Assessing the Efficacy of a Sediment Remediation Program Using Benthic and Pelagic Copepod Bioassays

Area of Science:

• Environmental Chemistry
• Marine Ecotoxicology
• Remediation Science

Background:

• Tributyltin (TBT) in antifouling paints caused significant marine pollution.
• Despite a global ban in 2008, TBT persists at toxic levels in high-traffic ports.
• A remediation program was implemented in a New Zealand port to address TBT and copper contamination.

Purpose of the Study:

• To evaluate the effectiveness of a marine remediation program using chemical analysis and copepod bioassays.
• To assess the reduction of tributyltin and copper concentrations post-remediation.
• To determine the impact of remediation on sediment and water toxicity to marine organisms.

Main Methods:

• Collected sediment and water samples from three locations within the port.
• Measured concentrations of organotin compounds and trace metals before and after remediation.
• Conducted benthic and pelagic copepod bioassays to estimate toxicity.

Main Results:

• Remediation successfully reduced acute toxicity in sediment samples.
• Post-remediation, tributyltin and copper levels decreased.
• Despite reduced acute toxicity, benthic copepod reproductive success remained impaired.

Conclusions:

• The combined approach of chemical analysis and bioassays effectively assessed remediation efficacy.
• While remediation reduced acute toxicity, chronic effects on marine life, like reproductive impairment, persist.
• Further strategies may be needed to fully mitigate the long-term ecological impacts of tributyltin contamination in ports.