Commercial pesticides

A critical study has been carried out in order to evaluate the capabilities of Near Infrared spectroscopy for the analysis of commercial pesticide formulations using transmittance measurements. In this sense, it has been evaluated the determination of active ingredients in agrochemical formulations after extraction with an appropriate solvent. 

If you frequently analyze pesticides, obtain the latest edition of Mass Spectrometry of Pesticides and Pollutants (Safe and Hutzinger. Boca Raton, FL, CRC Press). This book, combined with the list of most abundant ions (Table 25.1) and/or a computer library search, will be sufficient to identify most commercial pesticides. Also, see Chapters 17, 26, and 27. 

Although the extent of absorption was not measured, the above evidence suggests that absorption in humans occurs rapidly following dermal exposure to commercial pesticide formulations of methyl parathion. 

Jorgenson TA, Rushbrook CJ, Newell GW. 1976. In wVo mutagenesis investigations of ten commercial pesticides [Abstract]. Toxicol Appl Pharmacol 37 109. 

It Is now a relatively straightforward matter to analyze commercial pesticide mixtures for nitrosamlne contamination as part of the normal quality control process (2.18). and, as Illustrated above, some of the major contamination problems have begun to be solved by means of technological Improvements. If further research brings about the circumstance In which there Is no detectable N-nItroso compound In any pesticide sold an here, will that mean that pesticide use Is safe from nitrosamlne-formatlon problems I believe that considerably more research must be done before a responsible answer to this question can be given. To elaborate on this position, let me focus on the herbicides for a moment. 

The literature has numerous citations on both the prevention and destruction of nitrosamines. Techniques, such as the use of scavengers or selective reactions, may be applied to commercial pesticide products. 

A polyethylene-coated (PEE) silica column was used with water-methanol eluents to achieve the separation and retention of 27 pesticides.40 The retention times of 33 commercial pesticides were determined on an octadecyl (ODS)-derivatized alumina column using water-methanol eluents and compared with retention properties on an ODS-silica column packing.41 More recently, RP-HPLC was used in combination with diode array detection for the identification and quantification of 77 pesticides (acidic, basic, and neutral) in groundwater samples.42... 

The hydrobromide of ( )-6-chloro-5-(2-thienylvinyl)-2,3-dihydro-imidazo[2,l- ]thiazole 127 was found to be potent as an inhibitor of mitochondrial NADH dehydrogenase becoming a preferred target of commercial pesticides, especially insecticides and acaricides <1995JME1090, 1999EJM883>. 

A farmer, however, disposing of waste pesticides which are hazardous wastes, from his own use, is not required to comply with the RCRA notification or management standards provided he triple rinses each emptied pesticide container and disposes of the pesticide residues on his own farm in a manner consistent with the disposal instructions on the pesticide label. This exemption from the RCRA management controls does not apply, however, to commercial pesticide applicators. 

Over the past five years, a system for removing pesticides from the wash water produced by pesticide applicators as they clean their equipment has been developed. The system incorporates a two-stage treatment process. The first step is the flocculation/coagulation and sedimentation of the pesticide contaminated wash water. The supernatant from the first step is then passed through activated carbon columns. This paper describes the development of the system, the evaluation of the system s adequacy to handle a wide variety of pesticides, and the recommendations on the implementation of this system to commercial pesticide applicators. 

Commercial pesticide applicators are faced with a serious problem in the proper disposal of the large volumes of pesticide contaminated wastewater that are produced during the cleanup of application equipment. Various studies (Whittaker et al. 1982) have reported that the typical agricultural pesticide applicator will produce between 100 and 400 liters of pesticide-contaminated wash water each time he cleans the equipment. For a typical applicator, this amounts to approximately 20,000 liters of waste annually from each piece of equipment (i.e., airplane or truck) that he uses. 

The Resource Conservation and Recovery Act (RCRA) was enacted in 1976 and was revised substantially by the Hazardous and Solid Waste Amendment (HSWA) of 1984 (40 CFR pts. 260-280). The RCRA regulates the management of solid wastes that are hazardous. The definition of solid wastes in these regulations generally encompasses all discarded materials (including solid, liquid, semisolid, and contained gaseous materials) and many secondary materials (e.g., spent solvents, byproducts) that are recycled or reused rather than discarded [3]. Products such as commercial pesticides are not ordinarily solid wastes, but they become solid wastes if and when they are discarded or stored, treated, or transported prior to such disposal. 

