Assessing element-specific patterns of bioaccumulation across New England lakes

Area of Science:

• Environmental Science
• Ecotoxicology
• Aquatic Ecology

Background:

• Trace element bioaccumulation in freshwater food webs is poorly understood.
• Identifying consistent patterns is crucial despite natural variability across lakes.

Purpose of the Study:

• To identify consistent bioaccumulation patterns of methylmercury (MeHg) and trace elements (As, Cd, Hg, Pb, Zn) in freshwater food webs.
• To evaluate current sampling strategies for their effectiveness in cross-lake and cross-study comparisons.

Main Methods:

• Measured MeHg and trace element concentrations in zooplankton and fish across seven New England lakes.
• Used N isotope analysis to estimate trophic positions.
• Reviewed 45 published studies on sampling approaches.

Main Results:

• Identified four consistent bioaccumulation patterns: MeHg biomagnification, Pb biodiminution, Zn higher in fish but with low variation, and As/Cd lower in fish.
• Zooplankton concentrations of As, Pb, Hg, and MeHg predicted fish concentrations.
• Current sampling methods are insufficient for robust cross-lake comparisons.

Conclusions:

• Despite variability, consistent trace element bioaccumulation patterns exist in freshwater food webs.
• Improved sampling strategies are needed to better understand trace element dynamics and drivers of elevated concentrations.