3.1. Nickel
Table 2 shows that Ni concentrations for different Spirulina
samples are highly variable. The Ni content ranged
between 0.211 and 4.672 mg/kg d.w. and the highest value
of Ni (4.672 mg/kg d.w.) was detected in sample S2.
Among the 25 samples tested, only three samples namely
S1, S21 and S22 had minimum level of Ni content as
0.211, 1.618 and 1.589 mg/kg d.w. respectively. Whereas
in the remaining 22 samples, high amount of Ni content
was detected ranging from 2.016 to 4.672 mg/kg d.w. The
order of Nickel concentration determined from the samples
was S3 >S4 > S5 >S20> S25> S15>S10> S7