Solanine hydrochloride has been used as a commercial pesticide. It has sedative and anticonvulsant properties, and has sometimes been used for the treatment of asthma, as well as for cough and common cold. However, gastrointestinal and neurological disorders result from solanine poisoning. Symptoms include nausea, diarrhoea, vomiting, stomach cramps, burning of the throat, headaches and dizziness. Other adverse reactions, in more severe cases, include hallucinations, loss of sensation, paralysis, fever, jaundice, dilated pupils and hypothermia. Solanine overdose can be fatal. 

Some of the closely related organic sulfides and thioacetals have found commercial pesticidal use. These formulations include Mikazin. Fluoroparacide. and Fluorosulfacide. Names are proprietary in most cases. 

Similiarly variable is the systemic activity of these compounds, that is the translocation in the vascular system of the plant. In this respect, cymoxanil with its very localized distribution, and fosetyl with its fast and strong translocation both acropetally and basipetally, are the extremes (Table IV). From this point of view, fosetyl is the most remarkable structure it is the only commercial pesticide showing effective acropetal and basipetal translocation at normal use rates. 

In the preparation of commercial pesticide formulations, the biochemical and toxic properties undergo phenomenal modifications. These reactions (and the effects thereof) are called synergism, antagonism, and additive effects. In pest control management, different OPs are mixed to achieve quick knock-down effects, and absence of residues effects, for the better killing of crop pests (Table 5-2). 

Miraculously, few human tragedies have definitely been traced to 2,4,5-T or TCDD, in war or peace. Further investigation indicates that environmental break-down may be largely the reason. TCDD is very unstable to sunlight when it is present as a trace contaminant in commercial pesticides (Fig. 10) (33,34), especially when applied to inert surfaces or leaves. The present lack of evidence for widespread occurrence of TCDD in the environment may be directly related to its environmental chemistry. The knowledge that the detoxication and loss occur through reductive dechlorination by the solvent also opens the way for intentional TCDD destruction or decontamination. 

These studies do not confirm the effect of formulations on the bioavailability of compounds, but they do emphasize the need to test formulations (next to or instead of active ingredients) when performing a risk assessment of commercial pesticides (Garcia-Ortega et al. 2006). 

A number of current commercial fungicides have been reported to enhance disease resistance in addition to direct fungitoxicity (103,105,107). Figure 3 presents structures of commercial pesticides reported to enhance endogenous plant disease resistance mechanisms. 

Figure 3. Commercial "pesticides" reported to enhance endogenous plant disease defense mechanisms.

The first of the organophosphorus insecticides to gain widespread use was parathion which is still an important commercial pesticide. This compound (Figure 9) is converted to the S-ethyl isomer by heating whereas paraoxon, a more toxic compound, is formed by enzymic action in plants. In animals, the additional products, p-nitrophenol and p-amino-phenol, are also formed. At present, little information appears to be available regarding the decomposition products of parathion in soils. 

Tphe search for insecticides with modes of action different from the A well-known acetylcholinesterase inhibition led us to uncouplers of oxidative phosphorylation (1, 2). An inherent advantage of such pesticides would be the absence of cross-resistance with organophosphorus compounds and chlorinated hydrocarbons. The number of commercial pesticides which are likely to act by uncoupling of oxidative phosphorylation is small. All of them can be regarded as derivatives of the... 

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. 

Several analytical methods for speciating arsenic have been reported. They include chromatographic techniques such as electrophoresis and ion-exchange (17), paper chromatography (18) and HPLC (19) selective volatilization of arsenic compounds to analogous arsines followed by GC-MES (20) boiling point separation/spectral emission (21) and atomic absorption (22). The above techniques have been applied to samples such as commercial pesticides (20),coal and fly ash (23),rocks, sediments, soils and minerals (24, 22),plant tissue (18), bovine liver (23),and water samples T25). 

The information in this book is focused toward those involved in handling, mixing, and applying pesticides. It should be especially useful to commercial pesticide applicators, formulators, and handlers as well as employees of city, county, state, and federal agencies. Pesticide dealers, salespeople, consultants, and trainers should also find it helpful in their work. 

U-List - Toxic and other commercial products (40 CFR 261.33[f]). Both the P-List and the U-List contain several commercial pesticides. 

Operators of agricultural establishments must make sure any commercial pesticide establishment operator they hire is aware of... 

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