Grateful for Clean Water
When I open a tap to fill my water bottle, I am grateful to live in a part of the world that offers this luxury. I am aware that not everyone can easily access clean water.
Wastewater and Pollution
Water pollution constantly requires attention in our urbanized world because wastewater can come from many households, businesses, and factories. This wastewater can contain various pollutants and contaminants, such as:
- viruses
- excess nutrients
- chemicals
- radioactive materials
- heat
To mitigate the negative effects, sewage treatment plants have been built in many parts of the world. They remove pollutants and contaminants from wastewater – but not completely. Difficult-to-remove substances include:
- metals
- pharmaceuticals
- personal care products
- cleaning agents
- microplastics
- As a result, discharged wastewater can still contain a mixture of pollutants, which may harm aquatic life.
Effects on Physiology
- The physiology of fish in treated wastewater is affected especially at warm temperatures (20°C).
- Minnows in warm water have a fivefold higher metabolic rate than in cold water (4°C).
- When exposed to treated wastewater, the rate increases even more: six to seven times higher than in cold water.
- Consequences:
- higher energy demand
- more stress on organs
- reduced volume of red blood cells → less oxygen available in the cells
- Together, these effects compromise the overall condition and health of the fish.
Effects on Behavior
- Fish behavior is influenced by wastewater under both warm and cold conditions:
Warm water:
- Minnows become less bold and stay longer in shelters.
- Problematic because higher metabolism requires more energy, which cannot be replenished as easily.
Cold water:
- Minnows spend less time in schools.
Consequences:
- harder to detect predators when alone
- lower survival chances
- reduced ability to find food collectively (especially critical in winter when food is scarce)
What You Can Do
- Dispose of (toxic) substances in appropriate containers instead of flushing them
- Dispose of medications correctly to reduce pharmaceutical pollution
- Use natural instead of chemical cleaning products
- Use as little as possible when applying personal care products such as sunscreen
