Evaluation du profil métallique et biologique de la pollution de l’air atmosphérique dans la ville province de Kinshasa, République Démocratique du Congo

Abstract

Atmospheric air quality was assessed in Kinshasa from August 2019 to March 2020 by analyzing rainwater and dust in the air to identify mineral and biological pollutants in five sites with high human concentration and motorized traffic (Rond-Point Victoire, Kingasani terminus, Super-Lemba, Limete 7eme Rue, Avenue Nguma and the Bombo-Lumene hunting reserve). Rainwater and dust samples were collected from the roofs of houses and from the leaves of trees over 5 metres high. The concentrations of these pollutants were determined by molecular absorption spectrophotometry. The results obtained showed that the quality of the rainwater collected depends on the particles suspended in the atmosphere. Heavy metals: lead, cadmium and aluminium are present in rainwater in Kinshasa. In descending order of heavy metal concentrations in rainwater per site, we have : Rond-Point Victoire (Al: 43.63±0.75 ppb, Cd: 79.40±0.34 ppb, Pb: 84.88±5.47 ppb) > Kingasani terminus (Al: 44.48±2.5 ppb, Cd: 54.61±0.32 ppb, Pb: 78.93±2.6 ppb) > Limete 7eme Rue (Al: 41.8±2 ppb, Cd: 43.49±2.82 ppb, Pb: 59.11±0.75 ppb) > Super-Lemba (Al: 35.01±4 ppb ; Cd: 40.31±3.74 ppb ; Pb: 49.63±3.3 ppb) > Nguma (Al: 17.13±1.7 ppb, Cd: 14.99±1.32 ppb, Pb: 20.80±1.37 ppb) > Bombo-Lumene (Al: 0.35±0.02 ppb, Cd: 0.42±0.01 ppb, Pb: 0.51±0.01 ppb). For dust, we have : Rond-Point Victoire (Al: 35.7±3.32 ppb, Cd: 69.2±2.69 ppb, Pb: 204.43±4.89 ppb) > Kingasani terminus (Al: 34.08±4.6 ppb, Cd: 66.84±3.63 ppb, Pb: 193.74±4.57 ppb) > Limete 7eme Rue (Al: 23.56±0.51 ppb, Cd: 52.12±6.54 ppb, Pb: 137.45±3.64 ppb) > Super-Lemba (Al: 13,98±0.44 ppb, Cd: 31.96±2.71 ppb, Pb: 96.75±9.81 ppb) > Nguma (Al: 11.23±0.54 ppb, Cd: 46.88±0.85 ppb, Pb: 103.66±6.73 ppb) > Bombo-Lumene (Al: 0.71±0.15 ppb, Cd: 0.32±0.00 ppb, Pb: 1.07±0.1 ppb). The culture of dust in petri dishes revealed 20 plant species belonging to 14 families whose dissemination is through anemochemistry and zoochory, which highlights biological pollution. It is necessary and urgent to develop the monitoring of air quality in Kinshasa.