Dmj. Tubbing et al., BIOLOGICAL AND CHEMICAL ASPECTS OF DIFFERENCES IN SENSITIVITY OF NATURAL-POPULATIONS OF AQUATIC BACTERIAL COMMUNITIES EXPOSED TO COPPER, Environmental toxicology and water quality, 8(2), 1993, pp. 191-205
Bacterial populations from the main stream of the River Rhine and its
plume in the North Sea, the lower course of the rivers Meuse and Schel
dt, and various stagnant waters in the Netherlands were exposed to add
itions of copper in order to analyze differences in sensitivity. Growt
h rate, measured as thymidine incorporation rate, was generally more s
ensitive to copper(EC50:25-310 mug. L-1) than extracellular phosphatas
e activity, measured as hydrolysis of methylumbelliferin phosphate (EC
50: 179-3000 mug . l-1). The EC50 value for copper-inhibited growth wa
s correlated with the ambient total copper concentration, but such a c
orrelation was not evident for copper-inhibited enzymatic activity. Di
fferences in capacity of the waters to chelate an addition of 1000 mug
. L-1 of copper were estimated by measuring the inhibition of Photoba
cterium phosphoreum in the Microtox test. The growth rate of bacteria
in the upper, middle, and lower courses of the Rhine showed an increas
ing tolerance to copper, concurrent with increased input of copper and
increasing concentrations of suspended matter in the river. It is ind
icated in this study that part of the differences in sensitivity of ba
cterial communities is caused by the chemical conditions (i.e., by com
plexation), but biological differences in tolerance to copper, possibl
y induced by pollution, were also indicated.