Particulate exposures (PM4) and respiratory symptoms in waste reclaimers at Onderstepoort landfill site

Abstract

Background: A landfill site is a site for the disposal of waste materials and it is the oldest form of waste treatment. In developing countries, informal recycling proves effective in reducing the amount of waste disposed of at landfills, thus prolonging their lifespan. Waste reclaimers make a living by selling the reclaimed waste to buy-back centres that act as middlemen between waste reclaimers and recycling facilities. As the informal reclaiming sector advances and continues to benefit waste management systems, growing concerns persist regarding the wellbeing of reclaimers while on landfills. Health and safety at the workplace is addressed directly in the Sustainable Development Goal Targets of the department of environmental affairs. However, implementation of these goals is not clearly cascaded to municipalities. There are an estimated 88 000 waste reclaimers in South Africa. The personal exposure levels of waste reclaimers to particulate matter with a 50% median cut point at an aerodynamic diameter of 4 m (PM4) at landfills as well as the respiratory symptoms resulting from such exposure are not known in South Africa, particularly at the Onderstepoort landfill site located in the City of Tshwane. Aim: The overall study aim was to determine if there is any association between personal and ambient PM4 exposure of waste reclaimers at the selected landfill site and their respiratory symptoms. Method: The study applied a cross-sectional epidemiology design. Personal PM4 and soot exposure measurement and respiratory symptoms assessment were conducted over a period of nine days in autumn (April 2016). Soil samples were collected to determine if the chemical composition was traceable to the soil in the area. Results and discussions: PM4 exposure was well below regulated limits. However, the 1 mg/m3 proposed limit as recommended by the Institute of Occupational Medicine, Australian Institute of Occupational Hygiene and the British trade union congress, was exceeded. Silica (alpha-quartz) was further detected in two personal samples. A high silica (non-specific) content of was also found in three soil samples. Thus, silica exposure may be traceable to the soil used for waste compaction. There may also be variation in the soil used for waste compaction. No significant association between personal PM4 or soot exposure and respiratory symptoms was detected. However, the number of years of working on the landfill was a significant predictor for reporting of cough symptoms and nasal congestion. Age and currently having a cold were risk factors for having phlegm. Conclusion and recommendations: Age, daily work hours, years of working on the landfill, personal soot exposure and being a former smoker were found to be predictors for respiratory symptoms in the univariate analyses. Further studies with larger sample sizes are required to determine the extent of risk factors associated with working on landfills. The lack of association between personal PM4 and respiratory symptoms may have been a result of the type of study design, i.e. cross-sectional design. Seasonal variation may present variations in symptoms. Fieldwork was only conducted during nine days in April 2016. The presence of alpha-quartz silica in the personal samples should be investigated further to determine if levels exceed prescribed limits. Further investigation is required to determine the impact of soil variation in the landfill on waste reclaimers particulate exposures and respiratory symptoms they experience. Control measures should be aimed at maintaining low particulate exposure levels. Personal soot exposure levels may be an indication of exposure to fossil fuels such as diesel particulates from the waste offloading trucks. This may warrant further studies to investigate diesel particulate exposure on the landfill.