Document rBjeBQQEZOaRqEdkvVZVjY97e

Do S3- SC-3 <*7 Effects of Polyvinyl Chloride Ingestion by Dogs William S. Johnson, DVM, MS, MPH, and Robert E. SchmidttDVM nt= ycB Ut MmS tCfiJmkiU, Mt. JUN2 71978 ~( SUMMARY Polyvinyl chloride (pvc) acrylic thermoplastic sheeting was fed to 6 dogs to determine whether ingestion during periods of normal transit of military working dogs would be toxic and thus affect the safety of this ma terial for construction of shipping containers. The test dogs were fed fvc acrylic (0.125 gfkg of body weight; by gelatin capsule) twice each day for 5 days: for 2 dogs, the test material was in a shredded form; `for 2 dogs, the material was diced; and for 2 dogs, it was powdered. Two other dogs were used as controls. Dogs were observed for clinical signs, and feed consumption and body weights were recorded. Blood and urine samples were examined. All animals were necropsled approxi mately 10 days after the feeding was Stopped. Clinical or pathologic indication of a toxic effect of fvc was not seen within the time limits ofthe study. Information on die effects ofpoly vinyl chloride (pvc) acrylic material ingested by military working dogs was needed, since construction of shipping containers with thiB mate rial was under consideration. Review of Literature Vinyl chloride toxicity in animals has been reviewed.' The primary concern of most investigations has been the possible carcinogenesis and other toxic reactions Received for publication Dec 3,1976. From the Operaling Location AA, US Air Form Occupational and Environmental Health Labora tory at Kelly Air Feme Barn, Tx (Johnson); and from the Comparative Pathology Branch. Valerinary Science* Division, US Air Force School of Aer ospace Medicine. Brooks Air Force Bass, Tx (Schmidt). Address reprint request* I* Dr. Schmidt. INFORMATION PERVICSS. from exposure to the airborne monomer ofvinyl chloride which is used as an aero Test Period--The 2 control animals were fed a normal diet, and the 6 test sol propellant in a variety of household and cosmetic products. Vinyl chloride gas was actively toxic for mice, rats, guinea pigs, and rabbits, with congestion of in ternal organs being the predominant le dogs were given pvc acrylic <0.125 g/kg of body weight; in 3 forms, by gelatin cap sule) twice each day for 5 days. Two of these animals were fed the fvc in the form of 6-mm squares of test material sion.* ' Vinyl chloride has a local irritating effect on skin and mucous membranes; however, chronic feeding (2 years) of 1.5 to 14% vinyl chloride-vinyl acetate copol ymer to rats produced no observable toxic effects.* (diced); 2 animals were fed test material shredded on a milling machine, and 2 animals were fed test material which had been ground into powder. Dogs were dosed at 8:00 am end 4:00 pu and fed a commercial dog food* at 12 noon daily. Drinking water was provided Severe fibroblastic reactions in mus cle tissue were produced by implantation of vinyl chloride plastics'in rabbits and guinea pigs.3 Determination was not made, how free choice at all times. Dogs were observed each day for clini cal signs, and body weight and feed con sumption were recorded. Blood and urine samples were obtained 2 days apart dur ever, whether the reaction was produced ing this phase, and values for hemato by monomer, polymer, plasticiser, or logic examinations, serum alanine ami other additives. notransferase, serum blood urea nitro Results of tissue culture experiments gen, and routine urinalyses were ob in vitro indicated a toxic potential occurs tained. from materials migrating from pvc.4 Tis sue culture medium exposed to pvc tub ing caused chicken embryo heart cells to show blistering and granularity, and caused the heart to stop beating.* An aqueous extract offvc resin given orally to rats retarded weight gains and decreased blood catalase activity.4 The polymers of vinyl chloride con tain unreacted monomer and other addi tives.1 However, to date, no extensive re Postfoeding Period --The feeding trial was terminated at the end of 5 days. Since clinical signs were not seen during the feeding period, dogs were continued under observation for 10 days and then were euthanatized and necropsied. Blocks of tissue were fixed in 10% buffered formalin, embedded in paraffin, cut at 6 jun, and stained with hematoxy lin and eosin. search has been accomplished to deter mine the oncogenic and toxicologic poten ^Results tials ofplasticizers, antioxidants, and un reacted monomers contained in fvc /Y With the exception of occasional otherwise deemed as safe. Zsoft feces, abnormal clinical signs (.were not seen. The test material was Materials and Methods _ observed to pass through the diges tive gystem of all animals un Test Animals--Eight dogs were used; they were active, adult males of uniform size, outwardly healthy, and free ofexter nal parasites. changed. Results of hematologic ex amination, blood chemical analyses, and urinalyses were within normal values in all dogs throughout the Tent Phones--Pretest Holding and Acclimation --All animals selected for the experiment were held in the test area for 7 days after clinical examination to accli mate them to the environment and feed ing regimen. Test animals were treated for minor clinical abnormalities or nema tode infestations. Results ofblood, urine, and focal examinations were within nor mal limits. testing periods. Gross and micro scopic lesions attributable to the test material were not seen. Discussion Incompatibilities resulting from short-term ingestion of pvc acrylic `Purina Laboratory Canine/Dog Chow, Ral ston Purina Company, St Louii. Mo. November, 1977 w 1891 AP00007628 ''-I- I thermoplastic were not seen in the dogs, and lesions attributable to this compound were not discovered. There was apparently little absorp tion, and there was no evidence of hematogenous dissemination of par ticles, as has been previously re ported.' This may be due to differ ence in particle size, total amount, or some other difference in experimen tal method. There is now no rationale to indicate that serious problems would evolve in dogs that might in- est i>vc acrylic thermoplastic used g1 the construction of shipping con tainers for short-time transit of dogs. Ah attempt was not made to estab lish the statistical validity of the re sults, since the goal was to obtain an overview of any incompatabilities that would evolve as a result of inges tion of this material. References 1. BischolT P; Organic polymer bioeompatability and toxicology. Clin them 18:869894, 1972. 2. De H&an RL: Toxicity oftissue culture media exposed to polyvinyl chloride plastic. Nature {New Biol} 231:: 85-86,1971. S. Cues* WL, Haberman S: Toxicity pro. files of vinyl and polyolednic plastics and their additives. In Proceedings. Tech ConfSoe Plastics Eng, New York, NY, 1967. pp 15-23. 4. Gums WL, Haberman S, Rowan DF, Bower RK, Autian J: Characterization o*~ubtie toxicity ofcertain plastic components used in manufacture of polyvinyls. Am J Hosp Pkarm 24; 495-496, 1967. 5. Prodon L, Suciu I. Pislarv V, Ifea E, Posco L: Experimental acute toxicity of vinyl chloride fmonochlorolhene). Anri, NY Aco<i Set 246: 154-156. 1975. 6. Radeva M, Dinoeva S: Investigation of the blastomogenic action ofpolyvinyl chloride resin used in the food industry. Onhologiia. Inf Biul Prllothein 3 : 24, 1970. 7. Schottek W: Zur toxikologie des v>. nyichlorids. Chem Technol. 21:708-711,1969. 8. Smyth HF, Jr, Weil CS: Chronic oral toxicity to rata of a vinyl chloride-vinyl ace* tate copolymer. Toxicol Appl Pharmacol 9:502-504, 1966. S. Yolkeimer G: Hematogenous dissemi nation of ingested polyvinyl chloride partides. Ann NY Acad Set 246: 165-171,1975. 1892 Am J Vet Res. Vol 38, No AP00007629