Trace elements contamination in the aquatic ecosystem is a current and major environmental concern due to their non-degradable nature and toxic effects on human health. Concentrations of arsenic (As), chromium (Cr), cadmium (Cd) and lead (Pb) in fish were estimated to evaluate contamination levels and health risks for Bangladeshi adults. A total of six demersal fish species namely Mystus vittatus, Polynemus paradiseus, Sillaginopsis panijus, Lates calcarifer, Cynoglossus arel and Pseudapocryptes elongates were collected in summer and winter season from the coastal Karnaphuli River, Bangladesh. The analyzed trace elements varied between different species of fish. The concentration of studied trace elements exceed Food and Agriculture Organization/World Health Organization maximum tolerable intake indicating risk to human body. The mean concentration of As, Cr, Cd and Pb were found 2.18, 9.1, 7.2 and 4.38 times higher than the recommended value. Health risks associated with these trace element intakes were evaluated in terms of dietary intake and target hazard quotients (THQs). The THQs value for individual fish species was more than one which was responsible for non-carcinogenic health hazard due to fish consumption. Target Carcinogenic Risk (TR) value for arsenic and lead was also higher than USEPA standard (10−4) indicated chronic cancer risk to human. From the health point of view, this study showed that the inhabitants who consume these fishes are exposed chronically to trace elements pollution with carcinogenic and non-carcinogenic consequences.