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Team:Hannover/Safety/Saftey Heavy Metal
From 2014.igem.org
Additional rules and regulations
In our iGEM-project we use heavy metals to verify the binding activity of our Top 4Metal Binding Protein (T4MBP). Besides the common S1-lab rules, e.g. genetic engineering act (GenTG) and safety trainings, we therefore have to follow additional rules and regulations.
Our chosen metal-binding protein-domains are involved in heavy-metal-detoxification in their natural origin. Note that detoxication differs from detoxification. Detoxification is the process of removing toxins from the body while detoxication is the process of preventing toxic entities from entering the body in the first place. The domains are taken from Helix pomatia (roman snail – for Cd2+), Sacccharomyces cerevisiae (baker’s yeast – for Cu2+), Hordeum vulgare (barley – for Zn2+) and Fucus vesiculosus (bladder wrack – for As3+).
Risks
To proof a successful binding of our protein we used Cadmium nitrate tetrahydrate (Cd(NO3)2 • 4H2O), Copper (II) nitrate hydrate (Cu(NO3)2 • xH2O), Zinc nitrate hexahydrate (Zn(NO3)2 • 6H2O) und Arsenic (III) oxide (As2O3). Especially the cadmium and arsenic compounds are to be critically judged concerning lab-handling.
Cadmium is harmful to...
- the lung (emphysema) as well as
- to the kidneys (renal tubular dysfunction) (source 1).
Arsenic can cause...
- an acute toxicity together with
- an acute paralytic syndrome (symptoms: cardiovascular collapse, central nervous weakness and death within hours) and
- an acute gastrointestinal syndrome (symptoms e.g.: metallic or garlic-like taste, dry mouth, burning lips, headache, vomiting, possible multi-organ failure).
- Possible long-term exposure symptoms are e.g. fever, swelling of the liver, dark discoloration of the skin, sensory and motor neuropathy, encephalopathy (source 2).
- Besides arsenic is carcinogen, hence inhalation can affect the lung and ingestion might affect the bladder, kidneys, skin and lungs (source 2).
Also the safety risks concerning copper and zinc should not be neglected...
- copper compounds can cause an acute toxicity with acute hemolytic anemia, liver and kidney damage after a single exposure through ingestion (source 3).
- Zinc compounds like zinc sulfate – we used zinc nitrate – can cause headache, nausea, vomiting, loss of appetite and stomach cramps (source 4).
Handling
The handling of these chemicals and the dangers that can occur doing so take an intensive pre-test study of the current safety data sheet for granted.
Safety data sheet...
- Arsenic (III) oxide (As2O3) link
- Zinc nitrate hexahydrate (Zn(NO3)2 • 6H2O) link
- Copper (II) nitrate hydrate (Cu(NO3)2 • xH2O) link
- Cadmium nitrate tetrahydrate (Cd(NO3)2 • 4H2O) link
These sheets can also be taken as a basis for the correct and consistently declaration of all used vessels with the appropriate GHS (Globally Harmonized System of Classification and Labeling of Chemicals)pictograms. A risk assessment should always include the opinion of the supervisors and, if existing, the occupational health and safety officer. Especially in accordance to cadmium, the female lab-workers have to be explicitly informed about the hazards to the unborn child in case of a pregnancy. For the own safety and the safety of all lab-workers the precautions from the sheet should always be observed. They include the permanently wearing of lab coats, at least nitrile-gloves as well as a breathing mask and safety glasses if necessary.
Also the use of a fume hood while transferring the solid chemicals is necessary because of a possible aerosol generation. Furthermore the use of disposables is recommended, because of the easier removal in comparison to the solutions that accumulate by washing used glassware. These solutions, which in case of cadmium imply additional HNO3 and in case of arsenic imply additional HCl, have to be collected in special GHS-declared and acid-resistant cans for heavy metals. In the same way, the contaminated disposables have to be collected in a wide-neck drum declared with GHS-pictograms. It is necessary that the cans and drums are picked up to be disposed professionally by a responsible service. This avoids accidents through untrained staff. By collecting the contaminated solutions also the exposition of water organisms can be avoided. Anyway, should the chemicals, even if in a small amount enter the canalization, responsible department (e.g. environmental protection officer and the operations fault reporting point of the university) has to be informed immediately.
