The ocean is swimming in plastic and it’s getting worse – we need connected global policies now



Fotos593 / shutterstock

Steve Fletcher, University of Portsmouth and Keiron Philip Roberts, University of Portsmouth

It seems you cannot go a day without reading about the impact of plastic in our oceans, and for good reason. The equivalent of a garbage truck of plastic waste enters the sea every minute, and this increases every day. If we do nothing, by 2040 the amount of plastic entering the ocean will triple from 13 million tonnes this year, to 29 million tonnes in 2040. That is 50kg of waste plastic entering the ocean for every metre of coastline.

Add to that almost all the plastic that has entered the ocean is still there since it takes centuries to break down. It is either buried or broken down into smaller pieces and potentially passes up the food chain creating further problems.

Despite this, plastic has also been a saviour. During the COVID-19 pandemic plastic used in face masks, testing kits, screens and to protecting food has enabled countries to come out of lockdown during and support social distancing. We still need to use these items until sustainable and “COVID safe” alternatives are available. But we also need to look to the future to reduce our dependence on plastic and its impact on the environment. With plastic in the ocean being a global problem, we need global agreements and policies to reverse the plastic tide.




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Ambitious policies are needed

Environment ministers of the G20 group of the world’s most economically powerful countries and regions met on September 16 to discuss their immediate challenges, with marine plastic pollution a top priority. A key item for discussion was “safeguarding the planet by fostering collective efforts to protect our global commons”. This means working out how we can continue to use the planet’s resources sustainably without harming the environment.

A global analysis of plastics policies over the past two decades found that typical reactions to marine plastic litter were bans or taxes on individual or groups of plastic items within single countries. So far, 43 countries have introduced a ban, tax or levy on plastic bags. Other plastic packaging or single-use plastic products were banned in at least 25 countries, representing a population of almost 2 billion people in 2018.

But plastic waste doesn’t respect land or ocean borders, with mismanaged plastic waste easily migrating from country to country when leaked into the environment. Policies also need to consider the entire plastics life cycle to stand a chance of being effective. For example, the inclusion of easier to recycle plastics in consumer products sounds positive, but their actual recycling rate depends on effective sorting and collection of plastic waste, and appropriate infrastructure being in place.




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Ultimately, a joined up but adaptable set of rules and guidelines are needed so all plastic producers and users can prevent its leakage across all stages of the plastics life cycle.

The G20 has sought to lead action on marine plastic litter through a 2017 Action Plan on Marine Litter which set out areas of concern and possible policy interventions, and through connections to initiatives such as the UN Environment Programme’s Global Partnership on Marine Litter and most recently the Osaka Blue Ocean Vision. The Osaka vision was agreed under the Japanese G20 presidency in 2019 and commits countries to “reduce additional pollution by marine plastic litter to zero by 2050”. Although an agreement led by the G20, it now has the support of 86 countries.

But even with these agreements in place, plastic entering the ocean will still only reduce by 7% by 2040. We need ambitious new agreements as current and emerging policies do not meet the scale of the challenge.

A consensus is forming that the G20 and other global leaders must focus on a systemic change of the plastics economy. This includes focusing on “designing out” plastics, promoting technical and business innovation, immediately scaling up actions known to reduce marine plastic litter, and transitioning to a circular economy in which materials are fully recovered and reused. These actions have the potential to contribute to the G20’s vision of net-zero plastics entering the ocean by 2050, but only if ambitious actions are taken now.The Conversation

Steve Fletcher, Professor of Ocean Policy and Economy, University of Portsmouth and Keiron Philip Roberts, Research Fellow in Clean Carbon Technologies and Resource Management, University of Portsmouth

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How bushfires and rain turned our waterways into ‘cake mix’, and what we can do about it



The Murray River at Gadds Reserve in north east Victoria after Black Summer bushfires.
Paul McInerney, Author provided

Paul McInerney, CSIRO; Anu Kumar, CSIRO; Gavin Rees, CSIRO; Klaus Joehnk, CSIRO, and Tapas Kumar Biswas, CSIRO

As the world watched the Black Summer bushfires in horror, we warned that when it did finally rain, our aquatic ecosystems would be devastated.

Following bushfires, rainfall can wash huge volumes of ash and debris from burnt vegetation and exposed soil into rivers. Fires can also lead to soil “hydrophobia”, where soil refuses to absorb water, which can generate more runoff at higher intensity. Ash and contaminants from the fire, including toxic metals, carbon and fire retardants, can also threaten biodiversity in streams.




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As expected, when heavy rains eventually extinguished many fires, it turned high quality water in our rivers to sludge with the consistency of cake mix.

In the weeks following the first rains, we sampled from these rivers. This is what we saw.

Sampling the upper Murray River

Of particular concern was the upper Murray River on the border between Victoria and NSW, which is critical for water supply. There, the bushfires were particularly intense.

Sludge in Horse Creek near Jingellic following storm activity after the fire.
Paul McInerney/Author Provided

When long-awaited rain eventually came to the upper Murray River catchment, it was in the form of large localised storms. Tonnes of ash, sediment and debris were washed into creeks and the Murray River. Steep terrain within burnt regions of the upper Murray catchment generated a large volume of fast flowing runoff that carried with it sediment and pollutants.

We collected water samples in the upper Murray River in January and February 2020 to assess impacts to riverine plants and animals.

Our water samples were up to 30 times more turbid (cloudy) than normal, with total suspended solids as high as 765 milligrams per litre. Heavy metals such as zinc, arsenic, chromium, nickel, copper and lead were recorded in concentrations well above guideline values for healthy waterways.

Ash and sediment blanketing cobbles in the Murray River.
Paul McInerney/Author Provided

We took the water collected from the Murray River to the laboratory, where we conducted a number of toxicological experiments on duckweed (a floating water plant), water fleas (small aquatic invertebrates) and juvenile freshwater snails.

What we found

During a seven-day exposure to the bushfire affected river water, the growth rate of duckweed was reduced by 30-60%.

The water fleas ingested large amounts of suspended sediments when they were exposed to the affected water for 48 hours. Following the exposure, water flea reproduction was significantly impaired.

