ENVIRONMENT : It All Comes Out in the Wash

Doing the laundry again? In half an hour, 35 gallons of detergent-laden water will have cascaded down your drain. Have you ever wondered what exactly is in those liquids or powders that you contribute to the great outdoors, courtesy of your wash water, every week? Is your laundry detergent safe for the environment?

Many modern detergents are a high-tech cocktail of chemicals. When you dump a cup of detergent into the water, you mobilize an efficient little army: Compounds that make the water wetter, disarm the calcium, disperse the dirt, control the alkalinity, make your clothes smell good and coat them so that they wash clean a little more easily next time. Some detergent formulas even make your clothes fluoresce a little in sunlight, so that they look, yes, whiter than white.

Most detergents are not very toxic, carrying a caution label, at most. However, according to Poison Control, they are responsible for more household poisonings than any other substance. Keep them out of the reach of small children.

The most important ingredient in any laundry detergent or soap is the surfactant, short for surface active agent. Surfactants reduce water’s natural surface tension, letting it wet surfaces more effectively. They remove dirt. And they dissolve oil and grease.

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Soap is a surfactant made from natural fatty acids, either from plant material, such as coconut oil, or from tallow, rendered animal fat. Soap has one major drawback: It does not work well in hard water, where it leaves a residue on the wash.

Most modern detergents use synthetic surfactants derived from petrochemicals. In fact, “detergent” generally refers to any surfactant other than soap.

Phosphates are added to detergent as “builders,” so-called because they build up the effectiveness of the surfactant. They do this by inactivating calcium and other minerals that make water hard. Builders also disperse dirt and maintain the alkalinity of the water. Other ingredients added to detergent may include bleach, fabric softener, stain-eating enzymes, perfumes and colorants.

What happens to all these ingredients after they sluice through your clothes?

Most of the major surfactants in use today biodegrade in the sewage treatment process. The fate of trace ingredients such as whiteners and colorants is not really known.

Phosphates are another matter. These chemicals are not removed by conventional sewage treatment processes. In some areas of the country, special chemicals are added during treatment to remove phosphates. If discharged along with treated water into lakes and streams, phosphates promote the growth of algae, clogging the water with more vegetation than it can handle. This speeds the evolution of lakes into swamps.

Because of this serious problem, phosphates are banned in laundry detergent in many states and communities.

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What else is in your laundry detergent? In Seattle, the water treatment utility recently asked the nonprofit group Washington Toxics Coalition to take a look.

One of the things the researchers looked for was toxic metals, such as arsenic, cadmium, chromium, lead and mercury, which earlier studies had found in high concentrations. These metals don’t biodegrade in water treatment. Instead, they concentrate in sewage sludge or are discharged with treated water.

The coalition didn’t find tons of metals but did find a surprising correlation: The more phosphates a detergent contained, the more arsenic it was likely to contain. In fact, the coalition calculated that if everyone used high-phosphate detergents, that would account for 20% of all the arsenic that comes down the city’s drain pipes--about 200 pounds of the deadly stuff a year.

(Detergent manufacturers don’t add arsenic to their product. The metal is simply attracted to the same materials phosphates are. When phosphates are mined from the earth, arsenic comes along, too.)

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What does this mean for the average launderer? Washington Toxics Coalition’s Philip Dickey (whose office is awash in cleaning products) suggests that, if you’re concerned about the environment, your best bet is to use as low-tech a phosphate-less laundry detergent as possible. Or just use laundry soap. And use the minimum amount called for by the manufacturer. In fact, try using a little less.

Liquid laundry detergents are all free of phosphates. However, most people aren’t able to recycle the big plastic jugs they come in. If you use a powder instead, look for one that advertises itself as phosphate-free.

Does this mean you are doomed to be dingy? Consumer Reports evaluated detergents in its July, 1987 issue and concluded that phosphates don’t make a huge difference in how clean your clothes get. Buy some enzyme stain remover and spot this on your clothes as needed. And cultivate a bias for cotton clothes. They are easier to clean.