Impact of sediment releases on water chemistry and macroinvertebrate communities in clear water Andean streams (Bolivia)
Fossati, Odile; Wasson, Jean-Gabriel; Héry, Cécile; Salinas, Giovanna; Marín, Rubén
published: Mar 23, 2001
ArtNo. ESP141015101002, Price: 29.00 €
The impact of sediment releases due to road construction on water chemistry and invertebrate communities was studied in a clear water river system in the tropical humid Bolivian Andes. Eight sites (2 reference, 1 source and 5 impacted along the main river) were sampled during the 1997 low flow season. Suspended sediment concentrations exhibited a 500-fold increase downstream from the source of pollution compared to the reference site, but recovered to natural levels within 90 km in the main river. Suspended solids had only a minor influence on other chemical parameters, but had a clear negative effect on invertebrate density (200-fold decrease in abundance) and diversity (6-fold decrease in number of taxa) in the main river. The most affected insects were epibenthic gatherers (e.g. Ephemeroptera: Leptohyphidae, Coleoptera: Elmidae), swimmers (Ephemeroptera: Leptophlebiidae), and scrapers (Coleoptera: Psephenidae, Trichoptera: Hydropti lidae). These families are therefore considered to be the best potential bio-indicators of sediment release impact in clear-water Andean rivers.