by the Occupational Safety & Health Administration regulations, now reduce the residual level of vinyl chloride in certain resins to less than 1 ppm, ac cording to the Society of the Plastics Industry. Such a low initial concentra tion means that the possibility of mi gration of vinyl chloride into food from containers made of such material is nil, the society contends. The group al ready has provided FDA with data to support this position. In proposing the regulations, FDA hints that it may be willing to lend an attentive ear to data of this sort. "The commissioner is aware that the tech nology for reducing the amount of vinyl chloride in vinyl chloride polymers, or eliminating it altogether, is improving rapidly and that major advances not known to FDA may have been made within recent months. Thus, additional classes of food-contact articles may exist for which it can be concluded that there is no reasonable expectation that vinyl chloride would migrate into food," the agency says. Diamond Shamrock, too, indicates that producers "will have no problem in factually supporting a case that this small part of our production [which comes under the regulations] should also receive a clean bill of health" be cause of the much lower residual vinyl chloride levels found in PVC resins today. The company says that it is well along on its goal to reduce the vinyl chloride level of all the material it ships, not only that headed for food packaging uses, to less than 1 ppm. Other companies are planning similar reductions. But the effect of the regulations on PVC markets perhaps is not quite as small as PVC makers would indicate. In one area in particular—plastic bot tles—anticipation of federal regulations has led to a steady shift away from PVC bottles for food products for the past two years. Since 1973, when FDA found that vinyl chloride leached into liquor contained in PVC bottles and the Treasury Department banned sale of liquor in these bottles, packagers have been concerned about the safety of PVC bottles and have been looking for alternative packaging materials. Most nationally sold brands of cooking oil, vinegar, mouthwash, and other materials once packaged in PVC bot tles now are packaged in some other material. Except for the case of liquor, which is sold almost exclusively in glass bot tles, there is no single material that has taken over PVC's food packaging market. Most packagers who were using PVC for its advantages over glass continue to use some type of plastic bottle, packagers claim. Among the materials frequently used are oriented polypropylene and polyester. Acrylonitrile and polycarbonate also have picked up some of the former PVC food pack aging market. Rebecca L. Rawls, C&ENNew York 12
C&EN Sept. 15, 1975
Interest high in plant growth regulators Progress in developing plant growth University of Wisconsin agronomist regulators—particularly those chemi E. S. Oplinger estimates that it costs cals that can increase yields of major $2.50 to $3.00 per acre to apply dinitro food and fiber crops—may lead to one butylphenol to growing corn, and that of the most important quantitative the resulting 10 more bushels of corn gains yet achieved in agriculture. So per acre bring an extra $20 or $25 to say the people who are developing the grower—obviously worthwhile from them. Certainly, interest is high. Ac the grower's standpoint. This year, cording to Dr. Ernest G. Jaworski of about 1 million acres of corn in six states Monsanto, at least 29 major companies were treated with "state labeled" for are actively engaged in research on mulations of the compound. But state such chemicals. registrations are being phased out and, To date, however, progress in bring according to Oplinger, producers and ing plant growth regulators to market formulators of the herbicide aren't in has been modest if not disappointing. terested in seeking federal registration At the recent national meeting of the American Chemical Society, held in Chicago, Jaworski and several other chemists and agronomists gave some details of current research, explained some of the difficulties of "going com mercial," and suggested some possible solutions. Plant growth regulator is, of course, a general term. Dr. A. W. Mitlehner of Uniroyal Chemical describes it as "a substance that releases a plant from its own built-in genetic restrictions." That includes chemicals that cause cuttings to root, chemicals that hasten or retard ripening, chemicals that aid in gather ing or harvesting crops, and others. But it's one particular class—the "yield increasers"—that can make a really significant contribution toward easing the world's food shortages. For example, judicious application of Aerial application of Monsanto's Polaris certain chemicals to sugarcane can in will increase sugar yield of sugarcane crease the yield of sugar 10 or 15%. In some cane fields, that means an extra for a product whose total market would ton or so of sugar per acre, and without amount to only a few thousand pounds a corresponding increase in total bio- per year. That situation is fairly typical of the mass. In fact, notes Dr. Louis G. Nickell of W. R. Grace's Washington re plight of many plant growth regulators. search center, a decade of screening A successful product must provide has turned up "a surprising number" sufficient return to the producer as of chemicals, including herbicides, an well as the user. And unless a producer tibiotics, and even ordinary surfac has solid patent protection, the price tants, that can cause an increase in the he can get for his piddling few tons of accumulation of sugar in sugarcane. compound likely won't justify the con However, there is only one product, siderable expense and trouble of ob Environmental Protection Monsanto's Polaris, with commercial taining registration for that use. Two others, Agency clearance. Thus, if "socially useful" products American Cyanamid's Cycocel and Pennwalt's Ripenthol, are being evalu are to come to market, those who ated under experimental permits; sev would benefit must at least share the eral other products are in the advanced costs of getting them there. For in stance, Mitlehner notes, citrus growers testing stage, Nickell says. Major cereal crops also can benefit asked for and supported the develop from metabolic tinkering. At Purdue, ment of "abscission agents" that, by for example, agronomist A. J. Ohlrogge making it easier to separate fruit from and associates applied tiny amounts of tree, facilitate the mechanical harvest the herbicide dinitrobutylphenol to the ing of citrus crops. Similarly, Nickell foliage of growing corn, two to four points out, the sugar industry has co weeks before tassel emergence. They operated in efforts to commercialize found that the treatment causes the cane-ripening chemicals. In contrast, corn plant to pollinate two or three efforts toward developing plant growth days earlier than it otherwise would. regulators for wheat, corn, and soy The extra few days seem to make a big beans are fragmented. "If all the corn difference. There are more ears and, people got together and furnished $2 because of the longer grain-filling peri million or $3 million to develop [plant od, the ears are bigger. Overall, the in growth regulators] for corn," Nickell comments, "they would be developed."Ε crease is on the order of 5 to 10%.
