Medicating the oceans

Medicating the oceans

I bet you never think about the fish when you flush your toilet. But studies have shown that a range of drugs and chemicals used by humans ends up travelling through the sewer system and into the sea, where it affects marine life.

A team of researchers at the University of Portsmouth in Britain recently tested waste water flowing into rivers and the sea and found high levels of fluoxetine, the agent used in the anti-depressant drug Prozac. They then exposed shrimp to the same concentrations of the drug they found in the waste water and it drastically affected the behaviour of the shrimp.

Shrimp are normally attracted to dark, safe areas, but the shrimp exposed to Prozac were five times more likely to swim toward a bright region of water, which would leave them exposed to predators. The traces of Prozac that make it into the sea could seriously upset the natural balance of the ecosystem.

Scientists have also found that Prozac is linked to behavioural changes in other species. It causes female freshwater mussels to prematurely release their larvae, which reduces their chances of survival. It has also been shown to delay the sexual maturity of fish and frogs.

The use of anti-depressant drugs has soared in recent years, and users excrete them into the sewage. Yet the environmental effect of this on wildlife is only now being researched. Other common drugs we use every day, such as painkillers, can also cause problems for sea creatures.

Illegal drugs such as cocaine, heroin, marijuana, and ecstasy, are also released into waste water through a person's urine and faeces, and traces of these drugs have been found in many bodies of water near major cities.

Scientists in Washington State, on the west coast of the US, have also found traces of cooking spices and flavourings in the sea water.

They can even notice the difference in the water according to the foods we eat at certain holidays. For example, the herbs thyme and sage are detected during Thanksgiving because they are used in special holiday dishes. Scientists are still trying to learn what impact these spices have on sea life.

The scientists say that sewage treatment plants need to break down the drugs before pumping waste water into the sea, and people need to be more careful of how they get rid of unused drugs.

Our actions can affect animals and fish without us even realising it. While we use chemicals and drugs to make our lives easier, they may not be as good for sea life. Shrimp can't say no to drugs if we put them in the water.

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