CEMENT PRODUCTION IMPACTS ON FOREST ECOSYSTEM AND RURAL LIVELIHOOD: CASE STUDY OF LAFRAGE AND OBAJANA CEMENT FACTORIES, NIGERIA

Abstract

This study evaluated the impacts of cement production on forest ecosystem and rural livelihood in Lafrage (Ogun State) and Obajana (Kogi State) cement factories. These were achieved by assessing the effects of cement dusts on forest ecosystem, physicochemical characteristics of water and soils; and rural livelihoods of the immediate communities. Data were collected from the forest ecosystem that was between 50 m and 3 km away from the cement factories. Twenty plots of 25 x 25m were centrally located at interval of 10m. In each plot, tree growth variables (Dbh, total height, diameter at the base, middle and top) were measured. Samples of plants parts (barks and leaves) were collected for the determination of their chemical constituents. The dust load of 40 leaves (five leaves from different eight predominant tree species) was also estimated. Soil samples were collected from each plot at the topsoil (0-15cm) and bulked for physical and chemical laboratory analyses. A simulated soil-cement mixture was adopted for microscopic characterization of fungi and bacteria. Water samples from a River and a well around the cement factories were collected for analyses. Water pH, conductivity, temperature and total dissolved solids were determined in-situ while dissolved oxygen and ammonia were determined in the laboratory. Questionnaires were administered on 50 randomly selected respondents from the communities around the factories. The results of tree species diversity and abundance at Obajana reveals a total of 204 stems/ha in 23 species and 13 families while at Lafrage, a total of 194 stems/ha in 5 species and 5 families were recorded. While there was no large diameter tree (dbh ≥ 40 cm) in the forest of any of the two sites, the adjoining forest had. The biodiversity indices are higher for adjoining forest of the two sites. The results of the analytical assessment of tree parts reveals varying values with distances away from cement factories that significantly differ from those not nearby to the factories. The results of the major chemical compositions indicated that sodium (Na) (27.44±8.14 ppm), potassium (K) (33.99±8.37 ppm) and magnesium (Mg) (0.52±0.22 ppm) of Daniellia oliveri leaf samples in proximity to the factories were lower compared to those that are far away. The chemical compositions of the leaf samples of Terminalia avecenoide from the study area Na (24.95±6.92 ppm), P (45.30±9.53 mg/kg) and K (32.40±3.33 ppm) were also lower than those far away. For Lonchocarpus sericeus leaf samples from Lafrage, higher mean concentrations values of phosphorus (80.97±21.72 mg/kg), carbon (5.50±7.15 %), calcium (0.98±0.54 ppm), magnesium (0.81±0.22 ppm), Manganese (0.36±0.21 %) and iron (1.27±0.39 %) were obtained from nearby samples than the far away samples. At Lafrage, the Albizia lebbeck and Ficus exasperata records dust load deposition of 0.302 and 0.009 mg/cm2. Vitellaria paradoxa at Obajana had the highest dust holding capacity of 0.1035 mg/cm2. The textural characteristics of topsoil samples were predominantly sandy-loam-clay. The pH values of the topsoil samples were acidic and there were significant differences between the pH of the soil samples that were nearby to the factories and those far away. At Obajana, all the chemical elements (Na, 14.11±6.77 cMol/kg), (K, 30.76±9.89 cMol/kg), (Mg, 0.70±0.34 cMol/kg), (Ca, 1.93±0.68 cMol/kg), (N, 0.52±0.07 %), (Organic carbon, 2.99±0.90 %), (Organic matter, 5.16±1.56 %) and (CEC, 28.39±0.26 cMol/kg) obtained from samples nearby to the factories were higher than the samples far away. At Lafrage, (Mg, 1.15±0.43 cMol/kg), (Ca, 3.40±1.19 cMol/kg), and (P, 98.14±0.48 mg/kg) had higher values than the location away from the sites. The abundance of soil bacteria (1. 2 x 104 cfu/g) and fungi (7 x 103) was significantly affected on the soil containing 15g and 10g soil-cement, for bacteria and fungi respectively. For the results of water quality, the samples nearby to the factories had the highest physical and chemical properties. The cement dust has impact on the socio-economic characteristics and health of the neighbouring community dwellers as revealed by the majority of the respondents (96 % and 81 %) from the two study areas respectively. The study therefore reveals that cement industries have negative impacts on forest ecosystem, environmental, social and health of adjoining communities. So, the process of development of cement factories should be integrated with the needs of the environment.