Table 2.

Tolerable daily intake (TDI), acute toxicity (LD50), and guideline values (GV) in drinking water, for cyanotoxins used in this study.

Cyanotoxin	Oral toxicity test μg/kg(b.w.)/day	TDIf μg/kg(b.w.)/day	LD50a μg/kg(b.w.) Intra-peritoneal mouse	GVb μg/l drinking water	References
CYN	NOAEL = 30c (mouse, 90 days)	0.03	200–2100	1 or 15	[22], [5]
MC-LR	NOAELc = 40 (mouse, 13 weeks)	0.04	25 to ∼1000	1 or 1.5	[23], [57], [27]
	LOAELd = 100 (pig, 44 days)	0.067
ATX-a	NOAELc = 510 (mouse, 7 weeks)	0.51	250	12.24	[2], [18]
BMAA	ND	ND	EC50e about 1 mM (118 μg/ml, in cells)	ND	[55], [45]
DAB	ND	ND	ND	ND	/

^aLD50: median lethal dose of a substance, or the amount required to kill 50% of a given test population.

^bGV: estimates made by assuming a human body wt of 60 kg; allocation factor, AF, of 0.8 and daily drinking water consumption, C, of 2 l. A guideline value (GV; μg/l water), to be used in formulating risk management strategies to strengthen drinking water safety throughout lifetime consumption, can be calculated as: GV = (TDI × body wt × AF)/C; where body wt is assumed to be 60 kg for a human adult and AF is the allocation factor: the proportion of the TDI via drinking water. Because some oral exposure may be via food or dietary supplements [13], an AF of 0.8 (80% of total intake) is assumed for drinking water and C = drinking water consumption per day, assumed to be 2 l for an adult. It should be noted that the values for GV in Table 2 were taken from the literature and were not calculated from the TDI values. In actual fact, the values for GV in the table are very different from those resulting from the use of the formula given above.

^cNOAEL: no-observed-adverse-effect-level.

^dLOAEL: lowest-observed-adverse-effect-level.

^eEC₅₀: effective concentration for 50% of organisms tested. ND: no data.

^fTDI: tolerable daily intake is derived by applying an uncertainty factor of 1000 to the NOAEL. ND: no data.