Document z489GNnLa3anwjjGa6qERQQm

lll^iifh' *H ft'nfi'i* irwirfn *4+ The Role of Chlorinated Polyphenyls in Improving Lindane Residues1 I. IIor.nbtein and W. N. Sullivan, U.S.D.A., Ayr. Res. Adm., Bureau of' Entomology and Plant Quarantine . I The use of lindane and other volatile ity consists essentially in the formation ? i insecticides to leave toxic residues on of a supersaturated solution, which crys- ; i surfaces presents several problems. With tallizes at the film surface only. This [ lindane deposits the following problems crystallization lowers the concentration of } may be encountered: insecticide in solution at the film surface . f (I) The appearance of a crystalline deposit may and results in a diffusion of insecticide . 1 be objectionable. from the body of the coating to this sur | (`J) It evaporates so rapidly that repeated treat- face. If we are dealing with a metastablc . ; i ments may be necessary. (3) The crystals may be removed by mechanical contact. equilibrium such as exists in supersaturated solutions, a scratch or a blow may -* " | (4) Weathering may remove the toxicant in out cause crystallization within* the coating, ; door applications. and the slow diffusion of insecticide to the - ' j 1 * (5) On very porous surfaces there may be a rapid loss of toxicity through sorption of the insect!-cide. surface will stop and the toxicity of the film will quickly drop. If the surface be . ; (6) The cost of lindane is high. comes case-hardened with time, as do ; A fihn-forming material in which the many paints and coatings, this diffusion ' ' : insecticide is soluble will prevent crystal lization, reduce the volatilization rate, process can no longer take place and again the toxicity of the surface quickly drops. * and if the proper material is chosen, pro SUITABLE l'ltOl'EKTIES OF ClIEOllINATED ' V !' : vide a tight bond to the surface being treated. The problem of cutting down Polypiiknyls.--It has been found after a number of trials that a mixture of chlor- j sorption on porous surfaces is essentially mated terphenyls available commercially \ [ f ; one of finding appropriate methods of application. Prolonged insecticidal effectiveness has been obtained by incorporating the toxi- appears to have the physical properties that make it suitable as a film-forming carrier for lindane. This material is produced by the pyrolysis of benzene to yield ( j ; i cant.in a nonvolatile oil. However, on porous surfaces this oil solution penetrates a mixture containing 80 per cent of bi phenyl and 20 per cent of isomeric ter- j ; j i* j 1 rapidly and toxicity is.soon lost, and on nonporous surfaces a wet oily film is left which may be very undesirable. Lindquist ct al. (19-15), Campbell & West (194-la, b), and others have suggested phenyls, separation of the terphenyl fraction, and chlorination until a 00 per cent chlorine content is attained. This material is available as Aroelor 5400 and is inex pensive in bulk quantities. It has been . , . i the incorporation of DDT in paints, safely used for a variety of industrial j ! j Block (1948) has made a comprehensive survey of the field of insecticide coalings, In general, oil films, oil-modified resins, purposes. However, as a precautionary measure pharmacological studies should be made to determine possible toxicity. j ; ; or rosin derivatives produced coatings with DDT having poor insecticidal quality. Among paint vehicles from natural The properties of this product that make it particularly suitable are as fol lows: ' ; , : : > products an asphalt varnish derived from gilsonitc appeared to be satisfactory, Water-dispersible vehicles, such as casein and glue, were found not to be so toxic as expected. Various .synthetic resins including urea-formaldehyde appeared proinis- (1) It is n good solvent for lindane, and thereby contributes to the lowering of its vapor pressure and prevents its crystal lization. (2) It is inert, resistant to oxidation, nonflammable, and does not. afford a medium for fungus growth. Once the film ' 1 I ! 'g. .... . In those insecticidal paints and coatings has been deposited and the solvent evap- ! the insecticide is of low solubility in the : film-forming material.Tt is assumed that * lVfM'ntci! tt tlie meeting of the American A**oci*tion of | the mechanism of prolonging their toxic- lUit.r.ctmoihic KiitouiuKigiali at IMiiUilctpliia, l1*., IVcriubcf \ \ 937 DSW 255050 i STLCOPCB4060741 938 Journal of Economic Entomology Vol. No. 6 orated, no further change in tic physical properties of llie film is to he expected. (3) When properly applied, a 1:1 or a 1:2 mixture of lindane and chlorinated terphenvls provides a surface .that is slightly tacky. Insects passing over such a surface appear lo pick up the insecticide more readily than when they travel across a hard surface. Thus, when lindane is in corporated in a vinyl-type polymer, a clear transparent film results but because of the surface hardness the insect toxicity is cpiitc low. Decreased Volatility ok Lindane in Mixtures with Chlorinated Tek- piiknyls.