Studies indicate that PCB exposure in the womb, even just one PCB dose on one critical day in the pregnancy, could cause changes in a child’s sense of smell, through changes in the olfactory parts of the brain. Additional studies show that PCBs accumulate in adults selectively in the nasal passages and olfactory organs, and alter the local chemistry, which may affect an adult’s sense of smell.
This area of research seems neglected in humans, perhaps because a partly-impaired sense of smell may not be obvious or as high a priority as learning disabilities or other effects.

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Study #10

PCBs reduced the DOPAC/domamine ratio in the olfactory tract
study used adult male rats
The effects of exposure to polychlorinated biphenyls on dopamine (51616) metabolism were studied in adult male Wistar-rats. The polychlorinated biphenyl mixture consisted of equal weights of Aroclor-1254 (11097691) and Aroclor-1260 (11096825) in corn oil. Animals received a single oral dose of the mixture at 0.5 milliliter per 100 grams body weight, resulting in a final dose of either 500 or 1,000 milligrams of polychlorinated biphenyls per kilogram body weight. Animals were sacrificed 1, 3, 7, or 14 days after treatment, and brains were rapidly removed to determine concentrations of dopamine and its major metabolites, 3,4-dihydroxyphenylacetic-acid (DOPAC) and homovanillic-acid (HVA) by high performance liquid chromatography with electrochemical detection. Dopamine and DOPAC concentrations in caudate decreased after exposure to polychlorinated biphenyls, as did HVA/dopamine ratios. Dopamine concentrations in the olfactory tract were unaffected, although DOPAC/dopamine ratios decreased. The authors conclude that the mature mammalian nervous system is sensitive to a brief exposure to polychlorinated biphenyls and that regional differences exist in the neurochemical sequelae of exposure to polychlorinated biphenyls. (Seegal et al, 1986)

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