La. Warren et Ap. Zimmermann, SUSPENDED PARTICULATE GRAIN-SIZE DYNAMICS AND THEIR IMPLICATIONS FOR TRACE-METAL SORPTION IN THE DON RIVER, Aquatic sciences, 56(4), 1994, pp. 348-362
Citations number
37
Categorie Soggetti
Water Resources",Limnology,"Marine & Freshwater Biology
We examined particle size distributions of suspended particulate matte
r (SPM); physical and environmental influences on the observed distrib
utions; and relationships between particle size and geochemical partit
ioning of metals, over the fall and winter period in a small urban riv
er (Don River, Toronto, Ontario, Canada). For this dataset, the majori
ty of particles (80%) in suspension were less than 10 mu m in size. In
addition, while total SPM concentrations showed a positive trend with
increasing discharge (Q); the proportions of particles found within g
iven size classes were independent of both SPM concentration and Q. Te
mperature was the only measured environmental variable related to the
particle concentrations within size classes. As water temperature incr
eased, the concentration of particles in the smallest size class (1-4
mu m) decreased, while the concentration of silt and/or algae sized pa
rticles (10-50 mu m) increased. Increasing water temperatures may prom
ote bacterial attachment to particles and their subsequent flocculatio
n into larger sized particles. Decreasing concentrations of leachable
(most labile) Cd, Zn and Mn were associated with increasing concentrat
ions of the largest particles (70-150 mu m) in suspension. In contrast
, higher reducible (oxides) associated concentrations of Cd, Zn and Mn
occurred with increasing concentrations of smaller particles (1-10 mu
m) in suspension. Both of these trends are speculated to reflect the
importance of particle surface area for metal sorption reactions.