Bio Chem Flashcards
Does a persistent chemical have a high boiling point or low boiling point
High boiling point
What is meant by LD50
LD50 is the amount of substance administered by a defined route of entry over a specific period that is expected to cause the death of 50% of a defined animal population.
What Is ED50
50% probability of effect.
Why are solids rarely used in chemical weapons?
Solids can be used but these are difficult to disseminate.
What’s vapour pressure depend on?
Vapour pressure depends on temperature.
Will a substance with a higher vapour pressure evaporate more or less quickly than one with low vapour pressure?
A substance with a high vapour pressure will evaporate more quickly than one with a low vapour pressure.
What is the calculation of max concentration?
(1 x 10^6 x vapour pressure (torr))/760 in ppm
What is the standard vapour pressure of mustard gas at 20 degrees C?
0.072 torr
What is the maximum concentration of mustard gas?
96 ppm (610mg/m^3)
What is vapour density?
Vapour density is the ratio of the molecular mass of the substance to the average molecular mass of air.
Non persistent agents are? (3 things)
Volatile, low boiling point liquid (or gases), with high vapour pressures. E.g. chlorine, phosgene
Persistent agents are? (3 things)
Non-volatile, high boiling point liquids (or solids), with low vapour pressures.
What are non persistent chemicals used for?
Produce a toxic cloud of vapour which is often heavier than air, thus capable of penetrating foxholes and bunkers.
Persistent chemical agents are used for?
These are usually liquids which are used to produced a chemical rain or spray to contaminate troops, ground or equipment. Many organic liquids are able to penetrate the skin.
What is the arbitrary between persistent and non persistent?
The vapour pressure.
Does the persistence of the chemical agent increase as the temperature falls?
Yes.
Why can mixtures of gases be denser than air?
Because the molecules are heavier, because they are colder or both can apply.
What happens to the liquid when it’s goes from vapour pressure to atmospheric pressure (in an open system)?
The liquid will boil. The liquid will not be a liquid above its boiling point unless it is contained under pressure. Liquids will start to evaporate below the boiling point, how much depends on the surface area.
What is a cold cloud?
Any vapour held under pressure or chemicals that evaporate quickly will form a cold cloud. Once the pressure is released from a gas that has been liquified by pressure, it has to evaporate, or some of it evaporates and some of it is cooled below its boiling point.
what happens when a cold cloud is formed?
A cloud is produced which is colder and denser than air.
How soluble is mustard in water?
Sparingly soluble (0.8gLitre^-1)
What is more soluble, nerve agents or mustard?
Nerve agents are more soluble and may hydrolyse.
When hydrogen cyanide dissolves in water can you ingest it?
Hydrogen cyanide is soluble but the solution is still poisonous if ingested.
Can phosgene be destoryed in water?
Phosgene is soluble and is rapidly destroyed in water.
After Lewisites hydrolyse in humid air and are destoryed, what do they leave behind?
It leaves arsenic - which is toxic.
What happens when the surface tension of a liquid is lower than the surface energy of the surface on which it lands?
It will spread.
What do the new Mk IVa suits been treated to stop?
Mk IVa have been treated to prevent agent spreading.
What is the surface tension of bare metal?
100 mN m^-1
What is the surface tension of water?
72 mN m^-1
What is the surface tension of Mustard?
42 Nm m^-1
If the surface tension of a liquid is lower than the surface tension of a material what happens?
It will spread.
How are Vapours removed from the air?
By physical adsorption.
What does the the uptake of a gas by the adsorption depend upon?
To a great extent it depends upon its boiling point.
If a substance has a low boiling point what else will be low?
It will have a low inter-molecular forces. These are the same forces which hold it to the surface of a solid.
What can Adsorption be viewed as?
Adsorption can be viewed as turning a vapour back to a liqiuid and is most effective at a given concentration for high boiling point liquids.
What happens when Charcoal capacity is reached for high boiling point substances?
Charcoal wil have capacity for high boiling point subtances =until a concentraion is reached where all the pores are full.
What do respirators have in them?
Chemicals to remove vapours below the boiling point of 65 degrees C.
What is the boiling point of Hydrogen Cyanide?
26 Degrees C
What is the boiling point of Phosgene?
8 Degrees C
What is the boiling point of Arsine?
-55 Degrees C
What is military activated carbon impregnated with?
Copper, Copper oxide, Silver, Chromium hydrolyses cyanogen, and Triethylaminediamine.
Can chemical agents permeate with rubbers and plastics?
Some rubbber and plastics can be permeated by Chemical Agents.