And freshwater snail egg sacs were smothered. The ash resulted in complete deaths of snail larvae after 14 days.




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These sad impacts to growth, reproduction and death rates were primarily a result of the combined effects of the ash and contaminants, according to our preliminary investigations.

But they can have longer-term knock-on effects to larger animals like birds and fish that rely on biota like snail eggs, water fleas and duckweed for food.

What happened to the fish?

Immediately following the first pulse of sediment, dead fish (mostly introduced European carp and native Murray Cod) were observed on the bank of River Murray at Burrowye Reserve, Victoria. But what, exactly, was their cause of death?

A dead Murray Cod found on the banks of the Murray River following storms after the bushfires.
Paul McInerney/Author Provided

Our first assumption was that they died from a lack of oxygen in the water. This is because ash and nutrients combined with high summer water temperatures can trigger increased activity of microbes, such as bacteria.

This, in turn can deplete the dissolved oxygen concentration in the water (also known as hypoxia) as the microbes consume oxygen. And wide-spread hypoxia can lead to large scale fish kills.




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But to our surprise, although dissolved oxygen in the Murray River was lower than usual, we did not record it at levels low enough for hypoxia. Instead, we saw the dead fish had large quantities of sediment trapped in their gills. The fish deaths were also quite localised.

In this case, we think fish death was simply caused by the extremely high sediment and ash load in the river that physically clogged their gills, not a lack of dissolved oxygen in the water.

These findings are not unusual, and following the 2003 bushfires in Victoria fish kills were attributed to a combination of low dissolved oxygen and high turbidity.

So how can we prepare for future bushfires?

Preventing sediment being washed into rivers following fires is difficult. Installing sediment barriers and other erosion control measures can protect specific areas. However, at the catchment scale, a more holistic approach is required.




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One way is to increase efforts to re-vegetate stream banks (called riparian zones) to help buffer the runoff. A step further is to consider re-vegetating these zones with native plants that don’t burn easily, such as Blackwood (Acacia melanoxylin).

Streams known to host rare or endangered aquatic species should form the focus of any fire preparation activities. Some species exist only in highly localised areas, such as the endangered native barred galaxias (Galaxias fuscus) in central Victoria. This means an extreme fire event there can lead to the extinction of the whole species.

Ash and dead fish on the banks of the Murray River near Jingellic following Black Summer fires.
Paul McInerney/Author Provided

That’s why reintroducing endangered species to their former ranges in multiple catchments to broaden their distribution is important.

Increasing the connectivity within our streams would also allow animals like fish to evade poor water quality — dams and weirs can prevent this. The removal of such barriers, or installing “fish-ways” may be important to protecting fish populations from bushfire impacts.

However, dams can also be used to benefit animal and plant life (biota). When sediment is washed into large rivers, as we saw in the Murray River after the Black Summer fires, the release of good quality water from dams can be used to dilute poor quality water washed in from fire affected tributaries.




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Citizen scientists can help, too. It can be difficult for researchers to monitor aquatic ecosystems during and immediately following bushfires and unmanned monitoring stations are often damaged or destroyed.

CSIRO is working closely with state authorities and the public to improve citizen science apps such as EyeOnWater to collect water quality data. With more eyes in more areas, these data can improve our understanding of aquatic ecosystem responses to fire and to inform strategic planning for future fires.

These are some simple first steps that can be taken now.

Recent investment in bushfire research has largely centred on how the previous fires have influenced species’ distribution and health. But if we want to avoid wildlife catastrophes, we must also look forward to the mitigation of future bushfire impacts.The Conversation

Paul McInerney, Research scientist, CSIRO; Anu Kumar, Principal Research Scientist, CSIRO; Gavin Rees, Principal Research Scientist, CSIRO; Klaus Joehnk, Principal research scientist, CSIRO, and Tapas Kumar Biswas, Senior scientist, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How Earth’s plastic pollution problem could look by 2040



Rich Carey/Shutterstock

Costas Velis, University of Leeds and Ed Cook, University of Leeds

During a visit to a bookstore a few weeks ago, we couldn’t help but stare at a display unit featuring no fewer than ten books telling you how to rid plastics from your daily life. We’re bombarded by information on the topic of marine litter and plastic pollution, but how much do we really know about the problem?

Think about other planetary challenges, like climate change or ozone layer depletion. Mature areas of research have developed around them, allowing scientists to identify where the gases that cause these problems come from, and how much reaches the atmosphere each year.

But when it comes to plastic pollution, we know close to nothing about how and where plastic waste is generated, managed, treated and disposed of, especially in low and middle income countries. As a result, we’re struggling to limit the amount of litter accumulating in the environment.

Our research published in Science involved a herculean effort to spot, track and model the current and future flows of plastics into the world’s land and waterbodies. We found that plastic entering the marine environment is set to double by 2040 and, unless the world acts, more than 1.3 billion tonnes of plastic waste will be dumped on land and in waterbodies.

By identifying the ways in which this litter is produced and distributed, we’ve also discovered how best to reduce the plastic deluge. In the process, we found the unsung heroes on the frontline fighting the pollution crisis who could be the world’s best hope of stemming the tide.

Discarded face masks on a rocky beach.
Single-use plastic consumption has increased during the pandemic.
Fevziie/Shutterstock

The world’s plastic problem in numbers

We developed a model called Plastic-to-Ocean (P₂O) which combines years of accumulated knowledge on global flows of plastic. It compares our current production, use and management of waste with what is projected in the future.

Do you burn your waste in the garden or in the street? Do you drop it into the river? If you answered no to both of these questions then you are possibly one of the 5.5 billion people whose waste gets collected. If you were among the remaining two billion, what would you do with your uncollected waste? Would you make use of a nearby stream, cliff edge, or perhaps squirrel the odd bag in the woods after dusk?

More often than not, uncollected plastic waste is simply set on fire as a cost-free and effective method of disposal. Our model suggests that cumulatively, more than 2.2 billion tonnes of plastic will be open burned by 2040, far more than the 850 million tonnes that’s anticipated to be dumped on land and the 480 million tonnes in rivers and seas.

