Chemical world This week
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Barex. The study was successful, says Canada Dry. Vistron is talking with American Can and other major bottle producers about applications other than soft drinks. Also a brewer may test market Barex next year. Barex is now being produced by Ethyl under license from Sohio in a plant at Baton Rouge. The plant went on stream earlier this year but, because of the usual startup problems, has yet to reach target capacity of 1 million pounds per month, Sohio says. (Monsanto makes Lopac materials in Springfield, Mass., and blow-molds Lopac bottles in Bloomfield, Conn.) CONSUMERISM:
Confused as ever Nearly two years after the start of the national debate over phosphate detergents, the ecology- and safety-minded consumer remains as confused as ever. Detergent makers, chemical suppliers, federal officials and others last week confronted Rep. Henry S. Reuss (D.Wis.) and his Subcommittee on Conservation and Natural Resources— where the debate began—and sought to dispel some of the confusion arising from the Nixon Administration's reversal, in effect, on phosphate detergents, cautions on caustics, and continued ban on NTA (sodium nitrilotriacetic acid). Federal officials have backed off from the blanket recommendation by Surgeon General Jesse Steinfeld to use phosphate detergents. Perhaps their advice now can be best summed up as: Most phosphate detergents are reasonably safe but can lead to eutrophication, some alkaline; low- or no-phosphate detergents should be avoided where children are present; and soap can be effective in soft-water areas. At the hearings Colgate-Palmolive and Lever Brothers, but not Procter and Gamble, asked for a federal law to limit phosphorus content to 8.7%, the minimum level for effective cleaning. All three support pre-emption of state and local antiphosphate detergent laws now numbering 71 and which by July 1, 1973, will stop 41 million Americans from using phosphate detergents. NTA, voluntarily removed from U.S. but not Canadian or Swedish detergents, was vigorously defended. An A. D. Little study for P&G, says William C. Krumrei, director of technical government re8 C&EN NOV. 1, 1971
flects: two years later
lations, indicates a low probability of human or environmental hazards at use levels contemplated for the chemical. NTA developer John W. Singer, vice president for W. R. Grace's chemical group, says that a two-year rate feeding study, on which the ban is based, showed: • Except for mammary tumors (to which the rat strain is susceptible), low incidence of other tumors in both controls and test animals. • No significant increase in specific organ tumors nor in total tumors. Criticizing the Surgeon General's statement that the study is inadequate to provide evidence that NTA is not carcinogenic, Dr. Singer points out that no compound has ever been proven not carcinogenic. A number of other chemicals are still in the running as phosphate substitutes. One development viewed with promise by P&G is that of hydrous poly silicates, which can be used in place of highly alkaline sodium metasilicate. PLASTICIZERS:
Pollution suspect Phthalate esters, used in large quantities as plasticizers in plastics, may be significant water pollutants, says Dr. Foster L. Mayer, Jr., of the U.S. Department of the Interior FishPesticide Laboratory, Columbia, Mo. Then again, he adds, they may not. The point is that not much is known about the fate of phthalate compounds in aquatic environments, nor about their effects on aquatic organisms. Thus, there is a need for "a detailed evaluation of
the toxicological effects of phthalate esters," he says. At the American Chemical Society's 27th Midwest Regional Meeting in St. Louis last week, Dr. Mayer cited evidence that phthalate compounds, although not acutely toxic, were, at low chronic concentrations, detrimental to some fish and other aquatic organisms. For example, only 3 p.p.b. of di-2-ethylhexyl phthalate inhibited growth and reproduction of Daphnia magna (a water flea) by 60%. And, Dr. Mayer went on, "food containing phthalate esters produced abortions in guppies [live-bearing fish] and caused large mortalities in zebrafish [egglayers]." The mechanism is poorly understood, but "the offspring of zebrafish usually died in a crescent shape, indicative of altered calcium metabolism." (In an interview, Dr. Mayer points out to C&EN's Ward Worthy that the fish experiments "started with high levels," although within FDA tolerances. Further studies are under way "encompassing only levels found in the environment"—perhaps 200 p.p.b. at most.) Dr. Mayer noted that phthalate ester residues have been detected in waters adjacent to industrial or populous regions of the U.S. and in the fish and other organisms inhabiting those waters. Di-n-butyl phthalate residues have ranged from zero to 0.5 p.p.m.; di-2-ethylhexyl phthalate residues have run as high as 3.2 p.p.m. Phthalates have also been detected in hatchery fish —apparently the result of contamination of their food. About 850 million pounds of phthalate esters were produced in the U.S. in 1970. Mostly used to make plastics—notably polyvinyl chloride—more "plastic," they have an unfortunate tendency to escape. Phthalate residues have also been detected in human blood stored in PVC bags; it has been suggested that such residues may harm those who receive the transfusions of such blood. Dr. Mayer declines to indict phthalate esters as an environmental hazard on the basis of his work. But he notes that they are produced in large quantities and that, somehow, they are entering aquatic ecosystems. More research is essential, he says, "to determine the potential of these compounds to cause adverse effects on aquatic organisms."
