The journal article on a survey carried out in Zaria, Kaduna state on pollution of water by open waste disposal uses qualitative research method, since the research aims at characterizing the physical qualities of the subsoil, from which the level of pollution by leachate from the open landfills can be determined (Jegede et al., 2012). The survey is qualitative because it is aimed at determining characteristics that cannot be numerically measured such as soil saturation and thickness, bedrock depth, and the distribution and location of conductive fluids (Creswell, 2009). Quantitative analysis is unsuitable for this study as it involves using measurable numerical data that is impossible to collect for this study.
The qualitative data for the study is collected by carrying out a geophysical surface survey of the soil at the municipal waste dumping location. This was done using two techniques namely; the Electrical Resistivity Imaging which involved inserting steel electrodes into the soil sample and the 2D Induced Polarization Profile. Both of these methods were used to measure the electrical sensitivity of the soil (Jegede et al., 2012). After observing the soil characteristics, a decrease in resistivity was attributed to the contamination of the groundwater by leachate from the open landfills. The changeability of the soil although not measured in this survey, is another characteristic that can be used to determine contamination, as an increase in soil chargeability is attributed to an increase in salinity of groundwater due to contamination by leachate.
Another characteristic used to determine contamination is the color change of water collected from the soil from deep blue to light blue which is caused by changes in leachate concentration across the different soil layers. The study also measures the different rates of contamination plume that is determined by the rainfall during different months. It was noted that the plume concentration was higher in dry months such as March and December and lower during the wet months of April to August (Jegede et al., 2012). In conclusion, it is only a qualitative analysis of the geophysical characters of the soil from the dumpsite using the geo-electrical imaging that would have successfully determined the vertical and horizontal leachate concentration, by measuring the resistivity of the contaminated area. This qualitative approach is the only one that fulfills the survey objective of detecting soil pollution in the Zaria area.
References
Creswell, J.W. (2009). Research design: Qualitative, quantitative, and mixed methods approaches (3rd ed.). Sage Publications, Thousand Oaks, CA.
Jegede, S. et al. (2012). Mapping and monitoring of leachate plume migration at an open waste disposal site using non-invasive method. Research Journal of Environmental and Earth Sciences 4 (1), 26-33.