Nexus Between Urban Landuses and Water Pollution: Fid-Bau Portal

Nexus Between Urban Landuses and Water Pollution

Nnaji, Chidozie Charles / Victory, Chibueze Chekwubechukwu

Urbanization has been severely implicated in the pollution of freshwater resources through the impairment of urban runoff. Studies have linked specific pollutants to certain kinds of urban landuse and land cover. This study combines conceptual and experimental approaches to explore the impact of landuse and land cover on the physico-chemical characteristics of urban runoff in Nsukka, Southeastern Nigeria. Landuse and landcover classification of the area was undertaken using geographical information system and the location of specific landuses that contribute to runoff pollution such as waste dumps, farmlands, mechanic workshops and industrial sources were identified and digitized using global positioning system (GPS). Then runoff water samples were collected and analysed for physico-chemical parameters. Specific contaminants expected in the runoff were predicted based on the pollutants usually associated with these landuse types. The conceptual predictions were augmented with the results of the physico-chemical analyses. Results showed that the landuses were in this decreasing order: bare land (21.8%), residential built-up (19.2%), Commercial built-up (18.6%), Cropland (16.1%), natural vegetation (10.6%), roads/pathways (10.2%) and institutional landuse (3.6%). The major pollutants specific to these landuses are heavy metals, total phosphorus, total nitrogen, turbidity, hydrocarbons and pathogens. According to the laboratory results, Cr, Fe, Hg, Ni, Pb, Cu and As were the key pollutants with concentrations ranging from 0–0.7, 11.74–47.44, 0–10.0, 1.44–2.67, 0–0.50, 0–1.94 and 0.45–2.26.