Great Kwa River Research Articles

Assessment of Heavy Metal Contamination in Shrimp and Water from the Great Kwa River: Implications for Human Health and Aquatic Ecosystems

The aftermath of heavy metal pollution can be hazardous to humans, considering the level of consumption of shellfish in riverine areas - which is relatively high. There is a growing concern about the quality of aquatic food (e.g. periwinkle and shrimp) in several parts of the world. The determination of toxic elements in food has prompted studies on toxicological effects of heavy metals in foods. Due to man’s industrialization activities such as oil exploration, the levels of toxicants in marine environments have increased over the years. This study aimed at evaluating heavy metal contents (lead, cadmium, nickel, manganese, chromium and copper) in shrimp and water obtained from Great Kwa River, Calabar, Cross River State, Nigeria. Fresh shrimp and water samples were collected from the river in Calabar metropolis, Cross River State. In the sample preparation, the soft tissue (edible part) of the shrimps were extracted, dried in the oven (at 80°C) for 72hours then, after which the weights of the shrimps and water from each sampling point were measured. Digestion of the samples were carried out before an Atomic Absorption Spectrophotometer was used to determine the concentrations of the heavy metals. Graph pad Prism Version 7 was used for statistical analysis and Microsoft Excel Application. The results indicate contamination of both the shrimps and water from the Great Kwa River by some heavy metals, which also pose a health risk to aquatic ecosystem and humans. Among the heavy metals studied, chromium had the highest concentrations in both shrimps (30.07 ± 0.67ppm) and water (27.68 ± 0.34ppm). The heavy metals were found in higher concentrations in the shrimp than in water, except for manganese which had a significantly (p<0.05) higher concentration in water (15.05 ± 0.67ppm as against 14.02 ± 0.93ppm in shrimp). Certain minerals have biological uses, but concentrations above recommended levels become detrimental to consumers. The levels of some of these heavy metals in this study, call for more investigation and regulation of their anthropogenic sources in order to reduce risk of public health issues.

Effects of Municipal Waste Discharge and its Re-Suspension on Water Quality in the Great Kwa River Estuary, Cross River State, Nigeria

Effects of Municipal Waste Discharge and Its Re-suspension on Water Quality in the Great Kwa River Estuary, Cross River State, Nigeria investigates the impact of municipal waste discharge and its re-suspension on water quality in the estuary. The research was conducted at two locations, Obufa Esuk, and Idundu, utilizing heavy metal analysis and Pollution Load Index (PLI) calculations during dry and wet seasons. Water samples were collected and analyzed using standard methods for heavy metal detection, including atomic absorption spectroscopy, while the PLI was calculated based on the concentration of pollutants relative to background levels. Results show that copper (Cu) and zinc (Zn) levels at both sites are within World Health Organization (WHO) safety limits. However, lead (Pb) and cadmium (Cd) concentrations are significantly high. At Obufa Esuk, cadmium reaches 0.76 mg/L in the dry season and 0.7 mg/L in the wet season, exceeding the WHO limit of 0.003 mg/L. Lead levels are elevated but below the WHO threshold of 0.01 mg/L. At Idundu, cadmium peaks at 0.85 mg/L in the dry season and 0.73 mg/L in the wet season, with lead concentrations also exceeding safe limits. These elevated metal levels are linked to severe pollution from municipal waste discharge and its re-suspension. The PLI values indicate moderate pollution at both sites, with Obufa Esuk showing values of 2.30 and 2.25, and Idundu showing 1.85 and 2.15. This pollution is associated with high turbidity and Total Dissolved Solids (TDS). The study highlights the urgent need for improved waste management practices, recommending upgrades to treatment facilities, stricter regulations, enhanced runoff, and erosion management, regular water quality monitoring, public awareness campaigns, and better stakeholder collaboration to protect water quality and public health in the Great Kwa River estuary.

