Evaluation of potential effects of soil available phosphorus on soil arsenic availability and paddy rice inorganic arsenic content

The transfer of arsenic from paddy field to rice is a major exposure route of the highly toxic element to humans. The aim of our study is to explore the effects of soil available phosphorus on As uptake by rice, and identify the effects of soil properties on arsenic transfer from soil to rice under actual field conditions. 56 pairs of topsoil and rice samples were collected. The relevant parameters in soil and the inorganic arsenic in rice grains were analyzed, and then all the results were treated by statistical methods. Results show that the main factors influencing the uptake by rice grain include soil pH and available phosphorus. The eventual impact of phosphorus is identified as the suppression of As uptake by rice grains. The competition for transporters from soil to roots between arsenic and phosphorus in rhizosphere soil has been a dominant feature. [Display omitted] •At low soil As levels As fractions play a decisive role in soil As availability.•Competition between As and P uptake is enhanced at high soil As levels.•Soil P availability is restricted by low pH. Under the condition of sufficient arsenic in soil, available phosphorus plays a decisive role in inorganic arsenic uptake by paddy rice.