Water Pollution In Australia: Common Contaminants Revealed

Water pollution is a pressing issue in Australia, with a range of contaminants affecting its water bodies. From plastics and pesticides to sewage and industrial waste, the sources of pollution are diverse and have detrimental effects on the environment and human health. The Great Barrier Reef, for instance, faces water pollution that harms its rich biodiversity. With Australia being the driest inhabited continent, addressing water pollution is crucial for the country's sustainable development. This introduction will delve into the various forms of water pollution in Australia, exploring their causes, impacts, and potential solutions, highlighting the urgency of tackling this environmental challenge.

Plastics, pesticides, herbicides, metals, and terrigenous sediments

Plastics

Plastic pollution is a significant issue in Australia, with the country's waters contaminated by tiny plastic fragments, known as microplastics. These microplastics, mostly less than 5mm in size, are found in high concentrations in Australian seas, with around 4,000 pieces per square kilometre of seawater. They are transported to the oceans through rivers, wind, tides, rainwater, storm drains, sewage disposal, and even directly from boats and offshore installations. The production of plastic has increased dramatically, from 1,700,000 tonnes in 1950 to 280,000,000 tonnes in 2011, with Australia using 1,476,690 tonnes in 2011-2012, of which only 20.5% was recycled. Most of these plastics were used for single-use disposable packaging, contributing to coastal biodiversity loss and the ruin of recreational sites. Plastics become even more toxic when they enter the oceans, as they adsorb oily pollutants on their surface, which can then be ingested by marine animals and transferred up the food chain, affecting entire food webs, including humans.

Pesticides and Herbicides

Pesticides and herbicides are commonly used in agriculture to increase production and ensure food affordability for the growing population. However, their use has led to water contamination, with high concentrations detected in water bodies worldwide. While biodegradable and biocompatible pesticides have been introduced to mitigate the issue, the excessive use of pesticides and herbicides in agriculture continues to be a global concern, particularly in developing countries. The generated wastewater, contaminated with pesticides, negatively impacts human health, ecosystems, and the aquatic environment.

Metals

Heavy metals, such as mercury, are another common pollutant in Australian waters. These metals can originate from acid sulfate soils and manufacturing industries, disturbing the dissolved oxygen levels and pH of water bodies. Additionally, natural disasters like flooding can cause the runoff of heavy metals into waterways.

Terrigenous Sediments

Terrigenous sediments, along with debris, contribute to water pollution in Australia, particularly in coastal rivers and estuaries. These sediments can have a direct impact on the aquatic ecosystem, leading to the ingestion of toxic materials by shorebirds, turtles, and other marine organisms.

Eutrophication and siltation

Siltation, or sedimentation, is another issue affecting Australian waterways. It occurs when fine particles of soil, silt, or sand are deposited in bodies of water, often due to erosion or human activities such as construction or agriculture. Siltation can have several negative impacts on aquatic ecosystems. Firstly, it can reduce water quality by decreasing light penetration and oxygen levels, affecting the growth and survival of aquatic plants and organisms. Secondly, siltation can alter the physical characteristics of water bodies, such as depth and flow rates, which can impact the habitat and behaviour of aquatic organisms. Additionally, siltation can smother aquatic plants and organisms, hindering their growth and survival.

Both eutrophication and siltation have significant ecological consequences. Eutrophication can lead to the deterioration of aquatic ecosystems, including freshwater lakes and coastal marine environments, threatening commercial and recreational fisheries. Siltation can result in the loss of river connectivity, affecting the movement of organisms and the natural flow of waterways. Additionally, the increased sediment load in water can impact water treatment processes, as sediment particles can interfere with filtration systems and require additional treatment measures.

To combat eutrophication, catchment managers in Australia need to assess catchment nutrient loads and implement long-term planning based on annual average nutrient load data. This information can help identify critical source areas contributing most of the nutrients to a catchment, allowing for targeted mitigation strategies. Regarding siltation, effective land management practices, such as reforestation and erosion control measures, can help reduce sediment runoff into water bodies. Additionally, regular maintenance and proper design of stormwater drainage systems can minimise the amount of silt and sediment entering aquatic ecosystems.

