A selective historical review of congener-specific human tissue measurements as sensitive and specific biomarkers of exposure to dioxins and related compounds.

Abstract

Estimating internal exposure or dose of dioxins and related chemicals such as dibenzofurans and dioxinlike polychlorinated biphenyls is relatively straightforward in laboratory animals because a known dose is given and the amount absorbed can be measured. In wildlife, direct tissue measurement and measurement of environmental samples have both recently been used to estimate exposure. Until recently, human studies used only indirect indicators such as skin lesions to qualitatively estimate exposure to these chlorinated organic compounds. Environmental measurements have also sometimes been used to estimate human exposure. Dioxins in human tissue were not measured until the 1970s, when 2,3,7,8-tetrachlorodibenzo-p-dioxin was measured in mothers' milk; congener-specific measurement of dioxins and dibenzofurans in tissues (blood, milk, and adipose tissue) of the general population and exposed workers was first performed in the United States in the 1980s. Measurement in a sensitive and specific fashion of the 17 toxic dioxin and dibenzofuran congeners currently found in human tissue from industrial countries began in the 1980s. The use of known chemical standards, capillary columns, high resolution gas chromatography and mass spectrometry (GC-MS) has now become relatively common. GC-MS analysis of blood is currently accepted as the gold standard for estimating human exposure to dioxins. However, analyses are still costly and time consuming, and worldwide there are few qualified laboratories. There is currently a lack of knowledge concerning kinetics at higher and lower exposure levels for most of the toxic dioxin congeners and of levels in target tissues of concern.ImagesFigure 1Figure 2Figure 3Figure 4Figure 5

Polychlorinated dibenzo-p-dioxins and dibenzofurans in blood and breast milk samples from residents of a schistosomiasis area with Na-PCP application in China

“…In the 50 individual primipara breast milk samples, PCDD/F concentrations ranged from 0.43 to 11.4 pg g À1 lipid WHO-TEQ, with a mean value of 5.5 pg g À1 lipid WHO-TEQ. The subjects had lower total WHO-TEQ levels in breast milk than those reported in previous studies conducted in the general population at a comparable age (Johansen et al, 1996;Calvert et al, 1998;Schecter, 1998;Kiviranta et al, 2002;Wang et al, 2004). Possible reasons may be that (1) the predominant OCDD congener has little contribution to the total TEQ levels, and (2) the subjects have different dietary habits.…”

Levels and congener distributions of PCDDs, PCDFs and dioxin-like PCBs in environmental and human samples: a review

“…Infants are exposed to PCDDs, PCDFs, and dioxin-like PCBs prenatally and via breast milk (Päpke 1998;Schecter 1998;Schecter et al 1998;Wang et al 2004). In the most industrialized countries, concentrations of PCDD/Fs and other organochlorine compounds have been regularly monitored in human milk and a rather large database on the general population contamination is currently available.…”

Analysis of Breast Milk to Assess Exposure to Chlorinated Contaminants in Kazakhstan: Sources of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) Exposures in an Agricultural Region of Southern Kazakhstan

“…ronmentai hormones." For PCDDs/PCDFs, contaminant concentrations in breast milk (8,14, 26,27) and human health effects (14,28-30) have been recently reviewed and include, for TCDD, cancer (14,31-40) and altered infant sex ratio (41). ed contaminants have estrogenlike activities, whereas the dioxinlike chlorinated com?…”