Heavy metal exposure risk associated with ingestion of Oreochromis niloticus and Coptodon kottae harvested from a lacustrine ecosystem

Abstract

Lacustrine ecosystems have not been widely assessed for heavy metal contamination and associated health risks; yet, they could be accumulating these contaminants to the detriment of aquatic organisms and communities relying on them for various aspects. The water quality index (WQI) and concentrations of heavy metals including As, Cd, Co, Cu, Cr, Fe, Mn, Ni, Pb, and Zn in water, sediment, Oreochromis niloticus, and in the endemic and endangered Coptodon kottae in Lake Barombi Kotto in Cameroon were determined to evaluate fish heavy metal bioaccumulation, and heavy metal exposure risk posed to communities consuming these fish species. The WQI of the lake was found to be excellent with heavy metal concentrations that were lower than what was obtained in the sediments and fish samples. Mean heavy metal concentrations in sediment ranged from 0.86 ± 0.03 mg/kg for Cd to 560.1 ± 11.15 mg/kg for Fe. In both fish species, Fe, Mn, and Cu had the highest concentrations. Though the heavy metal concentrations in the lake water were low, heavy metal bioconcentration factors for both fish species were very high ranging from 1.6 for Fe to 1568 for Mn. The concentration patterns of heavy metals in the organs of both fish species followed the order bones > gut > muscle. Consumption of these two fish species contributes less than 1.0% of the permissible tolerable daily intake (PTDI) and provisional tolerable weekly intake (PTWI) of these metals with lead (Pb) having the potential to exceed permissible exposure levels when high amounts of these fish are consumed by adults.

Limnology of the Ndongo stream (South-West Cameroon): wastes management, water physicochemical quality and phytoplankton species richness

“…All the pH values were within the optimum range (6.5 -8.5) for good aquatic productivity. Water bodies of the monomodal equatorial agroecological zone of Cameroon have an alkaline tendency as documented other limnological studies; the Benoe stream [6], the Lake Barombi Kotto [5], the Tiko agro-industrial complex [8].…”

“…Inland waters have a very rich biodiversity including viruses, bacteria, fungi, algae (periphyton and phytoplankton), macrophytes, protozoans, invertebrates (rotifers, flatworms, nematodes, annelids, sponges, molluscs, crustaceans and insects) and vertebrates (fishes, amphibians, reptiles, birds and mammals). These aquatic organisms interact with each other and abiotic factors to guarantee a sustainable ecosystem [5]. The aquatic biota is closely linked to water properties and changes in water abiotic variables will affect their population structure.…”

“…Contaminants find their way into the aquatic system through leaching, run-off, spray drift, soil erosion and volatilisation wherein they exhibit toxic effects on non-target organisms [23]. Aquatic pollutants such as heavy metals are able to accumulate in water, sediments and fish such as Oreochromis niloticus and Coptodon rottae [5]. Moreover, agricultural pesticides have been reported to be very risky to the aquatic ecosystems, modelling moderate to high risk to water, fish, Daphnia and primary producers [24][25][26] as well as amphibians [27,28].…”

Assessment of Pollution Stae of Beire Lake in Sri Lanka Using Water Quality Index, Trophic Status and Principal Component Analysis

“…Development of Water Quality Index (WQI) models has proved to be an effective tool to comparatively understand the effect of multiple water quality variables by utilizing aggregation functions (Egbe et al, 2023, Menberu et al, 2021, Uddin et.al, 2021, Hamed et.al, 2018. The primary concept of WQI was rst introduced by Horton (1965), which has been accepted worldwide and modi ed over time to suit the application.…”