Larvae of Tenebrio molitor L. (Coleoptera: Tenebrionidae) are particularly suitable as novel food for the human consumption; nevertheless, there are some potential safety risks linked with insect consumption. In this study we investigated the presence of Cd, Pb, Ni, As, Hg in new feeding substrates coming from solid residues generated by olive fruits processing, called olive-pomace, and their influence on the metal content in larvae of T. molitor. Morover, bioaccumulation factor and the mercury-selenium balance were evaluated. Analyses were carried out via graphite furnace atomic absorption spectrophotometry for Cd, Pb, Ni, As and Se, and via Direct Mercury Analyzer for Hg. All metal concentrations found in feeding substrates were below the legal limit of undesirable substances in animal feed (2002/32/EC). Concentrations in larvae were in the range (mg kg⁻¹ wet weight): Cd 0.008–0.016, Pb 0.063–0.079, Ni 0.03–0.63, As 0.021–0.023, Hg 0.12 × 10⁻³–0.49 × 10⁻³, and Se 0.057–0.085. Statistically significant correlation between metal content in feeding substrates and in larvae was evidenced only for Hg, which bioaccumulates. Se protects from mercury toxicity, with a Selenium Health Benefit Value (HVB_Se) of > 0. Overall, our results indicate that the risk of exposure to metals from consumption of mealworm larvae is relatively low and in compliance with European Union regulations.

Mercury (Hg) is a well-known toxic element, diffused in the environment, especially in the Mediterranean Sea which is rich in cinnabar deposits. Mercury bioaccumulation in fish is of great concern, especially for top-level aquatic predators (e.g., shark, tuna, swordfish) and above all for species of large human consumption and high nutritional value. This work aimed to determine Hg concentrations in farmed and wild Atlantic Bluefin tuna (Thunnus thynnus) caught in the Mediterranean area in order to evaluate the level of Hg bioaccumulation. selenium (Se) content was also determined, since this element is an antagonist of mercury toxicity. Mercury and Se were analysed by atomic absorption spectrometry after microwave digestion of the samples. Hg content in farmed tuna was below the legal limit (1 mg/kg, wet weight, w.w.) for all specimens (0.6 ± 0.2 mg/kg), whereas the wild ones had a content over the limit (1.7 ± 0.6 mg/kg); Se concentration was higher in farmed specimens (1.1 ± 0.9 mg/kg) compared to wild ones (0.6 ± 0.3 mg/kg). A safe seafood could show a Se/Hg ratio >1 and a health benefit value (HBV_Se) > 0: farmed tuna had higher values than the wild specimens (Se/Hg 5.48 vs. 1.32; HBV_Se 11.16 vs. 0.29). These results demonstrate that for Hg, there is a better risk/benefit ratio in farmed T. thynnus. making it safer than wild tuna.

Size-fractionated particulate mercury (PHg) measurements were performed from November 2017 to January 2018 at Terra Nova Bay (Antarctica) for the first time. Samples were collected every 10 days by a six-stage high-volume cascade impactor with size classes between 10 μm and 0.49 μm. Total PHg concentrations were maxima (87 ± 8 pg m⁻³) in November, then decreased to values ~40% lower and remained almost constant until the end of the sampling period (~30 pg m⁻³). The trimodal aerosol mass distribution reveals that from 30% to 90% of the total PHg came in the size > 1.0 μm. Hg in the two coarse fractions was probably produced by the adsorption of oxidized Hg species transported by air masses from the Antarctic plateau or produced locally by sea ice edges. PHg in accumulation mode seemed to be related to gas–particle partitioning with sea salt aerosol. Finally, average dry deposition fluxes of PHg were calculated to be 0.36 ± 0.21 ng m⁻² d⁻¹ in the accumulation mode, 47 ± 44 ng m⁻² d⁻¹ in the first coarse mode, and 37 ± 31 ng m⁻² d⁻¹ in the second coarse mode. The present work contributed to the comprehension of the Hg biogeochemical cycle, but further research studies are needed.