BAHTIAR DENNY EDISON. NIM. 1210247978. The Level of Contamination of Pb and Zn in the Waters of Selat Air Hitam with Snails Biomonitor of Cerithidea obtusa (Directed by Prof. Dr. Ir. Yusni Ikhwan Siregar, M.Sc and Dr. Ir. Sofyan Husein Siregar, M.Phill). A study on the pollution level of Pb and Zn by using Cerithidea obtusa as a biomonitor were conducted from October to December 2014. Ten samp…