EDTA, soap, you, and the environment.

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This morning I was reading a thread here and someone (who shall remain nameless for all their shadowy vagueness) mentioned their non-use of EDTA and its toxicity. Now I ‘grew up’ with EDTA in biomedical uses and am always a little sceptical when toxicity and environmental issues get thrown about on internet fora. All the same it’s been my observation that the nameless person does not tend to exaggerate or talk gibberish. So I decided to take a quick (not really) look at EDTA. Here’s the executive summary … my interpretation of what I found along with a few excerpts and references.

Please note, this is *my* analysis and is the result of my attempt to sort fact from fiction and to put the risks into a perspective I am comfortable with. Others will form and will hold different views.
Please forgive me my gratuitous reference to bacon. It's actually there to bring some focus onto the fact that a wide range of factors contribute to our personal individual risk management decisions.

“EDTA”, ethylenediaminetetraacetic acid or edetic acid is used in soaps and other bodycare products mainly because of its ability to bind, or chelate, metal ions. This action can both reduce the hardness of water and act as a preservative. This use should not be surprising given that edetic acid was discovered, early last century, as a lipid preservative in the metabolism of seasonal plants.

Edetic acid is widely used in many many industries, including medicine and dentistry, water treatment, a wide variety of manufacturing, and soil decontamination. Over 80 million metric tons of edetic acid are produced per year, and so it is a relatively inexpensive soap-making additive.

Edetic acid is not entirely benign, as may be suggested by its plant origins and medical use. It has a relatively low direct toxicity to humans but has been found to be both cytotoxic and weakly genotoxic in laboratory animals. It is not well absorbed via the skin and applied, or inhaled aerosolized, cosmetic products do not produce levels at which toxic effects have been observed. Edetic acid is, however, very stable and poorly biodegradable. It’s break-down pathways can include dioxopiperazine, which is a persistent organic pollutant (see 2001 Stockholm Convention).

“EDDS”, Ethylenediamine-N,N'-disuccinic acid, is closely related to edetic acid and has many similar properties. EDDS is much more biodegradable that edetic acid and has seen increasing industrial use over the last two decades.

My favourite quote: “The recalcitrance of EDTA in natural environments is of considerable concern since the effective metal-binding properties are suspected to have undesirable environmental consequences such as the remobilization of heavy metals from river sediments.” [1]

My stance, having now taken a look at the topic: Bacon is more directly dangerous to people. EDTA does have significant and avoidable adverse environmental impact. All the same I’m not going to buy any more EDTA. I will slowly use up what little I hold and keep an eye out for less harmful alternatives.

____

1. p194 Biodegradation and Persistence: Volume 2 of The Handbook of Environmental Chemistry Reactions and Processes. B Beek - Ed, Springer, 2006. ISBN 3540680969.

Here’s a few of the things I read, along with some comments /thoughts about them …

2. PUBCHEM, always a good starting point.

https://pubchem.ncbi.nlm.nih.gov/compound/edta#section=Top

3. 1963, but still …

Toxic side effects of ethylenediaminetetraacetic acid
Harry Foreman
Journal of Chronic Diseases. Volume 16, Issue 4, April 1963, Pages 319-323​

4. This Lanigan paper is little dated, but one of the background reports on the safety of EDTA. I can only access the abstract, which is available via PUBMED, although full text may be available with a little more searching.

Final Report on the Safety Assessment of EDTA, Calcium Disodium EDTA, Diammonium EDTA, Dipotassium EDTA, Disodium EDTA, TEA-EDTA, Tetrasodium EDTA, Tripotassium EDTA, Trisodium EDTA, HEDTA, and Trisodium HEDTA.
Lanigan RS, Yamarik TA.
Int J Toxicol. 2002;21 Suppl 2:95-142.

