Potentially Carcinogenic Dishwashing Detergent Leaching Directly Into the Water Supply.

Fuori O Dentro (2007) Roberto Bernardi Italian (1974- ), Oil on Canvas, Private Collection.

This is a contribution from NNadir.

The article from the primary scientific literature I will discuss today, which is really on dishwashing detergent ingredients, comes from the scientific journal Environmental Science and Technology's ASAP section, and is featured on the website of the American Chemical Society, the world's largest scientific organization.

Here is a link to the paper: From Dishwasher to Tap? Xenobiotic Substances Benzotriazole and Tolyltriazole in the Environment

I happen to be familiar with the chemistry of cleaning agents and have been involved - albeit long ago in my career - in some fairly high level discussions of their formulations. Because of my ongoing interest in the ecological chemistry of water, born of my youth on Long Island, - geologically a sandy morraine, now having has widely distributed septic systems - and because I happen to have a septic system and a well on my current property in New Jersey, I have continued to keep up on the environmental literature of water and household chemicals.

Some of the more current issues - issues for instance involving residual pharmaceutical agents and their metabolites - have probably been issues for many years, and have only become understood as a result of improved detection, primarily LC/MS/MS. However - and this was certainly true when I was a child on Long Island - the formulations of cleaning agents have been a known environmental problem for decades.

The compounds in question here are known as benzotriazoles.

Triazoles are compounds having a 5 membered ring system with three nitrogens contained in the ring. Triazoles are widely used in the synthesis of many important drugs, where from a structural standpoint, they function as a mimetic to carboxylic acid functions (tetrazoles, having four nitrogens are also used in this way) where the carboxylic function might induce problematic metabolism of drug compounds.

Many important drugs contain triazoles, including several that are important agents in the treatment of breast cancer. However many of these triazoles are 1,3,4 isomers.

1,2,3 triazoles are found in a few drugs, and used in the direct synthesis of many others. People who have worked in peptide chemistry or related chemistries will be familiar with the famous compound HOBt, which is a hydroxbenzotriazole.

Apparently, and I wasn't aware of this until just now, a compound closely related to HOBt is used widely in dish detergent.

In recent years, regulatory agencies around the world have just begun to require the understanding of the toxicology of HPV's "high production volume" chemicals. Many of these, gasoline and crude oil come to mind are well known carcinogens and mutagenic agents, but basically, because they are (niavely I think) considered essential to the world economy, they are basically ignored, with the exception of the exceedingly stupid announcement on gas pumps everywhere in California that read "This material contains chemicals known by the State of California to cause cancer."

Um, well, duh...

Besides what is known about gasoline, there are many high production volume chemicals that have had far less little examination of their toxicology. This has begun, only recently, to change. In Europe for instance, this has begun to change, and there is for instance, the REACH initiative, where "REACH" is an acronym for Registration, Evaluation, Authorisation and Restriction of Chemical substances.

The, um, "Restriction" part doesn't involve things that are known to be highly toxic, like, um, say gasoline, of course, since a German ban on gasoline would cause the German economy to collapse in a New York second like a substandard coal mine in Ukraine.

Well then...

About the referenced and linked paper, what follows is some excerpts:

The contamination of natural waters by chemicals is a major concern in many parts of the world, and as new chemicals are introduced or others find new applications, and analytical methods improve, the occurrence of previously undetected chemicals, termed “emerging contaminants”, in wastewaters and receiving waters is frequently reported.1,2 Much attention has focused on compounds known to exhibit biological activity at low concentrations, in particular pharmaceuticals, steroid estrogens, and other endocrine disruptors. The occurrence of these compounds began to receive attention during the 1990s when they were linked to toxicological effects in fish.3 However, consumer products such as washing powders containing detergents, bleaching agents, and other ingredients are used in higher volumes than pharmaceuticals and may also contribute to the wide dispersive occurrence of xenobiotocs in wastewaters.4 One class of chemical corrosion inhibitors that has been incorporated into dishwashing detergents to reduce the corrosion of nonferrous metals5 is 1H-benzotriazole (BT) and 4- or 5-methyl-1H-benzotriazole, used as a technical mixture and commonly called tolyltriazole (TT). In addition to use in consumer products, they find more extensive use in industrial products, such as brake fluids, motor vehicle antifreeze, and aircraft deicing fluids.6

Wow, brake fluids and motor vehicle antifreeze could be bad for you? Who knew?

The introduction continues with some scientific units describing the detection of these compounds in German and Swiss rivers.

