Insecticides accumulation

Table II - Ratios of Insecticide Accumulated in Livers to That in Brains in Susceptible (S) and Resistant (R) Fish Exposed to the l c-label led Insecticide for 6 hr...

Table IV - Ratios (Susceptible/Resistant S/R) of Insecticide Accumulated in Brains and Livers Following 6 hr of Relabelled Insecticide Exposure ...

DDT Insecticides Accumulates in food chain till eventually kills top predators... 

It is well known that the chlorinated hydrocarbon insecticides accumulate in the fatty tissues of the animal body and that their propensity for storage varies from compound to compound. There is ample evidence to show that most, and probably all, of the chlorinated hydrocarbon insecticides, when fed regularly at any given concentration in the diet, will reach an equilibrium in the fat. In fact, there is increasing evidence that the animal body will adapt to the toxicant and gradually metabolize the chemical at a faster rate. Figure 5 illustrates this point. Dieldrin fed to rats at a given level in their diets will show a rapid rate of accumulation in the fat for a few weeks and then will decline almost as rapidly until it reaches equilibrium (22). 

Lead ll) oxide, PbO, exists in two forms as orange-red litharge and yellow massicot. Made by oxidation of Pb followed by rapid cooling (to avoid formation of Pb304). Used in accumulators and also in ceramics, pigments and insecticides. A normal hydroxide is not known but hydrolysis of lead(II) oxyacid salts gives polymeric cationic species, e.g. [Pb OfOH) ] and plumbates are formed with excess base. 

Dieldrin [60-57-1] or l,2,3,4,10,10-hexachloro-l,4,4t ,5,8,8t -hexahydro-6,7-epoxy-l,4- <7o, Aro-5,8-dimethanonaphthalene (34) (mp 176°C, vp 0.4 mPa at 20°C) is formed from aldrin by epoxidation with peracetic or perben2oic acids. It is soluble in water to 27 / g/L. Aldrin and dieldrin have had extensive use as soil insecticides and for seed treatments. Dieldrin, which is very persistent, has had wide use to control migratory locusts, as a residual spray to control the Anopheles vectors of malaria, and to control tsetse flies. Because of environmental persistence and propensity for bio accumulation, registrations in the United States were canceled in 1974. 

Gasoline accumulator Solvents Storage vessels Lube oil refining Polyethylene gas vents Styrene Copper naphthenates Insecticides Phthalic anhydride Resin reactors Ammonia Chlorine solutions Dry cleaning Degreasers Tar dipping Kraft paper... 

Hurst (19) discusses the similarity in action of the pyrethrins and of DDT as indicated by a dispersant action on the lipids of insect cuticle and internal tissue. He has developed an elaborate theory of contact insecticidal action but provides no experimental data. Hurst believes that the susceptibility to insecticides depends partially on the cuticular permeability, but more fundamentally on the effects on internal tissue receptors which control oxidative metabolism or oxidative enzyme systems. The access of pyrethrins to insects, for example, is facilitated by adsorption and storage in the lipophilic layers of the epicuticle. The epicuticle is to be regarded as a lipoprotein mosaic consisting of alternating patches of lipid and protein receptors which are sites of oxidase activity. Such a condition exists in both the hydrophilic type of cuticle found in larvae of Calliphora and Phormia and in the waxy cuticle of Tenebrio larvae. Hurst explains pyrethrinization as a preliminary narcosis or knockdown phase in which oxidase action is blocked by adsorption of the insecticide on the lipoprotein tissue components, followed by death when further dispersant action of the insecticide results in an irreversible increase in the phenoloxidase activity as a result of the displacement of protective lipids. This increase in phenoloxidase activity is accompanied by the accumulation of toxic quinoid metabolites in the blood and tissues—for example, O-quinones which would block substrate access to normal enzyme systems. The varying degrees of susceptibility shown by different insect species to an insecticide may be explainable not only in terms of differences in cuticle make-up but also as internal factors associated with the stability of oxidase systems. 

The increase in Ca is initiated rapidly and begins to recover after 1 min. The order of potency correlates fairly well with the solubilities of these compounds in organic solvents (37) and their abilities to accumulate in phospholipid vesicles (38), i.e., 6>y>a>p, but not with their insecticidal activity (y 6>a p 39). At these concentrations, crystals of p-, a-, and y-HCH were evident in the cell suspensions when we made simultaneous measurements of the right-angle light scatter, indicating that the order of aqueous solubilities is 6>y>a>p. However, stimulation by 6-HCH at concentrations below its aqueous solubility limit shows a typical dose dependency of the response (Figure 10). 

