Title : Growth Inhibitory Effect of Potassium dichromate with different pH on alga, Pseudokirchneriella subcapitata
In the present study, different concentration of potassium dichromate was studied with different pH viz., 6, 7, 8 & 9 in Bold basal medium on alga, Pseudokirchneriella subcapitata. The study met all the validity criteria. Maximum algal biomass of 163 times was recorded in pH 6 followed by pH 7 (116.82 times). The minimum biomass of 63.61 times was recorded at pH 8. The interesting result was found in average specific growth rate, at 0.26 mg/L concentration of potassium dichromate was NOEC for pH 6 & 7, while, NOEC for pH 9 was 0.64 mg/L concentration followed by pH 8 exhibited 1.6 mg/L concentration. The maximum growth inhibition of 111.53% was recorded at 10 mg/L concentration of pH 6 followed by 76.57% at 10 mg/L concentration of pH 8 and least inhibition of 33.90% was recorded in pH 7. The maximum yield inhibition of 100.22% was recorded at 10 mg/L concentration of pH 6 and least yield inhibition of 80.41% was recorded in pH 7. Based on the ErC50 (2.89 mg/L) and EyC (0.48 mg/L). Potassium dichromate was more toxic towards alga on pH 6 against algal yield and growth inhibition respectively. Conclusion: In the present study, toxicity of potassium dichromate was found to be dependent on the pH of basal medium. Potassium dichromate in alga medium at pH 6 was found to be highly toxic to alga and exhibit least toxic at 8 pH.