Overview
The authors reared yellow mealworm larvae for about four months on five diets made from organic wheat products and olive pomace, then measured cadmium, lead, nickel, arsenic, mercury and selenium in the substrates, larvae and frass. Only mercury showed a significant link between substrate and larval levels. Nickel and mercury rose as the share of olive pomace rose. Lead in larvae was far higher than in the feed, which the authors think came from the carrots given for moisture.
Key numbers
- Wet weight, across the five diets: cadmium 0.008 to 0.016, lead 0.063 to 0.079, arsenic 0.021 to 0.023 mg/kg (Table 3).
- Nickel 0.030 mg/kg on wheat flour versus 0.63 mg/kg on the 75% olive pomace diet; mercury 0.12 × 10^-3 to 0.49 × 10^-3 mg/kg (Table 3).
- Lead bioaccumulation factor 34 on wheat flour and 5.2 to 12 on the other diets, dry weight (Table 2).
Methods (brief)
Microwave acid digestion and graphite-furnace AAS for cadmium, lead, nickel, arsenic and selenium, and a direct mercury analyzer for mercury, all in a clean-room laboratory. The DORM-2 reference material agreed within 11% of certified values.
Evidence Fitness
High-quality chemistry, but this is a controlled rearing experiment, not a survey of mealworms sold as food. It shows how substrate choice moves nickel and mercury in farmed larvae. The per-diet dry-weight values appear only in figures; the wet-weight table is the citable source.