Assessment of the Hazards of Polybrominated Biphenyls

Abstract

During their peak use period, PBBs represented under 1% of the total sales of fire retardant chemicals, and very probably would have escaped intensive study if they had not been mixed accidentally with animal feed preparations. Instead, international attention was drawn to PBBs by the state-supervised killing of over 35,000 cattle which had been contaminated with PBBs. Interestingly, low doses of PBBs exert a broad spectrum of toxicological, pharmacological, and biochemical effects despite low acute toxicity. These effects and the intensive bioaccumulation of PBBs derive from their structure and their consequent resistance of biotransformation and high solubility in fat. In rodents, PBBs are teratogenic, immunosuppressive, and potentially carcinogenic. In bovine, rodent, and avian species, PBBs reduce feed intake and induce mixed function oxidases of liver microsomes. The latter effect may be responsible for steroid level changes which underline hormonal toxicities observed in cows, mink, rats, and chickens. The effects of PBBs on humans are controversial, but data suggestive of immunological, skin, and liver disorders continue to accumulate. Concern about the clinical effects of PBBs is heightened by the knowledge that these compounds readily enter the fetus by crossing the placental barrier and can be transferred to newborn children after extensive passage into breast milk.

A dynamic multimedia environmental and bioaccumulation model for brominated flame retardants in Lake Huron and Lake Erie, USA

“…The hexabromobiphenyl content in BP-6 varied, ranging from 60 to 90% [17]. The content of individual PBB congeners in BP-6 was not precisely quantified, but BP-6 was known to contain isomeric tetrabromobiphenyls, pentabromobiphenyls, hexabromobiphenyls, heptabromobiphenyls, and an octabromobiphenyl [17]. Hass et al [24] reported 63% hexaBBs, 33% heptabromobiphenyls, and 4% pentabromobiphenyls in BP-6, according to their fractional areas in a gas chromatography-mass spectrometry analysis.…”

“…Of this amount, it was estimated that 273.0 metric tons were released into the environment. The hexabromobiphenyl content in BP-6 varied, ranging from 60 to 90% [17]. The content of individual PBB congeners in BP-6 was not precisely quantified, but BP-6 was known to contain isomeric tetrabromobiphenyls, pentabromobiphenyls, hexabromobiphenyls, heptabromobiphenyls, and an octabromobiphenyl [17].…”

“…Although production of PBBs at Michigan Chemical Corporation ceased in 1974, releases into air and water continued until 1977 [17]. From 1970 to 1977, 5,352 metric tons of FireMaster BP-6 were produced in Michigan [17].…”

“…Hexabromobiphenyl was the principal BFR constituent of FireMaster BP-6, a commercial product manufactured by Michigan Chemical from 1970 and 1974 [17,18]. HexaBB has a high octanol-water partition coeffienct (log K OW ¼ 6.4) and readily bioaccumulates in food chains [19].…”

Polychlorinated Biphenyls and Polybrominated Biphenyls

“…This is consistent with the tendency of PBBs to adsorb to soils with high organic content. No PBBs were detected in orchard grass or in carrot tops (Jacobs et al, 1976;Chou et al, 1978;DiCarlo et al, 1978).…”