Gravel road dust has significant health effect. The study was conducted to assess road dust suppression effect of molasses stillage in gravel at a Sugarcane Estate in Zimbabwe. Three, 2 km long gravel road sections (steep, sloping and gentle) had the following dust suppression treatments applied to 500m long segments: (i) molasses stillage, (ii) water and (iii) control. Data on dust deposition rates were subjected to Analysis of Variance (ANOVA) to compare treatment means. Mean road dust deposition rates ranged from 998.46±50.04 to 6184.02±257 mg/m 2 /30 days between January and June 2012. Road segments treated with molasses stillage had the lowest (P = .05) dust deposition rates compared to other treatments. Dust deposition rates were reduced by 77-83% and by 18-39% for molasses stillage and water treatments respectively. The sloping road segments had consistently the highest (P=.05) mean dust deposition rates. It was concluded that molasses stillage outperformed water as a road dust suppressant but variations were caused by type and volume of vehicular traffic together with meteorological factors at the Estate.

Long-lived natural radionuclides such as ( 238 U) uranium-238, ( 232 Th) thorium-232, ( 226 Ra) radium-226 and ( 40 K) potassium-40 and heavy metals are normally exposed to the surface during mining activities. They enter the human body when inhaled (as dust) or ingested (by drinking contaminated water). An intake of large concentrations of these radionuclides and heavy metals can lead to health effects such as development of cancers. The aim of this work was to assess the radiological health risk due to intake of radionuclides in dust and drinking water from the West Rand gold mining area and Modiri Molema Municipality (MMM) water treatment plant. The dust samples were analyzed for radionuclides of interest using the well-type high purity Germanium detector. Water samples were collected before and after purification from the Modiri Molema Municipality water treatment plant and analyzed using the ultra-low level Liquid Scintillation Counter (LSC), to evaluate the gross alpha and beta radioactivity dose levels of the radionuclides in water. An Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to evaluate the heavy metal concentrations in the drinking water after purification at the treatment plant. The total inhalation effective dose obtained in this study was (2.71 Â 10 À1 and 1.31 Â 10 À1 ) μSv.y À1 for adults and infants respectively, which is below the prescribed dose range of 5-10 μSv.y À1 . The mean activity concentrations of the radionuclides in air dust were found to be; 226 Ra, (2.14 AE 0.82) Â 10 À6 (Bq.m À3 ), 238 U (6.08 AE 2.17) Â 10 À7 (Bq.m À3 ) and 232 Th (2.65 AE 1.1) Â 10 À7 (Bq.m À3 ). The activity concentration of 226 Ra obtained exceeded the world average by 2 times. The Ra eq , the external hazard (H ex ) and internal hazard (H in ) indices were calculated and the values obtained from soil were lower than the world average. However, the absorbed dose rate in air was higher than the world averages of 60 nGyh -1 . The minimum and maximum gross alpha activity obtained was 0.0041 (Bq.L À1 ) and 0.0053 (Bq.L À1 ) respectively, while the minimum and maximum gross beta activity obtained for water samples was 0.0083 (Bq.L À1 ) and 0.0105 (Bq.L À1 ) respectively. More heavy metals were detected in the first two stages of the water treatment than on the last two stages, nevertheless, their concentrations did not exceed recommended limits. The results for soil dust indicates that the windward areas might pose health risks for human population staying in the area and the activity concentration for drinking water indicate that the specific activity in the water supply after purification is below the WHO guideline limit of 0.5 (Bq.L À1 ) for gross alpha and 1 (Bq.L À1 ) for gross beta. The results obtained were also within the range of the South Africa Department of Water Affairs and Forestry target water quality limit of (0-1.38) (Bq.L À1 ) for gross beta activity. Heavy metals concentrations in drinking water did not exceed the stipulated limits by USEPA and DWAF. Therefore, this water after...

Windblown dust can contain radioactive materials from mining. These radionuclides when inhaled in dust produce ionizing radiation which damages the cells and tissues in the body. The aim of this study was to assess dust fallout radionuclides in the West Rand mining area of South Africa. Dust fallout monitoring was done using the method (ASTM) D-1739 of 1998 employing multi-directional buckets. Results show that all 9 locations investigated in the different seasons recorded dust fallout rates within stipulated residential limit according to the National Dust Control Regulations (NDCR) (Government Gazette 36974, 1 Nov 2013). Locations 3 in spring (301.93 mg/ m 2 /day) and 6 in winter (589.8 mg/m 2 /day) recorded dust fallout rates with values above the target value of 300 mg/m 2 /day according to guidelines by South African Standards (SANS 1929:2011). The ANOVA tests (p-value < 0.05) indicate that the mean dust fallout rate is significantly different across the seasons, mean dust fallout rate in summer is significantly (p-value < 0.05) more than the autumn by 103.15 mg/m 2 /day. Moderate, positive correlations (0.4 ≤ r < 0.7) exist between average dust fallout rate and wind speed. A weak, negative correlation exist between average dust fallout rate and rainfall with a value of-0.393. All the investigated elements had Enrichment Factor (EF) greater than 1. Cadmium (Cd) and lead (Pb) were extremely enriched (68.36 and 43.48, respectively), whereas Thorium (Th) (7.26) and Chromium (Cr) (9.79) had significant enrichment. Activity concentrations obtained for 226

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