Such a
magnitude of toxicity to fish was similar to that of the
cell-free filtrate stored in the dark under refrigeration at
48C (dark lab control) in the laboratory during the
natural sunlight study period: an acute 24 and 48-h
LC50 value of 14.03% (10.29–19.13%) filtrate was
determined. Results from the time-to-death study
showed that the 100% treatment levels of both laboratory
and field dark treatments all organisms were dead
within 3 h. In the 25% filtrate treatment level for both
dark treatments, 50% mortality (LT50) was calculated at
2.3 h (95% CI: 1.37–3.84 h; Fig. 2).