Trichlorfon is a pale, clear, white, or yellow crystalline solid with an ethyl ether odor. It is a solid at room temperature. Trichlorfon is grouped by the USEPA under GUP. Trichlorfon is used for the control of a variety of insect pests, (e.g., cockroaches, crickets, silverfish, bedbugs, fleas, cattle grubs, flies, ticks, leafminers, leafhoppers). It has extensive use in agriculture, applied to vegetable, fruit, and field crops. 

It also is used for the control of internal parasites affecting domestic animals and livestock. Trichlorfon is available in dust, emulsifiable concentrate, granular, fly bait, and soluble powder formulations with the percentage active of ingredient ranging from 40% (soluble powder) to 98% (technical). Trichlorfon is a selective insecticide, meaning that it kills selected insects.28 

The symptoms of acute exposure include headache, giddiness, nervousness, blurred vision, weakness, nausea, cramps, loss of muscle control or reflexes, convulsion, or coma. It has been suggested that impurities or additives may be associated with some cases of delayed polyneuropathy (damage to nerve cells) attributed to ingestion of large amounts of trichlorfon.87-90 

OPs have been in use for several decades as important chemicals for the control of crop pests. With their chemical and biochemical reactions, OPs have been well established as extremely poisonous chemicals. This classification is due to the inhibition of the marker enzyme ChE, which is produced in the liver. Blood enzymes provide an estimate of tissue enzyme activity. After acute exposure to OPs or a nerve agent, the erythrocyte enzyme activity most closely reflects the activity of the tissue enzyme. Once the OPs inhibit the tissue enzyme, it cannot hydrolyze ACh, and the accumulation stimulates the affected organ. Based on the manner of exposure (dose and duration) to different OPs, a series of toxicity signs and symptoms set in the organism, leading to death. These are important aspects to be closely monitored among pest control operators and occupational workers exposed to OPs. 

Molecular formula C4H8CI3O4P Molecular weight 257.44 CAS Registry No 52-68-6 Merck Index 13, 9696 

Mobile phase MeOH THF l mM pH 3.0 sodium octanesulfonate 10 0.1 89.9 Flow rate 2 

Hannant, M.E. Becker, R.E. High-performance liquid chromatographic method using ultraviolet detection for measuring metrifonate and dichlorvos levels in human plasma, J.Chromatogr., 1992,575,99-103. 

---

Under current regulations, chemicals allowed for use in various European countries (Table 3) are either fully Hcensed for aquacultural use (oxytetracycline, oxolinic acid) or can be prescribed by veterinarians if they are Hcensed for use on other food animals (14—16). In addition, previously unHcensed chemicals that are appHed to the water (topicals) may now be used under a grandfather clause if no one questions their safety. The question of whether a chemical is a medicine or a pesticide has also been addressed. Eor example, dichlorvos (Nuvan 500 EC) was initially designated as a pesticide in the United Kingdom, but was later categorized as a medicine. A similar product, trichlorfon (Masoten), was treated the same way in the United States. 

Kicuchi and Saito used carbon Empore disks in combination with SDB-XD Em-pore disks to extract polar (methamidophos, acephate and trichlorfon) and nonpolar pesticides (diazinon, chloroneb and simazine) from water. The water sample (500 mL) was passed through the disk and the disk simultaneously eluted with 30 mL of acetone-ethyl acetate (1 1). The samples were concentrated and analyzed by GLC/MS. 

Trichlorfon cabbage, tomatoes, melons, cucumbers, potatoes, cereals, beans 1.0 0.1 E10... 

Pesticides contaminate not only surface water, but also ground water and aquifers. By 1990 in the USSR, 15% of all pesticides used were detected in underground water [29]. Pesticides were detected in 86% of samples of underground water in Ukraine in 1986-87 (including DDT and its metabolites, HCH, dimethoate, phosalone, methyl parathion, malathion, trichlorfon, simazin, atrazine, and prometrin). In actual fact, the number of pesticides was apparently larger, but the laboratory was able to determine the content of only 30 of the 200 pesticides used at that time in Ukraine [29]. In the 1960s, in the Tashkent and Andizhan oblasts of Uzbekistan, the methylmercaptophos content in the water of studied well shafts was, by clearly underestimated data, 0.03 mg/l (MPC was 0.01 mg/l), of DDT was 0.6 mg/l (MPC was 0.1 mg/ I), and of HCH was 0.41 mg/l (MPC was 0.02 mg/l) [A49]. 

Official Soviet science considered that OPPs did not remain in the soil for very long, and the products resulting from its decay were of low toxicity [21, 30]. In fact trichlotfon, for example, decays slowly in acid soils. It more actively dehydrochlorinates in alkaline media, but it then forms highly toxic dichloifos [33]. Parathion may remain in soil for up to 16 years [34]. Cases are known when phosalone and chlorpyrifos remain in soil for up to two years [3, 20]. Methyl parathion and trichlorfon were detected in the Kilmez region of the Kirov Oblast in an underground chemical repository 20 years later [3]. 

Suppression of mitotic activity Trichlorfon, carbaiyl, thiram, nitro-aldicarb... 

Stable OCPs were not the only pesticides found in food products, as was inevitable for the USSR in the 1960s all types of OPPs were also detected, including phenkapton [38] and dichlorvos [30], menazon [41] and ph-enthoate [50], trichlorfon [14], phosalone [60] and tetrachlorvinfos [56]. 

In Table 3.16, shaded pesticides are those detected in products where they should have been absent, because 1) they were banned (DDT, heptachlor) 2) their presence in all food products was banned (methyl parathion, 2,4-D, etc.) 3) they were not permitted to be present in particular food products (trichlorfon in meat and dairy products) and 4) they were not permitted to be used with particular crops. Unfortunately, practically the entire table is shaded, which shows that all regulations were violated. 

---