Termite control

Constituents. Complex halogenated organic compounds have been widely used in commerce in the last fifty years. A few representative examples are shown in Eigure 9 pentachlorophenol has been widely used as a wood preservative, and also for termite control. 

Cyclodienes. These are polychlorinated cycHc hydrocarbons with endomethylene-bridged stmctures, prepared by the Diels-Alder diene reaction. The development of these insecticides resulted from the discovery in 1945 of chlordane, the chlorinated adduct of hexachlorocyclopentadiene and cyclopentadiene (qv). The addition of two Cl atoms across the double bond of the ftve-membered ring forms the two isomers of chlordane [12789-03-6] or l,2,4,5,6,7,8,8-octachloro-2,3,3t ,4,7,7t -hexahydro-4,7-methano-lJT-indene, QL-trans (mp 106.5°C) and pt-tis (32) (mp 104.5°C). The p-isomerhas signiftcantiy greater insecticidal activity. Technical chlordane is an amber Hquid (bp 175°C/267 Pa, vp 1.3 mPa at 25°C) which is soluble in water to about 9 fig/L. It has rat LD qS of 335, 430 (oral) and 840, 690 (dermal) mg/kg. Technical chlordane contains about 60% of the isomers and 10—20% of heptachlor. It has been used extensively as a soil insecticide for termite control and as a household insecticide. 

Chlordane-induced mortality of the long-billed curlew (Numenius americanus) has been documented at least four times since 1978, despite restriction of technical chlordane use since 1980 to subterranean applications for termite control (Blus et al. 1985). Death of these curlews was probably due to over-winter accumulations of oxychlordane of 1.5 to 5.0 mg/kg brain FW and of heptachlor epoxide at 3.4 to 8.3 mg/kg — joint lethal ranges for oxychlordane and heptachlor epoxide in experimental birds — compared to 6 mg/kg brain for oxychlordane alone and 9 mg/kg for heptachlor epoxide alone (Blus et al. 1985). Additional research is needed on toxic interactions of chlordane components with each other and with other chemicals in the same environment. 

Chlordane levels in human blood were comparatively elevated among individuals living in residences treated with chlordane during the past 5 years, and in termite control operators. Oxychlordane levels were usually significantly higher than /ra/u-nonachlor, except among those who consumed large quantities of fish (Wariishi et al. 1986 Wariishi and Nishiyama 1989). 

Shortly after chlordane was applied to wooden huts in Australia for termite control, large numbers of dead skinks (Morethia boulengeri, Lerista puctorittata) and frogs (Litoria caerulea, L. peronii) were discovered, presumably killed by the chlordane (Henle 1988). Toad (Bufo arenar-ium) embryos survived 0.5 mg technical chlordane/L for 8 days, but died by day 20 all embryos held in 15 mg/L were dead by day 15 (Juarez and Guzman 1984). For tadpoles of the common toad (Bufo bufo), a 48-h LC50 of 2 mg/L was reported (WHO 1984). 

Sodium molybdate and other molybdenum compounds in toxic baits have potential for termite control (Brill et al. 1987). Baits containing 1000 mg Mo/kg were fatal to 99% of the termite Reticu-litermes flavipes in 48 days. After 8 to 10 days, termites became steel-gray in color, but appeared otherwise normal. Mortality began only after day 16. Termites did not avoid the poisoned bait, even at concentrations of 5000 mg Mo/kg. Yoshimura et al. (1987) reported similar results with another species of termite sodium molybdate killed 100% of the workers in a colony of Copotermes formo-sanus within 24 h after eating filter paper treated with a 5% solution. Some other species of insects — including fire ants (Solenopsis sp.) and various species of beetles and cockroaches — were not affected when exposed to baits containing 5000 mg Mo/kg for 48 days (Brill et al. 1987). 

The main application fields of pyrethrins are limited to indoor use because of their instability to heat, light, and oxygen. Since the absolute configuration of the six insecticidal components of pyrethrins were elucidated in 1958, various researches on structural modifications have been carried out actively in many countries for more than half a century, leading to the development of a variety of photostable pyrethroids. As a result, they have been widely put into outdoor use for agriculture, forestry, animal health, termite control, and so on. 

Currently, other minor applications include treatment of felled logs for bark beetles, termite control, control of wax moths in beehives, spot treatment of milling machinery, Japanese beetle control in ornamental plants, and as a chemical intermediate for dyes, resins, waxes, and gums (HSDB 1989). 

Use Nonsystemic contact and ingested insecticide for termite control. 

Uses Manufacture of insecticides (termite control), algicides, herbicides, fungicides, and bactericides wood preservative. Manufacture of pentachlorophenyl laurate to mothproofing fabrics. 

Uses. Insecticide currently approved for underground termite control only... 

Uses. Insecticide for boll weevil control and termite control currently banned or severely restricted in many countries... 

Uses. Wood preservative insecticide for termite control preharvest defoliant general herbicide fungicide... 

Chlordane - America s leading lawn and garden insecticide. Used extensively by pest control operators for termite control, because of its long lasting effectiveness. 

Human exposure limits through air exposure are to be applied at a plant that manufactures Heptachlor, C10H5CI7. Heptachlor is a chemical that is currently restricted in use to termite control, because of exposure concerns. These limits are given in ppm(v), but the release to the air is determined in g/s. Applying the volume flow with the current ventilation system and the volume of the plant in a complete mix reactor assumption resulted in a vapor phase concentration of 0.1 M-g/m. What is the vapor phase concentration in ppm(v) ... 

Methyl bromide is used as a fumigant for soils (the agricultural use shown in Table 12.7) and shipments of fruits and vegetables as well as for buildings for termite control (shown as structural purposes in Table 12.7). Large amounts are released during biomass burning (e.g., see Mano and Andreae, 1994 Cicerone, 1994)... 

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