Water samples were centrifuged for 15 min at 6000 g prior to the TAL assay. The endotoxin that remained in solution was referred to as ‘free-endotoxin’ and its activity, which was determined in water prior to centrifugation, was referred to as
‘total-endotoxin’. The activity of ‘bound-endotoxin’ was measured by subtracting the ‘free-endotoxin’ activity from the
‘total-endotoxin’ activity