Pesticide undesirable effects

Potentiation The increase in toxicity (usually considered an undesirable effect) of a pesticide when combined with one or more pesticides. 

Many organochlorine pesticides (OCPs), which have shown undesirable effects in humans and the environment, have been banned in developed countries. Even so, OCPs deserve particular attention, for they are very stable and can accumulate in food chains (9). Products of animal origin as well as human mother s milk almost always contain residues of organochlorine compounds. The residue content of this milk is 10-30 times higher than that of cow s milk (10,11). 

Depending on the toxicity, formulation concentration, and use patterns, pesticides can be classified as general or restricted use. A general use pesticide will cause no unreasonable, adverse effects when used according to the label and can be purchased and applied by anyone. A restricted use pesticide, defined as generally causing undesirable effects on the environment, applicator, or workers can only be purchased and applied by an individual who is licensed by the state. 

Pesticides are useful tools. But wrong or careless use could cause undesirable effects. To help avoid this the label provides precautions for protecting nontarget organisms and the environment. Some general statements appear on the label of almost all pesticides for example, most labels warn not to contaminate water when you apply or dispose of pesticides. The label will contain specific precautionary statements if the pesticide poses a specific hazard to the environment. Some examples are ... 

Another advantage of pestiddes-CyD complexes is the masking of undesirable effects of the guest molecule. The irritating or toxic effects of some pesticides can be reduced or eliminated. When a guest is included in a molecule of CyD, it is isolated and prevented from coming into contact with body surfaces where it could cause unwanted side effects such as irritation. Loukas et al. [47] prepared y-CyD complexes of the insecticide DCPE and observed a decrease of its acute oral toxicity, indicating that a safer product for the applicator had been prepared. 

Pneumonitis (Chemical) Inflammation of the lungs resulting from inlialation of chemical vapors and characterized by an outpouring of fluid in the lungs. Potentiation The increase in toxicity (usually considered an undesirable effect) of a pesticide when combined with one or more pesticides. 

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 undesirable effects of chlorinated pesticides and PCB are closely associated with their tendency to accumulate in the fatty tissues of animals, where they are found at concentrations rising to hundred of parts per million. By contrast, the concentrations reported for the C1-C2 chlorocarbons are of the order of a few parts per billion which is three to five orders of magnitude lower [43]. The significant compounds (Table 7) are chloroform and carbon tetrachloride, trichloroethylene, perchloroethylene and methyl chloroform. Methyl chloride, methylene chloride and ethylene dichloride were not detected but the analytical method used did not resolve lower MW compounds while traces of hexachloro-butadiene were found in some marine organisms from an area known to receive industrial effluents. The compounds found in the animals were also found in a few samples of marine algae but at the time of sampling, the analytical method for methyl chloride was not adequate to show its presence. 

Examples of Synthesis Routes Inherently Safer Than Others As summarized by Bodor (1995), the ethyl ester of DDT is highly effective as a pesticide and is not as toxic. The ester is hydrolytically sensitive and metabolizes to nontoxic products. The deliberate introduction of a structure into the molecule which facilitates hydrolytic deactivation of the molecule to a safer form can be a key to creating a chemical product with the desired pesticide effects but without the undesired environmental effects. This technique is being used extensively in the pharmaceutical industry. It is applicable to other chemical industries as well. 

Another major trend in performance chemicals is towards the development of products, e.g. drugs, pesticides, food additives, etc., that are more targeted in their action, with less undesirable side-effects. 

Several widely used pesticides are highly chlorinated polycyclic compounds derived from hexachloropentadiene. They include Aldrin, Dieldrin, and Chlordane. Use of these substances is to be curtailed greatly because of undesirable environmental effects. 

Another major trend in performance chemicals is towards the development of products - pharmaceuticals, pesticides and food additives, etc. - that are more targeted in their action with less undesirable side-effects. This is also an issue which is addressed by green chemistry. In the case of chiral molecules that exhibit biological activity the desired effect almost always resides in only one of the enantiomers. The other enantiomer constitutes isomeric ballast that does not contribute to the desired activity and may even exhibit undesirable side-effects. Consequently, in the last two decades there has been a marked trend towards the marketing of chiral pharmaceuticals and pesticides as enantiomeri-cally pure compounds. This generated a demand for economical methods for the synthesis of pure enantiomers [127]. 

Degradation is any undesirable change in a physical property or the appearance of the PPE material. Examples include swelling, shrinkage, loss of puncture and tear resistance, and an increase in stiffness due to exposure to pesticides. The degradation effects of a pesticide on PPE materials can be assessed in the laboratory or in the field. 

Many factors affect the ability to place a pesticide on the target in the manner and amount for most effective results, with the least undesirable side effects, and at the lowest possible cost. Certainly the selection and use of equipment are of utmost importance and deserve major emphasis when considering pesticide application. However, without proper consideration to calibration, formulation, adjuvants, compatibility, and use records, successful appli-... 

The tremendous achievements which have been accomplished by the judicious use of pesticides in increased world-wide food production and the control of vector-bome diseases are very evident. In addition, pesticidal materials contribute to the effective control of undesirable species of pests including insects, plants, bacteria, fungi, etc., and assist in the nutrition, growth, and reproduction of certain desirable species. However, because of widespread use in these applications, pesticides have proliferated intensely in the biosphere and thus have significantly contributed to problems of environmental pollution. For example, the effects of these chemicals on public health and the survival of species of fish and wildlife are two specific areas of critical concern. The attention which has been focused in recent years on the occiurence of residues of pesticides and their metabohtes, as well as other industrially significant chemicals in the environment, is demonstrated by the numerous reports of various official and unofficial committees of inquiry which have considered this problem and have reported the results of large numbers of assays of pesticide residues in such diverse substrates as human and animal tissues, food, plants, water, soil, and air. 

The early success in malaria control can be attributed to the use of professional spray teams who treated the inside of huts with DDT, without any direct involvement of the infected population. However, the problem with pesticides like DDT is that they lack specificity, and as application is not always well directed there is often destruction of a wide range of insects, which may have undesirable side-effects. Further problems include the accumu-... 

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