Pesticides, formulation examples

MIBK is a highly effective separating agent for metals from solutions of their salts and is used in the mining industries to extract plutonium from uranium, niobium from tantalum, and zirconium from hafnium (112,113). MIBK is also used in the production of specialty surfactants for inks (qv), paints, and pesticide formulations, examples of which are 2,4,7,9-tetramethyl-5-decyn-4,7-diol and its ethoxylated adduct. Other appHcations include as a solvent for adhesives and wax/oil separation (114), in leather (qv) finishing, textile coating, and as a denaturant for ethanol formulations. 

Incineration of pesticides and/or containers requires special equipment that Is not widely available. Due to the highly specialized nature of an Incinerator that can meet the specifications necessary to destroy complex pesticide formulations, plus the energy requirements, the process can be very expensive and not generally the method of choice for small quantities that may be generated by a fanner, for example. On the other hand. It can be a highly effective means of disposing of unwanted material (14). 

In order to minimize waste as well as to direct selectivity, a number of approaches toward dissipation-control are being examined. For example, both volatilization and photodecomposition often can be regulated to a desired degree by incorporation of a non-volatile resin additive into the pesticide formulation (35). The technique appears promising for insecticides, and there is no reason to believe it should not work for herbicides also. Another approach is inhibition of microbial break-down for example, N-methylcarbamate inhibitors of hydrolytic enzymes, such as PCMC ( -chlorophenyl N-methylcarbamate), applied together with a herbicide such as chloropropham [isopropyl N-(3-chlorophenyl)carbamate] which is inactivated by soil microbes, more than doubled the effectiveness (36,37). 

The objective of this report is to discuss with the help of an illustrative example, the applicability of computer-assisted methods to the development of pesticide formulations. The example describes the process of planning and conducting a study to obtain an empirical equation which correlates the suspensibility of a wettable powder with its composition. 

The handling properties of the formulation in the field. Examples of handling properties are the amount of dust in the product (in the case of dry formulations), the manner in which the product dilutes with water (or other carrier liquid), the way in which the product sprays through an agricultural spraying system, and the manner in which the product will tank mix with other pesticide formulations. This paper is addressed to this last concern. 

Ionic surfactants may cause complications with water during application. For example, in hard water, there is an excess of Ca++, Mg++, Fe++, S04, and other inorganic ions. These will react with the anionic or cationic ions of the surfactant to form insoluble salts that precipitate, removing the surfactant from the spray solution. This will result in reducing the surface active properties of the surfactant. For this reason, pesticide formulators often use both ionic and nonionic surfactants in their formulations. Because the latter agents do not ionize, they are not as likely to react with the constituents of hard water. 

Analytical surveys need to be carried out in developing countries in order to provide detailed information about the dimensions of the stockpiles. As a general rule, the storehouses are mostly inappropriate. It is also difficult to estimate the exact quantities of the individual stockpiles. In Pakistan, for example, several hundred different pesticide formulations with 50 different active ingredients were found in the stores, mostly insecti-... 

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. 

In addition to their active compounds, pesticide formulations often contain by-products of the manufacturing process and a quantity of inert ingredients. The potential contribution made by all known or potential additional components in any pesticide preparation must be considered in assessment of a pesticide for immunotoxic potential. For example, 0,0,S-trimethyl phosphorothioate (OOS-TMP), a contaminant of malathion, has been shown to alter immune function (19,... 

Some investigators have also studied the interaction of the pesticide with the other compounds found in pesticide formulations. For example, in a study comparing the... 

Declaration of toxicological, ecotoxicological, or environmental significant impurities is needed. Especially hazardous chemicals like, for example, nitrosamines have to be declared and are regulated by a maximum admissible concentration. In this example, the total nitrosamine content of a pesticide formulation must not exceed 1 mg kg of the active substance present. 

Numerous studies demonstrate that inert ingredients enhance the toxicides of the active ingredients in pesticide formulations [27]. Examples of such effects are as follows. 

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. 

---