Pesticides and

Until It was banned in the United States in 1984 1 2 di bromoethane (ethylene dibromide orEDB)waspro duced on a large scale for use as a pesticide and soil fumigant... 

Heico Chemicals is the only producer of acetamide in the United States. Small amounts are imported from Europe and Asia. It is shipped in 32-L (35-gal) dmms weighing about 80 kg. Acetamide appears to have a wide spectmm of appHcations. It suppresses acid buildup in printing inks, lacquers, explosives, and perfumes. It is a mild moisturi2er and is used as a softener for leather, textiles, paper, and certain plastics. It finds some appHcations in the synthesis of pharmaceuticals, pesticides, and antioxidants for plastics. 

Sprays. Aerosol spray emulsions are of the water-in-oil type. The preferred propellant is a hydrocarbon or mixed hydrocarbon—hydrofluorocarbon. About 25 to 30% propellent, miscible with the oil, remains in the external phase of the emulsion. When this system is dispensed, the propellant vaporizes, leaving behind droplets of the w/o emulsion (Fig. 2b). A vapor tap valve, which tends to produce finely dispersed particles, is employed. Because the propellant and the product concentrate tend to separate on standing, products formulated using this system, such as pesticides and room deodorants, must be shaken before use. 

Herbicides are also sometimes classified according to mode of action, selectivity, registered uses, and toxicity. The ever-increasing importance of herbicides and other pesticides and agrochemicals to a wide range of users, regulators, and researchers has led to the development of multiple and extensive computer databases. The primary database resources contain collected information relevant to herbicides, and numerous resource pubHcations are available to those needing information on the various aspects of herbicides (2). 

U.S. EPA, National Pesticide Survey Phased Report, Offiice of Water, Office of Pesticides and Toxic Substances, EPA 570/9-90-015, U.S. Govt. Printing Office, Washington, D.C., 1990. 

Cyclic Hydrocarbons. The cyclic hydrocarbon intermediates are derived principally from petroleum and natural gas, though small amounts are derived from coal. Most cycHc intermediates are used in the manufacture of more advanced synthetic organic chemicals and finished products such as dyes, medicinal chemicals, elastomers, pesticides, and plastics and resins. Table 6 details the production and sales of cycHc intermediates in 1991. Benzene (qv) is the largest volume aromatic compound used in the chemical industry. It is extracted from catalytic reformates in refineries, and is produced by the dealkylation of toluene (qv) (see also BTX Processing). 

ISI is available in hard copy and electronically at EPA s headquarters and regional Hbraries, and through the National Technical Information Service (NTIS). The electronic form may be installed on IBM PC-compatible computers or placed on local area networks, and mn under Microsoft WINDOWS or WordPerfect s Library program. The Macintosh version is no longer available. The 1993 update will include the ISI hardcopy, PC disks, and the PC system user manual. EPA also pubHshes ACCESS EPA, which provides sources of information, databases, and pubHcations within the EPA. Chapter 5 of that pubhcation includes important environmental databases in air and soHd waste, pesticides and toxic substances, water, and cross-program (110). EPA also provides databases accessible through EPA Hbraries, which describe the private EPA and commercial databases available to Hbrary users (111). 

Naphthalenesulfonic acid can be converted to l-naphthalenethiol/T25 -J6 - by reduction of the related sulfonyl chloride this product has some utihty as a dye intermediate, and is converted by reaction with alkyl isocyanates to 3 -naphthyl-A/-alkylthiocarbamates, which have pesticidal and herbicidal... 

Pesticides and Safety of Fruits and Uegetables, CAST No. 1990-1, Council for Agricultural Science and Technology, Ames, Iowa, Dec. 1990,15 pp. 

Uses. Isoquinoline and isoquinoline derivatives are usehil as corrosion inhibitors, antioxidants, pesticides, and catalysts. They are used in plating baths and misceUaneous appHcations, such as in photography, polymers, and azo dyes (qv). Numerous derivatives have been prepared and evaluated as pharmaceuticals. Isoquinoline is a main component in quinoline stiH residue bases, which are sold as corrosion inhibitors and acid inhibitors for pickling iron and steel. 

Toxic Substances Control Act, Chemical Substances Inventory further information can be obtained from Industry Assistance Office, Pesticides and Toxic Substances, Environmental Protection Agency, Washington, D.C. 

In addition to conventional pesticides such as insecticides, herbicides, and fungicides, there are other chemicals classified as pesticides and regulated under FIFRA. These chemicals include wood preservatives, disinfectants (excluding chlorine), and sulfur. In the United States these chemicals have aimual usage of about 500,000 t, which is equal to conventional pesticides. 

The rate and extent of pesticide metaboHsm can vary dramatically, depending on chemical stmcture, the number of specific pesticide-degrading microorganisms present and their affinity for the pesticide, and environmental parameters. The extent of metaboHsm can vary from relatively minor transformations which do not significantly alter the chemical or toxicological properties of the pesticide, to mineralisation, ie, degradation to CO2, H2O, NH" 4, Cf, etc. The rate of metaboHsm can vary from extremely slow (half-life of years) to rapid (half-life of days). 

The documented occurrence of pesticides in surface water is indicative that mnoff is an important pathway for transport of pesticide away from the site of appHcation. An estimated 160 t of atra2ine, 71 t of sima2ine, 56 t of metolachlor, and 18 t of alachlor enter the Gulf of Mexico from the Mississippi River annually as the result of mnoff (47). Field appHcation of pesticides inevitably leads to pesticide contamination of surface mnoff water unless mnoff does not occur while pesticide residues remain on the surface of the soil. The amount of pesticides transported in a field in mnoff varies from site to site. It is controUed by the timing of mnoff events, pesticide formulation, physical—chemical properties of the pesticide, and properties of the soil surface (48). Under worst-case conditions, 10% or more of the appHed pesticide can leave the edge of the field where it was appHed. 

Sorption. Most organics are sorbed to a very small degree on the biofloc, ie, < 2 percent. Exceptions are the nondegradable pesticide Lindane, other pesticides, and PCBs. Heavy metals will complex with the ceU wall and precipitate within the floe. Metal accumulation will increase with increasing sludge age. 

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