Human tissues, chemical residues

Biomarkers of Exposure and Effect. Exposure to heptachlor and heptachlor epoxide is currently measured by determining the level of these chemicals in the blood or adipose tissue in living organisms (Curley et al. 1969 Klemmer et al. 1977 Radomski et al. 1968). This measure is specific for both heptachlor and heptachlor epoxide. Heptachlor epoxide is also a metabolite of chlordane, and thus its presence is not specific for exposure to heptachlor alone. However, in the absence of stable chlordane residues (e.g., nonachlor and oxychlordane), the heptachlor epoxide would most likely have been derived from heptachlor. Because heptachlor is believed to be converted rapidly in the body to heptachlor epoxide, it is impossible to determine whether the exposure was to one or the other of these two compounds. Heptachlor and heptachlor epoxide accumulate in adipose tissue and are released slowly over long periods of time. Therefore, it is not possible to accurately identify whether the exposure was recent or what the duration of exposure was. However, the ratio of heptachlor epoxide to heptachlor increases over time and therefore may be used as a biomarker of possible exposure to heptachlor. The sensitivity of the methods for identifying these compounds in human tissue appears to be only sufficient to measure background levels of heptachlor epoxide in the population. Additional biomarkers of exposure to heptachlor would be helpful at this time. 

LeBel GK, Williams DT. 1986. Pesticide and industrial chemical residues Determination of helogenated contaminants in human adipose tissue. J Assoc Off Anal Chem 69 451-458. 

The Biophysiologic Analysis of Chemical Residues in Human Tissues... 

The 1991 National Research Council report Monitoring Human Tissues for Toxic Substances recommended that any new program to assay chemical concentrations in tissues of the U.S. population be based primarily on analysis of blood. The use of blood permits sampling of a wider sector of the population, better comparison of exposed populations with national averages, repeat sampling of persons who have high tissue concentrations, and opportunities to follow chemical clearance with time. The 1991 report also advised analysis of adipose tissue (especially for persistent pesticides) that would provide continuity with previous studies and confirmation that a survey based on blood also detects important tissue residues of persistent chemicals (NRC 1991). 

In a review of 13 fatalities due to overdosage with ethchlorvynol, postmortem blood concentrations were in the range 14 to 400pg/ml (mean 119) (C. J. Rehling, Poison Residues in Human Tissues, in Progress in Chemical Toxicology, Vol. 3, A. Stolman (Ed.), New York, Academic Press, 1967, pp. 363-386). 

Human tissue plasminogen activator, purified, glycosylated, 527 residues purified from CHO cells. Eminase is a lyophilized formulation of anistreplase, the p-anisoyl derivative of the primary Lys-plasminogen-streptokinase activator complex (a complex of Lys-plasminogen and streptokinase). A p-anisoyl group is chemically conjugated to a complex of bacterial-derived streptokinase and human plasma-derived Lys-plasminogen proteins. 

Obtaining information on consumer and environmental exposure is even more difficult. No data base with sufficiently broad coverage of the chemicals has been developed. USDA s Meat and Poultry Inspection Monitoring Program and EPA s Pesticide Enforcement Management System are data bases that could be useful for assessing consumer exposure. The former provides analysis data on a limited number of pesticides, heavy metal, and drug residues in meat and poultry, whereas the latter has a small file on levels of pesticides and a few other chemicals identifted in human tissues. 

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