Chemometrics, health risk assessment and probable sources of soluble total petroleum hydrocarbons in atmospheric rainwater, Rivers State, Nigeria

Abstract

Total petroleum hydrocarbons (TPHs)—(aliphatic and aromatic) were analysed for in atmospheric rainwater between April–June; July–August; September–October depicting early, mid, late rain of 2019. Sampling at Rumuodomaya/Rumuodome and Ogale in Rivers State using basins fastened to a Table 2M above ground and 120 M from high features, Rainwater was analysed after treatment using Agilent GC-FID. Results show cumulative TPHs at R/R were 56.6551 mg/L, 39.5201 mg/L and 7.2283 mg/L, Ogale: 9.1217 mg/L, 59.4923 mg/L and 21.9825 mg/L. Aliphatic hydrocarbons: C5–C8 were < 1, low contamination, other carbon aggregates (C9–C16, C17–C35, and C36–C40) indicate high contamination. Chemometric assessment showed high contamination. TPHs aggregates at Rumuodomaya/Rumuodome were–C8–C11 (1.034 and 1.005) early rain, C18–C25 and C26–C33 has Carbon preference index of 1.287 and 1.630 (mid-rain), C26–C33 has CPI of 1.288 (late-rain), Ogale area, C26–C33 has CPI of 1.732 (early-rain), mid-rain C8–C11 (2.768) and C12–C17 (5.368). Pristane/phytane ratio indicated biogenic and pyrogenic sources. Average carbon length of TPHs for odd n-alkanes were C9–C11 (9.446) and C35–C39 (38.980), C9–C11(10.238), C35–C39 (36.510); C9–C11 (10.240) and C35–C39 (36.934). Average daily intake depicted possible health issues for children and adults as hazard index > 1 for aromatics.