Exposure to quartz in South African sandy soil farms is a matter of serious concern, warns new study.
Respirable quartz is associated with the development of silicosis, lung cancer, pulmonary tuberculosis and other airway diseases. The National Institute for Occupational Safety and Health (NIOSH) has estimated that at least 1.7 million U.S. workers are exposed to respirable crystalline silica in a variety of industries and occupations, including construction, sandblasting and mining.
South African Researchers sought to review the published literature on respirable
quartz exposure and associated disease in agricultural related
settings systematically and to describe personal respirable
dust and quartz measurements collected on a sandy soil farm
in the Free State province of South Africa.
They searched all published studies on exposure to respirable silica
and quartz in agriculture and related settings (to June 2009). From farm in the sandy soil region of the Free State
province of South Africa producing typical crops, they collected 38 respirable dust and respirable quartz
measurements from July 2006-August 2008
during major farming operations.
In total, 17 studies were identified: 11 investigated
respirable quartz exposure on farms and 6 quartz-related diseases
in agricultural settings. They provided convincing evidence
of a respirable quartz risk on sandy soil farms but scant evidence
of associated disease. Respirable quartz measurements from the
South African farm ranged from not detectable to risk levels, even though the majority of respirable dust
concentrations were well below commonly used occupational
The researchers led by Andrew J. Swanepoe wrote in the Journal of Occupational Hygiene, "Despite its ubiquity, little is known about quartz
exposure in the agricultural industry; but this study demonstrates
significant potential for overexposure in some settings. Further
research is required to quantify quartz exposure and identify
settings and tasks that place farmers and farmworkers at risk
of quartz-associated diseases so that controls can be implemented."