1. Waste substances can be divided into 2 types:
Can be thrown into the sink
- The substance with a pH value between 5 to 9
- Solution with low concentration
- Examples
- Neutral substances
- Weak acids
- Weak alkalis
Cannot be thrown into the sink
- Solid waste
- The substance with a pH value less than 5 or more than 9
- Organic solvent
- Toxic substance
- Heavy metal
- Organic waste
- Examples;
- Acid
- Grease
- Oil
- Oil paint
- Hydrogen peroxide
- Microbes
- Carcasses
- Radioactive waste
- Volatile substances
- Reactive substances
2. Way to dispose of toxic chemical substances
- Treat the waste before dispose
- Store in a closed container and labelled it
3. Standard operating procedure (SOP) for biological waste disposal
Examples |
SOP |
A: Sharp waste
- Syringe needles
- Glass slides
- Glass pipettes
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Place the wastes in sharps waste bins before disposed
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B: Non-sharp waste
- Used tissue
- Cotton wools
- Gloves
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- Place the waste into biohazard plastic bags
- Wastes collected must be autoclaved before being disposed
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C: Carcasses, organs or tissues of organisms
- Animal carcasses
- Animal tissues
- Plant tissues
- Biological specimens
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- Wrap the wastes in tissue paper and put them into biohazard plastic bags
- Waste collected must be autoclaved before being disposed
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D: Bodily fluid waste
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- Waste is decontaminated in autoclave machines
- Dispose of wastes directly into the sewage system through the laboratory sinks or toilets
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4. Steps to Handle Accidents in the Laboratory
Accidents of chemical substances spillage |
- Inform the teacher or laboratory assistance
- Make the spill area a restricted area
- Prevent the spillage from spreading using sand
- Scoop the spilled chemical substances
- Throw away safety
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Accidents of a mercury spill |
- Inform the teacher or laboratory assistance
- Make the spill area a restricted area
- Pour sulphur to cover the spill
- Inform the fire department
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* Mercury is toxic
It can attack the nervous system, digestive tract, reproductory system and kidneys.
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