natural mineral particles: risks and their control anthony seaton
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Natural mineral particles: risks and their control
Anthony Seaton
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Hazard and risk
• Hazard = potential to do harm (from the Arabic for gaming dice)
• Risk = the likelihood of harm occurring (but needs qualification by the perceived type/seriousness of the anticipated injury)
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General rules for reduction of risk from inhaled substances.
• Good information for exposed public
• Total avoidance (eg substitution, migration)
• Exposure reduction– Limit duration of exposure– Reduce/modify activities likely to increase exposure– Personal protection (eg respirators, filtered vehicle
cabs)
• Audit or surveillance of effectiveness.
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Assessment of hazardFolk law – not to be despised!
– Often the first indication of hazards
– Always worth talking to local people
• Toxicology – not always to be swallowed whole!– What is the target?– Problems with dose and
extrapolations– Problems with animal and cell
models.
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Considering risk
• Likelihood of exposure• Intensity of exposure• Duration of exposure• Toxic potential of dust
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Assessment of risk• How toxic to the lungs/other organs?• Ergonomics
– Personal behaviour (eg children, risk takers)– Activity levels (eg workers moving ash)
• Personal susceptibility– Nutritional– Genetic
• Epidemiology– Direct study of populations– Analogy from other, earlier studies
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Risk reduction
• How toxic is the dust?– Mineralogy and analogy– Toxicology
• Understand the population and geography– Can they be moved?– How long will exposure last?– How will exposures be distributed?
• Reduce exposures– Concentration– Duration
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Oil crisis looming -
where are the US energy reserves?In the Rocky Mountain shale deposits.
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Joseph Bell(Sherlock Holmes)
described skin cancer in shale oil workers in 1876
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Mineralogy of miner’s lung and of the W Lothian shale seam (from Hunterian museum)
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What are the health effects of oil shale
exploitation?• Mortality study of 1960 cohort of
Scottish oil-shale workers
• Follow-up study of survivors, for skin and lung disease
• case control study of lung cancer in W Lothian– (Am J Indust Med 1986; 9: 409 et
seq)
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An analogy for NMD – silicosis in metal miners
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An analogy for NMD – COPD in coal miners
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An analogy for NMD – simple pneumoconiosis in coal miners
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Montserrat:some practical
measures
• Evacuation and rehousing• Exclusion zone• Assessment of mineralogy/toxicity of dust• Assessment of risks from dust inhalation• Information on risk reduction measures• Provision of masks• Population studies to refine risk estimates
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Air quality standards or guidelines?
• Problems – – with different dusts– with regulation, monitoring and compliance– with lack of epidemiology
• But could be part of a published management strategy, based on analogous mineralogical, epidemiological and toxicological evidence.
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Thank you
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An interesting emergency!
68-year old ex-miner, one week post RU lobectomy
Increasingly wheezy - put on respirator
Diagnosis - acute asthma
Treatment - steroids and bronchodilators
Outcome - off respirator, and………!
(Thorax 1981;36:412)
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….Pathology report: PMF:“Which coal mine did you work in?”“I was a shale miner”
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An analogy for NMD – complicated pneumoconiosis in coal miners