Concentrations, spatial and seasonal variations of Organophosphate esters in UK freshwater Sediment

This study provides the first report of organophosphate esters (OPEs) in UK freshwater sediments with a focus on the possible impact of factors such as spatial/seasonal variation and wastewater treatment plants (WWTPs) on the measured OPE concentrations in surficial sediment from 3 UK rivers and 1 canal. Detection frequencies of: (tris (chloroethyl) phosphate (TCEP), tris (2-chloroisopropyl) phosphate (TClPP), tris (1,3-dichloro-2 propyl) phosphate (TDClPP), tri-n-butyl phosphate (TNBP), tris (2-butoxyethyl) phosphate (TBOEP), 2-ethylhexyl diphenyl phosphate (EHDPP), tris (phenyl) phosphate (TPHP), and tri-m-tolyl phosphate (TmTP)) ranged from 58% to 100%. The concentration of Σ₈OPEs ranged from 107 ng g⁻¹ (dry weight - dw) (in the Worcester-Birmingham canal) to 52 ng g⁻¹ (dw) in both Rivers Severn and Sowe). The highest ∑₈OPE concentration for all study locations was recorded during the autumn months (September, October, and November), and concentrations of ∑₈OPEs in sediment samples from the River Severn, River Tame, and River Sowe all varied inversely with the river level and flow rate. The average concentrations of each target OPE in each study location were lower than those reported elsewhere but fell broadly within the range of concentrations reported from other countries. The potential risk posed by target OPEs in all study locations was found to be low, except for a moderate risk identified for EHDPP in the Worcester - Birmingham canal.