Pesticides solid formulations

In 1974 Midwest Research Institute operated a pilot-scale multiple chamber incinerator to evaluate for EPA the operational variables for pesticide incineration (8). The system included a. pilot-scale incinerator, a three-stage scrubber system, and a scrubber water treatment system. Nine pesticides (aldrin, atrazine, captan, DDT, malathion, mirex, picloram, toxaphene, and zineb) in 15 liquid and solid formulations were studied. Destruction efficiencies generally exceeded 99.99% over a range of temperatures and retention times ( 950 to 1100°C, 1.2 to 6 s, and 80 to 160% excess air). This study also documented the generation of measurable quantities of cyanide in the incinerator off-gas during the incineration of organonitrogen pesticides. 

Chlorinated camphene (loxaphene [CAS 8001-35-2]) Moderately irritating upon direct contact. A CNS convulsant. Acute symptoms in-clude nausea, confusion, tremors, and convulsions. Well absorbed by skin. Potentiai iiverand kidney injury. See also p 161. 0.5 mg/m , S,A3 200 mg/m Waxy amber-colored solid. Formulations vary In appearance. Turpentine-like odor. Vapor pressure is about 0.3 mm Hg at 20°C (68°F). Pesticide use banned In the US since 1990. 

Controlled-release solid formulations of selected volatile organophosphorus pesticides (malathion, DDVP, sumithion, chlorpyriphos, and sulprofos) were studied by Szente [33]. These solid formulations exhibited negligible vapor pressure and preserved their entrapped pesticide content even at elevated temperature. Malathion and chlorpyriphos formulations showed increased physical stability, and resulted in an effective masking of the unpleasant smell while the complex formulations existed as dry solid. Sulfluramid is an expensive insecticide that is lost by volatilization, but complexation to j8-CyD reduced the loss [21]. 

Polymer uses other than polymeric or slow-release pesticides have also been developed. Polymers have been used for the control of flocculation of traditional pesticide suspension formulations. This is particularly true in the preparation of concentrated suspensions, those in excess of 0.4 volume fractions of the solid.Surface active agents, of the ionic or nonionic types, can be used, but they suffer for various reasons and are not able to prevent flocculation under all conditions. 

There are two primary reasons for using any mineral in a pesticide product formulation, and a limited number of subsidiary reasons. The two overwhelming uses of minerals are as a carrier or as a solid diluent. Regardless of the means by which the end-use product is applied to a target site by a grower or commercial applicator, products utilizing minerals as carrier or solid diluent will be sold in a dry form. 

Flowables utilize solid active ingredients, or liquid actives absorbed onto a solid carrier, but are presented to the end user as a liquid. Micronized particles of active ingredient are suspended in a liquid carrier. Water is almost invariably the carrier of choice, since it is much less expensive than any organic liquid. As noted above the problem to be overcome with this formulation is the density difference between suspended solids and the fluid medimn. The specific gravity of pesticide solids is typically on the order of 1.2, resulting in rapid settling of solids in water. 

A solvent free, fast and environmentally friendly near infrared-based methodology was developed for the determination and quality control of 11 pesticides in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples inside glass vials and a multivariate calibration model to determine the active principle concentration in agrochemicals. The proposed PLS model was made using 11 known commercial and 22 doped samples (11 under and 11 over dosed) for calibration and 22 different formulations as the validation set. For Buprofezin, Chlorsulfuron, Cyromazine, Daminozide, Diuron and Iprodione determination, the information in the spectral range between 1618 and 2630 nm of the reflectance spectra was employed. On the other hand, for Bensulfuron, Fenoxycarb, Metalaxyl, Procymidone and Tricyclazole determination, the first order derivative spectra in the range between 1618 and 2630 nm was used. In both cases, a linear remove correction was applied. Mean accuracy errors between 0.5 and 3.1% were obtained for the validation set. 

Mancozeb is a dithiocarbamate pesticide with a very low solubility in organic and inorganic solvent. In this work we have developed a solvent free, accurate and fast photoacoustic FTIR-based methodology for Mancozeb determination in commercial fungicides. The proposed procedure was based on the direct measurement of the solid samples in the middle infrared region using a photoacoustic detector. A multivariate calibration approach based on the use of partial least squares (PLS) was employed to determine the pesticide content in commercially available formulations. 

