Life science includes branches of science, such as biology, ecology and medicine that deal with living organisms and their organization, life processes, and relationships to each other and their environment.
A. Animal Care:
The use of animals in the science classroom can be a very rewarding educational experience. Investigate and follow local board of education policy relative to care and use of animals in the classroom and laboratory in your school district. With animals comes humane care and appropriate animal husbandry practices. Abuse, mistreatment and neglect of animals are unacceptable. The following safety precautions should be addressed when dealing with animals in the laboratory:
- Provide adequately sized cages.
- Make sure cages are cleaned on a regular schedule.
- Cages should be locked and in an environmentally comfortable location.
- Check with the nurse for student allergies and make accommodations as needed.
- Use gloves when handling vertebrates.
- Always wash hands with soap and water after handling animals in the laboratory.
- Immediately report and have medical examination of animal bites.
- Should an animal die unexpectedly, a veterinarian should be contacted to evaluate the animal.
- Never have poisonous animals in the laboratory.
- Only secure animals from reputable suppliers.
- Dispose of animal waste and cage materials in a hygienic manner.
Safety issues relative to visiting animals should also be addressed. Make sure the visiting animal has had all appropriate immunizations and is from a reputable source like Audubon Society and other credible groups. Also review behavioral expectations, care and safety protocols with the animal caretaker in advance of the visit.
Biotechnology is an exciting relatively new area for course work in middle schools and is becoming more popular. The following procedures for working with biotechnology foster a safer learning experience:
- DNA and microbes should be handled as if they can cause infections.
- Handwashing hygiene is required before and after laboratory work by washing with antibacterial soap and water.
- Gloves, chemical splash goggles and aprons are required.
- Keep fingers away from eyes, nose and mouth.
- Decontaminate work surfaces before and after laboratory activities and accidental spills.
- Use only mechanical pipetting. Never use mouth pipetting techniques.
- Decontaminate all labware such as glassware that was used in laboratory work by soaking in a 10 percent bleach solution for several hours.
- Prior to disposal of biologicals, destroy all experimental microorganisms.
C. Bloodborne Pathogens and OPIMs:
Bloodborne pathogens are bacteria, viruses and parasites found in human blood and other body fluids (Other Potentially Infectious Materials, or OPIMs). They can infect and cause disease in humans. The two pathogens recently receiving the greatest attention are the hepatitis B virus (HBV) and human immunodeficiency virus (HIV). Other pathogens that can also be of concern are herpes, meningitis, tuberculosis, Epstein-Barr virus, Lyme disease, malaria and syphilis, to name a few.
Other potentially infectious materials, or OPIMs, can also foster disease. OPIMs include human body fluids such as semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid, peritoneal fluid, amniotic fluid, saliva and any other body fluid that is visibly contaminated with blood.
Bloodborne pathogens can be transferred by four different ways — direct, indirect, airborne and vector-borne. Direct and indirect are the biggest threat:
Direct — by touching body fluids from an infected person. This includes contact with lesions, open wounds or sores on the skin. Skin lining of the mouth, nose or throat, and eye contact/invasion, are additional avenues.
Indirect — by touching objects that have touched the blood or another body fluid of an infected person.
Allowing students to do blood work is not a prudent laboratory practice, given the risks involved. The Centers for Disease Control, OSHA and other regulatory agencies have clear prudent practices for this purpose.
Based on the means of transmission, life-threatening implications and an individual's right to confidentiality, the potential for bloodborne pathogen infection raises several issues for science teachers in laboratory situations. Although OSHA protects employees and not students, students involved in blood work create an unsafe working environment for employees. The OSHA Bloodborne Pathogen Standard states (29 CFR 1910.1030(d)(1): "Universal precautions shall be observed to prevent contact with blood or other potentially infectious materials." Teachers as employees can just as easily be exposed to bloodborne pathogens from students as they can from other employees. Bloodborne pathogens don't discriminate!
OSHA's Bloodborne Pathogens Standard addresses the blood hazards in the workplace. This standard covers all employees who can "reasonably be anticipated" to have contact with blood and other potentially infectious materials. Science teachers certainly fall under this category and are therefore covered under the bloodborne pathogens standard.
Science teachers, supervisors and their employers need to secure safe alternatives to laboratory activities such as human blood typing, cheek cell sampling and urinalysis.
Investigate and follow local board of education policies dealing with dissections. Should plant or animal dissections be used in a class for a laboratory or demonstration, the following safety precautions should be observed:
- Share the MSDS information with students on the preservative prior to doing any dissection activity.
- Contact the school nurse to determine if any students have allergies relative to specimen preparation chemicals.
- Always used chemical splash goggles, gloves and aprons when doing dissection work.
- Review emergency eye-wash procedures for chemical exposure prior to doing dissection work.
- Always have the specimen completely rinsed prior to dissection to avoid contact with preservative chemicals.
