Accumulation Characteristic of Flax on Cadmium and Arsenic in Calcareous Soil : Exploring the Safe Utilization Strategy of Wastewater-Irrigated Land

Flax (Linum usitatissimum L.) is wildly cultivated in temperate climates due to its economic value of fibers and nutritional value of seed. Here, the accumulation characteristics of flax on Cd and As and environmental risks of flax grown in wastewater-irrigated agricultural soil were studied. The concentrations of Cd and As in the studied soil were 3.62-184.72 and 0.34-2.36 times of the Chinese soil environmental quality standards, respectively. The concentrations of Cd and As were mainly accumulated in root and stalk, while the lowest concentration of Cd in husk and that of As in seed. Only 3.87-10.55% of Cd and 17.21-30.48% of As in seed migrated into oil, which was much lower than those in pomace. Interestingly, the concentrations of Cd and As in seed all exceeded the maximum levels (MLs) (Cd:0.5 mg kg-1; As:0.1 mg kg-1) recommended by the Codex Alimentarius Commission by 1.80-18.22 and 1.10-3.05 times, whereas those in oil all lower than the corresponding MLs. The hazard quotient indicated that the non-carcinogenic risks of oil intake by adults and children were negligible, while that of seed can't be negligible. Our results suggest that oil produced by flax seed can safely consume when flax was grown in wastewater-irrigated agricultural land