Hydrochemical and sedimentological dynamics in a subtropical plain river: assessment by multivariate statistical analysis

SUAREZ, PAOLA A.; VEGA, MARISOL; PARDO, RAFAEL; ORFEO, OSCAR; GARCÍA CUESTA, JOSÉ LUIS; RONCO, ALICIA

Environmental Earth Sciences

Springer-Verlag

Lugar: Berlin; Año: 2016 p. 1 - 13

Abstract Understanding the transport dynamics of sedimentsand soluble components is critical when ecosystemscould be adversely affected. This study examined someenvironmental factors influencing the spatial and temporalvariations of water?sediment interactions in Negro River,northeast of Argentina, a subtropical plain fluvial systemwith anthropogenic influence. Samples of water and bottomsediments were collected from four sampling stations infour sampling campaigns spread over 2 years. Chemicalparameters, including pH, conductivity, major ions, concentrationof suspended sediments, extractable majorcations and particle size of sediments, were determined.The experimental data were interpreted by classicalhydrogeochemical methods and statistical methods. Multivariatestatistical tools were applied to reduce thedimensionality of the data set and to evaluate the relativeimportance of combinations of environmental variables onsediment dynamics. The results showed that the variabilityof the hydrochemistry and the sediment chemistry is controlledby longitudinal and seasonal factors, whereas differencesacross the river section were nonsignificant. Theconcentration of suspended solids and the abundance offine-grained materials in bottom sediments were inverselycorrelated with the concentration of some metals withagglutinant and coagulant properties in sediments. Thiscorroborates the presence of fine particle aggregates, alsoevidenced by classical grain-size analysis. Thus, particledisaggregation by chemical methods is not recommended,as it could lead to misinterpretation when the objective is toevaluate the dynamics of sediments in natural environments.This study highlights the importance of analyzingmultiple dimensions (spatial and temporal) to understandthe dynamics of fluvial sediments, especially in plainrivers.