Assessment of heavy metal concentration in water around the proposed Mkuju River Uranium Project in Tanzania

Effective verification for compliance with water quality standards in uranium mining in Tanzania requires data sensitive to monitor heavy metal concentration in water around the Mkuju River Uranium Project before mining commences. The area susceptible for pollution by the project was estimated using AERMOD dispersion model and found to cover about 1300 km2. Thirty one surface and groundwater samples were collected and analysed for heavy metals and physicochemical properties using ICP-MS and standards techniques, respectively. The physicochemical properties for water samples analysed ranges from 5.7 to 7.8 for pH, 2.8 to 80.2 mg/L for TDS and 15 to 534.5 mS/cm for EC. These values show that the water in the vicinity of the Mkuju River Uranium Project is normal. The ranges of concentration of heavy metals (μgL-1) determined in water ranges were: Al(2 to 9049), Cr(0.2 to 19.96), Mn (0.1 to 1452),Fe(2 to 53890),Co(0.02 to 27.63), Ni(0.2 to 9.7), Cu(2 to 17), Zn(2 to 62.94), As(0.4 to 19.17), Cd(0.02 to 0.14), Pb (0.02 to 78.68), Th (0.002 to 1.73),U(0.002 to 29.76). These values are below the tolerance levels of concentrations set by different International organisations. Therefore heavy metal toxicity in the study area is marginal. The parameters that could serve as baseline data because of their enhanced sensitivity to pollution were (i) concentration of chromium, cobalt, nickel, copper, zinc, arsenic, cadmium and lead in water (ii) pH, TDS and EC for water, (iii) TDS ratio for surface to ground water values and (iv) correlation coefficients between the heavy metals. However, since TDS values are season dependent, this indicator can serve as baseline data when measured during the dry season as was the case in the study.Keywords: Baseline, Heavy Metal Pollution, Mkuju River Project, Uranium Mining, Water Pollutio

A water curtain-based wayside protection system for tunnel fire safety

Tunnel fire safety plays a key role in the railway operations and many procedural and technological improvements have been realized in order to prevent and mitigate the fire risk. The fire prevention and protection procedures can be approached through two main different strategies: the deterministic/ prescriptive based approach and the performance-based approach. In the study presented in this paper, the possibility of application of the water curtain-based wayside fire protection system, as one of the auxiliary systems for improving and upgrading the fire safety in the railway tunnels for the smoke compartmentation, has been studied and analysed. A finite element-based dynamic simulation model has been developed in order to simulate different fire scenarios and to assess the water curtain-based fire protection system performances in terms of efficiency against the toxic smokes and gases propagation into the railway tunnel. Some preliminary numerical results have been presente

The influence of gold mining on radioactivity of mining sites soil in Tanzania

The activity of 226Ra, 232Th and 40K in soil samples were measured by gamma spectrometry using high-purity germanium detector. The study involved 40 samples from four divisions: 10 samples each were drawn from the control area (CTR), washing area 1 (W1), washing area 2 (W2) and the mining pits (MP). Radium and Thorium were measured in highest value (80.44 and 94.62) Bq/kg, respectively at MP-9 while the lowest levels (1.56 and 0.96) Bq/kg, respectively were detected at MP-2. At W1, 40K (max. 887.5 Bq/kg) recorded the highest mean level while 232Th (mean=16.7 Bq/kg) had the lowest level. For W2, 40K (max. 1535.7 Bq/kg) recorded highest level and 232Th (mean = 8.1 Bq/kg) recorded the lowest (10.7 Bq/kg). Results further show that mean activity levels of 226Ra, 232Th and 40K fromining area 42.5, 35.5 and 652.4Bq/kg, respectively. In comparison, the respective average activity for 40K, 226Ra, and 232Th recoded 118.4, 14.5 and 9.7 Bq/kg, respectively in control area. For the sake of assessing the suitability of building materials, hazard indices were calculated and their results were less than unity indicating that, building materials are safe. The annual gonadal equivalent dose, representative gamma index, alpha index revealed values of 484.8 µSv/y, 1.1 and 0.2, respectively. The average annual effective dose was 85.5 mSv which is about 8% greater than the world average. Results show that mining activities in Rwamagasa might be posing radiological hazard to people. Therefore, measures on radioactive materials to the miners and the surrounding community are recommended

Valutazione del rischio da antiparassitari per l'operatore addetto al diserbo del riso e del mais nella regione Lombardia : risultati di una indagine pilota

This pilot study has been carried out in the region of Lombardy (Italy) with the aims of: (1) assessing pesticide exposure and risk in herbicide application in rice and maize crops and (2) testing an integrated approach, in which all the main variables related with working modalities are considered, and the levels of exposure are assessed through the determination of both external and internal dose. Nine small agricultural enterprises have been considered, 4 engaged in rice and 5 in maize cultivation, with 1 applicator/each. The study pointed out median levels of absorption of 1.02 mcg/kg/die(range: 16.04 \u2013 0.81), for propanil and 0.02 mcg/kg/die (range: 0.074 \u2013 0.009) for terbutilazine. The absorbed dose resulted largely minor than Acceptable Operator Exposure Levels (AOELs) in all the subjects considered. The levels of excretion of 3,4 dichloroaniline showed a statistically significant difference between pre exposure (Median = n.c.) and post exposure levels (Median \ue9 24.5mcg/24h), whilst no difference was observed for terbutilazine excretion. Finally, correlation between calculated internal dose and metabolite excretion was significant (Spearman\u2019s rho = 0.9, p < 0,05). In conclusion, our study suggests that, in the exposure scenario considered, the risk for the operator is negligible, Moreover, our approach might allow the definition of biological exposure indices for selected pesticides and be useful for the creation of exposure and risk profiles

Waves of infection and waves of communication: the importance of sharing in the era of Covid-19

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