Dynamics in a tropical meso-tidal river: Great Kwa River, southeastern Nigeria (Gulf of Guinea)

Dynamics in a tropical meso-tidal river: Great Kwa River, southeastern Nigeria (Gulf of Guinea)

An Assessment of the Effect of Pollution on Zooplanktons in Calabar Great Kwa River, Nigeria

Aim: Zooplanktons in the Calabar Great Kwa River were studied to assess the effect of pollution from human activities around the river on their respective abundance.
 Place and Duration of Study: Samples were collected at the Esuk Atu and Esuk Atimbo stations of the Calabar Great Kwa River. Identification of Zooplanktons was carried out at the Laboratory of the Department of Genetics and Biotechnology, University of Calabar, Calabar, Nigeria.
 Methodology: Collected samples were preserved, transferred to the laboratory, identified using a dissecting microscope and classified according to their different taxonomical groups.
 Results: The Results showed that zooplankton abundance and distribution recorded in the stations were low due to pollution and interference from high human activities around the river such as domestic solid wastes, sewage waste waters, industrial effluents, pesticides, sand mining activities, hydrocarbons and other toxic substances. In Esuk Atu, the total abundance of zooplanktons in the periods of sampling were 12, 6, 3 and 11, while the numbers of taxa represented in the periods of sampling were 4, 3, 1 and 4. In Esuk Atimbo, the total abundance of zooplanktons in the periods of sampling were 7, 5, 9 and 10 while the numbers of taxa represented in the periods of sampling were 3, 3, 3 and 2. The zooplankton taxa identified in station 1(Esuk Atu) are Cladoceran (38%), Ostracoda (22%), Copepoda (19%), Rotifera (12%), Lepidoptera (6%) and Protozoa (3%). The zooplankton taxa identified in station 2 (Esuk Atimbo) are Copepoda (26%), Cladoceran (23%), Nemata (23%), Lepidoptera (16%), Rotifera (6%), Polycheata (3%) and Paguridae (3%).
 Conclusion: These findings necessitate the need for the regulation and control of pollution from human activities around the Calabar Great Kwa River so as to ensure that the river is free from harmful contaminants thereby preserving the zooplanktons and other relevant organisms.

Studies on the bioactive elements and nutrients distribution in surface sediments of Cross River Estuary, Calabar River and Great Kwa River, South - South Nigeria

Studies on the bioactive elements and nutrients distribution in surface sediments of Cross River Estuary, Calabar River and Great Kwa River, South - South Nigeria

Studies on the bioactive elements and nutrients distribution in surface sediments of Cross River Estuary, Calabar River and Great Kwa River, South South Nigeria

Studies on the bioactive elements and nutrients distribution in surface sediments of Cross River Estuary, Calabar River and Great Kwa River, South South Nigeria

Flash Flood Risk Assessment of the Great Kwa River Basin Using Analytical Hierarchy Process

Flash Flood Risk Assessment of the Great Kwa River Basin Using Analytical Hierarchy Process

The Distribution and Seasonal Variation of Zooplankton Species of the Great Kwa River, Calabar, Nigeria: A Reassessment Approach

Background: Human activities adversely affect the distribution and diversity of zooplankton. They are diverse group of organisms with little or no locomotive ability and quickly respond to changes in their environment. This research was aimed at providing updated information on the distribution and seasonal variation of zooplankton in Great Kwa River.
 Materials and Methods: Two sampling stations (S1- Obufa Esuk and S2- Esuk Atu) were mapped along the river bank, samples were collected using plankton net of 55µm mesh size and preserved in 4% formalin. Species were identified using taxonomic keys. Data were analyzed using ecological indices.
 Results: The results revealed 12 taxa; belonging to 38 species. Tintinnida, Protozoa, Cladocera, Copepoda were 23.1%, 18.5%, 15.4% and 13.3% respectively. The lowest taxonomic groups were Diptera, Foraminitera, Atenatadata and Trichoptera having 1.85% for each order. The highest species was recorded in S2 having 31 species. In both Stations Ascampbelliella acuta was dominance over other species. Shannon-Weiner index (H) were 2.997 and 2.40 in S2 and S1 respectively. The evenness index were 0.576 and 0.547 for S1 and S2 respectively. Margalef,s diversity index were 8.171 and 4.111 for Esuk Atu-S2 and Obufa Esuk-S1 respectively. Zooplankton species were abundant in wet season than dry season.
 Conclusion: This present study provide updated information on the zooplankton distribution, diversity and seasonal variations of the Great Kwa River. The high dominance of Tintinnida in this study indicates a natural linkage between nano-planktons and macro-planktons in the food webs of the river.

