Fish tissues for biomonitoring toxic and essential trace elements in the Lower Amazon

Area of Science:

• Environmental Science
• Ecotoxicology
• Analytical Chemistry

Background:

• Brazilian soils exhibit high concentrations of toxic elements, primarily mercury (Hg) and arsenic (As).
• Anthropogenic activities like agriculture, mining, and deforestation exacerbate the mobilization of these elements into aquatic ecosystems.
• The presence of toxic elements in aquatic environments poses a significant threat to environmental integrity and public health.

Purpose of the Study:

• To assess the feasibility of using freshwater fish tissues for biomonitoring toxic and trace element accumulation in the Lower Amazon, Brazil.
• To compare the biomonitoring potential of two fish species, Cichla temensis (Tucunaré) and Pterygoplichthys pardalis (Acari), and their tissues (liver and muscle).
• To investigate the influence of geological origins and anthropogenic activities on element deposition in fish.

Main Methods:

• Analysis of toxic and trace element concentrations in liver and muscle tissues of Tucunaré and Acari.
• Application of chemometric (multivariate) techniques to analyze trace element profiles.
• Comparison of element profiles from fish in different geographical and geological regions within the Amazon basin.

Main Results:

• Fish liver and muscle tissues, especially liver, are valuable for biomonitoring toxic and trace elements in the Lower Amazon.
• Tucunaré liver is optimal for monitoring food chain-accumulated elements (e.g., Hg), while Acari liver better reflects sediment-accumulated elements (e.g., As).
• Trace element profiles in fish varied significantly based on geographical origin, indicating distinct contamination sources and pathways.

Conclusions:

• Freshwater fish tissues, particularly liver, serve as effective indicators for biomonitoring toxic and trace elements in the Amazonian aquatic ecosystem.
• The accumulation of elements in fish is influenced by both geological soil characteristics and anthropogenic pressures.
• Biomonitoring using fish is essential for understanding and mitigating the risks posed by toxic elements to the environment and human populations in the region.