Having tracked the sources of plastic items through the supply chain and their fate in the environment, we explored what might help reduce aquatic pollution. We found that the single most effective intervention is to provide a service for the two billion people who currently don’t have their waste collected.

A graph showing how different measures could reduce the flow of plastic into the ocean.

Breaking the Plastic Wave, Author provided

But, of the nine interventions we tested, none solved the problem on their own. Only an integrated approach that in addition to increasing collection coverage includes interventions such as reducing demand for single-use and unrecyclable plastic and improving the business case for mechanical recycling, could be successful. For the countries suffering most from plastic pollution, this knowledge could offer a way forward.

But even in our best-case scenario, in which the world takes the kind of concerted and immediate action proposed in our study, approximately 710 million tonnes of plastic waste will be released into the environment by 2040. That may sound a lot, but it would mean an 80% reduction in the levels of plastic pollution compared to what will happen with no action over the next two decades.




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Could waste pickers save the day?

Our work also cast light on the contributions of 11 million waste pickers in low and middle-income countries. These informal workers collect waste items, including plastics, for recycling, to secure a livelihood for day-to-day survival. The model estimates that they may be responsible for 58% of all plastic waste collected for recycling worldwide – more than the combined formal collection services achieve throughout all the high-income countries put together.

Without this informal waste collection sector, the mass of plastic entering rivers and the ocean would be considerably greater. Their efforts should be integrated into municipal waste management plans, not only to recognise their tremendous contribution but to improve the appalling safety standards that they currently endure.

A man in India peddles a bicycle cart to collect rubbish.
An additional 500,000 people will need to be reached by waste collection services each day until 2040.
EPA-EFE/JAIPAL SINGH

Establishing a comprehensive baseline estimate of sources, stocks and flows of plastic pollution, and then projecting into the future, has been an immense task. When it comes to solid waste, the availability, accuracy and international compatibility of data is notoriously insufficient.

Plastic items occur throughout the world in tens of thousands of shapes, sizes, polymer types and additive combinations. There are also considerable differences in cultural attitudes towards the way waste is managed, how plastic products are consumed, and the types of infrastructure and equipment used to manage it when it becomes waste.

Our modelling effort was a delicate and tedious exercise of simplifying and generalising this complexity. To understand how reliable, accurate, and precise our findings are likely to be, think of the first models that estimated how sensitive the climate is to human influence back in the 1970s.

Hopefully, the strong evidence base we have presented today will inform a global strategy and strong local preventive action. The plastic pollution challenge can be substantially controlled within a generation’s time. So, is anyone ready to act?The Conversation

Costas Velis, Lecturer in Resource Efficiency Systems, University of Leeds and Ed Cook, Research Fellow in Circular Economy Systems, University of Leeds

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How to cut your fuel bill, clear the air and reduce emissions: stop engine idling



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Robin Smit, University of Technology Sydney and Clare Walter, The University of Queensland

The transport sector is Australia’s second-largest polluter, pumping out almost 20% of our total greenhouse gas emissions. But everyday drivers can make a difference.

In particular, the amount of time you let your car engine idle can have a significant impact on emissions and local air quality. Engine idling is when the car engine is running while the vehicle is stationary, such as at a red light.

Opting for a bike is a great way to reduce your carbon footprint.
Shutterstock

A new Transport Energy/Emission Research report found in normal traffic conditions, Australians likely idle more than 20% of their drive time.

This contributes 1% to 8% of total carbon dioxide emissions over the journey, depending on the vehicle type. To put that into perspective, removing idling from the journey would be like removing up to 1.6 million cars from the road.




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Excessive idling (idling for longer than five minutes) could increase this contribution further, particularly for trucks and buses. When you also consider how extensive idling may create pollution hot spots around schools, this isn’t something to take lightly.

Pollution hot spots

Reducing idling doesn’t just lower your carbon footprint, it can also lower your fuel costs up to 10% or more.

Drivers simply have to turn their engines off while parked and wait in their vehicle. Perhaps crack open a window to maintain comfortable conditions, rather than switching on the air conditioner.

Some idling is unavoidable such as waiting for a traffic light or driving in congested conditions, but other idling is unnecessary, such as while parked.




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When many cars are idling in the same location, it can create poor local air quality. For example, idling has been identified overseas as a significant factor in higher pollution levels in and around schools. That’s because parents or school buses don’t turn off their engines when they drop off their kids or wait for them outside.

Parked you car? Turn off the engine.
Shutterstock

Even small reductions in vehicle emissions can have health benefits, such as reducing asthma, allergies and systemic inflammation in Australian children. In 2019, Australian researchers identified that even small increases of exposure to vehicle pollution were associated with an increased risk of childhood asthma and reduced lung function.

Anti-idling campaigns make a difference

Overseas studies show anti-idling campaigns and driver education can help improve air quality around schools, with busses and passenger cars switching off their engines more frequently.

In the US and Canada, local and state governments have enacted voluntary or mandatory anti-idling legislation, to address complaints and reduce fuel use, emissions and noise.

The results have been promising. In California, a range of measures – including anti-idling policies – aimed at reducing school children’s exposure to vehicle emissions were linked to the development of larger, healthier lungs in children.




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But in Australia, we identified almost no anti-idling initiatives or idle reduction legislation, despite calls for them in 2017.

However, “eco-driving”, as well as a promising new campaign called “Idle Off” is poised to roll out to secondary school students in Australia.

What about commercial vehicles?

Commercial vehicles can idle for long periods of time. In the US, typical long-haul trucks idle an estimated 1,800 hours per year when parked at truck stops, although a significant range of between 1,000 and 2,500 hours per year has also been reported.




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Fleet operators and logistics companies are therefore in a good position to roll out idle reduction initiatives and save on operating (fuel) costs while reducing emissions.

In fact, fleet operators overseas have actively sought to reduce idling emissions. This is not surprising as fuel costs are the second-largest expense for fleets, behind driver wages, typically accounting for 20% of a trucking fleet’s total operating costs.

