Importance of Dissection
Many educators strongly feel that there is no substitute for the hands-on, learning experience of dissection. Susan Offner, a former Outstanding Biology Teacher Award recipient, wrote that, “The learning that occurs in a dissection is qualitatively different from the learning that occurs in a lecture or paper-and-pencil setting. No model, no video, no diagram and no movie can duplicate the fascination, the sense of discovery, wonder and even awe that students feel when they find real structures in their own specimens”.
The National Association of Biology Teachers states, “The NABT acknowledges that no alternative can substitute for the actual experience of dissection or other use of animals and urges teachers to be aware of the limitations of alternatives.”
Furthermore, “Classroom experiences that involve nonhuman animals range from observation to dissection. NABT supports these experiences so long as they are conducted within the long established guidelines of proper care and use of animals, as developed by the scientific and educational community.”
Other reasons to dissect
Dissection is also important because it:
- Helps students learn about the internal structures of animals.
- Helps students learn how the tissues and organs are interrelated.
- Gives students an appreciation of the complexity of organisms in a hands-on learning environment.
- Provides one of the most memorable and instructive units in a school biology course.
Response to the claim that many animals used in research are stolen pets
Animal activists prey on the emotions of pet owners. They falsely claim that pets are stolen and sold to medical research facilities and suppliers of animals for scientific research. According to the Americans for Medical Progress Educational Foundation, “There is no market for stolen pets in biomedical research. Well over ninety percent of the animals used in medical research are rodents. Dogs and cats account for less than one percent of the total number of lab animals needed by researchers.”
The US Department of Agriculture, under the Animal Welfare Act, governs the procurement of animals. Carolina is proud to have an outstanding USDA inspection and compliance record, and we are committed to treating all animals in a humane manner.
Sources for Carolina's Dissection Specimen
Carolina obtains animals from many sources—some from cultures, some from natural or managed habitats where seasonal collections are made, and many from the food industry.
Many animals and organisms are dead when we purchase them. For example, fishermen supply fish and sharks, and the fishing bait industry supplies earthworms.
Where does Carolina obtain the cats used for dissection?
Animal shelters furnish euthanized cats that would be destined for the landfill were we unable to utilize them for science classrooms.
Where does Carolina obtain the fetal pigs used for dissection?
Abattoirs, producers of sausage, supply fetal pigs that would otherwise be considered offal and sent to the landfill.
Where does Carolina obtain the frogs used for dissection?
The current source for most preserved frogs for biology has an interesting history. Several decades ago, an area of desert was converted to farmland through irrigation. Man’s changing of that land use also resulted in a large increase in the frog population in this area. One industry that emerged from this new resource is the provision of frog legs for food. A fraction of the grass frogs collected from that man-made habitat are preserved for biological study.
What if a student objects to dissection?
The National Association of Biology Teachers “encourages teachers to be approachable and responsive to substantive student objections to dissection and to provide appropriate lessons for those students. At the same time, NABT urges teachers to be aware that alternatives to dissection have their limitations. NABT supports the use of these materials as adjuncts to the educational process but not as exclusive replacements for the use of actual organisms.”
What is the difference between a fixative and a preservative?
Many people use the words “fixative” and “preservative” interchangeably. However, these solutions serve very different purposes when it comes to preserved specimens.
A fixative is initially used to “fix” a specimen’s tissues on a molecular level. These chemicals halt biological processes, preventing decomposition and decay. They also stabilize the structure of tissues.
A preservative, also called a holding solution, is used to store fixed specimens. These solutions prevent bacterial growth, contamination, and desiccation of the specimens.
After fixation, specimens are then transferred to a preservative (holding solution), in which they are stored and then shipped.
What chemicals are used to fix preserved specimens? Are they dangerous?
Carolina’s Perfect Solution®
Carolina’s Perfect Solution® is both a tissue fixative and preservative. Carolina developed it as an alternative to traditional formalin-fixed specimens. This fixative produces specimens with life-like color and texture, while eliminating concerns about formaldehyde exposure, hence eliminating the formaldehyde odor. Although we do not disclose the composition of this solution, independent laboratory testing confirms that it is safe and non-toxic.
Formalin
The most well-known tissue fixative is formalin, an aqueous solution of formaldehyde and a stabilizing chemical, usually methanol.
