VARIATIONS OF ENVIRONMENTAL PARAMETERS AND ECOLOGICAL RESPONSE IN AN URBAN RIVER

Water and sediment quality deterioration in an urban river was assesse d during and after stormwater runoff and sewer overflow. Stormwater ru noff had a noticeable effect on continuous measurements of water quali ty in the urban river, oxygen sag and increased conductivity was a typ ical response. Sediment toxicity was found at sites directly exposed t o urban runoff, while concentrations of copper and lead exceeded sedim ent quality criteria. The enzyme activity of the sediment-dwelling bac teria was found to be more sensitive with inhibition downstream and up stream of urban discharge.