The Effect of Estuary Type Suspended Solids on Survival of E. coli in Saline Waters

Abstract

The effect of estuary type suspended solids on E.coli inactivation has been examined in laboratory experiments. The work used artificial seawater, laboratory processed suspended solids and chemostat steady-state E.coli cultures to establish the effect of these physical/chemical parameters on the viability of an E.coli population. Initial E.coli concentrations were 5 × 103. 100ml−1, the temperatures employed were 10°C and 20°C, the suspended solids concentration range was 0 – l00mgl−1, salinity range 10 – 32%o, and the experimental vessels were completely shielded from light. The introduction of suspended solids at a low concentration (ie 5mgl−1) markedly increased the survival time of E.coli at the higher salinities (ie 32% o and 27%o). Suspended solids at higher concentrations (>12.5mgl−1) provided no additional increase in survival time. At low suspended solids concentrations (≤5mgl−1) decreasing salinity increased survival time; at higher suspended solids concentration (>12.5mgl−1) salinities in excess of a critical value, around 27%o, also increased survival times.