Formaldehyde is a gas at room temperature. Per the United States Consumer Product Safety Commission (CPSC), exposure to this gas can cause “adverse health effects, such as eye, nose, throat, and skin irritations, coughing, wheezing, and allergic reactions.” The CPSC states that “long-term exposure to high levels of formaldehyde has been associated with cancer in humans.”
Many specimens used in science education are initially fixed with formalin. These include Carolina’s Carosafe® specimens along with most specimens from other science education suppliers.
After reading about the hazards of formaldehyde, using these specimens may seem dangerous. However, initial formaldehyde concentration in fixatives is low, and most science supply companies use various procedures after tissue fixation, such as water baths and chemical scavengers, to minimize the amount of formaldehyde off-gassing.
At Carolina, Carosafe® specimens are initially fixed with formalin and then transferred to Carosafe®, a formaldehyde-free holding solution. This preservative is a propylene glycol solution. Propylene glycol is a common additive in foods and cosmetics. Holding specimens in this solution reduces the presence of formaldehyde, thereby diminishing or eliminating unpleasant odor.
Glutaraldehyde
Glutaraldehyde is another well-known fixative. It can replace formaldehyde and allows for fixation without formaldehyde, which may be dictated by school or state policy. Formaldehyde is a confirmed carcinogen–prolonged and significant exposure increases cancer risk. There has not been such a determination regarding glutaraldehyde. However, from an acute risk perspective, the effects of the two are similar.
While OSHA has not established a permissible exposure level for glutaraldehyde, the American Conference of Government Industrial Hygienists (ACGIH) has established a recommended threshold limit value (TLV) of 0.05 ppm for glutaraldehyde, as compared to a TLV of 0.3 ppm for formaldehyde. Glutaraldehyde is acutely toxic and is not without risk.
*Please note that Carolina does not fix any specimens with glutaraldehyde.
What is off-gassing? Should I be concerned about it?
Off-gassing is the release of airborne chemicals that were previously trapped in an object. These airborne chemicals are called volatile organic compounds, or VOCs.
Thousands of common products such as paints, air fresheners, cleansers, glues, and furniture release VOCs. The effects of exposure vary depending on the type of chemical, chemical concentration, and exposure time. Some VOCs have no known health effects, while others can cause minor symptoms, such as eye irritation, or even major health problems, like cancer.
To address recent off-gassing and VOC concerns, we sent preserved fetal pig specimens to an independent lab for VOC analysis. Carolina’s Perfect Solution® specimens, Carosafe® specimens, and a leading competitor’s specimens were tested in simulated dissections without ventilation.
For Carolina specimens, only two VOCs were found in measurable amounts—formaldehyde and ethanol. However, the concentrations of these chemicals were impressively low, and significantly below regulatory or recommended exposure limits.
The OSHA permissible exposure limit for formaldehyde is 0.75 ppm (measured as an 8-hour time-weighted average). Irritation of the respiratory tract can occur at 0.1 ppm. Both Perfect Solution and Carosafe® specimens had average airborne formaldehyde concentrations below 0.04 ppm with no ventilation. This level is not high enough to be detected by most handheld VOC meters.
For ethanol, the OSHA permissible exposure limit is 1000 ppm. Both types of Carolina specimens had average airborne ethanol concentrations below 5 ppm with no ventilation.
Why do Carolina's preserved specimens have a warning about cancer on the labels?
This warning was added to preserved specimen labels because of a California law referred to as Proposition 65. In California, any chemical known to cause cancer or birth defects is put on a published list that is updated annually. There are over 800 chemicals on the list. If a product contains any of them, at any concentration, the item must be labelled with a “clear and reasonable” warning label.
Formaldehyde is on California’s Proposition 65 list of carcinogens. As shown above, the formaldehyde concentrations in Carolina’s preserved specimens is significantly lower than any level of concern. However, because it is present, we must appropriately label each specimen with this warning.
Labeling only specimens being shipped to California is time and labor intensive, so we include this warning on all preserved specimens.
What type of personal protective equipment (PPE) will I need to perform a dissection?
Anyone performing a dissection or handling preserved specimens should wear the following PPE: gloves, safety glasses or goggles, and an apron.
If any fluids or preserved tissues come in contact with bare skin, what should I do?
Immediately wash the area with water. The necessity of any further treatment would not be expected. Of course, as always, should an unexpected symptom occur, seek medical attention.
Is special ventilation needed for a dissection activity?
