Suspended sediment and bedload discharges in sand-bed rivers shape semi-arid landscapes and impact sediment delivery from these landscapes, but are still incompletely understood. Suspended sediment and bedload fluxes of the intermittent Exu River, Brazil, were sampled by direct measurements. The highest suspended sediment concentration observed was 4847.4 mg L^-1 and this value was possibly associated with the entrainment of sediment that was deposited in the preceding year. The bedload flux was well related to the stream power and the river efficiently transported all available bedload with a mean rate of 0.0047 kg m^-1 s^-1, and the percentage of bedload to suspended sediment varied between 4 and 12.72. The bed sediment of Exu River was prone to entrainment and showed a proclivity for transport. Thus, sand-bed and gravel-bed rivers of arid environments seem to exhibit the same mobility in the absence of armour layer. Editor D. Koutsoyiannis; Associate editor B. Touaibia Citation Cantalice, J.R.B., Cunha Filho, M., Stosic, B.D., Piscoya, V.C., Guerra, S.M.S., and Singh, V.P., 2013. Relationship between bedload and suspended sediment in the sand-bed Exu River, in the semi-arid region of Brazil. Hydrological Sciences Journal, 58 (8), 1789–1802.

Metal concentrations in suspended sediments of one of the most polluted rivers in Brazil were measured. Concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined by inductively coupled plasma while Hg and As were analyzed with hydride generation flow injection atomic absorption spectroscopy. Contamination of As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn was assessed using pollution indices, ecological risk assessment, statistical multivariate techniques and comparison with sediment quality guidelines. Suspended sediments of the upstream portion of the Ipojuca River are moderately contaminated, especially with Mn and As. On the other hand, sediments of the downstream section are highly contaminated, mainly with Zn, Pb, and As. Furthermore, the mean Ei (potential ecological risk) values of Pb and As showed considerable ecological risk in the downstream cross section. The comparison of our data with sediment guideline values indicated that the concentrations of Mn and Pb in the upstream section of the Ipojuca River pose a risk to sediment-dwelling organisms, while Pb and Zn are the metals of concern in the downstream section.