US EPA

2337221 

Journal Article 

Sprinkler irrigation of rice fields reduces grain arsenic but enhances cadmium 

Moreno-Jiménez, E; Meharg, AA; Smolders, E; Manzano, R; Becerra, D; Sánchez-Llerena, J; Albarrán, Á; López-Piñero, A 

2014 

1 

Science of the Total Environment
ISSN: 0048-9697
EISSN: 1879-1026 

485-486 

468-473 

English 

24742557 

10.1016/j.scitotenv.2014.03.106 

WOS:000337259000049 

Previous studies have demonstrated that rice cultivated under flooded conditions has higher concentrations of arsenic (As) but lower cadmium (Cd) compared to rice grown in unsaturated soils. To validate such effects over long terms under Mediterranean conditions a field experiment, conducted over 7 successive years was established in SW Spain. The impact of water management on rice production and grain arsenic (As) and cadmium (Cd) was measured, and As speciation was determined to inform toxicity evaluation. Sprinkler irrigation was compared to traditional flooding. Both irrigation techniques resulted in similar grain yields (~3000kggrainha(-1)). Successive sprinkler irrigation over 7years decreased grain total As to one-sixth its initial concentration in the flooded system (0.55 to 0.09mgAskg(-1)), while one cycle of sprinkler irrigation also reduced grain total As by one-third (0.20mgkg(-1)). Grain inorganic As concentration increased up to 2 folds under flooded conditions compared to sprinkler irrigated fields while organic As was also lower in sprinkler system treatments, but to a lesser extent. This suggests that methylation is favored under water logging. However, sprinkler irrigation increased Cd transfer to grain by a factor of 10, reaching 0.05mgCdkg(-1) in 7years. Sprinkler systems in paddy fields seem particularly suited for Mediterranean climates and are able to mitigate against excessive As accumulation, but our evidence shows that an increased Cd load in rice grain may result. 

Food safety; Arsenic speciation; Water management; Cadmium; Toxicity; Rice