Detergents can enter marine ecosystems in various ways. However, detergent pollution primary occurs due to human activities. Let’s classify main pathways:

• Wastewater discharge: after detergents are used in households and industries, they reach waters that flow to the central treatment plant. If the contaminated water is not properly purified, detergents can leak into lakes, rivers, seas and oceans. 
• Boats and ships: detergents used for cleaning boats, ships, and offshore platforms are often discharged directly into the sea. 
• Surface runoff: detergents used outdoors, such as in agriculture, cleaning and washing activities, can be washed into water bodies by rain and melted snow.

As mentioned earlier, detergents contain phosphates, surfactants, and bleaching agents. These chemical components are very harmful to aquatic organisms. Phosphates are one of the primary contributors to nutrient overload in the sea, which can trigger the process of eutrophication, that contributes to algal bloom. In addition, the aggressive composition of detergents disrupts the mucus layer of marine organisms, thereby reducing biodiversity and fish population. 

Let’s explore each of these impacts in further detail:

• Eutrophication: the process of eutrophication is exacerbated by the phosphates found in detergents, which on average comprise 35% to 75% of their composition. When phosphates enter the ocean through detergents, they act as nutrients, fueling the bloom of microalgae and macroalgae. Excessive amount of algae bloom leads to oxygen depletion and reduces the sunlight penetration in the water. Furthermore, as a result of the decomposition of algae, even more oxygen is consumed, creating “dead zones”, where living organisms cannot survive. The resulting loss of oxygen disrupts the marine ecosystem, affecting the food chain, fish populations, plants, sea-grasses, and other organisms that depend on adequate levels of oxygen in the water.

Although many countries have introduced regulations on the quantity of phosphates contained in detergents, their composition still poses a great threat to marine ecosystems and aquatic life.

• Foaming: The foaming process occurs due to surfactants in detergents composition, which make up approximately 15% – 26% of their formulation. Surfactants reduce the surface tension of water, leading to the formation of foam when mixed with water on the surface of the sea. Thick layers of foam block sunlight, preventing it from reaching marine plants and organisms. Foam can also have harmful effects on marine life. For example, marine inhabitants can ingest foam, or it can destroy the protective mucous membranes of fish and other aquatic organisms, causing their death and a decrease in population. Reducing the concentration of surfactants in detergents is a crucial step in achieving and mitigating negative effects on the marine ecosystem.

• Aquatic toxicity: Bleaches found in detergents are highly toxic to marine life. Chlorine-based detergents can negatively affect the health of fish by damaging their gills. In addition, bleaches, such as sodium hypochlorite, can release chlorine gas into the water, which is highly toxic to marine organisms. Some bleach byproducts, like certain chlorinated compounds, can persist in marine environments and have long-term effects on marine ecosystems. For example, they can bioaccumulate in the food chain, reducing the immunity of marine life and causing reproductive failures. Furthermore, bleaches kill marine bacteria that are essential to the marine environment. These bacteria play an important role in nitrogen cycle, nutrient regulation, and represent the foundation of the food chain, making them essential for the health of marine ecosystems.

• Plastic pollution: Plastic packaging is commonly used for detergents and, due to improper disposal processes or limited recycling availability, it eventually ends up in landfills or in the ocean. As plastic degrades, microplastics are formed – tiny plastic particles that are less 5 millimeters in size. Ingesting small plastic particles can cause internal damage to the intestines and liver of marine organisms. In addition, chemicals present in plastics, such as plasticizers and stabilizers, can be toxic to marine life, because they can accumulate in organisms and be transferred up the food chain. 

Using biodegradable detergents that do not contain phosphates, surfactants and bleaches can help reduce the negative impacts of these products on marine ecosystems. Biodegradable detergents consist of plant-based components, that decompose quickly in nature, without negative consequences for the environment. 
When buying detergents, it is also essential to pay attention to their packaging: paper, cardboard, or recycled plastic are a great option. Refilling your container instead of buying a new one each time is also an effective way to minimize single-use plastic and packaging waste.

• Detergent Disposal into Our Environment and Its Impact on Marine Microbes | IOP Conference Series: Earth and Environmental Science https://iopscience.iop.org/article/10.1088/1755-1315/97/1/012030/pdf 
• What are microplastics? | National Ocean Service https://oceanservice.noaa.gov/facts/microplastics.html
• What is a dead zone? | National Ocean Service https://oceanservice.noaa.gov/facts/deadzone.html 
• How our detergent footprint is polluting aquatic ecosystems | • Down To Earth https://www.downtoearth.org.in/water/how-our-detergent-footprint-is-polluting-aquatic-ecosystems-77935 
• Liquid detergent composition | https://g.co/kgs/oFWPsyR 
• The pH Levels in your Laundry Products | A cleaner World
https://acleanerworld.com/blog/ph-levels-your-laundry-products