Health risk assessment and heavy metal accumulation were evaluated in the muscles of widely consumed Trachurus trachurus, Lutjanus fulgens, Lutjanus goreensis, Acanthocybium solandri, Pagellus bellottii, Scomber colias and Dentex congoensis fish species in Asafo, Ghana. The fish samples were prepared using a wet digestion method and the heavy metals analysis was performed with the flame atomic absorption spectrophotometer (UNICAM 969). The results revealed that Mn, Cu, Zn, Cd, and Pb concentrations were below the permissible values set by several health institutions. The health risk assessment based on non-carcinogenic and cancer factors effect indicates no adverse health effect of fish intake. The results of heavy metal concentrations showed that different varieties of fish could be safe for human intake and the results are anticipated to create alertness among the local people.

Alum, the predominant coagulant in conventional drinking water treatment schemes, has various disadvantages including the production of large volumes of sludge, lowering water pH (requiring pH adjustment using lime), limited coagulation pH range of 6.5 to 8.0, etc. At the Barekese Water Treatment Plant in Ghana, an alternative, the polyelectrolyte – Polyaluminium chloride (PAC) is also used in coagulation but limited information is available on the operating conditions required to achieve better performance than alum-based coagulation. The aim of this study was to determine the optimal coagulant dose, mixing speed and operating pH for enhanced performance in water treatment. The effects on the treatment process of three different sets of mixing speed pairs – 180/40, 180/25 and 150/25 revolutions per minute (fast/slow) – in a pH range of 6.5 to 8.0 were investigated. The mixing speed and PAC dose yielding the best coagulation were 150/25 rpm and 15 mg/L respectively. The optimal pH range for PAC coagulation performance was 7.5 to 8.0.