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

Abstract

The incidence and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in the Buffalo River Estuary in the Eastern Cape Province of South Africa were assessed in this study. A total of 60 surface water and 19 sediment samples were collected from 5 sites of the estuary over a period of 6 months (December 2015 to May 2016). Extraction of PAHs from the water and sediment samples was achieved by using liquid–liquid and soxhlet extraction methods respectively, followed by column clean up with silica gel and quantification by gas chromatography–flame ionization detection. Individual PAH levels in the water and sediment samples ranged from not detected (ND) to 24.91 μg/L and ND to 7792 μg/kg, respectively. Total concentrations of the PAHs in the water and sediment samples varied as 14.91–206 μg/L and 1107–22,310 μg/kg in that order. Total levels of the contaminants were above the target values in the two matrices and were higher in summer than autumn. Although the noncarcinogenic risk of PAHs estimated in the water column through dermal absorption was very low compared with the target value, the carcinogenic risk determined was high for both adults and children. Similarly, benzo(a)pyrene and dibenzo(a,h)anthracene were found to be of higher carcinogenic and mutagenic risks in the sediments collected from the study area. Diagnostic ratios suggest that the target hydrocarbons are predominantly from pyrolytic sources. It therefore could be inferred that the water body is conspicuously polluted; hence, efforts should be made to control all the activities contributing to such magnitude of pollution at the sites.

Polycyclic Aromatic Hydrocarbons: Sources, Toxicity, and Remediation Approaches

“…Due to their inherent properties, PAHs are persistent pollutants having a wide range of biological toxicity; remediation of PAHs from the environment has been a global concern. The PAH pollutants are ubiquitous, found equally in aquatic and terrestrial ecosystems as well as in the atmosphere (Adeniji et al, 2019). The rate of deposition of PAHs was found to accelerate in the soil/sediments due to their higher hydrophobicity and low aqueous solubility.…”

Estimation of Polycyclic Aromatic Hydrocarbons Pollution in Mediterranean Sea from Volturno River, Southern Italy: Distribution, Risk Assessment and Loads

“…Moreover, the carcinogenic 5–6-ring PAHs were present in low concentrations, accounting for only 17% of the total PAHs. The amount of ΣPAHs in the DP samples (64.3–1429.1 ng L −1 ) was much higher than those found in other rivers of the world ( Table 2 ) as in the Xijiang River [ 43 ], in the Yellow River [ 44 ], in the Songhua River, China [ 45 ], in the Wyre River, England [ 46 ], in the Elbe and Weser Rivers, Germany [ 47 ], and in the Tiber River, Italy [ 34 , 48 ].However, the PAHs were present in smaller quantities than those found in the Daliao River [ 49 ], in the Yellow River [ 50 ], in the Songhua River [ 51 ], in the Daliao River estuary, China [ 52 ], in the Gomti River, India [ 53 ], in the Cauca River, Colombia [ 8 ], in the Almendares River, Cuba [ 54 ], and in the Buffalo River estuary, South Africa [ 55 ]. The PAHs concentrations found inthis study are similar to those seen in the Henan Reach of Yellow River, China [ 56 ], in the Danube River, Hungary [ 57 ], and in the Sarno River [ 26 ].…”

“…The comparison showed that the amount of ΣPAHs in the sediment samples (434.8–872.1 ng g −1 ) was similar to those found in the Yellow River, China [ 50 ], in the Erjien River, Taiwan [ 60 ], and was greater than the concentration found in the East China Sea, China [ 61 ], in the Yellow River and in the Henan Reach of Yellow River, China [ 44 , 56 ], in the Yellow River Estuary, China [ 62 ], in the Danube River, Hungary [ 57 ],and in Italy, in the Tiber River [ 34 , 48 , 63 ] and in the Sarno River [ 26 ]. However, the amount of ΣPAHs in the sediment samples was lower than the concentration found in the Daliao River, China [ 49 ], in the Cocó and Ceará Rivers, Brazil [ 64 ], in the Cauca River, Colombia [ 8 ], in the Buffalo River Estuary, South Africa [ 55 ], in the Ammer River, Germany [ 9 ], and in Durance River and Huveaune River, France [ 65 , 66 ]. Low PAHs concentrations can be justified by the low total organic carbon (TOC) (1.1–9.5 mg g −1 , mean value of 5.1 mg g −1 ) and high content of sand; the association between %TOC and the ΣPAHs is shown in Figure 2 .…”

Estimation of Polycyclic Aromatic Hydrocarbons pollution, risk assessment and loads into Mediterranean Sea from Volturno River, Southern Italy.

“…The prevalence of low molecular weight PAHs (2-3-ring) in the water could be explained by their high water solubility and relatively high vapor pressures [36,37,38]. Compared with the water of polluted rivers in other parts of the world (Table 2), the concentration of ΣPAHs in the the Volturno River dissolved phase (64.3-1429.1 ng L − 1 ) was much higher than those found in the Xijiang River, China by Deng et al [39], in the Yellow River (China) by Li et al [40], in the Songhua River (China) by Ma et al [41], in the Wyre River, England by Moeckel et al [42], in the Elbe and Weser Rivers, Germany by Siemers et al [43], in the Marseilles coastal area, France by Guigue et al [44] and in the Tiber River (Italy) by Patrolecco et al [45] and Montuori et al [22]; these levels were however lower than those found in the Daliao River, China by et al [46], in the Yellow River (China) by Zhao et al [47], in the Songhua River (China) by Zhao et al [48], in the Daliao River estuary (China) by Zheng et al [49], in the Gomti River, India by Malik et al [50], in the Cauca River, Colombia by Sarria-Villa et al [8], in the Almendares River, Cuba by Santana et al [51] and in the Buffalo River estuary, South Africa by Adeniji et al [52]. Based on these results, the levels of PAHs in the dissolved phase in the Volturno River are comparable to those found in the Henan Reach of Yellow River, China by Sun et al [53], in the Gulf of Tunis, Tunisia by Mzoughi and Chouba [54], in the Danube River, Hungary by Nagy et al [55] and in the Sarno River by Montuori and Triassi [22].…”

“…In comparison with polluted rivers in other parts of the world ( [30], and in the Sarno River by Montuori and Triassi [22]. The concentration of ΣPAHs in the samples of sediment from the Volturno River and river mouth was inferior than the concentration found in the Daliao River, China by Guo et al [46], in the Caspian sea coast, India by Yancheshmeh et al [68], in the Ba n Bay, Canada by Foster et al [69], in the Cocó and Ceará Rivers, Brazil by Cavalcante et al [70], in the Bahia Blanca Estuary, Argentina by Oliva et al [10], in the Cauca River, Colombia by Sarria-Villa et al [8], in the Buffalo River Estuary, South Africa by Adeniji et al [52], in the Ammer River, Germany by Liu et al [9], in the Portimão Harbor, Portugal by Bebianno et al…”