Do conventional shampoos have an impact on the environment?

environmental impact of conventional shampoos

The people who lived before the 20th century found it incredibly hard to believe that anything human beings do could ever impact on the environment. The skies seemed too infinite, the oceans too vast and the multitudes of animals too resilient to ever be affected by little old us. Now of course we know better (cough cough). Powerful philanthropists like Al Gore and Leonardo Dicaprio have informed us about the ways in which our use of fossil fuels is pushing us towards a doomsday that will make the ending of Titanic look like a Pixar movie.

And yes, even shampoos make it onto the “no buy” list because of some of the harsh chemicals found inside their plastic bottles. The offending ingredients are the detergents which are responsible for their cleaning properties. The environment is impacted when these detergents go down the drain and onto the heads of innocent ninja turtles. Let us take a moment to count the many sins of these products.

Cry me a river

Detergents are comprised of a lot of phosphates and nitrates which can be harmful if they reach our rivers. These nutrients enable accelerated growth of aquatic plants (like algae) and in so doing threaten to overrun the aquatic ecosystem. When these plants die, large amounts of oxygen are extracted from the water during the decomposition process. This has the knock-on effect that fish and invertebrates in the water may be starved of oxygen, ultimately resulting in their asphyxiation. This matter doesn’t stop decomposing though — but now it has to do so without oxygen. Once that point is reached then hydrogen sulphide is released into the water, leaving a putrid “rotten eggs” smell in the air.


Detergents are made up of surfactants which are essentially chemical agents that diminish the surface tension of oil and water. This property is hazardous to aquatic life, according to the U.S. Environmental Protection Agency, in that surfactants weaken the mucus layer around fish that protects them from parasites and bacteria. The reduction in surface tension in the water also increases the likelihood that the aquatic life could absorb pesticides, phenols and other harmful substances flowing into the river. Eventually this reduces breeding rates.

Biodegradable surfactants to the rescue …. sort of

Many manufacturers have thankfully decided to move away from undesirable surfactants in their products, opting instead for biodegradable versions. The question is: Are these detergents much better for the environment?

To answer that question one has to keep in mind that biodegradability is measured in 28 day cycles. The problem is that molecules have plenty of time within that window to escape from sewage treatment facilities and spread into the environment, possibly giving rise to the algae bloom described above. Also, some surfactants are highly attracted to limestone and will tend to settle at the bottom of rivers. Caked in sediment, it becomes more difficult for them to break down.

Furthermore, some of the other standards of biodegradability are less than convincing. For one, currently it is only required that 60 percent of the product degrades within 28 days. And even if 100 percent were accounted for, there would still be the problem of testing. A lot of the inspections are done in laboratories — under very different conditions to those that exist in the environment. The temperature, salt content and biological activity can all vary greatly out in the field such that it is hard to trust fully in test results.

Bottom line

Though several studies have shown that surfactants are not overtly hazardous to the environment when regulations are strictly followed, there are many reasons to be dubious of choosing surfactant-based shampoos. Plant-based alternatives are surfactant free and avoid many of the risks described above. Also, the ninja turtles will thank you for your contribution to a healthier sewer.

Photo by Jackson Jost on Unsplash