The impact of litter in Melbourne’s waterways.
Litter is one of the most visible signs of pollution and the Yarra River in Melbourne, Victoria is getting trashed. At the end of 2016, over 1600 cubic metres of litter and debris was collected from the Yarra catchment. This amount of rubbish collected is increasing at an unmanageable rate. Data from Melbourne Water shows that the amount of litter and debris has more than doubled during 2015-16.
The Yarra River supplies most of Melbourne’s piped water. The river corridor is an important wildlife habitat for the region. It is a popular place for recreational and nature-based activities, which are vital to community well-being and the city’s prime livable status. The Werribee catchment (980 cubic metres), Dandenong (550 cubic metres) Westernport (400 cubic metres) and Maribyrnong (155 cubic metres) are all facing a similar rise in litter levels.
According to the Victorian Litter Strategy (2012-14), lifestyle changes has resulted in people spending more time in public places and consuming more items away from the home. We are busier, engage in more snacking and are increasing consumption of fast foods. Changing consumer patterns, such as purchasing food in take-away containers, has added to the likeliness of waste and litter occurring in public places. Inadvertent littering is a widespread issue. The CSIRO has found that easements, car parks, highways, industrial areas, retail strips and shopping areas have the highest levels of litter. In 2009-10, a total of 41,875 tonnes of litter was collected through litter bins in Victoria. This was a 46.8% increase from 2008-09 figures which correlates with exponential increase in litter throughout the waterways.
When properly disposed of, waste may be transported from public bins through waste services, scavengers or extreme weather. Garbage trucks can spill rubbish during collection. Birds and rodents may move rubbish out of open bins. Extreme rain and wind can carry lighter debris out of bins. These weather patterns transport litter and debris towards the gutter, along stormwater drains and into rivers or creeks.
Imperviousness of urban catchments increases run-off frequency and extreme weather exacerbates the amount of debris carried downstream. In December 2016, Melbourne experienced flash floods in which 54mm of rainfall was experienced in just 25 mins. As the water level rose, litter was carried downstream and distributed in treetops where it remained months after the floods had subsided.
Pick of the Litter.
Litter can be described as any small, medium or large item placed inappropriately. Many items can be reused or recycled and when these items become litter they are a lost resource. According to the Herald Sun, cigarette butts are the most common item picked up during litter clean-ups in Melbourne waterways. This is unsurprising. Approximately 7 billion cigarette butts are littered in Australia each year making it the most frequently identified litter item across the nation. Plastic litter objects contribute the largest amount of volume to the litter stream. My personal observations have validated this. To understand the kinds of litter that accumulates in Melbourne waterways, I picked up rubbish along the Merri Creek for one hour every week for five weeks. With the help of others, we collected 7.5 cubic metres of trash that would have otherwise traveled downstream.
The types of litter and debris in this sample amount has supported theories that public lifestyles away from home is a major factor on littering. Plastic food and beverage packaging made up approximately 70% of the waste collected. In a small 20m section of the Merri Creek, we found plastic bottles, straws, chocolate wrappers, coffee cups, chips packets, and plastic bags. Every week, more plastic packaging travelled downstream and collected in the same places we had already cleaned up.
The Yarra has had a 150 year history of neglect. Throughout the late 19th and early 20th centuries, heavy metals were deposited into the river from businesses such as the former Alphington paper mills or the Mobil dock at Coode Island. They settled to the bottom of the river bed, particularly in the lower reaches through the city and Port Melbourne. Progress has been made since those days. Industrial pollution no longer flows into the river, though the oils and grease remain today in several tributaries in the lower reaches such as Merri Creek and Moonee Ponds Creek.
Increasing amounts of litter in Melbourne’s waterways is putting severe stress on the Yarra and surrounds. Melbourne Water’s general manager of waterways and land, Tim Wood, has observed that this form of pollution has stifled plants, created traps for animals, affected water quality and decreased oxygen levels in the water. Discarded fishing line and other plastic waste has resulted in thousands of marine birds, mammals, reptiles and fish being killed or injured each year by polluting the water they live in, tanglement, strangling, choking and poisoning through consumption of litter. According to Environmental Justice Australia, run-offs from roads and other hard surfaces washed into the Yarra have been found to include heavy metals such as zinc, lead and copper, from car brakes and tyres.
Litter and waste is a significant threat to marine mammals in Port Phillip Bay where the Yarra flows into. This bay is one of several habitats to the rare Burrunan dolphin. The Burrunan dolphins are susceptible to numerous threats, including fisheries, tourism, anthropogenic contaminants, shipping, gas and oil mining exploration and environmental change. Under Victoria’s Flora and Fauna Guarantee Act, the Burrunan is listed as ‘Threatened’ with less than 150 dolphins in the Port Phillip Bay population. Survival and increase of this population would be a signal of health in the area.
