Prevention values for copper (low tier approach) in subtropical acidic soils

Area of Science:

• Environmental toxicology
• Soil science
• Ecotoxicology

Background:

• Copper is an essential trace element vital for plant and animal metabolism.
• Anthropogenic activities like agriculture and mining release copper, posing environmental risks.
• Brazilian legislation uses Prevention Values (PVs) as critical environmental limits for soil trace elements.

Purpose of the Study:

• To establish copper Prevention Values (PVs) for Cambisol and Nitisol, subtropical soils.
• To address the lack of pedological richness consideration in federal PV derivation.
• To assess the ecotoxicological impact of copper on diverse soil organisms.

Main Methods:

• Conducted reproduction assays following ISO guidelines.
• Utilized key soil invertebrates: earthworms (Eisenia andrei, Perionyx excavatus), enchytraeids (Enchytraeus crypticus, Enchytraeus bigeminus), and springtails (Folsomia candida, Proisotoma minuta).
• Determined species sensitivity and calculated EC50 values in Cambisol and Nitisol.

Main Results:

• Organism sensitivity varied, with greater sensitivity observed in Cambisol.
• Earthworms, particularly Perionyx excavatus, exhibited the highest sensitivity (EC50 values: 67.83 mg kg⁻¹ in Cambisol, 264.96 mg kg⁻¹ in Nitisol).
• Springtails demonstrated the lowest sensitivity to copper contamination.

Conclusions:

• The study highlights the necessity of including diverse ecological groups in ecotoxicological assessments.
• Derived PVs (346.74 mg kg⁻¹ for Nitisol, 134.05 mg kg⁻¹ for Cambisol) suggest the federal PV (60 mg kg⁻¹) is protective for these soils.
• Further research is needed on other subtropical soils due to varying properties influencing copper bioavailability and toxicity.