Applying the monitoring breakdown structure model to trace metal content in edible biomonitors: An eight-year survey in the Beagle Channel (southern Patagonia)

[Display omitted] •6 metals determined in two edible biomonitors/mollusks (2005 → 2012) Beagle Channel.•MBS → Enhancing information variety → 729 samples/13000 determinations/.•For Cd and Pb, 65%−40% bivalves exceeded max levels of Mercosur.•Mytilus: Cr, Cu, Ni, Pb, Zn → safe for consumption/ EDIs lower → safety refs. doses.•Nacella: → less safe species (high consumers) due to high Cd levels → THQ and H I > 1. The purpose of this paper is to investigate the trace metal content in edible biomonitors (i.e., mollusks) in the Beagle Channel (southern Patagonia) and to assess the human health risks associated with their consumption. Rationale: The monitoring breakdown structure (MBS) conceptual model was applied to four sampling campaigns (2005 → 2012) that collected 729 samples of Mytilus chilensis and Nacella magellanica. The composition of trace elements (Cd, Cr, Cu, Ni, Pb and Zn) in the mollusks was determined using graphite furnace (GFAAS) or flame atomic absorption spectrometry (FAAS). We compared the mean obtained values with the maximum levels (MLs) of each element established by international organizations. Then, based on semi-structured interviews, we calculated the estimated daily intake (EDI) of local residents and compared it with safety reference doses, i.e., the provisional tolerable daily intake (PTDI), provisional maximum tolerable daily intake (PMTDI), and tolerable daily intake (TDI), as well as the benchmark dose level lower confidence limit for Pb (BMDL01, a reference point (RP)/point of departure (POD). Moreover, to obtain information about the potential health risks of ingesting heavy metals (HMs) through mollusk consumption, we evaluated the target hazard quotient (THQ) and the hazard index (HI). Findings: For Cd and Pb, 65% and 40% of bivalves exceeded the MLs established by the Mercado Común del Sur (Mercosur), respectively. Except for Cd in N. magellanica (i.e., 1.20 μg/kg/bw/day), EDI values were clearly lower than the safety reference doses. For Cr, Cu, Ni, Pb and Zn, mussels were safe for consumption and did not raise concerns for public health. Likewise, THQ values were well below one for most of the studied metals, indicating that the exposed human population is assumed to be safe. Occasional high consumers of mollusks from the most contaminated sites may be at some health risk. Originality: The food production system and the environment are complex systems; this is crucial to understand when we consider ecosystems as a food sou