The transport sector contributes 18.8% of Australia’s total emissions.
Shutterstock

Various technologies are available overseas that reduce idling emissions, such as stop-start systems, anti-idling devices (trucks) and battery electric vehicles.

But unlike other developed countries, Australia doesn’t have fuel efficiency or carbon dioxide emission standards. This means vehicle manufacturers have no incentive to include idle reduction technologies (or other fuel-saving technologies) in vehicles sold in Australia.

For example, the use of stop-start systems is rapidly growing overseas, but it’s unclear how many stop-start systems are used in new Australian cars.

Emission reduction technologies also come with extra costs for the vehicle manufacturer, making them less appealing, although cost benefits of reduced fuel use would pass on to consumers. This situation probably won’t change unless mandatory emission standards are implemented.

In any case, it’s easy for drivers to simply turn the key and shut down the engine when suitable. Reducing idling doesn’t require technologies.

Reducing your carbon footprint

If reducing emissions or saving money at the fuel bowser is not enough incentive, then perhaps, in time, exposing children to unnecessary idling emissions will be regarded in the same socially unacceptable light as smoking around children.




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And of course, there are other measures to reduce your transport carbon footprint. Drive a smaller car, and avoid diesel cars. Despite their reputation, Australian diesel cars emit, on average, about 10% more carbon dioxide per kilometre than petrol cars.

Or better yet, where possible, dust off that push bike, or walk.The Conversation

Robin Smit, Adjunct associate professor, University of Technology Sydney and Clare Walter, PhD Candidate, Honorary Research Fellow, Advocacy Consultant., The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

More than 1,200 tonnes of microplastics are dumped into Aussie farmland every year from wastewater sludge


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Abbas Mohajerani, RMIT University

Every year, treated wastewater sludge called “biosolids” is recycled and spread over agricultural land. My recent research discovered this practice dumps thousands of tonnes of microplastics into farmlands around the world. In Australia, we estimate this amount as at least 1,241 tonnes per year.

Microplastics in soils can threaten land, freshwater and marine ecosystems by changing what they eat and their habitats. This causes some organisms to lose weight and have higher death rates.

But this is only the beginning of the problem. Microplastics are good at absorbing other pollutants – such as cadmium, lead and nickel – and can transfer these heavy metals to soils.

Wastewater treatment plants create biosolids, which are packed full of microplastics and toxic chemicals.
Shutterstock

And while microplastics alone is an enormous issue, other contaminants have also been found in biosolids used for agriculture. This includes pharmaceutical chemicals, personal care products, pesticides and herbicides, surfactants (chemicals used in detergents) and flame retardants.

We must stop using biosolids for farmlands immediately, especially when alternative ways to recycle wastewater sludge already exist.

Where do the microplastics come from?

Biosolids are mainly a mix of water and organic materials.

But many household items that contain microplastics – such as lotions, soaps, facial and body washes, and toothpaste – end up in wastewater, too. Other major sources of microplastics in wastewater are synthetic fibres from clothing, plastics in the manufacturing and processing industries, and the breakdown of larger plastic debris.

Before they’re taken to farmlands, wastewater collection systems carry all, or most, of these microplastics and other chemicals from residential, commercial and industrial sources to wastewater treatment plants.

To determine the weight of microplastics in Australia and other countries, my data analysis used the average minimum and maximum numbers of microplastics particles, per kilogram of biosolids samples, found in Germany, Ireland and the USA.




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Australia produced 371,000 tonnes of biosolids in 2019. And globally, we estimate between 50 to more than 100 million tonnes of biosolids are produced each year.

Why microplastics are harmful

Microplastics in soil can accumulate in the food web. This happens when organisms consume more microplastics than they lose. This means heavy metals attached to the microplastics in soil organisms can progress further up the food chain, increasing the risk of human exposure to toxic heavy metals.

When microplastics accumulate heavy metals, they transfer these contaminants to plants and crops, such as rice and grains, as biosolids are spread over farmland.




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After a storm, microplastics in Sydney’s Cooks River increased 40 fold


Over time, microplastics break down and become even tinier, creating nanoplastics. Crops have also been shown to absorb nanoplastics and move them to different plant tissues.

Our research results also show that after the wastewater treatment process, the absorption potential of microplastics for metals increases.

The metal cadmium, for example, is particularly susceptible to microplastics in biosolids and can be transported to plant cells. Research from 2018 showed microplastics in biosolids can absorb cadmium ten times more than virgin microplastics (new microplastics that haven’t gone through wastewater treatment).

Biosolids have a cocktail of nasty chemicals

It’s not just plastic – many industrial additives and chemicals have been found in wastewater and biosolids.

This means they may accumulate in soils and affect the equilibrium of biological systems, with negative effects on plant growth. For example, researchers have found pharmaceutical chemicals in particular can reduce plant growth and inhibit root elongation.




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Other chemical contaminants – such as PFCs, PFAS and BPA – have likewise been detected in biosolids.

The effects these chemicals have on plants may lead to problems further down the food chain, such as humans and other animals inadvertently consuming pharmaceuticals and harmful chemicals.

What can we do about it?

Given the cocktail of toxic chemicals, heavy metals and microplastics, using biosolids in agricultural soils must be stopped without delay.

The good news is there’s another way we can recycle the world’s biosolids: turning them into sustainable fired-clay bricks, called “bio-bricks”.

Bricks incorporated with biosolids are a sustainable solution to an environmental problem.
RMIT media, Author provided

My team’s research from last year found bio-bricks a sustainable solution for both the wastewater treatment and brick manufacturing industries.

If 7% of all fired-clay bricks were biosolids, it would redirect all biosolids produced and stockpiled worldwide annually, including the millions of tonnes that currently end up in farmland each year.




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We also found they’d be more energy efficient. The properties of these bio-bricks are very similar to standard bricks, but generally requires 12.5% less energy to make.

And generally, comprehensive life-cycle assessment has shown biosolid bricks are more environmentally friendly than conventional bricks. These bricks will reduce or eliminate a significant source of greenhouse gas emissions from biosolids stockpiles and will save some virgin resources, such as clay soil and water, for the brick industry.

