The hydrochemistry, sediment and benthic macroinvertebrates of some anthropogenically stressed parts of Lagos Lagoon, Nigeria

The introduction of biodegradable wastes into the coastal waters has altered the water and sediment qualities and constituted stressors to the aquatic biota. This research was carried out to evaluate the impact of anthropogenic inputs on the water, sediment, and benthic fauna of the Lagos lagoon. Six sampling locations were studied from July to December, 2023. Water as well as benthic samples were collected monthly at each study station using the Hydrobios water sampler and the Van-veen grab respectively, and analyzed in the laboratory following standard procedures. The analysis of variance (ANOVA) showed that there was no significant difference (P> 0.05) in values of the pH, salinity, The sediment particle composition was dominated by mud. A total of 597 benthic macrofauna individuals comprising 3 Phyla, 4 Classes, 4 Orders, 8 Families, 8 Genera and 8 Species were sampled. The gastropods, Tympanotonus fuscatus dominated the benthic Macrofauna assemblage of the study area accounting for 56.0%. The Phylum Arthropoda was represented by one species Clibanarius africanus, recorded the least number of individuals, which contributed 0.05% of the total number of individuals collected during the Sampling period. The low abundance of the filter-feeding bivalves, the highly sensitive arthropod species as well as Pachymelania aurita in the study area may be indicative of stressed nature of the area. The existence of benthic macroinvertebrates must be guaranteed by ensuring healthy water bodies. This is possible through the implementation of environmental protective measures, which should be on the bases on the baseline condition of these pollution hotspots of the Lagos lagoon.