Water Pollution In Australia: A Comprehensive Overview

Water pollution is a pressing issue in Australia, with a range of contaminants affecting its water bodies. From plastics and herbicides to sewage and toxins from oil refineries, the sources of pollution are diverse and have a detrimental impact on the environment and human health. The Great Barrier Reef, a biodiverse natural wonder, is facing the adverse effects of water pollution, and local communities are also suffering. With Australia being the driest inhabited continent, addressing water pollution is crucial for the country's sustainable development and the preservation of its unique ecosystems. This introduction will explore the extent and consequences of water pollution in Australia, highlighting the urgent need for effective solutions.

Plastic pollution

The sources of marine plastics in Australian waters are both domestic and international, including populated areas along the east coast and maritime operations. Plastics are mostly made from oil and gas, and their increased affordability has reduced incentives to reuse or recycle everyday items. At the same time, plastic production has skyrocketed, with a massive increase from 1,700,000 tonnes in 1950 to 280,000,000 tonnes in 2011. In Australia, during 2011-2012, 1,476,690 tonnes of plastic were used, of which only 20.5% was recycled. The majority of this plastic was used for manufacturing single-use disposable packaging, including plastic bottles, cups, and bags.

The Australian Marine Conservation Society has been working to tackle this issue by spreading awareness and providing resources to fight plastic pollution in communities. They have also exposed the efforts of supermarkets in reducing plastic packaging, pushing for more significant action. Additionally, organisations like WWF Australia have been promoting solutions, such as supporting businesses that offer reusable and compostable alternatives to single-use plastics.

While there is still much to be done, Australia has the opportunity to halve the amount of plastic pollution entering its natural environments. Banning single-use plastics and implementing measures to improve recycling and encourage better alternatives are crucial steps towards protecting the country's unique wildlife and natural sites, like the Great Barrier Reef, which is already facing the adverse effects of water pollution.

Sewage treatment plants

Water pollution is a significant environmental issue in Australia, with plastic pollution being the primary type. Each square kilometre of Australian seawater is contaminated by approximately 4,000 pieces of tiny plastics, which are loaded with toxins that can negatively impact marine life and, consequently, human health. Other contaminants in Australian water bodies include pesticides, herbicides, metals, terrigenous sediments, and debris.

One example of a sewage treatment plant in Australia is the Elanora Wastewater Treatment Plant in Queensland. This plant has a rating of 4.3 out of 5 stars. Another example is the Bondi Waste Water Treatment Plant in New South Wales, which has a rating of 3.6 out of 5 stars.

While sewage treatment plants help mitigate water pollution, they also contribute to it. Toxins from oil refineries, paper and pulp mills, automobile manufacturers, chemical manufacturers, and electronic manufacturers can end up in the water bodies that receive treated wastewater. Additionally, runoff wastes from industries and agricultural areas can enter storm water drains and eventually make their way into larger water bodies, further polluting them.

To address this issue, the Environmental Protection Act 1994 requires authorities to obtain a license for disposing of certain types of waste. However, more comprehensive measures are needed to reduce water pollution in Australia and protect its natural sites, such as the Great Barrier Reef, and the health of its marine ecosystems and dependent communities.

Industrial waste

Australia, the driest inhabited continent, faces significant water pollution from industrial waste. Industries account for about 20% of freshwater withdrawal worldwide, and while in some cases, this water is properly cleaned and disposed of in an environmentally friendly manner, in other cases, it is discharged untreated into public waters.

In Australia, wastewater from industries is treated and licensed under the Environmental Protection Act 1994 and the Environmental Protection (Water and Wetland Biodiversity) Policy 2019. However, as the country faces ongoing drought and increasing water demand, the threat of water shortages and pollution looms large.

The primary types of water pollutants from industrial waste include pathogenic and non-pathogenic microorganisms, heavy metals, hazardous wastes, sediments, and per- and polyfluorinated alkyl compounds (PFAS). Heavy metals, such as copper, lead, and selenium, come from manufacturing, mining, and exhaust air systems. Hazardous wastes, which are highly flammable and corrosive, originate from construction, demolition, manufacturing, trade, and waste treatment processes. Sediments are caused by the discharge of polluted industrial wastewater, leading to the accumulation of non-degradable toxins in aquatic sediments, which can enter groundwater through cracks in the ground or during floods or dredging. PFAS are prevalent in the textile industry, hard chrome plating, and extinguishing agents.

The consequences of industrial wastewater pollution are severe, leading to the illness and death of fish, crustaceans, and other aquatic creatures, thereby reducing biodiversity. Additionally, contaminated water can enter drinking water supplies, posing health risks to human populations.

Bushfires

Bushfire ash contains organic carbon, nitrogen, and phosphorus, which can lead to blue-green algae outbreaks. When ash enters the water supply, it can deplete oxygen levels and alter water chemistry, potentially causing fish kills and toxic chemicals. The more sediment in the water, the harder it is to treat. Steep, dry-forested areas are particularly prone to mudslides after bushfires, which can further impact water quality.

During the 2019-2020 bushfire season, Sydney's water supply was at risk of pollution by bushfire ash in the Warragamba Dam catchment, which supplies 80% of the city's drinking water. Some regional communities in New South Wales, such as Tenterfield, had their drinking water supply polluted by ash, forcing residents to boil their water. The turbidity level in the water, which indicates the concentration of suspended solids, took about four weeks to reduce from 195 to 12 NTU.

The impact of bushfires extends beyond water pollution, with infrastructure damage, loss of life, property destruction, and negative health consequences. The 2019-2020 bushfires in Australia were unprecedented in scale and intensity, with global reports stating that up to 67%-83% of significant rainforests and eucalypt forests were severely burnt. The fires emitted 400 megatonnes of carbon dioxide into the atmosphere, contributing to climate change and increasing the frequency and intensity of future bushfires.

Salinity

Primary salinity refers to the large salt deposits that are a natural feature of the Australian landscape, stored in deep soils, as surface salt deposits, or in salt lakes. It occurs when rainfall interacts with geographical features over long periods. Rainfall absorbs salt from the surface and carries it into the subsoil, where it is stored until it is mobilised by groundwater and rising water tables. As the water evaporates, it leaves behind concentrated salt, resulting in soil salinity.

Secondary salinity refers to additional salt transported to the soil surface or waterways due to altered land use, including vegetation clearance, poor land management, irrigation, and industrial practices. Land clearing has resulted in the loss of native vegetation, replaced by shallow-rooted annual plants that cannot adequately absorb stored and rising groundwater. This creates an imbalance in the hydrological cycle, resulting in dryland salinity.

Climate change may have mixed effects on salinity in Australia. While a reduction in annual rainfall could lead to decreased salinity, the impact on salt concentration in water bodies is expected to be detrimental. Lower rainfall rates may reduce the frequency of the water table being recharged, decreasing the likelihood of it transporting underground salts to the land's surface. However, the reduction of water in streams, rivers, and other water bodies may result in an increase in salt concentration.

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