Potential ecological risk from heavy metals in surface sediment from Lovononkaha Dam in north Côte d'Ivoire (Karakoro/ Korhogo)
Abstract
Lavonnonkaha dam reservoir serve as vital source of water for local farmers. However, ecological and economic zone, has been heavily impacted by the discharge of agricultural waste, leading to significant heavy metal contamination. Ten (10) sediment samples from dam were examined for heavy metals contents in objective potential ecological risk status. their heavy metals concentrations were determined using Atomic Absorption Spectrometry (AAS). Ecological risk assessment was carried out using single (contamination factor, geo-accumulation index, enrichment factor) and multi-elemental (contamination degree, pollution index and modified pollution index) standard indices. The assess ment based on these methods demonstrated that sediments were polluted with Cd and the sediments quality guidelines confirmed these results. The mean concentration of heavy metals (mg/kg) of sediments are as follows: Cu (15,78), Cd (0,89), Zn (6), Al (45535,42), Cr (0,53) et Pb (0,006). The contamination factor (CF) and geo-accumulation index (Igeo) revealed that the all of sediment samples are highly polluted with Cd. The enrichment factor (EF) values ranged from 1,61 to 22,16, with Cd (EF = 15,67) and Cu (EF = 2,04) showing significant anthropogenic enrichment. The modified degree of contamination (mCd) results indicated a moderate degree of contamination in 50% of sites. calculated pollution index (PI) and modified pollution index (MPI) revealing that all the samples were severely polluted. Finally, the risk assessment showed that Cd in the sediments presented a very high potential ecological risk.