Dispersal and Attenuation of Trace Contaminants Downstream of the Ajka Bauxite Residue (Red Mud) Depository Failure, Hungary

• Published in: Environmental science & technology 2011-06, Vol.45 (12), p.5147-5155
• Main Authors: Mayes, William M, Jarvis, Adam P, Burke, Ian T, Walton, Melanie, Feigl, Viktória, Klebercz, Orsolya, Gruiz, Katalin
• Format: Article
• Language: English
• Subjects: Aluminum Oxide - chemistry; Applied sciences; Characterization of Natural and Affected Environments; Contaminated sediments; Continental surface waters; Creeks & streams; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Restoration and Remediation; Exact sciences and technology; Geochemistry; Geography; Geologic Sediments - chemistry; Hungary; Ions; Microscopy, Electron, Scanning; Minerals; Natural water pollution; Particle Size; Pollution; Pollution, environment geology; Principal Component Analysis; Rivers - chemistry; Sediment transport; Sediments; Structure Collapse; Trace Elements - analysis; Water Pollutants, Chemical - isolation & purification; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es200850y

This paper identifies the spatial extent of bauxite processing residue (red mud)-derived contaminants and modes of transport within the Marcal and Rába river systems after the dike failure at Ajka, western Hungary. The geochemical signature of the red mud is apparent throughout the 3076 km2 Marcal system principally with elevated Al, V, As, and Mo. Elevated concentrations of Cr, Ga, and Ni are also observed within 2 km of the source areas in aqueous and particulate phases where hyperalkalinity (pH < 13.1) is apparent. Although the concentrations of some trace elements exceed aquatic life standards in waters (e.g., V, As) and fluvial sediments (As, Cr, Ni, V), the spatial extent of these is limited to the Torna Creek and part of the upper Marcal. Source samples show a bimodal particle size distribution (peaks at 0.7 and 1.3 μm) which lends the material to ready fluvial transport. Where elevated concentrations are found in fluvial sediments, sequential extraction suggests the bulk of the As, Cr, Ni, and V are associated with residual (aqua-regia/HF digest) phases and unlikely to be mobile in the environment. However, at some depositional hotspots, association of As, Cr, and V with weak acid-extractable phases is observed.