Influence of leachates on geotehnical and geochemical properties of termite mound soils

Thisstudy investigated the influence of leachate prepared from Telfairiaoccidentalis on the geotechnical and geochemical properties of termite moundsoil obtained from the premises of the federal university of agriculture,Abeokuta, south-western Nigeria. The termite mound soil samples were collectedfrom three different locations and each sample collected was contaminated bymixing with leachates in percentage increments of 0% 10%, 15% and 20% of dryweight of the air-dried soil. The soil samples were subjected to Atterberglimits and hydraulic conductivity tests for geotechnical observation and X-rayfluorescence tests for geochemical tests. The range of values for thegeotechnical analyses were obtained as; plastic limit (9.1% – 14.2%), liquidlimit (28.6 % – 61%), plasticity index ((18.2% – 49.5%) and hydraulicconductivity (1.85 – 4.1 x 10-8) cm/sec) with a resultant reductionin the plastic limit, liquid limit and plasticity index values but an increasein the hydraulic conductivity of the samples as the leachate concentrationincreased. The results from X-ray fluorescence analyses after 20% leachatecontamination showed that the major elemental chemical composition for thethree samples were comprised of SiO2 (56.25 – 56.5%), Al2O3(28.42 – 28.50%), Fe2O3 (4.46 – 6.5%), TiO2(1.08 – 1.23%), CaO (1.45 – 1.60%), P2O5 (0 – 0.04%), K2O(0.9 – 6.1%) and MnO (0.02 – 4.7%). There was a marginal alteration of theindices with the values inferring the presence of a minimum composition offeldspar and a major composition of quartz-rich minerals and thus lending morecredence to the presence of silicates as shown from the X-ray fluorescenceresults. It also infers that the termite mounds are predominantly made fromsand materials. The termite soil samples obtained from the aforementionedlocations may not be suitable for engineering works unless stabilizationprocedure is adopted.