- Mount specimens on a dissecting pan in lieu of holding the specimen.
- Use sharps such as dissection scalpels and blades with caution.
- Cut away from the body — never toward the body.
- Never remove any dissected parts from the laboratory.
- Discard dissected parts in appropriate and labeled waste containers.
- Always wash hands with soap and water after completing the dissection and cleanup.
Electrophoresis is a great opportunity for the laboratory study of DNA sequencing and more. This activity is becoming more popular with the advent of biotechnology studies at the middle school level. However, electrophoresis units tend to operate at relatively high voltages. The following general safety procedures need to be addressed in dealing with this technology:
- Avoid physical contact to unintentional grounding points and conductors like metal, water sources and jewelry.
- Work should be located on nonconducting benches and floors. Rubber mats can serve as an insulating surface.
- Use only ground-fault circuit interrupt (GFCI) protected electrical receptacles for power.
- Locate the equipment in places where wires will not cause a trip and fall hazard.
- Prior to use of equipment, inspect and correct items such as cracks, leaks and frayed wires.
- Use caution making any physical contact with the apparatus. A thin layer of moisture acts as an electrical conductor.
- Some electrophoresis devices have cooling components or apparatus. Do not contact any cooling apparatus with a gel as the tubing can be a current conductor. Always directly supervise the use of the equipment.
- Exercise caution in working with power supplies that produce high voltage surges when first energized. Should the electrophoresis buffer spill or leak, stop the operation and clean up the spill immediately.
- Use and post appropriate "Danger – High Voltage" warning signage on power supply and buffer tanks.
- Upon completion of work, always wait 15 seconds for capacitor discharge after shutting off the power supply before making any disconnections or connections.
F. Field Activities:
Field experiences in biology classes help provide applications to classroom curriculum studies. In preparing for a field experience, the following safety preparations and precautions should be taken:
- In planning for field work, review board of education field trip policies.
- Secure information from parents and the school nurse relative to student medical needs, allergies and contact information.
- Written permission to obtain help for special needs should also be secured in advance.
- If laboratory chemicals are used during the field work, MSDS sheets are required on the trip.
- Communications are essential during field work. Bring a cell phone or two way long range radio to keep in touch with the school.
- West Nile virus, Lyme disease and other insect-borne diseases are real threats. Use appropriate dress (long sleeve shirts, pants, closed-toe shoes or sneakers) and repellents for insects. Make sure that you've informed parents in advance about the use of repellents, so that potential allergies can be avoided.
- Have a behavior contract that everyone understands, with consequences that everyone will support.
- Use chemical splash goggles and gloves when working in the field with river, pond or lake water, water testing chemicals and any other materials/activities that may prove hazardous to the eyes.
- Use good sun sense by having students and teacher wear long sleeves, long pants, large-brimmed hats, sunglasses and sunscreen (SPF 30 minimum).
G. Heat Sources:
- Autoclaves/Pressure Cookers
Autoclaves can be dangerous given high pressures and temperatures. Only science teachers or trained science paraprofessionals should operate these devices. Apply the following safety precautions when using autoclaves:
- Inspect the autoclave door and gaskets to make sure they are firmly locked in place.
- Post signage on autoclave warning of "hot surfaces, keep away."
- Never place combustible or flammable materials near or on the autoclave.
- Wear heat-resistant gloves, apron and chemical splash goggles.
- Do not leave the autoclave unattended during operation.
- Shut down the autoclave should there be any indication of a leak.
Pressure cookers are less expensive than autoclaves and may be useful in simple laboratory sterilization procedures. They can be equally as dangerous as autoclaves at high pressures and temperatures. Their use is not advocated given the potential for explosion in the case of faulty pressure release values. However, if pressure cookers are to be used, follow these safety tips:
- Older pressure cookers have fewer safety features and have the potential to explode if not operating correctly. Always inspect the device to make sure clamps are securely attached, the gasket seal is in place, and the vent tube is clear.
- Make sure the vent tube is clear and operational.
- Never touch the cooker until it is cooled down.
- Never leave the cooker unattended during operation.
- Bunsen Burners
Bunsen burners can be dangerous as a heat source, given their hot flame. The use of hot plates can be safer and is preferred at the middle school level. Use the following safety hints for a safer operation if gas burners are used:
- Make sure hair is tied back.
- Always wear chemical splash goggles.
- Light the burner at arms length using an igniter or splint.
- Do not operate the burner with acrylic nails.
- Never leave the burner unattended.
- Do not touch the burner until it has had time to cool off.
- Do not operate the burner while igniting it.
- Hot Plates
Hot plates are a major heat source in biology laboratories. They are easy to operate and less dangerous than gas burners.
- Always inspect wiring on hot plates before use. Make sure insulation is in place and all prongs are on the plug.
- Plug the hot plate into a GFCI protected wall receptacle.
- Never touch a hot plate that has been in operation until it cools.
