Assessment of Soil and Earthworm (As Bio-Indicator) of Heavy Metals around the Cattle Market, Isheri, Along Lagos-Ibadan Express Road.

Heavy metal released by traffic activities on the road sides are important  sources of soil pollution in developed and developing countries for decades. Earthworms have been used as bio indicator of soil pollution (heavy metals) by many researchers over the years.  Vehicular emission is a major source of heavy metal in this site. This research work aimed at examining the level of heavy metals concentration in the soil and in the earthworm at the Isheri Cattle Market along Ibadan-Lagos Express road in Lagos State, Nigeria. The soil samples were collected at the surface and subsurface levels from different sections of the  market (upstream, downstream and around the market) Earthworms were also collected at the three different sections of the market. The concentration of heavy metals at the site is higher than that of the control site collected from Botanical garden, University of Ibadan. The heavy metals were digested using aqua regia (Conc. HNO3 and Conc. HCl in 1:3 ratios) and analyzed by atomic absorption spectrophotometer (AAS). This result showed that the concentration of heavy metals in all the sites ranged from 0.14 – 15.4mg/kg for Cr  , 0.012 – 1.072mg/kg for  Cd  while that of Ni, Cu,  Zn  and Pb are (0.025 – 4.69, 0.33-9.35;  2.42-41.0 and 0.19-15.82 mg/kg). The concentration of heavy metals in earthworm in the three major sections of the market ranged from 18.0 – 909mg/kg for Cr, 0.0014 – 0.056mg/kg for Cd, 0.32 – 1.39 mg/kg for Pb, 1.76 – 66.0mg/kg for Ni, Cu is 9.12 – 489mg/kg and Zn is 3.18 – 12.9mg/kg.  The earthworm present in the market is a good bio-indicator of heavy metals. This implies that vehicular emission and various burning activities are sources of environmental pollution which possesses a serious risk to human health and animals. There is need for a continuous research in this site  to monitor the increase in the concentration of heavy metals because of their toxic and carcinogenic effect in the environment. Key words Earthworm, Heavy metals, Bio- indicato

DISTRIBUTION AND BIOAVAILABILITY OF METALS IN GASOLINE CONTAMINATED SITES IN LAGOS, NIGERIA

Distribution of metals in soil of two gasoline contaminated sites in Lagos were studied. Total Concentrations of twenty-five elements were investigated in composite samples collected at different depths within the sites. The elements were determined by ICP-AES after microwave assisted acid digestion of the samples. Chemical fractionation, mobility and potential bioavailability of some of the toxic and EU priority metals e.g., Pb, Cu, Cd, and Fe were evaluated in the topsoil (0-15 cm) by sequential extraction. There were great variation in the concentrations of the elements in both sites with depth. Speciation analysis showed that Pb and Cd dominated the Fe-Mn oxide fraction while the concentrations of Fe and Cu were higher in the residual fraction in site A. In site B, Pb, Cu and Cd was mainly associated with the Fe-Mn oxide fraction, while Fe was in the residual fraction. Cd has the highest mobility factors, 33.2% (site A) and 29.5% (site B), respectively. The concentrations of most of the toxic heavy metals (e.g., Pb, Zn, Cu, Cr, Cd etc.) exceed that of the control samples and heavy metal baseline values around the world. Thus, proper management of these potentially contaminated sites is imperative to prevent human health risk

The Effects of Thermal and Cold Therapies on the Flexibility of Hamstring Muscle: A Comparative Study

Background/Objectives: There have been several reports on the severity of hamstring tightness and its consequences both in sports - related injuries as well as in pathological conditions particularly low back pain. The relative effects of the application of heating and cooling modalities on the muscles prior to the performance of flexibility exercises have not been extensively studied. This study was therefore designed to determine and compare the effects of thermal (heat) and cold (ice) therapies on the flexibility of the hamstring muscle group (HMG). Methodology: Forty-three (43) apparently healthy individuals who presented with hamstring muscle tightness participated in this study. They were randomly assigned into three groups: Heat, cold and control groups. Active knee extension lag (hamstring muscle tightness) was measured for all the participants before and after intervention using active knee extension test (AKET). All the participants were placed on static stretch exercises for 5 - consecutive days and in addition, the participants in the heat and cold groups received heat and cold therapies respectively on the HMG. Results: The results showed that there was no significant difference in the flexibility of the HMG between the participants in the cold and control groups (p > 0.05), however there was a significant difference in the flexibility of the HMG between the participants in the heat and cold groups (Right leg - t = 5.39, p = 0.02; Left leg - t = 5.41, p = 0.04)). Conclusion: It was concluded that hamstring muscle flexibility may be better enhanced by the application of superficial heat to the hamstring muscle group prior to the performance of flexibility (stretching) exercises. Keywords: Hamstring Tightness, Thermal Therapy, Cold Therapy, Stretching Exercises. Nigerian Journal of Health and Biomedical Sciences Vol. 6 (2) 2007: pp. 39-4

Process parametric optimization of spark plasma sintered Ni–Cr–ZrO2 composites using response surface methodology (RSM)

Materials properties are highly dependent on the processing parameters and technique used during sintering. The effect of Spark Plasma sintering process parameters (pressure and temperature) on the hardness and relative density of Ni–20Cr–5ZrO2 composite was investigated. Response Surface Methodology (RSM) from the design of experiment (DOE) technique was successfully employed for the experimental design, and statistical analysis was conducted on the obtained experimental results. The microstructural analysis of the sintered composite showed the presence of solid solution phases of Ni and Cr, which were confirmed by the XRD results as (Cr,Ni) alongside unreacted ZrO2 particles at sintering temperatures of 950 °C and 1000 °C. The validity of the model developed with the impact of each variable and their corresponding interaction on the responses was performed using analysis of variance (ANOVA). The relative density and hardness were the two responses considered. The actual values (experiment data) and expected values (simulated data) were subjected to statistical analysis, to develop a predictive model that synchronizes density and hardness as distinct process parameters, with material hardness and relative density serving as the responses of the specified experiment. For the responses, quantitative models were created, and 10 experimental runs were processed to ascertain the desirability of the responses. The SPS processing parameters considered the most desirable were 1000 °C sintering temperature and 50 MPa pressure. The hardness property obtained under this condition is 433.23 HV with a relative density of 98.15%