Natural radioactivity in groundwaters around a fertilizer factory complex in South of Spain

Abstract

A study ofthe concentration ofthe U isotopes, 226Ra and 230Th in a groundwater system has been carried out. This aquifer, located in the provinces of Sevilla and Huelva, is the most important in the south of Spain having a surface area of2500 km2 . The proximity of a fertilizer factory complex to this aquifer system is of particular concern given that it releases a significant part ofits waste directly into the estuary ofthe Odiel and Tinto rivers, also storing a further part on the right bank ofthe Tinto river. Investigation has been made ofthe environmental impact ofthe fertilizer factory, either as a result ofleaching ofradionuclides from the phosphogypsum piles or otherwise as a result ofintrusion ofthe Odiel and Tinto waters, both ofwhich are in close contact with the aquifer. Results show U concentration in waters of this system around the phosphogypsum piles to be significantly higher than those in other areas ofthe same aquifer. The low 226Ra concentrations found in the same locations add support to the origin of part of the U in these samples.