Soil Quality Indices Based on Biological Properties to Assess Chemical Soil Degradation by Metal(loid)s

ABSTRACT

Soil quality assessments, rarely applied to contaminated soils with metal(loid)s, consider ecological topics such as multifunctionality, resistance and resilience of microbial communities to perturbations, in addition to ecosystem services. In this study, the effect of metal(loid) contamination was evaluated in soils based on physicochemical and biological properties at different distances from an industrial complex and a Cu smelter. From these properties, soil quality indices (SQIs) were tested to compare their sensitivity and relationship with metal(loid) contamination. Enzyme activities and the average well color development, obtained from the community-level physiological profile, were the most suitable soil quality indicators. These variables along with some physicochemical properties [e.g. total organic carbon, pH, and available metal(loid) contents] were selected to develop SQIs. Five SQIs were calculated, from which the Multifunctionality assessment and the Area_SQI were found to be suitable methods to develop SQIs due to their higher discriminant power and relationship with metal(loid) contamination compared to other SQIs. They were validated using data from the literature, and both showed decreasing values at higher levels of metal(loid) contamination. Although the Area_SQI represents an attractive approach due to its visualization and easy interpretation, the multifunctionality approach showed a stronger sensitivity to chemical degradation by metal(loid)s in soil and offered an easier and faster calculation alternative.

KEYWORDS:

• Soil health
• heavy metal contamination
• soil quality indicators
• soil biological properties
• MicroResp^TM

Acknowledgments

The authors would like to acknowledge the support of the ANID/FONDECYT/321075 and the ANID/FONDECYT/1170264 grants. P. Cornejo also thanks the support of ANID/FONDAP/15130015. Hendrik Sulbaran is grateful for the “Universidad Católica del Maule Doctoral Scholarship”, awarded by the Vice-Rectory for Research and Postgraduate Studies at the Universidad Católica del Maule, Talca, Chile.

Disclosure statement

The authors declare that they do not have conflict of interests that could have appeared to influence the work reported in this paper.

Additional information

Funding

The work was supported by the Agencia Nacional de Investigación y Desarrollo (ANID), Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT), projects 1170264 and 321075.