Litter in Melbourne’s waterways impacts communities in ways that include reduced amenity, community pride and people’s feeling of safety. There is also a risk of contamination as inflows from stormwater drains may flush faecal matter, fertiliser run-off and pesticides into the river and sediment laced with bacteria are stirred up by increased water flows. The quality of the Yarra’s water and level of litter and debris fluctuates due to weather and water activities and can, at times, be too contaminated for swimming. Litter is a direct financial cost to local and state governments, and therefore to the community.
The story of pollution of the Yarra is a small piece in a much bigger picture. 95 per cent of the litter found on Australian beaches comes from suburban streets through the stormwater system. Plastic debris in the marine environment is widely documented, but the quantity of plastic entering the ocean from land waste is unknown. By linking worldwide data on solid waste, population density, and economic status, Science Magazine has estimated that eight million metric tons of plastic waste enter the oceans from land each year.
Fragmentation of larger pieces of plastic in the ocean results in tiny particles known as microplastics. Microplastics are also manufactured as micro beads for use in cosmetics, or micro fibres in clothing. On average, every mililitre of sediment contains 3.4 microplastics filaments. The worst incidence of this microplastic pollution has been found off the east coast of Bicheno, Tasmania where a concentration of 12 microplastics filaments were found per millilitre of sediment. These plastic particles are consumed by corals and zooplankton resulting in the introduction of plastic into the food chain. Microplastics can be passed up the food chain to fish, though the good news is that the microplastics appeared to have no effect on their behaviour and therefore, no significant toxicity has been recorded.
The Victorian Government is responsible for the statutory framework for litter prevention in Victoria. They have been actively working to strengthen litter reduction to protect unique natural assets such as the Yarra River and Port Phillip Bay. The Victorian Litter Strategy 2012–14 has been developed by Sustainability Victoria (SV) on behalf of the Victorian Government. The strategy provides programs to prevent litter, increase public place recycling and address illegal dumping in Victoria.
As part of this strategy, stormwater control measures have been integrated throughout the state of Victoria to reduce the amount of litter entering the stormwater system. Throughout Victoria, over 4000 litter traps have been installed. In 2009-10 they generated 2,700 tonnes of litter, a decrease of 2.7% from the previous year.
To decrease run-off frequency, imperviousness of select urban catchments has been reduced through the redesign of urban drainage systems. This utilises methods such as infiltration and rainwater harvesting. This allows small rain events to infiltrate, reuse or retain stormwater rather than piping it directly to streams, effectively reducing the frequency of the transportation of litter and debris. Examples of these alternative drainage systems can be found in Melbourne’s east where bioretention raingardens use soil, plants and microbes to biologically treat stormwater. The design is comprised of biofiltration basins, swales and dual purpose rainwater tanks. The results show that sufficient reductions in imperviousness and runoff frequency are possible to achieve improvements in stream health.
Education, knowledge sharing and community engagement plays a vital role in the health of Melbourne’s waterways. Organisations and Associations such as Yarra Riverkeeper Association and Friends of the Merri Creek offer monitoring, activities, tours, plantings, surveys, campaigns, presentations and working bees to increase public engagement at a grassroots level. These organisations played a vital role in the clean up of creeks and riverbeds after the December 2016 floods.
Approximately 95% of resources are allocated to litter management and 5% to litter prevention. Melbourne Water spends on average $3.3 million every year on litter removal from waterways. Parks Victoria has 17 litter traps on the Yarra River and another three on the Maribyrnong River. Any person who dumps industrial waste faces a fine of more than $7500 or up to $777,300 if prosecuted. Despite these efforts, the amount of litter being dumped in the Yarra is increasing.
Spanning from bulk buys, the ugly food movement, slow food and zero food waste, the sentiment of environmental responsibility remains a common thread in consumers and companies alike. Founded by Bea Johnson, the Zero Waste movement prevents all forms of waste generation at the consumer level. The principles of this movement are based on refusal of single-use items and plastics, reduction of resources consumed, reuse of resources such as packaging. If disposal is required all items must be perpetually recyclable, such as glass and aluminium; or compostable such as food scraps, wood and uncoated paper. Theoretically, this creates a circular economy for waste where nothing is ever sent to landfill.
Litter is a global concern. There are five trash gyres in the ocean. Discovered by Charles Moore in 1997, the biggest of these gyres is the Great Pacific Garbage Patch stretching across the Pacific Ocean just north of Hawaii. A global leader in this monumental waste collection task, The Ocean Clean Up is a non-profit organisation that is developing advanced technologies to rid the world’s oceans of plastic. Founded by Dutch inventor, Boyan Slat at 18 years of age, their equipment utilises the ocean currents to passively collect litter from the Great Pacific Garbage Patch through drifting systems. It is estimated that their technology will clean up half of the litter over a 5 year period.
There is hope yet.