A study of Dee Why Lagoon has found high levels of plastic pollution.

The study of Dee Why Lagoon has been conducted by the Australian Microplastic Assessment Project (AUSMAP), with funding from the NSW Environment Protection Authority (EPA). AUSMAP is an established citizen science program that enables the community to collect microplastic data from waterways around the country and identify litter hotspots.

AUSMAP Research Director Dr Scott Wilson said Dee Why Lagoon was selected for the study after data collected by school children pointed to a potential issue with plastic pollution.

Scott Wilson

Scott Wilson

“We’d been doing samples around Sydney and around Australia. What came up is a school group led by some of the teachers at the Coastal Environment Centre at Narrabeen. They were doing some samples at different points and samples from Dee Why Lagoon came up as being extremely high microplastic loads in the lagoon itself.

“We did some subsequent sampling that confirmed it. It was strange as it’s a relatively small catchment. It had levels that were considered high. Anything over 250 microplastics per square metre (mp/sqm) is considered high, and we were getting 300-500 mp/sqm readings, depending along the shoreline in the lagoon.

“That raised some issues, as we know the lagoon is a protected wetland. It’s important for migratory birds and breeding habitat, and it’s one of the last natural wetlands in the Sydney region, so we decided to get to the bottom of it. That’s what led to the study and funding from the EPA to track back up the catchment to identify the sources,” said Dr Wilson.

The study sought to understand how microplastic was entering the lagoon by placing pollution traps on all the water inflows to the lagoon.

“What it showed us initially was that the source of the plastic was washing down and the microplastics were in similar proportions to what we were finding in the lagoon.

“Rather than big stuff being littered on the shore of the lagoon and breaking up, we were finding the microplastics already in the micro form washing through the stormwater system and the creek into the lagoon.

“It’s quite a unique finding. The original thought was a lot of the microplastic was ending up in our waterways by the break-up of big stuff breaking down. That still happens, but what we’re seeing here is pollution entering the waterway in microplastic form. It shows we need to manage the micro-debris,” said Dr Wilson.

The study has also found that one size does not fit all when it comes to the source of pollution entering waterways. Each inflow to the catchment was individually tracked, revealing different pollution signatures.

“What we found was different parts of the catchment that feed into the lagoon have different plastic pollution signatures, almost by land use type. Where you’ve got normal low density residential we got certain microplastics, the light industrial at Cromer had a different signature and the commercial and high density unit dwelling area had a different signature again.

“It’s telling us we cannot manage the catchment as one model. It will require a sub-catchment or neighbourhood approach to understand what the issue is,” said Dr Wilson.

Dr Wilson’s area of expertise is ecotoxicology, which seeks to understand the impact of chemicals on the environment. In recent years, he has focused on plastic pollution, particularly in marine environments.

“We are putting so many chemicals into the environment, we don’t know the impact they have singly or in combination. It’s an area of research that’s growing in importance.

“My real interest is trying to understand what impact we are having as humans and what pollutants we are putting into the environment. I’ve studied a range of pollutants over the years, including pesticides and metals. Plastic is one of the focus contaminants at the moment, and I’ve been working on it for the last ten years or so.

“What drives me is trying to get solutions in place that help us live better as a society and protect the environment,” said Dr Wilson.

The study of Dee Why Lagoon took place over eight months and was funded by the NSW EPA under a community litter grants program. Head of the EPA Litter Prevention Unit Rupert Saville said the project filled an important gap in knowledge around microplastic pollution.

Rupert Saville

Rupert Saville

“We’ve got a very sophisticated data framework in NSW where we’ve got terrestrial and marine based litter counts, but there was space for us to increase our knowledge of microplastics and develop a framework for assessing that going forward.

“We saw this as a great opportunity to partner with AUSMAP at a local level to trial the study method and see if this model could be expanded to a broader state-wide framework.

“It’s a beautiful thing to connect the community interest, concern and passion at a local level with the science, the Council and the State Government to then drive policy change.

“Having that AUSMAP process where we get the scientific validation is great. Citizen science projects in the litter space is really valuable, but having the scientific process in that is really powerful, so we have rigour around the data.

“Our whole program relies on partnership and collaboration with councils and communities. We have a whole range of citizen science based tools that rely on collaboration and building data capability,” said Mr Saville.

An architect of the ‘Don’t be a tosser!’ litter reduction campaign, Mr Saville said the data gathered would assist the EPA to drive pollution reduction outcomes.

“We are a very data driven program. We rely on the data telling us what’s ending up in the waterways. That informs our interventions, from source control to point of disposal, then to enforcement.

“The data drives where we target our advertising campaigns down to grant programs and the hotspots. Something like the Dee Why project, if we’re seeing microplastics coming from a particular location, we can target our program to that.

“We can inform particular businesses if we’re seeing their produce in the system. The data feeds up the line into what we call the litter journey, from source control to clean-up,” said Mr Saville.

Dr Wilson agreed, saying the ability to determine different pollution signatures from the different sources would allow for solutions to be targeted down to the street level.

“It becomes a more powerful education tool, that you can show data from a local street that has more impact. We drilled back further in the Cromer area, it has the industrial area, the high school and some synthetic sports fields.

“We installed litter baskets in the drains at different points around the Cromer area. We had 14 baskets and what we found is that in the industrial area there are different plastics to the residential area, it’s very specific.

“One of the issues we’re finding in some of those baskets are a key litter item, such as plastic pellets used for plastic moulding by manufacturers. They spill because they are so small and wash into the stormwater.

“There’s only a limited number of businesses that would be working in that, so we can go back and provide education and awareness on the management of those plastic pellets,” said Dr Wilson.

According to Mr Saville, the war on litter and plastic pollution can be won. A successful reduction in volume of litter of 40 percent from 2015 to 2020 is being followed up with a new target to reduce waste, including plastic.

“We’ve made a dent in the bigger stuff, so now we want to turn our attention to the smaller stuff that might travel into marine environments. We’ve got a new target that was just announced last month, to reduce litter in NSW by 60 percent from 2018/19 levels by 2030.

“We’ll target smaller items like cigarette butts, straws and plastic that may flow into marine environments. The short-term target is to reduce plastic litter items by 25 percent by 2025. All the data we have captured drives the policy to phase out things like straws,” said Mr Saville.

To find out how to get involved gathering data on microplastic pollution, visit the AUSMAP website.

Images: NSW EPA, AUSMAP