Now, it’s up to the agriculture, wastewater and brick industries, and governments to make this important transition.The Conversation

Abbas Mohajerani, Associate Professor, School of Engineering, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

After a storm, microplastics in Sydney’s Cooks River increased 40 fold



A litter trap in Cook’s River.
James HItchcock, Author provided

James Hitchcock, University of Canberra

Each year the ocean is inundated with 4.8 to 12.7 million tonnes of plastic washed in from land. A big proportion of this plastic is between 0.001 to 5 millimetres, and called “microplastic”.

But what happens during a storm, when lashings of rain funnel even more water from urban land into waterways? To date, no one has studied just how important storm events may be in polluting waterways with microplastics.




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So to find out, I studied my local waterway in Sydney, the Cooks River estuary. I headed out daily to measure how many microplastics were in the water, before, during, and after a major storm event in October, 2018.

The results, published on Wednesday, were startling. Microplastic particles in the river had increased more than 40 fold from the storm.

Particles of plastic found in rivers. They may be tiny, but they’re devastating to wildlife in waterways.
Author provided

To inner west Sydneysiders, the Cooks River is known to be particularly polluted. But it’s largely similar to many urban catchments around the world.

If the relationship between storm events and microplastic I found in the Cooks River holds for other urban rivers, then the concentrations of microplastics we’re exposing aquatic animals to is far higher than previously thought.

14 million plastic particles

They may be tiny, but microplastics are a major concern for aquatic life and food webs. Animals such as small fish and zooplankton directly consume the particles, and ingesting microplastics has the potential to slow growth, interfere with reproduction, and cause death.

Determining exactly how much microplastic enters rivers during storms required the rather unglamorous task of standing in the rain to collect water samples, while watching streams of unwanted debris float by (highlights included a fire extinguisher, a two-piece suit, and a litany of tennis balls).

Back in the laboratory, a multi-stage process is used to separate microplastics. This includes floating, filtering, and using strong chemical solutions to dissolve non-plastic items, before identification and counting with specialised microscopes.

Litter caught in a trap in Cooks River. These traps aren’t effective at catching microplastic.
Author provided

In the days before the October 2018 storm, there were 0.4 particles of microplastic per litre of water in the Cooks River. That jumped to 17.4 microplastics per litre after the storm.

Overall, that number averages to a total of 13.8 million microplastic particles floating around in the Cooks River estuary in the days after the storm.




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In other urban waterways around the world scientists have found similarly high numbers of microplastic.

For example in China’s Pearl River, microplastic averages 19.9 particles per litre. In the Mississippi River in the US, microplastic ranges from 28 to 60 particles per litre.

Where do microplastics come from?

We know runoff during storms is one of the main ways pollutants such as sediments and heavy metals end up in waterways. But not much is known about how microplastic gets there.

However think about your street. Wherever you see litter, there are also probably microplastics you cannot see that will eventually work their way into waterways when it rains.




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Many other sources of microplastics are less obvious. Car tyres, for example, which typically contain more plastic than rubber, are a major source of microplastics in our waterways. When your tyres lose tread over time, microscopic tyre fragments are left on roads.

Did you know your car tyres can be a major source of microplastic pollution?
Shutterstock

Microplastics may even build up on roads and rooftops from atmospheric deposition. Everyday, lightweight microplastics such as microfibres from synthetic clothing are carried in the wind, settling and accumulating before they’re washed into rivers and streams.

What’s more, during storms wastewater systems may overflow, contaminating waterways. Along with sewage, this can include high concentrations of synthetic microfibers from household washing machines.

And in regional areas, microplastics may be washing in from agricultural soils. Sewage sludge is often applied to soils as it is rich in nutrients, but the same sludge is also rich in microplastics.

What can be done?

There are many ways to mitigate the negative effects of stormwater on waterways.

Screens, traps, and booms can be fitted to outlets and rivers and catch large pieces of litter such as bottles and packaging. But how useful these approaches are for microplastics is unknown.

Raingardens and retention ponds are used to catch and slow stormwater down, allowing pollutants to drop to bottom rather than being transported into rivers. Artificial wetlands work in similar ways, diverting stormwater to allow natural processes to remove toxins from the water.

Almost 14 million plastic particles were floating in Cooks River after a storm two years ago.
Shutterstock

But while mitigating the effects of stormwater carrying microplastics is important, the only way we’ll truly stop this pollution is to reduce our reliance on plastic. We must develop policies to reduce and regulate how much plastic material is produced and sold.

Plastic is ubiquitous, and its production around the world hasn’t slowed, reaching 359 million tonnes each year. Many countries now have or plan to introduce laws regulating the sale or production of some items such as plastic bags, single-use plastics and microbeads in cleaning products.




Read more:
We have no idea how much microplastic is in Australia’s soil (but it could be a lot)


In Australia, most state governments have committed to banning plastic bags, but there are still no laws banning the use of microplastics in cleaning or cosmetic products, or single-use plastics.

We’ve made a good start, but we’ll need deeper changes to what we produce and consume to stem the tide of microplastics in our waterways.The Conversation

James Hitchcock, Post-Doctoral Research Fellow, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

NSW has approved Snowy 2.0. Here are six reasons why that’s a bad move



Lucas Coch/AAP

Bruce Mountain, Victoria University and Mark Lintermans, University of Canberra

The controversial Snowy 2.0 project has mounted a major hurdle after the New South Wales government today announced approval for its main works.

The pumped hydro venture in southern NSW will pump water uphill into dams and release it when electricity demand is high. The federal government says it will act as a giant battery, backing up intermittent energy from by wind and solar.

We and others have criticised the project on several grounds. Here are six reasons we think Snowy 2.0 should be shelved.

1. It’s really expensive

The federal government announced the Snowy 2.0 project without a market assessment, cost-benefit analysis or indeed even a feasibility study.

When former Prime Minister Malcolm Turnbull unveiled the Snowy expansion in March 2017, he said it would cost A$2 billion and be commissioned by 2021. This was revised upwards several times and in April last year, Snowy Hydro awarded a A$5.1 billion contract for partial construction.

