Document nprrB20O8eOVjo6e6dQEJXzpG

ttract * i Jnsti- l t I ***- * 234-- * CtTt riii (/ **4 In Wtal **Use * H*. i r Mutation Research, 40 (1976) 273--276 Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands Short communication **r A 15ON OF THEUMUTACEMC PROPERTIES O CCiVLOHI^ iNDsMETlfYL CHLORIDE* A.Vi. ANDREWS, E.S. ZAW1STOWSKI and C.R. VALENTINE Frederick Cancer Research Center, Frederick, Maryland St 70J (U.S.A.) (Received December 12th, 1975) (Accepted March 1st, 1976) In developing a screening program for environmental gases using the Ames assay JlJ, we have found that vinyl chloride (CjlljCJ) and methyl chloride (CK}C1) are highly mutagenic. Both gases are industrial chemicals; vinyl chloride in the manufacture of polyvinyl chloride (PVC) and methyl chloride as a refrigerant. Chopra and Sherman [3J have shown the presence of methyl chlo ride in tobacco smoke, thus suggesting that a large portion of our population may be exposed to this gas. The Salmonella typhimurium tester strain TA 1535 which can detect mu tagens causing base pair substitutions, was obtained from Dr. Bruce Ames. The strain was grown in nutrient broth, shaken for 14 h at 37C. and 0.2 ml was then added to molten top agar, with and without 0.5 ml of a 1: 2 dilution of Aroclor 1254-stimuIated liver homogenate (9J. Quintuplicate petri plates con taining Vogel Bonner E medium (SJ were overlayed with this mixture ar.d in cubated inside an anaerobic jar in the 'presence of the test gas. After 72 h at 37*C the revertant colonies were counted using a hand-held tally. To obtain a given percentage of test gas, the anaerobic jar was evacuated to a known pressure. Atmospheric pressure was assumed to be 760 mm of mercury *o that a pressure change of 7.6 mm approximated 1% of the jar volume. Gas was added until the desired pressure change was observed, and the jar was then allowed to fill with room air. The head space of the jar was analyzed after 24-- 48 h by gas chromatography. A gas-tight syringe was used to transfer 5.0 ml of the jar's atmosphere to a sealed 120 ml serum bottle. One ml was then removed from the serum bottle and injected into a Shimadzu GC-4BM gas chromatograph equipped with a flame ionization detector and a 3 foot X 3 mm I.D. glass column packed with 30--100 mesh Porapak Q. The column operating temperatures were 75*C for methyl chloride and 100C for vinyl chloride. The helium carrier gas-flow rate * Rtituch ipon*or*d by lb* NctioaU Ctsm laitllute under codtract do. NOl-C0-23423 wllb Litton Bloarticr. lac.