A systematic review evaluating mercury contamination in Polychaetes.

Area of Science:

• Environmental Science
• Marine Biology
• Ecotoxicology

Background:

• Mercury (Hg) is a persistent, toxic contaminant with significant biomagnification potential.
• Polychaetes are crucial benthic invertebrates in marine food webs and potential bioindicators of mercury contamination.
• Understanding mercury dynamics in polychaetes is vital for ecological risk assessment and pollution management.

Purpose of the Study:

• To systematically review and synthesize global data on mercury and methylmercury accumulation in polychaetes.
• To evaluate methodological practices and ecological factors affecting mercury bioaccumulation in these organisms.
• To identify limitations and propose improvements for using polychaetes in mercury biomonitoring.

Main Methods:

• Systematic literature review of 49 studies from diverse ocean regions, countries, and Antarctica.
• Analysis of data from 21 polychaete families, considering total mercury (THg) and methylmercury (MeHg) concentrations.
• Evaluation of factors including feeding guilds, sample handling, tissue selection, and data reporting.

Main Results:

• Nearly 50% of reported THg concentrations in polychaetes surpassed the EQS-Biota threshold (110 μg/kg dw).
• Feeding guilds significantly influenced mercury bioaccumulation, with deposit/suspension feeders showing higher bioaccumulation factors (BAF) than carnivores/omnivores.
• Methodological inconsistencies across studies (e.g., depuration, tissue choice) impede cross-study comparisons.

Conclusions:

• Polychaetes frequently exhibit concerning levels of mercury contamination globally.
• Feeding guilds are key determinants of mercury bioaccumulation, suggesting a need for guild-specific monitoring approaches.
• Harmonized analytical protocols and expanded data are essential for effective polychaete-based mercury biomonitoring and risk assessment.