Snowy Hydro has not costed the transmission upgrades on which the project depends. TransGrid, owner of the grid in NSW, has identified options including extensions to Sydney with indicative costs up to A$1.9 billion. Massive extensions south, to Melbourne, will also be required but this has not been costed.

The Tumut 3 scheme, with which Snowy 2.0 will share a dam.
Snowy Hydro Ltd

2. It will increase greenhouse gas emissions

Both Snowy Hydro Ltd and its owner, the federal government, say the project will help expand renewable electricity generation. But it won’t work that way. For at least the next couple of decades, analysis suggests Snowy 2.0 will store coal-fired electricity, not renewable electricity.

Snowy Hydro says it will pump the water when a lot of wind and solar energy is being produced (and therefore when wholesale electricity prices are low).




Read more:
Snowy 2.0 is a wolf in sheep’s clothing – it will push carbon emissions up, not down


But wind and solar farms produce electricity whenever the resource is available. This will happen irrespective of whether Snowy 2.0 is producing or consuming energy.

When Snowy 2.0 pumps water uphill to its upper reservoir, it adds to demand on the electricity system. For the next couple of decades at least, coal-fired electricity generators – the next cheapest form of electricity after renewables – will provide Snowy 2.0’s power. Snowy Hydro has denied these claims.

Khancoban Dam, part of the soon-to-be expanded Snowy Hydro scheme.
Snowy Hydro Ltd

3. It will deliver a fraction of the energy benefits promised

Snowy 2.0 is supposed to store renewable energy for when it is needed. Snowy Hydro says the project could generate electricity at its full 2,000 megawatt capacity for 175 hours – or about a week.

But the maximum additional pumped hydro capacity Snowy 2.0 can create, in theory, is less than half this. The reasons are technical, and you can read more here.

It comes down to a) the amount of time and electricity required to replenish the dam at the top of the system, and b) the fact that for Snowy 2.0 to operate at full capacity, dams used by the existing hydro project will have to be emptied. This will result in “lost” water and by extension, lost electricity production.



The Conversation, CC BY-ND

4. Native fish may be pushed to extinction

Snowy 2.0 involves building a giant tunnel to connect two water storages – the Tantangara and Talbingo reservoirs. By extension, the project will also connect the rivers and creeks connected to these reservoirs.

A small, critically endangered native fish, the stocky galaxias, lives in a creek upstream of Tantangara. This is the last known population of the species.

The stocky galaxias.
Hugh Allan

An invasive native fish, the climbing galaxias, lives in the Talbingo reservoir. Water pumped from Talbingo will likely transfer this fish to Tantangara.

From here, the climbing galaxias’ capacity to climb wet vertical surfaces would enable it to reach upstream creeks and compete for food with, and prey on, stocky galaxias – probably pushing it into extinction.

Snowy 2.0 is also likely to spread two other problematic species – redfin perch and eastern gambusia – through the headwaters of the Murrumbidgee, Snowy and Murray rivers.




Read more:
Snowy 2.0 threatens to pollute our rivers and wipe out native fish


5. It’s a pollution risk

Snowy Hydro says its environmental impact statement addresses fish transfer impacts, and potentially serious water quality issues.

Four million tonnes of rock excavated to build Snowy 2.0 would be dumped into the two reservoirs. The rock will contain potential acid-forming minerals and other harmful substances, which threaten to pollute water storages and rivers downstream.

When the first stage of the Snowy Hydro project was built, comparable rocks were dumped in the Tooma River catchment. Research in 2006 suggested the dump was associated with eradication of almost all fish from the Tooma River downstream after rainfall.

Snowy 2.0 threatens to pollute pristine Snowy Mountains rivers.
Schopier/Wikimedia

6. Other options were not explored

Many competing alternatives can provide storage far more flexibly for a fraction of Snowy 2.0’s price tag. These alternatives would also have far fewer environmental impacts or development risks, in most cases none of the transmission costs and all could be built much more quickly.

Expert analysis in 2017 identified 22,000 potential pumped hydro energy storage sites across Australia.

Other alternatives include chemical batteries, encouraging demand to follow supply, gas or diesel generators, and re-orienting more solar capacity to capture the sun from the east or west, not just mainly the north.

Where to now?

The federal government, which owns Snowy Hydro, is yet to approve the main works.

Given the many objections to the project and how much has changed since it was proposed, we strongly believe it should be put on hold, and scrutinised by independent experts. There’s too much at stake to get this wrong.




Read more:
Five gifs that explain how pumped hydro actually works


The Conversation


Bruce Mountain, Director, Victoria Energy Policy Centre, Victoria University and Mark Lintermans, Associate professor, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Seafloor currents sweep microplastics into deep-sea hotspots of ocean life



A rockfish hides in a red tree coral in the deep sea.
Geofflos

Ian Kane, University of Manchester and Michael Clare, National Oceanography Centre

What if the “great ocean garbage patches” were just the tip of the iceberg? While more than ten million tonnes of plastic waste enters the sea each year, we actually see just 1% of it – the portion that floats on the ocean surface. What happens to the missing 99% has been unclear for a while.

Plastic debris is gradually broken down into smaller and smaller fragments in the ocean, until it forms particles smaller than 5mm, known as microplastics. Our new research shows that powerful currents sweep these microplastics along the seafloor into large “drifts”, which concentrate them in astounding quantities. We found up to 1.9 million pieces of microplastic in a 5cm-thick layer covering just one square metre – the highest levels of microplastics yet recorded on the ocean floor.

While microplastics have been found on the seafloor worldwide, scientists weren’t sure how they got there and how they spread. We thought that microplastics would separate out according to how big or dense they were, in a similar manner to natural sediment. But plastics are different – some float, but more than half of them sink.




Read more:
Pristine Antarctic fjords contain similar levels of microplastics to open oceans near big civilisations


Plastics which once floated can sink as they become coated in algae, or if bound up with other sticky minerals and organic matter. Recent research has shown that rivers transport microplastics to the ocean too, and laboratory experiments revealed that giant underwater avalanches of sediment can transport these tiny particles along deep-sea canyons to greater depths.

