Accumulation of Lead and Mercury in Oncorhynchus mykiss (Salmoniformes: Salmonidae) in Peru: A Meta-analysis

Abstract

Lead (Pb) and mercury (Hg) are persistent, bioaccumulative heavy metals and are considered a risk to aquatic ecosystems and human health. In Peru, rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) is of high dietary and economic importance and can accumulate these contaminants, raising concern. The objective was to determine the accumulation of Pb and Hg in the muscle tissues of this species in Peru and to compare these concentrations with Codex Alimentarius limits. A literature search was conducted in SciELO, Google Scholar, and a Peruvian repository (Alicia). Mean concentrations of the bioaccumulated metals, standard deviations (imputed when missing), and sample sizes were extracted. A random-effects meta-analysis was performed, assessing heterogeneity (I²), publication bias (Egger and Begg tests), and subgroups by source (rivers, fish farms, lakes/lagoons). Eight studies were included. Oncorhynchus mykissshowed a mean mercury (Hg) concentration of 0.244 mg/kg (95% CI: 0.062–0.425; I² = 93%), with higher values observed in fish farms (0.394 mg/kg). For lead (Pb), the mean concentration was 0.327 mg/kg (95% CI: 0.051–0.603), with levels exceeding permissible limits in samples from rivers (0.842 mg/kg) and fish farms (0.397 mg/kg). No evidence of publication bias was found. It is concluded that Hg levels are generally below established limits, whereas Pb exceeds permissible limits in samples from rivers and fish farms; continuous monitoring and control measures are recommended to ensure food safety.