Pesticides liquid formulations

A water soluble liquid formulation (WSL) is prepared from pesticides that are highly water soluble. This is, by far, the simplest type of formulation. One distinct advantage of WSL s over other formulations is that the field spray dilutions are infinitely stable as true solutions. Pesticides that are hydrophilic and ionic, such as inorganic or organic metallic salts, often fall into this category. Unfortunately, only a small portion of all pesticides are adequately soluble in water. 

The pH measurements of the mixed contents were made immediately after taking the soil and liquid samples. The presence of a very large amount of suspended sediment affected the accuracy and reproducibility of these pH measurements. The average values for each container are summarized in Table II. The deposited pesticides, the formulating agents and the decomposition products did not change the pH from that observed for ambient water except for... 

A typical liquid formulation unit is depicted in Fig. 5 [8]. Until it is needed, technical grade pesticide is usually stored in its original shipping container in the warehouse section of the plant. When this material is received in bulk, however, it is transferred to holding tanks for storage. 

Figure 5 Liquid formulation unit. Technical grade pesticide products are blended with solvents and emulsifiers or other agents in a mix tank. Formulated products are filtered before packaging (from Ref. 8).

The Committee recommended that over-the-counter supply of pesticides for mosquito net treatment should include presentation in single-unit doses only, and that liquid formulations should be packaged in containers with child-proof caps. 

Pesticides and fertilizers are usually applied at the soil surface either in granular or liquid formulations and are subsequently incorporated by some sort of tillage operation (e.g., discing). 

Number and Location of Observation Wells. The precise amount of pesticide which was applied to the soil surface and is available for leaching is known as the source term. For pesticides which are applied directly to the soil, such as granules or liquid formulations sprayed only onto the soil surface, the source term can be assumed to be equal to the total amount of application. 

Bromacil is very slightly soluble in water, so that much rain is needed for its activation. Its water-soluble formulation (Hyvar X-L) contains 21.9% bromacil lithium salt. It is incompatible with ammonium sulfamate, with the liquid formulations of aminotriazole, and with pesticides containing water soluble potassium salts. 

Emulsion concentrates (ECs) are one of the oldest formulation types for agricultural pesticides. Even today, ECs are a prevalent delivery system. As liquid formulations, with physical properties similar to the aqueous solution concentrates, these formulations are easy to use, transport, and mix. 

The World Health Organization (WHO) classification (shown in Table 5) also makes a distinction between toxicity and hazard and recognizes that liquid formulations are more hazardous. This international classification is based on a comparative analysis of the standards adopted by different countries for classifying pesticide toxicity. One new aspect in the WHO classification is the evaluation of pesticide products by concentration of active ingredient and formulation (solid or liquid). Other special considerations are products that cause irreversible effects, those for which the hazard of inhalation exceeds that of oral or skin entry, and those for which human health risks are greater than the risk to animals. 

Pesticides have been applied in a variety of formulations onto soils and crops for the control of insects, noxious weeds, fungi, and other bioagents that interfere in the production of food and fiber. Examples of such formulations are dusts, suspensions prepared from solid powders, and suspensions prepared from concentrated liquid formulations. The formulations, however, can have some undesired effects in that the active ingredient in these preparations can easily move about to a non-target area. Dusts can easily be carried for long distances away from the field even in the slightest winds. Evaporation to the atmosphere can take place with both dusts and liquid suspensions sprayed onto fields. 

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. 

Schreuder, R. H., Martijn, A., Poppe, H., and Kraak, J. C., Determination of the composition of ethoxylated alkylamines in pesticide formulations by high-performance liquid chromatography using ion pair extraction detection, /. Chromatogr., 368, 339, 1986. 

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]. 

Agricultural (Ag) formulations that are commonly diluted and applied by means of spray equipment include water soluble liquids, emulsifiable concentrates, wettable powders, and flowable suspensions. The choice of which formulation to develop normally depends upon the solubility properties of the technical pesticide. Scientists often must also consider manufacturing costs, field efficacy and product toxicity. 

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). 

Soil and Liquid Analyses. The behavior of the individual pesticides is best shown by the plots in Figures 3 and 4. Common names for the pesticides are alphabetized on the plots for convenience of location. The formulations deposited are shown immediately below the common names. The vertical axes are either 0-15, 0-150 or 0-1500 yg/g depending on the maximum concentration observed for any one residue. In some cases, such as benomyl and trifluralin in Figure 3, no data points are shown in 1977 because these pesticides were either not measured, as is the case for trifluralin, or the analytical schemes had not yet been devised as is the case for benomyl. Also no data points are shown for bensulide in 1977 because none had been dumped into the pit. 

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. 

TRW Systems, Inc., conducted a laboratory-scale incineration study for the U.S. Army from 1973 to 1975 (9). Eleven individual pesticide formulations and three mixed pesticide formulations containing six different active ingredients (chlordane, 2,4-D, DDT, dieldrin, lindane, and 2,4,5-T) were incinerated in a liquid injection incinerator. The experimental apparatus consisted of a fuel atomizer, combustion chamber, afterburner, quench chamber, and scrubber unit. Destruction efficiencies exceeded 99.99% for a minimum 0.4-s residence time at temperatures above 1000°C with 45 to 60% excess air. 

After a pesticide is manufactured in its relatively pure form (the technical grade material) the next step is formulation - processing a pesticide compound into liquids, granules, dusts, and powders to improve its properties of storage, handling, application, effectiveness, or safety [9]. The technical grade material may be formulated by its manufacturer or sold to a formulator/ packager. 

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