Local ventilation (e.g., fume hoods) is not required when using any of Carolina’s preserved specimens. However, some ventilation is recommended in all cases.
When using Carosafe® specimens, good ventilation is suggested to minimize formaldehyde exposure. Though off-gassing from these specimens is minimal, teacher and student safety and comfort are paramount, and compliance with OSHA regulations is crucial.
With Carolina’s Perfect Solution® specimens, formaldehyde exposure is not a concern. With both Perfect Solution and Carosafe® specimens, however, air flow in the lab increases most students’ comfort level as it minimizes the biological and chemical smells that may be present.
Do specimens require special disposal?
Carolina’s Perfect Solution® and Carosafe® specimens are not classified as federal hazardous waste nor are they biohazards. Therefore, in most cases, they can be disposed of as regular waste destined for a landfill or incinerator. Specimens should be double-bagged and sealed before being placed in the trash.
Extra holding fluids are not considered hazardous wastes and can usually be discarded down the drain into the sanitary sewer system. However, if your school or home has a septic tank system, ask an administrator or expert before you dispose of the fluids as they could upset the microbial balance that is vital to a septic system.
Although Carolina specimens and their holding fluids are not hazardous wastes or biohazards under federal and almost all state regulations, you should always check with your local solid waste or wastewater authority before disposing of them. This may mean contacting the local government office that oversees waste disposal, the local landfill, your waste disposal company, or the local wastewater treatment plant. Check with your school or university safety officer for any disposal guidelines.
Where can I find the safety data sheets (SDS) for Carolina's preserved specimens?
Use these links to access the sheets:
Other places to find the sheets:
- Resources tab on each preserved specimen product page
- QR code on each specimen label
What should I do if I have additional safety questions or concern?
If you have additional questions about disposal or other safety concerns, please contact our Product Safety and Compliance Manager, Keith Barker, at keith.barker@carolina.com
Many people use the words “fixative” and “preservative” interchangeably. However, these solutions serve very different purposes when it comes to preserved specimens.
A fixative is initially used to “fix” a specimen’s tissues on a molecular level. These chemicals halt biological processes, preventing decomposition and decay. They also stabilize the structure of tissues.
A preservative, also called a holding solution, is used to store fixed specimens. These solutions prevent bacterial growth, contamination, and desiccation of the specimens.
After fixation, specimens are then transferred to a preservative (holding solution), in which they are stored and then shipped.
Carolina’s Perfect Solution®
Carolina’s Perfect Solution® is both a tissue fixative and preservative. Carolina developed it as an alternative to traditional formalin-fixed specimens. This fixative produces specimens with life-like color and texture, while eliminating concerns about formaldehyde exposure, hence eliminating the formaldehyde odor. Although we do not disclose the composition of this solution, independent laboratory testing confirms that it is safe and non-toxic.
Formalin
The most well-known tissue fixative is formalin, an aqueous solution of formaldehyde and a stabilizing chemical, usually methanol.
Formaldehyde is a gas at room temperature. Per the United States Consumer Product Safety Commission (CPSC), exposure to this gas can cause “adverse health effects, such as eye, nose, throat, and skin irritations, coughing, wheezing, and allergic reactions.” The CPSC states that “long-term exposure to high levels of formaldehyde has been associated with cancer in humans.”
Many specimens used in science education are initially fixed with formalin. These include Carolina’s Carosafe® specimens along with most specimens from other science education suppliers.
After reading about the hazards of formaldehyde, using these specimens may seem dangerous. However, initial formaldehyde concentration in fixatives is low, and most science supply companies use various procedures after tissue fixation, such as water baths and chemical scavengers, to minimize the amount of formaldehyde off-gassing.
At Carolina, Carosafe® specimens are initially fixed with formalin and then transferred to Carosafe®, a formaldehyde-free holding solution. This preservative is a propylene glycol solution. Propylene glycol is a common additive in foods and cosmetics. Holding specimens in this solution reduces the presence of formaldehyde, thereby diminishing or eliminating unpleasant odor.
Glutaraldehyde
Glutaraldehyde is another well-known fixative. It can replace formaldehyde and allows for fixation without formaldehyde, which may be dictated by school or state policy. Formaldehyde is a confirmed carcinogen–prolonged and significant exposure increases cancer risk. There has not been such a determination regarding glutaraldehyde. However, from an acute risk perspective, the effects of the two are similar.
