A comparison of plasmid distribution in sediment bacteria isolated from clean and naphthalene polluted sites

Bacteria were isolated from the sediment collected from one site above and one below the naphthalene-polluted discharge from a coking plant. Fifteen per cent of the isolates obtained from the effluent discharge site contained plasmids compared with 9·4% from the clean site. There was no significant difference in plasmid distribution, in the number or size distribution of plasmids per cell. The possible ecological significance of these results is discussed.