Dear Umbra,
Why haven't phosphates been removed from
dishwashing detergents like they have been from laundry detergents? I
know they make your clothing look brighter, but what do they do for
dishes?
Natalie Waddell-Rutter
North East, Pa.
Dearest Natalie,
Phosphates in dish detergent do a few nice
things for dishwasher-washed dishes. Their biggest contribution is that
they essentially soften the effects of "hard" water, combining with the
minerals in it, mostly calcium and magnesium, thereby eliminating the
spots and film on dishes that can form when the minerals and food bits
combine during the wash. Phosphates also make the water's pH more
alkaline, which can help in food-bit removal.
This is also basically what phosphates did for
clothes in the clothes washer, essentially making the detergent more
effective by getting the minerals out of the way. But that was back
when laundry detergent companies in the U.S. still used phosphates. Now
they don't.
Which brings us to your question.
Back in the 1970s, the U.S. government
recognized the problem of phosphorus pollution -- it can cause massive
algal blooms in waterways that screw with ecosystems by robbing the
water and aquatic life of all-important oxygen -- and started trying to
come up with alternatives. Meanwhile, states and localities became more
and more aware of the undesirable effects of phosphorus and began
acting on their own to limit or restrict its use in laundry detergents,
the first places being five cities in Illinois in 1971. (Way to go,
Illinoisans!) By the 1990s, enough states and localities had limited or
restricted laundry-detergent phosphates that detergent companies saw
the writing on the machine and decided to voluntarily phase them out in
all domestic formulations, which was done by the mid-1990s.
The main reason dishwashing-detergent
phosphates didn't get the same treatment was that the best
alternatives, enzymes, were neither common nor cheap even as late as
the early '90s. There was also the influence of heavy lobbying by
detergent makers and
phosphate cheerleaders to keep them in. And so phosphates remain in many detergents at varying levels, even though they don't need to be there.
There are plenty of eco-friendly,
phosphate-free alternatives that wash dishes just as well or better
than phosphate-laden ones. And you probably won't be surprised to learn
that mainstream, big-name detergents have lots of other suspect
ingredients that are derived from petroleum and aren't so
environmentally benign, a main one being artificial fragrances. So it's
best to use one of the eco-brands anyway, and any eco-brand worth its eco-label will be phosphate- and chlorine-free.
Some states and localities
are starting to severely limit or ban phosphates in dishwasher
detergent too. My spiffy home state of Washington
signed new rules into law this year
that will keep the phosphorus content in dishwashing detergent to 0.5
percent beginning in 2010. It's a significant cut, since detergents now
contain up to 9 percent.
The soap we use to wash dishes by hand doesn't
contain phosphates, but don't get any bright ideas about using it in
your dishwasher. I did that once, and suds oozed out the sides and all
over the kitchen floor.
Spotlessly,
Umbra