SOMATIC AND F-SPECIFIC COLIPHAGES IN NEW-ZEALAND WASTE TREATMENT LAGOONS

Three coliphages (FRNA, FDNA and somatic) and three bacterial indicato rs (faecal coliforms, Escherichia coli and enterococci) were measured in four waste-treatment lagoons over 10 months. Two of the lagoons tre ated domestic sewage; the third, meat processing waste and the fourth, meat processing waste with a minor sewage component. In the meat proc essing lagoons the ratios of FRNA:FDNA were numerically large, due to very low counts of FDNA, and somatic coliphages generally outnumbered FRNA. Many of the FDNA plaques from meat processing lagoons were very small and were not confirmed on the F-plus strain, E. coli C 3000. In sewage lagoons all three coliphages were consistently present and FRNA usually outnumbered both FDNA and somatic coliphages. However, the ra tios of FRNA to the other two coliphages were not numerically large. R atios of coliphages, especially of FRNA:FDNA, seem a promising tool to distinguish between human and animal faecal pollution. Overall, there were no strong correlations between the bacterial indicators and the coliphages.