Measures needed to stem worsening sea pollution
Ongoing marine pollution poses a serious threat to the sea’s ecosystem. Sea pollution caused by micro-plastics is expanding. There are concerns about its harmful influence on fish, shellfish and other marine products.
Microplastics are extremely small pieces of plastic less than 5 millimetres in diameter. They are formed after such objects as plastic grocery bags, plastic bottles and expandable polystyrene deteriorate due to ultraviolet rays and salinity, and are broken into small pieces by waves and sand. Microbeads used in toothpaste and facial cleansers are also types of microplastics.
A high density of microplastics has been found in waters surrounding Japan – about 16 times greater than in the North Pacific Ocean as a whole and 27 times greater than in the seas around the world.
Microplastics can get into the bodies of small fish and seashells, so their influence is more likely to spread than that of large pieces of plastic waste.
According to research by the Tokyo University of Agriculture and Technology, microplastics have been detected in 80 per cent of the anchovies caught in Tokyo Bay. Another survey found the substance in a high percentage of fish caught in Osaka Bay and elsewhere.
There are concerns that pieces of microplastics taken inside a body may hinder the growth of living things as well as pollute their habit. It has also been pointed out that one of the properties of microplastics is that they can absorb polychlorinated biphenyls (PCBs) and other harmful material contained in seawater.
What effects could be caused if people consume fish in which harmful substances have accumulated? At the present, the matter remains unclear in many respects. Before the situation is exacerbated, it is essential to clarify the mechanisms through which such harmful substances can affect people.
It is difficult to recover the microplastics that extend thinly across the sea. The basis of necessary measures is to reduce the amount of plastic garbage that pours into the sea.
In its Basic Plan on Ocean Policy, the Japanese government cites a response to the spread of microplastics as one of its tasks. It will also work on compiling a strategy for recycling plastic resources, in a bid to reduce the large amount of plastic garbage.
The cosmetics industry has imposed voluntary restraints on the use of microbeads. The public and private sectors should join hands in promoting the reuse and recycling of plastic. It is also important to shore up monitoring and awareness activities, thereby preventing the illegal disposal of the substances.
From an international point of view, it is indispensable to promote environmental improvement in developing countries. Eight million tons of plastic waste has flowed into the sea annually worldwide. Much of the garbage is said to come from China and Indonesia. Some rivers there have been blanketed with garbage.
It is vital to improve the current situation in which garbage disposal systems cannot keep up with rapid population growth and economic development. Plastic, a type of synthetic resin, is resistant to decomposition in the natural world. Japan possesses advanced technology for such purposes as collecting and recycling plastic garbage. It is an important international contribution to assist developing countries in the growth of their recycling industries.