parole chiave: inquinamento marino, emergenze ambientali
Are you aware that over 80% of marine pollution comes from land-based activities?
Environment pollution is a major concern in the world. It affects both land and the ocean. However, it is quite manageable to monitor plastic pollution on land than on water. But, it is important to understand that, eventually, most of the waste we produce on land reaches the oceans. Where does this pollution come from? Where does it go? One of the biggest sources is called nonpoint source pollution, which occurs as a result of runoff. or by a single source, like an oil or chemical spill. Often these events have large evident impacts, but fortunately, they occur less often. In order to provide you a quick list and let you you think about it, I will ist some of the worse causes.
Although Oil spills cause huge damage to the marine environment in fact are responsible for only 12% of the oil entering the seas each year. According to a study by the US National Research Council, 36% of oil impact comes from drains and rivers as waste from cities and industry. Some of this pollution are due to basic ignorance because people ignore what a wrong behaviour may cause.
In case of accident, the effects on the environment are immediately visible and quite hard to be tackled. Oil spills affect water spaces as well coastal environment and can last for years, killing marine and terrestrial species as birds, reptiles and mammals. A number of techniques are available but intervention time is still an important factor. Preventive measures and smart organisation are necessary to be able to intervene in a fast and adequate manner.
Very often we heard in the news about Fertilizers. They are material of natural or synthetic origin (chemicals) that is applied to soil or to plant tissues to supply one or more plant nutrients essential to the growth of plants.Fertilizer runoff from farms and lawns is becoming a huge problem for coastal areas.
Extra nutrients cause a flourishing of algal blooms, called eutrophication, that deplete the water’s dissolved oxygen and may suffocate other marine life. Regrettably, eutrophication has created enormous dead zones in several parts of the world, including the Gulf of Mexico and the Baltic Sea. Dead zones are hypoxic (low-oxygen) areas in the world’s oceans and large lakes, caused by “excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water … reference (NOAA)”.
Historically, many of these sites were naturally occurring. However, in the 1970s, oceanographers began noting increased instances and expanses of dead zones. These occur near inhabited coastlines, where aquatic life is most concentrated. Dead zones are bodies of water that do not have sufficient oxygen levels in order to support most marine life. Dead zones are caused by oxygen-depleting factors which include, but are not limited to, human pollution. When this is process occurs, oxygen levels decrease and elements such nitrogen and phosphorus increase. Let’s me make an example. A healthy river will have increased amounts of oxygen for consumption by organisms. As nitrogen increases, algae produce large amounts of oxygen, but die because of increased nitrogen. Decomposers then use all of the remaining oxygen decomposing the algae. This deadly cycle results in an vicious equation: “no oxygen left and no oxygen being produced“. This is caused by eutrophication.
In March 2004, when the UN Environment Programme (UNEP) published its first Global Environment Outlook Year Book, it reported 146 dead zones in the world’s oceans where marine life could not be supported due to depleted oxygen levels. Some of these covered 70,000 square kilometres (27,000 mi²). This number is growing reducing oxygen production in the oceansm one the most important factor for our survivability. A 2008 study counted 405 dead zones worldwide. In other words, deadzones are deeply affecting ocean cycle and reduce carbon dioxide filtering by Ocean. That generates more CO2 in the atmosphere and temperature increase.
Dumping areas so called plastic islands
Everything we produce will make its way to the ocean. Plastic bags, glass bottles, cigarette butts, packaging material – if not correctly disposed, soon or later, almost everything we abandone can reach the sea. Plastic garbage, which decomposes very slowly (even centuries), is often mistaken for food by marine animals. High concentrations of plastic material, particularly plastic bags, have been found blocking the breathing passages and stomachs of many marine species, including whales, dolphins, seals and marine turtles. Abandoned fishing lines and nets as well plastic six-pack drinks rings can also choke marine animals. This garbage can also come back to shore, where it pollutes beaches and other coastal habitats. Since 2008 have been spotted large mass of debris, collected by ocean currents. They are huge and pose a clear danger for many living species as well Humans.
In many parts of the world, sewage flows untreated, or under-treated, into the ocean. For example, 80% of urban sewage discharged into the Mediterranean Sea is untreated. This sewage can also lead to eutrophication. In addition, it can cause human disease and lead to important beach closures. It is not only an health or environmentale issue but economic. Human work activities are deeply affected. Maritime routes instability may grow and favorite criminal activities in sensitive areas. The most known is piracy, boosted by local fishing condition degradation.
All of us has received a quantity of toxic contaminants. Chemicals are everywhere and what they may cause is still a big question mark. Almost every marine organism, from the tiniest plankton to whales and polar bears, has been contaminated by pesticides and chemicals used in common consumer products. Some of these chemicals enter the sea through deliberate dumping because of lack of control and criminal actions. For centuries, the oceans have been a convenient dumping ground for waste generated on land. Officially this continued until the 1970s, with dumping at sea as accepted practise for disposal of nearly everything. However, although this is illegal organised crime organisations include illegal disposal of toxic material and radioactive waste at sea. Dumping of the most toxic materials was banned by the London Dumping Convention in 1972, and an amended treaty in 1996 (the London Convention) further restricted what could be dumped at sea. However, there are still problems of already-dumped toxic material, and even the disposal of permitted substances at sea can be a substantial environmental hazard. A recent one is the release of radioactive waters from Fukushima plants into the ocean.
Chemicals also enter the sea from land-based activities by rivers flowing or by air. They escape into water and air during their manufacture, penetrate in the soil reaching groundwaters. Once in the environment, they travel for long distances by winds and ocean currents. Although ocean is potentially a large diluent, in reality chemicals have not disappeared, some toxic man-made chemicals have even become more concentrated and have been found in the food chain. Think about level of so called heavy metals in large fish.
So, what are the effects over our species?
Biologists believe that animals at the bottom of the food chain, such as plankton and crustacenas as krill absorb the chemicals as they feed. Chemicals accumulate in these organisms, becoming much more concentrated in their bodies than in the surrounding water or soil. These organisms are eaten by small animals, and the concentration rises again. These animals are in turn eaten by larger animals, which can travel large distances dispersing their increased chemical load. Big Tuna, sharks and swordfish reach high level of contaminants because they live more then other fish.
Regrettably we may become contaminated by eating seafood. For instance, Shark meat is very toxic. Besides, polimeric components are release in food and drinks. Even by tap drinking waters because nanoplastics are performing as carriers of chemicals and toxic substances due to their porosity. Although there are not clear evidences about human risks, many scientists are convinced that a number of man-made chemicals can cause serious health problems – including cancer, damage to the immune system, behavioural problems, and reduced fertility.
Now … you Know and can act to mitigate this impact. Think about it. The future is yours.
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