Phosphorus retention in a coastal salt marsh in SE Spain

Total and inorganic soil P were extracted from a coastal salt marsh in SE Spain receiving eutrophicated water of urban and agricultural origin. The greatest P contents were obtained within the upper 10 cm of soil of those sectors of the salt marsh most affected by urban waste water effluents. Most of the P was extracted using HCl, indicating that it is mainly bonded to Ca compounds. Only in sites with low CaCO3 content was the quantity of P associated with Fe and Al oxides and hydroxides (extracted with NaOH) noticeable.