Soil environmental carrying capacity and its spatial high-precision accounting framework

Area of Science:

• Environmental Science
• Soil Science
• Environmental Engineering

Background:

• Soil environmental carrying capacity (SECC) assessment is crucial for environmental sustainability but often overlooks human activity intensity and pollutant emissions.
• Existing methods lack spatial precision and effective early warning systems for human activity intensity.
• Assessing SECC requires integrating pollutant thresholds, input/output fluxes, and human activity impacts.

Purpose of the Study:

• To develop a spatial high-precision accounting framework for Soil Environmental Carrying Capacity (SECC).
• To establish a quantitative relationship between human activity intensity and pollutant emissions for improved SECC assessment.
• To provide an effective tool for early warning of human activity intensity in soil units.

Main Methods:

• Established a spatial Soil Environmental Capacity (SEC) model using pollutant thresholds and protection targets.
• Developed a spatial net-input flux model to quantify soil pollutant input/output.
• Integrated human activity intensity with pollutant emissions into the SECC model for spatial accounting.
• Applied the framework to assess SECC for copper production in a Chinese smelting area.

Main Results:

• Calculated average SECs for Cu, Cd, Pb, Zn, As, and Cr (e.g., Cu: 427.89 kg hm⁻²).
• Identified heavy metal concentrations and land-use types as key factors influencing SEC spatial distribution.
• Determined atmospheric deposition as the primary heavy metal input pathway, with high net-input fluxes in the southeast.
• Projected reduced average SECs under 50 years of current human activity intensity (e.g., Cu: 202.31 kg hm⁻²).
• Quantified the SECC for increased copper production capacity at 1.53 × 10⁶ t to maintain acceptable risk levels.

Conclusions:

• The proposed spatial SECC accounting framework offers high precision and effective early warning capabilities.
• Understanding the interplay between human activity, pollutant emissions, and soil capacity is essential for sustainable land management.
• The methodology provides a robust tool for managing industrial activities and their environmental impacts in vulnerable areas.