Detergent Phosphates

• Today's biodegradable detergents contain phosphates, among other things. The phosphates are "builders," which help the detergent to work more effectively in the hard water found in most areas by binding to the ions found in hard water and removing them. It is the phosphates found in these detergents that cause environmental harm. Wastewater treatment is able to remove up to 90 percent of the phosphates in wastewater, making sewer drains or sinks the best place to dispose of detergent water.
  
  

Algae Production

• Phosphates from detergents create a free form of phosphates when they combine with water. The free phosphates from detergent mix with the phosphates found from natural sources such as pet waste and vegetation. Phosphates ire a necessary part of a healthy water ecosystem, but when there is too much phosphates in the water, it encourages the overproduction of algae, who feed on it. The thick cover of algae in the water blocks the sunlight required by the photosynthetic organisms and bacteria that keep the water clean. Lack of sunlight also fosters the growth of unwanted weeds.
  
  

Decomposing Microorganisms

• Algae are a food source for microorganisms that help in the decomposition of solid matter, and their numbers increase with the increase in algae caused by phosphates. These microorganisms use oxygen as an energy source, so too many of these microorganisms in a body of water depletes the oxygen supply. This means there is not enough oxygen for fish and other aquatic life, causing them to die. Animals higher up on the food chain, such as birds of prey, cats and bears, lose this source of food, causing hardship and death among their numbers.
  
  

Toxic Algae

• Besides the damage that an oversupply of algae in a body of water can cause, some algae are additionally dangerous. There are toxic varieties of algae that even cause cancer, such as the blue-green algae known as cyanobacteria. These toxins are harmful to both animals and humans.
  
  

Phosphate-Free Detergent

• Phosphate-free detergents have negative environmental impacts as well. The binders that are used as phosphate alternatives--zeolites, nitrilotriacetate, alkyl phenols and sodium citrate--can have harmful effects on the reproductive system of aquatic animals. Alkyl phenols can mimic estrogen and damage the ability of these animals to reproduce. Some of the effects of these builder compounds remain in the environment even after treatment of the water containing it.