We’ve now discovered how a global network of deep-sea currents transports microplastics, creating plastic hotspots within vast sediment drifts. By catching a ride on these currents, microplastics may be accumulating where deep-sea life is abundant.

Once plastic debris has broken down and sinks to the ocean floor, currents sweep the particles into vast drifts.
Ian Kane, Author provided

From bedroom floors to the seafloor

We surveyed an area of the Mediterranean off the western coast of Italy, known as the Tyrrhenian Sea, and studied the bottom currents that flow near the seafloor. These currents are driven by differences in water salinity and temperature as part of a system of ocean circulation that spans the globe. Seafloor drifts of sediment can be many kilometres across and hundreds of metres high, forming where these currents lose their strength.

We analysed sediment samples from the seafloor taken at depths of several hundred metres. To avoid disturbing the surface layer of sediment, we used samples taken with box-cores, which are like big cookie cutters. In the laboratory, we separated microplastics from the sediment and counted them under microscopes, analysing them using infra-red spectroscopy to find out what kinds of plastic polymer types were there.

A microplastic fibre seen under a microscope.
Ian Kane, Author provided

Most microplastics found on the seafloor are fibres from clothes and textiles. These are particularly insidious, as they can be eaten and absorbed by organisms. Although microplastics on their own are often non-toxic, studies show the build-up of toxins on their surfaces can harm organisms if ingested.

These deep ocean currents also carry oxygenated water and nutrients, meaning that the seafloor hotspots where microplastics accumulate may also be home to important ecosystems such as deep-sea coral reefs that have evolved to depend on these flows, but are now receiving huge quantities of microplastics instead.

What was once a hidden problem has now been uncovered – natural currents and the flow of plastic waste into the ocean are turning parts of the seafloor into repositories for microplastics. The cheap plastic goods we take for granted eventually end up somewhere. The clothes that may only last weeks in your wardrobe linger for decades to centuries on the seafloor, potentially harming the unique and poorly understood creatures that live there.The Conversation

Ian Kane, Reader in Geology, University of Manchester and Michael Clare, Principal Researcher in Marine Geoscience, National Oceanography Centre

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Snowy 2.0 threatens to pollute our rivers and wipe out native fish



Schopier/Wikimedia

John Harris, UNSW and Mark Lintermans, University of Canberra

The federal government’s Snowy 2.0 energy venture is controversial for many reasons, but one has largely escaped public attention. The project threatens to devastate aquatic life by introducing predators and polluting important rivers. It may even push one fish species to extinction.

The environmental impact statement for the taxpayer-funded project is almost 10,000 pages long. Yet it fails to resolve critical problems, and in one case seeks legal exemptions to enable Snowy 2.0 to wreak environmental damage.

The New South Wales government is soon expected to grant the project environmental approval. This process should be suspended, and independent experts should urgently review the project’s environmental credentials.

Native fish extinctions

Snowy Hydro Limited, a Commonwealth-owned corporation, is behind the Snowy 2.0 project in the Kosciuszko National Park in southern NSW. It involves building a giant tunnel to connect two water storages – the Tantangara and Talbingo reservoirs. By extension, the project will also connect the rivers and creeks connected to these reservoirs.

A small, critically endangered native fish, the stocky galaxias, lives in a creek upstream of Tantangara. This is the last known population of the species.




Read more:
Snowy 2.0 is a wolf in sheep’s clothing – it will push carbon emissions up, not down


An invasive native fish, the climbing galaxias, lives in the Talbingo reservoir (it was introduced from coastal streams when the original Snowy project was built). Water pumped from Talbingo will likely transfer this fish to Tantangara.

From here, the climbing galaxias’ capacity to climb wet vertical surfaces would enable it to reach upstream creeks and compete for food with, and prey on, stocky galaxias – probably pushing it into extinction.

The stocky galaxias.
Hugh Allan

Snowy Hydro has applied for an exemption under NSW biosecurity legislation to permit the transfer of the climbing galaxias and two other fish species: the alien, noxious redfin perch and eastern gambusia.

Redfin perch compete for food with other species and produce many offspring. They are voracious, carnivorous predators, known to prey on smaller fish.

Redfin perch also allow the establishment of a fatal fish disease – epizootic haematopoietic necrosis virus – or EHN. This disease kills the endangered native Macquarie perch, the population of which below Tantangara is one of very few remaining.

If Snowy 2.0 is granted approval, it is likely to spread these problematic species through the headwaters of the Murrumbidgee, Snowy and Murray rivers.

The climbing galaxias, which threatens the native stocky galaxias.
Stella McQueen/Wikimedia

Acid and asbestos pollution

Four million tonnes of rock excavated to build Snowy 2.0 would be dumped into the two reservoirs. Snowy Hydro has not assessed the pollution risks this creates. The rock will contain potential acid-forming minerals and a form of asbestos, which threaten to pollute water storages and rivers downstream.

When the first stage of the Snowy Hydro project was built, comparable rocks were dumped in the Tooma River catchment. Research in 2006 suggested the dump was associated with eradication of almost all fish from the Tooma River downstream after rainfall.




Read more:
Snowy 2.0 will not produce nearly as much electricity as claimed. We must hit the pause button


Addressing the problems

The environmental impact statement either ignores, or pays inadequate attention to, these environmental problems.

For example, installing large-scale screens at water inlets would be the best way to prevent fish transfer from Talbingo Dam, but Snowy Hydro has dismissed it as too costly.

Snowy Hydro instead proposes a dubious second-rate measure: screens to filter pumped flows leaving Tantangara reservoir, and building a barrier in the stream below the stocky galaxias habitat.

The best and cheapest way to prevent damage from alien species is stopping the populations from establishing. Trying to control or eradicate pest species once they’re established is far more difficult and costly.



The Conversation, CC BY-ND

We believe the measures proposed by Snowy Hydro are impractical. It would be very difficult to maintain a screen fine and large enough to prevent fish eggs and larvae moving out of Tantangara reservoir and such screens would be totally ineffective at preventing the spread of EHN virus.

