Evaluation of the Ecological Health Status of Creek Road River Using the Condition Factor and Health Assessment Index of Tympanotanus fuscatus

Abstract

A healthy environment is essential for achieving economic prosperity and eradicating poverty. Creek Road water-sides are characterised by the presence of a boat transport jetty essential for local transportation and trade. Furthermore, this area faces significant environmental challenges due to the dumping of human waste into the water body. This ecotoxicological study aimed to evaluate the ecological health status of the Creek Road River using Tympanotonus fuscatus as a biomarker. The study complements chemical environmental monitoring with bio-indicator-based bio-monitoring to achieve a more holistic ecological health assessment. Based on a literature review on hazardous chemical crude oil spills, the following Target Chemicals (TCs) were selected for the study: lead (Pb), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and polyaromatic hydrocarbon (PAH). The experimental study area was the Creek Road River, while the African Regional Aquaculture Centre (ARAC) was selected as the reference site. In both sites, water, sediment and T. fuscatus were sampled for a comparative study. Water and sediment samples were used to evaluate the Environmental Water Quality Index (EWQI) and sediment quality, respectively. The sampled fish was used for gross anatomical assessment of condition factor (CF) and Health Assessment Index (HAI). The observed internal and external lesions were recorded and scored in terms of the severity of the lesion using the HAI protocol. EWQI of Creek Road River results showed worse outcomes than ARAC, with temperature, dissolved oxygen (DO) and heavy metals failing to meet the Maximum Allowable Toxicant Concentration (MATC) guideline for marine water. Sediment quality showed that Pb and PAH were above the MATC for marine sediment in Creek Road River, while all parameters were normal in ARAC. There was no significant difference in CF and HAI for experimental and reference sites. The study was able to show that there is an ongoing heavy metal contamination of the Creek Road River with a historic spectrum of contamination profile. The CF and HAI results showed a good ecological health status of the River. Though the finding was inconsistent with the expected environmental impact from the water and sediment quality results. It was therefore concluded that a more ecological health-sensitive test tool is needed to make a more assertive statement on the ecological health status of the Creek Road River.