The first report on their occurrence in the aquatic environment was in the Glatt River, Switzerland, where they occurred in all sewage treatment work (STW) effluents surveyed and were detected at concentrations up to 3690 ng/L (BT) and 628 ng/L (TT) in the river.7 Subsequently, their presence has been reported in a further six Swiss rivers,8 as well as in rivers in Germany, with concentrations of BT ranging from 130 to 3500 ng/L in the Rhine9 and from 38 to 1474 ng/L in theMain, Hengstbach, and Hegnach collectively.10 Concentrations of BT and TT were among the highest of 36 polar pollutants detected in a survey of European rivers.11

Wow. They've been detected.

The authors, who are British, have in the current work, investigated rivers in the UK where, unsurprisingly the same compounds are widely detected.

For anyone reading this diary who may be an analytical chemist (all others should skip this paragraph) the triazoles in drinking water, rivers, and sewage outfall pipes on rivers by (as I suggested) by LC/MS/MS following extraction via SPE, and using a triple quad mass spec. The method is fully described in Environ. Sci. Pollut. Res. 2006, 13, 333–341. The triple quad was an API-4000, and the LLOQ for BT was 8 ng/ml and for TT 3 ng/ml, not a particularly low LLOQ for a triple quad, although not much sensitivity was required, since most samples vastly exceeded this concentration.

The topic paper of this diary determined the concentrations of BT and TT to be many thousands of times the LLOQ. For the former, one sample was found to contain 3605 ng/L of the former, and 5700 ng/L of the latter.No sewage outfall pipe had a level below 2500 ng/L.

If you're wondering what the normal background for BT and TT is, the answer is, um, zero. All of the BT and TT found in all waters, sewage outfall, rivers, oceans, and drinking water samples is anthropogenic, man made.

Based on an analysis of the use of dish washing detergent, and the actual formulations themselves in the UK, the authors make a stab at understanding the likely limits of various sources, including the influent to sewage treatment plants (they actually measured discharges into the environment. An estimate for non-treated sewage is on the order of 15,000 ng/ml.

Of course (or maybe not of course), measurement and detection is meaningless absent a risk assessment, hopefully not one conducted by scientifically illiterate journalists at the New York Times. The authors have this to say about the risk associated with BT and TT:

Although the presence of chemicals in the environment and drinking water does not in itself pose a risk to health and the environment, there is concern that the possible effects of long-term exposure to individual chemicals and/ormixtures of chemicals are not fully understood.32,33 The implications of our findings depend to a large extent on the degree of (eco)toxicity of BT and TT. As stated in the Introduction, there appear to be gaps in knowledge, as a consequence of the lack of any chronic ecotoxicity data for fish and for the range of toxicity end points evaluated,16 of particular importance for these chemicals in relation to exposure... ...Although the presence of chemicals in the environment and drinking water does not in itself pose a risk to health and the environment, there is concern that the possible effects of long-term exposure to individual chemicals and/ormixtures of chemicals are not fully understood.32,33 The implications of our findings depend to a large extent on the degree of (eco)toxicity of BT and TT. As stated in the Introduction, there appear to be gaps in knowledge, as a consequence of the lack of any chronic ecotoxicity data for fish and for the range of toxicity end points evaluated,16 of particular importance for these chemicals in relation to exposure...

The authors then refer to some of what I said in my introduction:

Although there seems to be no particular reason to think that BT and/or TT will have a high acute:chronic ratio, and hence be of more concern than appears to be the case based on acute ecotoxicity data, caution should be exercised for the following reason. Many azoles are very active chemicals,with specific modes of action: many (imidazoles and triazoles) are fungicides used in agriculture, and others (e.g., fadrazole) are used for antiestrogen treatment in diseases such as breast cancer.36 Recent results have demonstrated that many commonly used fungicides act as endocrine disrupters in vivo in both mammals37 and fish.38. Structural alerts such as these can be useful in aiding the selection of appropriate chronic toxicity tests that should be helpful in determining whether BT and/or TT are significantly more toxic chronically than they are acutely.

The authors note that a Dutch Study implied that BT is a genotoxic (mutagenic) human carcinogen.

Adding further uncertainty to the toxicity of BT and TT is the possibility that BT is a human carcinogen. A Dutch committee39 concluded that the weight of evidence indicated that BT may be a possible genotoxic carcinogen, although it was highlighted thatv the database was inconclusive. Based on that assessment, and structural analogy, Australian drinking water quality guidelines suggest a maximum permissible concentration of TT of 7 ng/L.40 Given this uncertainty, it could be strongly argued that the Precautionary Principle should be applied to both BT and TT, and exposure concentrations (to both aquatic wildlife and humans) should be minimized until appropriate chronic toxicity data become available on which to base any risk assessments.

Note that the routinely found levels of these compounds were several thousands of times the regulatory limits allowed in Australia.

Have a nice evening.

(This diary was originally posted, a few hours ago, on Daily Kos along with an amusing poll. The Link Is Here.> - NNadir)