Climate Change Mitigation Potential and Carbon Stock Assessment of Mixed Mangrove Forest, of the Great Kwa River, Nigeria

Climate Change Mitigation Potential and Carbon Stock Assessment of Mixed Mangrove Forest, of the Great Kwa River, Nigeria

Evaluation of Pollution Load: Heavy Metal Contents and Physiochemical Properties of the Great Kwa River, Calabar, Cross River State, Nigeria

Background and Objectives: Human activities can increase the amount of pollutants in the environment leading to water pollution. The contamination of surface water and sediments by heavy metals can result in adverse health conditions of humans, due to the bioaccumulation of metals. This study seeks to assess the pollution load of some heavy metals and physiochemical properties in Great Kwa River.
 Methods: Water samples were collected once a month from three stations within four selected months in wet and dry seasons. Samples were preserved by adding 10 ml of 6 N Nitric acid and stored at 5oC. Laboratory investigations were conducted and data analyzed statistically.
 Findings: The mean pH, dissolved O2, biological O2 demand, conductivity, NO3, NH4 and temperature were 7.44±1.24, 5.58±0.92, 0.957±0.002, 32.84±2.941, 0.1030±0.1701, 0.113±0.018 and 28.2±1.48, respectively during wet season. Mean concentration of Cu, Fe, Cr, Mn, Zn, Ni are 0.225±0.003, 0.489±0.009, 0.068±0.016, 0.102±0.006, 0.794±0.003, 0.031±0.001, respectively during the wet season. Mean concentration of metals in the river during the wet season were ranked in descending order as Zn > Fe > Cu > Mn > Cr > Ni. Iron (0.489±0.009 mg/l and 0.438±0.003 mg/l), chromium (0.068±0.016 mg/l and 0.055±0.008 mg/l), nickel (0.031±0.001 mg/l and 0.025±0.002 mg/l) were higher than Nigerian standard for drinking water in both seasons. The contamination factor of heavy metals in station 3 were 2.14, 1.56, 1.09, 0.89 for Fe, Cr, Ni, Zn, respectively, indicating moderate contamination. The pollution load index in stations 1, 2, 3 were 0.262, 0.537, 0.981, respectively.
 Conclusion: The present study provided base-line information on the pollution levels and physiochemical properties of the river. The river was not highly polluted by heavy metals except iron, chromium and nickel that were found above the recommended standards. However, drinking of water from the river over one’s lifetime is not advisable due to detrimental health hazards.

ASPECTS OF REPRODUCTIVE BIOLOGY AND ABUNDANCE OF AFRICAN BONYTONGUE (HETEROTIS NILOTICUS) IN GREAT KWA RIVER, NIGERIA

This study was conducted to evaluate some aspects of the reproductive biology of the African Bonytongue Heterotis niloticus from the Great Kwa River, Cross River State Nigeria with the view to encourage conservation and rational measures for sustainable management of the species. A total of 62 matured H. niloticus were sampled and their gonadosomatic index (GSI), hepatosomatic index (HSI), condition factor, fecundity and egg diameter (mm) were studied in other to determine the spawning season of the fish. Gonadosomatic index and hepatosomatic index showed an inverse relationship during spawning seasons. Total length (TL-cm) ranged between 47.1 cm – 76.2 cm and total weight (TW – g) ranged between 4300g - 1169g with sex ratio of 1:1.2 (male: female) revealing a dominant female population. Fecundity ranged from 511 oocytes (48.4cm TL; 1.69 kg wt, 5.9g gonad weight) to 7822 oocytes (69.3cm TL, 3.11kg wt. 14.9g gonad weight). The regression equation derived from the scattered diagram in the relationship between fecundity and total weight, total length gonadosomatic index and length-weight is; F= 6.6231TW0.837, R2= 0.2456; F= 5.1112TL1.6367, R2= 0.1606; F= 10680GSI0.9276, R2= 0.6567; TW= 0.4072TL2.0987, R2= 0.7533, the relationship were significant (p < 0.05). Fecundity and ovary weight relationship showed a positive correlation coefficient of 1. The highest egg diameter (0.92±0.01) was recorded in May and other months with corresponding high gonadosomatic index performance to confirm spawning period. In view to encourage conservation by investigating measures for sustainable management of the species, this study observed that H. niloticus spawns throughout the year.
 Ikot, N. U. | Department of Zoology and Environmental Biology, University of Calabar, P.M.B.1115 Calabar, Nigeria

