Estimation of lead in urine of school children in south western Nigeria and effect of ascorbic intervention

This study was carried out to investigate the level of lead in the air and urine of pupils in selected schools in south western Nigeria and ascertain the effect of ascorbic acid, with a view to providing baseline data on lead levels in children. A total of 197 pupils in schools in urban and rural communities of Ife Central Local Government, Osun State in the south west of Nigeria (that is Sabo, Iremo and Ajebamidele (n = 119) and Kajola and Abagboro (n = 78), respectively), The pupils in both communities were randomised into experimental and control group, the experimental group were placed on 500 mg of ascorbic acid daily for five days. Urine samples were collected on the first, third and fifth day of the study from the pupils in experimental and control groups and analysed for lead using Atomic Absorption Spectrophotometer. Air samples were collected using the LaMotte air sampling pump and analysed for lead using the same method. The cross sectional survey indicated that the mean lead levels in the air in the school environment in the urban communities on the first, third and fifth day of the study were (8.69 ± 0.070, 9.27 ± 0.09 and 9.27 ± 0.09 ìg/m³) respectively and significantly higher than lead levels in rural communities (3.73 ± 0.030 ìg/m³). The lead concentration in the urine of the pupils in experimental group in urban (5.51 ± 1.07 ìg/m³) and rural communities (5.27 ± 0.98 ìg/m³) were similar on the first day of the study. The ingestion of ascorbic acid increased excretion of lead in the urine of pupils significantly (11.22 ± 1.48 ìg/m³) on the third day and decreased marginally on the fifth day (9.87 ± 1.20 ìg/m³) in the urban communities. Similarly in the rural communities there was a significant increase (11.52 ± 1.41 ìg/m³) in the excretion of lead in the urine of pupils on the third day but a marginal increase on the fifth day (12.88 ± 2.27 ìg/m³) of the ascorbic acid ingestion. The lead level in the air on the first day of the study had no linear relationship with urinary lead level in the urban and rural communities whilst on the third and fifth day of the study, a linear relationship was observed between lead levels in the air and urinary lead levels of the pupils in the urban and rural communities

Influence of organic wastes amendment on growth and foliar yield of jute mallow Corchorus olitorius (linn.) In South Western Nigeria

This study investigated the growth and foliar yield responses of jute mallow (Corchorus olitorius Linn.) on soils amended with ashed and unashed corn cob and coconut husk agro-waste. Slightly acidic (pH=6.20) sandy loam soil were collected and incubated for six and twelve weeks respectively for the study, with agro-wastes [coconut husk ash (CHA), coconut husk unashed (CHU), corn cob ash (CCA) and corn cob unashed (CCU)] under greenhouse conditions. A completely randomized design was adopted with three replicates. The results showed that the corn cob ash and coconut husk ash positively enhanced soil chemical properties than their unashed version. At 2 WAP, the mean plant height ranged from 2.70 ± 0.12 cm to 3.88 ± 0.12 cm; the mean total leaf count from 3.60 ± 0.05 to 4.0 ± 0.05 and mean leaf area from 0.54 ± 0.21 cm2 to 2.48 ± 0.21 cm2 and at 8 WAP, the mean stem girth ranged from 0.43 ± 0.07 cm to 1.02 ± 0.07 cm for C. olitorius planted in soils incubated for six weeks with agro-wastes. This trend increased with the age of C. olitorius and with increase in agro-waste applications in the order CCA>CHA>CHU>CCU. These growth parameters, except the plant height were of higher values in 6 weeks soil incubation than 12 weeks soil incubation. The highest mean yield (17.93g/pot) of C. olitorius was obtained in soil pots amended for 12 weeks with 5 t/ha of CHU. The increase growth and foliage yield obtained in this study showed that soils amended with ashed and unashed corn cob and coconut husk waste have the potential of promoting the production of vegetables, especially C. olitorius and also ensuring environmental sustainability.Key Words: Agro-waste, Amended soil, Coconut hust, Corn cob, Corchorus olitorius, Greenhouse, Vegetabl

Incorporating crown dimensions into stem height and basal area for Triplochiton scleroxylon

Four crown dimensions (crown diameter, crown projection area, crown length and crown ratio) were each incorporated into nonlinear individual tree total height and basal area increment models for African white wood (Triplochiton scleroxylon K. Schum). The basic height/basal area growth model was formulated as a function of the tree size (i.e. total height or basal area), age and tree form (i.e. taper which is the ratio of diameter at breast height to total height). These increment models, with and without crown dimension were fitted to a modelling data set and the statistical significance of each of the crown dimensions was examined. All the models were then compared for predictive ability using an independent validation data set. The results obtained were similar for both the total height and basal area increment models. All the crown dimensions except crown projection area were found to be significant in the basic models (i.e. models without crown dimensions) in terms of model fit. However, for predictive ability, increment models (for both total height and basal area) with crown ratio term were found to have the smallest bias and the greatest prediction precision of all the models examined both with and without crown dimension. Therefore, for tree total height and basal area prediction of African white wood, models with added crown ratio term were found to be most appropriate. Keywords: Crown dimension, growth and yield models, Triplochiton scleroxylon, African white wood Ghana Journal of Forestry Vol. 19 & 20 2006: pp. 45-5