By addressing eutrophication and siltation through appropriate management strategies, Australia can work towards improving water quality and preserving the biodiversity and ecological integrity of its aquatic ecosystems. These efforts are crucial for ensuring the long-term health and sustainability of Australia's unique and valuable water resources.

Sewage treatment plants

The Elanora Wastewater Treatment Plant in Queensland, the Bondi Waste Water Treatment Plant in New South Wales, and the Liverpool Water Recycling Plant in New South Wales are a few examples of sewage treatment plants in Australia. The Western Treatment Plant in Melbourne is the largest in terms of area occupied.

However, sewage treatment plants face significant challenges due to the materials that people dispose of down their drains and toilets. Many treatment plants are not equipped to handle certain wastes, such as feminine hygiene products, which can cause blockages and pass through the system untreated. Additionally, industries, offices, and schools contribute a range of chemicals and materials that can be challenging for plants to treat effectively.

The release of untreated sewage can occur due to breakdowns or blockages in pumping stations, sewer pipes, or the plants themselves. While modern treatment plants have backup systems to prevent major water pollution incidents, the impact of untreated sewage on the environment and aquatic life can be detrimental.

To address these issues, authorities have implemented strict guidelines for industries disposing of materials or chemicals into the sewerage system. The Environmental Protection Act 1994 also regulates the disposal of certain contaminants, requiring a license for specific discharges.

Industrial waste

Industries such as oil refineries, paper and pulp mills, automobile, chemical, and electronic manufacturers release wastewater into major water bodies, polluting rivers and oceans. The toxins from these industries can have detrimental effects on the environment and human health. For example, the discharge from power plants and industrial sites into river systems can increase water temperatures, impacting aquatic species' spawning, breeding, and migration patterns.

Additionally, industrial air pollutants near regional populations are increasing, particularly in coastal regions. These pollutants contribute to nutrient-rich runoff, which can lead to excessive algae growth and, in extreme cases, deoxygenation of the water.

Furthermore, industrial waste containing chemicals such as herbicides, pesticides, and fertilizers can enter water bodies through natural runoffs. Stormwater drains collect runoff wastes from industries and agricultural areas, which then merge into larger water bodies.

The Australian government has implemented measures to address industrial water pollution, such as the PFAS National Environmental Management Plan, which regulates PFAS-contaminated sites. However, the impact of industrialization on water pollution remains a significant challenge, and proper treatment of industrial wastewater is crucial to mitigate its adverse effects.

Bushfires and water quality

Water pollution is a common environmental issue in Australia, with plastics, pesticides, herbicides, metals, terrigenous sediments, debris, and sewage all contributing to the problem. Bushfires also play a significant role in degrading water quality and altering stream ecosystems.

The impact of bushfires on water quality is complex and depends on various factors such as the amount and intensity of rainfall, the type of forest burned, and the characteristics of the catchment area. Bushfires can reduce water quality immediately and for many years afterward. Ash, soil, sediment, and other burnt materials can enter waterways, changing the water chemistry and reducing oxygen levels, which can be harmful to aquatic life. This is known as a blackwater event, which can contribute to fish deaths and increase the risk of algal blooms.

In the mid-western region of New South Wales (NSW), Australia, the 2019-2020 bushfires significantly impacted water quality. Water samples collected from affected catchments, intakes, purification units, and reservoirs exhibited high turbidity, elevated levels of suspended sediments, pH, and alkalinity, posing significant threats to aquatic ecosystems and water purification processes.

To protect water catchments after a bushfire, immediate actions should be taken, including establishing water quality monitoring programs and implementing soil erosion mitigation measures such as pushing back topsoil with heavy machinery, erecting silt fences, and planting shrubs and trees to stabilize the soil structure. The National Water Quality Management Strategy (NWQMS) provides a framework for setting water quality objectives and implementing preventative and rehabilitation actions tailored to specific environments.

While bushfires can have detrimental effects on water quality, aquatic ecosystems are remarkably resilient and often recover quickly if there is connectivity between affected and unaffected habitats. Additionally, the Australian government provides coordination, policy advice, and funding assistance during and after bushfires to support rehabilitation efforts.

Frequently asked questions