--The rale of volatilization of lindane at a given temperature is a func tion of its vapor pressure, the surface area available for evaporation per unit mass, and the concentration of lindane in the air surrounding the- deposit. The last factor depends iargely on the air exchange in the area treated. The reduction in vapor pressure in lindane-chlorinated terphcnyl mixtures accounts in part for the extended life of the material. Of importance too is the decrease in surface area per unit mass of lindane. The relatively large surface as sociated with lindane crystals is no longer . available for vaporization. Instead evap oration takes place from a relatively smooth film having considerably less ex posed surface. In contrast to crystallization from a supersaturated film, it is the evaporation of lindane that creates the lack of balance in concentration that kcqps lindane diffus ing to the surface from the body of the coating. Thus, higher concentrations of insecticide can be utilized completely and longer lasting residues arc obtainable. Comparative Toxicity of Lindane and Lindane-Chlorinated Terpiienyl Mixtures.--In previous tests we com pared the effectiveness against the Ameri can cockroach, Periplaneta amcricana (L.), of deposits of 100 mg. of lindane per square foot with and without 200 mg. of chlorinated tcrphenyls on alum inum surfaces (Sullivan & Ilornslein 1953). Lindane alone gave a 30 per cent kill after 30 days, a 3 per cent kill after 60 days and no kill at the end of 90 days. The lindane-chlorinated terphcnyl mix ture still gave 80 per cent kill at the end of 90 days. Tsao et al. (1953) obtained simi lar results against house flies. Musea do- mcstica L. On masonite, a porous surface, similar deposits gave only about a 20 per cent kill of American cockroaches after 10 days. Other porous surfaces, such as carpeting and plywood also gave poor results when lindane or lindanc-chlori- nated terphcnyl mixtures were applied. Our knowledge rtf the ability of lindane- chlorinated terphcnyl mixtures to with stand outdoor weathering is limited. However, 1 lie following experiment is of interest. A low-pressure aerosol containing 5 parts each of lindane and chlorinated tcrphenyls, 40 parts of methylene chloride and 50 parts of Freon-12 (by weight) was sprayed on the leaves of a small willow tree and subjected lo the summer weather conditions prevailing at Beltsvillc, Mary land. At the end of 30 days a leaf sample was found on analysis to contain 250 micrograms of lindane per square inch. There were no obvious ill effects on the leaves. At the end of 60 days, another leaf sample contained about 200 micro grams of lindane per square inch. At the end of 70 days flics caged around a portion of a treated branch showed 90 per cent mortality and all those on untreated check branches were alive/ . All bough the fumigating effect of lin dane vapors is materially cut down by the lowered rale of vaporization, it is by no means eliminated. Two weeks after lindane chlorinated terpiienyl mixtures were painted on the inside of a large glass ves sel 50 per cent of caged flies not in contact with tlic treated surface were killed after a 10-minutc exposure. Methods ok Application to Porous Surfaces.--We have tried in several ways to obtain better surface coatings on por ous materials and have selected unpainted plywood as a typical porous surface for test purposes. Wetting the surface down with water and then applying as a spray a solution of lindane and chlorinated tcrphenyls in a low-boiling solvent appears promising. The water prevents the oil from wetting and therefore penetrating the porous surface, and the solvent quickly evaporates to leave a surface deposit of lindane-chlor inated tcrphenyls. Pressurized sprays containing low- boiling solvents give good surface de posits. By adjustment of the concentra tion of a very volatile solvent, such as methylene chloride, in the pressurized- oS\N 255051 ""''sr iljWlffS.lf i iiii.wi I I IIUJWITI.HII) 'T u>wh>mhjui STLCOPCB4060742 mtfih V, No. 6 1 I surface, *20 per j ! es after ] such as j re jK>or ; ic-chlori- died, tfmdanc- . with- Similed. : nt is of staining 'urinated chloride .... rM) was I willow i ! weal her | *. Mary- \ f sample .