Inhibition of bacterial enzyme activity and luminescence by urban river sediments

The toxicological and ecological effects of pollutants in urban river sediments were studied. The sediments were chemically or physically fractionated, using selective extractants to separate the effects of metal and organic contaminants, and subsequently tested for the inhibition of bacterial enzyme activity and luminescence. In many cases the enzyme activity of the sediment-dwelling bacteria was inhibited by metals. The variations in inhibition were attributed to differences in sediment complexation of, rather than bacterial community tolerance to, metals. Non-polar organic compounds significantly increased the toxicity of urban river sediments, and it is proposed that polyaromatic hydrocarbons from storm-water are an important source of sediment toxicity.