Gw. Characklis et Mr. Wiesner, PARTICLES, METALS, AND WATER-QUALITY IN RUNOFF FROM LARGE URBAN WATERSHED, Journal of environmental engineering, 123(8), 1997, pp. 753-759
Water quality, metals concentration, and particle size distributions w
ere characterized in urban runoff. The distribution of metals in the m
acrocolloidal (0.45-20 mu m) and dissolved (<0.45 mu m) size fractions
was determined from samples taken under both storm and background con
ditions. Concentrations of particle number, organic carbon, suspended
solids, iron, and zinc increased during storms. The presence of zinc w
as highly correlated with organic carbon, each displaying significant
concentrations in both size fractions. Iron existed almost exclusively
in the macrocolloidal fraction. Differences in iron and zinc behavior
suggest that sedimentation is not always an effective technique for m
etals removal. Data from two storms followed throughout their duration
show individual materials eluting at different stages during storms.
These measurements also indicated potential relationships between the
zinc/organic carbon and iron/macrocolloid pairs. In addition, elevated
contaminant concentrations and increased flows during storms created
loadings equating to weeks dr months of background flow. Data also sho
wed no evidence of the ''first flush,'' which has been observed in man
y smaller watersheds. Results have implications for the design of larg
e-scale storm-water management strategies.