Safety, Ethical & Environmental Issues in Chemistry
- Throughout the course, you will perform a variety of different experiments
- You need to be aware of the hazards and risks that accompany practical work and be able to suggest ways to minimise these risks
- Risks may be chemical or environmental
- Environmental risks arise due to the potential harm that the materials used and the products formed can have on our environment
- Some investigations may have ethical implications
Hazards & Risks
- The hazard of a chemical substance relates to the inherent properties of the substance
- The risk is associated with how you plan to use it, the chance of it causing harm and the severity of the harm that it can cause
- Take hydrochloric acid as an example:
- The hazard associated with hydrochloric acid depends on its concentration:
- Concentrated HCl is classified as corrosive
- Mildy concentrated HCl is classified as an irritant
- Dilute HCl is not classified as hazardous
- The risk associated with using hydrochloric acid depends on
- How much HCl you use
- How you use it
- For example, if you pour HCl into a burette above eye level, it is more likely to get into your eyes than if you fill the burette below eye level
- For example, if you pour HCl into a burette above eye level, it is more likely to get into your eyes than if you fill the burette below eye level
- The risk of harm can be reduced by how we use the acid, for example:
- Hydrochloric acid could potentially cause harm to your eyes
- This risk of this, however, depends on how likely it is the acid will get in your eyes
- We can reduce this risk by using eye protection
- Note: Using eye protection does not affect the hazard, but does decrease the risk of harm
- The hazard associated with hydrochloric acid depends on its concentration:
Hazard warning symbols
- Hazard warning symbols are standardised symbols used on labels and safety data sheets to communicate the hazards associated with a chemical
- There are nine hazard warning symbols, each representing a different type of hazard
- These symbols are usually depicted inside a red diamond with a white background
Table showing the most common hazard symbols
| Hazard Symbol | Meaning | |
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Health hazard | includes warning on skin rashes, eye damage and ingestion |
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Corrosive | can cause skin burns and permanent eye damage |
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Flammable | can catch fire if heated or comes into contact with a flame |
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Acute toxicity | can cause life-threatening effects, even in small quantities |
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Hazardous to the environment | substances that are a threat to aquatic life and the environment |
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Oxidising | oxidising agents that can cause fire or explosions |
Risk Assessments
- Risk assessments can be used to help reduce the risk of certain hazards in a laboratory
- To carry out a risk assessment, the following steps are taken:
Identify the hazards:
- Write a list of all of the chemicals used and identify those substances which have potential hazards associated with them
Assess the risks:
- Evaluate the likelihood and severity of harm resulting from exposure to the identified hazards
- Factors to consider include:
- The amount used
- The age and experience of the person using it
- Whether it will be heated
- The type of product given off, e.g. is it a gas that could be inhaled?
- You can categorise risks into low, medium, or high levels
Implement control measures:
- Develop control measures to reduce the risks to an acceptable level, e.g.:
- Elimination, e.g. completely remove the hazard
- Substitution, e.g. replace a hazardous chemical with a less hazardous one
- Use of good laboratory practices, e.g.
- Keeping a cap on a bottle after removing some of the substance
- Keeping the substance away from a source of heat
- Use safety equipment, e.g. use of fume hoods to prevent the inhalation of toxic gases
- Use of Personal Protective Equipment (PPE), e.g. use gloves when handling concentrated acids to protect skin from exposure if spilt
- Plan for an emergency, e.g. what to do if some of the substance is spilt on the floor or gets on the skin
- Material safety data sheets (MSDS) are available to help carry out risk assessments when using chemicals and provide information on the safe handling and use of chemicals
Examiner Tip
When you are planning a practical procedure for internal assessment and you are suggesting a safety precaution you need to say more than just 'wear a lab coat and goggles'.
This is standard practice in any laboratory. You need to identify what the hazard is, and to justify the safety precaution taken e.g.
'HCl gas is produced which is toxic and corrosive, so this step needs to be carried out in a fume cupboard'
Proper Handling and Storage of Chemicals:
- You should always look at the material safety data sheets (MSDS) when handling or storing chemicals
- Make sure that you label any pieces of equipment that you use to handle chemicals
- For example, when preparing a standard solution for use in titrations, ensure that the volumetric flask used to prepare the solution is properly labelled with the identity and concentration of the solution, together with any necessary hazard symbols
Environmental Impact Assessment
- You need to consider the potential environmental impact of your investigation
- Make sure that any waste is disposed of correctly, including any unused reactants or products formed during the course of the investigation
- You should consider whether there are any alternative methods or Green Chemistry approaches that are more environmentally friendly and reduce the use of hazardous substances
The 12 Principles of Green Chemistry
The 12 Principles of Green Chemistry guide chemists in designing chemical processes that are more sustainable, environmentally friendly, and socially responsible
- Applications of these 12 Principles of Green Chemistry are beneficial to the environment and can be incorporated into laboratory work by:
- Reducing the volumes and concentrations of reagents
- Minimise waste by the use of micro-scale laboratory work and the reuse of excess reactants and products
- Choose solvents carefully and use aqueous solutions or simple alcohols/alkanes wherever possible
- Use a catalyst where possible to minimise waste and energy consumption
- For more information about the environmental impact of using a catalyst, see our revision notes on Energy Profiles With & Without Catalysts
- Determine the atom economy and look at ways to increase this
- For more information about atom economy, see our revision notes on Atom Economy
Ethical Considerations
- Ethical implications are not so obvious in chemistry investigations but still need to be considered
- For example, if an investigation involves human subjects, consent from the participants needs to be obtained
- For investigations involving animal testing, ethical guidelines and protocols for animal experimentation must be followed
