Insecticides in water

Thus, at present, the input of unused DDT and HCH insecticides in water and bottom sediments of the rivers and reservoirs of the Caspian Sea basin is mainly connected with loss or leaching from old RPA or young LPA. As regards PCBs, their input is mainly related to industrial sources. The high toxicity of POCs for organisms and their persistence in the water and sediments are the principal forms of ecological risk for rivers and the Caspian Sea. The behavior of POCs in the northern part of... 

Sharom MS, Miles JR, Harris CR, et al. 1980b. Persistence of 12 insecticides in water. Water Res 14 1089-1093. 

Biggar, J.W. and Riggs, I.R. Apparent solubility of organochlorine insecticides in water at various temperatures, Hilgardia, 42(10) 383-391, 1974. 

Hoffman, J. and Eichelsdoerfer, D. Effect of ozone on chlorinated-hydrocarbon-group insecticides in water, Vom. Wasser, 38 197-206, 1971. 

Sun, Y. and J.J. Pignatello (1993). Activation of hydrogen peroxide by iron(III) chelates for abiotic degradation of herbicides and insecticides in water. J. Agile. Food Chem., 41 308-312. 

The American Public Health Association [97,98] published an early gas chromatographic method for the solvent extraction and gas chromatographic determination of 11 chlorinated insecticides in water samples in amounts, down to 0.005mg L 1 p,p -DT)E, p,p -DDT, Aldrin, Dieldrin, Endrin, Heptachlor, Heptachlor epoxide, Lindane, Isodrin and Methoxychlor. The insecticides Carbophenothion, Chlordane, Dioxathion, Diazinon, Ethion, Malathion, Parathion methyl, methyl Trithion, Parathion, Toxaphene and VC-13 may be determined when present at higher levels. Also, the chemicals chlordane, hexachlorobicycloheptadiene and hexachlorocyclopentadiene, which are pesticide manufacturing precursors, may be analysed by this method. 

If the other product from the hydrolysis is phenol, the procedures described in Section 5.1 are applied to the preparation of the derivatives, particularly those which permit a very sensitive analysis. Perfluorinated acyl derivatives and 2,4-dinitrophenyl-, 2,6-dinitro-4-trifluoromethylphenyl and pentafluorophenyl ethers are frequently used [482], when concentrations of 0.01—0.1 ppb of the insecticide in water can be determined. 

Another common misconception about the fate of chlorinated hydrocarbon insecticides in water is that they remain there forever. Like the soil, aquatic environments are dynamic systems. Residues of chlorinated hydrocarbons dissipate from aquatic environments by codistillation phenomena, metabolism, decomposition, and absorption on surfaces where they are subject to like dissipation forces. Table IV shows the loss of various insecticides by codistillation 20 hours after they were introduced into a jar of water containing mosquito larvae (2). This work was based on still systems. Recent work by investigators at Washington University... 

Determination of Organic Insecticides in Water by Electron Capture Gas Chromatography... 

Picer, N., Picer, M and Perkov, S., Polychlorinated Biphenyls and Chlorinated Insecticides in Water and Fish of the Kupa River , in Proceedings of the Conference on Water Protection ZaStita voda 86 , Kragujevac 1986, pp. 291-296 (in Croatian). 

Caibamate insecticides in water are subject to photo decomposition under the effects of ultraviolet radiation, the rate of which is related with pH, tending to increase with increasing pH. The first effect of UV irradiation is the cleavage of the ester bond, resulting in the phenol or the heterocyclic enol of the carbamate ester [9]. The studies concerning the half-life for photo decomposition process suggest that the light source characteristics influence the extent of the process. 

McGinnis, S. C. and Sherma, J., Determination of carbamate insecticides in water by Cig solid-phase extraction and quantitative HPTLC, J. Liq. Chromatogr., 17, 151-156, 1994. 

Croll, B. T., Levels of Organic Chlorine Insecticide in Water, Part I, Soc. 

The decomposition of a certain insecticide in water at 12 °C follows first-order kinetics with a rate constant of 1.45 yr . A quantity of this insecticide is washed into a lake on June 1, leading to a concentration of 5.0 X 10 g/cm. Assume that the average temperature of the... 

The present work consists of a comparative study of three different extraction techniques—specifically, liquid-liquid extraction (LLE), solid-phase extraction (SPE), and supercritical fluid extraction (SEE)—for the trace analysis of fipronil insecticide in water samples. The extracted fipronil was analyzed via high-resolution gas chromatography using electron capture detection (HRGC-ECD). The extraction methods presented linear calibration all over the investigated concentration range (0.1-1.0 pg/L). The limit of detection (LOD) was determined at 0.1 pg/L concentration level, and precision, measured by the relative standard deviations (RSD), was 7.7% for LLE, 7.8% for SPE, and 0.5% for SEE. 

Sherma, J. Bretschneider, W. Determination of organopho-sphoms insecticides in water by C-18 solid phase extraction... 

These herbicide analyses were later simplified by replacing the liquid-liquid extraction by a solid phase extraction (SPE) on a C-18 bonded silica gel disposable column (76). Another application of C-18 SPE was in the determination of carbamate insecticides in water by quantitative HPTLC (77). Solid phase extraction is discussed in detail below. 

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