Pesticides, formulation types

From the perspective of protective clothing selection and chemical resistance, the pesticide formulation types may be more generally categorized as ... 

Therefore, pesticide formulations are most usefully categorized by formulation type rather than by mineral class. In Table 1 minerals are placed according to the pesticide formulation type and use with which they are most commonly associated. Keep in mind, however, that this scheme represents general use patterns. The variety of pesticide product end-use patterns is... 

This is the only liquid pesticide formulation type in which minerals play a significant part. The quantity of mineral used is small, but the physical... 

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. 

Based on the patch method to assess worker or re-entry exposure, researchers have developed a database, which may be used to estimate exposure. Each patch from an individual in a study can be entered into the database separately, the residue data from patches from various body areas can be summed to yield a whole-body exposure number, and the data may be sorted as to worker tasks, equipment used, protective clothing worn, formulation types and other parameters. This is the basis for the currently used Pesticide Handlers Data Base (PHED), which was developed through a joint effort in the 1980s of CropLife America [formerly known as American Crop Protection Association (ACPA) and National Agricultural Chemicals Association (NACA)], the Environmental Protection Agency (ERA) and Health Canada. " The PHED is discussed in detail in another article in this book. 

Tpo understand the physical and colloidal chemical aspects of pesticidal formulations research, one must first understand the objectives of the formulations chemist in his work. Simply speaking, the formulations chemist must take the pure organic chemical pesticide and put it in a usable form for field use. These forms include wettable powders, emulsifiable concentrates, dusts, granules, water-soluble concentrates, flowables, and an aerosol, to name a few types of concentrates. The formulations chemist desires to put together a formulation that (1) is easy and eco-... 

Pesticide formulation science Is a very broad field because It must deal with formulation development, production and storage (1-A) as well as the Interaction of the pesticide with plants. Insects, mammals, soil, air and water ( ). Pesticide formulations can be classified Into the following types ... 

Use of Computers for Evaluation and Optimization of Formulations Computers are being used very effectively for evaluation and optimization of pesticide formulations. Computer assisted optimization of formulation physical and biological properties and cost (responses) vs. type and concentration of ingredients (independent variables) can be divided into three parts. 

Indoor exposure assessments can be more complex than outdoor assessments. The indoor assessments are often complicated by the fact that pesticide application methods and their placement within the indoor environments are very diverse and include, for example, crack and crevice treatment, carpet treatment, room loggers, moth repellents, residual termiticides, disinfectants and pet products. This diversity also means that potential human contact with the residues may range from a low probability (crack and crevice treatment) to a higher probability (indoor broadcast treatment such as an indoor total release logger) because of the nature of the application and the variability in activities that may bring individuals in contact with treated areas. Furthermore, the varied characteristics of the source (e.g. formulation type, application methods, room of application and duration of emission) and the indoor residential environment (e.g. room size, air exchange rates, temperature and types of surfaces, such as carpet, upholstery, vinyl, etc.) significantly influence exposure pofenfial. 

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]. 

An adjuvant or additive is a chemical added to a pesticide to increase its effectiveness or to reduce its phytotoxicity or drift. Adjuvants are used most extensively in products designed for foliar applications. Most pesticide formulations already contain adjuvants. Several different types of adjuvants are ... 

Becanse most pesticide formulations are proprietary and because until recently their components other than the active ingredient were not considered important from a health perspective, there is little published information available on the types and concentrations of organic solvents in pesticide for-mnlations. However, information from the literature and discussions with persons knowledgeable on pesticide formulations provides some insight into the identity of the solvents. Categorized according to functional group type, solvents that are representative of those used in pesticide formulations are listed in Table 6.5. 

Table 6.6 is provided as a final aid for protective glove selection decisions. Table 6.6 identifies the preferred glove types as well as those not recommended for use with pesticide formulations containing various carrier solvent types. The glove types identified as preferred are those that consistently provide the best permeation resistance to pesticide formulations and undiluted carrier solvents within each chemical classification identified. The glove types identified as not recommended are those that consistently provide very poor permeation resistance. Also note that the recommendations in Table 6.6 are... 

Every sprayer must have agitation to keep the spray material uniformly mixed. If there is too little agitation, the pesticide will be applied unevenly. If there is too much agitation, some pesticides may foam and interfere with pump and nozzle operation. The type of agitation necessary depends on the pesticide formulation to be used. 

With chronic or sustained exposure to pesticides, the populations at risk are those who receive repetitive exposures during the manufacture, formulation, mixing, application, or disposal of pesticides. Another type of chronic exposure is persistent residue contact by workers in the field during the harvesting and thinning of fruits, vegetables and other agricultural commodities. The outcome of these repetitive exposures can result in a number of different diseases. 

Table 4.1 Types of closed transfer system developed for handling liquid pesticide formulations... 

The main types of equipment considered here are the hydraulic sprayers, such as compression (Figure 5.1) and lever-operated knapsack sprayers (Figures 5.2, 5.3) normally used for residual applications to surfaces. Hydraulic sprays may also be applied with motorised pumps on knapsack sprayers, or larger units are carried on a trolley (Figure 5.4) or small vehicle. Pesticides formulated for dilution in water are frequently applied at volumes of around 100-500 litres per hectare. Other types of space treatments and more specialised equipment are considered later. 

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