Examples of pesticides

Thus, this is a global phenomenon of fundamental importance for life on Earth many pesticides and/or their transformation products may substitute their activity for the hormonal system. Many earlier known examples of pesticide activity take on a dire new side in light of these views. Let us provide some illustrations ... 

Fig. 12.11 Examples of pesticide concentration vs. depth, indicating preferential flow of each pesticide in individual field plots. Symbols C continuous I intermittent P ponding S spiinkhng TG technical grade EC emulsifiable concentrate WP wettable powder U undisturbed D disturbed (Ghodrati and Jury 1990)...

Figure 2.24 Some additional examples of pesticides exhibiting a somewhat more complex structure.

In the case of pesticides which are not ChE inhibitors, exposure is measured by the analysis of blood and/or urine for the active ingredient or its metabolites. Baseline levels of pesticides and/or metabolites are not usually determined, with the exception of methyl bromide. In this case, a blood sample is taken to check for bromide ion before fumigators use the pesticide. Blood and urine tests are run only in the case of spills or other accidents to assist in identifying the cause of poisoning or to monitor workers in a workplace. Paraquat, chlorinated hydrocarbons, mercury, p-nitrophenol, and dinitrophenol are examples of pesticides or metabolites of pesticides that have been found in the urine of exposed workers. 

The following are examples of pesticide wastes which can be regulated under RCRA ... 

Several examples of pesticide nomenclature are given below ... 

FIGURE 1. Examples of pesticides derived from phenols... 

Many products used by the agricultural industry are based on chemicals derived from hydrocarbons. DDT and chlordane are examples of pesticides produced from hydrocarbon chemicals in the past. During the height of their use, they made enormous increases in the yield of crops by reducing insect damage. Their use was discontinued because of their damage to other parts of the environment. 

Delayed neurotoxicity results from degeneration of the axons followed by demyelination (14,15,23). Clinical manifestation includes sensory disturbances, ataxia, weakness, muscle twitching and, in severe cases, complete flaccid paralysis ( 15). A fair number of organophosphate compounds are capable of inducing delayed neurotoxicity. Of the 250 organophosphates (not all pesticides) tested for delayed neurotoxicity in chickens, 47% (117 chemicals) showed positive responses (23). Notable examples of pesticides which possess this neurotoxicity are leptophos, EPN, merphos, dichlorvos, and... 

The fungicides in this group are good examples of pesticides that react with sulfydryl groups in many enzymes ... 

Table I. Examples of Pesticides Reported to Modulate Immunity...

Low resolution mass spectrometry (MS), especially in tandem with gas chromatography, and nuclear magnetic resonance (NMR) spectroscopy have been reviewed with respect to their application to pesticide residue analysis. Sample preparation, direct probe MS analysis, GC-MS interface problems, spectrometer sensitivity, and some recent advances in MS have been studied. MS analyses of pesticide residues in environmental samples (malathion, dieldrin, dia-zinon, phenyl mercuric chloride, DBF, and polychlorinated biphenyls) have been illustrated. Fragmentation patterns, molecular ions, isotope peaks, and spectral matching were important in the identification of these pesticides. The sensitivity limitations of NMR and recent improvements in sensitivity are discussed along with examples of pesticide analyses by NMR and the application of NMR shift reagents to pesticide structure determinations. 

Some anecdotal accounts are included in the following examples of pesticide poisonings in order to supplement the comparatively scarce number of studies and official records and to cover as many countries as possible for some countries, anecdotal accounts were the only source of information that could be found. 

It has been shown that improved performance is obtained if the applied voltage is pulsed rather than applied continuously. A square-wave pulse of around -50 V is applied at a frequency that maintains a constant current whether or not an analyte is in the cell consequently the pulse frequency is higher when an analyte is present. The pulsed ECD has a lower MDQ and consequently a larger linear range. An example of pesticide residue analysis at the femtogram level is shown in Figure 7.14. 

This review will focus on similarities and differences of pesticide metabolism by plants and prokaryotic organisms. Examples of pesticide biotransformations will be used to illustrate how these metabolic processes can affect efficacy, environmental fate, and persistence. 

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