Insecticide, rodenticide

NOMENCLATURE

phosphine

IUPAC name phosphine 

Chemical Abstracts name phosphine 

Other names hydrogen phosphide  CAS RN [7803-51-2]  EEC no. 232-260-8 

aluminium phosphide

Common name aluminium phosphide (E-ISO, accepted in lieu of a common name); aluminum phosphide (JMAF, accepted in lieu of a common name)

IUPAC name aluminium phosphide 

Chemical Abstracts name aluminum phosphide 

CAS RN [20859-73-8]  EEC no. 244-088-0 

magnesium phosphide

IUPAC name magnesium phosphide 

Chemical Abstracts name magnesium phosphide 

CAS RN [12057-74-8]  EEC no. 235-023-7 

zinc phosphide

Common name zinc phosphide (E-ISO, JMAF, accepted in lieu of a common name); phosphure de zinc (F-ISO, accepted in lieu of a common name)

IUPAC name trizinc diphosphide 

Chemical Abstracts name zinc phosphide 

CAS RN [1314-84-7]  EEC no. 215-244-5 

PHYSICAL CHEMISTRY

phosphine

Mol. wt. 34.0  M.f. H3P  Form Colourless, odourless, flammable gas; (tech., garlic or rotting fish odour).  M.p. -132.5 ºC  B.p. -87.4 ºC  V.p. High  Henry 33 269 Pa m3 mol-1  S.g./density Gaseous 1.18 (air = 1)  Solubility In water 26 cm3/100 ml (17 ºC). In ethanol 0.5, ether 2, oil of turpentine 3.25 (all in vol. phosphine per vol. solvent, 18 ºC). In cyclohexanol 285.6 cm3/100 ml (26 ºC).  Stability Oxidised to phosphoric acid by oxidising agents and atmospheric oxygen.  F.p. It is spontaneously flammable in air (due to the presence of traces of other hydrides of phosphorus) with an explosion limit of 26.1-27.1 mg/l 

aluminium phosphide

Mol. wt. 58.0  M.f. AlP  Form Dark grey or yellowish crystals.  M.p. >1000 ºC  V.p. Very low, even at 1000 ºC  S.g./density 2.85 (25 °C)  Stability Though stable when dry, it reacts with moist air, violently with acids, producing phosphine. 

magnesium phosphide

Mol. wt. 134.9  M.f. Mg3P2  Form Yellow-green crystals.  M.p. >750 °C  S.g./density 2.055  Stability Stable when dry, but reacts with atmospheric moisture, and violently with acids, producing phosphine; used to generate this fumigant, reacting more rapidly than aluminium phosphide. 

zinc phosphide

Composition Tech. grade is 80-95% pure.  Mol. wt. 258.1  M.f. P2Zn3  Form Amorphous grey-black powder, with a garlic-like odour.  M.p. 420 ºC (when heated in the absence of oxygen)  V.p. Negligible in the dry state  S.g./density 4.55  Solubility Practically insoluble in water (decomposes slowly). Slightly soluble in carbon disulfide and benzene. Practically insoluble in alcohols.  Stability Stable when dry, but decomposes slowly in moist air; it is decomposed violently by acids to produce phosphine, which is a potent mammalian poison, and impurities which render the gas spontaneously flammable. 

COMMERCIALISATION

phosphine

Manufacturers United Phosphorus

aluminium phosphide

History Introduced as a source of fumigant insecticide by Dr. Werner Freyberg Chemische Fabrik (now Detia Freyberg).  Patents GB 461997; US 2117158  Manufacturers Ag Pesticides; Aimco; Detia Freyberg; Excel; Shenzhen Jiangshan; United Phosphorus; Young IL

magnesium phosphide

History Introduced by Degesch AG to generate phosphine and so fumigate stored foodstuffs.  Patents DE 923999 to Edmund  Manufacturers Detia Freyberg; United Phosphorus

zinc phosphide

History It has long been used as a poison against rodents.  Manufacturers Ag Pesticides; Aimco; Excel; Hacco; Liphatech; Motomco; United Phosphorus

APPLICATIONS

aluminium phosphide

Mode of action Insecticide and rodenticide which is a respiratory, metabolic, and nerve poison. Evolves a non-flammable mixture of phosphine (the toxicant), ammonia and carbon dioxide.  Uses Fumigation control of insect and rodent pests in stored grains (wheat, rye, barley, rice, sorghum, maize, etc.), seed grains, grain products (flour, noodles, semolina, etc.), pulses (peas, beans, lentils, etc.), tobacco, tapioca (roots and flour), oil seeds, expeller cake, nuts, nut kernels, dried fruit, coffee beans, cocoa beans, tea, etc.; and in empty warehouses, silos, packing materials, transport containers, etc.  Phytotoxicity Living plants, fresh vegetables and fruits, with few exceptions, should not be fumigated.  Formulation types GE; Fumigant.  Selected tradenames: 'Agtoxin' (Ag Pesticides); 'Al-Phos' (Aimco); 'Celphide' (Excel); 'Celphos' (Excel); 'Phostek' (Killgerm); 'Phostoxin' (Detia Degesch); 'Quickphos' (United Phosphorus); 'Shaphos' (Sanonda)

magnesium phosphide

Mode of action Insecticide and rodenticide which is a respiratory, metabolic, and nerve poison. Liberates phosphine, which is the toxicant.  Uses As for aluminium phosphide. Also used for control of moles, voles, rats, hamsters, and rabbits by fumigation of burrows.  Phytotoxicity Living plants, fresh vegetables and fruits, with few exceptions, should not be fumigated.  Formulation types GE; Fumigant.  Selected tradenames: 'Magnaphos' (United Phosphorus); 'Magtoxin' (Detia Degesch)

zinc phosphide

Mode of action Rodenticide (for single ingestion). Reacts with stomach acids to liberate poisonous phosphine, which enters the bloodstream, and results in damage to the liver, kidneys and heart.  Uses Bait rodenticide for control of rats, mice, voles, ground squirrels, and gophers. Also used in tracking powder form for house mouse control.  Formulation types AB; CP; PA; RB; SB.  Selected tradenames: 'Agzinphos' (Ag Pesticides); 'Commando' (Excel); 'Ratol' (United Phosphorus); 'Rattekal-Plus' (Frunol); 'Zawa' (Sanonda); 'Zinc-Tox' (Aimco)

