Distribution pattern and health risk assessment of polycyclic aromatic hydrocarbons in the water and sediment of Algoa Bay, South Africa

Abstract

Polycyclic aromatic hydrocarbons are amongst the pollutants of major concern in the terrestrial and aquatic habitats. They are mostly characterised by carcinogenic and non-carcinogenic effects. Distribution and potential health risks of sixteen priority PAHs in the water and sediment samples collected between December 2015 and June 2016 from Algoa Bay, South Africa, were evaluated. Water and sediment samples collected were extracted with liquid–liquid and soxhlet extraction methods, respectively, and then cleaned up using glass column loaded with silica gel. Final concentrations of the target PAHs were determined by gas chromatography interfaced with flame ionization detector. Results indicated that individual PAH concentrations in surface water, bottom water and sediment samples ranged from not detected (ND) to 24.66 µg/L, ND to 22.81 µg/L and ND to 5.23 mg/kg correspondingly. Total PAHs concentrations varied as 12.78–78.94 µg/L, 1.20–90.51 µg/L and 1.17–10.47 mg/kg in the three environmental matrices in that order. The non-carcinogenic risk was generally below 1, whereas risk indices (dermal contact) were above the acceptable limit of 1 × 10 −4 in the water column, suggesting possible carcinogenic effects to humans, with adults being the most vulnerable. Similarly, highest contributions to TEQs and MEQs in the sediments were made by benzo(a)pyrene and dibenzo(a,h)anthracene, the two most toxic congeners, signifying the possibility of carcinogenicity and mutagenicity in humans. Diagnostic ratios of PAHs reflect a prevailing pyrogenic input all through. The pollution was albeit moderate, yet regular check is recommended to ensure safe and healthy environment for human and aquatic lives. Electronic supplementary material The online version of this article (10.1007/s10653-018-0213-x) contains supplementary material, which is available to authorized users.

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

“…They were found within the intermediate range of ERL–ERM, suggesting occasional adverse biological effects to the aquatic animals. Concentrations above ERM value is an indication of adverse effects on the ecosystem and likely danger to human health as well (Jiao et al 2012 ; Tornero and d’Alcalà 2014 ; Adeniji et al 2018a , b ). The concentrations recorded in this study therefore imply that the estuary is fairly polluted with PAHs.…”

“… Phen phenanthrene, Anth anthracene, Chry chrysene, BaA benzo[a]anthracene, Flt fluoranthene, Pyr pyrene, InPy indeno(123,cd)pyrene, BghiP benzo[g,h,i]perylene, LMW low molecular weight, HMW high molecular weight (Moyo et al 2013 ; Adeniji et al 2018a , b ) …”

“…Sediment samples were air-dried in the dark for approximately 5 days and then were crushed and sieved with 0.5-mm mesh. Approximately 10 g of the sieved sediment sample was mixed with sufficient amount of anhydrous sodium sulphate, spiked with 1 mL of the surrogate standard mixture, and extracted in a Soxhlet extractor with 200 mL of dichloromethane for 24 h. The extract was filtered through anhydrous sodium sulphate into a clean amber glass bottle, concentrated using rotary evaporator and solvent exchanged into n-hexane (WSDE 1997 ; Kafilzadeh et al 2011 ; Adeniji et al 2018b ).…”

“…They associate freely with dissolved organic matter in the natural water through several means of binding and adsorption, especially those with high molecular weights (Akkanen et al 2005 ; Zheng et al 2007 ; Smith et al 2011 ; Yu et al 2011 ; Lin et al 2018 ) and are subsequently deposited in the sediment, thus accumulating to a higher level of toxicity in the aquatic environment (Prabhukumar and Pagilla 2010 ; Brazkova and Krastanov 2013 ; Olatunji et al 2014 ). The bioavailability of PAHs to the aquatic animals and also their penetration of dietary sources has thus become unavoidable (Sakuma et al 2011 ; Adeniji et al 2018b ).…”

Natrium Karbonat : Termodinamika dan Transport Ion

“…Natrium karbonat biasanya terjadi secara alami di daerah (236) kering terutama endapan material (batuan evaporit) yang akan terbentuk ketika danau musiman mengalami penguapan. Endapan (92)(93)(94)(95)…”