U.S. have shown that pigs grow 50% faster on opaque-2 corn than on nor­mal corn, Trojan says. Even at a premium price, the new hybrid will be less expensive than soybean meal, which is now used as a protein sup­plement for corn. More efficient pro­duction of meat and eggs, due to more economical means of animal produc­tion, will lower total food costs, the firm predicts.

The greatest impact of opaque-2 may be to help reduce malnutrition in protein-deficient areas of the world. This is especially true in Latin Amer­ica and other areas where corn is a basic food, Mr. Keltgen adds. People won't have to change their diet to ob­tain necessary proteins for normal growth. In Guatemalan tests, experi­mental opaque-2 corn was found to be equal to milk in usable protein con­tent.

PHOSPHORIC ACID:

Overabundance in Excess Freeport Sulphur has just started up one of two wet-process phosphoric acid trains at its new phosphate chem­ical complex on the Mississippi River 55 miles above New Orleans. The only product which Freeport will sell out of its $60 million Uncle Sam com­plex is merchant-grade phosphoric acid (54% P 2 0 5 ) except for some surplus sulfuric acid. The company has no plans to produce any other phosphate products at this plant.

This startup creates a huge supply of merchant phosphoric acid for the first time in the Mississippi River area. The company has already engaged customers on long-term contracts and looks to possible spot sales and exports to take an additional share of the out­put.

Freeport's phosphoric acid supply seems to come at an inopportune time in the fertilizer industry: The present oversupply of all phosphate mate­rials will continue to suppress market prices well into 1970 or 1971, fertilizer experts say. Currently phosphoric acid (as 100% P 2 0 5 ) is posted at $160 a ton delivered in the Midwest but considerable discounting is going on in large-volume sales.

During the first seven months of 1968, the production of all phos-phatic fertilizer materials was 2.5 mil­lion tons, down from 2.8 million tons for the same period in 1967. Corre­spondingly, producer stocks have also declined to 563,869 tons at the end of July 1968, down from 710,203 tons at the end of July 1967.

Freeport's complex comprises three 1600 ton-per-day sulfuric acid trains operating in partnership with two Prayon-process phosphoric acid trains.

Excess steam from the contact-process sulfuric acid plants provides 85% of the electrical power requirements of the complex.

The combined capacity of the phos­phoric acid trains is 1.1 million tons a year of merchant-grade acid, which is equivalent to 600,000 tons of plant food. To produce this much acid re­quires 500,000 tons of sulfur or about 12% of Freeport's anticipated 4 million ton 1968 production. Company vice president John Carrington tells C&EN that the company will not be operat­ing its acid trains at capacity for some time. Moreover, he says, the sulfur requirements at the Uncle Sam plant will not cause the company to reduce its sulfur shipments to customers.

Mr. Carrington mentions that the economics of producing phosphoric acid on the Mississippi River work out competitively with those for the Flor­ida producers and Texas Gulf Sul­phur in North Carolina. But, he adds, the company is not planning to inte­grate into other fertilizer operations. The cost of building a fertilizer dis­tribution system with hundreds of farm centers is very great, Mr. Car­rington says.

PESTICIDES:

Mixed Views on DDT The nation's pesticide manufacturers heard some reassuring words about DDT residues last week when they gathered in White Sulphur Springs, W.Va., for their annual meeting. Dr. Paul F. Sand, who coordinates the U.S. Agriculture Department's moni­toring activities told the National Ag­ricultural Chemicals Association that the content of DDT in the soil is not rising to any appreciable extent. But he did caution that in orchards "the residues of some pesticides are rela­tively high and are building up in ex­cess of one year's application."

Accordingly, he advised against

Thomas L. Kimball Asks for ban on hard pesticides

planting crops on land formerly used for orchards pending soil tests for pes­ticide residues. "I can't really explain this buildup," he said, "but it may be that there aren't enough organisms around in orchard soils to degrade the agents." An industry man suggested that fungicide residues could be in­hibiting the soil microbes.

Dr. Sand's report summarizes three years of pilot studies, preparatory to a massive four-year survey that will cover 10,000 sites on cropland and another 5000 on nonagricultural lands all around the country. USDA's pro­gram grew out of a 1963 pesticide re­port issued by the President's Science Advisory Committee and aims to measure the extent of pesticide build­up (or lack of it) in soils, crops, water, sediment, wildlife, and disposal pits.

Dr. Sand bases his conclusion that DDT is not rising in soils on data taken from square mile plots laid out in Grand Forks, N.D., Yuma, Ariz., and Mobile, Ala. While DDT aver­ages rose from 1.65 to 2.23 to 2.31 p.p.m. from 1965 through 1967, he interprets the figures as equivalent, since more DDT was applied in 1966 and 1967.

Meanwhile, the content of two other commonly used pesticides has dropped—dieldrin slightly, from 0.20 to 0.19 p.p.m., and endrin from 0.27 to 0.19 p.p.m.

Dr. Sand's paper came at a meeting which earlier heard National Wildlife Federation director Thomas L. Kim­ball call for a ban on the "hard" pesti­cides such as DDT, dieldrin, aldrin, heptachlor, endrin, lindane, and chlor-dane. Mr. Kimball took the conser­vationist's tack that the durable pes­ticides are accumulating in the en­vironment and are thus slowly wear­ing down the earth's biological re­sources. The more extensive USD A followup study plus a National Acad­emy of Sciences study due for release next spring, plus a federal interagency monitoring program, could help settle the issue of whether pesticides are building up interminably.

S02 REMOVAL:

Method Goes Commercial Efforts to remove sulfur oxides from power plant stack gases are beginning to move into commercial status. In a few days Union Electric plans to start up a limestone injection unit at its Meramec No. 2 power plant in south St. Louis County. Later this year Kansas Power and Light will start up a similar unit at its Lawrence, Kan., station.

In 1969, the Tennessee Valley Au­thority will begin full-scale tests of the limestone injection process at two

12 C&EN SEPT. 30, 1968