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IX. Biology and Environmental Science
Biology and Environmental Science
teachers and their students face a wide range of potential hazards. In
addition to chemical reagents, there are the hazards associated with the
handling of organisms, classroom activities on the school grounds and outdoor
study areas, and the containment of biological specimens. Effective control
of such hazards involves both the recognition of each hazard and the
development of control procedures. Every student and teacher should
be protected by safety devices when experiments are being conducted in the
biology laboratory. •See Chapter IV, Personal
Safety Provisions. 1. Body and Clothing
Protection •See
Chapter IV.C, Protective Apparel. 2. Eye Protection See
Chapter III.D, Safety Equipment; Chapter IV.A., Eye
Protection Concerns; Chapter VI.J, Cryogenics; and Chapter VIII.B.2.a, At the
Site - Goggles. 3. Hand Protection ·
Rubber or plastic gloves should be provided for students to
use when handling preserved organisms. ·
Anyone with breaks in the skin or unhealed scratches should
wear rubber or plastic gloves when working with preserved organisms. ·
Heavy rubber or leather gloves should be provided for use when
handling live animals as protection against animal bites and scratches.
·
Soap and water should be available for student use. Students
should be required to wash their hands before and after laboratory
experiments that involve the handling of live or dead organisms. •See
Chapter IV.C.2, Protective Apparel - Gloves. 1. Respiratory
Protection •See
Chapter III.E, Ventilation, and Chapter IV.C.4, Respiratory Protection.
B. Classroom/Laboratory Safety 1. Equipment •See
Chapter VI, Safe Handling of Equipment. 2. Chemical Reagents a. Stains Staining
is an important part of biology studies. Teachers must obtain the appropriate
Material Safety Data Sheets (MSDSs) for all staining reagents and follow the
stated precautions. •See
Appendix C, MSDS: Explanation and Samples. b. Drug-Related
Items The
following substances commonly used in the biology program have special
security needs because of their potential abuse. They should be kept in a
secure area and used with caution:
•See
Chapter VII. Chemicals: Managing, Handling and Disposing. 3. Dissections a. Students should
wear chemical splash safety goggles and aprons. b. Long hair, loose
clothing, and jewelry should be secured. c. Rubber or plastic
gloves should be provided. d. Students with
breaks in the skin should wear gloves or be excused from laboratory. e. The room should
be adequately ventilated during dissections, particularly when preserved
specimens are used. f. Care should be
used in the handling of all dissection instruments. g. Dissecting pans
or trays should be provided. h. Scalpels or
single-edged razor blades should be used. Single-edge razor blades with a
rigid, reinforced back are preferred. i. Students should
be instructed to cut away from the body and to cut down against the
dissecting pan or tray. Care must be taken to keep the hand that is not holding
the cutting instrument away from the cutting edge. j. It is important
to secure the specimen in or to the pan or tray. Dissection pans may be used. See Chapter IX.D.2.d, Zoology: Animal
Considerations--Dissection. 4. Heating and
Sterilization Devices a. Autoclaves/Dry
Heat Sterilizers/Pressure Cookers. Autoclaves and dry heat
sterilizers are preferred. All precautions in dealing with electrical
equipment should be followed. A pressure cooker may be used as a substitute,
but it involves greater attention due to the hazards involved in a
non-automated system. Note: Most plastic containers and equipment,
such as plastic petri dishes, are not autoclavable.
Autoclaves,
heat sterilizers, and pressure cookers should be run only by the teacher or
professional aide or by the student aide if he/she is under the direct
supervision of the teacher or professional aide. The teacher, professional
aide, and student aide should be knowledgeable
about the operating instructions of the pressure cooker, autoclave, or heat
sterilizer. In
using a pressure cooker, check the safety valve before pressure is built up.