EDTA (ethylenediamine tetraacetic acid) and its salts are substituted diamines. HEDTA (hydroxyethyl ethylenediamine triacetic acid) and its trisodium salt are substituted amines. These ingredients function as chelating agents in cosmetic formulations. The typical concentration of use of EDTA is less than 2%, with the other salts in current use at even lower concentrations. The lowest dose reported to cause a toxic effect in animals was 750 mg/kg/day. These chelating agents are cytotoxic and weakly genotoxic, but not carcinogenic. Oral exposures to EDTA produced adverse reproductive and developmental effects in animals. Clinical tests reported no absorption of an EDTA salt through the skin. These ingredients are likely, however, to affect the passage of other chemicals into the skin because they will chelate calcium. Exposure to EDTA in most cosmetic formulations, therefore, would produce systemic exposure levels well below those seen to be toxic in oral dosing studies. Exposure to EDTA in cosmetic formulations that may be inhaled, however, was a concern. An exposure assessment done using conservative assumptions predicted that the maximum EDTA dose via inhalation of an aerosolized cosmetic formulation is below that shown to produce reproductive or developmental toxicity. Because of the potential to increase the penetration of other chemicals, formulators should continue to be aware of this when combining these ingredients with ingredients that previously have been determined to be safe, primarily because they were not significantly absorbed. Based on the available data, the Cosmetic Ingredient Review Expert Panel found that these ingredients are safe as used in cosmetic formulations.

https://www.ncbi.nlm.nih.gov/pubmed/12396676
I can’t find a fulltext version.​

5. This Oveido paper is actually quite an informative read on the environmental aspects of EDTA. Good background info.

EDTA: THE CHELATING AGENT UNDER ENVIRONMENTAL SCRUTINY
Claudia Oviedo and Jaime Rodríguez
Quim. Nova, Vol. 26, No. 6, 901-905, 2003

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422003000600020
Fulltext: https://www.researchgate.net/publication/26352747_EDTA_The_chelating_agent_under_environmental_scrutiny

6. This Pinto publication discusses more viable, and biodegradable, alternatives.

Biodegradable chelating agents for industrial, domestic, and agricultural applications—a review
Pinto, I.S.S., Neto, I.F.F. & Soares, H.M.V.M.
Environ Sci Pollut Res (2014) 21: 11893. https://doi.org/10.1007/s11356-014-2592-6

https://www.ncbi.nlm.nih.gov/pubmed/24554295
Fulltext: https://www.researchgate.net/public...mestic_and_agricultural_applications-a_review

7. If anyone can find a fulltext or PDF version of this book I’d appreciate it. It’s no longer listed by the publisher – not sure what to make of that. I cannot find much mention of the editor or the book itself … so am not inclined to spend the money, much as I’d like to read it.

EDTA: Synthesis, Uses & Environmental Concerns
Hardback, ISBN101628081465
Andris Molnar (Ed)
2013 Nova Science Publishers Inc​
 

paradisi

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Not sure why you don't feel you can directly confront the person you are arguing with, but-- as you note-- EDTA is a persistent groundwater pollutant.

"Edetic acid is, however, very stable and poorly biodegradable. It’s break-down pathways can include dioxopiperazine, which is a persistent organic pollutant (see 2001 Stockholm Convention)."

And that's enough reason for many to not use it.

Re your comparison to bacon.. safety of ingestion is a wholly different thing from safety when released into the environment. It might not hurt a person to wash with, or ingest, EDTA, but it's still a groundwater pollutant.
 
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Not sure why you don't feel you can directly confront the person you are arguing with, but-- as you note-- EDTA is a persistent groundwater pollutant.

"Edetic acid is, however, very stable and poorly biodegradable. It’s break-down pathways can include dioxopiperazine, which is a persistent organic pollutant (see 2001 Stockholm Convention)."

And that's enough reason for many to not use it.

Re your comparison to bacon.. safety of ingestion is a wholly different thing from safety when released into the environment. It might not hurt a person to wash with, or ingest, EDTA, but it's still a groundwater pollutant.
I'm not sure the FP has an intention of confronting, merely to open up discussion. I think it was probably written that way in good humour, not confrontational intent.
 

szaza

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Great read @dxw ! Thanks for doing the research and summarizing what you found here. It helped me make up my mind and I'm sure others will find it useful as well!
 

Jenn Lee

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Yes, also a great summary! Thanks for the information. I haven't been using it in my soaps, but had recently purchased a small amount to experiment with not knowing anything about the environmental effects because it's so ubiquitous. Sometimes the things we use most really are not great and it's a shock to find out the deeper truths. Huh.
 
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