Assessing the impacts of the main river and anthropogenic use on the degree of metal contamination of oxbow lake sediments (Tisza River Valley, Hungary)

Abstract

Purpose Oxbow lakes, reaches that were cut off from a river during river straightening works, can accumulate during flooding metal-rich suspended sediments transported by a river from mining-impacted source areas and other anthropogenic sources. Additionally, the anthropogenic use of oxbow lakes may significantly impact the sediment-bound metal concentrations. The aim was to determine the dominating effect in the sediments' enrichment in heavy metals. Materials and methods We collected surface sediments (< 10-cm depth) from seven oxbow lakes once connected to the Tisza River (a transboundary river in Central and Eastern Europe). Four of the oxbows were located on the active floodplain, while three oxbows were at the reclaimed side (i.e., outside the flood defense levee). The sediment samples were subjected to total metal analyses (Cd, Co, Cr, Cu, Ni, Pb, and Zn) and sequential chemical extractions. Results and discussion Contamination indices (geoaccumulation index (Igeo) and pollution load index (PLI)) show a moderate but significant metal pollution of oxbow lakes situated on the active floodplain (I geo (Pb) 0.95-1.25, PLI 2.1-2.8) and an overall unpolluted to slightly polluted status of those at the reclaimed side (I geo (Pb) − 0.36-0.51, PLI 1.3-1.7). Additionally, the geochemical fractionation of the target metals showed that Cd and Zn were the most labile (Cd 29-48%, Zn 18-37% of nonresidual proportions), indicating their environmental significance. Conclusions Canonical discriminant analysis of the sediment-bound metal concentrations revealed the prevalent role of the river connection over the anthropogenic use in controlling the metal enrichment of oxbow sediments.

Perceived Risk of Fish Consumption in a Low Fish Consumption Country

“…Fish consumption may involve various physical risks including choking on bones, allergic reactions, spoiled fish and contaminants such as heavy metals [25,47,52]. An increase in consumers' perception of the physical risk of consuming fish may be expected as freshwater contamination becomes better detected [53][54][55][56]. While communication of potential physical risk associated with fish consumption (e.g., mercury) is important [57], Anual et al argue that consumers should be informed about contaminants in a way that equips them with the knowledge to more effectively manage the risk rather than resulting in decreased fish consumption [58].…”

Humic Acid Reduces the Available Cadmium, Copper, Lead, and Zinc in Soil and Their Uptake by Tobacco

“…Total metal concentrations alone cannot evaluate the metal's mobility, bioavailability, and environmental impact sufficiently [15]. The Community Bureau of Reference (BCR) sequential extraction method is widely used to determine the binding forms and the mobilities of metals in soils.…”

Geomorphology as a Driver of Heavy Metal Accumulation Patterns in a Floodplain

“…Examples of heavy metals on floodplains derived from mining have been described by many authors [6,[36][37][38][39][40] as has the use of metals to determine the timing and stratigraphy of floodplain alluvium [41][42][43][44]. Furthermore, there are studies on geomorphology as a driver of heavy metal accumulation in alluvial areas [13,[45][46][47][48][49][50], but their number is limited in relation to how the pattern of heavy metals alters among floodplain forms [51][52][53][54]. However, this is an important topic as different fluvial forms can generate very diverse accumulation patterns and a better knowledge of this can help to produce better maps of the distribution of metals.…”