Elements of concern in fillets of bighead and silver carp from the Illinois River, Illinois

• Concentrations of total As were below detection limits in most carp fillets.
• Mean Hg concentrations in fillets were below the USFDA action level.
• Mercury concentrations in some carp fillets would invoke consumption restrictions.
• Mean Se concentrations were below thresholds for consumption restrictions.
• The mean molar ratio of Se:Hg in fillets was lower in bighead than in silver carp.

Efforts to control invasive bighead (Hypophthalmichthys nobilis) and silver carp (H. molitrix) may include harvest for human consumption. We measured concentrations of arsenic (As), mercury (Hg), and selenium (Se) in fillets from silver and bighead carp collected from the lower Illinois River, Illinois, USA, to determine whether concentrations were of health concern and differed by species, size, and location. Concentrations of total As were below detection limits in most bighead (92%) and silver (77%) carp fillets, whereas inorganic As was below detection limits in all samples. Mean Hg concentrations were greater in bighead (0.068 mg kg−1) than in silver carp (0.035 mg kg−1), and were smallest in carp from the confluence of the Illinois and Mississippi rivers. Mercury concentrations in fillets were positively correlated with body mass in both species. Concentrations of Hg were below the US Food and Drug Administration’s (USFDA) action level (1 ppm as methyl-Hg); however, concentrations in some bighead (70%) and silver (12%) carp fell within the range that would invoke a recommendation to limit meals in sensitive cohorts. Mean Se concentrations were greater in silver (0.332 mg kg−1) than in bighead (0.281 mg kg−1) carp fillets, and were below the 1.5 mg kg−1 limit for an unrestricted number of meals/month. The mean molar ratio of Se:Hg in fillets was lower in bighead (14.0) than in silver (29.1) carp and was negatively correlated with mass in both species Concentrations of Hg in bighead and silver carp fillets should be considered when assessing the risks associated with the use of these species as a protein source.