Contamination levels of trace metals (aluminum, copper, cadmium and lead) in water, sediment and two fish species (Marcusenius stanleyanus Boulenger, 1897 and Protopterus dolloi Boulanger, 1900) in the Malebo Pool at Kingabwa (Kinshasa, DR Congo)

Abstract

In recent decades, numerous studies have focused on the level of contamination of aquatic environments, and there has been growing interest
in the consumption of fish resources in relation to health risks. The aim of the present study is to assess the level of contamination of water,
sediment and two fish species (Marcusenius stanleyanus Boulanger, 1897 and Protopterus dolloi Boulanger, 1900) by trace metals (Aluminium,
Copper, Cadmium and Lead) at the Kingabwa fishing station in the Malebo Pool (Congo River). Samples were collected between July and
November 2023. Metal Trace Element (TMEs) levels were determined using an ED- XRF Xepos X-ray fluorescence spectrophotometer. The
results revealed high levels of TMEs in the water, with values of 0.26±0.00 mg/L (Al), 2.53±0.03 mg/L (Cu), 0.18±0.17 mg/L (Cd) and
0.15±0.00 mg/L (Pb), above the WHO standard. The levels recorded in the sediment are below the sediment quality guidelines for the protection
of aquatic life. Toxicological analysis of fish samples showed high overall Cd and Pb levels, compared with the tolerable limits set by the WHO
(Cd: 0.05 mg/kg; Pb: 0.2 mg/kg). This study recommends that particular attention be paid to monitoring the physical, chemical and biological
quality of aquatic ecosystems and their resources, to avoid exposing consumers of fish resources to health risks.