Baseline geochemical survey of the Riverina region of New South Wales and Victoria, Australia; concentrations and distributions of As, Ba, Br, Cd, Co, Cr, F, Ga, Mo, Sb, U and V compared to national and international guidelines

This study discusses element excesses and deficiencies in the regolith of the Riverina region, which may impact on plant, animal and human health. Top (0-10 cm depth) and bottom (c. 60-90 cm depth) overbank sediment samples were collected near the outlets of 142 catchments and the composition of the <180 mu m fractions determined. Total concentrations of As (0.8-159.8 mg/kg), Ba (189- 1263 mg/kg), Br (<1-89.5 mg/kg), Cd (<0.1-2.33 mg/kg), Cr (29-200 mg/kg), F (150-610 mg/kg), Ga (6.3-26.1 mg/kg), Sb (0.37-10.8 mg/kg), U (1.26-8.49 mg/kg) and V (31-145 mg/kg) are locally elevated above national and international guidelines and these elements therefore have potential for health concerns. Concentrations in at least half of the samples are above the guidelines for Ba, Cr, F, Ga and V. Based on total concentrations, most elements are unlikely to cause harm due to their low plant uptake and/or strong adsorption onto soil particles; however, Cd, V and U in particular require further investigation. Total concentrations of Co (2.96-34.2 mg/kg) and Mo (0.5-1.9 mg/kg) are potentially deficient in parts of the region and can be remedied with the application of appropriate fertilizers.