Assessment of physicochemical parameters and heavy metals contamination in Korle and Kpeshie Lagoons, Ghana

Clottey CA, Nukpezah D, Koranteng SS, Darko DA. 2021. Assessment of physicochemical parameters and heavy metals contamination in Korle and Kpeshie Lagoons, Ghana. Indo Pac J Ocean Life 6: 36-50. Lagoons are highly productive coastal systems that could provide natural services to the surrounding ecosystem; however, their pollutions cause adverse changes in their natural environment. Korle and Kpeshie Lagoons in Ghana receive waste from industries and municipal sewage. Controlling and monitoring contaminants in these systems is very important to environmental protection. This study examined the presence of heavy metals (arsenic, chromium, copper, cadmium, lead, and zinc) in sediments, crabs (Callinectes amnicola), and fish (Sarotherodon melanotheron) at Kpeshie and Korle Lagoons. Although lagoons are highly productive coastal systems that offer ecosystem services, their pollution has a negative impact on the surrounding environment. Municipal sewage and industrial waste are dumped into Ghana's Korle and Kpeshie Lagoons. Contaminant monitoring and control in these systems are crucial for environmental protection. The study compared the concentrations of the heavy metals (arsenic, cadmium, copper, chromium, lead, and zinc) in sediments, crabs (C. amnicola), and fish (S. melanotheron) at Kpeshie and Korle Lagoons to the environmental standards set by international organizations like the WHO and US EPA. The sediments from the Korle and Kpeshie Lagoons had traces of contamination in the following metal concentrations in S. melanotheron: cadmium, copper, zinc, lead, chromium, and arsenic, in that order: As, 0.397 ± 0.07; Cd, 1.10 ± 1.31; Pb, 1.227 ± 5.77; Cu, 3.494 ± 4.56; Cr, 5.895 ± 9.76; Zn, 23.225 ± 10.93, and in C. amnicola: As, 0.288 ± 0.07 mgkg-1; Cd, 4.60 ± 2.69 mgkg-1; Cr, 39.521 ± 55.89 mgkg-1; Cu, 31.085 ± 16.26 mgkg-1; Pb, 10.902 ± 12.95 mgkg-1; Zn, 36.042 ± 17.8 mgkg-1. The sediments are severely polluted with Cd and Pb, according to pollution indices like pollution load index (PLI), contamination factor (Cf), and potential ecological risk index (RI). The FAO/WHO-allowable limit for cadmium, chromium, and lead was exceeded in C. amnicola and S. melanotheron. Consumption of C. amnicola and S. melanotheron does not appear to pose a potential non-carcinogenic health risk on an individual's daily basis. The estimated target hazard quotient (THQ) in Kpeshie Lagoon of Cd, Cr, and Pb of the fishery investigated was less than 1.