THE EFFECT OF DUST EMISSION FROM CEMENT FACTORY ON METAL CONTENT OF SOIL AND CROP PARTS AND ON MORPHOLOGY AND YIELD OF SOME SELECTED CROPS NEAR CEMENT FACTORY, MEKELLE, ETHIOPIA

The purpose of this study was to investigate the effects of dust generated from a cement factory located in North-western Mekelle on the fertility of soil to support the growth of three commonly cultivated crops, namely: wheat (Triticum aestivum L.) barley (Hordeum vulgare L.) and Teff (Eragrostis tef.) with regard to morphology and yields. Three top bulky soil samples were collected from three sites at 500 (Site-1), 1000 (Site-2) and 1500 (Site-3) meters from the western side of a cement factory where the dust predominantly blows by the wind. A fourth control soil sample was collected from unaffected area at 6 km distance away from the plant. The soil samples were used for pot experiment undertaken under glasshouse conditions at Mekelle University. Morphological and yield parameters such as shoot, root and spike length and leaf area using standard scales were measured. In addition to pH, EC, major metals: Ca, K, Na, Mg, Mn, and trace elements: Cd, Zn, Cu, Pb, Ni, Cr and Fe content for soil and plant parts were determined using AAS and UV spectroscopy, respectively. The results showed that dust emission has played evident role in increasing the trace metals content in the soil and consequently on the trace metals concentration of crop parts as compared with the control site. Both clinker feed and clinker which represent the major composition of dust from cement factory showed elevated values of Pb, Cu and Cr. However, with the exception of Cr, the concentrations of the other trace metals (Pb, Cu, Zn and Mo) were higher in the soil than in the dust from the cement implying their accumulation in years. Pb and Mo ranging from 0 to 3 ppm and 8 to 11 ppm respectively showed increment in wheat seed grown in Site-1 up to Site-3 compared to control site. In the seeds and body parts of barley and Teff crops, Zn and Cu showed a decreasing trend with distance. The water soluble Cu, Mn and Cr portions also showed higher values in clinker feed, clinker and soil in Site-1 as compared to the other metals. Barley and Teff had better shoot length growth and seed count in the Site-1 and Site-2 indicating the possibility of positive role of dust to crop growth and yield. Most significant correlations among the chemical and morphological parameters were found in wheat than in barley and Teff. Therefore, the dust emitted from Cement Factory resulted in increased trace metals content of cereals grown near the cement plant.