The Formulation of Pesticides

Seaman, D. 1990. "Trends in the Formulation of Pesticides An Overview." Pesticide Science 29 437-49. 

Pesticides are substances that repel, kill, or otherwise control unwanted animals or plants. Examples include insecticides, fungicides, and herbicides. The formulation of pesticides is significant in terms of product stability and product perfor-... 

Furmidge, G.G.L. The application of flying-spot scanning to particle size analysis in the formulation of pesticides. Analyst. 1963, 88, 686. 

OTHER COMMENTS used in the formulation of pesticides used in the manufacture of flea powders, fly sprays, and moth-proofing agents used as an application on agricultural crops and livestock. 

OTHER COMMENTS used mainly as an immediate action rodenticide use in the formulation of pesticides used for the elimination of predators. 

Pesticides are substances that repel, kill or otherwise control unwanted animals or plants. Examples include insecticides, fungicides and herbicides. The formulation of pesticides is significant in terms of product stability and product performance. The current trend in crop protection is towards products that are more potent, safer to user, having less impact on the environment, more convenient to use and improved efficiency of the apphed product [85]. In the case of sprayed products, colloid and interface science impacts all aspects of apphcation. First, spray droplets impact the leaf surface, creating a fohar deposit from which the pesticide moves into the leaf or contacts the pest (see Figure 13.7) [85]. The spray pattern is influenced by the applicator nozzle hydrodynamics, the physical properties of the spray fluid and the movement of sprayer vehicle. 

The lower dynamic surface tensions appear to aid the formation of larger droplets during atomization of the pesticide. This physical effect reduces spray drift. The use of surfactants that rapidly move to the interfaces produces lower dynamic surface tensions over the time frame of droplet generation for the test nozzles (5-50 ms). These surfactants are often the lower-molecular weight anionic and nonionic surfactants commonly used in the formulation of pesticides. 

Pesticide Dispersants. Modified lignosulfates and lignosulfonates derived from kraft lignins are used in the formulation of pesticides. In wettable powders, suspension concentrates, and water-dispersible granules, they act as dispersants and prevent sedimentation. They also act as binders in the production of granular pesticides. Typical usage levels in these types of products range from 2 to 10%. 

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. 

MisceUaneous uses include extraction and purification of penicillin, alkaloids, vitamins, and flavors, and as an intermediate in the preparation of dyes and pesticides. Chloroform has also been used as a fumigant and insecticide, in the formulation of cough symps, toothpastes, liniments, and toothache preparations. These latter uses were banned by the FDA in 1976 (38). 

Pesticides. Many pesticides are highly concentrated and are in a physical form requiring further treatment to permit effective appHcation. Typically carriers or diluents are used (see Insectcontroltechnology). Although these materials are usually considered inert, they have a vital bearing on the potency and efficiency of the dust or spray because the carrier may consist of up to 99% of the final formulation. The physical properties of the carrier or diluent are of great importance in the uniform dispersion, the retention of pesticide by the plant, and in the preservation of the toxicity of the pesticide. The carrier must not, for example, serve as a catalyst for any reaction of the pesticide that would alter its potency. 

The full extent of the toxicity of pesticides to aquatic life is not known. Although chronic toxicity testing is required for new substances, little is known about the long-term effects of older pesticides. Also, very little is known about the toxicity and occurrence of the products formed when pesticides break down (metabolites) or the many non-pesticidal additives (co-formulants and adjuvants) used in pesticide formulations. However, the future is looking brighter. New modelling techniques, EQS development, and the involvement of the NRA in the pesticide registration process, coupled with the development of newer, less persistent pesticides with lower dose rates, all should help to reduce the risk of pesticide pollution. 

In occupational settings, exposure to endosulfan is mainly via the dermal and inhalation routes. Although workers involved in the manufacture and formulation of pesticide products containing endosulfan are potentially exposed to high concentrations of the compound, actual exposure is probably limited by the use of engineering controls and personal protection equipment. The highest documented dermal and inhalation exposures have been reported for agricultural workers involved in the spray... 

Pesticides may enter the atmosphere during spray applications of the formulated product, by volatilization, through management practices, via wind-distributed soil particles containing absorbed pesticides, etc. Several analytical methods have been reported over the last 30 years for the determination of pesticides in air, and all involve the passage of known volumes of air for a pre-defined time period through an adsorbent material to trap the desired analytes. These analytes are then extracted, concentrated, and analyzed. A few analytical methods have been reported for the determination of triazine compounds in air in the last decade. 

Herbicide 2,4,5-T was not alone. We do not know the fate of the toxic dioxins that spread throughout the USSR in the formulations of different pesticides 2,4,5-trichlorophenol, 2,4,5-trichlorophenol copper salts, 2,4-D, pentachlorphenol, propanile, and many other formulations made up of various components. 

Code for the Storage of Liquid and Solid Oxidizers Code for the Storage of Organic Peroxide Formulations Code for the Storage of Pesticides... 

From the anionic surfactants (Table 1.1) the most relevant is LAS with an annual global production volume of more than 3 X 1061 in 2001. LAS has a wide application because of its excellent detersive properties and cost-performance ratio. Commercial LAS is applied mainly in the formulation of powder and liquid laundry detergents. The calcium salts are used as an emulsifier in pesticide formulations their amine salts are used in dry cleaning and as degreasing agents in the metal industry [14]. 

Those degradation products which have been identified in our investigations are 1-naphthol from carbaryl, 2,4-D acid and 2,4-dichlorophenol from 2,4-D ester, 2-chloro-2, 6 -diethylacetanilide from alachlor, o,o,oe-trifluro-2-nitro-6-amino-N,N-dipropyl-p-tolu-idine and o,o,o-trifluro-2,6-diamino-N,N-dipropyl-p-toluidine from trifluralin, and a variety of phenols and acids from the degradation of the aromatic solvents used in the formulation of the liquid pesticides as emulsifiable concentrates (41,42). 

---