Contamination Levels of Potentially Toxic Elements and Foraminiferal Distribution Patterns in Lagos Lagoon: A Correlation Analysis

The ecological response of benthic foraminifera to bioavailable Potentially Toxic Elements (PTEs) was evaluated in Lagos Lagoon (Nigeria). We sampled and analyzed PTEs across Lagos Lagoon with the aim to investigate the extent of contaminated sediments, to document their distribution, and to explore the relationship between PTE concentration and the spatial distribution, composition, abundance, and species richness of benthic foraminifera biotas. PTE’s recordings showed a wide range reflecting a diffuse contamination, where Contamination and Enrichment Factor suggest low to extremely polluted sediments. Findings of a previous survey of the benthic foraminifera inhabiting Lagos Lagoon revealed diverse assemblages of benthic taxa, species-specific distribution patterns, gradients of species richness and abundance, and a disjunct distribution of agglutinated and hyaline-perforate/porcelaneous taxa along a pronounced salinity gradient. Correlation matrix analysis shows that except for Selenium, all PTE total concentrations positively correlate with mud and Total Organic Carbon (TOC) and two of the most abundant agglutinated taxa, Ammotium salsum, and Trochammina sp. 1. Moreover, both species display significant positive correlations with CrF4-CoF2-F3-F4-total-CuF4-total-NiF3-F4-total-AlF4-total-FeF3-F4-total-ZnF3-F4-total. On the other hand, both foraminifers correlate negatively with PbF4-SeF3-Setotal. The overall significant positive correlation of these PTEs suggests that they behave as micronutrients when complexed with organic matter. No significant positive correlation with none of the PTEs in any fraction was found for neither species richness nor for the most abundant hyaline perforate species (Ammonia aoteana). Some PTE fractions were found to correlate either positively or negatively with individual species, suggesting that they function as either micronutrients and/or stressors. The resulting Contamination Factor of the PTE total concentrations shows that only a few sample sites can be classified as “moderately” polluted for chromium, zinc, and copper and that all sampled sites are classified as “highly polluted” for selenium. The highest concentrations for Cr, Cu, Ni, and Zn were found towards the industrialized western part, an area that is characterized by moderate to high diversity but low abundances.

Trade on the North Eastern Bank of the Lagos Lagoon: A Focus on Ejinrin Lagoon Market, 1851–1939

This article discusses trade and market activities on the north eastern bank of the Lagos Lagoon. Our particular focus is on the Ijebu lagoon market of Ejinrin. During the period covered by this study, Ejinrin was a meeting point for traders from Lagos and those from southeastern Yoruba hinterland. Traders reportedly attended the market not only from Ijebuland but also from places such as Gbongan, Ile-Ife, Ilesha, Oyo, Ilorin, Okitipupa, Owo, Epe, Orimedu, Atijere and other towns in Yorubaland. Colonial records show that attendance at Ejinrin reached between 20,000 and 26,000 on a market day by the end of the nineteenth century and by 1908, the market was rated as the largest market in the whole of the western provinces of Nigeria. Such was the strategic importance of this market that it supplied Lagos with the bulk of the palm oil shipped overseas during the pre-colonial and colonial periods. Thus, the lagoon market occupied a very important place in the local economy of the Ijebu and that of Lagos. This article is an attempt to understand this aspect of the indigenous economy of Nigeria. It is an attempt to analyze and document the history of commercial activities in this geographical zone of the Lagos (Ijebu) Lagoon. The study relied largely on documentary evidence got from the National Archives, Ibadan and extensive oral evidence collected from those who, at one time or the other, had attended the market.

Communique Issued at the End of the First International Conference on Community, Trade and Religion in Coastal Yorubaland and Western Niger Delta, Held at Adeyemi College of Education, Ondo, from 6–8 December 2016

An international conference was held from December 6 to 8 2016 at Adeyemi College of Education Ondo, with the theme “Mobile Populations, Fluid Boundaries: Community, Trade and Religion in Coastal Yorubaland and the Western Niger Delta.” The conference was sponsored by the European Research Council (ERC), and jointly organized by the University of Birmingham, Osun State University, and Adeyemi College of Education. Over a period of three days, many papers were presented, covering various topics and issues on mythologies, oral traditions, religion, making sense of the Yoruba littoral, economy and intergroup relations in the Gulf of Guinea during the 18th and 19th centuries, trade on the north eastern bank of the Lagos lagoon, history, religion and community formation, moral traditions of the Yoruba and non-Yoruba speaking groups, and many more.

