Temporal variability of solution Cd2+ concentration in metal-contaminated soils as affected by soil temperature: consequences on lettuce (Lactuca sativa L.) exposure

Abstract

The aim of this study was to assess how the solubility and the speciation of Cd in soil solution were affected over time by the soil temperature for three metal-contaminated soils. The changes of solution Cd concentration (either total or free ionic) and other physico-chemical parameters (e.g. pH, ionic strength, the concentrations of NO À 3 , SO 2À 4 , Ca, Mg and dissolved organic carbon) were monitored over a 28-day culture of lettuce (Lactuca sativa L.) in soils incubated at 10°C, 20°C or 30°C. The major result of this study was that Cd 2+ concentration greatly varied over time in soil solution. The Cd 2+ concentration declined over time in soil solution as did the concentration of cations that may compete for adsorption (Ca 2+ , Mg 2+ ). The rise in soil temperature primarily impacted on the concentration of Cd 2+ via promoting the microbial C-degradation and, thus, the complexation of Cd in soil solution. The integration of the temporal variations in Cd 2+ concentration through the calculation of the root exposure to solution Cd (E Cd ) provided a fairly close and robust prediction of Cd concentration in lettuce roots. The present work thus provided new insights on the fate of Cd in contaminated soils that may be relevant for predicting the root uptake of Cd.

Modelling the complexation of Cd in soil solution at different temperatures using the UV-absorbance of dissolved organic matter

“…Its impact has been extensively reported for Cd (e.g. Fotovat and Naidu, 1998;Sauve et al, 2000;Cornu et al 2008). Solution pH (Table 1) increased over the culture period by about 0.4 pH unit (P b 10 − 8 ).…”

“…Thereby, temperature can impact on the mobility of metals via modulating the soil microbial activity. This was clearly observed by several authors (Almas et al, 1999;Qureshi et al, 2003;Cornu et al, 2008). In the context of global climate change, the need to assess the impact of temperature on the mobility of metals in soil has become essential.…”

Evaluación de la toxicidad de metales pesados en dos suelos agrícolas de Colombia mediante bioensayos

“…El incremento de la toxicidad para el Cd en el andisol, periodo 2 de incubación, en el cual la concentración es menor, lo cual puede atribuirse a una posible desnitrificación (Cornu et al 2008), así como a un cambio del potencial redox, al aumento de la conductividad eléctrica de la solución, y que por aumento de la acidez, este metal pudo generar el desplazamiento de las sales de los sitios de intercambio de los coloides del extracto acuoso, generando la inhibición del crecimiento de las plántulas (Rodríguez-Serrano et al 2008). …”

Evaluation of the Effect of Gold Mining on the Water Quality in Monterrey, Bolívar (Colombia)

“…Likewise, the level of cadmium (Appendix A-Tables A1 and A2), also exceeded the minimum values established by the regulations for water for human consumption; studies have been reported where the exposure of L. sativa to this metal causes toxic and harmful effects that decrease its growth as the concentration of Cd, and thereby its adsorption, increases [59][60][61]. Just as the presence of heavy metals and cyanide has toxic implications in the plant and animal model, in the same way, it will affect the health of the human being [62,63].…”