Nutrient biogeochemistry in the Cross River estuary system and adjacent Gulf of Guinea, South East Nigeria (West Africa)

The Cross River, Calabar River, and Great Kwa River together form a network of an estuary system otherwise known as the Cross River Estuary system (CRES). Studies of dissolved nutrients and water mass dynamics were conducted mainly in February 2017. Nutrients measured included NO3−, NO2−, NH4+, dissolved inorganic phosphate (DIP), total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), dissolved organic nitrogen (DON), dissolved organic phosphorus (DOP) and dissolved silicate (DSi). The rivers were enriched with DSi and depleted of DIP. Dissolved nutrients were more elevated in the Great Kwa River than Cross River and Calabar River. The levels of DSi and DIN were less than average global concentrations, and that of river estuaries affected by anthropogenic activities. DON was the major form of TDN in the Calabar River estuary, and averagely accounted for 68–76% of TDN pool, while DOP accounted for ∼ 54–75% of TDP pool. Similarly, DON was the dominant form of TDN, and represented 75–84% of TDN pool in the Cross River estuary. In contrast, TDN was dominated by DIN, which accounted for 76–84% of TDN pool, while DIP accounted for 56–61% of TDP pool in the Great Kwa River estuary. There was a switch from DOP (67% of TDP) dominated river water to DIP (67% of TDP) dominated estuarine water in the Cross River estuary, due to enrichment of DIP in the lower Cross River estuary. The adjacent shelf was dominated by DON (58% of TDN) and DIP (70% of TDP). Based on nutrient molar ratios, primary production was strongly limited by DIP, especially in the riverine regions, and switched to DIN limitation in the adjacent shelf. Nutrients in the CRES behaved non-conservatively, and were affected by biogeochemical and physical processes. Nutrient budgets were estimated using the classical LOICZ steady−state box model. Atmospheric deposition of dissolved nutrients was very limited compared to riverine supply. The exchange time of water between the CRES and adjacent sea was ∼ 3.5 days, and may have affected biotic processes and nutrient transport. The CRES was an important source of DIP (137 × 103 moL day−1), DOP (92 × 103 moL day−1) and DON (4849 × 103 moL day−1) to the adjacent shelf, which was respectively 7, 4 and 2 times higher than the total riverine input. The ecosystem metabolism of the CRES, inferred from the ΔDIPsystem and ΔDINsystem indicated that respiration of organic matter was higher than primary production with respiration rate of −15.7 × 106 mol C day−1 (−58 mmol C m−2 day−1), while nitrogen metabolism was −3.8 × 106 mol N day−1 (−14 mmol N m−2 d−1), suggesting that the CRES was heterotrophic, and denitrifying more than nitrogen fixation during this study.

Comparative Studies of Spawning Potentials in Female African Bonytongue Heterotis niloticus (Curvier 1829) between Cross River and Great Kwa River, Nigeria

The spawning potentials of Heterotis niloticus from Great Kwa River and Cross River was compared in a twelve-month study. Forty-nine female H. niloticus was sampled from Cross River and thirty four from Great Kwa River from January to December 2014. Gonadosomatic index (GSI), fecundity and histological examinations were investigated in the Institute of Oceanography laboratory. Each month of this study recorded at least one female specimen with eggs at different stages of development. In Cross River, the months of August and September recorded one hundred per cent female with eggs, while Great Kwa River exhibited such performance in July, an indication of spawning activities by the fish. Cross River had a major GSI peak in July with a minor one in August, but Great Kwa River did not exhibit any significant GSI peak throughout the study, and no significant difference in GSI between the rivers when compared with T-test (0.22; P>0.05). There was a significant difference (0.02, P<0.05) in fecundity of H. niloticus between the population in Cross River and Great Kwa River. Regression analysis of fecundity and body weight showed a positive correlation (P<0.05)(r=0.3686). Histological changes in the gonad of the fish showed no disparity between the rivers. H. niloticus has the ability to spawn all year round, but in the Cross River, the fish has high reproductive potentials than those in the Great Kwa River.

