Silica
Crystalline SiO2 (quartz)
Where is quartz found
Sedimentary, Igneous and metamorphic rocks
Main mineral in desert sand and beaches
Quartz
Building products that contain silica
concrete, bricks
Cells that attack silica
Macrophages
What do macrophages do
- engulf silica to try and dissolve crystals
- carry silica into walls of the lung
Forms around dead cells
Scar tissue
Accumulation of excess fibrous connective tissue (fibrosis) leads to what
thickening of lung walls which causes reduced O2 supply to blood
Scar tissue formation caused by
Accumulation of excess fibrous connective tissue (fibrosis)
Consequence of scar tissue formation in lungs
Shortness of breath
Pulmonary fibrosis
Progressive, fatal lung disease - few survive more than 3-5yrs after diagnosis
Silicosis cause
Exposure to crystalline silica
Occupations known to expose workers to crystalline silica
- mining
- construction
- tunnel work
- masonry
- sand blasting
- glass manufacturing
- ceramics
- steel work
- quarrying
- stone cutting
Symptoms of acute silicosis
fever, sharp chest pain, breathing difficulty
Chronic silicosis symptoms
- cough
- breathing difficulty
- excess phlegm
- bronchitis-like
- wheezing
- abnormal chest x-ray
Chromic symptoms of silicosis develop ____________ and acute develop ____________
slow, suddenly
Leg swelling, increased breathing rate, bluish discolouration of lips
Effects of extensive scarring in lung tissue over time
Is silicosis reversible/curable
No
Ways to reduce dust exposure
Water: suppress dust
Vacuums: capture dust
Respirator
Good hygiene at work with dust exposure
- no eating or drinking in dusty areas
- washing hands/face
- smoking outside dusty area
- change of clothes
- shower before leaving
- park cars away
Where is silica found in relation to coal
In the sandstone and shale layers (deeper than coal)
Black lung
Coal workers pneumoconiosis caused by long-term exposure to coal dust
