Phosphorus adsorption/desorption processes of estuarine sediment: a case study—Loughor Estuary, UK

Phosphorus (P) plays an important role in the eutrophication of river and marine environments. The adsorption-desorption processes of P by estuarine sediment were studied to better understand the P behaviour in the Loughor Estuary in Carmarthen Bay, UK. Three types of models were used to estimate the P adsorption isotherm for five sediment samples from the Loughor Estuary. The Langmuir adsorption isotherm showed a good fit with the linear (data) isotherm. The P desorption from bed sediment was measured as the easy exchangeable P (MgCl2 extractable). A negative correlation was found between adsorbed P in bed sediment and median particle size. A positive correlation was also found between P adsorbed and metals such as iron (Fe), aluminium (Al) and calcium (Ca) as well as the total organic carbon (TOC).