Tributyltin biomonitoring using prosobranchs as sentinel organisms

Area of Science:

• Environmental toxicology
• Marine biology
• Endocrinology

Background:

• Tributyltin (TBT) compounds are highly toxic xenobiotics causing various pathological reactions in animals.
• Virilization phenomena, such as imposex and intersex, in gastropod snails are sensitive indicators of TBT pollution.
• These effects can lead to female sterilization and reduced reproductive success in marine and freshwater species.

Purpose of the Study:

• To describe a reliable biomonitoring method for assessing environmental TBT pollution using virilization in prosobranch snails.
• To analyze the effectiveness of TBT legislation through extensive surveys.
• To investigate the mechanism of TBT-induced endocrine disruption.

Main Methods:

• Investigating imposex and intersex phenomena in gastropod populations.
• Utilizing biomonitoring indices to quantify TBT pollution levels.
• Conducting extensive surveys in France and Ireland to assess legislative effectiveness.
• Analyzing TBT's impact on steroid hormone biosynthesis, specifically estrogen production.

Main Results:

• Biomonitoring indices based on imposex and intersex provide precise, low-cost assessment of TBT pollution.
• Surveys in France and Ireland indicate a continuing threat of TBT to marine organisms despite legislation.
• TBT disrupts estrogen biosynthesis by inhibiting cytochrome P-450 dependent aromatase.
• Observed virilization phenomena are linked to this inhibition.

Conclusions:

• Virilization in gastropod snails is a reliable and cost-effective biomonitor for TBT pollution.
• Current TBT legislation's effectiveness is limited, with ongoing risks to marine ecosystems.
• TBT acts as an endocrine disruptor by inhibiting aromatase, leading to significant reproductive impairments in wildlife.