A kinetic study on accumulation and depuration of hexavalent chromium in crucian carp (Carassius auratus) reveals the potential health risk of fish head consumption

Abstract

In this study, crucian carp ( Carassius auratus ) was exposed to graded levels of waterborne Cr 6+ (0, 0.1, 1 and 10 mg/L) for 28 days and subsequently transferred to clean water for 20 days. Fish tissues were collected every 4 days. The Cr 6+ levels in tissues were determined and the potential health risks from consuming fish muscle and fish head were assessed. The results indicated that the Cr 6+ contents in the head were always higher than those in muscle and that 10 mg/L Cr 6+ treatment conferred risk in fish head consumption throughout the entire experimental period. A further kinetic study on the accumulation and depuration of Cr 6+ in tissues indicated that compared to muscle, the higher Cr 6+ content in fish head was attributed to the greater uptake rate (k 1 ) and kinetic bioconcentration factor (BCF k ), although the k 1 and BCF k values in the muscle and head were lower than those in the liver, kidney, intestines and gills. The maximum Cr 6+ concentrations in tissues at theoretical equilibrium (C max ) ranged from 0.55 mg/kg in muscle to 112 mg/kg in intestines with exposure to 10 mg/L Cr 6+ . Moreover, the results of the distributions and transitions of Cr 6+ in fish tissues demonstrated that fish head and muscle were short-term storage organs while the kidney was a long-term storage organ for Cr 6+ . Overall, compare to muscle, fish head has a higher capacity for Cr 6+ accumulation, which poses a higher potential health risk to humans, especially to children, once the fish is contaminated by Cr 6+ . • The kinetics of Cr 6+ in fish tissues were studied using a two-compartment model. • Fish head has a higher uptake rate for Cr 6+ than that in fish muscle. • The relative burdens of Cr 6+ in fish tissues were firstly reported. • Fish head and muscle could be short-term storage organs of Cr 6+ . • Kidney could be a long-term storage organ of Cr 6+ .