Leaching and transport of Zn through soil profiles in a seasonal river of a mining area in SE Spain

Abstract

Metal pollution can have adverse effects on human health but also on environment. Usually,risk is assessed on the basis of the total concentration of a trace metal in soils and sediments.Nevertheless, for checking the short and long-term true environmental impact of a traceelement, one of the most crucial factors to consider is its mobility. Leachability of metals fromsoils and sediments and, thus, their mobility, depends on several factors such as the soil typeon the basis of the parameters that affect metal interaction, the nature of the pollution in termsof the deposition and composition, and finally the environmental conditions that may lead toweathering. This study has been focused on the metal behaviour in some soil and sedimentprofiles placed in the river-bed of a seasonal river from a semiarid mining Mediterranean area,in SE Spain. Data from these analyses showed that a change of the environment conditionscould remobilise great amounts of Zn. In this sense, a change of acidic conditions could affectmainly to the lower drill. Meanwhile a change of reducing or oxidizing conditions can affect tomiddle and upper drills zinc remobilization. Middle stretch of the seasonal river shows a verydifferent behaviour in relation to zinc mobility, leachibility and distribution in soil profiles. Forthis river stretch, metal accumulation in the soil profile is higher, and leachibility risks forgroundwater could be higher. Besides, the lower stretch of the seasonal river show a specialmetal distribution because of the underlying materials are placed in the saturated zone(marine aquifer), what can determinate a horizontal, more than a vertical, metal flux