Preliminary investigation on the occurrence and health risk assessment of antibiotics in cultured tilapia retailed at a commercial outlet in Tema, Ghana.

In Ghana, Nile tilapia is one of the most commonly cultivated fish species. Bacterial infections, which mostly occur in intensive fish farming, are considered to be the most significant health issue facing these culture systems in Ghana's aquaculture industry. To prevent, and treat bacterial infections and promote fish growth, antimicrobials are often used, and in most cases at unregulated doses. However, this misuse and neglect of withdrawal durations for such antimicrobials may result in drug residues showing up in fish edible tissue, posing a risk to human consumers. To evaluate the risk to consumers, this study screened for antibiotic residues in popular tilapia fish sold at a retail outlet in Tema. Using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC/MS/MS), the study analysed the levels of 12 antibiotics present in 24 tilapia samples sold at a retail outlet in Tema. Erythromycin, tetracycline, oxytetracycline, and amoxicillin were detected at varying levels, with frequencies of 20.8 %, 62.5 %, 58.3 %, and 54.2 %, respectively. The highest concentration of 3.521 ± 0.32 µg/kg was found for oxytetracycline, while erythromycin had the lowest concentration (0.276 ± 0.11 µg/kg) in the samples. According to the study, the levels of antibiotics detected in the sampled tilapia were lower than the maximum residue limits (MRL) recommended by the WHO. Additionally, both the hazard quotient (HQ) and hazard index (HI) values were less than one. Therefore, consuming retail farmed tilapia purchased from the commercial outlet in Tema metropolis was deemed to pose no significant risk to human health. However, regular monitoring of antibiotics and other contaminants is necessary to minimise their potential impacts on human health.

A comparative study of the pollution status of Sakumo II and Muni lagoons in Ghana.

The pollution status of Sakumo II and Muni Lagoons and Mamahuma and Gbagbla Ankonu feeder streams, which feed Sakumo II along the coast of Ghana, were assessed and compared. As expected of saline waters, pH values of both lagoons fell within a slightly neutral to saline range whilst, the feeder streams were moderately saline. Conductivity distribution also showed saline (>5.0 mS cm(-1)) characteristics of the lagoons, while, the feeder streams are brackish (1.5-5.0 mS cm(-1)). DO concentrations in both lagoons indicated a wide variation. Relatively high BOD and nutrients content of Sakumo II and the feeder streams suggested that, Sakumo II and its feeder streams are moderately to grossly polluted. However, Muni Lagoon was characterized by relatively low BOD and nutrients content suggesting relatively low anthropogenic impact. The ionic dominance patterns for Sakumo II and Muni Lagoons were: Na(+) > Mg(2 + ) > Ca(2 + ) and Cl(-) > HCO(3)(-) > SO(4)(2-), Na(+) > Ca(2 + ) > Mg(2 + ) and Cl(-) > HCO(3)(-) > SO(4)(2-), respectively. Using water quality index (WQI), Sakumo II was found to be grossly polluted and requires mitigation measures, while, Muni Lagoon was of fairly good quality and requires monitoring.