A six metre-high waterfall downstream of the stocky galaxias habitat currently protects the critically endangered species from other invasive species threats. But climbing galaxias have an extraordinary ability to ascend wet surfaces. They would easily climb the waterfall, and possibly the proposed creek barrier as well.

Such an engineered barrier has never been constructed in Australia. We are informed that in New Zealand, the barriers have not been fully effective and often require design adjustments.




Read more:
The government’s electricity shortlist rightly features pumped hydro (and wrongly includes coal)


Even if the barrier protected the stocky galaxias at this location, efforts to establish populations in other unprotected regional streams would be severely hampered by the spread of climbing galaxias.

Preventing redfin and EHN from entering the Murrumbidgee River downstream of Tantangara depends on the reservoir never spilling. The reservoir has spilled twice since construction in the 1960s, and would operate at much higher water levels when Snowy 2.0 was operating. Despite this, Snowy Hydro says it has “high confidence in being able to avoid spill”.

If dumped spoil pollutes the two reservoirs and Murrumbidgee and Tumut rivers, this would also have potentially profound ecological impacts. These have not been critically assessed, nor effective prevention methods identified.

The Tumut 3 scheme, part of the existing Snowy Hydro scheme.
Snowy Hydro Ltd

Looking to the future

Snowy 2.0 will likely make one critically endangered species extinct and threaten an important remaining population of another, as well as pollute freshwater habitats. As others have noted, the project is also questionable on other environmental and economic grounds.

These potential failures underscore the need to immediately halt Snowy 2.0, and subject it to independent expert scrutiny.


In response to the issues raised in this article, a spokesperson for Snowy Hydro said:

“Snowy Hydro’s EIS, supported by numerous reports from independent scientific experts, extensively address potential water quality and fish transfer impacts and the risk mitigation measures to be put in place. As the EIS is currently being assessed by the NSW Government we have no further comment.”


A previous version of this article incorrectly stated that water pumped from Tantangara will likely transfer fish to Talbingo. It should have said water pumped from Talbingo will likely transfer fish to Tantangara.The Conversation

John Harris, Adjunct Associate Professor, Centre for Ecosystem Science, UNSW and Mark Lintermans, Associate professor, University of Canberra

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Polluted, drained, and drying out: new warnings on New Zealand’s rivers and lakes



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Troy Baisden, University of Waikato

The latest environmental report on New Zealand’s lakes and rivers reiterates bleak news about the state of freshwater ecosystems, and warns that climate change will exacerbate existing threats.

Almost all New Zealand rivers running through urban and farming areas (95-99%) carry pollution above water quality guidelines, while most of the nation’s wetlands (90%) have been drained, and many freshwater fish species (76%) are threatened or at risk.

The most significant pressures on freshwater ecosystems fit into four issues:


Ministry for the Environment/Stats NZ, CC BY-SA

Climate change gets more attention than in earlier assessments, reflecting the fact that glaciers are already shrinking and soils are drying out.




Read more:
New Zealand’s urban freshwater is improving, but a major report reveals huge gaps in our knowledge


What whitebait tell us about freshwater fish under stress

The latest assessment is an update on a freshwater report in 2017 and the comprehensive Environment Aotearoa 2019. It reiterates issues we’ve seen before, but begins to implement recent recommendations by the Parliamentary Commissioner for the Environment (PCE) calling for a stronger link between data and environmental management.

Biological impacts are at the forefront of this latest assessment. It shows that a wide range of freshwater organisms are at risk. The statistics for freshwater fish are the most concerning, with three quarters of the 51 native species already either threatened or at risk of extinction.

The report uses a particular group of native fish (īnanga, or galaxids) to connect the multiple impacts humans have, across a range of habitats at different life stages.

Īnanga are better known as whitebait, a delicacy that is a mix of juveniles from six different species caught as they migrate from the sea to rivers.

Whitebait is considered a delicacy in New Zealand.
Shutterstock

Īnanga of different ages and species live in different habitats, so they can be used to represent the issues facing a range of freshwater fish across ecosystems. The main stress factors include altered habitat, pollution and excess nutrients, water use for irrigation and climate change.

Climate change is expected to exacerbate existing stresses native organisms like īnanga face and protecting their habitat means understanding how much it will reduce water flows and create hotter and drier conditions.

Filling gaps in understanding

The use of organisms to assess environmental change, including climate change impacts, is an obvious but important step. It makes it possible to consider climate change in a way that meets the Environmental Reporting Act’s requirement to report on a “body of evidence”.

This latest report responds to the PCE’s concerns about gaps in our knowledge, which were raised in the Environment Aotearoa 2019 assessment. The new strategy for filling large holes in our knowledge has three priorities: knowing and monitoring what we have, what we may lose, and where or how we can make changes.




Read more:
Six ways to improve water quality in New Zealand’s lakes and rivers


The report highlights that mātauranga Māori, the process of using indigenous knowledge about the environment, can fill some gaps in data or add insights. Other methods and models, such as nutrient budget scenarios, also deserve consideration.

There is some good news as well. Some pollution concerns may be minor or limited to very small areas. This includes several so-called emerging contaminants, such as fire retardants, which have been discovered in groundwater around airfields but are now banned or restricted.

The second piece of good news is that new ways of studying the environment can help fill major gaps. For example, lakes may be more stable indicators of freshwater health than rivers and streams, but only 4% (about 150) of New Zealand’s 3,820 larger lakes are regularly monitored by regional councils.

For almost 300 lakes, the report includes an index of the plants that live in them, and for more than 3000 there is now an established method of estimating lake water quality. Further information is becoming available, using updated estimations, satellite data for the last 20 years and sediment cores to reconstruct environmental conditions over the last few hundred years.

Unfortunately, the data from lakes confirms the general trend of freshwater decline, but at least the multiple forms of complementary information should help us to manage New Zealand’s freshwater ecosystems better.The Conversation

Troy Baisden, Professor and Chair in Lake and Freshwater Sciences, University of Waikato

This article is republished from The Conversation under a Creative Commons license. Read the original article.