The study was aimed at examining the impact of untreated discharges from artisanal refineries (illegal bunkering), loading and other related activities on the composition, abundance, distribution, and diversity of zooplankton and macrobenthic fauna from four creek channels of the Isaka-Bundu waterfront in Rivers State, a polluted tidal mangrove wetland. Zooplankton and benthic fauna samples were collected monthly from each of the sampling stations for six months (July to December 2021 using standard sampling methods. Margalef (D), Shannon Wienner (H), and Evenness indices were tools used to determine the species richness and diversity respectively using the SPSS statistical package. This study shows that illegal refining activities and other discharges from industrial and human wastes had an unfavourable impact on the zooplankton and macro-benthic fauna community in Isaka-Bundu waterfronts. The effects are reflected in the spatial variations in the composition with more agitation, especially in station 2 in zooplankton and station 3 in macrobenthic fauna, which has a lower number of species and abundance. The majority of indicator species is a validation of this study, the community structure is an insight into the adverse effects of individual and cumulative activities. More impact was observed on the benthos and benthic fauna and this could be due to their exceptional features and location in the aquatic environment. While therefore, this is an indication that creeks are polluted and regular monitoring should be carried out to report the special degradation level of this creek.

This study aimed to investigate the composition, abundance, distribution, and diversity of the phytoplankton community of the Isaka-Bundu waterway in Rivers state, which is a polluted tidal mangrove wetland. Phytoplankton was collected bimonthly from July to December 2021 at high tide from four stations according to APHA methods. The species diversity was calculated using standard indices. The total composition of 334 individual phytoplankton was identified in the 3 stations and control. The total composition of 220 species from 5 Phylum was recorded. This observed decrease in the species diversity and richness could also be attributed to changes in environmental variables due to pollution resulting from industrial effluent discharge into the river which has adversely affected the aquatic biota. Based on these activities, there is an urgent need to carry out a regular study on the phytoplankton community that supports its fisheries in this aquatic environment. The results of this study indicate the characteristic species and compositions of phytoplankton in the Isaka-Bundu waterway in Rivers state. The species abundance and distribution are a confirmation while the composition, and diversity gave an insight into the adverse effect of these cumulative activities. The result showed that the Isaka-Bundu waterway had been extremely polluted.

The behavioural and histological effects of sublethal concentrations (0.0 ml/L, 12.8 ml/L, 25.59 ml/L, 38.39 ml/L, 51.19 ml/L, and 63.99 ml/L) of Xylene were evaluated in African Catfish (Clarias gariepinus) after 28 days of exposure. Physico-chemical parameters such as temperature, conductivity, hydrogen ion concentration (pH), total hardness, total dissolved solids, dissolved oxygen, total alkalinity, ammonia, and nitrate levels in the experiment were monitored using the standard method. Significant variations were observed in the different units except for the controlled unit. Behavioural changes were observed closely during the sublethal toxicity test using standard procedures. The bioassay experiments were repeated three times and the renewable test method was used. concentrations showed histopathological alterations in the gills and liver. Severely deformations were observed at 12.80ml/l, 38.39ml/l), 51.19ml/l, and 63.99ml/l. No form of abnormalities was observed in the fish gill and liver in the controlled unit. Progressive hyperventilation, faster operculum and tail beat movement, erratic movement, gulping of air, and spiralling. jumping, display of vigorous jerky movement suffocation, and loss of reflex were observed in C. gariepinus exposed to higher sublethal concentrations of Xylene. There was a significant dose-dependent variation in parameters in the experiment. In conclusion, xylene caused an alteration in the histopathological parameters and the behaviour of C. garienpinus. Therefore, we recommend the need for realistic regulatory measures and proper monitoring and sensitization on use to stakeholders.