Multiple organochlorine pollution and the thyroid.

Objective. Although the biological effects of major persistent organochlorinated pollutants (POPs) appear to be essentially similar, some effects which would be specific for certain substance cannot be excluded. We attempted to study the thyroid volume and thyrotropin level in the population living in the area with multiple pollution by polychlorinated biphenyls (PCBs) and pesticides (DDE and hexachlorobenzene - HCB). Methods. A total of 454 adults was examined within the pilot field survey in 1998. Among them were 237 males (age range 19-78 years, median 47) and 227 females (age range 19-78 years, median 48). Fifteen environmentally prevalent congeners of polychlorinated biphenyls and also p,p’-DDE (2,2’-bis(4-chlorophenyl)-1,1-dichloroethylene), p,p’-DDT (2,2’-bis(4-chlorophenyl)1,1,1-trichloro-ethane), hexachlorobenzene (HCB) as well as α -, β- and γ-hexachlorocyclohexane (HCH) were determined in serum by high resolution gas chromatography using microelectron capture detector and microcapillary column. Thyroid volume (ThV) was measured by real time sonography using the ellipsoid method with the aid of sonographic instrument Sonoline SI-400 (Siemens, Germany). The level of TSH was estimated by supersensitive immunoradiometric method using commercial kits by Immunotech (Marseille, France). Pearson’s correlation coefficients after logarithmic transformation of values and Spearman’s correlation coefficients were used for statistical evaluation. Results. Significant positive association (p 2000 (N=208) or >3000 (N=127) ng/g lipid, significant positive association (p 3000 ng/g lipid. When using Spearman’s correlation coefficients, significant negative association appeared between PCB and TSH (p<0.05), sum of organochlorines and TSH (p<0.05) and ThV and TSH (p<0.01). Conclusions. Although several significant positive and negative associations were found, this study, like several others, could not exactly define the participation level of individual POPs in their common toxic effects, but possibly contributed to the recognition and elucidation of some problems related to this task.