- Never tie the cord around a heated hot plate.
- Never leave a hot plate unattended.
Microbe study in the laboratory requires special precautions given the opportunity of pathogenic bacteria exposure. This is especially true today with the ever increasing number of immune-challenged students and antibiotic-resistant strains of bacteria. Bacterial cultures should only be done as teacher demonstration at the middle school level with safe bacteria sources, such as live yogurt and kefir cultures. Commercially prepared preserved bacteria slides are also a safer alternative to live cultures. However, students can be involved in activities reflecting the presence and activities of bacteria. There are a number of laboratory test strips available from biological supply houses and pharmacies that can be used to detect the by products of bacterial action. An additional alternative is the use of yeast cultures for student use.
The following safety protocols should be strictly enforced with any bacterial work:
- Personal protective equipment such as chemical splash goggles, lab coat or apron, and gloves are required during the laboratory activity.
- Make sure all skin scratches and cuts are covered with bandages.
- Before and after laboratory activities, wash the work area with disinfectant.
- Absolutely no food or drink is allowed in the laboratory.
- Keep sources of potential contamination such as pencils, hands and laboratory equipment away from body orifices such as mouth, ears and nose to prevent potential contamination.
- Have disinfectant tray available for the discard of contaminated equipment such as pipettes, petri dishes and more.
- Should there be an accidental spill of microbial organisms, immediately contain it with dry paper towels. Sterilize the paper towels and disinfect the area of the spill.
- No general survey collections should be cultured given the danger of pathogenic organisms. An effective alternative can be commercially prepared slides.
- All bacteria cultures and petri plates should be autoclaved or microwaved prior to disposal.
- Wash hands with antibacterial soap and water after completing the laboratory work and cleaning up.
Microwave ovens can be used as both a heating source and decontamination device. Simple safety precautions include the following:
- Never operate the microwave oven when empty.
- Always check the door seal prior to use to make sure it does not have a breach.
- Persons with pacemakers should not be near the oven when operating.
- Never place metal objects such as aluminum foil in the oven.
- Do not put face near the oven door while operation.
- Make sure the inside surface of the microwave is clean.
- Post proper signage warning of microwave use.
The study of plants is both interesting and relevant to everyday life from food sources, oxygen production and energy sources. However, plants can also produce toxic substances that can put human life in harm's way. Be certain to follow the following safety plan when dealing with plants in the laboratory:
- Check with the school nurse for potential allergy issues for students. Make accommodations as necessary.
- Wear safety splash goggles, gloves and aprons when working with plants.
- Never have poisonous plants or plants producing allergens in the laboratory.
- Inform about the difference between edible and nonedible plants
- No plant part should be tasted without specific direction from the teacher.
- No parts of plants should be burned that have allergen-type oils such as poison ivy and poison oak.
- Wash hands with soap and water after working with plants.
The Connecticut Department of Environmental Protection has made the following statement about non-native plants in its non-native invasive plant species policy:
Many non-native plants have been introduced intentionally or accidentally, with most having no deleterious effects on agricultural lands, waterways, wetlands, or conservation areas. Some non-native plants, however, exhibit an aggressive growth habit and can out-compete and displace native species. These are referred to as invasive. Invasive plants, also called harmful or noxious weeds, are a serious problem in Connecticut and elsewhere, reducing agricultural production, impairing recreation, and causing the loss of biological diversity.
The Connecticut DEEP maintains a list of non-native invasive plant species. Before plant species are selected for use in the lab, check out the list of non-native invasive plant species before placing specimens out in the field.
- Never store food in any refrigerator or freezer used to store chemicals.
- Refrigerators and freezers should be cleaned out on a regular basis.
- Containers placed in a refrigerator or freezer should be completely sealed or capped, securely placed and labeled.
- Avoid capping materials with aluminum foil, corks and glass stoppers.
- All liquid chemicals should be stored in plastic trays.
- All specimens should be stored in plastic bags with labels.
- All items stored are to be appropriately labeled.
- Review inventory on refrigerator/freezer contents to ensure compatibility of the contents.
- Store only chemicals in amounts needed over a reasonable amount of time. Each chemical has a shelf-life and decomposition products that could be hazardous.
- Remember that power outages and technology failure can have an impact on stored contents. Be aware of unusual odors or vapors.
- Do not use glass beakers as lids for bottles.
- Do not stack materials too high.
- Do not use graduated cylinders or volumetric flasks to store materials.
- Refrigerators/freezers should be periodically inspected (i.e., at least monthly).
- Post an up-to-date inventory on the refrigerator door.
- If potentially infectious material is spilled, clean immediately with a disinfectant agent such as 70 percent isopropyl alcohol. Then, wipe down the area with soap and water.
- The refrigerator/freezer must be properly grounded and a permanent installation (i.e., no extension cords).
- The refrigerator/freezer must be located away from lab exits.