Final gauge pressure must not exceed 15 pounds per square inch. The equipment
should be turned off and allowed to cool before the stopcock is opened to
equalize pressure. Dry the pressure cooker before storing because aluminum
will oxidize if stored wet, and pits produced from
the oxidation may weaken the metal when under high pressure. Heat sterilizers
are preferred over pressure cookers. •See
Chapter XI.B, Electrical Hazards, and Chapter IX.C.4, Decontamination and
Disposal of Materials. b. Gas burners. When heating
materials at high temperatures, a gas burner may be used. •See
Chapter VI.D.1, Safety Rules for Using Gas Burners. c. Hot plates. See Chapter VI.D.2, Safety Rules for Using
Electric Hot Plates. d. Water baths. Water baths can
be useful in a biology laboratory. The baths must be well maintained for safe
operation. e. Incubators. Incubators may be
useful components of a biology laboratory. Care should be taken to keep
incubators safe and well maintained. They should be cleaned out regularly to
prevent unwanted growth of organisms. Students should be instructed on their
proper use. f. Microwave Ovens. Microwave ovens may
be useful in the biology laboratory, especially in biotechnology experiments
where agar must be heated to pour gels. Microwave ovens should be safely
located and appropriately maintained. Students should be instructed on their
proper use. Students with pacemakers should not work in the proximity of a
microwave oven. 5. Microscope Work a. Microscopes ·
Students should be instructed in the proper use of the
microscope. ·
All precautions in dealing with electrical equipment should be
followed. ·
If microscopes with reflecting mirrors are used for
illumination, care must be taken to prevent using direct sunlight as the
illumination source. ·
Students with eye infections should not be allowed to
contaminate the eyepiece(s) of the microscope. a. Microtomes A microtome
may be a useful tool, especially in upper-level biology classes. Students
must be instructed in the proper use of the microtomes, which contain
extremely sharp knife blades. See Chapter XI.B, Electrical Hazards. 6. Refrigerators and
Freezers •See
Chapter VI.E, Refrigerators and Freezers. This section pertains primarily to
the use of viruses, bacteria, and other microscopic organisms. Bloodborne pathogens require special considerations. The
handling of these pathogens is treated in 29CFR 1910.1030. This publication
covers definitions, exposure control, specific procedures and protocols to
comply with the regulations, precautions for specific pathogens, signs,
labels, training, and record keeping. Proper laboratory technique is the basis
for all cautions in this section. •See Chapter IX.D,
Zoology: Animal Considerations, and F, Biotechnology and Recombinant DNA
Research. 1. Materials and
Specimens a. Known pathogens
should never be used in the classroom. b. Specimens should be
obtained from reliable supply companies or other sources that can validate
species or strains. Most supply company catalogs indicate which organisms are
pathogens and which are not.
i.
A list of sources is available in the National Science
Teachers Association annual publication, NSTA Science Education Suppliers. The
following website offers more information on this topic:
ii.
Other sources may include local research facilities, e.g.,
universities or hospitals. The American Type Culture Collection, a nonprofit
organization, maintains an extensive collection of microbiological specimens
that may be purchased. This source is especially useful for obtaining
materials not available through other suppliers. The
following website offers more information on this topic:
iii.
Specimens should be requested for shipment when needed and not
stored for long periods of time. c. All
microorganisms should be handled as if they were pathogens. d. Proper aseptic
techniques should be used at all times when working with bacterial, viral, or
microbial cultures. e. Microorganisms
cultured directly from the environment should not be incubated for cell
cultures as incubation could promote the growth of pathogenic organisms. f. Humans and/or
human products should not be used as a source of bacterial/microbial culture
material in most cases. In special circumstances (e.g., AP Biology), teachers
should obtain the supervisor’s permission and follow the Universal
Precautions. The
following website offers more information on this topic: g. Blood agar, serum
agar, and/or chocolate agar should be avoided for use in classroom
experimentation. h. Staining reagents
may be purchased through supply companies. •See
Chapter IX.B.2.a, Stains, and IX.F.2, Staining DNA. 2. Equipment Essential
equipment for working with microorganisms includes: a. Sterilization
equipment (autoclave, heat sterilizer, or pressure cooker) for media
preparation, sterilization of glassware and equipment, and decontamination of
disposable material b. Sterile transfer
equipment (micropipetters with disposable tips or
sterile pipets) for safe transfer of microorganisms c. Adequate work
space and equipment to prepare media d. Proper storage
facilities, including refrigeration and incubation equipment e. Supplies for
cleaning up and disinfecting work areas f. Pipets Due to
the nature of microorganisms, the use of disposable pipets, pipet tips,
dishes and culture plates, etc. is recommended. If you use nondisposable glassware, take care to properly
decontaminate it. •See
Chapter VI.A, Glassware. g. Special trash
containers for all cultures for proper sterilization and disposal There
should be separate containers for disposal of glass, plastic, paper, etc. All
trash receptacles should be clearly identified. h. Petri dishes for
use with noninfectious materials ·
Use sterile plastic Petri dishes only once. After using them, tape the dishes shut, place them in a bag, and
dispose of them in an incinerator or the trash according to recommended
disposal guidelines. ·
Glass petri dishes should be sterilized before use. After use,
dispose of the culture medium in a sealed container and soak the dishes in
strong disinfectant. Wash them in detergent and autoclave. •See
Chapter IX.C.4, Decontamination and Disposal of Materials. 1. Procedures and
Sterile Techniques a. Keep the
laboratory clean. b. Disinfect the
work area before and after each laboratory procedure. Use of a commercial
disinfectant to wipe down the area is acceptable. c. Students should
use gloves, chemical splash safety goggles, and aprons as the teacher deems
necessary. d. Do not leave
laboratory materials unattended. e. Inoculating loops
i.
