Overview
This rearing experiment fed yellow mealworm and black soldier fly larvae on feed spiked with cadmium, lead or arsenic at half, one and two times the EU maximum level for complete feed, plus two controls. Black soldier fly larvae accumulated cadmium (bioaccumulation factor above 1 in every treatment, including controls), while mealworms accumulated arsenic and largely excreted lead and cadmium.
Key numbers
- Spiking levels at 1.0 ML: arsenic 2.00, cadmium 0.50, lead 5.00 mg/kg feed (Table 1).
- Black soldier fly cadmium bioaccumulation factor 5.8 to 9.5 across treatments; mealworm arsenic factor 1.4 / 1.6 / 2.6 at 0.5 / 1.0 / 2.0 ML (Table 3).
- Two days on clean feed lowered cadmium in black soldier fly larvae by 30% (Results text).
Methods (brief)
Feed and freeze-dried larvae were digested with nitric acid in a microwave and analyzed by graphite-furnace atomic absorption spectrometry (detection limit 0.1 mg/kg). Bioaccumulation factors were computed on a dry-matter basis as larval concentration divided by feed concentration.
Evidence Fitness
An experimental uptake study with deliberately contaminated feed, not a survey of insects sold as food. Larval concentrations appear only in bar charts (Fig 1) and an unfiled supplement, so no occurrence values were extracted; the bioaccumulation factors and the clean-feed purge result are useful for rearing-control evidence on the edible insects page.