Co-exposure to Deoxynivalenol and T-2, HT-2.toxin through Cottonseed Cake: A Screening-level Risk Assessment for Livestock in Mali

Aims: To assess co-exposure to deoxynivalenol (DON) and T-2 toxin through cottonseed cake in Malian sheep and cattle, characterise potential health risks, and evaluate sensitivity to unmeasured HT-2. Study Design: Cross-sectional contamination study with deterministic and probabilistic screening-level risk assessment. Place and Duration of Study: Mali’s post-harvest cotton value chain; the sampling period was not specified. Methodology: The database included 243 determinations from triplicate analyses of 81 independent samples. Replicates were averaged, and 33 cottonseed-cake samples informed the primary assessment. Exposure scenarios comprised four observed sheep rations and cattle cake intakes of 1, 2 and 4 kg/day. Risk quotients (RQ) were calculated against species-specific reference values. Monte Carlo simulations used 100,000 iterations per scenario, preserving paired toxin concentrations. T-2-only quotients provided lower-bound estimates against combined T-2 + HT-2 reference points. Sensitivity analysis assumed HT-2 equalled T-2. Results: Mean DON and T-2 concentrations were 274.98 and 136.36 µg/kg, respectively (Spearman’s ρ = 0.912). Sheep deterministic T-2 RQ values ranged from 5.14 to 15.12; the simulated mean was 9.393 (2.5th–97.5th percentiles: 5.278–13.901), with 100% exceeding 1. Mean cattle T-2 RQ values were 0.146, 0.293 and 0.586 at 1, 2 and 4 kg/day, respectively, without simulated exceedances. Under the illustrative HT-2 = T-2 assumption, exceedance probability reached 66.5% at 4 kg/day. DON RQ values remained below 1 throughout. Conclusion: T-2 exposure indicated potential concern in sheep. Cattle estimates remained below the reference point for measured T-2 alone, but high-intake estimates were sensitive to unmeasured HT-2. Joint T-2 and HT-2 quantification in complete rations is needed before definitive safety conclusions.