Inoculating loops should be flamed before and after the
transfer of microorganisms and a final time before storing.
ii.
The inoculating loop should be used with a steady hand and should
not be used for stirring, as splashing may occur.
iii.
When transferring the inoculant, do not use a hot loop, which
can cause spattering of the culture medium and thereby create aerosols of the
culture organisms. (Make sure the loop is cool by touching the loop to an
area of the sterile agar that will not be used or allowing the loop to air
cool for a few seconds.) a. When a liquid
culture medium is used, the liquid should never be allowed to come in contact
with the stopper used to seal the culture medium. Care should be taken to
avoid spattering when the stopper is removed. b. Forceps should be
used to handle slides, and slides should be flamed with care to avoid burns
and shattered slides. c. Cultures should
be incubated at temperatures no higher than 25 C to decrease the possible
growth of pathogens. d. Pipetting of
bacteria
i.
Use a micropipet or disposable pipet
and a pipetter or pipet bulb. Micropipetters
are preferred for transfers of small amounts of liquid inoculant. A
disposable pipet is preferred for larger amounts.
ii.
Used glass pipets should be immersed in disinfectant and then
autoclaved. Do not allow students to aspirate or to spray bacterial/microbial
cultures, which can create a serious biological hazard. Never allow mouth
pipetting.
iii.
Colonies should be counted on closed Petri dishes or plates. Parafilm is recommended for sealing culture plates.
iv.
Any demonstration plates passed around the class must be
sealed with parafilm or tape.
v.
An autoclave, heat sterilizer, or pressure cooker should be
available. •See
Chapter IX.B.4.a, Heating and Sterilization Devices – Autoclaves/ Dry Heat
Sterilizers/Pressure Cookers. See also Chapter VI.G, Pipets, and
Chapter VI.I, Centrifuges. 2. Decontamination
and Disposal of Materials Disposal
of scientific materials such as reagents is an issue in every science
classroom and laboratory. In biology, it is necessary to differentiate
between infectious and noninfectious materials. a. Noninfectious
materials include materials such as chemical reagents, household
substances, and biological samples free of parasites or contagious pathogens.
These are substances that carry no “communicable” hazard. Noninfectious
biological waste should be treated with sound safety management techniques.
To dispose of these materials, place them in double domestic plastic trash
bags secured by metal wire twists. The bagged wastes may then be placed in
domestic trash receptacles to be disposed of in an approved landfill in
accordance with state and local regulations. •See
Chapter VII.C.3, Disposing of Waste. b. Infectious
materials (or biological waste or biohazardous
waste) are communicable biological materials. These materials include
contagious microorganisms or parts of microorganisms (including bacteria,
viruses, or DNA fragments) as well as disposable biological equipment that
has been exposed to infectious materials. Infectious
biological materials require decontamination prior to disposal through one of
the following methods.
i.
Incineration on-site. This approach is the preferred process.
This method renders the waste noninfectious and, at the same time, changes
the shape and form of the waste. Schools that have incinerators must comply
with all applicable environmental regulations regarding air quality and air
emissions. The next method is emphasized here because most schools do not
have on-site incineration.
ii.