If a plastic is permeated how can you tell?
The polymer will often swell or soften, eventually agents vapour will pass through the polymer and come out the other side.
What will the mpt and bpt of a chemcial determine?
How it will be dispersed, how long it will remain a liquid hazard when dispersed, the maximum vapour concentration that can reach in air at different temperature as it evaporates, and the design of respirators and protective clothiung provided to protect against it.
The surface tension of a chemical agent will determine?
How it interacts with equipment and clothing.
The relationship between the liquid properties of the chemical agent and polymers will determine?
If the agent can penetrate the polymer to prolong a vapour hazard, and if it can pass through the polymer barrier.
Name me some good old fashion poisons!
Ricin, arsenic, chlorine, mercury, nicotine, chloroform, phosgene, nerve gases, cyanide, etc..
What is dose?
The amount of substance that comes into contact with a living organism. (mg/kg)
How is concentration if exposed from the air measured in?
mg m^-3
How is concentration x time measured in?
mg min m^-3
what is ED50?
50% probablilty of effect.
What is LD50?
50% probability of lethality.
What is ID50?
50% probability of incapacity.
What is Haber rule?
Haber Rule = Concentration x time
What is LCt
Leathal exposure. Measure in mg min m^-3
What is ICt
Incapacitating exposure. Measure in mg min m^-3
What are the 5 main routes of entry?
Gastrointestinal tract - ingestion
Respiratory - inhalation
Percutaneous - Skin (demal)
Subcutaneous - under the skin
Parenteral - Other routes eg injection, intravenous etc
What Physiological systems that can be affected?
Respiratory, integumentary (skin), Cardiovascular, lymphatic and immune, and Nervous
What can pass through the membrane lining of the lungs?
Oxygen, Nitrogen, Water.
How are large particals removed from the lungs?
They make contact with the bronchiole level and be removed by the ciliated epithelium.
What do very small particle s penetrate in the lung including gases and vapours?
Alveoli.
What happens to the lung when biological agents infect it?
It produces an imflammatory response.
What are the functions of the skin?
Prevent water loss
Protect underlying organs
Provide touch and temperature information
control body temperature
intact skin prevents entry of micro organisms and may chemicals
What two things are the bodies first defence against disease causing microoganisms?
Skin and mucus
What dose mucus trap?
Mucus traps microbes that enter the respiratory and intestinal tracts.
What does lysozymes do? and where are they found?
An enzyme that breaks down cell walls of certain bacteria, found in sweat, tears, saliva, nasal secretions, and tissue fluids.
What are the vulnerabilities of the skin?
Disease can enter through skin through cuts. Chemicals which can penetrate the skin and produce whole body effects after being transported through the blood stream. Skin damaging agents producesing local effects.
What does the cardiovascular system consist of?
Heart and blood vessels.
What is transported through the body by blood?
O2 as Oxyhaemoglobin from the lungs and CO2 to the lungs. As well as nutrients, enzymes and hormones.
Is blood an organ in its own right?
Yes.
What are white blood cells called?
Leucocytes
What is the brain surrounded by?
Fatty cells with tight junctions to increase barrier effect.
What two things must a substance have to enter the Central Nervous system?
Water solubilty to be soluble in the bloodstream, and lipid solubility to cross the blood brain barrier.
What are synapses?
Junction between nerves or nerve and muscle.
Messages transmitted by release and subsequent reception of messenger chemical acetylcholine.
What does botulinum do?
Botulinum toxin blocks the release of acetylcholine.
What does atropine do?
Atropine block receptors for acetylcholine,
What is the lymphatic system?
Another circulation system of the body, drains interstitial fluid and transports lipids. The lymphatic tissue functions in surveillance and defence.
What are some types of chemical agents?
Chocking or pulmonary agents, Blood agents, vesicant agents, incapacitating agents, nerve agents.
What are the physiological action of choking agents?
Chocking agents attact the respiratory tract, Inhalation produces chocking, coughing, tightness of the chest, pain in breathing, and cyanosis.
What is Phosgene’s toxcity levels?
WEL 0.25 mg m^-3
ICt50 1600 mg min m^-3
LCt50 3200 mg min m^-3
saftey ratio LCt50/ICt50=2
Roughly how long does phosgene take to kill you?
around 3.5 hours with visible symptons being around an hour before death.
Name some choking agents?
Phosgene, Diphosgene, chloropicirin.
Treatment for choking agents?
Fresh air, remove contaminated clothing, wash contaminated area with soap and water, irrigate eyes, Do not allow victim to choke on own vomit, evacuate to hospital.
