Blood dieldrin levels

Blood levels of aldrin in persons exposed to airborne aldrin in dwellings treated for white ants was investigated by Gun et al. (1994). The mean blood dieldrin (ppb or pg L-1) increased from 0.75, prior to treatment, to 1.2 3 months after treatment. 

Another major exposure route for humans is via contaminated food. For example, North America s Great Lakes, which are the largest body of freshwater in the world, are polluted with about 362 contaminants that were found in quantifiable amounts in the water, sediment, and biota (IJC 1983 USEPA 1994). The critical pollutants were identified as PCBs, DDT, dieldrin, toxaphene, mirex, methyl mercury, benzofa) pyrene, hexachlorobenzene, polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and alkylated lead. Some of these pollutants biomagnify in the aquatic food chain and can be detected in increased levels in cooked Great Lakes fish. Consequently, the blood serum levels of these chemicals are significantly increased in consumers of contaminated Great Lakes sport fish compared to people who do not eat such fish (Flumphrey 1983 Fiore et al. 1989 Sonzogni et al. 1991). 

FIGURE 5.6 Dieldrin intoxication in hnmans and its relationship to blood levels. The hatched area represents the sublethal effects seen at 15-30% of lethal threshold concentration in blood (after Jager 1970). 

Experimental animals exposed to sublethal doses of cyclodienes show a similar picture, with changes in EEG patterns, disorientation, loss of muscular coordination and vomiting, as well as convulsions, the latter becoming more severe with increasing doses (Hayes and Laws 1991). It is clear from these wide-ranging studies that a number of neurotoxic effects can be caused by cyclodienes at levels well below those that are lethal. In the human studies described here, subclinical symptoms were frequently reported when dieldrin blood levels were in the range 50-100 pg/L, an order of magnitude below those associated with lethal intoxication. 

Although endrin is a stereoisomer of dieldrin, it does not persist in the body as dieldrin does. The half-life of endrin in humans and animals is 2-6 days (Ert and Sullivan 1992). Thus, endrin is unlikely to accumulate in adipose tissue. There are reports of ingestion of bread contaminated with endrin which caused sudden convulsions in three persons. In one person, the serum level was 0.053 ppm 30 minutes after convulsion and 0.038 ppm after 20 hours. In the other 2 cases, no endrin was detected in the blood at 8.5 or 19 hours after the convulsions occurred (Proctor et al. 1988). 

In Australia, the most extensive set of data involves 4640 blood samples analysed for OCPs at the New South Wales Workcare Authority from 1987 to 1989. The vast majority of samples contained less than the occupational limits 50ppb (pg L-1) of dieldrin and less than 20ppb (pg L-1) of heptachlor. Of the 49 samples above the occupational limit 44 of these were from pest control operators (NHMRC, 1992). An earlier NSW study by Siyali (1972) compared whole blood levels of organochlorine insecticides from persons with and without industrial pesticide exposure. Levels of HCB, total DDT, dieldrin and HCH (BHC) were substantially higher in the exposed group, particularly for dieldrin. 

Tissues such as fat, blood or liver can be examined for residues of the more stable chlorinated hydrocarbon pesticides. In most cases these tissues are available as a result of elective survery, autopsy or biopsy. Exposure to DDT results in some storage of the parent compound in body fat. A large portion, however, is metabolized and stored as DDE (jJ). Aldrin and hepta-chlor are similarly transformed and stored as dieldrin and hepta-chlor epoxide. Levels of the urinary metabolite DDA have been used to assess exposure or body burden of DDT (10, 11, 12). Hexachlorobenzene and the various isomers of hexachlorocyclo-hexane are stored in fat as the parent compound but a small... 

Mustafa, M.D., Pathak, R., Tripathi, A.K., Ahmed, R.S., Guleria, K., Banerjee, B.D. Maternal and cord blood levels of aldrin and dieldrin in Delhi population. Environ. Monit. Assess. 171, 633-638 (2010)... 

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