Up until the 1970s, there were few controls over water quality entering marine ecosystems.
The oceans were seen as huge and endless repositories for toxic waste with virtually no-cost dumping. Atmospheric testing of nuclear devices, and the dumping of toxic obsolete weapons and chemicals were undertaken with little thought as to the long-term consequences. The Great Lakes in North America were a turgid and relatively lifeless toxic wasteland, and the Thames river was an open sewer with very poor water quality and almost no life.
After decades of work to clean up these waterways and to reduce the emitting of pollutants into these ecosystems, salmon have returned to the Thames and the Great Lakes are slowly beginning to return to life. Australia has so many excellent waterways, rivers and marine environments including the Great Barrier Reef, that we should be and often are the standard bearers for improving water quality and maintaining ecosystems of world significance. Droughts throughout Australia have focussed attention on the quality and availability of clean drinking water, and the importance of conserving our water resources in a regularly parched country.
But have a look in your kitchen, store room or garage. How many materials do you own which are highly toxic to marine life - bleach, soaps, oils and detergents, with a large amount of plastic packaging and containers?
According to a 2015 study titled Plastic waste inputs from land into the ocean published in Science magazine, about 8 million tons of plastic enters the ocean every year. Part of this accumulates in five areas where currents converge, the gyres. The 2014 study Plastic Pollution in the World's Oceans estimates that at least 5.25 trillion pieces of plastic are currently in the oceans.
Carbon pollution has had the box seat in terms of media coverage and due to its effect on climate. There are many other forms of pollution which are damaging to the environment and to which construction activity is a major contributor.
As Australian population densities are concentrated in coastal areas and on waterways, we should improve the quality of water returning to our marine ecosystems.
Coral reefs in the Pacific and Indian Ocean are in trouble with coral being affected by human waste, plastics, oils and sewerage, nutrient runoff from agriculture. In many instances, coral cover on fragile reefs has diminished by more than 30 per cent since the 1970s when accurate surveys began. What does this do to the environment? We know that many fisheries are not producing the bounty they once had; with larger human populations, the intensity of fishing has increased. In tandem, the technology to locate and increase efficiency for commercial fishing operations has improved with GPS systems and ocean surface temperatures available to most advanced operators.
Plastic materials are used in buildings for packaging, in wiring, PVC ducts and skirtings, in coatings, and many paints. Considering that many of these plastics do not readily break down, many of those used during construction and after demolition may contribute to the load of rubbish in our waterways and oceans.
After a number of burrowing shearwaters died mysteriously, vivisection discovered that many had small pieces of plastic in their guts, which may have fooled them into believing they had enough stored food for their migration from the Southern ocean to the northern oceans. These birds skim the oceans hunting small fish and have been particularly vulnerable to plastic pollution.
Queensland universities have undertaken research into the use of bio-degradable plastics which can have a pre-determined lifespan. Plastic wrappings and protective coverings can be designed to disintegrate after exposure to water or UV sunlight. Plastic bags made from special sugars and starches may disintegrate after a predetermined period of exposure to water and sunlight.
The use of plastics has improved the availability of consumable products, drinks, fresh produce and products which are stored for longer periods. Car manufacturers now consider the obsolescence of components and formulate plastic to remain structurally sound for a specific time frame. Generally, no component is designed for a lifespan over 15 years, whereupon many vehicles will simply start to fall apart.
As construction and construction related activities generate large volumes of plastic waste, and contain plastics of various quality, is it time that designers and engineers more carefully consider the design life and disposal of these materials?
The collection, recycling and disposal of plastics has increased in Australia and advanced countries, with new products being reconstituted from plastic waste. UPVC floor boards and siding (cladding) are good examples.
Reducing plastic waste in our waterways should now be a consideration in packaging design for building products, and in terms of the biodegradable quality and design life of plastics.
A survey of the types of plastic materials in our waterways and oceans would reveal that construction activity is a major contributor, as is the unintended destruction of building stock during natural disasters, storms, floods, cyclones and tsunami events. Floods in Queensland pulverise and wash away buildings whereupon thousands of tonnes of debris end up contributing to the plastic and waste islands.
Inventors and scientists are developing debris catchers which could remotely collect floating debris and plastics and concentrate this for collection and recycling. The recycling could contribute to the cost of collection. An even more concerted effort is now required to reduce plastic and floating waste from entering our oceans in all countries and jurisdictions, and to collect and dispose of the huge volumes of waste now destroying ocean environments.
Most local authorities are designing hard waste pollution separators for their drains which flow into rivers or to sea. These trap and collect large volumes of plastics and other solids which would otherwise end up as floating pollution. These filtration systems have made a huge difference to intensely used marine environments such as Sydney Harbour.
Another major source of pollution in our waterways and marine environments is the use of lead sinkers by recreational fishers. Every year in Australia, many hundreds of tonnes of lead sinkers are sold and made. Most end up in sensitive marine ecosystems and may be a contributor to reef system degradation. Sinkers made from biodegradable plastics are now available which dissolve after continuous water exposure in a few weeks. The use of lead as sinkers and in all marine activity should be phased out in Australia to improve our marine environments.
Our oceans can no longer be considered the repository for large volumes of toxic waste, spent nuclear materials, unexploded munitions and plastic waste which does not readily break down.
A greater effort is required to identify what contribution construction activity has to the huge piles of plastics in our marine environments, and to make consumer and design changes which reduce pollution, trap and recycle these materials for safe disposal before they escape to damage our marine ecosystems.
A greater effort must be made to improve the quality of water entering our marine environments, to reduce the use of non-biodegradable packaging, and to collect toxic floating materials and dispose of these in the Oceans. With Australia an island surrounded by oceans and a huge coastlines facing the Indian Ocean, The Pacific Ocean the Coral Sea and Southern Ocean, we have a greater responsibility to ensure plastics and other pollutants do not irreversibly damage these environments.