How are blood agents primary absorbed?
Through breathing.
What do blood agents do to the enzymes?
They block enzymes which transfers oxygen from blood to the tissues.
What are some blood agent symptoms?
Weakness, headache, constriction of the throat. Increase in breathing and heart rate/ Victims will lose consciousness.
What are some blood agents?
Hydrogen cyanide, Cyanogen chloride, arsine
Are vesicant agents (Blister agents) blister agents leathal?
No
Name some characteristics of mustard gas?
Power alkylating agent, general cell posison, skin damage, moist skin more effected than dry skin
Mustard vapour doses.
LCt50(inhalation) 1500 mg min m-3
LCt50(skin) 10000 mg min m-3
ICt50(skin) 2000 mg min m-3
ICt50(eye) 200 mg min m-3
Sulphur mustard treatment?
- Remove victim from contaminated area
- Strip or cut off contaminated clothing
- Decontaminate with Fuller’s Earth followed by
soap and lukewarm water - Skin abrasion (used to be part of the treatment)
- Monitor (including monitoring for contamination)
- Hospitalisation
Incapacitating agents
Non-lethal, except in exceptional circumstances
* They incapacitate, without causing permanent harm
* Their LD50 must be much larger than ID50
Ratio»_space;50
* Physical incapacitants and mental incapacitants
* Most are solids at room temperature and are delivered
as smokes or vapourised and delivered as an aerosol
Are incapacitants compliant in CWC?
Prohibited as weapons of war
But have legitimate uses in Policing and Military training
types of physical incapacitants?
Sternutators, tear agents, urticants,
Characteristics of incapacitating agents?
Substances must not endanger life
Not cause permanent damage – either toxicological or physical
Recovery would not require medical treatment
Such agents must be highly potent, easy to store and deliverable as practical munitions
What does CS cause (Ortho- Chlorobenzlidene malonitrile)
Intense smarting of the eyes and a burning sensation in nose/throat
What is an issue with CR (dibenzoxazepine) when used in confined spaces?
Can be lethal.
What is a commonly used Tear Agent?
OC- pepper spray. Produced from the capsaicin family of plants
What is sternutators also known as?
Sneezing vomiting or nose agents.
What are Urticants also known as?
Nettle agents.
What can Urticants cause?
Cause local tissue destruction on contact with the skin and mucous membranes
What are some Incapacitants (Psychochemical agents)?
- Central Nervous System Depressants
- Central Nervous System Stimulants
- Psychedelic drugs
What are some Central nervous system stimulants?
- Cocaine
- Amphetamine
- Dextraamphetamine
- Methylamphetamine
What do Central nervous system stimulants do?
Agents which cause excessive nervous activity. The effect to flood the brain with too much information disrupting concentration and the ability to act in a sustained and purposeful manner
symptoms of drugs?
looking like goose 24/7
Produce Combination of Confusion
Distorted Vision
Hallucinations
Fear & Anxiety
Uncontrollable laughter
Inertia and Apathy
Schizophrenic symptoms
Which family of chemicals do Nerve agents all belong to?
organophosphorus esters
All are colourless, odourless liquids
What are types of G nerve agents?
- Tabun (GA)
- Sarin (GB)
- Soman (GD)
- Cyclosarin (GF)
What are type of V nerve agents?
- VX
- RVX
Which are the most persistent of the nerve agents?
The V agents are the most toxic and persistent of the nerve agents
What was the US standard persistent nerve agent?
VX
Where are you most likely to incounter VX
VX is most likely to be encountered as a liquid
contaminant on the ground or as an airborne
aerosol than as a vapour
Sympotons of nerve agent poisoning?
miosis, tightness in chest, dizziness, incoordination, prostration, +++ secretions, loss of consciousness, generalised muscle spasms, convulsions, obstructed airway, respiratory failure, circulatory, collapse, death
what happens after a nerve agent attack?
Nerve agents bind to AChE and prevent the hydrolysis of ACh – the receptors are continually stimulated so the muscle goes into spasm
what are the mechanism of an action of nerve agents?
Muscular function is controlled by a chemical process at neuromuscular junctions called synapses
* Electrical impulses from the brain release neurotransmitter ACh (acetylcholine) at these points
* ACh stimulates the muscle to contract
* Once the muscle has been stimulated an enzyme AChE (acetylcholinesterase) destroys ACh so no further signal is transmitted.
* Nerve agents block AChE allowing ACh to continually stimulate muscle contraction
* This eventually causes respiratory and cardiac failure
What are some common toxicity terms?
