Comparing (eco)toxicity of commercial and home-made laundry detergents
I have worked as a research chemist for many years in a water treatment company. The knowledge I acquired during that period of my life allows me to be appalled when I read the chemical composition of some commercial or industrial products. The thing is, alternatives do exist. The reason why these are not implanted on an industrial scale, I’ll let you guess…
What I will do here is follow up on an inspiring article I read a few days ago, written by Delphine Stein.
Delphine presents an alternative recipe to laundry detergents. She developed it herself by trial and error, and has been using it now for years with success.
In her article though, she admits lacking certain knowledge in water chemistry, which implies that she couldn’t propose strong scientific arguments on why it should be used instead of what is proposed in supermarkets.
This is where I jump in.
This article will compare the toxicity and eco-toxicity of Delphine’s eco-aware laundry powder recipe with that of a commercial laundry powder you can buy in supermarkets.
Delphine’s homemade formula
Let’s start with Delphine’s home-made recipe and discuss the ingredients.
Marseille soap is made by saponification. Saponification is a well-known reaction that has been used for millennia in order to produce soap:
Fatty esters (triglycerides) + caustic soda –> glycerol + sodium salt of fatty acids.
Fatty acids easily biodegrade in the environment and are non toxic for animals and humans [Source].
Sodium carbonate (Na2CO3) should be handled with care by humans. It can provoke strong irritations upon contact and inhalation. Consequently, use gloves, eye protection and a mask when manipulating large quantities [Source]. Sodium carbonate is not toxic or ecotoxic per se, it is its buffering pH that can cause a problem if released in the environment without care. It should be neutralized first which is done easily in water treatment plants.
Sodium bicarbonate (NaHCO3) is non-toxic and non-ecotoxic. As with sodium carbonate, bicarbonate has a strong pH buffering power (that’s part of why it’s effective), it should not be released in the environment without prior neutralization.
Percarbonate is actually sodium carbonate bounded with peroxide. Peroxide is an oxidant so it is harmful to life, however, when released, it degrades into sodium carbonate, and peroxide which turns into oxygen and water. [Source]. During such degradation, molecules surrounding the peroxide can be oxidized, but this process can occur in the sewer and at a water treatment plant. So when handled correctly, it is eco-friendly. In the home-made formulation, Percarbonate takes the role of the bleaching agent.
Essential oils are used to perfume the laundry powder. They do not intervene in the cleaning process, although they can act against bacteria and fungi, protecting clothes. That’s a good thing, right? Well, this is actually also the problem… many essential oils are eco-toxic, but the concentration being very low it may be acceptable to use them in certain conditions.
By definition, essential oils contain aromatic compounds and should be treated with care. Some can be very toxic, even carcinogenic: You shouldn’t dump any essential oil in your laundry just because it smells good. Check the toxicity and ecotoxicity of the oil or oils you wish to use first.
The step by step procedure to formulate your own laundry powder is provided on Delphine’s post.
A typical commercial formula
Now let’s discuss the ingredients of a typical laundry powder found in supermarkets:
Oxygen based bleaching agents… Well the problem here, is that we do not really know what these are… if they are percarbonate-based, it is not better or worse than the home made product. On the other hand percarbonates have limited action below 60C, so industrials tend to try and boost effectiveness by adding chlorine based products (bleach derivatives), and the aqua toxicity of the degradation products which are chlorinated is just a nightmare.
Perborate is sometimes used also, although not as bad as chlorinated products, it is less eco-friendly than percarbonate. In addition it requires an activator, tetraacetylethylenediamine. The name might scare you but this latter compound is actually OK [source].
For anionic surfactants, well, it is difficult to say here too: the molecular structure is not given. In the best case scenario these are standard fatty acids used in home-made soaps.
Non ionic surfactant: In hard waters (containing Calcium for example), standard surfactants can be deactivated. This is why non-ionic surfactants are added. These often take the form of alcohol ethoxylate, which can be highly toxic to aquatic organisms. Again, the fact that the exact formulas are not divulged in their entirety is a scandal, limit criminal.
Phosphonate: Extremely eco-toxic. Phosphonates will degrade readily into ortho-phosphate which is food for green algae. Phosphate released in the environment ends up giving a huge competitive advantage to green algae versus other species. The algae soon covers water surfaces and by doing so, cuts the light from the sun to all life located underneath the surface. This phenomena is called eutrophication and can destroy thriving aquatic ecosystems.
Source picture: http://www.geograph.org.uk/photo/2805400
Zeolites are not chemically toxic: it is the size of the zeolite particles that can cause health issues not their chemical composition. So naturally, when added to water they lose their toxicity. Their roles in laundry powders is to soften the water (remove calcium and magnesium ions that deactivate the ionic surfactants).
Enzymes: These have a beneficial effect in breaking molecules making the stains on clothes. Again the problem here is the non-divulgation of the exact formula. Some enzymes degrade well at relatively low temperatures and are harmless for the environment, some have high risk of spreading out and create large problems for the environment and are toxic…
Which one is used in a specific powder? Not always easy to find out for the basic consumer… Do we trust chemical corporation enough to have carried out an objective and fully funded toxicological and eco-toxicological study? I don’t. I have to remind myself that the primary focus here for these companies is to make profit only…
Optical brighteners: These toxic and eco-toxic compounds are used to make your clothes appear brighter (not cleaner, brighter…). Everything is said in this resource. And again, there is no mention of the detailed molecule used. In any case, use of this additive is just plain bad.
Perfumes: Same here, no info on which molecule is used. Some are perfectly fine, some can be really toxic… We just have to trust the food agencies and the companies. No f****g way!
Coumarin is a mildly toxic vanilla flagrance. It has been banned in some countries as food additive [source].
Geraniol is a flagrance with recognized toxicity. Download link of MSDS(material safety data sheet):
Hexyl Cinnamal is not really toxic for human but very toxic for aquatic life. Download link of MSDS
Polycarboxilate are dispersing polymers that counter water hardness and can synergistically improve the effectiveness of phosphonates as corrosion inhibitor. So in other words, polycarboxilates improve the action of ionic surfactants by dispersing calcium and magnesium in the water, and can help in preventing corrosion. (source: my own research – published internally).
For standard compounds like polyacrylates, toxicity and ecotoxicity is negligible, but again, only the compound’s family name is provided. So in the end, behind a sweet smile one could find a substituted polycarboxilate with active functions that could render it seriously ecotoxic.
Now Let’s Compare!
So, after reading this text or/and consulting the references provided, what do you think?
In my opinion, we are allowed to breathe even if our bodies release green house gases like CO2. A homemade laundry powder is far from ideal, but we as a species, have the right to wash our clothes, in order to keep a good hygiene and minimizing the risk of disease. But to keep that right, we have to make wiser choices in terms of environmental sustainability. Delphine’s formula shows us that alternative solutions to eco-toxic industrial products do exist.
What we can also pick up from this study is that standard laundry powders found in all supermarkets are eco-toxic, aqua-toxic and sometimes even harmful to humans. Worse of all, the lack of clarity about the individual components is very worrying. Are industrials hiding behind the low toxicity averages of a whole family of compounds?
If you do not feel like preparing your own laundry yourself, there are alternatives that you can purchase on the Internet. Armed with what you learned here, you should be able to make the right choices.
As a starting point, check http://grist.org/article/its-a-wash/
Now, it’s up to you… make the right choices for our future!
Background of initial picture : Dr. Jennifer L. Graham | U.S. Geological Survey