Statistical method to evaluate the occurrence of PCB transformations in river sediments with application to Hudson...

Area of Science:

• Environmental Chemistry
• Environmental Science
• Toxicology

Background:

• Polychlorinated biphenyls (PCBs) are industrial compounds with varying environmental fates and toxicities based on congener structure.
• Changes in river sediment congener distribution can indicate transformation or transport processes.

Purpose of the Study:

• To quantify shifts in polychlorinated biphenyl (PCB) congener distribution in river sediments.
• To utilize the inherent relationships between PCB congeners in commercial mixtures (Aroclors) to detect environmental changes.

Main Methods:

• Employed correlated congener pairs (tracker pairs) that maintain constant relative proportions in Aroclors.
• Utilized relative abundances to eliminate bias from total PCB concentration.
• Compared Aroclor congener distributions with those found in Hudson River sediments using a database.

Main Results:

• Identified 276 pairs of correlated congeners from 95 individual congeners.
• Analyzed 218 tracker pairs in Hudson River sediments compared to Aroclors.
• Found conclusive evidence of shifts in congener proportions in 120 out of 218 cases.

Conclusions:

• Observed shifts in PCB congener distribution in Hudson River sediments are significantly greater than expected by chance.
• The methodology effectively detects environmental alterations in PCB composition.
• Relative congener abundance analysis is a powerful tool for assessing PCB fate and transport in sediments.