Effects of Cadmium and Dimethoate on Some Biological and Biochemical Indices in Freshwater Green Algae, Spirogyra sp.

The present study investigates the influence of an organophosphorus pesticide, namely Dimethoate, and cadmium on biomarkers of the green alga, Spirogyra sp., in a 14-day experiment. For so doing, it has exposed Spirogyra sp. to 0.0, 100, 200, and 400 g L-1 of Dimethoate and/or 1 mg L-1 of cadmium chloride (CdCl2) to observe a reduction in chlorophyll a and b level in Spirogyra sp., exposed to 200 and 400 g L-1 of Dimethoate as well as algae treated with cadmium alone or in combination with Dimethoate. Levels of malondialdehyde (MDA) and total antioxidant in cells, as well as the activity of ascorbate peroxidase (APX) soar in Spirogyra sp., exposed to Dimethoate and/or cadmium (alone or simultaneously). Also Spirogyra’s exposure to cadmium and/or Dimethoate significantly increases catalase (CAT) activity. However, levels of carotenoids in Spirogyra sp., treated with both cadmium and Dimethoate, decline significantly, with no significant change found in catalase activity of Spirogyra sp., exposed to 100 and 200 g L-1 of Dimethoate, in comparison to the control group. However, CAT activity rises significantly in Spirogyra sp., treated with 400 g L-1 of Dimethoate. Cadmium can cause cytotoxicity in 1 mg L-1 concentration of the green algae (Spirogyra sp.). On the whole, investigating the biological and biochemical markers in Spirogyra sp., exposed to different concentrations of Dimethoate, has revealed some concentration-dependent toxicity. Furthermore, Dimethoate can synergistically increase toxicity and bioavailability of cadmium in Spirogyra sp.