Halogenated persistent organic pollutants in Scottish deep water fish

Area of Science:

• Environmental Chemistry
• Marine Biology
• Toxicology

Background:

• Persistent organic pollutants (POPs), including chlorobiphenyls (CBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol-A (TBBP-A), are contaminants of global concern.
• Deep-water fish are potential bioaccumulators of these lipophilic compounds, posing risks to marine ecosystems and human consumers.
• The Rockall Trough is a deep-sea environment where contaminant levels in apex predators like deep-water fish warrant investigation.

Purpose of the Study:

• To quantify halogenated POPs and lipid content in liver and muscle tissues of three deep-water fish species from the Rockall Trough.
• To assess potential human health risks associated with the consumption of these fish based on measured contaminant levels.
• To compare contaminant concentrations against established environmental benchmarks like OSPAR Background Assessment Concentrations (BACs).

Main Methods:

• Analysis of chlorobiphenyls (CBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol-A (TBBP-A) in fish liver and muscle.
• Measurement of total lipid content in tissues to normalize contaminant concentrations.
• Calculation of Toxic Equivalent (TEQs) concentrations for 'dioxin-like' CBs and comparison with human health guidelines.

Main Results:

• Chlorobiphenyl (CB) concentrations exceeded OSPAR BACs in the liver of all three fish species (black scabbard, roundnose grenadier, black dogfish).
• Non-ortho CBs contributed minimally (<1%) to total 'dioxin-like' CB concentrations in fish liver.
• Polybrominated diphenyl ethers (PBDEs) were detected in both liver and muscle, while HBCD and TBBP-A were not detected; consumption of fish muscle posed no apparent health risk, but some roundnose grenadier liver samples exceeded safe limits.

Conclusions:

• Deep-water fish liver from the Rockall Trough accumulate significant levels of CBs, exceeding regulatory benchmarks.
• Human consumption of deep-water fish muscle is unlikely to pose a health risk from the measured POPs.
• Potential human health risks may exist from consuming roundnose grenadier liver due to elevated TEQ concentrations, necessitating further investigation into dioxins and furans.