Decontamination. Infectious materials may be rendered
noninfectious by decontamination (sterilization) prior to disposal. Below are
the methods of decontamination most commonly practiced in high schools. ·
Steam sterilization in an autoclave at a pressure of
approximately 15 psi and a temperature of 121° C (250° F) for at least 15
minutes will destroy microbial life, including high numbers of microbial
spores. ·
Dry heat sterilization may be used. However, this method
requires temperatures of 160-170°C (320-338°F) for 2-4 hours. Note:
In both cases, the
autoclaves should be calibrated for temperature and pressure and monitored
with a biological indicator, such as Bacillus stearothermophilus
spores, to ensure effectiveness of the sterilization. It is important that
the steam and heat contact the biological agent. Therefore, bottles
containing a liquid material should have loosened caps or cotton plug caps to
allow for steam and heat exchange within the bottle. Biohazard bags
containing waste should be tied loosely. It is recommended that bags of
biohazard waste be affixed with autoclave indicator tape to ensure the
temperature readings are accurate. Once disinfected, wastes can be treated as
noninfectious waste, double bagged in domestic plastic trash/garbage bags and
secured by metal wire-containing twist ties. Treated bags and containers may
then be disposed of in an approved landfill in accordance with state and
local regulations. •See
Chapter VI.M, Sharps. ·
If neither of these sterilization techniques is practical, the
infectious waste may be transported off-site to a qualified medical waste
disposal firm for subsequent treatment and disposal. ·
If none of the above procedures is possible, the infectious
waste may be immersed in household bleach for 6-10 hours. Although chemical
disinfection is not considered completely effective, bleach is
considered effective in wiping down exposed surfaces and equipment. D. Zoology: Animal Considerations 1. Human Non-invasive,
non-stress laboratory activities involving students as experimental subjects
are encouraged. These include physiological measurements such as pulse, blood
pressure, heart rate, breathing rate, hearing, sight, etc. Obviously, every
precaution must be taken to ensure student safety. The
following are examples of safety precautions that should be followed. a. Blood Pressure. When using the
sphygmomanometer to take blood pressure, do not pressurize the cuff higher
than 150 mm Hg. Allow two minutes to pass before re-inflating the cuff when
taking repeat blood pressure measurements on the same individual. This
experiment can cause stress leading to a shock reaction and unconsciousness. b. Respiratory
Experiments. When respiratory experiments are done, remember that
hyperventilation can be dangerous to anyone but particularly to asthmatics,
epileptics, and those who suffer from bronchial conditions. When the
spirometer is used, a clean mouthpiece should be used by every person being
tested. When testing for carbon dioxide, care must be taken not to allow the
test solution (bromothymol blue and calcium
hydroxide) to reach the mouth. This experiment can cause stress leading to a
shock reaction and unconsciousness. c. Stethoscope Use. Disinfect
stethoscope ear pieces after each use. Teach students the proper use of the
stethoscope to avoid potential ear damage. d. Body Fluids and Bloodborne Pathogens
i.
Recommendations. Federal Regulation 29CFR 1910.1030
must be followed. The National Association of Biology Teachers (NABT) makes
the following recommendations regarding the use of human body samples in the
biology classroom or laboratory: The
following website offers more information on this topic: ·
Use safer alternatives to human samples when possible.
Materials that mimic the properties of blood, saliva, and urine may be
purchased. The American Biology Teacher journal is a source of
information on alternatives. The
following website offers more information on this topic: ·
Use samples known to be free of disease. Do not use any
samples of unknown origin. Avoid samples that are not collected at school. ·
Use samples only if all persons in contact with the samples
comply with all applicable Universal Precautions. Additional guidelines are
available from clinical libraries, hospitals, and public health agencies. The
following website offers more information on this topic: ·
In addition to the Universal Precautions, teachers using human
body samples should conform to the following precautions: o Students must be
allowed to collect samples only with the supervision and advice of the
teacher. o Samples must be
handled with plastic or latex gloves, chemical splash safety goggles, and a
laboratory coat or apron. o Students must
always wash their hands after any laboratory activity involving human body
samples.
i.
Basic Precautions. Below is a list of body fluids and
wastes and their possible uses in a high school classroom or laboratory. Teachers
must follow school system policy regarding parental permission and students’
rights to refuse to participate in experiments using body fluids. Teachers
are encouraged to use safer alternatives in place of human samples when
possible. Some of
the materials on the list have been identified by the Centers for Disease
Control (CDC) as requiring the application of the Universal Precautions. All
body fluids and wastes warrant the application of the Universal Precautions.
