Petroleum Hydrocarbon Fingerprints of Water and Sediment Samples of Buffalo River Estuary in the Eastern Cape Province, South Africa

Abstract

Petroleum hydrocarbon status of the Buffalo River Estuary in East London, South Africa, was evaluated from January to May, 2016. Surface water and sediment samples were collected from five points in the estuary and extracted using standard methods. The extracts were subsequently analyzed by gas chromatography-flame ionization detection. Results showed that total petroleum hydrocarbon (TPH) varied from 7.65 to 477 μg/L in the water and 12.59 to 1,100 mg/kg in the sediments, with mean values of 146.50 ± 27.96 μg/L and 209.81 ± 63.82 mg/kg, respectively. Concentrations of TPH in the sediments correlated significantly with organic carbon (OC) in both seasons. TPH and OC levels were slightly lower in summer than in autumn in the two environmental matrices, and the average amount of TPH in the water samples collected from all the sampling stations was generally lower than the EU standard limit of 300 μg/L. However, the levels in the sediments exceeded the EGASPIN target value (50 mg/kg) for mineral oil but were below the intervention value (5,000 mg/kg), indicating a serious impact of industrial growth and urbanization on the area, although the n-alkane ratios and indexes used for source tracking revealed excessive flow from both natural and anthropogenic sources.

Levels of Polycyclic Aromatic Hydrocarbons in the Water and Sediment of Buffalo River Estuary, South Africa and Their Health Risk Assessment

“…The levels at E1 may be attributed to pollution load along the course of the river from major towns, such as Zwelisha, King Williams Town, and Mdantsane, whereas the pollution at E4 may be related to probable leakage of petroleum products from two-stroke engines of the fishing boats, which are usually parked at the Fish Market in the area, stormwater from East London harbour, vehicular emissions from Steve Biko Bridge, and nonpoint source pollution that enters the waterbody as runoff and sewerage through the first creek (RHP 2004 ; EOHCES 2016 ). Similarly, PAHs’ contamination of water at E3 cannot be unconnected with the discharge of industrial wastewater and accumulation of leachates at the creek possibly from an old solid waste landfill site, wastewater treatment facilities, and Wilsonia industrial and residential areas (Adeniji et al 2017 ). Concentrations of the organic contaminants in all the sampling points were higher than the target value of 30 μg/L for PAHs in the marine waters (Fig.…”

“…The peak areas calculated using the baseline–baseline mode with Agilent Chemstation software were used to plot calibration curves for all the 16 PAH congeners (Ma et al 2010 ; Nekhavhambe et al 2014 ). The curves were all linear with correlation coefficients falling within the acceptable range of r 2 ≥ 0.990 (Adeniji et al 2017 ). Samples were thereafter identified by their retention times, whereas quantification was done by the instrument on the basis of the response factor generated for each congener from the linear curve plotted (Ma et al 2010 ; Nekhavhambe et al 2014 ).…”

“…A detailed description of the study area presented in Table 1 and Fig. 1 is available in the previous report by Adeniji et al ( 2017 ).…”

“…Those findings revealed gross pollution of both environmental matrices. Recently, fairly high concentrations of total petroleum hydrocarbons, organochlorine pesticides, polychlorinated biphenyls, and some phenolic derivatives also were documented in the zone (Adeniji et al 2017 ; Yahaya et al 2017 , 2018 , 2019 ). However, no report is available till date on the status of the polycyclic aromatic hydrocarbons (PAHs) in the area; hence, it became very expedient to investigate, giving its proximity to the river port and some notable industries around.…”

Aliphatic Hydrocarbons in Recent Dated Sediment Cores of Imo River, SE Nigeria: Environmental/Historical Implications

“…6 a, b, c). For instance, higher levels of TAH were recorded in sediments from Khniss Tunisian coast, Mediterrenean sea (1020 -2332 µg/g dw, Zrafi et al 2013); Buffalo river estuary, South Africa (12.59 -1100 µg/kg dw, Adeniji et al 2017); Tropical Brazilian estuarine system (27.8 -139.5 µg/g dw, Thias et al 2013); Lake Washinton, USA (11 -900 µg/g dw, Stuart et al 2004).…”