Carcinogenic substances banned from chemistry
Doing experiments with carcinogenic substances is no longer allowed in chemistry. Not everyone is happy with that. "Our profession is being eroded."
Picture: Type tank
Beautiful purple-red colors give the acid-base indicator phenolphthalein when the acidity is above 10. “Many teachers use that material in their experiments,” says Jan van Lune, chemistry teacher and head of the office of the Netherlands Association for Education in Natural Sciences (NVON). In principle, schools should look for an alternative to this commonly used substance. The substance is on the list of carcinogenic, mutagenic and toxic for reproduction substances of the Ministry of Social Affairs. Abbreviated as CMR substances.
The labor market and training fund Voion for secondary education, which includes employers and unions, recently published a memorandum containing clear advice. The platform advises against the use of carcinogenic substances that the Social Affairs and Employment has on its list. Those substances must be replaced by non-carcinogenic substances. If schools do want to use a substance on the list, they must take precautions and assess the risks.
Strict requirements
“Many schools have no knowledge of all the strict requirements,” says Voion employee Rick van Workum. He notices that things are being trivialized. “Then we hear, for example: We use very little of that stuff. Or: This is also in everyone's sink cupboard. The rules seem overly strict, but the point is that it is about who is responsible. It is a misunderstanding that what is allowed at home is also allowed at school.
The rules seem overly strict, but it's about who's responsible
The Working Conditions Act applies at schools. Employees must not run any risk in their work. “The tricky part is that you often do not know how much of a substance you inhale, how much is atomized, how much it has been diluted and what the health risks are. Schools often do not have the right measuring equipment for that, ”says Van Workum. It is important to look for alternative substances for testing.
Twenty years ago, chemistry teacher Jan Hop did large demonstration experiments with ammonium dichromate that was heated. That gave spectacular volcano effects. (Image: Type tank)
If teachers do want to use a substance on the list, they must comply with strict rules. Van Workum explains: “They first have to see which substances they use in tests and which ones are on that list. Then they have to check the substance properties for how dangerous or carcinogenic they are and what the limit values are. Then they have to find out in which situations they use the material and who has to deal with it how often. So you actually make a complete analysis of all risks. Technical teaching assistants and teachers often wonder what the chance is that you will actually develop cancer from a substance. That question is not easy to answer. The limit values are based on a risk of one extra case of cancer out of ten thousand people. ”
Holding back
Chemistry teacher Jan Hop remembers experiments that were spectacular, but are no longer possible. He teaches supportive lessons at a secondary school in Drenthe and is about to retire. “Twenty years ago I did large demonstration tests with ammonium dichromate that we heated. That gave spectacular volcano effects, ”he says. “Now we can only show that with YouTube videos. Sometimes that's a shame. ”
Jan van Lune of the NVON trade association is happy that there is a list and that substances must be replaced. The trade union was also in talks about the note. “Working safely is important, but it must be realistic. The dangers are in some cases so low, for example with alcohol which is also on the list (see box). We do get back from our teachers that they think their subject is being eroded now that many tests can no longer be done. ”
Van Lune thinks it has to do with habituation. "It feels strange when you do something for years that is suddenly no longer allowed." The trade association is working on an inventory of substances that teachers consider indispensable. They approached chemistry sections for this. NVON then wants to describe specific tests to see whether exceptions are possible. “For example, that you turn a test into a demonstration with extraction. We have to wait and see what comes out. I myself had to get used to it first, but now I think: How can I teach students the same with other materials. ”
"Working safely is important, but it must be realistic," says Jan van Lune of NVON. In some cases, the dangers are so low. can be done.” (Image: Type Tank)
Many fabrics have already been replaced at the Lorentz Casimir Lyceum in Eindhoven. Technical teaching assistant Cees Meeuwisse sees no problems, although the subject teachers are more reluctant to replace them. “I don't see any reason to work with carcinogens,” he says. “With home-garden-and-kitchen products you can just as well do cool experiments and let students discover chemical principles”.
Lemons
With lemons from Lidl, for example. Meeuwisse: “Titration is great fun, especially if students are allowed to squeeze their own lemon and use it instead of a chemical from the pantry. For example, you want to know the concentration of citric acid in lemon juice. Dilute lemon juice is then titrated with sodium hydroxide solution and the end of the reaction is determined by the color change of an indicator. Previously this was phenolphthalein, this substance is on the list. Now we use bromothymol blue. Still a chemical, but not on the CMR list and safer to use. The subject of chemistry is really not getting any less. "
With home-garden-and-kitchen resources you might as well do cool experiments
It is often the technical teaching assistants who prepare tests, create solutions and clean up the laboratory waste. Meeuwisse has noticed more awareness among colleagues he speaks to. “However, it is often difficult to adjust or change something. In that regard, education is an oil tanker that now has to go 3 degrees to starboard. That is not going quickly. ”
Alcohol also on the list
Under the heading of ethanol, alcohol is also on the list of carcinogenic substances. There is a lot of discussion about this among chemistry teachers. Jan van Lune of the NVON trade association says that only very small quantities are used. “I don't see a replacement anytime soon either. So it sometimes feels crooked that you have to make an entire analysis for that or have to replace it, while students already get more in when they go out.” Rick van Workum, employee at the labor market platform Voion, acknowledges that this material is always cited when there is discussion. “They think that's ridiculous,” says Van Workum. “Due to laws and regulations, we recommend replacing this substance as well. The only reason to use it is if it is technically impossible to replace the fabric and there is a real need. Ultimately, the question is what is more important: the lesson education or the risk of health damage. We don't know that outcome. Voion therefore advises against it."
The note from Voion with the advice about the substances and additional explanation about the Working Conditions Act can be found here voion.nl This article appeared in the Education Magazine of July 2018. Would you also like to receive the magazine every month? Then become member of the AOb.
