Doing the laundry again? In a half-hour, 35 gallons of detergent-laden water will have cascaded down your drain. Have you ever wondered exactly what is in those liquids or powders that you contribute to the great outdoors every week, courtesy of your wash water? 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.
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.
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, and that is how I'll use the term here.
Phosphates are added to detergent as "builders," so called because they build up the effectiveness of the surfactant. 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 for half an hour?
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, 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.
