In vivo Immunotoxicity Assessment of Atrazine in two Economically-Important Marine Pelecypoda Species

Two commercially significant marine Pelecypoda species named Perna viridis (green mussel) and Paphia malabarica (short neck yellow clam) were exposed to different concentrations of Atrataf (commercial brand of atrazine available in India) in an acute toxicity test. The 96 h LC50 values of Atrataf to P. viridis and P. malabarica were 6.10 mg L-1, and 4.90 mg L-1 respectively. This study showed that there is a significant increase in mortality in both species as the dose and duration of Atrataf exposure are increased further, exposure to sublethal concentrations of the Atrataf. Moreover, following 14 days of exposure to sublethal doses of Atrataf, the immunotoxic potential of atrazine was examined by measuring viable haemocytes using the Tryphan Blue Exclusion Assay. After 14 days of exposure to the highest sublethal doses of Atrataf, the percentage of viable hemocytes decreased to 74.51 (Perna viridis) and 78.39 (Paphia malabarica), relative to the control. Since Haemocytes are the most critical cells in the immune system of Pelecypoda, any decrease in the hemocyte count will have a detrimental impact on the immune system activities. This is the first study of its kind study to investigate and report atrazine as a potential compound, which can induce immunotoxicity in Pelecypoda. The fact that the two studied species of Perna viridis and Paphia malabarica, are both commercially and ecologically important, their selection adds to the study’s significance.