Transfer of hexachlorobenzene (HCB) from mother to newborn baby through placenta and milk.

HCB was detected in all preparations of human placenta, maternal blood, milk, and cord blood. It was confirmed that HCB transferred from mother to fetus through the placenta. A significant linear correlation exists between the HCB concentration in placenta and that in cord blood. Therefore, the placental concentration of HCB is an accurate indicator of HCB contamination in pregnant women and in the newborn baby. It was decided that the commercial pesticides, PCNB and PCP, contained HCB at a concentration of about 0.7 and 0.4% of pesticides, respectively. The animals which consumed PCNB diet accumulated large amounts of HCB in lipid-rich tissues, especially in adipose tissue. On the other hand, PCNB was metabolized to methylthiopentachlorobenzene and bis(methylthio)tetrachlorobenzene. One of the main sources of HCB contamination in the general population in Japan may be derived from the commercial pesticides, PCNB and PCP.