In the commune of Masina, as elsewhere in the democratic republic of Congo, the sector of rudology or the systematic study of waste has so far been little or badly known. Thus, technical studies and scientific research must be carried out to better understand this sector and spare the populations from various consequences linked to poor waste management. It is in this logic that is located this study which consists in making an inventory of fixtures on the management of the municipal waste with a view to possible improvement. At the end of the investigations, it appears overall that the solid household waste management system set up in the municipality of Masina is anti-ecological. This is explained by the combination of several variables, in particular: - the absence of a real policy of ecological development of the territory, of good governance and of environmental education/responsibilization of the population; - the ignorance and ecological incompetence of the municipal authorities (77%), the team in charge of waste collection (100%) and the inhabitants of the municipality of Masina (71,4%); - a multifaceted poverty (moral and materiel) and a negligence of the residents which lead them to live in insalubrity; - the use of unsuitable and non-ecological solid waste management methods and techniques (39%). Therefore, it seems urgent that producers of waste and decision-makers question themselves and make amends in order to assume themselves differently as consumer-pays and polluter-pays.

A total of 51 samples of Distichodus fasciolatus (Mboto in Lingala), Mormyrops anguilloides (Monzanda/Nzanda) and Schilbe mystus (Ndangwa/lilangwa) fish, gutted and separated from the gills, were captured from the Kinsuka fishing site in Pool Malebo on the Congo River in Kinshasa to determine lead and cadmium concentrations, and to assess the health risk associated with their continued consumption. After spectrophotometric analysis with HACH - DR 2400 in accordance with the laboratory's operating procedure, it appears that all the species of fish analyzed are contaminated with lead and cadmium at concentrations far above the European Union edibility standard. The continued consumption of 14.24 grams per day of fish from the Kinsuka fishing site poses the obvious risk of developing chronic disease throughout life, especially in children. The hazard quotients and the associated hazard quotients, whether for children or for adults, are far greater than 1. This risk could become even worse when the purchasing power of consumers is improved in the future. It is up to the government to ban the consumption of these fish and to take binding measures to reduce the contamination of aquatic ecosystems, to introduce national standards for the discharge of industrial wastewater and for foodstuffs intended for human consumption.

Fish Tilapia nilotica, Mormyrops anguilloides and Schilbe mystus, captured at port Socopla-Lomata on the Congo River in Mbandaka were analyzed by X-ray fluorescence spectrometer, brand Xepos III in accordance with the laboratory’s operating mode; to assess lead, cadmium and mercury contamination. The results showed concentrations higher than the edibility standards of the European Union and the concentrations observed in the water of the fishing site. The species Mormyrops anguilloides accumulates more cadmium while lead and mercury are more accumulated in Tilapia nilotica.