Organochlorines dissolved

Due to organochlorines dissolving in fats and oil, bioaccumulation in the food chain may occur. Figure 4 shows the simulation of the accumulation of a substance in fatty tissues under a regular intake. 

Ding, J.Y. and Wu, S.C. Partition coefficients of organochlorine pesticides on soil and on the dissolved organic matter in water. 

Table 6 Comparisons of environmental half-lives (in years) of organochlorine pesticides in gas phase, precipitation, and dissolved phase in Lake Ontario, during 1992-2000 ...

Chlorinated hydrocarbon insecticides, when dissolved in oil or other lipid, are readily absorbed by the skin and alimentary canal. Although methoxychlor is slowly metabolized to a small extent by pathways similar to those of DDT, the major pathway is by O-demethylation and subsequent conjugation. Methoxychlor has been detected in the blood of agricultural workers. All organochlorines are likely to be excreted in the milk of lactating women. Methoxychlor is excreted mainly in feces, and to a lesser extent in urine. 

Pigs were fed for 14 weeks with feed enriched with organochlorine pesticides (OCPs). The pesticides used were pure calibrants of HCB, a-HCB, b-HCB, y-HCB, heptachlor, dieldrin, endrin, and p,p -DDT. Quantities of 100 mg to 1.8 g of these compounds were weighed and dissolved in hexane/maize oil. For b-HCB, acetone/maize oil was used. The desired amounts were calculated using maximum levels for fat applicable in EC... 

We now seek to relate the concentration of solute that remains in the aqueous phase after pLLE to the original concentration of solute, Cinitiai-For example, a groundwater sample that contains dissolved organochlorine pesticides such as DDT can be mathematically related to the partitioned concentrations in both phases according to... 

Like other chemicals, organochlorines occur in seawater in a continuum of dissolved, colloidal and discrete particulate forms Gustafsson and Gschwend, 1997). Operationally, dissolved and particulate suspended forms may be distinguished on the basis of separation techniques such as filtration or centrifugation. Ihe separation may depend on size and density of the particles it may also depend on the composition of the suspension. For instance, particles smaller than the nominal filter pore size are retained on a clogged filter. 

Obtain organochlorine and carbamate pesticide standards from a commercial source such as Polyscience Corp. or ChemService (Westchester, PA). Obtain standards of phorate and its metabolites from the manufacturer, American Cya-namid Co., Princeton, NJ. Prepare individual and mixture solutions at a level of 1 J,g/)il by dissolving 25 mg of each compound in 25 ml of solvent. For the study of chlorinated pesticides, prepare individual solutions and a mixture of heptachlor, endosulfan (Thiodan), heptachlor epoxide, lindane, dieldrin, and dico-fol (Kelthane) in hexane. For organophosphate pesticides, use phorate and its metabolites phoratoxon, phorate sulfoxide, and phoratoxon sulfoxide in ethyl acetate. For carbamates, use 3-keto carbofuran (a metabolite of carbofuran), carbaryl, and metalkamate (Bux) in ethyl acetate. 

O. Wurl, J.P. Obbard, and P.K.S. Lam, Distribution of organochlorines in the dissolved and suspended phase of the sea-surface microlayer and seawater in Hong Kong, China, Mar. Pollut. Bull. 52 (2006b) 768-777. 

Organic wastes can be oxidized in supercritical water, taking advantage of the ability of supercritical fluids to dissolve organic compounds (see Section 22.4). Wastes are contacted with water and the mixture raised to a temperature and pressure required for supercritical conditions for water. 0 gen is then pumped in sufficient to oxidize the wastes. The process produces only small quantities of CO, and no SO2 or NOx. It can be used to degrade PCBs, dioxins, organochlorine insecticides, benzene, urea, and numerous other materials. 

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