Industrial Toxicology Flashcards
when were systematic descriptions of occupational diseases apparent ?
not until the 18th century but it had been known for a long time that some occupations came with increased risk of ill health
what is industrial toxicology?
it is an understanding of hazards, procedures to minimise the risk of harm, disaster planning
about risk assessments and putting in risk management procedures to reduce risk
concerns protecting health of people having to work with chemical or physical hazards
what did bernadino ramazzini publish ?
in 1700 published a seminal work= De Morbis Artificum Diatribe
- detailed description of occupational diseases
- emphasised the importance of establishing occupation when compiling patient history
what was bernadino ramazzini?
the founder of occupational toxicology
what did charles turner thackrah do ?
he was the founder of leeds medical school
put pressure on government to improve social and working conditions- caused government to introduce acts
19th century
what did sir george baker do ?
identified lead poisoning as probable cause of devonshire colic
what did percival pott do ?
drew attention to the high rate of scrotal cancer in chimney sweepers
what happened between 1830s-1890?
various factory acts were passed
- state factory inspectorate - only 4 initially, then 35 by 1868- tried to ensure sanitary conditions were improved
- women and children banned from working with white lead
- standards set for ventilation, protective clothing, etc
- minimum age for child labour
- limited hours in which children and women could work
what was passed in 1895?
factory and workshop act - notification of industrial diseases caused by lead, phosphorous, aresenic etc - government had to be notified of any diseases caused by these substances
what was passed in 1897?
workmens compensation act - established the principle that those injured at work should be compensated
what was passed in 1898?
thomas legge the first medical inspector of factories
what was passed in 1911?
national health insurance act- covered manual workers for sickness and disablement benefits - not that successful
what was passed in 1946?
national insurance industrial injuries act- provided compensation for loss of ability to work
what was passed in 1974?
health and safety at work act- underpins all current legislations on safety at work - a lot has been over taken by EU legislations
what is asbestos?
naturally occurring fibrous material
crystalline structure consisting of layers of silicon dioxide bonded to layers of metal oxides
known as magic mineral- because it doesnt burn and is resistant to many chemical agents
it is nearly inert
what are asbestos fibres classified as ?
serpentine fibres= fibres often form bundles which are curvilinear and have splayed ends
amphibole= fibres tend to be straight
what are the 3 main types of asbestos ?
chrysotile- white asbestos- only serpentine form in commercial use- major form that is mined as it is the most versatile form because its fibres are long- spun into yarn and then into fabrics
crocidolite- blue asbestos- shorter more flexible fibres
amosite- brown asbestos- fibres are not flexible so its used in construction
what country is most of the chrysotile and amosite mined?
chrysotile- canada
amosite- south africa
what are amosite fibres fabricated into ?
into slabs or sheets for thermal insulation
when does the asbestos industry date back to ?
1860
what did lucy deane do ?
in the late 1800s she was one of the UKs first women inspectors factories and she voiced concern of lung disease prevalence in asbestos workers
but in 1906 compensation was not given as it wasnt included as part of the cause of the disease
what happened in the 1920s?
first published reports of lung disease in uk factory workers exposed to asbestos
- reports of pulmonary fibrosis
what was clear by 1930 and what was passed in 1931?
1930- clear that asbestos dust could lead to asbestosis
1931- asbestos regulations act - try to minimise exposure but technology wasnt available to do that
what was passed in 1968/9?
asbestos regulations- the regulations before were not adequate
- however in this act there was no consideration that asbestos could induce bronchial carcinom and malignant mesothelioma
what happened in 1976?
massacre at hebden bridge
- intense media campaign to cause advisory committee on asbestos to review the 1968 act and recommend safer levels of exposure
what happened in 1982?
yorkshire TVs Alice- a fight for life
what happened in 2003?
european commission passed a directive which effectively banned the use of asbestos from april 2006
- 52 countries banned it
- but its still mined in some countries, particularly developing countries
what do asbestos fibres cause ?
inflammation and progressive fibrosis of the lungs
lung cancer and mesothelioma
by the 1950s what were the statistics of asbestos and lung cancer?
14% of patients with aasbestosis also had lung cancer
what did sir richard doll show?
showed that the risk of lung cancer in men employed for 20 years or more in the asbestos industry had a 10x greater chance of developing lung cancer compared to general pop
what is mesothelioma?
rare type of cancer which mainly affects the pleura and peritoneum
-marked increase over last 40 years
what is a safe level of exposure to asbestos ?
none
what is the expected number of deaths in the uk from mesothelioma by 2050?
90000 deaths
how many people each year die from asbestos related diseases?
> 100000
what is a key reason why asbestos fibres cause lung cancer and mesothelioma ?
its biopersistance - once inhaled they are slowly cleared from the lungs as the fibres are poorly soluble and many are too long to be removed by phagocytes and the ciliated epithelium
what can happen with chrysotile when it is inhaled ?
the fibres can split longitudinally so numbers may actually increase with time rather than decrease
what is the persistence of asbestos thought to cause?
a chronic inflammatory response which ultimately leads to pulmonary fibrosis
some asbestos fibres are phagocytosed by pulmonary phagocytes but then the phagocytic vesicles rupture spilling proteolytic enzymes into phagocyte cytoplasm- this kills the phagocyte and causes both the fiibres and the destructive enzymes to be released into lung tissue from the dead cells = inflammatory reaction
what are the lung defence mechanisms ?
cough
mucociliary escalator - ciliated epithelial cells - mucus traps the particles and we swallow it to kill them
macrophages– engulf material to remove it
what can happen if mineral and vegetable dust isnt cleared
?
may lead to inflammatory and fibrotic responses
- fibroblasts pump out type 1 collagen which decreases the amount of type 3 collagen
- type 1 is less flexible so the matrix is less flexible
- this makes it harder to exchange gases
other than its persistence what is another important factor of asbestos fibres?
surface chemistry
- shown that it can trigger the formation of reactive oxygen species by cells and some have found this to be linked to induction of mutagenesis and carcinogenicity
what do asbestos fibres contain ?
iron (2)
this can catalyse hydroxyl radical formation leading to lipid peroxidation and DNA damage
what does inhalation of coal dust cause ?
pneumoconisosis (anthracosis)
what does exposure to cotton fibres cause ?
byssinosis- inflammatory disease of the lungs
what does exposure to fungal spores cause ?
farmers lungs- inflammatory disease of the lungs
what is the issue with the spodden valley development ?
it was a site of major factories for asbestos and now they want to build houses there, however asbestos is largely inert and persistent so therefore it will still be there