Impacts of Anthropogenic Stressors on Hydrochemistry, Benthic Macroinvertebrates and Sediment Characteristics of the Lagos Lagoon, Nigeria

The anthropogenic impact on the water, benthic macroinvertebrates and sediment grain size of Lagos lagoon was investigated between July and October, 2019. Ten sampling stations were selected based on their importance as likely sources of different forms of anthropogenic stressor to the lagoon. Water temperatures, pH and salinity were measured in situ. Water and benthic samples were collected monthly and analysed using standard methods. Nutrient levels were determined using a spectrophotometer. The hydrochemistry of the stations differed significantly (p<0.05) with the exception of temperature and pH. The sediment grains across the study stations consists basically of sand and mud, with sand dominating the grain type. A total of 502 individuals comprising 3 phyla, 4 classes, 10 families and 11 species was recorded. The phylum mollusca which contributed 92% to the total number of individuals was represented by two Classes; Gastropoda and Bivalvia, with the gastropod Tympanotonus fuscatus having the highest number of individuals (321). Thephylum Annelida represented by one Class, Polychaeta and two Species Nereis sp. and Capitella capitata contributed 6% to the total number of individuals. The class Crustacea, representing the Phylum Arthropoda was the least sampled (7 individuals) constituting about 1.4% of the total population Result showed that different pollution sources have negatively impacted the water chemistry of the lagoon and reduced the diversity and abundance of its benthic macroinvertebrates community. The sedentary nature of this group of benthic fauna could be the major reason why they are most impacted.

Health and Ecological Risks Associated with Heavy Metal Contamination in Surface Soils from Lagos Lagoon Wetlands, Lagos, Nigeria

Wetlands quality and spatial distribution are being threatened by anthropogenic drivers in addition to the emerging threats of climate change. In this study, selected heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in soils from Lagos lagoon wetlands were investigated to assess spatial distribution, ecological and health risks. The data obtained were subjected to statistical analysis using GraphPad 7.0 and SPSS 22.0. Spatial distribution mapping of heavy metals was performed using ArcGIS10.0 (ESRI, Redlands, CA, USA) with Kriging interpolation. Results showed that heavy metals in the soil varied significantly (p<0.05). The contamination factors (CF) were generally low with the values for Cr, Ni, Cu, and Zn very low (<1). The CF values for some of the sampling points showed that the soils are generally moderately contaminated by Pb, Cd and Cu. The modified degree of contamination of Pb (2.35) indicates a moderate degree of contamination while that of Cd (12.60) indicates a high degree of contamination of these wetland soils. The potential ecological risk index (RI) of Pb, Cd, Cr, Ni, Cu and Zn were 70.40, 2264.40, 0.68, 1.55, 13.65, and 2.29, respectively. The RI for Pb, Cr, Ni, Cu and Zn were less than 100, hence, low, while the RI value of Cd was a very high risk (RI ≥ 400). Soils from this wetland’s areas show serious significant potential ecological risk due to Cd. Additionally, children were more susceptible to the potential health risk irrespective of the carcinogenic or non – carcinogenic risk. There were no significant carcinogenic and non – carcinogenic risks for adults and children. This wetland assessment provided important information for policymaking to reduce the potential effects of soil contamination on humans and the eco-environment.

Deterioration and microstructural characterization of reinforced concrete beam buried in lagoon and fresh waters

The effect of the sulphate attack on reinforced concrete structures in Lagos lagoon environment has become a concern for stakeholders in the construction industry. This study investigated the flexural strength and microstructure of reinforced concrete beams for a period of 365 days. Thirty beams with dimension 150 mm × 150 mm × 600 mm were cast using grade 30 concrete with water cement ratio of 0.45 and cured for 28, 90 and 365 days, in both lagoon and fresh water. Flexural strength and microstructural test were carried out. The result showed that the flexural strength of concrete submerged in fresh and lagoon water were 24.6 and 20.3 N/mm2 respectively. The microstructure also confirmed the fact that specimens submerged in the lagoon had more defects and deterioration than the sample cured in fresh water at 365 days.

Pollution Assessment of the Physico-Chemical Properties of the Lagos Lagoon

Lagos lagoon has received wastewater discharged from different anthropogenic sources. Therefore, this study determined the water quality and identified its pollution status. Water quality index (WQI), several heavy metal pollution indices as well as single factor and comprehensive pollution indices were applied. The obtained data revealed that physicochemical parameter varied between 24.00±1.41 and 27.00±0.71°C for temperature; 2.50±2.83 and 10.50±0.71‰ for salinity; 3.90±0.99 and 4.60±0.85 mg/l for dissolved oxygen; 7.26±0.25 and 8.38±0.66 for pH; 3.50±0.71 and 10.00±7.07mg/l for BOD. The results also revealed that sulphate, phosphate and nitrate had means of 10.00±10.45mg/l, 0.85±1.04mg/l and 11.11±17.88 mg/l respectively while Pb, Zn, Cu and Hg had means of 0.25±0.49mg/l, 25.49±44.27mg/l, 1.88±2.94mg/l and 0.00±0.00mg/l respectively. SPI classified pH, BOD, Cu and Zn within the ‘medium pollution’ category while nitrate and phosphate indicated heavy pollution of the lagoon. The PI revealed that Cu and Zn had moderate and slight effect on the aquatic environment respectively while Pb and Hg had no effect on the ecosystem. The mean WQI revealed that the lagoon was classified to be good for aquatic biota despite that HEI and Cd revealed that there was high pollution of heavy metals in the lagoon. The CPI described the lagoon as slightly polluted.

