Preliminary Investigation of Trace Elements Concentration in Dust from Tin Processing Mills in Jos - Bukuru Area, Northcentral Nigeria

The Jos – Bukuru Biotite Granite is the largest of the biotite granite belonging to the Younger Granite province of Nigeria. The rock hosts the tin and columbite mineral which on weathering released them forming the alluvial deposits mostly along stream channels. These minerals were extensively mined in the early 19th century and remained active until late 1970s. Mining and processing of these minerals is still ongoing but on smaller scales around the Jos – Bukuru area. The aim of this work was to determine the concentration of trace element in dust generated during milling and processing of Tin and associated minerals. Fifteen dust samples were collected during the air floating and after floatation operations in nine different processing sites by placing filter papers at designated locations. Dust samples were analysed by Inductively Coupled Plasma Optical Emission Spectrometry. Generally, in all the processing mills Pb, Zn, Th, U are quite high. Pb ranges from 204.5 – 1177, Zn, 67.0 – 1,272, Th > 200 in all samples, U, 186.5 – 1623, As, 0.3 – 233.7 ppm respectively. Anthropogenic factor and index of geo-accumulation calculated for some of the trace elements indicate that the contamination level of trace elements ranges from uncontaminated (Ni), Uncontaminated to moderately contaminated (V, Co, Fe, Cr, Ti), contaminated to highly contaminated (Cu Se, Pb, U, Th, Zn, As and Mo). The use of mask to cover the nose and other protective clothing for other parts of the body during floating operations is not practiced, hence inhalation of this dust by workers posses a great risk to health. Keywords: Younger Granites, Columbite, Tin, Dust, Anthropogenic, Geo-accumulation, contaminate

Seasonal variation in fluoride content in groundwaters of Langtang area, Northcentral Nigeria

Thirty groundwater samples were collected at the peak of the rainy season and analysed for fluoride and other cations and anions in drinking water sources of Langtang area. For comparative purposes, thirty seven groundwater samples were collected in the dry season. The aim of the study was to determine variation in fluoride content with respect to the seasons. Fluoride in water was determined by the Ion Selective Electrode (ISE) and the cations by the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The anion (sulphate) was determined by Multi – Ion Colorimeter, bicarbonate and chloride by titration method. In addition fluorine content in aquifer materials from a borehole section were determined by Fusion method. The two seasons show variation in content of fluoride in groundwater. Fluoride content in groundwater is higher in the dry season ranging from 0.13 – 10.3 mg/ l compared to the 0.06 – 4.60 mg/l values in the rainy season. Content of fluorine (0.01 wt %) in the aquifer materials (sands) is low from depth of 0 to 7.95 m. However, fluorine content increases with depth, from 7.95 to 10.60 m with concentration of 0.04 wt %, 0.05 wt % from 10.60 to 13.25m, and 0.07 wt % from 13.25 to 15.70 m, the content of fluorine however, decreased at depth 15.70 to18.55m with concentration of 0.02 wt % even with fluorite mineral in the aquifer material at this depth. Dilution of fluoride ion as a result of rain input which recharges the aquifer may be the main reason for lower values recorded in the rainy season. Over fifty and sixty percent of waters in both dry and rainy season have fluoride concentration above the WHO upper limit of 1.5 mg/l. Consumption of these elevated values of fluoride in groundwater of the study area, clearly manifests as symptoms of dental fluorosis