Pesticide, liquid

The vaporous collar contains a relatively high-vapor-pressure liquid pesticide mixed throughout the collar. The pesticide is slowly released and fills the atmosphere adjacent to the animal s surface with a vapor of pesticide that kills the pest but is innocuous to the animal. 

Recently, the pesticide company experienced two accidents. The first accident was a small fire of a mixture of liquid pressurised gas and liquid pesticide, which resulted in some material damage. The second accident was an instantaneous release of pesticide powder, which resulted in a number of operators requiring treatment for respiratory problems in a local hospital. Management recognised that safety problems had to be addressed. Additionally, a major concern for the company was the high financial penalties which resulted from late deliveries. Both the safety and the reliability of the operational process had to be improved. The management thought that operator errors were the cause of almost all the problems in the process. 

The primary method for the disposal of liquid pesticide wastes in California in the past has involved soil evaporation pits, ditches, and ponds (Winterlin et al. 1989). A core soil sample taken from one such pit in northern California contained 44 mg/kg disulfoton at a depth of 90 cm (Winterlin et al. 1989). Disulfoton was detected in six of seven bottom soil samples from tail water pits used to collect irrigation runoff in Haskell County, Kansas, in 1974. The maximum and mean concentrations of disulfoton in these samples were 32.7 and 13.42 pg/kg respectively (Kadoum and Mock 1978). At a detection limit of 0.01 mg/kg, disulfoton was not detected in sediment samples collected from Lakes Superior and Huron, including Georgian Bay, in 1974 (Glooschenko et al. 1976). 

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). 

The use of closed systems has been required in California for transfer of toxicity category one liquid pesticides from the manufacturer s container into the mix tank and then into the application vehicle tank. It appears that this process has considerably reduced both dermal and inhalation exposure. The use of probes that are inserted and then removed from containers reduces dermal exposure up to ten-fold it also appears that the use of built-in probes further reduces exposure to the mixer-loader by up to another ten-fold factor in some cases. 

Physical parameters which control the dispersion, deposit, coverage (of target plants) as well as drift losses of liquid pesticides released from aircraft In mountainous forest land are (1) spray drop size and spray formulation, (2) local meteorology, (3) local terrain at spray site and (4) type of application aircraft. 

Dermal Exposure Of the three major routes of exposure, the dermal (skin) route constitutes nearly 90% of chemical exposure, particularly of pesticides. Dermal exposure is common whenever chemicals are mixed or handled. Certain types of dry materials, (e.g., pesticide dusts, wet or dry powders, granules, liquid pesticides) enter the body through quick skin absorption. Many factors influence the rate of dermal exposure of a chemical these may be as follows ... 

One problem in using these techniques is getting sufficient quantity of pesticide adhered to the seed or fertilizer granule. Solutions to this problem include using a powdered clay or silica to help absorb liquid pesticides, using microencapsulated liquid pesticides, and using a polymer coating to increase adhesion of pesticide particles. 

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]. 

Two distinct controlled release technologies are encapsulation of liquid pesticides and the coating of individual pesticide crystals. Encapsulation of liquid pesticides is an established tool for modem formulators. Commercial microencapsulated pesticide products exist and new developments continue to be made. Coating of individual pesticide crystals without their aggregation is more difficult. While new processes do exist to coat pesticide crystals without aggregation these processes have not yet been utilized to create commercial pesticide products. 

Processes are now available to provide controlled release to liquid pesticides, molten lower melting point pesticides, and solid higher melting point pesticide crystals in the size range and volume demanded of pesticide products. These processes will continue to develop into more robust and simpler systems. New processes wiU be developed. 

Liquid pesticide spills can be further contained by covering the entire spill with absorbent materials, such as spill pads, blankets or pillows, absorbent clay, vermiculite, sawdust, com cobs, expanded silica, or other acceptable material. 

For spilled liquid pesticides, sweep up the absorbent material containing the pesticide and place it into a heavy-duty plastic drum or bag. Keep adding the absorbent material until the spilled liquid is soaked up and removed. Do not use more absorbent than is necessary to clean up the spill. It also must be disposed of properly. 

The pump must have sufficient pumping capacity to supply the needed volume to the nozzles and to the hydraulic agitator (if necessary) and to maintain the desired pressure. The pump parts should be resistant to corrosion and abrasion if abrasive materials such as wettable powders are to be used. Select gaskets, plunger caps, and impellers that are resistant to the swelling and chemical breakdown caused by many liquid pesticides. Consult your dealer for available options. 

Nozzle tips break the liquid pesticide into droplets. They also distribute the spray in a predetermined pattern and are the principal element that controls the rate of application. Nozzle performance depends on ... 

The Mist-O-Matic treater applies the pesticide as a mist directly onto the seed. The treater delivers one treatment cup of pesticide per dump of seed. The pesticide flows onto a rapidly whirling disc which breaks the liquid pesticide into a fine mist. The seeds fall onto a large cone which spreads the seeds out so they are evenly coated with the pesticide spray mist. The desired dosage is obtained by selecting the appropriate treatment cup size and adjusting the seed dump weight. 

Dipping vats are large tanks (vats) of liquid pesticide mixture used to treat livestock for external parasites. They are used in farm, ranch, and regulatory pest control operations. Portable dipping vats are usually trailer-mounted tanks with a set of folding ramps and railings. The animals are driven up the ramp onto a platform and forced into the tank so they are completely immersed. The animal s head may have to be pushed under the surface. 

Inert ingredients in liquid pesticides include water, alcohol, and other solvents. Pesticide powders and dusts often contain added diatomaceous earth, powdered seeds, or talc for added bulk, or fuller s earth to help prevent caking. Other inert ingredients, known as surfactants, help powders mix easily with water or help sprays adhere to foliage so that pests are more likely to contact it. In the absence of surfactants, many pesticide sprays would simply roll off waxy leaf surfaces. Soap is one of the most common surfactants added to pesticide sprays. 

The first type is evaluated as a start of contamination, and the second type as already to be contaminated. It is important to reveal the tendency of water impairment at initial stages to prevent the further contamination of ground water. Percolation or seepage of indnstrial and domestic liquids, pesticides, as well as natural substandard waters into operating aquifers may result in gronnd water contamination. Abandoned wells might also result in ground water contamination. 

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

Liquid pesticide in both bulk and non-bulk quantities... 

Since 1962, agrochemicals and chemical fertilisers have been distributed in Nepal by the Agriculture Inputs Corporation (AIC), a public enterprise owned by the government. Private sector traders also play a major role in pesticide distribution, reselling agrochemicals purchased from AIC. In 1994, AIC distributed about 335 metric tonnes of dust and granulated pesticides and about 2460 litres of liquid pesticides. ... 

---