Evidence-based logic chains demonstrate multiple impacts of trace metals on ecosystem services.

Area of Science:

• Environmental Science
• Ecotoxicology
• Ecosystem Services

Background:

• Trace metals exert significant, widespread impacts on ecosystems.
• Assessing these impacts solely on direct effects underestimates the total environmental burden.

Purpose of the Study:

• To develop evidence-based logic chains demonstrating the cascading effects of trace metal contamination on ecosystem services.
• To analyze the distinct pathways of copper in soils and mercury in freshwaters.

Main Methods:

• Constructed logic chains linking metal toxicity to ecosystem processes and services.
• Supported each chain link with published scientific evidence, noting the strength of support.
• Investigated copper pollution in soil ecosystems (134 chains) and mercury pollution in freshwater ecosystems (63 chains).

Main Results:

• Copper pollution in soils affects invertebrates, microbes, and plants, leading to complex impact pathways.
• Mercury pollution in freshwaters impacts food webs due to bioaccumulation.
• Both metals commonly affect human-use (food, fishing), non-use (amenity), and climate regulation (carbon sequestration) services.

Conclusions:

• An ecosystem services approach reveals underappreciated impacts of trace metals.
• Logic chains provide a robust method for assessing primary, secondary, and tertiary effects of metal pollution.
• Impacts extend to crop production, animal production, flood regulation, drinking water, and soil purification.