-sin 2.30 J .; re inch. > on t he another i j i micro- ;. At the t portion ; 1 i per cent r/ treated ; t of linn l>y the es by no rlindane -s were ra ss ves- vCOIllaCt 3 after a i ! j ' j : I ! IV, ito us '->otl ways - on jKjr- opainled -face for ! | ! j i 1 water dot ion of f.vls in a -mg. The ting and surface, unites to ne-elilor- g lowface de`Kfjernlni, Mjeli as .-ssuriwal- i ; ; | | ; ( | ; ' I J December 1953 ITornstein & Sullivan: Improving Lindane Residues 039 spray formulation, most of the solvent will evaporate before the lindane-chlor inated tcrphcnyl mixture reaches the sur face. The highly viscous particles of this mixture will then have little tendency to penetrate into the porous material. The lindane-chlorinated tcrphcnyl mix ture may bo precipitated out of solution just as it hits the surface. A nearly sat urated solution of this mixture in acetonewater is prepared. The surface to be treated is wetted down with water. In this instance it is not the repellcncy of thcoil and water, but the solubility of the acetone in water that gives the desired result. The water precipitates the lindane-chlorinated torphenyl mixture out of the acetone solu tion. After evaporation of the acetone and water, the lindane-chlorinated tcrphcnyl mixture will be left as a spotty but ad herent deposit; however, for many pur poses, where-appearance is not of prime importance, this may prove a useful method of application. A homogenized suspension of a xylene solution of lindane and chlorinated terphcnyls in water also gave promising results. To obtain a fairly stable homog enized suspension, a xylene solution hav ing a specific gravity of 1 was prepared by adding 15 parts each of lindane and chlorinated terphcnyls to GO parts of xylene (all parts by weight). The closer the densities of the mutually insolu ble phases the more stable will be the homogenized suspension. This solution was then homogenized with water so that the final suspension contained about 2 per cent each of lindane and chlorinated tcrphcriyls and a watcr-to-xylenc ratio of about 10 to 1. When such a homogenized suspension is sprayed on a surface, it has a tendency to break quickly. Again the initial repellcncy of oil and water appears to give a good surface coating before much of the insecticide penetrates. This phase of the work is being continued. The sur face deposits made as described appear to be heavier than those obtained by direct application of solutions or emulsions. Lindane Vapor I'rehsure in Mix tures with Chlorinated Tekpiienyls. --The lindane vapor pressure in various mixtures of lindane and chlorinated ferphcnyls has been measured (table 1). The lindane was rceryst alii zed from 95 per cent ethanol and had a melting point of 112.5C. The chlorinated Tcrphcnyl was the same product used in the previous tests. The mixtures were prepared by dissolv ing the desired amount of lindane and chlorinated terphcnyls in acetone. Wads of glass wool wrere dipped in the solution, then removed and air-dried for 48 hours. The apparatus consisted of a train having in scries a drying bottle filled with anhydrous calcium sulfate, two gas-satu ration bottles with fritted glass discs through which the air was pulled and packed with the coated glass wool, an Table 1.--Vapor pressure of lindane in mix tures with chlorinated terphenyls at 25 C. Li.viianeClI LOUIN ATED TkUI'HENYIi Ratio Weight Mole Volume OF Saturated Air Sampae (Cubic Feet) 1:0 1:0 1:2 1:1.0 1:5 r.t.o 1:10 1:7.9 2.5 4.0 5.0 6.0 Vapor Pressure (Microns) Meas ured 0.059 .029 .017 .0073 Theo retical ' __ 0.023 .012 .0067 alumina column for adsorbing lindane, a diaphragm-type pump, and a calibrated gas meter. The apparatus was adjusted so that 1 cubic foot of air per hour was pulled through the train. At the comple tion of the run the lindane adsorbed on the alumina was eluted with acetic acid and the lindane determined colorimctricallv (Hornstcin & Sullivan 1953). The vapor pressures were calculated from the results as described by Thomson (1949). The theoretical vapor pressures were calculated on the assumptions that the chlorinated tcrphcnyl had a molecular weight of 3G8 and that the vapor pressure of lindane was proportional to the mole fraction of lindane in the film. Summary.--Lindane residues can' be made to last longer and look better if the lindane is applied in chlorinated tcrphcnyl coatings. The vapor pressure of lindane in these films is lowered, but the fumigat ing action of lindane is not eliminated. A general method of prolonging the residual effectiveness of volatile insecti cides by preparing concentrated solutions in chlorinated polyphenyl film-forming materials has been described. An attempt has also been made to ap ply insecticides on porous surfaces in a manner designed to minimize absorption. DSW 255052 i ' t- L : STLCOPCB4060743 t I! j! ij II fj 1! <i -i 910 Jouknal ok Economic Entomology Vol. J!ffGi., NNoo. G Literature Cited Block, S. S. 1018, Insccliciilal stirfurc cojiliii^'s. Simp nml Simit. Clicm. 