tate, methyl stearate, diethyl hexyl phthalate, C15 terpineol, and methyl myristate. Although, of these compounds, only the phthalate ester is a synthetic, the majority of all the compounds identified were of synthetic origin, and many have been identified as toxic or carcinogenic, EPA notes. In base-extfactable fractions, 89 compounds were identified. Most frequent were diethyl hexyl phthalate, dibutyl phthalate, C15 terpineol, and C10 terpineol. Of these, the two phthalate esters are synthetic organics. Purgeable organic compounds in the samples numbered 81, most of them halogenated hydrocarbons from Ci to C6. Most frequently appearing were chloroform, trichloroethylene, tetrachloroethylene, 1,2-dichloromethane, toluene, and bromodichloromethane. EPA attaches significance to the presence of chloroform and many of the other chlorinated and brominated hydrocarbons in almost every sample, but at levels below 1 ppb. The widespread occurrence of the compounds, suspected carcinogens or known to be toxic, emphasizes the need for further study of their origin and impact, EPA points out. •
data before deciding whether to change xylitol regulation. Xylitol currently is marketed in the U.S. in only one product—Orbit, a chewing gum manufactured by Wrigley. The company does not plan to make any changes in its gum or in the way it is advertised because of these findings. "We don't feel these preliminary feeding tests indicate anything dangerous in xylitol," says assistant vice president David Sloane. He points out that xylitol, a sugar alcohol, is a natural product that is synthesized by many animals, including humans, in the process of carbohydrate metabolism. Humans synthesize from 5 to 15 grams of xylitol a day. The level of xylitol given to the test animals is equivalent to chewing 200,000 sticks of gum a year, Sloane says. A pretty good gum chewer, he adds, might chew several hundred sticks a year. For the moment, Hoffmann-La Roche, too, is making no changes in its plans to market xylitol in the U.S. Xyrofin plans to build a plant at Savanna, 111., to make 10,000 tons a year of xylitol from corncobs. •
Long-chain alcohol boosts crop yields Field trials completed this summer at Michigan State University have verified that sprays containing a tiny amount of a naturally occurring alcohol, triacontanol, can increase the yields of a wide variety of commercial crops up to 24%. The substance thus stands to become an important supplement to increasingly expensive nitrogen fertilizer. Dr. Stanley K. Ries, an MSU horticulturist, last week described his work to science reporters gathered at Rockefeller University for the 15th annual meeting of the Council for the Advancement of Science Writing. Triacontanol, CH3(CH2)28CH2OH, is ubiquitous in the plant world, he explains; it occurs in leaf waxes, in honey and beeswax, and even in potatoes and apples. In fact, it is commonly present in soil. Even so, adding just a tiny bit more triacontanol to a field—at rates of only a few milligrams per acre—causes an immediate spurt in plant growth.
Xylitol causes some cancers in mice Xylitol, a sucrose substitute made from birch trees that has been touted for its tooth decay preventive properties, apparently has caused some cancers in laboratory animals. Preliminary findings from two-year chronic toxicity studies show an increase in urinary bladder stones in male mice fed xylitol in doses of 10% and 20% of their total diet. Some of the mice that developed bladder stones also had bladder inflammation and benign and malignant tumors. Female mice developed no unusual symptoms, and neither did male mice fed xylitol as 2% of their diet. The studies are being conducted by Huntingdon Research Centre in England for Xyrofin, a joint venture formed by Hoffmann-La Roche and Finnish Sugar Co. to produce ond market xylitol. In addition to mice, studies are being conducted on rats and dogs. Neither of these animals shows bladder changes associated with xylitol consumption, but rats fed xylitol as 20% of their diet show an increased incidence of adrenal gland tumors. Hoffmann-La Roche turned the preliminary test data over to the Food & Drug Administration earlier this month. FDA is reviewing the test
Highway test to use sulfur in pavement Asphalt and sulfur here feed into a portable unit to produce binder that will be used in a portion of an Alberta highway. The largest test yet of sulfur-asphalt paving, a 6-mile strip is being put down near Rocky Mountain House. The project is supported primarily by the Sulphur Development Institute of Canada (SUDIC), with a contribution from Gulf Oil Canada Ltd. Two independently developed sulfur/asphalt emulsion pavements will be tested—the Pronk process of R. M. Hardy & Assoc, and that of Gulf Oil Canada. The two processes differ slightly in process but produce essentially the same product. Sulfur is emulsified in asphalt, replacing up to 4 0 % of the asphalt in the binder, the binder then being used with regular aggregate to form the paving material. The Pronk portion of the trial uses a separate, portable unit (above) to produce the binder. SUDIC estimates that material costs for the trial are about 2 5 % less than for a conventional mix. And Alberta is looking for a way to use its large stockpiles of by-product sulfur from natural gas purification.
Nov. 21, 1977C&EN
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