Persistence of polybrominated biphenyls (PBB) in human post-mortem tissue

Area of Science:

• Environmental Toxicology
• Human Health Risk Assessment
• Persistent Organic Pollutants

Background:

• Accidental contamination of animal feed with Polybrominated biphenyl (PBB) fire retardant in Michigan led to widespread human exposure.
• A significant portion of the Michigan population was exposed to PBBs approximately 10 years prior to this study.

Purpose of the Study:

• To evaluate the persistence and distribution of PBBs in human tissues a decade after the initial mass poisoning event.
• To quantify PBB concentrations in various tissues from autopsy cases in a high-exposure area.

Main Methods:

• Analysis of 196 tissue samples from 15 autopsy cases from the Grand Rapids area (high PBB exposure).
• PBB content determined using electron capture gas chromatography, measuring the hexabromobiphenyl peak.
• Detection limit for PBB concentration was 0.5 ng/g.

Main Results:

• PBBs were detected in 192 out of 196 analyzed tissue samples, confirming widespread persistence.
• Fat and fat-rich tissues exhibited the highest PBB concentrations, with perirenal fat showing the highest mean concentration (475 ng/g).
• Other tissues like adrenal, atheromatous aorta, and thymus had significant PBB levels, while most others had lower concentrations.

Conclusions:

• Polybrominated biphenyls (PBBs) remain present in human tissues 10 years post-exposure and are distributed across all examined tissues.
• The estimated PBB elimination half-time in fat is at least 7.8 years, suggesting lifelong persistence in contaminated individuals.
• This study highlights the long-term health implications of PBB exposure due to their enduring presence in the human body.