Although, many heavy metals are necessary in small amounts for the normal development of the biological cycles, most of them become toxic at high concentrations. The major sources of heavy metal pollution in urban areas of Nigeria are anthropogenic, while contamination from natural sources predominates in the rural areas. The study examined heavy metal status of boreholes in Calabar South, Cross River of Nigeria. Four functional boreholes in the area were sampled. Result showed that the concentrations of iron (Fe), zinc (Zn) and Manganese (Mn) were within WHO maximum permissible limit with mean values of 0.065ml-1 g, 0.015mgl-1 and 0.002mgl-1 respectively. The proportion of copper (Cu), chromium (Cr) and lead (Pb) in the sampled boreholes was zero, indicating the absence of these metals in the sampled boreholes. The absolutely low levels of heavy metal contents across the sampled boreholes showed they were not polluted and as such suitable for human consumption. The low content also revealed that boreholes in the area were located far away from dumpsites; soak away pits, automobile shops and other forms of heavy metal contaminants. In order to maintain quality status of boreholes in the area, routine monitoring and assessment of boreholes mostly the indiscriminate sinking of boreholes in the area by sanitary inspection officers was suggested.

Identifying ecological variables that explain significant variation in the stock of carbon is indeed one way of sustaining its concentration in the soil. The stepwise multiple regression model was employed to identify ecological variables that explained significant variation of carbon in fallow soils. Using fallow genealogical cycles of 1 st , 2 nd , 3 rd , 4 th and 5 th generations, soil and vegetation variables from 30 sampling plots were collected and subjected to linear regression analysis. The analysis generated three predictive models. The first and second models significantly (p<0.01) explained 78% (R 2 = 0.78) and 87% (R 2 = 0.87) of the variability in soil organic carbon (SOC), while the third (full) model significantly (p<0.01) explained 89% in the variability of carbon stock (R 2 = 0.89) with vegetation cover, available phosphorus and total nitrogen being the most significant predictor variables. The full model was upheld because it identified three significant ecological variables that explained increased variability in the stock of SOC. The study suggested that management of the ecological variables identified in the full model which indeed were associated with the abundance of woody and herbaceous vegetation would not only increase the stock of SOC in the soil, but reduced its concentration in the atmosphere. For this to be feasible mostly in the present changing climate, healthy forest and land management practices, such as the creation of vegetal buffer zones around farmlands, zero-tillage practice, mulching, retaining of forest slash and crop residues, fertilizer application, elongation of fallow periods, and tree planting initiatives in degraded ecosystems were encouraged.

The study examined the effect of fallow generational cycles on the buildup of nutrients in the soil. Fallow sequence of 1 st , 2 nd , 3 rd , 4 th and 5 th generations were studied. The quadrat approach of sampling was employed to collect soil samples (surface and subsurface) from five plots of 10m x 10m across the five fallow generational cycles. Result showed that the mean proportions of organic matter (OM), total nitrogen (TN), cation exchange capacity (CEC) and available phosphorus (Av. P) increased substantially in the 1 st and 2 nd generation of fallows probably due to reduced cropping frequency. The PCA result further revealed that topsoil available phosphorus, topsoil exchangeable sodium and topsoil exchangeable potassium constituted the most significant soil properties that progressively increased across the fallow generations. As usual, nutrients in the fallow generations were confined to the topsoil. The increase in soil nutrients was attributed to the increased in tree size, vegetation cover and adequate ground cover which helped to conserve and build-up essential nutrients in the soil by minimizing the loss of nutrients through soil erosion. The study suggested that for efficient conservation practices, fallow land mostly the 1 st generation fallow which was fast approaching climax should be considered for reserve. For this to be feasible, alternative means of livelihoods should be provided to reduce the wanton destruction, concentration and dependence on forest resources for sustenance.

Background: The disease Tuberculosis (TB) is a contagious illness which is rampant in Nigeria.

The study evaluated the influence of vegetation characteristics on nutrient loss in vegetation fallows in a part of the rainforest belt in Agoi-Ekpo, Cross River State. Participatory method was used to identify fallows of 3-year and abandoned farmland. In each identified fallow category, 10 plots for vegetation estimation was established, while two runoff plots of 10m x 4m was constructed and used for nutrient loss estimation. Data was gathered during the cropping season of March to November, 2012. Results showed that on the 3-year fallow only basal cover was retained by the model and significantly explained Ca loss (R 2 = 0.627, F = 3.655, p<0.01), Mg loss (R 2 = 0.57.2, F = 3.271, p<0.05) and potassium loss (R 2 =0.527, F = 2.980, p<0.05). On the abandoned farmland, the model retained only crown cover and it significantly explained OC loss (R 2 = 0.591, F = 3.402, p<0.01), TN (R 2 = 0.599, F = 3.456, p<0.01), Ca (R 2 = 0.674, F = 4.067, p<0.01), Mg (R 2 = 0.796, F = 5.75, p<0.01) and K (R 2 = 0.823, F = 6.090, p<0.01). The study showed that more nutrient element losses were recorded in the abandoned farmland. The study suggests that trees and shrubs should not be completely cut down on farmlands facilitate rapid vegetation restoration during land abandonment.