Tributyltin partitioning in sediments: effect of aging

Area of Science:

• Environmental Chemistry
• Geochemistry
• Marine Biology

Background:

• Tributyltin (TBT) is a persistent organic pollutant with significant environmental toxicity.
• Understanding the factors influencing TBT's fate in sediments is crucial for risk assessment.
• Sediment aging processes can alter the bioavailability and mobility of contaminants.

Purpose of the Study:

• To investigate the impact of aging on the partitioning and desorption of TBT in sediments.
• To determine how sediment properties, particularly organic carbon content, influence TBT aging effects.
• To assess the implications of aging for TBT's long-term behavior in contaminated environments.

Main Methods:

• Spiking of three sediment samples with contrasting properties with TBT (10 mg/kg).
• Aging of spiked sediments under sterile conditions for 1 to 84 days.
• Analysis of solid/pore-water partitioning and sequential desorption behavior (KD,app).

Main Results:

• Aging had minimal effect on TBT partitioning and desorption in sandy sediments (0.2% organic carbon).
• Substantial increases in TBT sorption were observed in sediments with higher organic carbon (2.6% and 4.8%).
• Apparent distribution coefficients (KD,app) doubled for aged, organic-rich sediments between 1 and 84 days.

Conclusions:

• Sediment aging is a critical factor affecting TBT sorption and desorption.
• The extent of aging effects on TBT is strongly dependent on sediment organic carbon content.
• Aging processes can lead to increased TBT sequestration, influencing its long-term environmental fate.