Dust pollution in quarries pose various health risks to the workers including
respiratory ailments, skin and eye problems. Depending on the chemical
composition and the concentration of the dust, the workers are exposed to
inhalation of silica bearing dust thus being at risk of developing silicosis, a
fatal lung disease. Information on the chemical composition of the quarry dust
is important as it forms a vital baseline for among others the detection of the
undesirable health effects among the quarry workers. The aim of the study was
to find out the occupational health risks posed by the dust to the quarry
workers in Kajiado County, Kenya. The specific objectives of the study were
to find out the chemical composition of the limestone, phonolite and
pozzolana quarry dust; concentration of silica, chromium, cadmium and lead
in the dust; and to assess the quarry workers awareness of the safety and the
health risks in the quarry. Purposive and random sampling was used to get 110
workers for the study and dust samples were collected at 0m, 25m and 50m
from the point source of the dust using a dust sampling pump set at 2L/min
and run for 120 minutes. The chemical composition of the quarry dust; and
the concentration of silica and the heavy metals (chromium, cadmium and
lead) were done using standard laboratory procedures. A questionnaire was
administered to the workers to find out the occupational safety and health risks
and the workers’ awareness levels of the risks. The study revealed that the
quarry dust was composed of various chemical compounds and naturally
occurring elements at various concentrations, includingSiO2 (3.26% - 35.9%),
Cr (9.0-22.18ppm) and Pb (15.5-41.14ppm). The study found that the dust
concentration was 86.52mg/m3
, SiO2 concentration was 0.62mg/m3
, that of Cr
was 5.92mg/m3
and of Pb was 9.24mg/m3
. The dust concentration showed a
negative correlation with distance, r = -0.41227 and p-value of 0.0103. The
comparisons of mean dust concentrations forSiO2, Cr and Pb in limestone,
phonolite and pozzolana showed p<0.0001, p=0.2071 and p=1460,
respectively. The study showed that 60.55%) of the workers exhibited cough,
10% had skin irritation and 2.75%) experienced eye irritation. The study
revealed that the quarry workers’ awareness of the safety and health risks was
94.5%, but only 16.51% used protective clothing. The study concluded that
the dust concentrations failed to meet the Occupational Safety and Health
Administration, (OSHA) standards and therefore exposed the workers to the
risk of respiratory, skin and eye health problems. It is recommended that
measures should be put in place to mitigate the high dust generation at the
quarries and the workers should be sensitized to use protective clothing while
at work. Clinical research should be conducted on the quarry workers in order
to ascertain any development of silicosis.