Recommended precautions and procedures: ·
Treat all body fluids and wastes as infectious because it is
not possible in the high school laboratory to distinguish that which is and
is not infectious. ·
Taking body fluids or wastes for experiments must be on a
voluntary basis. ·
Use sterile techniques to prevent spreading infectious
diseases. •See
Chapter IX.C.4, Decontamination and Disposal of Materials. d. Blood may be used for
blood typing studies and microscopic and physiological analysis. Students
should be encouraged to obtain their blood type from a doctor and to know
their blood type in case of an emergency. e. Cheek Cells may be used for
microscopic analysis and cell comparison studies. f. Feces are rarely used
in biology instruction but materials containing feces are sometimes used in
microbiology and parasitology studies. g. Respiratory Mucus may be used in
studies of the respiratory system. h. Saliva enzymes may be
used in general biology class activities. Cells collected from saliva are
used for microscopic analysis and for obtaining (culturing) oral
microorganisms from tooth tarter. i. Semen samples may be
used for microscopic analysis. j. Urine may be used for
urinalysis or cell culture, which requires the collection of fresh urine. The
following website offers more information on this topic: 1. Nonhuman The
NMSBVI Science Safety Project Committee endorses the National Science
Teachers Association’s Guidelines for Responsible Use of Animals in the
Classroom and the Institute of Laboratory Animal Resources’ principles
regarding the humane study of animals in precollege education. In all cases, teachers
should consult such organizations and agencies as the local Humane Society
and the State Department of Natural Resources before bringing animals into
the classroom. The
following websites offer more information on this topic: a. Invertebrates Invertebrate
animals are often used for observation and learning activities. For example, Drosophila
sp. (the fruit fly), is used in genetics. Anesthetize the organisms
carefully by one of the following methods.
i.
If experiments are done with fruit flies, take care in
quieting them and/or killing them. Using ether in killing jars is not
recommended. If ether is used, it should be discarded within a month of opening.
One commercial substance used as a substitute for ether contains triethylamine (C2H5)3N,
which is flammable, toxic by ingestion, and a severe irritant. Use with care.
Other methods are: placing the fruit flies in a Petri dish, gently covering
them with cotton, and then inverting the dish for examination under the
dissecting microscope; and refrigerating culture jars and placing “chilled”
flies on a Petri dish over ice.
ii.
Anesthetizing kits also may be used. For example, FlyNap® kits containing relatively harmless components
may be purchased from biological supply companies. Any anesthetic should be
used in a properly ventilated room according to the supplier. Teachers should
obtain manuals available from biological suppliers. These manuals are inexpensive
and serve as a complete guide to maintaining and studying the organisms in
the classroom. b. Vertebrates
(Nonhuman)
i.
Do not take vertebrates from the natural environment. Most
municipalities prohibit the removal of vertebrates from the natural environment.
Doing so upsets nature’s balance and may introduce unwanted microorganisms or
diseased animals into the classroom.
ii.
Obtain animals from a certified disease-free source.
iii.
When studying developing chicken embryos, do not use any
embryos that are more than 18 days old.
iv.
Do not work with virus-infected eggs.
v.
Dispose of dead embryos, which may carry pathogenic bacteria. See Chapter IX.C.4, Decontamination and
Disposal of Materials.
vi.
Do not give away or sell any animals, including baby chicks.
vii.
Do not release animals that are not indigenous to the area
into the environment. Release of indigenous animals must be approved by the
State Department of Natural Resources. c. Other Guidelines
for Working with Animals. The NMSBVI Science Safety Project Committee supports
the following additional guidelines for working with animals in ways that
protect students and the animals. Most of these guidelines relate to animals
in the classroom.
i.
Take care to avoid contact between humans and animals when
either of them may be a disease carrier.
ii.
Keep laboratory animals isolated from wild animals.
iii.
Only the student assigned responsibility for animal care
should have direct contact with the animals.
iv.
Maintain a good environment for the animals, with ample food
and water available to them at all times, including weekends and holidays.
Keep cages clean of wastes.
v.
Protect animals during times of pesticide use.
vi.
Sterilize cages and equipment before and after use. Use
household bleach, 2% phenol, or Lysol®. Rinse cage well with water.
vii.
Parental permission must be obtained before allowing a student
to take an animal home.
viii.
The following animals should not be kept in school: ·
venomous reptiles and fish ·
black widow and brown recluse spiders ·
scorpions ·
bees, wasps, hornets, and other stinging insects ·
animals at high risk of carrying rabies ·
wild animals– particularly mammals
i.
The following animals may be kept at school with the noted
cautions: ·
turtles and snakes (possible Salmonella infection) ·
fur-bearing animals (possible cause of allergies) ·
tarantulas ·
parakeets and parrots (possible psittacosis infection)
ii.
Keep aquariums and terrariums clean so that organic materials
do not act as a reservoir for microorganisms. Remove mineral accumulations
with a vinegar solution and rinse. d. Dissection. By their
consistent attitude in working with animals, teachers can encourage students’
understanding of the educational value of dissection while being sensitive to
living things.
i.
Living specimens should be maintained in the laboratory until
used.
ii.
