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ConditionsDishing the Dirt on Dishwashing Liquids

Dishing the Dirt on Dishwashing Liquids

Dishwashing detergents have never looked prettier or more harmless

Dishwashing detergents have never looked prettier or more harmless. They now come in such bright colours, with added fragrances and lyrical names such as Natural Extracts Aloe Fresh, Citrus Burst, Floral Breeze and Purple Herbal. But what's actually inside of that squidgy plastic bottle by your kitchen sink?

Think of the things these detergents have to cope with: congealed food, burnt-on grease and oils of all kinds. A quick sluice under the hot-water tap clearly isn't enough-what's needed is a serious bit of cleaning. The answer, according to the dishwashing-liquid industry, is to use a cocktail of industrial chemicals.

Heading the list of ingredients in dishwashing liquids are substances called 'surfactants'-short for 'surface active agents'. As the name implies, these are chemicals that can affect surfaces-in this case, the surface tension of water. Surfactants work by allowing water molecules to attach themselves to substances, such as grease, that are normally not soluble in water. The manufacturing industry uses surfactants fairly widely as degreasers, and what's in your bottle of Palmolive or Fairy Liquid is essentially no different. It's just that there's less of it in a bottle than in a car-manufacturing plant.
What are the names of these surfactant chemicals? Proctor & Gamble, manufacturers of the leading brand in Britain-Fairy Liquid-doesn't say anywhere on its labels, but Unilever does come clean on their Persil product. In this case, the top three surfactant ingredients (after water) are magnesium laureth sulphate, sodium laureth sulphate (SLES) and cocamidopropyl betaine. The first is not known to be toxic, but SLES can be carcinogenic when combined with other chemicals. It can also harbour the extremely harmful compound 1,4-dioxane, one of the principal components of the chemical defoliant Agent Orange. This may explain why SLES has been found to cause harm to human fibroblast cells-the most numerous cells in the body-inducing "membrane damage" with negative effects on fibroblast protein synthesis (Int J Cosmetic Sci, 1995; 17: 27-43).

In the US, despite tougher consumer regulations, Proctor & Gamble, which makes the brand-leaders Joy, Ivory and Dawn dishwashing liquids, can still get away with not declaring their ingredients-"biodegradable anionic and nonionic surfactants" is all they tell us. What are they trying to hide? Possibly the revelation that their surfactants are petroleum-based and may contain alkylphenol ethoxylates, which are suspected of being hormone disrupters even at small doses (Ann Occup Hyg, 2003; 47: 441-59).

Skin problems are another potential hazard of surfactant chemicals. Thirty years ago, SLES was shown to be a mild skin irritant (Drug Chem Toxicol, 1978; 1: 305-24). Cocamidopropyl betaine is, if anything, somewhat worse, causing "allergic contact dermatitis", according to a number of clinical reports (Am J Contact Dermat, 2001; 12: 223-4).

Yet, none of this should come as any surprise. After all, surfactants are degreasers, and the manufacturers need to choose those that are powerful enough to shift foul grease while, at the same time, 'protecting' your hands, the skin of which contains healthy, natural grease.

Ironically, many companies have, in the past, promoted the idea that their products were particularly gentle to the hands. Fairy Liquid's slogan used to be 'Hands that do dishes can be soft as your face'. Interestingly, Proctor & Gamble doesn't make that particular claim anymore-possibly because surfactants that are harsh on grease to be effective at dishwashing simply cannot also be soft on the hands.

Another consideration is what happens to the surfactants after they've disappeared down the drain. Many are derived from petrochemicals and persist in the environment. A 2001 in-depth study (Environmental Project No. 615) by the Denmark's Environmental Protection Agency discovered that, although most surfactants biodegrade in the air, they can accumulate in fish, causing potentially serious damage. According to the report, "Typical surfactants are toxic to aquatic organisms."

Some of the more minor ingredients in the typical detergent cocktail are styrene-acrylate copolymers, included in the mix as emulsion stabilizers. These chemicals were once considered harmless but, in a recent study testing the compounds on animals, it was found that they caused cancer when applied to the skin at a concentration of 21 per cent as well as severe skin irritation (Int J Toxicol, 2002; 21 [Suppl 3]: 1-50). Although these effects may not apply to humans, this could be why most detergents display the caveat-albeit in small print-to "avoid prolonged contact with the liquid and washing solution", or "wear protective gloves".

Also, be aware that you probably won't be scrupulous about washing all of the detergent off your crockery, which means that you may end up eating it. Styrene, for example, is toxic enough to have an official safety limit of 50 ppm (parts per million), and its list of side-effects is head-spinning-literally-as it can cause headaches, lassitude, dizziness, confusion, drowsiness, unsteady gait, narcosis, possible liver injury and reproductive effects, to name but a few (National Institute for Occupational Safety and Health (NIOSH) Pocket Guide to Chemical Hazards, Publication No. 2005-149, 2005; September).

Squeaky-clean alternatives?

Fortunately, there's now a rapidly growing range of washing-up liquids for the safety-conscious consumer, all claiming to be 'green', 'natural' and some even organic. But are these alternatives all they're cracked up to be?

One thing that frankly shocked us in our survey is that some of these so-called ethical dishwashing products fail to live up to their credentials. Indeed, top names and top pricetags are no guarantee of top-notch ingredients.

Another fact to bear in mind is that 'natural' doesn't always mean safe. For example, the most common natural source of surfactants is coconut oil and, although most coconut-derived compounds are harmless, the two that are decidedly not are cocamide DEA and cocamidopropyl betaine, both known to be skin irritants (Contact Dermat, 1999; 40: 98-103). Worse, cocamide DEA may cause cancer, as it can form nitrosamines, chemical compounds known to cause lung and liver cancers, among others (Cosmetic Ingredient National Library of Medicine. HazMap: Occupational Exposure to Hazardous Agents Review Assessments, 2006).

