The article, entitled “Relationship of Blood Mercury Levels to Health Parameters in the Loggerhead Sea Turtle” by Day et al., (2007) aimed at investigating the threat of mercury as one of the pervasive environmental pollutants in loggerhead sea turtles (Caretta caretta). The rationale behind this study is that there was a need for a study that focuses on the presence of mercury in sea turtles and its toxic effects since immunosuppression is evident in diseased populations. Total Hg analysis, clinical chemistry and complete blood counts,lymphocyte proliferation: ex vivo THg exposure, incubation, lymphocyte proliferation: in vitro MeHg exposure, lysozyme activity, corticosterone and testosterone, statistical analysis, THg concentrations, the use of clinical blood parameters, and ex vivo lymphocyte were implemented to obtain results. Randomly selected free-ranging subadult and adult turtles that served as the research sample were examined from May 2001 to July 2003.To assess proliferative responses, lymphocytes were exposed in vitro to methylmercury. The authors found a positive correlation between blood mercury concentrations and hematocrit and creatine phosphokinase activity, but they also found a negative correlation between blood mercury concentrations and lymphocyte cell counts and aspartate aminotransferase. The positive correlation result implied that there is higher affinity of mercury species for erythrocytes than plasma. It also showed that it is important to measure hematocrit when analyzing whole blood for mercury. On the other hand, in vitro immunosuppression occurred at methylmercury concentrations that correspond to approximately 5% of the research sample which were captured in the wild. In addition, the negative correlation result found ex vivo between mercury and lymphocyte numbers and mercury and B-cell proliferative responses. This implies that there is a possibility that it is possible that mercury negatively impacts on the immune function of sea turtle in the wild.Bibliographic Information:Day, R. D., Segars, A. L., Arendt, M. D., Lee, A. M., & Peden-Adams, M. M. (2007). Relationship of Blood Mercury Levels to Health Parameters in the Loggerhead Sea Turtle. Environmental Health Perspectives 115(10), 1421+.