While OSHA has not established a permissible exposure level for glutaraldehyde, the American Conference of Government Industrial Hygienists (ACGIH) has established a recommended threshold limit value (TLV) of 0.05 ppm for glutaraldehyde, as compared to a TLV of 0.3 ppm for formaldehyde. Glutaraldehyde is acutely toxic and is not without risk.
*Please note that Carolina does not fix any specimens with glutaraldehyde.
Off-gassing is the release of airborne chemicals that were previously trapped in an object. These airborne chemicals are called volatile organic compounds, or VOCs.
Thousands of common products such as paints, air fresheners, cleansers, glues, and furniture release VOCs. The effects of exposure vary depending on the type of chemical, chemical concentration, and exposure time. Some VOCs have no known health effects, while others can cause minor symptoms, such as eye irritation, or even major health problems, like cancer.
To address recent off-gassing and VOC concerns, we sent preserved fetal pig specimens to an independent lab for VOC analysis. Carolina’s Perfect Solution® specimens, Carosafe® specimens, and a leading competitor’s specimens were tested in simulated dissections without ventilation.
For Carolina specimens, only two VOCs were found in measurable amounts—formaldehyde and ethanol. However, the concentrations of these chemicals were impressively low, and significantly below regulatory or recommended exposure limits.
The OSHA permissible exposure limit for formaldehyde is 0.75 ppm (measured as an 8-hour time-weighted average). Irritation of the respiratory tract can occur at 0.1 ppm. Both Perfect Solution and Carosafe® specimens had average airborne formaldehyde concentrations below 0.04 ppm with no ventilation. This level is not high enough to be detected by most handheld VOC meters.
For ethanol, the OSHA permissible exposure limit is 1000 ppm. Both types of Carolina specimens had average airborne ethanol concentrations below 5 ppm with no ventilation.
This warning was added to preserved specimen labels because of a California law referred to as Proposition 65. In California, any chemical known to cause cancer or birth defects is put on a published list that is updated annually. There are over 800 chemicals on the list. If a product contains any of them, at any concentration, the item must be labelled with a “clear and reasonable” warning label.
Formaldehyde is on California’s Proposition 65 list of carcinogens. As shown above, the formaldehyde concentrations in Carolina’s preserved specimens is significantly lower than any level of concern. However, because it is present, we must appropriately label each specimen with this warning.
Labeling only specimens being shipped to California is time and labor intensive, so we include this warning on all preserved specimens.
Anyone performing a dissection or handling preserved specimens should wear the following PPE: gloves, safety glasses or goggles, and an apron.
Immediately wash the area with water. The necessity of any further treatment would not be expected. Of course, as always, should an unexpected symptom occur, seek medical attention.
Local ventilation (e.g., fume hoods) is not required when using any of Carolina’s preserved specimens. However, some ventilation is recommended in all cases.
When using Carosafe® specimens, good ventilation is suggested to minimize formaldehyde exposure. Though off-gassing from these specimens is minimal, teacher and student safety and comfort are paramount, and compliance with OSHA regulations is crucial.
With Carolina’s Perfect Solution® specimens, formaldehyde exposure is not a concern. With both Perfect Solution and Carosafe® specimens, however, air flow in the lab increases most students’ comfort level as it minimizes the biological and chemical smells that may be present.
Carolina’s Perfect Solution® and Carosafe® specimens are not classified as federal hazardous waste nor are they biohazards. Therefore, in most cases, they can be disposed of as regular waste destined for a landfill or incinerator. Specimens should be double-bagged and sealed before being placed in the trash.
Extra holding fluids are not considered hazardous wastes and can usually be discarded down the drain into the sanitary sewer system. However, if your school or home has a septic tank system, ask an administrator or expert before you dispose of the fluids as they could upset the microbial balance that is vital to a septic system.
Although Carolina specimens and their holding fluids are not hazardous wastes or biohazards under federal and almost all state regulations, you should always check with your local solid waste or wastewater authority before disposing of them. This may mean contacting the local government office that oversees waste disposal, the local landfill, your waste disposal company, or the local wastewater treatment plant. Check with your school or university safety officer for any disposal guidelines.
Use these links to access the sheets:
Other places to find the sheets:
- Resources tab on each preserved specimen product page
- QR code on each specimen label
If you have additional questions about disposal or other safety concerns, please contact our Product Safety and Compliance Manager, Keith Barker, at keith.barker@carolina.com
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