Integrative assessment of the biological responses elicited by metal pollution in the green garden snail, Cantareus apertus: Laboratory and field studies

Abstract

Abstract Sets of multiple biomarkers can be applied to achieve a comprehensive assessment of the biological impact of the chemical pollutants in contaminated soils. This approach requires the integration of diverse biomarker data into indices that provide early signs of ecosystem health disturbance. Within this context, this study aims at integrating multiple biomarkers in green garden snail, Cantareus apertus, on the basis of data obtained in preceding laboratory and field studies. In the laboratory, snails had been treated with dietary Pb, Cd and their mixture. Prompt (1 wk) and long-lasting (8 wk) response profiles were characterized and the biomarkers integrated as Integrated Biomarker Response (IBR/n) index. The response profiles were dose and treatment time dependent in quantitative terms and also qualitatively different along the treatment time. Yet, IBR/n was sensitive to provide early (1 wk) signs of health disturbance caused by the metals, and remained sensitive in the long term (8 wk). In the field study, soil metal pollution was investigated along a distance gradient from a main roadside. Both metal levels in the soil–plant-snail system and a set of biomarkers in snails were recorded. The IBR/n revealed that disturbance in soil ecosystem health was restricted to short distances (at 20 m but not at 150 m). Therefore, IBR/n was a suitable approach also in the complexity of the field. Moreover, together with the IBR/n index, recently developed indices of bioavailability (SET) and risk (ERITME) were applied in the field study. In accordance with the IBR/n index, the SET index also revealed an excess transfer of metals to snails limited to a short distance from the roadside and identified Cd as the priority target for soil pollution management. Likewise, the ERITME classification rank confirmed that environmental risk was the highest at 20 m away from the roadside and then decreased at 150 m and beyond. Therefore, the application of the IBR/n index together with existing indices of the bioavailability (excess transfer) and risk of contaminants represents a challenging approach for the integrated environmental risk assessment of contaminated soils.