Is soil basal respiration a good indicator of soil pollution?

- SBR test presented good sensitivity in low organic-matter content and acidic pH soils.
- OC, pH, CaCO3, texture, and CEC are key factors in the pollution assessment by SBR.
- SBR test is not a good indicator of Pb, Zn and Cu pollution in highly carbonate soils.
- SBR test showed low sensitivity in As-polluted soils.

Metal(loid)s are common pollutants in soils, causing a significant toxicological risk to living organisms and to the ecosystems. Soil basal respiration (SBR) is broadly used as indicator of metal(loid) stress in polluted soils, although the correlation with toxicity gives in many cases contradictory results. In this paper, we study seven different soils with contrasting properties and with different pollution levels of As, Pb, Zn, and Cu to assess the influence of soil properties and contaminant concentration in the SBR response. In general terms, the SBR showed toxic effects in soils with low organic-matter content and acidic pH values. Low respiration rates were found in soils polluted with As even at very high contamination levels. According to our results, SBR is not a good indicator of pollution by Pb, Zn and Cu in soils rich in organic carbon or in highly carbonate soils. In As-polluted soils, SBR also showed a low sensitivity in all cases. Further studies are needed to assess the role of soil properties and the type of pollutant in the SBR tests.