An Application of Multivariate Techniques in Plankton Study of a Freshwater Body in the Niger Delta

We utilized the principal components analysis (PCA) and hierarchical cluster analysis (HCA) to organize and interpret numerical abundances of phyto- and zoo-plankton biotypes of the middle course of the Imo River in a southeastern locality in Nigeria. PCA was used for data reduction while HCA was used to reveal natural groupings within data set of numerical abundances. Phytoplankton taxa abundance was dominated by bacillariophyceae (diatoms) (53.25%), while zooplankton was dominated by Cladocera (25.87%). Two plankton taxa PCs which accounted for about 76.30% variability in original 14 variables correlated most with Rotifera and fish eggs and larvae. HCA revealed chrysophyceans, euglenophyceans, cyanophyceans and chlorophyceans, as well as Crab larvae, fish eggs and larvae, beetle larvae and Copepoda forming the first and richest phytoplankton and zooplankton clusters, respectively. Results reveal that both extraction and clustering outputs utilized underlying criteria (such as seasonality and climatic variability) rather than numerical abundances in their classifications. Keywords: Plankton taxa, PCA, HCA, multivariate analysis, numerical abundanc

ATTENUATION OF HEAVY METALS IN SEDIMENTS OF THE BONNY ESTUARY, NIGERIA: THE ROLE OF OXYGEN

Sediments of the Bonny Estuary, which is repository to pollutants from various industrial and shipment activities in its catchment was investigated for rate of natural attenuation of toxic metals (Cd, Mn, Cr, Pb, Cu, Ni, Fe) under aerobic and anaerobic conditions. Samples were collected with pre-grab sampler from seabed, sieved in the laboratory and monitored under aerobic and anaerobic conditions. After incubation at 18°C, harvests were made on days 1, 14, 28 and 42 and levels of the metals determined spectrophotometrically. Variation plots, ANOVA, Means plots, Student’s t-test and Pearson correlation (r) were used to analyze data. Concentration reductions were higher in aerobic condition in the order Cu(15.5%)> Cd(11.4%)> Fe(8.0%)>Mn(5.7%)> Cr(4.4%)> Ni(4.2%)>Pb(3.9%) than in anaerobic condition which was in the order Cu(7.5%)> Cd(7.4%)>Pb(2.4%)>Mn/Cr(1.8% each)> Fe(0.9%)> Ni(0.5%). There was significant heterogeneity in metals reductions (Sig. F=0.000) on all the harvest days, especially of Cu, Pb and Fe at P<0.05. Attenuation of Mn also differed markedly between the aerobic and anaerobic conditions (Sig. t=0.005) at the 95% confidence interval. pH influenced the attenuation of Ni (r=0.766) and Fe (r=0.795) (P<0.05) as well as Cd (r=0.968), Cr (r=0.861), Pb (r=0.989) and Cu (r=0.950) (P<0.01). Results indicate that rate of attenuation was slow and slightly enhanced by oxygenation

Contributions to the environment of priority Polynuclear Aromatic Hydrocarbons from the Coal Camp Mechanic Village (CCMV) in Enugu, Nigeria

ABSTRACT The Coal Camp Mechanic Village(CCMV) in Enugu,Nigeria generates automobile oily wastes which could contain the Polynuclear Aromatic Hydrocarbons (PAHs) and distribute them to the proximal segments of the environment. The current study investigated the presence and levels of the PAHs in soils of the CCMV, as well as in water and sediments of the nearby Okpete Stream. Samples were collected using standard methods and PAHs detected with a Gas Chromatograph interfaced with Flame Ionization Detector. Mean concentrations of the PAHs [except 1,2-Benzanthracene and Benzo(k) fluoranthene] exceeded the World Health Organization's permissible limit of 0.2µg/L for drinking water. Two Principal Components (PCs) formed the extraction solution, with a cumulative percentage variability contribution of 96.6% in the original 16 variables; with PC 1 most highly correlated with Fluorene/1,2,5,6-Dibenzanthracene (0.979) and PC 2 with Acenaphthene (0.982). There was significant spatial heterogeneity in mean levels of the PAHs in water samples (Sig. F=0.013) at P<0.05, and Indeno (1,2,3-cd) pyrene (16.13429 µg/L) and Fluoranthene (92.30784 µg/L) contributed the difference most. Results raise public health alert as PAHs are known carcinogens. Recycling of waste/used oils is recommended for environmental sustainability

