Characterization and Source Assessment of Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments of the Fosu Lagoon, Ghana

Abstract

The first results ever obtained on polycyclic aromatic hydrocarbon (PAHs) concentrations in the Fosu lagoon surface sediments are presented together with corresponding heavy metal (Fe, Mn, Cd, Zn and Ni) concentrations. Samples collected on a monthly basis from November 2003-April 2004 (Heavy metals) and December 2003-January 2004 (PAHs) at 8 locations, representing different anthropogenic sources of contamination to the lagoon, were analyzed. Concentrations of Cd and Ni in the lagoon sediment suggest greater contamination to the lagoon from industrial activities in the vicinity of the lagoon; 50% of the sediment samples exceeded some established sediment Cd guidelines for the protection of aquatic lives. Then, 15 PAHs were detected among the sediments from the different locations and the compositional pattern in decreasing order was 3-ring > 5-ring > 4-ring > 6-ring > 2-ring PAH compounds. Sigma PAH concentrations in the sediment samples ranged from 254 to 558 mg/kg, with a mean of 359.4 mg/kg. Two distinct areas were identified to be a major source of anthropogenic load of both heavy metals and PAH; the mechanical shop in the northeastern sector of the lagoon is the main location for the input of Cd and it's associated PAH compounds (e.g., acenapthylene, acenaphthene, naphthalene and benzo[a]fluoranthene) and to a lesser extent Ni. Both combustion and petroleum sources may account for PAH loads from this area. The residential area in the northern sector is responsible for high loads of Mn and its associated PAH compounds (e.g., phenanthrene, benzo[a]pyrene and anthracene). These chemicals seem to enter the lagoon mainly by the combustion of especially wood or coal.

Assessment of dry season surface, ground, and treated water quality in the Cape Coast municipality of Ghana

“…The lagoon is only about 50 m from the Gulf of Guinea. The Lagoon is surrounded by many sites that can act as point sources for discharge of pollutants (Gilbert et al 2006). These include: domestic waste discharges from a residential area in the northern side of the lagoon, industrial waste discharge from a mechanical workshop on the North Eastern side, drains from a college and a hospital on the Western and South Western side, and household dumping and effluents and sewage from the southern end.…”

“…These may probably be outdated and may not represent current pollution trends in the municipality. We had recently published the heavy metal and PAH levels in the sediment of the Fosu Lagoon (Gilbert et al 2006), and an assessment of heavy metal pollution of one other surface water in the municipality, Iture Estuary, was only recently reported in the course of writing this manuscript (Fianko et al 2007). Recent general water quality data in water sources in the municipality are still lacking in the literature.…”

“…Due to poor or non-existing waste sewage disposal, however, most of the water sources could be heavily polluted ) and may be responsible for the outbreak of waterborne diseases such as cholera that occur during acute water shortages in the area (Amamoo-Otchere and Akuetteh 2005; Accra Mail 2002). It is also possible for the contaminants in these waters to also include trace toxic metals and other potentially harmful chemicals such as Hg (Ntow and Khwaja 1989), Cd, Se, Pb (Fianko et al 2007), and polycyclic aromatic hydrocarbons (PAHs; Gilbert et al 2006), which based on their concentration in the raw water, the nature of the raw water, and the control measures in place may not be thoroughly removed by the treatment process already installed to attain required drinking water quality standards (WHO 2004).…”

Levels, Distribution and Sources of Polycyclic Aromatic Hydrocarbons in Surface Water in the Lower Reach of Qua Iboe River Estuary, Nigeria

“…The result for correlation analysis between individual PAHs in water from QIRE revealed that the in Surface Water in Lower Reach of Qua Iboe River Estuary, Nigeria compounds were derived from a common anthropogenic origin [27]. The strong positive correlation between B(k)F and chrysene observed in this study may be due to close relatedness in molecular weight [28].…”

Characterization of macro-benthic fauna for ecological health status of the Fosu and Benya lagoons in coastal Ghana

“…The Fosu Lagoon is considered to be highly polluted (Armah et al 2010) due to the disposal of waste, water withdrawal for irrigation, reduction in size of the popular black chin tilapia in recent years, and increasing severity of algal blooms (Gilbert et al 2006, Darkwa andSmardon 2010). Discharge into the lagoon from a cluster of mechanical workshops a source of Iron (Fe), Magnesium (Mn), Cadmium (Cd), Zinc (Zn), and Nickel (Ni) in the Fosu Lagoon (Gilbert et al 2006). Though there is no industrialization around the Benya Lagoon, its proximity to a fish market, which serves about 500 individuals weekly, creates the likelihood of waste and effluent disposal through the associated anthropogenic activity.…”