According to the hazard classification system for naturalwaters proposed
by Persoone et al. (2003), A1 and A2 should be classified as very
high acute hazard because a 100% effect level was reached in both test
algae and daphnia. Samples A3, A4 and A5 would be classified as high
acute hazard because the 100% effect level was reached in at least one
test. Likewise, although A9 was not toxic to algae, this sample caused
100% immobilization of the daphnia, and therefore it is also classified
as high acute hazard.