Occupational dosimetric assessment (inhalation pathway) from the application of phosphogypsum in agriculture in South West Spain

Phosphogypsum (PG) has been traditionally applied as Ca-amendment in saline marsh soils in SW Spain, where available PG has 710 +/- 40 Bq kg(-1) of Ra-226. This work assesses the potential radiological risk for farmers through Rn-222 exhalation from PG-amended soils and by inhalation of PG-dust during its application. A three-year field experiment was conducted in a commercial farm involving two treatments: control and 25 t PG ha(-1) with three replicates (each 0.5 ha plots). The Rn-222 exhalation rate was positively correlated with potential evapotranspiration, which explained 67% of the variability. Statistically significant differences between the control and PG treatments were not found for Rn-222 exhalation rates, and mean values were within the lowest quartile of the typical range for Rn-222 exhalation from soils. Airborne dust samples were collected during the application of PG and sugar-beet sludge amendments. The highest PG-attributable Ra-226 concentration in the dust samples was 3.3 x 10(2) mu Bq m(-3), implying negligible dose increment for exposed workers. (c) 2009 Elsevier Ltd. All rights reserved.