OTHER TRADENAMES

aluminium phosphide

'Celphine' (Excel); 'Detia-Gas-Ex-B' (and Ex-T, Ex-P) (Detia Degesch); 'Fumitoxin' (Pestcon); 'Gran Quick Phos' (Agricultura Nacional); 'L-Fume' (Excel); 'Luxan Talunex' (Luxan); 'Talunex' (Luxan) Discontinued names: 'Amos Talunex' * (Luxan); 'DeliciaGastoxin' * (Delicia)

magnesium phosphide

'Degesch Plates' (Detia Degesch); 'Fumi-Cel' (Degesch America); 'Fumi-Strip' (Degesch America) Discontinued names: 'Detiaphos' * (Detia Degesch)

zinc phosphide

'Arrex' (BASF); 'Foke BA' (Vipesco); 'Ridall-Zinc' (Liphatech) Discontinued names: 'Denkarin Grains' * (Denka)

ANALYSIS

phosphine

Phosphine present during fumigation can be determined using commercially available detector tubes, by glc (B. Chakrabarti & H. E. Wainman, Chem. Ind. (London), 1972, p. 300) or by aspiration through aqueous mercuric chloride and measuring the change in electrical conductivity (A. H. Harris, Proc. GASGA Tech. Seminar, TDRI, Slough, 1986). Methods for residues in foods reviewed, with details by J. L. Daft in Comp. Anal. Profiles, p. 274. 

aluminium phosphide

Product and residue analysis depend upon determining the phosphine liberated by acid treatment. Measurement is by glc (B. Berck et al., J. Agric. Food Chem., 1970, 18, 143; T. Dumas, J. Assoc. Off. Anal. Chem., 1978, 61, 51; Anal. Methods Residues Pestic., 1988, Part II, M8; K. A. Scudamore, Anal. Methods Pestic. Plant Growth Regul., 1988, 16, 251; K. A. Scudamore & G. Goodship, Pestic. Sci., 1986, 37, 385). 

magnesium phosphide

Product analysis by determining the phosphine liberated on treatment with acid, by glc (T. Dumas, J. Assoc. Off. Anal. Chem., 1978, 61, 51) or phosphate produced after reaction with bromine water (R. B. Bruce et al., J. Agric. Food Chem., 1962, 10, 18). 

zinc phosphide

Product analysis by reaction with acid, the phosphine produced is estimated by titration (CIPAC Handbook, 1970, 1, 703), or oxidised to phosphoric acid which is estimated by standard methods (J. W. Elmore & F. R. Roth, J. Assoc. Off. Agric. Chem., 1943, 26, 559; 1947, 30, 213; B. L. Griswold et al., Anal. Chem., 1951, 23, 192). 

MAMMALIAN TOXICOLOGY

phosphine

Reviews FAO/WHO 6, 7 (see part 2 of the Bibliography).  Skin and eye No absorption through the skin.  Inhalation Powerful respiratory poison. LC50 (4 h) for rats 11 ppm (0.015 mg/l) (R. S. Waritz & R. M. Brown, Am. Ind. Assoc. J., 36, 452-458 (1975)). Inhalation at 10 mg/m3 can cause death within 6 h, and at 300 ml gas/m3 for one hour, there is danger to life. No symptoms of chronic poisoning are observed.  ADI (JMPR) Not necessary on basis of no residue in food [1966].  Other Phosphine is a potent, acute mammalian poison, but feeding trials with fumigated foodstuffs have shown no chronic effects on rats (U. Hackenberg, Toxicol. Appl. Pharmacol., 1972, 23, 147).  Toxicity class EPA (formulation) I 

aluminium phosphide

Oral Acute oral LD50 for rats 8.7 mg/kg.  EC hazard F; R15/29| T+; R28| R32 

magnesium phosphide

Oral Acute oral LD50 for rats 11.2 mg/kg.  EC hazard F; R15/29| T+; R28 

zinc phosphide

Oral Acute oral LD50 for rats 45.7, sheep 60-70 mg/kg (M. A. Nekrasova, Sb. Rab., Leningr. Vet. Inst., 1964, No. 25, 372).  Skin and eye Acute percutaneous LD50 for rabbits 2000-5000 mg/kg. Non-irritating to skin and eyes.  Toxicity class WHO (a.i.) Ib; EPA (formulation) I  EC hazard F; R15/29| T+; R28| R32 

ECOTOXICOLOGY

phosphine

Fish LC50 (96 h) for rainbow trout 9.7 ´ 10-3 ppm.  Daphnia EC50 (24 h) 0.2 mg/l. 

zinc phosphide

Birds Acute oral LD50 for mallard ducks 37.5, bobwhite quail 13.5, pheasants 9 mg/kg (D. W. Hayne, Mich. Agric. Exp. Stn., Q. Bull., 1951, No. 33, 412); for fowls, the lethal dose is 7-17 mg/kg (G. D. Shearer, J. Comp. Pathol. Therap., 1945, 55, 301).  Fish Acute LC50 for bluegill sunfish 0.8, rainbow trout 0.5 mg/l. 

ENVIRONMENTAL FATE