Nnenesi Kgabi

Respiratory health effects of occupational exposure to charcoal dust in Namibia

Background: Charcoal processing activities can increase the risk of adverse respiratory outcomes. Objective: To determine dose–response relationships between occupational exposure to charcoal dust, respiratory symptoms and lung function among charcoal-processing workers in Namibia. Methods: A cross-sectional study was conducted with 307 workers from charcoal factories in Namibia. All respondents completed interviewer-administered questionnaires. Spirometry was performed, ambient and respirable dust levels were assessed in different work sections. Multiple logistic regression analysis estimated the overall effect of charcoal dust exposure on respiratory outcomes, while linear regression estimated the exposure-related effect on lung function. Workers were stratified according to cumulative dust exposure category. Results: Exposure to respirable charcoal dust levels was above occupational exposure limits in most sectors, with packing and weighing having the highest dust exposure levels (median 27.7 mg/m3, range: 0.2–33.0 for the 8-h time-weighted average). The high cumulative dust exposure category was significantly associated with usual cough (OR: 2.1; 95% CI: 1.1–4.0), usual phlegm (OR: 2.1; 95% CI: 1.1–4.1), episodes of phlegm and cough (OR: 2.8; 95% CI: 1.1–6.1), and shortness of breath. A non-statistically significant lower adjusted mean-predicted % FEV1 was observed (98.1% for male and 95.5% for female) among workers with greater exposure. Conclusions: Charcoal dust levels exceeded the US OSHA recommended limit of 3.5 mg/m3 for carbon-black-containing material and study participants presented with exposure-related adverse respiratory outcomes in a dose–response manner. Our findings suggest that the Namibian Ministry of Labour introduce stronger enforcement strategies of existing national health and safety regulations within the industry.

Composition of Inhalable Atmospheric Particulates in Rustenburg, South Africa

In this study, inhalable particulate matter was sampled using the TEOM series 1400a, the elemental composition of the particulate matter was determined using Scanning Electron Microscopy coupled with Energy Dispersive Spectrometer (SEM/EDS) and the concentration of particulate nitrates and sulphates was analyzed using Ion Chromatography (IC). These parameters were evaluated to obtain an estimate of the composition of inhalable particulate matter (PM10) in Rustenburg, South Africa. The toxicity was also determined in terms of ratios of toxic metals to PM10, as well as to elemental carbon, nitrates and sulphates. The components of PM10 were obtained as follows: organic, halides, sulphates, crustal metals, toxic metals, nitrates, and carbon. The main toxic metals were obtained in order of decreasing abundance as Cr>Pb>Ni>V. Seasonal variations showed high levels of PM10 and sulphates in spring and high nitrate levels in summer. The SEM/EDS showed the presence of atmospheric particles of complex composition including S, Si, Al, Mg, Ca, Pb, Fe, Cr, Ni, V, and Pb.

Assessment of natural radionuclide distribution in shore sediment samples collected from the North Dune beach, Henties Bay, Namibia

Abstract The activity concentrations of 238U, 232Th and 40K were determined using gamma spectrometry (HPGe detector) and their radiological hazards are presented in this study for shore sediment samples from the North Dune beach of Henties Bay, Namibia. The activity concentrations were found to range from 25.32 ± 1.24 Bq.kg−1 to 232.33 ± 0.62 Bq.kg−1 with an average value of 175.59 ± 0.92 Bq.kg −1 for 238U, BDL to 77.99 ± 45 Bq.kg−1 with an average value of 40.17 ± 27 Bq.kg−1 for 232Th and 222.39 ± 8 Bq.kg−1 to 482.16 ± 10 Bq.kg - 1 with an average value of 349.66 ± 8 Bq.kg−1 for 40K. In order to assess the radiological hazard of the shore sediment samples, the radiological hazard indices such as absorbed dose rates (ADR), radium equivalent (Req) annual effective dose equivalent (AEDE), the hazard indices (Hex and Hin), and the excess lifetime cancer risk (ELCR) were calculated. The values obtained in the present study were compared with world acceptable limits and it was found that the average values of radium equivalent (Req) and external hazard index (Hex) were below the world allowable limits. However, the average values of absorbed dose rates (ADR), annual effective dose equivalent (AEDE) (outdoor and indoor), internal hazard index (Hin) and excess lifetime cancer risk (ELCR) exceeded the world acceptable limits.

P290 The respiratory health effects of occupational exposure to charcoal dust among namibian charcoal factory workers

This is the first study that reports on the dose-response relationships between occupational exposure to charcoal dust, respiratory symptoms and lung function among charcoal-processing workers in Namibia. Methods: A cross-sectional study was conducted among 307 workers from charcoal factories in Namibia. All respondents completed interviewer-administered questionnaires. Spirometry was performed on a subset of the sample and ambient and resipirable dust levels were assessed in different work sections. Results: Exposure to respirable dust levels across most of the job categories was above occupational exposure limits, with packing and weighing having the highest dust exposure levels (median 27.7 mg/m3, range: 0.2–33.0 for the 8 hour time weighted average). A high prevalence of respiratory symptoms was observed among males and females respectively: for cough (39% and 22%), cough for more than 3 months (19.4% and 13%), breathlessness (21% and 35.5%), wheezing (29% and 26%) and phlegm (30.3% and 33%). Higher cumulative dust exposure (CDE) was associated with chronic cough, phlegm for most days, and doctor-diagnosed diseases. Ex-smokers had elevated odds ratio for phlegm for most days (OR: 1.2, 95% CI: 0.4–3.7), shortness of breath (OR: 1.3, 95% CI: 0.4-.4.1), and wheezy chest (OR: 1.6, CI: 0.5–4.9). Among those having lung function tests (n = 291), a lower mean predicted% FEV1 was observed (98.1% for male and 95.5% for female) among the higher exposed workers as compared to the low dust exposure category (FEV1%: 101.1% (males) and 104.1% (females). Conclusions: Charcoal dust levels exceeded the US OSHA recommended limit of 3.5 mg/m3 for carbon black containing material. Participants presented with exposure related adverse respiratory outcomes in a dose-response manner. Our findings suggest that stronger enforcement of regulations within the industry is required.

Occurrence of Toxic Trace Metals in Health- Significant Atmospheric Particles

-3 while at night-time, the concentrations ranged between 0.04 µg.m -3 and 0.8 μg.m -3 . The toxic elements Cr, Ni, V and Pb were identified in the PM 10 , PM 2.5 , PM 1.0 and PM<1 samples. The Cr concentrations exceeded the limits of 1 μg.m -3 for NIOSH and also the 1.5 μg.m -3 limit for APCEL. The WHO standards of 0.5 μg.m -3 and 1 μg.m -3 for Pb and V respectively were not exceeded. The study suggests the need for more prolonged, continuous studies so as to establish trends and seasonal variations in particulate matter and toxic metals.