The main purpose of pesticide formulation is to manufacture a product that has optimum biological efficiency, is convenient to use, and minimizes environmental impacts. The active ingredients are mixed with solvents, adjuvants (boosters), and fillers as necessary to achieve the desired formulation. The types of formulations include wettable powders, soluble concentrates, emulsion concentrates, oil-in-water emulsions, suspension concentrates, suspoemulsions, water-dispersible granules, dry granules, and controlled release, in which the active ingredient is released into the environment from a polymeric carrier, binder, absorbent, or encapsulant at a slow and effective rate. The formulation steps may generate air emissions, liquid effluents, and solid wastes. 

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

In a similar study, Versar, Inc., in 1974-1975, demonstrated for EPA that DDT and 2,4,5-T formulations were destroyed in a municipal sewage sludge incinerator in Palo Alto, California (5). The pesticides were added to sludge (which contained 20% by weight of solids) to form a mixture that was 2 to 5% by weight in pesticides. Destruction efficiencies ranged from 99.95 to 99.99% for an average hearth temperature from 600 to 690°C and an afterburner temperature from 650 to 660°C. 

Hwang, B.H. and M.R. Lee. 2000. Solid-phase microextraction for organochlorine pesticide residues analysis in Chinese herbal formulations. J. Chromatogr. A 898 245-256. 

Many industrial and consumer products are formulated as emulsions including numerous surface coatings (Chapter 12), foods, pesticides and herbicides (Chapter 13), pharmaceutical products (Chapter 14), and personal care products such as creams and lotions (Chapter 15). Some emulsions are made to reduce viscosity so that an oil can be made to flow. Emulsions of asphalt, a semi-solid variety of bitumen dispersed in water, are formulated to be both less viscous than the original... 

Uses Bendiocarb is an odorless, white crystalline solid. It is stable under normal temperatures and pressures, but should not be mixed with alkaline preparations. Thermal decomposition products may include toxic oxides of nitrogen. It is noncorrosive. Formulations of bendiocarb are classified as general use pesticides (GUP), with the exception of Turcam and Turcam 2.5 G, which are classified as restricted use pesticides (RUP). In view of this, the chemical should be purchased and used only by certified and trained applicators. 

The chemistry of the decomposition of Guthion in the solid state has been studied rather thoroughly (4). On the other hand, decomposition in solution has received little attention, at least to the extent that mechanisms are well understood. The mode by which epichlorohydrin enters into this reaction is at present even less understood. The rationale for this study, of course, was to investigate useful and economic pesticidal formulations. Many of the questions that remain unanswered are of academic interest and will be pursued as time permits. An understanding of the decomposition mechanisms of a toxicant and those parameters that effect the decomposition is essential for the production of superior pesticidal formulations. 

Su oemulsions are defined as a mixture of a dispersed solid phase and an emulsified oil phase in water as the continuous or bulk phase. The solid phase is a solid, water insoluble active ingredient, the oil phase a liquid pesticide in pure form or dissolved in a water insoluble solvent. The oil phase can sometimes also be an oil or adjuvant. Suspoemulsions are a relatively new formulation type as becomes evident by the fact that a FAO specification was established only as late as 1997. At the same time specific evaluation methods were officially published (CIPAC MT 180) [2]. 

Pesticides, then, are formulated into many usable forms for satisfactory storage, for effective application, for safety to the applicator and the environment, for ease of application with readily available equipment, and for economy. These goals are not always early accomplished, due to the chemical and physical characteristics of the technical grade pesticide. For example, some materials in their "raw" or technical condition are liquids, others solids some are stable to air and sunlight, whereas others are not some are volatile, others are not some are water soluble, some oil soluble, and others may be insoluble in either water or oil. These characteristics pose problems to the formulator since the final formulated product must meet the standards of acceptability by the user. 

Pesticides are more extensively applied as liquids than as solids. Even some dry formulations, such as wettable powders, are diluted or suspended in a liquid before being applied. Different formulations present different hazards to the applicator. Figure 4.2 describes the hazards of various formulations. 

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