Foam at Natural Dam

Waterfall Glenn in Darien, IL is an ecologically diverse forest preserve in the DuPage County. Rocky Glen waterfall is a popular attraction within the forest preserve. I visited this waterfall over spring break, and there was a brownish/tan foam-like layer at the top of the waterfall as pictured above. At first this looked concerning, however upon doing research I found that this is generally a natural process. This foam is created when a surface-active agent, a surfactant, reduces the surface tension of the water. The air matrix allows for cohesiveness between the particles to be trapped into tiny bubbles where there is turbulence in the water. Natural waters contain organic matter, such as algae, plants and leaves from the trees that line the water body. When these organic matter degrade and decompose, they release cellular products, or another form of surfactant, into the water which reduces the surface tension of the water. The natural surfactant is termed dissolved organic carbon or (DOC) because of the decomposition of the organic matter. Wind blowing on the water surface disrupts the surface agent thus transforming it into a foam. Foam is naturally occurring in waters with high organic content, and it is a normal part of the ecosystem. Natural foam does not harm any plant or animals. Foam caused by dissolved organic carbon often occurs along multiple spots in a river or water body. Natural Foam has a relative earthy aroma and may have an off-white, tan or brown color. Upon doing more research on natural foam, I came across man-made surfactant. Man-made surfactant can also reduce the surface tension of water which can produce unnatural foam. Unnatural foam will have a perfume smell and is usually more white color. This unnatural foam can be disastrous for many habitats because it pollutes their water and the aquatic culture. In the past, there have been foam problems caused by synthetic laundry detergents. These laundry detergents were highly resistant to chemical breakdown, and therefore only slowly broken down by bacteria. Fortunately, it is now required by law that the foaming agent of all detergents must be biodegradable. Other causes of unnatural foam in the water may be due to personal care products such as shampoo, toothpaste, and chemicals used in the industries which also reduces water surface tension, allowing these product to easily mix with water therefore indicating pollution. Many household cleaning products comprise these man-made surfactants. A common chemical in these house-hold cleaning products is linear alkylbenzenesulfonates, commonly listed as sodium or ammonium laureth or lauryl sulfate. Contaminations of the waters due to the man-made surfactants is an important issue that needs to be addressed more because we are using these products daily. A safer alternative to using a sudsier product is a natural alternative that doesn’t produce unnatural foam, or contain chemicals that are not easily biodegradable. It is important to understand how the effects of our daily household cleaning products as well as toiletries can become detergent pollution and unnatural foam.

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