Issues Relating to Dissections
Background
Either fresh, frozen, freeze-dried or preserved specimens of plants and animals may be used for dissection activities, provided they comply with the ethical guidelines and policies of the school authority. Plant dissection activities should not include any plant material that is allergenic or toxic. Pollen allergies should be considered when dissecting flowers. It is important that animal dissection material does not contain any pathogens that could spread disease to staff and students. All animal dissection material should be obtained from a reputable source, either a supplier of food for human consumption (e.g. butcher, food outlet) or from a biological supplier.
A risk assessment of each dissection activity should be performed and should take into account such factors as skill level and behaviour of students, class size, available facilities, allergies, chemical sensitivities, and the level of training and experience of staff. This includes taking into consideration that students might feel ill or faint during dissections, feel squeamish, or have ethical views preventing them from participating in such activities. Staff should have a first aid plan for students who faint or cut themselves.
No parts of specimens should be consumed or removed by students. No food or drink should be consumed during the dissection or stored in a refrigerator containing dissection material.
Some possible ways to reduce risks
Risks may be minimised as follows:
- The workplace for a dissection activity should be well-organised, well-ventilated, well-lit and clean. Ergonomics should be considered and excess furniture removed. The dissection material should always be fastened to a dissection board/tray, rather than be held by a person. It is recommended that dissection activities are not conducted on students’ desks, but should be performed on the laboratory benches. Water and soap should be readily available in the room.
- Students should be warned about the possibility of blood and/or odours during animal dissections. It is useful for staff to demonstrate the dissection to the students before the students start on the dissection activity, thereby showing them the correct procedure and also preparing the students for the appearance and odours of the dissection material.
- Students should be trained in the use of sharp instruments, prior to use. This includes discussing with students the need for always cutting away from oneself and any other person nearby. Also, training should include the safe arrangement of scalpels, pins, scissors, etc at designated locations in the workspace to minimise accidental cuts or knocking instruments or dissection material off the bench.
- Scalpel blades should only be attached and removed by school staff, due to the possibility of serious injury. Staff should be trained in the safe attachment and removal of scalpel blades. Only the compatible blade size and handle should be used. Alternatively, disposable scalpels should be used.
- Depending on the dissection activity, appropriate personal protective equipment, such as gloves, aprons, goggles, etc, should be worn. An eye-wash should be available. Contact lenses should be avoided, since preservative fumes may be trapped behind the lenses and cause irritation of the eyes. Instead, prescription glasses with safety glasses on top should be worn. Possible microbial aerosols and unpleasant odours may be released if the stomach or the intestines of freshly-killed or recently-frozen animals are cut.
- Staff should check with students about any chemical sensitivities or allergies to any dissection material or to any component of the preservative fluid, prior to the dissection activity. Specimens preserved in formaldehyde should be avoided, as formaldehyde is a carcinogen and skin sensitiser. Specimens preserved in formalin should similarly be avoided. Ethylene-glycol-preserved specimens are originally fixed in formaldehyde solution (formalin), but this is washed away prior to the specimens being preserved in ethylene-glycol and are therefore much safer to use than those containing formaldehyde or formalin. It is important to check the Safety Data Sheet (SDS) to see which preservatives have been used. Gluteraldehyde, sometimes added to preservative fluid, is toxic and a respiratory/skin sensitiser. Preserved specimens should be washed under running water immediately after taking the specimen out of the preservative liquid and prior to dissection. Care should also be taken to ensure that there is no ignition source nearby, if the preservative contains a flammable liquid such as ethanol or isopropanol.
- All fresh dissection material should be used or frozen within 24 hours of purchase. Frozen animals should be defrosted overnight in a refrigerator prior to the dissection activity and used within 24 hours or disposed of appropriately.
- Scrupulous hygiene should be used. All cuts or broken skin of students and staff should be covered by water-resistant dressings and gloves before class. Students should be advised to keep their hands away from their mouths, noses, eyes and faces during and after the dissection activity. Students and staff should wash their hands thoroughly with soap and water and dry their hands properly before leaving the laboratory. The minimum of items (such as books, pens, pencil cases, laptops, mobile phones, paperwork and backpacks) should be in the vicinity of the dissection activity.
- Dissection waste should be disposed of appropriately in the industrial bin (wrapped in newspaper and double bagged, along with contaminated gloves, disposable aprons, foam trays etc) and all contaminated instruments and surfaces washed and/or disinfected as required. A check should be performed to ensure all instruments are returned and not removed by any of the students.