Assessment of trace metals in fish species of urban rivers in Bangladesh and health implications

•Metals were varied between season and fish species.•Cu, As and Pb in water samples exceeded the toxicity reference value.•Metals were mostly contributed by anthropogenic activities.•As indicated considerable risk to the local inhabitants.

Levels of six metals i.e. chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), cadmium (Cd) and lead (Pb) in three fish species (Channa punctatus, Heteropneustes fossilis and Trichogaster fasciata) from three urban rivers in Bangladesh were measured. Concentrations of Cr, Ni, Cu, As, Cd and Pb in fish species were 0.75–4.8, 0.14–3.1, 1.1–7.2, 0.091–0.53, 0.007–0.13, and 0.052–2.7 mg/kg ww, respectively. The analyzed metals were significantly different between species and seasons (p < 0.05). The target hazard quotients (THQs) and carcinogenic risk (CR) for individual metal showed that As and Pb in muscle was particularly hazardous and potential risk for the low, medium and high fish consumer in Bangladesh. Some of the trace metals’ concentrations are higher than the recommended value, which suggest that the water and fish of these rivers are not completely safe for human health.