Different carbon sources affect PCB accumulation by marine bivalves

Area of Science:

• Environmental Chemistry
• Marine Biology
• Ecotoxicology

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants.
• Land-based sources can contribute to marine contamination.
• Filter feeders and grazers can bioaccumulate contaminants.

Purpose of the Study:

• To evaluate Pampean creeks as land-based sources of PCB marine contamination.
• To analyze the role of creek carbon and nitrogen sources in PCB bioaccumulation.
• To assess PCB distribution in marine mollusks.

Main Methods:

• Analysis of PCB concentrations in surface sediments and mollusk tissues.
• Estimation of assimilated carbon and nitrogen sources using stable isotope analysis (C and N isotopes).
• Evaluation of PCB bioaccumulation in bivalve (Brachidontes rodriguezii) and limpet (Siphonaria lessoni).

Main Results:

• PCB concentrations in sediments ranged from 2.68 to 6.46 ng g⁻¹ (wet weight).
• PCB concentrations in mollusks ranged from 1074 to 4583 ng g⁻¹ lipid.
• A punctual PCB contamination source linked to a landfill area was identified.
• Mussel PCB bioaccumulation correlated with the uptake of non-marine carbon sources.

Conclusions:

• Pampean creeks, despite low flow, are significant vectors of PCB contamination to the marine environment.
• The carbon source assimilated by organisms is a crucial factor in understanding PCB bioaccumulation and distribution in coastal ecosystems.
• Non-marine carbon sources from creeks can enhance PCB bioaccumulation in marine invertebrates.