As you may have noticed, the dishes and glassware have been “dirty” recently. You may think that your dishwasher is failing and needs to be replaced. – Wait, it’s not your appliance, it’s the detergent.
The new law
Without much fanfare, governments recently decided to ban phosphate entirely in detergents, such as those used in dishwashing materials. For many years, phosphate has been a vital component of laundry and dishwashing detergents at a concentration of about 0.5% (P, phosphorus). Now, new laws and regulations prohibit it completely. Just look at the writing on a recently purchased box of the stuff; It says “phosphate free”. Why this change?
What is the problem with phosphate?
Phosphate is one of the key nutrients for plants. Any plant fertilizer you buy contains some (the concentration usually given by the third of the three numbers on the package). Phosphorus is widespread in nature (but is only found as salts of its oxide, called phosphates), in fact it is about five times more common than carbon in the earth’s crust. Phosphate is also vital for humans. For example, our teeth and bones are largely made up of a phosphate salt, called apatite.
Before about 1970, most detergents contained what might be called “liberal” amounts of phosphates. Additionally, there were few, if any, municipalities that treated wastewater to limit phosphate in their effluents. This caused a generalized overfertilization of the water bodies that receive these effluents. They became “eutrophic” (well fertilized) or “hypereutrophic” (over fertilized) with algal blooms forming a visible scum on their surface. Later each season, the algae died and sank to the bottom. Its slow decomposition would consume the oxygen in the bottom water and cause oxygen depletion, resulting in the death of bottom-dwelling organisms. Lake Erie was a prime example of that. He was declared “dead” in the early 1970s.
The cause and consequence of “dead” lakes were soon discovered, namely excessive fertilization with phosphates. This led to the US-Canada Great Lakes Water Quality Agreement, signed by President Nixon and Prime Minister Trudeau in 1972, and accompanying regulations. Effluent from cities like Detroit and Windsor, and all other riverside communities, had to be treated to remove excess phosphate, up to a limit of one microgram of phosphorus (P) per liter of effluent. Sewage treatment plants were built, started operating, and fifteen years later, voila, Lake Erie was no longer “dead” and was once again teeming with large walleye and other fish populations.
Of course, phosphate in wastewater doesn’t just come from detergents. In fact, a significant proportion comes from human waste flushed down the toilet. However, to facilitate faster regeneration of natural systems, before all the new wastewater treatment plants were fully operational, another type of phosphate control was simultaneously established. That was to replace much of the phosphate in common detergents with some substitute materials. At that time, nitrilotriacetic acid (NTA) was found to be the material of choice and has been a key ingredient in most detergents ever since.
Fast forward to 2011
The system of limiting phosphate in detergents to 0.5% (P) worked well for about 30 years. Wastewater treatment plants are removing excess phosphate to the required level, and lakes and rivers no longer receive an overabundance of nutrients.
Depending on the hardness (level of calcium and magnesium ions) in the local water, your detergent requires different amounts of P, NTA, and other materials. Detergent manufacturers know this very well and adjust the composition of the detergent to local conditions. In fact, some also foresee seasonal variations in the composition of the detergent.
In 2010, several politicians decided that if 0.5% (P) is good, then 0.00% (P) must be better [1]. So why not ban it outright? Indeed, that was what happened. And that’s why your glassware no longer sparkles and may still have food particles stuck to it when you take it out of the dishwasher. For example, even Procter & Gamble acknowledges that its new phosphate-free detergent formulation may result in “filming” and apologizes. [2]. Of course, they also offer a new “anti-filming” product.
Despite the use of strong complexing agents, such as NTA, a small amount of phosphate in the detergent makes your glassware sparkle. Frankly, I’m not exactly sure of the mechanism, but the fact is indisputable. So, with the total ban on phosphate now, the shine of your glassware has been replaced by streaks and dull-looking surfaces that may also have food particles attached to them.
Of course, wastewater effluents are still treated to the 1 microgram (P)/L limit anyway. So, if the sawmill treatment plant influential has, say, 5 or 10 micrograms (P)/L really shouldn’t make any difference to the phosphorus concentration of the effluent.
Therefore, banning phosphate entirely from detergents does not make sense in jurisdictions where wastewater is treated to a common phosphorus standard, such as all US states and Canadian provinces bordering the Great Lakes. In total, a population comprising approximately 50 million people in the US and Canada is affected by this new rule for no good reason.
What can you do?
As a consumer and taxpayer, you can contact your political representative(s) and urge the new ban on phosphate in household detergents to be revoked. Or you can buy an “anti-film” product (but it may not help remove food particles). You can also use a commercial grade detergent, or you can buy some widely available phosphate salt for other applications and mix it with your regular detergent.
Copyright © 2011, Dr Klaus LE Kaiser