PROOF! has tested five of the leading 'green' washing-up liquids available in the UK, asking one main question: are the ingredients safe-and not only safe for us, but also for the environment? We also wanted to know how well they work (in fact, they all worked well), and whether they are good value for money.


Natural Almond
Earth Friendly Products;; tel: 01892 616 871
Price: lb3.40 for 739 mL (Greenbrands has various offers)
Rating: *****

Dishmate is so proud of the quality of its product that it claims that "it can be used as a liquid hand soap and bath/shower soap", and even "softens hands while doing dishes"-pretty impressive calls for a mere dishwashing liquid. How do they do it? The answer is in the very short list of ingredients, most of which are botanicals. The surfactants it uses are all derived from coconut oil, and Dishmate says that they have taken care to exclude cocamide DEA. It also contains almond and cherry oils for fragrance and skin care-and that's it. The only non-plant ingredients are salt and water.

In use, it performed as well as the usual, toxic commercial brands. In addition, the product works out at 0.005 pence per mL, making it the second least-expensive product in our survey-but good value for money given its top-notch quality.

with lemon and aloe vera; tel: 08451 302 230
Price: lb1.11 for 500 mL
Rating: ***

One of the first manufacturers of household products to go eco-friendly, Ecover has an unrivalled reputation in the environmental movement. However, this product is not their most shining example. Its main active ingredient is the highly questionable sodium laureth sulphate (SLES; see text above), a fact not disclosed on the product label, but only on the company website.

Another curious ingredient is the preservative 2-bromo-2-nitropropane-1,3-diol, an old-fashioned chemical currently being phased out of cosmetics and toiletries because it produces highly toxic and cancer-causing nitrosamines. Also, when it comes into contact with water, it produces formaldehyde, another potential cause of cancer. It also becomes a problem for those with allergies as it can irritate the respiratory system and cause other unpleasant symptoms such as nausea, headache, diarrhoea, nosebleed, fatigue, dizziness and memory lapses. Higher exposures may even be life-threatening. Admittedly, this chemical compound comprises only 0.02 per cent of the product, but it's yet another dent in the product's prestigious 'green' image.

Nevertheless, our panel of testers thought that it cleaned better than most of its rivals. As for cost, the product works out at 0.002 pence per mL, making it slightly cheaper than our top-ranking product.

Faith in Nature; tel: 0161 724 4016
Price: lb1.95 for 1 L
Rating: ***

"Unlike the majority of modern washing-up liquids, Clear Spring is vegetable-based, using very mild detergents, which are 100 per cent vegan, biodegradable and with minimal environmental impact," says Faith in Nature. However, if you drill deep enough into their website, you will discover that the principal ingredient is the surfactant ammonium laureth sulphate (ALES). Although derived from coconut oil, ALES is a mild skin irritant, as discovered by the US military, which has tested ALES as a 'less-than-lethal weapon', using its profuse production of foam to disperse a hostile crowd, as reported by the Sandia National Labs in Albuquerque in a 1995 report on applied studies for military technology, weaponry and the national defense.

Clear Spring also contains the preservative 2-bromo-2-nitropropane-1,3-diol (see Ecover above)-again admittedly only in minute doses, but which nonetheless belies the product's positive environmental image.
However, our testers thought it worked well, with a little going a long way. In terms of cost, the product works out at 0.002 pence per mL, making it the same as Ecover's offering.

Shadow Lake Inc.;; tel: 0207 289 2121
Price: lb5.80 for 1 L
Rating: **

"Citra-Dish liquid is a natural sink-side companion that is perfect for hand-washing-and for washing hands!" says the manufacturer, Citra-Solv LLC. That claim might well be true if you go by the declared ingredients, which are listed as "natural cleaning agents (coconut and vegetable-based)". However, when PROOF! asked Citra-Solv to specify what these agents actually were, we were told that they included the surfactants fatty alcohol ethoxylate, alkyl glucoside and . . . sodium laureth sulphate (SLES). So, full marks to Citra-Solv for honesty (albeit when pressed), but not for environmental friendliness: although Citra-Solv claims the product has "no damaging petroleum distillates", fatty alcohol ethoxylate is "highly toxic [to] aquatic organisms" (J Am Oil Chem Soc, 1996; 73: 929-33).

Another questionable claim the company makes is "no animal testing", which is misleading. The product itself may not have been tested on animals, but virtually all the ingredients it uses will have been-if only by official regulatory bodies. Citra-Solv tells us it is currently "in the process of reformulating" the product.

In terms of monetary cost, the product works out at 0.006 pence per mL, making it the second most-expensive product in our sample.

Natural House; tel: 0115 960 4038
Price: lb5.15 for 500 mL
Rating: **

A very expensive product-at 0.010 pence per mL, the most expensive offering in our sample-Dish Spa's major selling point is that many of the ingredients are organic, perhaps rather extravagant for something that may go down the gullet in tiny quantities. The major surfactant ingredient is potassium cocoate, derived from coconuts and thought to be non-toxic. In the small print, the manufacturer also discloses that it uses less than 5 per cent "anionic" and "amphoteric" surfactants that are "both plant-derived", but without specifying either the plants or the names of the chemical compounds referred to. Sunflower and palm kernel oils are other botanical ingredients. The only dubious one is benzyl alcohol, a preservative that has been found to be neurotoxic (Lancet, 2006; 368: 2167-78) and allergenic and, thus, only permitted in small doses.

As a washing-up liquid, our testers found it unsatisfactory, as the lack of foam and the way it clouded the water gave no clues as to how much product was needed for it to work.

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