Effect of Physiochemical Characteristics and Microbial Water Quality on Tensile Strength of Eichhornia crassipes Harvested from Four Rivers in Southwest Nigeria

This study investigated the influence of microbial water quality and physicochemical characteristics of the aquatic environment supporting the growth of water hyacinth on the mechanical properties of its fibre. Water hyacinth and water samples were collected from four rivers (Igbokoda, Makun, Epe and Badagry) in Southwest Nigeria. The load of faecal indicator bacteria in the water samples and the physicochemical characteristics of the water samples were determined using standard methods. The ASTME 8 standard and computerized Instron testing machine were used to generate load displacement plots from which the ultimate tensile strength were determined. Pearson’s correlation coefficient was used to determine the relationship between the microbial water quality, physicochemical characteristics and tensile strength of the water hyacinth fibres. The findings revealed that the load of total heterotrophic bacteria in the water samples from the rivers ranged from 3.30 to 4.36 log10 cfu/100 ml and E. coli ranged from 3.00 to 4.18 log10 cfu/100 ml. Water from Makun had the highest load of total heterotrophic bacteria counts and E. coli, while water from Epe had the least counts. Temperature of the water ranged from 20.7 to 20.8℃, pH 6.02 to 7.94, electrical conductivity 730 to 1272 µS/cm, total dissolved solids 360 to 648 mg/l and turbidity 0.057 to 0.095 NTU. The maximum tensile stress of the water hyacinth fibres ranged from 0.63 to 1.71 MPa, load at maximum tensile stress 31.23 to 85.23 N and tensile strain at maximum tensile stress 0.09 to 0.25 mm/mm. Pearson correlation revealed that maximum tensile stress had positive relationships with acidity (r = 0.85) and negative relationships with total dissolved solids and salinity (r = -0.99). Tensile strain had positive relationships with total dissolved solids (r = 0.96) and negative relationships with conductivity (r = -0.61), The findings of this study demonstrate that the tensile strength of E. crassipes fibres is not solely a function of species morphology, but a reflection of the ecological and physicochemical conditions of its aquatic environment. Integrating tensile data with water quality parameters may provide insight into how environmental stressors affect the plant’s fibre microstructure and potential usability in sustainable material production.