Live animals being used in dissections should be prepared
using an appropriate method by the teacher or by student aides under the
direct supervision of the teacher.
iii.
Specimens such as frogs can be held for several weeks in the
refrigerator.
iv.
Preserved specimens purchased through reputable biological
supply companies are acceptable subjects.
v.
Animals killed on highways and other non-preserved specimens
should not be used.
vi.
Certain specimens, such as fish and squid, may be purchased
from the frozen foods section of a local grocery store.
vii.
Teachers should assess their needs carefully and order only
enough material for a year. Specimens should not be stored from year to year
since deterioration may occur.
viii.
Before use, specimens should be kept in their original
containers and placed in an area not available to students. Decayed preserved
specimens should be discarded properly.
ix.
Preserved specimens should be thoroughly rinsed in running
water before use.
x.
Freeze-dried specimens that have been rehydrated in a dilute
10% alcohol-water solution for 24 hours should be thoroughly rinsed before
use.
xi.
Specimens are normally preserved in an alcohol-based
preservative from the biological supply company. Formalin or formaldehyde should
not be used. Acceptable preservatives used by reputable supply companies
include Caro-Safe™ and “bioperm.” Specimens
retained for further work on succeeding days should be labeled and
refrigerated if possible.
xii.
Animal skins can be protected from insect damage by storing
them in borax or mothballs.
xiii.
While performing dissections, students should wear chemical
splash safety goggles. Gloves and aprons should be available for student use.
xiv.
Students should wash their hands after any dissection
activity.
xv.
All equipment used in dissections should be thoroughly cleaned
after each laboratory session.
xvi.
Students should be given adequate time to clean tools, pans,
and dissecting stations before the end of the laboratory session.
xvii.
If the dissection is to be continued at a later time,
specimens should be placed in plastic bags to prevent dessication
and deterioration. Bags should be clear or clearly labeled.
xviii.
Specimens should be bagged and then discarded in an
appropriate manner. •See
Chapter IX.C.4, Microbiology – Decontamination and Disposal of Materials.
xix.
Chemical preservatives should be discarded according to the
disposal instructions in the MSDS for the substance. At the conclusion of the
laboratory period, everyone must thoroughly wash hands and arms with soap and
water, taking care to clean under the fingernails. •See
Chapter VII.C.3, Chemical Waste Strategies–Disposing of Waste. e. Research
Procedures
i.
Use invertebrates for research when appropriate because of
their variety and the large number of specimens.
ii.
Vertebrates are appropriate in cases where their similarities
to humans are important to the research. Research should be carried out with
qualified adult supervision and the advice of a veterinarian.
iii.
Plants should be used wherever possible for experiments on organisms.
See Chapter IX.E, Botany and Mycology (Fungi). E. Botany and Mycology (Fungi) 1. Facilities and
Equipment a. Facilities
necessary include proper lighting, adequate heat, adequate water, and
adequate nutrients. b. Containers should
be cleaned before and after use. c. Commercial
potting mixtures are recommended over garden soil because they are relatively
sterile. •See
Chapter IX.G, Greenhouse Maintenance and Operation. 2. Cautions a. Allergies. Many people are
allergic to pollen, mold spores, or other plant exudates. When using flowers,
mushrooms, fungi, etc., in the laboratory, adequate ventilation is essential.
Pollen and mold spores should be displayed in closed glass Petri dishes. b. Seeds. Students should
never eat any seeds used in the laboratory. When working with
pesticide-treated seeds, the seeds should first be washed. Students should
wash with soap and water after handling such seeds. c. Thorns/Needles. Many plants have
thorns or needles. These may be very annoying or even dangerous if contact is
made with the skin or eyes. Students should be made aware of the dangers of
handling such plants. d. Toxic Plants. Certain plants
and plant parts (as well as fungi) contain harmful substances. Some are
poisonous upon skin contact (e.g., poison oak or poison ivy). Gloves help to
avoid skin contact. Other plants are poisonous when ingested (e.g.,
foxglove). No plant should be ingested in the biology laboratory.
