Cobalt chloride cocl2.6h2o

Nanostructured tungsten carbide cobalt powder (WCCo NM) and cobalt chloride (CoCl₂.6H₂O, 98% purity, Sigma-Aldrich, St. Louis, MI, USA) were used. Materials were fully characterized as synthesized (Table 1) and also during exposure via a concurrent experiment. Spiking of the soil was done as reported in Ribeiro et al. [19 (link)]. In short, concentrations used correspond to the approximate 10% and 50% effect (reproduction) concentrations EC₁₀ and EC₅₀: 0–1200–1500 mg WCCo NMs/kg soil DW (0–100–120 mg Co/kg equivalent) and 0–110–180 mg Co/kg soil DW for CoCl₂. WCCo NMs were spiked as dry powder following OECD (Organization for Economic Cooperation and Development) guideline [32 ] recommendations for dry powder non-dispersible NMs, done per individual replicate. Moisture was 50% of the maximum water holding capacity. CoCl₂ was prepared as concentrated aqueous solution, diluted to the required concentrations, spiked onto the pre-moistened soil batches per concentration, and homogeneously mixed. The test started 1 day after spiking for both Co materials.