Sexual dimorphism in black jaw tiliapia (Sarotherodon melanotheron) and banded jewelfish (Hemichromis fasciatus) from the Great Kwa River, Calabar, Nigeria

AbstractIn this study, the pattern and magnitude of sexual dimorphic differences have been investigated in black jaw tilapia (Sarotherodon melanotheron) (n = 160; 74 males and 86 females) and banded jewelfish (Hemichromis fasciatus) (n = 120; 42 males and 78 females) from the Great Kwa River, Calabar, Nigeria. Fish samples were collected between July and December 2015. Fourteen morphometric variables, including body weight, total length, standard length, body depth, cheek depth, pre-orbital length, postorbital length, pectoral fin length (right and left), pelvic fin length (right and left), head length, gonad weight, eye diameter and four meristic variables, including number of pectoral fins (right and left) and number of pelvic fins (right and left), were taken using standard methods. Size-adjusted morphometric measurements subjected to step-wise discriminant function analysis were used to determine predictor variables to morphologically differentiate sexes for both species; magnitude of dimorphism between sexes was estimated using percentage classification accuracy of the discriminant function analysis. From the discriminant function analysis, the pectoral fin length and gonad weight positively contributed significantly to morphometric dimorphism (magnitude=69.2%) in male and femaleS. melanotheronsuggesting adaptation for reproductive function; while forH. fasciatusthe body depth and standard length were important contributors to sexual dimorphism (magnitude=84.2%) suggesting size dimorphism for aggressiveness, territorial behavior and improving swimming performance. Overall, our results indicate that the different magnitude of sexual dimorphism between the two species could be attributable to the type and functional role of sexual dimorphic traits.

Possible Impacts of Wastewater Discharge fromthe University of Calabar Teaching Hospital on the Biota of Great Kwa River, Nigeria

Possible Impacts of Wastewater Discharge fromthe University of Calabar Teaching Hospital on the Biota of Great Kwa River, Nigeria

Lipid Biomarker Analysis of Suspended Particulate Matter from the Great Kwa River, SE Nigeria: Origins and Environmental Implications of Biogenic and Anthropogenic Organic Compounds

Biomarkers found in natural waters, sediments, soils, fossils, crude oil, and coal can be unambiguously linked to specific precursors biosynthesized by biota. Petroleum and its refinery products carry their biomarker information into the environment when they are released by pollution. Lipid biomarkers can be used to assess the environmental status of an ecosystem and the degree to which it has been influenced by biogenic and anthropogenic inputs. The marine ecosystem of the southeastern Niger Delta of Nigeria is receiving new attention due to increased human and industrial development and the consequent potential health effects. Suspended particulate matter (SPM) from the Great Kwa River was characterized using biomarkers to assess such pollution. The total organic carbon contents of SPM from the river at low and high tide was 12–50% (avg 34.75%) and 16–28% (avg 24.25%), respectively. The lipid biomarkers identified using gas chromatography–mass spectrometry were mainly n-alkanes, n-alkan-2-ones, triterpenoids and minor amounts of aromatic compounds. The n-alkanes ranged from C 17 to C 35, with an odd/even predominance and C max > 27, indicating a mixed origin from higher plant wax, biodegraded detritus, and petroleum. The n-alkan-2-ones in most samples ranged from C 16 to C 33, with C max = 31, also supporting an input from vascular plants dominating the riparian zone along the river. The triterpenoids, mainly taraxerone, taraxerol, α- and β-amyrins, and friedelin, also derived from higher plants (angiosperms). Minor amounts of aromatic hydrocarbon derivatives from α- and β-amyrins were present and are likely the result of different diagenetic processes. The presence of trace fossil fuel-derived hopanes with an unresolved complex mixture of branched and cyclic hydrocarbons supported a minor petroleum product input to the SPM of the Great Kwa River.

