Department of Chemistry

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Start date: 2016End date: 2018

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    Natural and anthropogenic biomarkers in recent dated sediment cores from Refome Lake, SE Nigeria: environmental implications
    (Environ Earth Sci, 2016) Oyo-Ita, Orok Esu; Oyo-Ita, Inyang Okon; Sam, Edidiong Sunday; Ikip, Ekpo Offem; Ugim, Ugim Samuel
    Natural and anthropogenic biomarkers characteristics of two recent sediment cores collected toward the shoreline and center of Refome Lake (RS and RC; 30 cm long), southeastern Nigeria, were investigated in order to reconstruct past environmental conditions and asses humans-induced changes on the local ecosystem over the last century. Results from sediment bulk properties such as total organic carbon (TOC; 0.12–0.54%; mean— 0.26 ± 0.9%), total nitrogen (TN; 0.01–0.05%; mean— 0.03 ± 0.7%) and total inorganic carbon (TIC; 0.03–0.37%; mean—0.14 ± 1.0%) contents as well as TOC/TN (5–25; mean—11.55 ± 1.4) suggested slightly higher contribution from allochthonous over autochthonous organic matter (OM), lowered by low primary production and the characteristic Niger Delta sheltered basin morphology predominated by sandy lithology. Evaluation of molecular proxies such as carbon preference index (CPI(C24–C35); 1.23–1.74: mean—1.58 ± 0.4), carbon maxima (Cmax—17, 19, 26, 27, 29), long-chain/short-chain hydrocarbons (LHC/SH-C; 0.77–2.25, mean—1.52 ± 0.3) and Paq, (0.21–0.61, mean–0.45 ± 0.3) as well as C29/C27 (0.89–2.67; mean—1.53 ± 0.2) indicated an admixture slightly predominated by microbial OM (algae/bacteria) in the most recent top layer (RC1, 0–5 cm) of RC core and slightly more enhanced terrestrially derived OM in the middle layer (RS4, 15–20 cm) of RS core. The later sediment layer deposited at ca. 1947–1964 coincided with the period of greater wash-in of land-derived OM (associated with tree logging/forest clearing for foot path extension and farmland preparation authorized by the European settlers) occasioned by intense rainfall. The occurrence of gammacerane and 18a-oleanane in low levels in the lower and upper layers revealed trace contamination by petroleum hydrocarbons imported into the Nigerian economy prior to independence in 1960 and utilization of Niger Delta oil after 1960 following departure of the colonial masters (the British), respectively.
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    Source Characterization and Historical Trend of Sedimentary PAHs from Refome Lake, South–South Nigeria
    (Aquat Geochem, 2017) Oyo-Ita, Inyang O.; Oyo-Ita, Orok E.; Ikip, Ekpo O.; Sam, Edidiong S.; Ugim, Ugim S.
    Polycyclic aromatic hydrocarbons (PAHs) released from diverse sources passing through water column carry information into the sediment where they can be used to assess the environmental status of an ecosystem over specified geologic time frame. The vertical distributions of PAHs in two recent sediment cores (RS and RC, 30 cm long) from Refome Lake, South–South Nigeria,were investigated using gas chromatography–mass spectrometry in order to evaluate their sources and historical trends of deposition over the last ca. century. The total PAHs (TPAHs—sum of parent and retene) concentrations ranged from 66.99 ng/g dry weight (dw) at the middle layer ofRCcore (RC3 10–15 cm) to 182.24 ng/gdwat the near-bottomlayer of RS core (RS5 20–25 cm) with amean of 102.21 ± 24.32 ng/g. The elevated TPAH level at the near-bottom layer of the RS core, corresponding to geologic time-frame ca. 1930–1947, coincided with the period of inhabitation of the European settlers along the lake’s catchments when utilization of coal and/or coal products for domestic/recreational activity was at its peak. A decline in TPAH levels up-cores thereafter reflected the periods of gradual evacuation of inhabitants of the lake area hinterland following the departure of theWhite after the Nigerian independence in 1960. Evaluation of PAH category according to ring size coupled with data from specific molecular ratios revealed inputs dominated by wood/coal combustion with a moderate contribution from petrochemical/liquid fossil fuel exhaust emissions and a minor diagenetic sources. Principal component analysis result not only distinctively separated RS fromRCcore samples but also revealed that the RS samples weremore impacted by wood/coal combustion emissions than the RC, while liquid fossil fuel exhaust emission dominated the RC over the RS samples. Although short-range eolian transport did play a role in the delivery of PAHs to the lake, localization of source contamination was more important.
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    Determination Of Nutritional Potential Of Cymbopogon Citratus (D.C.) Staph By Atomic Absorption Spectroscopy And Its Health Benefits
    (International Journal of Innovative Research and Advanced Studies (IJIRAS) Volume 5 Issue 3,, 2018) Umoh, Emmanuel Michael; Sam, Edidiong Sunday; Udoh, I. I.
    Lemon grass (Cymbopogon citratus) was processed for analyses. They were sorted and chopped into bits. They were sundried for 12hrs, oven dried for 24hrs at 60oC and pulverized. Digestion was carried out according to AOAC 2000 and analysed for P, Mg, K, Na, Se, B, Co, Fe, Zn, Mn, Cu and Ca contents using Unicam 939/959 Atomic Absorption Spectrophotometer. Out of these twelve “botanical based minerals”, the most abundant was potassium followed by magnesium, phosphorus and calcium the least being boron. Most nutritional problems in Nigeria experienced by the vulnerable groups - the children and the elderly are due to mineral deficiencies in unwholesome or processed foods. Minerals usually obtained from synthetic mineral supplements are inadequate for the rural population due to high cost of procurement and at times adulteration. Most of them are toxic to susceptible individuals. Lemon grass is very effective in „Ajurvedic‟ medicine because of the “botanical based minerals” and bioactive compounds therefore taken in adequate quantities will help in the improvement of general health.