Table 2.

Calculation of the median lethal dose (LD50) of Fe3O4/Cs

Dose of Fe3O4/Cs (mg/kg body weight)	Number of animals	Number of dead animals	Z	d	(Z) × (d)
50	6	0	0	50	0
100	6	0	0	50	0
200	6	0	0	100	0
300	6	0	0	100	0
400	6	2	1	100	100
500	6	3	2.5	100	250
600	6	4	3.5	100	350
700	6	6	5	100	500

LD50 = 700 − (1200/6) = 700 − 200 = 500 mg/kg