Students should be made aware of poisonous plants and be able to identify
common poisonous plants. Local health departments or the Poison Control
Center (MPC) are valuable resources for such information. e. Disposal. Exotic plants
should never be released into the environment where they may compete with
local plants. Such a release can result in an imbalance to the natural flora
(and eventually fauna). For example, the kudzu plant and purple loosestrife
have become pests of major proportions. Native
plants normally do not present a problem for the local environment. Such
plants should be discarded in a manner consistent with school policy and
local ordinances. 3. Chromatography a. Chemical splash
safety goggles and aprons should be worn. •See
Chapter IV.A, Eye Protection Concerns. b. Only water baths
or hot plates with water baths (and not open-flame fires) should be used for
chlorophyll extraction. Extraction may also be accomplished by leaving the
plant material in the solvents overnight at room temperature. c. Only Pyrex or
comparable glass tubes should be used. d. Dissolving and
developing solvents give off toxic vapors. They must be stored in closed
containers and the room e. Solvents are
highly flammable and must not be used near an open flame. Avoid skin contact
when spraying the developing solvents. Use a fume hood when appropriate. See above Chapter IX.D.1.d, Zoology: Animal
Considerations–Body Fluids and Bloodborne
Pathogens. F. Biotechnology and Recombinant DNA Research Work with deoxyribonucleic acid
(DNA) is at the core of many of the hands-on activities in molecular biology
and biotechnology that have been introduced into the high school biology
laboratory. The study of the chemical and physical properties of DNA often
involves the spooling, isolation, enzymatic digestion, gel electrophoresis,
and manipulation of bacterial cells to introduce new genetic information.
Many such laboratory activities can be purchased as complete kits that
provide documentation and guidelines helpful to both students and teachers.
These kits are especially recommended for teachers who are not familiar with
standard procedures in research laboratories. Safety, as always, is a crucial
part of any molecular biology experience. Research requiring containment is
prohibited. The following website offers more
information on this topic: All research involving
recombinant DNA technology must be carried out in accordance with the
National Institutes of Health (NIH) guidelines for conducting research using
recombinant molecules and organisms. These guidelines are contained in the
revised NIH Guidelines for Research Involving Recombinant DNA Molecules dated
June 24, 1994 as amended through April 30, 1998. Essential guidelines for
handling any microorganism or DNA molecule in the laboratory are also
contained in the “Standard Microbiological Practice” section of the manual, Biosafety
in Microbiological and Biomedical Laboratories. The guidelines include procedures
for handling chemicals and microorganisms, maintaining a safe workplace, and
disposal (including decontamination) of used materials (including cells). The
manual, published by the U.S. Department of Health and Human Services, is
available online from NIH and CDC. The following website offers more
information on this topic: Escherichia coli (E. coli) is the standard
experimental bacterium. E. coli is a normal resident of the animal
(including human) digestive tract. Many strains of E. coli are known.
A few strains can cause diseases in humans. Strains of E. coli
recommended for laboratory use are engineered so they cannot normally survive
outside the prescribed conditions of the laboratory. Therefore, these strains
pose little risk of causing disease. However, any opportunistic pathogen can cause . problems if appropriate
safety precautions are not taken. It is important, therefore, to adhere
strictly to accepted microbiological practices with all microorganisms. 1. Guidelines The
guidelines below summarize the procedures for working with biotechnology to
ensure that the activities will be performed safely. a. Handle all
microorganisms and DNA carefully. Treat them as if they could cause
infections. b. Do not eat,
drink, or apply cosmetics in the laboratory. Keep fingers and writing
instruments away from your face and mouth. c. Hands should be
washed with soap and water before and after handling microorganisms and
before leaving the laboratory regardless of what materials were used. When
handling microorganisms or other living materials, students who have cuts on
their hands should wear latex or rubber gloves to protect against infection. d. Use only
mechanical pipetting devices for transferring any material. Do not allow
mouth pipetting. e. Perform procedures
carefully to minimize the formation of aerosols. For example, in close
proximity to liquid surfaces or the bottom of empty receiving containers,
pipet tips tend to form aerosols. Do not force the last drop from a pipet. Keep pipet tips away from the face to avoid
inhaling any aerosol that may be formed. f. Decontaminate
work surfaces before and after their use and after a spill. Decontaminating
solutions should be readily available and contained in well identified
laboratory squeeze bottles. g. Discard in appropriately
marked containers all solid and liquid materials that have come in contact
with microorganisms. The containers should be easily accessed by students at
each laboratory station. h. Decontaminate all
liquid and solid wastes that have been in contact with experimental
microorganisms. Destroy experimental microorganisms before disposal. i. Glassware
(including pipet tips and Eppendorf tubes) that has been in contact with
isolated DNA, restriction enzymes, or other non-living materials does not
have to be decontaminated. It should, however, be soaked in a disinfectant
such as a household bleach solution for an hour and then cleaned thoroughly.
