Polychlorinated biphenyls tissue distribution

McCormack KM, Melrose P, Rickert DE, et al. 1979. Concomitant dietary exposure to polychlorinated biphenyls and polybrominated biphenyls Tissue distribution and arylhydrocarbon hydroxylase activity in lactating rats. Toxicol Appl Pharmacol 47 95-104. 

Knickmeyer, R. and H. Steinhart. 1989. On the distribution of polychlorinated biphenyl congeners and hexachlorobenzene in different tissues of dab (Limanda limanda) from the North Sea. Chemosphere 19 1309-1320. 

The polychlorinated biphenyls (PCBs) have been used commercially since 1929 as dielectric and heat exchange fluids and in a variety of other applications. The presence of PCBs in human and wildlife tissues was first recognized in 1966. Investigations in many parts of the world have since revealed widespread distribution of PCBs in the environment, including remote areas with no PCB production or use. There is evidence that the major source of PCB exposure in the general environment is the redistribution of PCBs previously introduced into the environment. It is believed that large bodies of water, such as the Baltic Sea and the Canadian Great Lakes, may... 

Harju, M. Bergman, A. Olsson, M. Roos, A. Haglund, P, Determination of atropisomeric and planar polychlorinated biphenyls, their enantiomeric fractions and tissue distribution in grey seals using comprehensive 2D gas chromatography J. Chromatogr. A 2003,1019, 127-142. 

Covaci, A. Gheorghe, A. Schepens, P., Distribution of organochlorine pesticides, polychlorinated biphenyls and a-HCH enantiomers in pork tissues Chemosphere 2004, 56, 757-766. 

Ishaq R, Karlsson K, Naf C (1999) Tissue distribution of polychlorinated naphthalenes (PCNs) and non-ortho chlorinated biphenyls (non-ortho PCBs) in harbor porpoises (Phocoena phocoena) from Swedish waters (manuscript... 

Tissue-to-blood Distribution Coefficients for Parent Polychlorinated Biphenyls (R) and Metabolites (R )... 

Allen JR, Norback DH, Hsu IC. 1974b. Tissue modifications in monkeys as related to absorption, distribution, and excretion of polychlorinated biphenyls. Arch Environ Contam Toxicol 2 86-95. 

Curley A, Burse VW, Grim ME, et al. 1971. Polychlorinated biphenyls Distribution and storage in body fluids and tissues of Sherman rats. Environ Res 4 481-495. 

Because of their once widespread use in electrical equipment, as hydraulic fluids, and in many other applications, polychlorinated biphenyls, PBCs (see Chapter 14) became widely distributed, extremely persistent environmental pollutants in the Asian region. PCBs have a strong tendency to undergo bioaccumulation in lipid tissue. More details on the toxicological features of PBC will be discussed in Chapter 14. 

Sanders M, Haynes BL. 1988. Distribution pattern and reduction of polychlorinated biphenyls PCB in bluefish Pomatomus-saltatrix (linnaeus) fillets through adipose tissue removal. Bull Environ Contam Toxicol 41 670- 677. 

Toxicants that are ingested generally are absorbed through the small intestine walls and are transported to the liver. The liver is the main site of toxicant metabolism and is where some poisonous substances are converted to less toxic forms more readily eliminated from the body whereas other substances are converted to toxic species. Toxic species are distributed around the body by the blood and lymph system, which can lead to systemic poisoning at sites remote from the entry of the substance into the body. Bone and adipose tissue (fat) are major sites of storage of toxicants. Bone accumulates heavy metals including lead and some radioactive materials, especially strontium-90, which biochemically behaves like calcium. Radioactive iodine accumulates in the thyroid and can cause thyroid cancer. Lipophilic toxicants, such as polychlorinated biphenyls (PCBs), that are poorly soluble in water tend to accumulate in adipose tissue. 

How a chemical is distributed in the body affects the rapidity of its elimination. Chemicals that are distributed in body water are more immediately accessible to the bloodstream and hence are more available for elimination by the kidneys and the liver As their blood concentration falls as a result of elimination, water-soluble chemicals diffuse out of body water and back into the bloodstream. On the other hand, chemicals that are distributed in fat or bone tend to be less immediately accessible to the bloodstream, and the time required for their elimination tends to be longer. Indeed, fat and bone have the potential to act as internal somces of low-level exposme over time as the concentration of a chemical builds up in these tissues. Examples are lead, which tends to be sequestered in bone, and persistent organic pollutants (POPs) Uke dioxin and polychlorinated biphenyls (PCBs), which tend to be sequestered in fatty tissue. These and other chemicals may persist in the body for months or years. 

The mammary barrier is less distinct than the other two discussed. There is no anatomical feature that prevents chemicals from entering breast tissue or breast milk. Instead, the breast is primarily composed of fatty materials and many small blood vessels. Therefore, only fatty chemicals will tend to be distributed to the breasts. Chemicals that are very lipid-soluble and have very low water solubility, like dioxin and some polychlorinated biphenyls (PCBs chemicals that historically were used in transformers), will be preferentially stored in fatty tissues like the breasts. If a woman is breast-feeding, the chemicals stored in the breasts could be transferred to the infant in the breast milk. 

---