Temporal Variation of Physical and Chemical Characteristics of Water in Selected Locations in Lake Naivasha, Kenya

Abstract

Lake Naivasha is a freshwater lake whose water quality is of great concern because of human and natural influences that affect its water chemistry and limnological characteristics. The main objective of this paper was to determine the temporal variation of physical and chemical characteristics of water in Lake Naivasha. Physico- chemical parameters were studied monthly and collected in triplicates from seven pre-defined stations from February 2019 to July 2019. Samples were collected in triplicates to determine nitrate nitrogen, SRP, TN, TP, ammonium nitrogen, and silicates. Water temperature, conductivity, DO, secchi, and pH were measured in situ using a multimeter probe. The findings of the study showed that the mean temporal variations in TN were 471 μg/L ± 170.61 SD, TP 97.97 μg/L ± 49.06 SD, NO3-N 6.70 μg/L ± 3.55 SD, NH4-N 18.93 μg/L ± 10.91 SD and SiO2 3.18 mg/L ± 2.99 SD. The temporal in situ readings showed a mean temperature of 22.73 °C ± 1.6 SD, DO 8.51 mg/L ± 0.87 SD, and pH 8.13 ± 0.3 SD. Single-factor ANOVA test revealed that temperature, dissolved oxygen, conductivity, pH, TP, TN, and silicates were significantly different between the sampled months (p <.05). The results depict that anthropogenic activities, seasonal shifts, and variation play a key role in determing the lake’s water quality and limnological characteristics. There is a need for monitoring the limnological characteristics of Lake Naivasha basin to understand the water quality dynamics of the ecosystem and to come up with relevant management strategies.