Pesticides, including insecticides, herbicides, and fungicides, are widely used in agriculture, and the potential for these residues to accumulate in food has led to concern for human safety. Pesticide residues may enter food animals from environmental sources or from treated or contaminated feeds. Immunoassay development for pesticides has had major impacts for pesticide registrations, analysis of residues in foods, monitoring environmental contamination, determination of occupational exposure, and integration of pest management. 

As the value of these two new chemicals for insecticides became more evident, the need for extended experimental and test work was definitely established. It was necessary to determine chemical formulas, work out analytical methods, obtain knowledge of various physical and chemical characteristics, and complete evaluation of insecticidal action as well as toxicity and effect of residues. Toxicity was concerned with not only insects but humans and other warm-blooded animals. Residual studies included information on persistence and type and amount of residue. This information, once accumulated, must be correlated with similar information on other insecticides. 

When DDT is fed to animals, even in small quantities, there is an accumulation of the compound in the tissues, particularly the fat. Telford and Guthrie (18), Orr and Mott (13), Woodward et al. (20, 21), and Laug and Fitzhugh (9) have demonstrated that DDT will accumulate in certain tissues and in milk fat of domestic and laboratory animals. Marsden and Bird (12) found that DDT was toxic to turkeys in concentrations above 0.075% of the diet, and that turkeys fed the insecticide for 7 to 8 weeks stored DDT in their fat at concentrations ranging from 4 to 8 times that in the diet. Rubin et al. (14) reported that hens fed 0.062% DDT in their diet for 12 weeks showed reduced egg production with lowered hatchability. At one half this concentration there was a detrimental effect on egg production, but hatchability was not seriously affected. The hens were killed by doses of 0.125% DDT. The insecticide was found in the eggs in quantities much smaller than in the body fat. Harris et al. (8) have shown that DDT will accumulate in considerable quantities in the fat of lambs fed DDT-treated hay. Small amounts of the insecticide were found in other tissues. 

DDT met all but one of Muller s ideal characteristics for an insecticide. It was a cheap, contact poison without objectionable odors. It was stable in air and light. Because it was so powerful, extremely small doses could be used. And finally, it dissolved so poorly in water that warm-blooded organisms absorbed only traces of it. The fact that DDT dissolves well in oils did not seem dangerous only later did scientists realize that, because DDT accumulates in animal fat and mammals milk, it becomes increasingly more concentrated in predator species as it moves up the food chain. DDT s only failing, as far as Muller s original conception was concerned, was that it did not kill immediately. 

Carbamates are used as insecticides, nematocides, fungicides, and herbicides the toxicity of carbamate insecticides is similar to that of OP compounds and is based on the inhibition of ACHE. Also, carbamate metabolites may inhibit ACHE but are usually weaker inhibitors than the unchanged compound. Cholinesterase inhibition caused by carbamates is labile, of short duration, and rapidly reversible in fact, the half-life of the inhibited enzymes ranges between some minutes and 2 to 3 hours for RBC-ACHE and is on the order of some minutes for PCHE. Accumulation of cholinesterase activity on repeated exposures, as observed with OP compounds, does not occur with... 

The model was forced with agricultural application data of the insecticide DDT compiled by Semeena and Lammel (2003). Statistical data of DDT consumption reported by member of the UN states to Food and Agriculture Organisation (FAO) were combined with other published data (details in Semeena and Lammel (2003)). The emission inventory assumed 100 % of p,p -DDT. After scaling the DDT consumption with crop land distribution, the data were extrapolated to the model grid. The result was a data set with spatially and temporally varying applications (accumulated application and temporal evolution shown in Figure 3.1). No seasonal or diurnal variation of the applications is considered. 

Thirugnanam, M. and A.J. Forgash. 1977. Environmental impact of mosquito pesticides toxicity and anticholinesterase activity of chlorpyrifos to fish in a salt marsh habitat. Arch. Environ Contam, Toxicol. 5 415-425. Tsuda, T., S. Aoki, T. Inoue, and M. Kojima. 1994. Accumulation and excretion of pesticides used as insecticides or fungicides in agricultural products by the willow shiner Gnathopogon caerulescens. Comp. Biochem. Physiol. 107C 469-473. 

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