24(2): 188--11; (3): 151--3. Campbell, G. A., nml R. R West. 19 Ha. DDT, the new insecticide. A general survey and some possible point applications. Oil & ('(dour (ihem. Assoc. Jour. 27; 211. Campbell, G. A., and R. R West. 1011b. lVrsislenee of DDT in oil-bond water paint. Nature 154: 612. Homstein, I., ami W. N. Sullivan. 1053. Tbe determination of lindane in air, Analyt. Clicm. 25: 496 8. Lindquist, A. W., A. IT. Madden, II. G. Wilson, and K. R Knipling. 1916. DDT as a residual-type treatment for control of houseflies, .limn. Keo.s. Knt. 38; 267. Sullivan, W. N., and 1. llnrnstein. 1953. Chlorinated polyphenyls to improve Jindanc residues. Jouh. Kcon. Knt. 46: 158-9. _ Thomson, G. W. 1919. l'liysical methods of organic chemistry. In A. Weissburger, editor, Technique of Organic Chemistry, lid. 2, Interscience, New York, v. 1, pp. 183-1. Tsao, C. H., W. N. Sullivan, and I. Homstein. A comparison of evaporation rates and toxicity to house flies of lindane and lindane-chlorinated polyphenyl deposits. Joun. Ecorr. Knt. 46: 882-881. Methyl Bromide Fumigation of Soil for Destruction of White-Fringed Beetle Larvae J. I. McClurkin, U.S.D.A., Agr. Res. Adm., Bureau of Entomology and riant Quarantine The '\vliite-fringcd beetle (Grapho- an attempt to improve the* treatment gnathus spR.) is now known to occur in schedules and reduce their i eight Southern States. The larvae arc Methods ok Api'licatu^.--Technical present in theSsoil throughout the year methyl bromide was ammed with a spe (Young & App >f>:)9). Tests for control cially built injector (Easter &Dunn 1942) measures led not only to the use of methyl which delivered a fkfed amount of 7 ml. bromide to fumigalX nursery stock and per injection, licauise the output was not potting soil under confinement (Itawkins adjustable, it was necessary to vary spac- 19:19, Livingston 1940)\but also to the ings betwcejannjcctions in order to apply fumigation of soil areas in\ftu. different ^dosages per square foot. An Use of methyl bromide ud of carbon applicator suitable for injecting small disulhde in quarantine work was first moapdred amounts in rapid succession is approved by this Ilureau in\January djfiieult to make, because of the necessity 1942 (J5EPQ 50:5, 4th rev.) hi for a closed system capable of retaining the basis of tests made at MonnVvi vapors unrler pressure. This system must Alabama (Livingstone & Swank lO also include a quick-acting two-way valve. Tiie approved treatment of soil jlWs Such a valve permits liquid methyl bro and plunging beds provided for ai/fipplr mide to pass from storage into the injector cation of methyl bromide at the rate of' wchamber while its outlet is closed; then the 4.7 ml. per square foot (7 ufl. per 1.5 >nlct is closed and the outlet opened so square feet injected 6 inebe/into tbe soil tl\l lhe charge can escape into the soil at points 15 inches apanir each way. It thrckigh the hollow injection needle. A further provided that Ure fumigated area pressure gauge shows when the chamber should be covered wjMi asphalt builders' is filled\r emptied. Pressures up to 90 paper for 6 days orsoil temperaLures at p.s.i. havcSiKjen used. the 6-inch levcL^ctwecn 45 and 02E., To obviatK the mechanical inconven or for 4 days at temperatures above 62. iences of a cloScd system, volatile liquid It was consj/fcrcd impractical to reduce vehicles having boiling points above nor the pcrmiyfblc minimum soil temperature mal outdoor temperatures were tested. below 45*% for as the 40 boiling point of Aqueous emulsions vvere unsatisfactory, mctlivK bromide was approached this but. certain organic solvents were found funn^ant volatilized less readily and ice suitable. A proprictaryvtroduct contain crystals from soil moisture were formed ing 10 per cent of mcthyl\>romide and 90 fiich obstructed orifices in the injector. percent of ethylenedichlolvde was tested ^Subsequent to this approval, testing was continued first at Gulfport, Mississippi, and later at Burgaw, North Carolina, in 1 Most of tfti* work wu done by G. It. Swank; later he and E. E. Koffen continued this work and made preliminary Uita on the field ute of methyl bromide eolutioaa. DSW 255053 tl of fci sc< eni lh< pr pc hr sp diff sist out tcri out by sire coll ini po mi ge fui wa coi i tes ur: ficl inf sin& The the wcel lish 1 lyp SOOl vati wer tho elaj wer star tion incc off I squ stal spa W&` IMJ.I MW1 STLCOPCB4060744