Bisphenol risk in fish exposed to a contamination gradient: Triggering of spatial avoidance

Area of Science:

• Environmental Toxicology
• Ecotoxicology
• Aquatic Ecology

Background:

• Bisphenol A (BPA) is a widespread industrial contaminant found in aquatic environments.
• Sublethal toxicity of BPA is expected at 500 μg/L, yet environmentally realistic concentrations are much lower (up to 0.41 μg/L).
• The impact of BPA contamination gradients on aquatic organism spatial displacement remains largely unstudied.

Purpose of the Study:

• To determine if BPA triggers an avoidance response in the freshwater fish Poecilia reticulata.
• To assess if BPA-driven avoidance occurs at environmentally relevant concentrations.
• To estimate population immediate decline (PID) considering avoidance and mortality.

Main Methods:

• Avoidance experiments were conducted in a seven-compartment system simulating a BPA contamination gradient.
• Poecilia reticulata (guppies) were exposed to varying BPA concentrations.
• Comparison with traditional acute toxicity tests to determine lethal and avoidance thresholds.

Main Results:

• BPA triggered a significant avoidance response in Poecilia reticulata.
• Avoidance of 50% of the population occurred at 0.20 μg/L BPA, four orders of magnitude lower than the lethal concentration (1660 μg/L).
• At environmentally relevant BPA levels, population immediate decline was primarily driven by avoidance.

Conclusions:

• Poecilia reticulata exhibits avoidance behavior at BPA concentrations below those causing sublethal effects.
• Avoidance is a critical endpoint for risk assessment, occurring at concentrations below safety thresholds set by international agencies.
• The study introduces a valuable, ecologically relevant approach for environmental risk assessment of contaminants like BPA.