TLV Threshold Limit Value
RL/CL UK Recommended/Control Limits
WEL Workplace Exposure Limit
TWA Time Weighted Average
NOEL No Observable Effect Level
STEL/LTEL Short (15 min) and long (8 hrs) term exposure limits
IDLH Immediately Dangerous to Life and Health
What does every chemical supplier in the UK meant to produce for their chemicals?
Safety data sheets.
What is the definition of a toxic chemical by CWC and CWA?
“Any chemical which through its chemical action on life processes can cause death, temporary incapacitation or permanent harm to humans or animals.
This includes all such chemicals, regardless of their origin or of their method of production, and regardless of whether they are produced in facilities, in munitions or elsewhere.”
What are the classification of biological agents?
Bacteria, viruses, Rickettsia, fungal
What is the definition of Infectivity?
Measure of ability to cause disease. High infectivity means that only a small number of organisms are needed to cause disease.
What is the definition of virulence?
Different strains have different severity. More virulent strains result in the most severe disease.
What arbitrary temperature is used to determine if it is persistent or non?
160 Degrees C.
What is the use for detection?
Provide a timely warning that an event has occurred.
Triggers adoption of protective measures, to avoid exposure/contamination as well as informing the wider force.
Detection is needed for warning and protection.
What is the use of monitoring?
Provide on going real time output scaled to the hazard severity, often to facilitate recce/survey or hazard management or mitigation.
What are the characteristics of identification?
In field, uses early detection triggers, based on pre-made libraries.
What are the characteristics of Analysis?
Off site, give accurate results, samples need to transporting.
What are the key points for using Humans as detectors?
Nerve agents causes the pupils to contract at low levels. Observe for liquids or vapours. Smell for distinct smells. Use sight to see for colour of agent.
What things do you need to consider from an intrument?
Do we need to know exactly what the agent is?
Do we need to know what the concentration is?
Do we need to know exactly where the contamination is?
What activites are impeded without this data?
What about changes in its distribution?
What about tracking downwind hazards?
What do you need in an instrument?
Sensitivity, specificity, reliability, response, stability, simplicity, consumables, cost
What happens if your instrument is too sensitive?
Higher false alarm rates.
Why is speed of response important?
Gives timely warning.
Why may speed of an instrument may not be important?
Speed may not be so vital for contamination control, giving an all clear or for analytical sampling.
What are some positives about colorimetric?
Cheap, can be specific.
What does 1 colour detector paper show it is not?
1 colour detector paper shows that liquid is not water.
What does 3 colour detector paper show?
3 colour detector paper discriminates between agent types.
What are draeger tubes used for?
Specific wet chemistry that causes colour changes for specific chemicals.
What does flame photometry use to determine chemicals?
Uses hydrogen in air flame and optical detection.
What does flame photometry tell you?
You can tell whether certain atoms are present in a sample. Each element has a different sensitivity and dynamic range.
What are some positives of IMS (Ion Mobility Spectroscopy)?
Fast and sensitive.
What does CAM stand for?
Chemical agent monitor.
What are the pros of using IR or FTIR?
Very fast, highly sensitive, relatively simple, internally calibrated, non destructive.
What are the Cons of IR or FTIR?
Cant identify pure elements, solutions or contaminants less then 10% concentration or biological agents.
What is the Bruker RAPID System used for?
Stand off detector for atmospheric pollutants.
How does a gas chromatography work?
Sample is injected into the gas chromatograph either as liquid or vapour. travels through a thin silica packed column contained within an over pushed through using a carrier gas. As the sample travels through the column its different components will separate based on their composition and molecular mass.
Using mass spectroscopy what information does scanning the different ions give you?
The different ions formed give important information about the nature and structure of the molecule.
I was going to put a point about TIC Sensors but what are the chances it comes up in the exam?
Used for detection for environmental monitoring.
What are some characteristics of Carbon Monoxide?
It does not smell or taste, completely colourless, will pass straight through respirator both the s10 and GSR. very common and cheap to get commercial detectors.
What are the symptoms of Carbon monoxide poisoning?
Tension headache, dizziness, feeling and being sick, tiredness and confusion, stomach pain, shortness of breath and difficult breathing.
How small is ebola?
0.97um
What are the pros of using Assays?
A bio agent detector. Cheap fast and reliable, minimal training required.
Can a GSR be used in evidence after you commit a crime?
Yes you dirty boy
What some readily available detectors?
Assay, TIC sensor, Mass spectroscopy, gas chromatography, Raman. RAPID.
examples of bacteria
Anthrax, plague, tularaemia, chloera
