Occurrence, Spatial Distribution and Source Assessment of Organophosphate Flame Retardants in Surface Sediments of Afiesere River, Niger Delta, Nigeria

Abstract

The occurrence, spatial distribution and source assessment of six organophosphate flame retardants (OPFRs) were investigated in the sediments of the Afiesere River in the Niger Delta, Nigeria. Sediment samples were collected from twelve (12) locations along the river. Samples were subjected to ultrasound-assisted extraction using a 1:1 mixture of dichloromethane and acetonitrile. Thereafter, the extracts were analyzed for OPFRs on a gas chromatograph-mass spectrometer (GC-MS). Regression analysis was used to established if total organic carbon (TOC) influenced the geochemistry of OPFRs in the sediment. Principal component analysis (PCA) and Pearson’s correlation coefficient were used to establish the sources of OPFRs in the sediment. The concentrations of ∑6 OPFRs in surface sediments of the Afiesere River varied from 1.12 to 43.5 ng/g and were within the range of those reported in sediments from other river systems around the world. The occurrence pattern of OPFRs was in the order of TCEP > TPTP > TCPP > IDPP > TNBP > RDP. Regression analysis showed a very high correlation (R2 = 0.7273) between ∑6 OPFRs and sediments total organic carbon (TOC) indicating that TOC influenced the geochemistry and fate of OPFRs in the sediments. The Source assessment indicated that OPFRs in sediments of the Afiesere River are from mixed pollution. Further research is needed to determine the impact of the OPFRs in the Afiesere River.