Glassware and other equipment that has been in contact with harmless
microorganisms may simply be washed thoroughly. j. Wearing chemical
splash safety goggles in the laboratory is recommended. •See
Chapter IX.C.4, Microbiology–Decontamination and Disposal of Materials.
Guidance may also be available from a university or research laboratory. 2. Staining DNA a. Methylene blue (or a commercial
derivative) is the recommended staining agent for viewing DNA after gel
electrophoresis in the high school laboratory.
i.
Students should wear latex gloves in handling this stain
because it is moderately toxic and will stain skin.
ii.
In disposing of this stain, follow local regulations. Do not
pour methylene blue down the drain without the approval of local authorities. b. Ethidium bromide, a staining
agent, should only be used by, or under the supervision of, a scientist in a facility
where no student exposure will occur. While it is more sensitive and
quicker to use than methylene blue, it is a mutagenic agent. 3. Conducting Gel
Electrophoresis a. Gel boxes
purchased from a biological supply company are recommended. These boxes are
safe for student use if instructions are followed. If home-built boxes must
be used, they should be carefully constructed for safety. b. Electrophoresis
gels are run at high enough electrical voltages (75-140 volts) to cause
severe jolts. Students must be warned against sticking fingers or
electricity-conducting materials into the electrophoresis buffer solution
while the gel box is in operation. 4. Radiation/Radioisotopes Radiation
experiments and the use of radioisotopes are highly regulated by the state of
New Mexico and the federal government. The teacher must be aware of special
precautions needed to work with nuclear materials, including issues related
to the nature of the radioactive sources, student contact, secure storage,
and disposal. There are also license requirements for persons who possess
nuclear materials. For different isotopes, federal and state regulations set
different limits for possession and use. •See
Chapter XI.F.3, Radioisotopes. The
following website offers more information on this topic: G. Greenhouse Maintenance and Operation For schools that have greenhouses
available for biology and environmental classes, the following guidelines are
intended to aid in their smooth maintenance and operation. These guidelines,
which supplement applicable school regulations, apply to any individual
working in the greenhouse area, student or teacher. 1. Guidelines The
following guidelines are designed to ensure that all greenhouse components
are functioning at an adequate level for optimum plant growth and at a safe
level for student use. a. Check water
lines, heating system, fans, and temperature control. These are usually
routine procedures that can be checked by the school maintenance staff. b. Make sure all
automatic equipment is functional and accurate. c. Clean tools after
use and store them appropriately. d. Instruct students
in the proper use of, and conduct in, the greenhouse area. It is recommended that
students be required to obtain the teacher’s permission to enter the
greenhouse. e. Rules which apply
to the greenhouse must be clearly stated and explained to students. It is
important that students understand that the rules are for the safety of both
the organisms in the greenhouse and the students. f. Students and
teachers should be cautioned to handle fertilizer carefully to avoid inhaling
the dust. g. Wash fruits and
vegetables before studying. Eating fruits or vegetables that have been
cultivated in the greenhouse is not recommended unless special care has been
maintained in the growth of such plants. h. Inspect the
greenhouse periodically to prevent the cultivation of unlawful plants such as
marijuana. i. Make sure to
maintain adequate ventilation. Ventilation is especially important when using
pesticides. •See
Chapter IX.G.2, Greenhouse Maintenance and Operation – Pesticides. j. Use organic
methods of pest control when possible. k. Maintain all
equipment so as not to impede the safe movement into and about the greenhouse.
For example, hose lines should be properly mounted and stored to keep the
floor clear. l. Wash hands
thoroughly after working in the greenhouse. 2. Pesticides a. Selecting
Pesticides
i.
Use the least toxic pesticides. Note signal
words found on pesticide labels: ·
Danger = highly toxic. ·
Warning = moderately toxic. ·
Caution = slightly toxic. ·
No caution or warning = relatively non-toxic.
i.
The safest insecticides contain pyrethrins. b. Using Pesticides
i.
Pesticides are toxic and should be used only according to
instructions on container labels.
ii.
Pesticides can enter the body through the skin, mouth or nose.
Before using pesticides, cover up exposed skin with water-repellent clothes
and boots.
iii.
Wear a wide-brimmed hat and a full-face shield.
iv.
Use unlined, natural rubber gauntlet gloves.
v.
Use exhaust hoods and ventilation systems when spraying.
vi.
Do not touch the mouth or face with hands, forearms or
clothing.
vii.
Do not expose a drink or food container to pesticides.
viii.
Wash hands and face immediately after applying pesticides. |
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