The tested samples are from different fluvial and estuarine environments (Paraná, Salado and the Amazon Rivers) and their sizes (SMD) range from 4 to 300 μm.
The relationship between SMD obtained with the two LISST-25X and the Malvern diffractometers gave a determination coefficient of R2 = 0.98. Compared to the Malvern instrument, used as a reference, it was observed that the LISST instruments tend to overestimate the measured SMD for diameters lower than 20 μm, and to underestimate the values of samples with larger diameters (> 20 μm). Aiming to obtain other characteristic diameters of the granulometric distribution from SMD measurements obtained with LISST-25X diffractometers, correlations between SMD and d10, d50 and d90, were established. The dependency of the measurement of sediment mass concentration obtained with LISST instruments, with the particle size, is also addressed.