Pollution and Protection of the Baltic Sea

Today, fertilisers are widely used in agriculture. When it is very rainy during fertilisation, and there are no plants to hold the soil in place, the water washes fertilisers, herbicides, and pesticides out of the soil into water bodies. All substances that end up in flowing water eventually end up in the sea. Fertilisers are plant nutrients that cause algae and other aquatic plants to grow excessively when released into the water. When aquatic plants and algae die and decompose, oxygen is sucked from the water body, and aquatic animals die. Huge amounts of nutrients end up in water bodies from liquid manure spread as fertiliser on the fields, so enough oxygen is lost that animals cannot enter that water without dying.

There is very heavy shipping traffic in the Baltic Sea: on average, about two thousand ships sail there at a time. Many of them carry environmentally dangerous cargo, such as oil. Ship paints and care products also often contain environmentally hazardous substances. There are requirements for ships to preserve nature, but they are not always followed. However, the most dangerous are shipping accidents, because a large amount of oil or other harmful substances may escape into the sea. Oil is deadly to marine life, especially seabirds: even a drop of oil can damage the ability of birds' feathers to hold water.

Environmental toxins damage organisms during a long period, and their effects cannot be seen immediately. They often contain mercury or chlorine. Environmental toxins are generated during human activities (e.g. as a by-product of the production of other chemical substances, or incineration of hazardous waste). They end up in invertebrates, then fish. More environmental toxins accumulate in higher links in food chains, such as seals and eagles. If environmental toxins accumulate in animals, their lifespan will be shortened, and they may remain infertile.

More than forty years ago, the state of the Baltic Sea was even worse. The wastewater of many cities and settlements was not treated at all, fertilisers from the fields went directly into the water bodies, waste and wastewater from ships were also dumped directly into the sea. That is why the countries bordering the Baltic Sea have signed an international agreement called the Helsinki Convention. All these countries have promised to keep the Baltic Sea environment clean. After joining the Helsinki Convention, the Baltic Sea countries have built water treatment plants for all cities and larger settlements.