Soil Quality Criteria for Environmental Pollutants

Abstract

The assessment of soil quality regarding chemical pollution has been mainly covered through the development of soil quality standards (SQSs). The soil quality, measured in terms of the level or degree of contamination, is assessed by comparing the concentration of the relevant pollutants in the soil and the threshold values established for each chemical or group of chemicals. SQSs are nowadays developed using adapted risk assessment methodologies. The process includes three main components: exposure assessment, effects assessment, and risk characterization. The exposure assessment determines the exposure level for the different potentially exposed organisms, named as ‘the receptors,’ to the chemicals of concern through all the possible exposure routes. The environmental effect assessment determines the toxicological profile of the chemical substance to a set of selected organisms representing the potentially exposed receptors, and extrapolates the information for setting where exposure concentrations are not expected to produce relevant adverse effects. Usually, risk characterization is the final phase of the risk assessment process, where data from the effect and the exposure assessments are compared to determine the actual risk of potentially exposed organisms. For SQSs setting, risk assessment is applied in a different way, as it is used for determining the exposure level (soil concentration) associated with a preestablished level of risk, instead of the actual level of risk. Currently, soil quality criteria are targeted for including biological tools together with substance-specific SQSs. Thus, toxicity assays performed with environmental samples taken from the site and biomonitoring data are combined with the chemical analyses in the soil characterization. This article presents the development of SQSs for the protection of the ecosystems and the use of biological tools as a complementary method for assessing soil quality.