Nicolai-Alexeji Kummer

Effects of intercropping of oat (Avena sativa L.) with white lupin (Lupinus albus L.) on the mobility of target elements for phytoremediation and phytomining in soil solution

ABSTRACT This study aims to investigate how intercropping of oat (Avena sativa L.) with white lupin (Lupinus albus L.) affects the mobile fractions of trace metals (Fe, Mn, Pb, Cd, Th, U, Sc, La, Nd, Ge) in soil solution. Oat and white lupin were cultivated in monocultures and mixed cultures with differing oat/white lupin ratios (11% and 33% lupin, respectively). Temporal variation of soil solution chemistry was compared with the mobilization of elements in the rhizosphere of white lupin and concentrations in plant tissues. Relative to the monocrops, intercropping of oat with 11% white lupin significantly increased the concentrations of Fe, Pb, Th, La and Nd in soil solution as well as the concentrations of Fe, Pb, Th, Sc, La and Nd in tissues of oat. Enhanced mobility of the mentioned elements corresponded to a depletion of elements in the rhizosphere soil of white lupin. In mixed cultures with 33% lupin, concentrations in soil solution only slightly increased. We conclude that intercropping with 11% white lupin might be a promising tool for phytoremediation and phytomining research enhancing mobility of essential trace metals as well as elements with relevance for phytoremediation (Pb, Th) and phytomining (La, Nd, Sc) in soil.

Assessment of water-rock interaction processes in the Karst Springs of Makook Anticline (Kurdistan Region, Iraq) using Sr-isotopes, rare earth, and trace elements

This work characterizes the karst springs of the Makook karst system (Kurdistan Region, Iraq) in terms of geochemistry of Sr-isotopes, rare earth, and trace elements. The aim of the work is to better understand water-rock interaction by geochemical means. Sources of elements, correlation of flow rate and the geochemistry of carbonate aquifers, and effects of organic matter on the rare earth elements were investigated. Furthermore, the degree of karstification and the length of flow path were assessed. The 87Sr/86Sr ratio of two spring waters was similar to the ratio of rocks forming the aquifer, indicating that these rocks are their main and dominant Sr source. In the remaining six spring waters, the 87Sr/86Sr ratios were significantly higher than their corresponding aquifer rocks at the spring outlet and thus pointed to additional Sr sources. A temporal variation of 87Sr/86Sr in the Sarwchawa spring corresponds to flow rate changes. The chemical composition of the spring water reflects some important features of the chemical composition of their aquifers. Springs that stem from the Kometan aquifer (mainly limestone) are characterized by higher mineralization compared to springs that drained from dolomites of the Bekhme aquifer. Low to medium V2+, Rb+, P3+, and Si4+ contents in waters correspond to springs fed by limestone and dolomite aquifers, whereas higher concentrations of these elements reflect water from a marly limestone aquifer (Shkarta spring). The release of these elements is related to the clay fraction of this aquifer. In contrast, the highest concentrations of Ni2+, Se4+, Mo6+, SO42−, Sr2+, F¯, and Ba2+ were found in the spring fed by pure limestone but having the highest flow rate and the longest flow path. Therefore, these elements were enriched in the water due to longer interaction of the water with the rock. The temporal variation of REE concentrations in karst waters are controlled by flow, dissolved organic carbon (DOC), temperature, and redox reactions.