Insights into potential health risk of heavy metals from farmed fish and fish feed in renowned fish-growing region of Bangladesh

Toxic elements can be accumulated into human body through fish chain as fish is exposed to metals through water, sediment and contaminated feeds. Therefore, the study was conducted to determine the heavy metal content of fish species and their feeds, as well as the potential health risks associated with them. Forty-five fish samples were collected from fifteen fish farms whereas thirty feed samples were collected from three upalizas of Mymensingh district during June to August 2022. The collected samples were digested with an acid mixture, and concentrations of twelve heavy metals were measured by ICP-MS. Fe predominates over the other metals in almost all samples. All three fish species contained the higher concentration of Fe, Ni, Zn and Cr. The concentrations of Fe, Ni, Zn and Cr are 20.84, 9.4, 6.60, 1.86 mgkg -1 for Pangasius, 25.8, 13.82, 8.91 and 2.00 mgkg -1 for Rui and 27.58, 7.08, 7.92 and 2.09 mgkg -1 for Tilapia, respectively. The WHO/EU standard limits for Cr, Mn, Ni, and Pb were exceeded in feed samples from farmers and in commercial feeds. Tilapia fish species had a strong propensity to acquire As, Co, and Ni from farmer-supplied feeds and As and Se from commercial feeds as BFAF value was higher than 1. The degree of contamination across all species can be characterized as follows: Tilapia > Rui > Pangasius. The mean estimated daily intake of the heavy metals was lower than the recommended daily allowance. Except for Fe, the THQ values for fish species were less than 1. Conversely, HI in all species was higher than the allowable threshold of 1. Carcinogenic risks from Ni and Pb consumption were present in all fish species. Antibiotics, especially oxytetracycline and tetracycline, were detected in various fish samples. The results suggest that the authority should take appropriate precautions to ensure feed quality and prevent significant heavy metal exposure from farmed fish.