Festac 77: A Black World’s Fair

From January 15 to February 12, 1977, Nigeria hosted an extravagant international festival celebrating Africa’s cultural achievements and legacies on the continent and throughout its diaspora communities. Named the Second World Black and African Festival of Arts and Culture (or Festac 77), it was modeled on Léopold Senghor’s inaugural Festival Mondial des Arts Nègres (World Festival of Black Arts, or Fesman) held in Dakar in 1966 but expanded its Atlantic horizons of Africanity to include North Africa, India, Australia, and Papua New Guinea. Festac’s broader vision of the Black and African world was further bolstered by Nigeria’s oil boom, which generated windfall revenues that accrued to the state and underwrote a massive expansion of the public sector mirrored by the lavish scale of festival activities. Festac’s major venues and events included the National Stadium with its opening and closing ceremonies; the state-of-the-art National Theatre in Lagos, with exhibits and dance-dramas linking tradition to modernity; the Lagos Lagoon featuring the canoe regattas of the riverine delta societies; and the polo fields of Kaduna in the north, celebrating the equestrian culture of the northern emirates through their ceremonial durbars. If Festac 77 invoked the history of colonial exhibitions, pan-African congresses, Black nationalist movements, and the freedom struggles that were still unfolding on the continent, it also signaled Nigeria’s emergence as an oil-rich regional and global power. Festac’s significance lies less in its enduring impact than in what it reveals about the politics of festivals in postcolonial Africa.

Stochastic evaluation of benthic biocoenosis as pollution assessment tool in a perturbed aquatic ecosystem

To analyse the extent of disturbances and determine the state of health of aquatic systems, the integration of several biological effects at different levels of biological organization has been used. One of the most valuable methods of biological effect measurements is the use of ecological surveys at community and population levels. In this study, the distributional evaluation of benthic biocoenosis was undertaken to determine site-specific differences in community assemblage in relation to environmental status of the study sites. Three study locations (Okobaba, Iddo and Tin Can Island) in the western side of the Lagos Lagoon with highest concentrations of human activities were selected. These sites represent areas directly affected by major anthropogenic discharge into the Lagos Lagoon. Samples were collected for six consecutive months (March and August 2014). There was great variation in parameters investigated among the study sites. The concentrations of dissolved oxygen in surface water varied from 3.0- 4.5 mg/L. Chlorophyll a in surface water fluctuated from 0.12- 2.01 mg/L whereas, in sediment values varied from 0.14-1.32 mg/g. Biomass of microphytobenthos (MPB) varied from 1.4-13.2 g. Of the total 841 MPB cells collected the highest population was recorded in Okobaba. Twelve MPB taxa were recorded in the study area. The most important species in terms of numerical abundance was Oscillatoria sp. This organism occurred in all the study stations and recorded a total of 113 cells in the study stretch. A major feature of the population distribution of the MPB taxa in this study is the occurrence of higher number of cells at Okobaba. The number of individuals and the distribution of BMF taxa varied greatly from one study location to another. Of the total 801 individuals collected, 398 were recorded at Okobaba, 316 occurred at Tin Can Island and 18 at Iddo. Unlike the case of MPB organisms, a fewer number of BMF taxa were recorded in the study area. The most important MBF taxon in terms of numerical abundance was Pachymelania aurita. This organism occurred in all the study sites and recorded a total of 162 individuals thereby constituting 20% of the total MBF population collected. The benthic community observed in this study was characterized by low number of individuals and the species of MPB and MBF recorded are known opportunistic species common in stressed environments.

Relationship Between Mercury Concentration in Water, Bottom Sediment And Two Mollusc Species (Crassostrea Gasar and Tympanotonus Fuscatus) From a Lagos Creek in Nigeria

Concentration of mercury was investigated in the flesh and shell of two species of benthic mollusc, Crassostrea gasar and Tympanotonus fuscatus and in water and sediment from Makoko Creek, adjacent to the Lagos Lagoon between January to September 2019. Values obtained for physicochemical parameters in Makoko Creek (water temperature- 28.92±0.1°C; pH- 7.73±0.02; salinity- 14.23±0.05 ppt; dissolved oxygen- 5.34±0.02 mg/l; biological oxygen demand- 7.780±0.1 mg/l and chemical oxygen demand- 12.34±0.02 mg/l) were within the acceptable levels for survival, metabolism and physiology of aquatic organism. The concentration of mercury followed decreasing order as sediment >water >flesh >shell across locations for both species. For all the tested samples of C. gasar and T. fuscatus, biowater accumulation factor in flesh and shell were higher than those of bio-sediment accumulation factor. The coefficients of variance (CV %) in shells were lower than those of the flesh for both investigated mollusc species. It was shown that mercury contents of flesh or shells of C. gasar and T. fuscatu are directly affected by those of water and bottom sediment. J. Bio-Sci. 29(1): 143-151, 2021 (June)