An Assessment of Heavy Metal Pollution in Sediments of a Tropical Lagoon: A Case Study of the Benya Lagoon, Komenda Edina Eguafo Abrem Municipality (KEEA) — Ghana

Abstract

Background. Elevated concentrations of heavy metals in soil have detrimental consequences on the environment, which translates into damaging effects on humans. Objective. An evaluation was carried out to determine the concentrations of seven heavy metals (As, Cd, Cr, Cu, Hg, Pb, Zn) in soil sediments collected from 12 different stations within the Benya Lagoon in Komenda Edina Eguafo Abrem Municipality (KEEA) in Ghana. Methods. The calibration and concentration measurements of the elements were carried out using a fast sequential hydride generation atomic absorption spectrophotometer. Results. An assessment according to metal concentration in terms of abundance found that Pb registered the highest, while a comparison with standard sediment criteria by USEPA and CBSQG indicated heavy pollution levels of As, Cd, Hg, and Pb. Using Pearson's coefficient matrix, As-Cd had a correlation of 1.000, while Zn-Pb registered 0.858, indicating the same or similar source input for each pair. Both the geo-accumulation index (I eo) and the contamination factor (CF gave the extent of contamination in the order Cd > Pb > As > Hg > Cu > Cr > Zn, while the degree of contamination Cd at the stations was in the order 1 > 3 > 4 > 5 > 6 > 2 > 7 > 8 > 9 > 10 > 12 > 11, indicating Station 1 as the most polluted. The Hakanson index established the order of decreasing threat of a potential ecological risk as Cd > Hg > As > Pb > Cu > Cr > Zn. Discussion. The high sums of the individual potential risks values obtained at the sampling stations point to a possible detrimental effect on the health of inhabitants that use resources directly from the lagoon without treatment, and therefore the need for education to curtail any unanticipated disasters. Competing Interests. The authors declare no competing financial interests.