PCDD/Fs and PCBs in Baltic herring during the 1990s

Area of Science:

• Environmental Chemistry
• Marine Biology
• Ecotoxicology

Background:

• Persistent organic pollutants (POPs) like PCDD/Fs and PCBs accumulate in marine organisms.
• Baltic herring are a key species in the Baltic Sea ecosystem, serving as an indicator for contaminant levels.

Purpose of the Study:

• To analyze levels of PCDD/Fs and PCBs in Baltic herring from different regions and time points.
• To investigate the correlation between contaminant concentrations and herring age.
• To assess temporal trends in POPs within Baltic herring populations.

Main Methods:

• Analysis of 1570 individual Baltic herring samples, pooled into 120 samples.
• Quantification of specific PCDD, PCDF, and PCB congeners using advanced analytical techniques.
• Calculation of toxic equivalents (TEQs) based on WHO guidelines.

Main Results:

• Strong positive correlations (r>0.8) were found between the age of herring and concentrations of specific PCDD/F congeners.
• Significant correlations (r>0.7) were observed between herring age and several PCB congeners.
• Higher concentrations of PCDD/Fs and PCBs (on a fresh weight basis) were detected in herring from the Gulf of Bothnia compared to the Gulf of Finland due to higher fat content.
• WHO-TEQ concentrations for PCDD/Fs ranged from 1 to 27 pg/g fw, and for PCBs up to 32 pg/g fw.
• No significant downward trend in contaminant concentrations was observed between 1993-1994 and 1999.

Conclusions:

• Herring age is a significant factor influencing the accumulation of PCDD/Fs and PCBs in Baltic herring.
• Geographical variations in fat content contribute to differing contaminant loads between the Gulf of Bothnia and Gulf of Finland.
• The persistent high levels of these pollutants indicate ongoing environmental contamination in the Baltic Sea.