Immunotoxicity of PCBs (Aroclors) in relation to Great Lakes.

Abstract

Polychlorinated biphenyls (PCBs) are among the most widespread environmental pollutants and a prominent contaminant of the Great Lakes basin. Due to their resistance to biodegradation and lipophilic properties, PCBs bioaccumulate in fish tissues and in fish-eating humans. PCBs are also known to cross the placenta and to be excreted into the mother's milk, thus predisposing the infant to potentially adverse health effects. For example, a higher incidence of bacterial infections was reported for breast-fed infants born to mothers who consumed large amounts of Great Lakes fish compared to the incidence in control infants whose mothers ingested low amounts of fish. While data regarding the PCB-induced immunotoxic effects in humans are scarce, data derived from the use of experimental animals, including nonhuman primates, indicate that the immune system is a potential target for the immunotoxic effects of PCBs. Such studies have used the commercially available PCB mixtures alone. However, PCBs have the potential of partially antagonizing the effects of other structurally related compounds including the highly toxic dioxins, which are also present in small amounts in the Great Lakes. Thus, to fully evaluate the magnitude of the immunotoxic risk PCBs pose to humans, consideration should be given to investigations in which the interactive effects of PCBs are combined with other contaminants present in the Great Lakes.

Seafood consumption in pregnancy and infant size at birth: results from a prospective Spanish cohort

“…Not surprisingly, as it is not clearly established to be a risk factor for small size at birth, confounding by mercury also did not explain the associations observed, although seafood is an important source of this contaminant 59. Further study is needed to elucidate whether these relationships observed are causal and to identify the mechanisms involved, which might be related to other contaminants or contaminant mixtures 26 58…”

“…It has been suggested that adverse effects on fetal growth might be attributable in part to organic pollutants such as PCBs, for which relatively high levels have been reported for some types of seafood, including tuna, in Spain 21 55 56. Mechanisms linking such pollutants to fetal growth are not established27 but may involve effects on endocrine,23 28 thyroid57 or immune function 58. However, associations with SGA remained similar after adjusting for serum levels of several pollutants, suggesting that associations between may be more complex than a simple increase in the burden of these compounds.…”

Children’s white blood cell counts in relation to developmental exposures to methylmercury and persistent organic pollutants

“…The developing immune system appears to be highly sensitive to toxic effects, and experimental animal studies and in vitro assays have shown immunomodulatory effects of persistent organic pollutants (POPs), especially polychlorinated biphenyls (PCBs) [2-5], organochlorine pesticides (OCPs) [5-7], and perfluoroalkyl substances (PFASs) [8-10], as well as mercury and other metal compounds [11, 12]. These immunotoxicants are ubiquitous, most are persistent, and they are widely detected in children and adults from the general population [13].…”

Key Environmental Human Health Issues in the Great Lakes and St. Lawrence River Basins

“…For example, in addition to the described human health studies of children, other researchers have demonstrated in laboratory animal studies a number of comparable developmental and behavioral effects reported in children (e.g., Rice, 1997;Arnold et al, 1995;Tryphonas, 1995).…”