Detergents are cleaning products manufactured from synthetic chemical compounds, as opposed to soap, which originates with natural substances like lye and plant saponins. Detergents figure in an extensive array of industrial and home cleaning applications, including laundry and dishwasher detergents. Released into the flow of wastewater coming from the home, these detergents can have far-reaching environmental impacts.

Phosphate Nutrient Loading

Phosphate-containing detergents can create algae blooms in fresh water. These in turn use up the oxygen available for aquatic life, according to Lenntech, a water treatment facilities corporation affiliated with the Technical University at Delft, the Netherlands. This problem occurs because phosphorous and nitrogen from detergents are nutrients that stimulate excessive growth of algae and other aquatic vegetation, reports the Indiana University News Room. Nutrient loading with phosphates from laundry and dishwasher detergents, as well as from suburban lawn chemicals, can lead to eutrophication, a process by which a freshwater aquatic ecosystem slowly dies due to continual oxygen depletion. Phosphate-containing laundry detergents are banned in most states, and about a half-dozen states have banned phosphate-containing dishwasher detergents as of mid-2010.

Surfactant Toxicity Increase

Surfactants, or surface-active agents, are chemicals that reduce the surface tension of oil and water; in detergents, surfactants help dirt to drop out and stay out of clothing or other items being cleaned. Surfactants in detergents are toxic to aquatic life, persist in the environment and break down into additional toxic byproducts, according to the U.S. Environmental Protection Agency. In a freshwater environment, surfactant-containing detergents break down the protective mucus layer that coats fish, protecting them from parasites and bacteria, according to Lenntech. The reduced surface tension of water also makes it easier for aquatic life to absorb pesticides, phenols and other pollutants in the water. The EPA also advises that surfactants can disrupt the endocrine systems of humans and animals; Lenntech notes that surfactants decrease the breeding rates of aquatic organisms.

Packaging

Laundry and dishwasher detergents come in plastic containers that are generally non-reusable and non-recyclable, according to the EPA. The volume of detergent packaging heading to landfills, given the weekly purchase of detergent-based household products by a significant portion of consumers, creates an enormous environmental impact. The European branch of the International Association for Soaps, Detergents and Maintenance Products announced in 2009 an industry-wide initiative to reduce detergent packaging by manufacturing smaller packages of more concentrated detergent products. American consumers have also noticed smaller laundry and dishwashing detergent packages on their supermarket shelves. The industry association notes that, to be successful, this packaging-reduction strategy will require consumers to carefully read the labels and cut down on the quantity of detergent used; significantly less is required for the same cleaning ability because of the new concentrated formulas.

There is an endless variety of cleaning products. To assess their actual impact on the environment, a full analysis of their life cycle would have to be carried out: production, packaging, transportation, use, disposal and recycling.

It is not easy to establish the overall environmental impact of a given product. We know more about the polluting effect of detergent after their use when, discharged into sewers, they end up in the environment through the streams and infiltration. 

A significant effect on water quality

Since they are used on a large scale, detergents are partly responsible:

• for eutrophication of rivers: 
The phosphorus and nitrogen compounds in detergents get concentrated in rivers. These two nutrients enable increased growth of aquatic plants (algae) that invade the entire aquatic area. When plants die, their decomposition consumes oxygen from the aquatic environment. Added to this is the consumption of oxygen due to the decomposition of the surfactants present in the detergents. Fish and invertebrates do not find adequate oxygen and die by asphyxiation. All this contribution of organic matter continues to decompose nevertheless but this time without oxygen. This is anaerobic fermentation that releases hydrogen sulphide and that smell of "rotten eggs";

• for the contamination of groundwater by contributing nutrients (surfactants) and mineral salts such as phosphates, nitrates, ammonium, boron, etc.;

• for the decline of coastal plants subjected to polluted spray;

• for the cloudy water phenomenon. Very surprising in the late 50s when large foam ponds due to excessive foam appeared on rivers. It was the alarm bell!

• for the disturbance of aquatic organisms:

o When not treated fully in water treatment plants, the surfactants in detergents affect the natural defences of these organisms (their skin, scales, shell, walls of the plants or the bacteria) against chemical substances and pathogens. 
o Finally, some surfactants such as ethylene glycol disrupt the hormonal system of aquatic animals.

Reduction of impact is in process

Fortunately, the law has developed considerably since the 70s. EU rules have been progressively strengthened.

Current legislation calls for:

• an obligation to treat waste water;
• a ban on foaming surfactants;
• facilities for placing biodegradable products on the market;
• enhanced biodegradability requirements.
Currently, the biodegradability criteria of surfactants are derived from the European EC 648/2004 regulation(link is external). All surfactants must degrade more than 60% in 28 days under aerobic conditions.

However, a large room for improvement is still possible. The FAQ will tell you more about it.

FAQ

Biodegradable surfactants, really?

This new standard of rapid degradation of the surfactants is a real improvement over previous requirements. However, it can be further improved. 
On the one hand, biodegradability is measured at 28 days and in the presence of air. During this time, molecules of the surfactants have ample time to escape from sewage treatment plants and spread in the environment. Some surfactants are strongly attracted to limestone and tend to settle in the sediment at the bottom of rivers. Thus imprisoned, they degrade with greater difficulty.

On the other hand, the level of optimal biodegradability of 60% in 28 days is not ideal. Even though 60% of the degraded product is in the form of carbon dioxide and water, in what form is the remaining 40%?

Finally, tests are conducted on each individual component. However what is required is the biodegradability of the complete product. In addition, tests are conducted under very different conditions from those that exist in the environment (temperature, salinity, biological activity). Laboratory results show little of what is actually happening in the environment and this is the real difficulty of carrying out these tests.

Therefore, there is still room for improvement. New generation products are now made with 100% biodegradable surfactants (in 28 days). Industries are developing less toxic products. Most successful formulae from the viewpoint of their efficiency and the environment can get the European Ecolabel(link is external).

And phosphates?

Phosphates are non-toxic by themselves. In fact, phosphorus is an element necessary for living organisms and even a limiting factor that determines the amount of life that can develop in a given habitat. Excess phosphate causes proliferation of plant organisms and aquatic plants. It is the cause of eutrophication. Highly eutrophic waters, i.e. rich in organic matter, are very poor in oxygen, and not very favourable to biodiversity. In addition, they promote the proliferation of pathogens.

In Belgium, phosphates are prohibited in household detergents since 2003. This standard has been applicable throughout Europe since 1st July 2013. In 2017, this ban will also cover products for dishwashers.

It is important to note that phosphates perform several essential functions in detergents that contain them. They must be replaced to ensure effectiveness of the detergents. These alternative substances must also be evaluated to ascertain whether the elimination of phosphates is really benefiting the environment and poses no health problems.