Correlates in Groundwater Quality Parameters and Textural Classes of Soils in a Peri-industrial District of the Nigerian Delta Region

This study investigated the physicochemical status of groundwaters of the oil-rich Ekakpamre community in Ughelli, Nigeria. Ten borehole water samples located about 1 km apart and soil samples around them were collected and analyzed by standard methods. Clay, sand and silt compositions in overlaying soils appeared to influence the DO (r=-0.999), TPH & toluene (r=0.998, each), and K+ ion (r=-0.999) levels in groundwaters at P<0.05. Three PCs which accounted for 100% variability in the original 27 variables formed the extraction solution and were most correlated with Cr (0.995), Pb (0.989) and PO42- ions (0.947). Though the high compositions of clay (72.67 ± 2.33%) and low compositions of sand (24.33 ± 2.60%) in the study indicates slight possibility of migration of surface pollutants to aquifers, the exceedances of Pb and Cd levels over regulatory limits portends public health hazards to consumers of groundwaters in the area. Keywords: Physiochemical status, Groundwater, Peri-industrial District, Niger Delta, Water contamination,    Textural compositions 

Accumulation and recovery capacity of heavy metals in sand mine ponds of the Otamiri River in Owerri, Nigeria

This study investigated the levels, index of accumulation and recovery capacity of heavy metals (Pb, Cd, Cu, Ni, Zn, Fe, Mn) in sand mine ponds of the Otamiri River in Owerri, Nigeria during the wet season of 2012. Water (WC) and sediment samples (SD) were collected from six sampling points, with WC 1-WC 3 and SD 1-SD 3 located within a derelict mine pond and WC 4-WC 6 and SD 4-SD 6 located within an actively mined pond. The pH was determined in situ and levels of heavy metals measured with the atomic absorption spectrophotometer. The student's t-test, index of geoaccumulation (Igeo), accumulation factor (AF) and pond recovery capacity (PRC) were computed for the ponds. There was significant spatial heterogeneity in mean levels of the heavy metals in sediments (sig. t=0.029) at P<0.05, with higher levels of metals also recorded in sediments than water columns. The order of Igeo was Fe (5.959) &gt; Zn (4.932)&gt; Cu (4.743) &gt; Mn (4.326) &gt; Pb (3.214) &gt; Ni (2.483) &gt; Cd (1.649), AF was Zn (1.513) &gt; Cd (1.179) &gt; Fe (1.082) &gt; Ni (1.048) &gt; Mn (1.042) &gt; Cu (1.032) &gt; Pb (0.987) and PRC was Zn (33.891) &gt; Cd (15.165) &gt; Fe (7.604) &gt; Ni (4.608) &gt; Mn (4.047) &gt; Cu (3.052) &gt; Pb (-1.373). Active mining led to extreme contamination of the ponds with Fe, strong to extreme contaminations with Cu, Zn and Mn, strong contamination with Pb, moderate to strong contamination with Ni and moderate contamination with Cd. However, Pb showed deficit recovery capacity and this could portend unfavourable ecological consequences on resident biota and raises public health concerns among resource dependants of the river. Strict enforcement of regulations on in-stream sand mining should be applied

APPLICATION OF BIOFILMS IN REMOVAL OF HEAVY METALS FROM WASTEWATER IN STATIC CONDITION

The aim of the research was to utilize biofilms as a model in ecotoxicology to remove selected heavy metals (Cd, Cu, Cr, Zn and Pb) from wastewater in a static condition. Biofilms were grown in three graded concentrations of the metal leachates (0.625, 0.417 and 0.250 %), harvested after 1, 2 and 3 weeks and analyzed for heavy metals. Mean accumulations peaked on Day 21, and of Cd ranged from 0.000 to 0.040 (mean = 0.00837 ± 0.002), Cu from 0.000 to 0.212 (meam = 0.03929 ± 0.012), Cr from 0.000 to 0.500 (mean = 0.05821 ± 0.021), Zn from 0.000 to 1.456 (mean = 0.31833 ± 0.109) and Pb from 0.000 to 0.099 (mean = 0.02129 ± 0.006) mg/g in resultant biofilm formations. Accumulation of the metals increased significantly with time [F(205.59) > Fcrit(3.95)] at the 95% confidence interval. Those of Pb was significantly higher in the 0.625% leachate mixture than control (Sig F = 0.034) at P < 0.05, even as those of Cd and Cu were slightly higher in the concentrations than control. Biofilm model removed small amounts of metals from wastewater stream in static condition