Nutrient and energy composition of flesh, limbs and carapace of Callinectes amnicola (Blue Crab) from Great Kwa river, South East Nigeria

This study compared some nutrient and energy levels in three body parts of Callinectes amnicola using AOAC methods. Fresh crab specimens were collected from Great Kwa River landing site in Calabar- Nigeria. Results showed that C. amnicola is rich in nutrients, which were unevenly distributed across the body parts. For proximate, moisture was the most predominant (71.50±0.10g/100g- 81.40±0.01g/100g), the dry matter representing about one-fourth the total body weight. Protein and fat recorded highest values in the flesh (36.30±0.01g/100g and 24.54±0.02g/100g, respectively) and least in the carapace (30.30±0.02g/100g and 12.59±0.01g/100g, respectively) (p<0.05). On the contrary, the flesh had the lowest carbohydrate (29.82±0.02g/100g), ash (7.26±0.02g/100g) and fibre (1.91±0.01g/100g) contents, which showed highest values in the carapace (40.10±0.10g/100g, 13.17±0.02g/100g and 3.70±0.10g/100g, respectively). Energy value was generally low (4.50±0.09kcal/g-5.79±0.36kcal/g). For minerals, sodium (139.25±0.36mg/100g-154.46±0.08mg/100g) and calcium (105.46±0.01mg/100g- 143.53±0.06mg/100g) were the most predominant. The micro-mineral elements iron and zinc also occurred in appreciable quantities, with the highest contents in the flesh (16.42±0.10mg/100g and 4.47±0.06mg/100g, respectively) and lowest in the carapace (9.56±0.06mg/100g and 2.53±0.12mg/100g, respectively). The flesh, limbs and carapace of C. amnicola are a significant source of nutrients. Toxicological and biological investigation should consider possible use of powdered nutritious exoskeleton of C. amnicola as nutraceutical agent.

Parasites of crayfish (&lt;i&gt;P. clarki&lt;/i&gt;) and lobsters (&lt;i&gt;Macrobrachium vollenhovenic&lt;/i&gt;) as indicators of metallic pollution in great, Kwa river, Nigeria

Studies on parasites of crayfish and lobsters as indicators of metal pollution in Great Kwa River, Nigeria was evaluated using appropriate instruments for determination of Physicochemical parameters and detection of metals. Formol ether centrifugation method was used for isolation of parasites. A total of 150 crayfish and lobsters were analyzed for metals and tested for parasites. All samples of crayfish (100%) and 136 (90.66%) lobsters were positive with parasites. The distribution of parasitic infection in crayfish from the 5 sampling zones showed Paragonfmus uterobilateralis prevalence 6.0%, 8.7%, 15.3%, and 10.0% from zones 1-4 respectively and crayfish leech prevalence of 10.3%, 16.0% and 20.0% from zones 3-5 respectively. The distribution of parasites in Lobsters showed Polymorphus botulus , 3.3%, 6.0%, 3.6%, and 8.7% prevalence from zones 1-4 respectively. Nicothoic astaci , prevalence was 2.0%, 15.3% and 5.0% from zones 2-4 respectively. Prevalence of Hysterothylacium sp of 2.0% was observed in zone 3 while that of Porospora gigantic was 3.7% in zone 5. Parasite intensity ranged from 2 to 6. Metals detected included Lead (Pb). Copper (Cu), Iron (Fe), Cadmium (Cd), Asenium (As) and Zinc (Zn) with Iron being the commonest. Some parasites with high prevalence in zones where certain metals had high concentration were detected. These parasites can be used as indicators of pollution in the study area. KEYWORDS : Physicochemical, detected, pollution, concentration, indicator and prevalence.

Comparative Study of the Decomposition of Rhizophora racemosa and Nypa fruticans of the Great Kwa River, Cross River State, Nigeria

Comparative Study of the Decomposition of Rhizophora racemosa and Nypa fruticans of the Great Kwa River, Cross River State, Nigeria

Physico Chemical Parameters and Phytoplankton Assemblages along Spatial and Temporal Gradients in Great Kwa River, Calabar, Nigeria

Physico Chemical Parameters and Phytoplankton Assemblages along Spatial and Temporal Gradients in Great Kwa River, Calabar, Nigeria