Australians are washing microplastics down the drain and it's ending up in fields.

Different microplastic particles from bisolid samples can be seen under a microscope. Credit: Sheema Ziahrumi

Australian wastewater treatment plants produce thousands of tonnes of sewage sludge each year. This nutrient-rich material is then dried to form “biosolids,” which are used to fertilize agricultural soils.

Unfortunately, every kilogram of biosolids also contains thousands of tiny pieces of plastic. These pieces are so small that they can only be seen under a microscope, so they are called Microplastics.

I Our new research, we sampled biosolids from three states and calculated the average contribution of microplastics per person: 3 g in New South Wales and 4.5 g in Queensland. But the average in South Australia was 11.5 grams — the same amount of plastic as a plastic bag.

About 80 percent of this microplastic comes from laundry. We need to protect. Prevent pollution by making simple changes at home, mandating filters on washing machines and introducing more efficient wastewater treatment.

Biosolids as fertilizers

Most household wastewater comes from household kitchens, bathrooms, and laundries.

Wastewater treatment separates most of the water and leaves the sewage sludge behind. This mixture of water and organic material can then be sent to a landfill for disposal or dried to create a material called “biosolids”.

In Australia, two-thirds Annual production of 340,000 metric tons Used in fields to improve soil quality and accelerate plant growth. This not only increases agricultural productivity but also allows for more sustainable disposal of treated sewage sludge. Instead of ending up in landfill, the waste becomes a resource, a useful and economically viable fertilizer.

Microplastics in Australian biosolids

Wastewater treatment plants can catch from anywhere. 60% to more than 90% of microplastics in sewage before discharge to wastewater. But plastic is durable and does not deteriorate during treatment. So Dewatered wastewater is easily transferred to sludge.

We assessed the abundance, characteristics and size ranges of microplastics in biosolids collected from 13 In three states

We found that every kilogram of bisolid contains 11,000 to 150,000 microplastic particles.

Most of the microplastics found were invisible to the naked eye, ranging in size from 20 to 200 micrometers.

The most common type of microplastic was microfibers made from fabric. We found more microplastic fibers in winter. We suspect this is similar to people washing more synthetic fleece clothes and blankets.

Microbeads are tiny balls of microplastic that are sometimes added to personal care products and soaps. We found no microbeads in samples from South Australia and New South Wales. These states were among the first to support. Voluntary industry steps up from plastic microbeads.

In contrast, we found small amounts of microbeads in the Queensland samples, which were only Microbeads were banned in September last year.. This was more than a year after the samples were collected for this study.

We estimate that Australians release between 0.7g and 21g of microplastics into wastewater each year. This wide range is based on our results, which varied by state: 0.7g to 5.9g in NSW, 1g to 7.2g in Queensland and 1.9g to 21g in SA. We don’t know why it varies so much between states.

This contributes to the amount of microplastics in biosolids. Our biosolids samples contained between 1 kg and 17 kg of microplastics per metric ton. Remember this is being transferred to our fields.

What is the problem?

Microplastics are persistently accumulating in agricultural soils, where they will remain for hundreds of years. While natural weathering processes such as sun and rain will gradually break down microplastics into smaller and smaller particles, making matters worse. Smaller particles have more harmful effects on soil organisms.

Eating small pieces of plastic can cause internal irritation and blockages in the digestive system. In very small aquatic animals such as zooplankton, microplastics can reduce the absorption of nutrients from food. Reduces reproductive rate, and causes death..

These small particles also contain a. A cocktail of toxic chemicals, either added during manufacturing to improve the product or leached from the environment. It makes them. Even more dangerous.

Small are microplastics (less than 100 micrometers in size). Even more harmful to soil organisms.

Microplastics in soil can be ingested by soil organisms such as earthworms and have harmful effects on these important organisms. Exposure to microplastics has also been shown. Adversely affects soil health and plant growth..

Australian regulations Controls the amount of heavy metals, nutrients, pathogens and some emerging pollutants that are allowed in biosolids, but there are no guidelines for the concentration of microplastics. We think that has to change.

Here’s what we can do.

Our research shows that biosolids are an important source of microplastics in agricultural systems. More research is needed to better understand the risks.

We need to take effective control measures to reduce the accumulation of microplastics in productive agricultural lands.

The most effective way to do this is to reduce the level of microplastics in biosolids at the source.

We know that most of the microplastics in biosolids come from laundry. While it may not be possible to eliminate the use of synthetic fabrics, there are steps we can all take to reduce the amount of microplastics that wash our clothes into wastewater. Installed properly Filters in washing machines It has been shown to significantly reduce microplastic levels in wastewater.

of Australia National Plastics Plan The Australian government recommends working with industry to “phase in” microfiber filters on all washing machines by 2030. But why wait until 2030?

Multiple jurisdictions, including France, Ontario And Californiahas already made microfiber filters mandatory on washing machines. It’s about time Australia did the same.

In the meantime, there are simple things that everyone can do at home. Wash clothes in cold water, avoid running the machine for light loads if you can wait for a full load, and wash synthetics less often. These measures will also save energy and money.

Far better than this is to prevent microplastics from entering the wastewater stream. A wastewater treatment plant is trying to remove them.. Prevention is always better than cure.

Provided by

This article has been republished. Conversation Under Creative Commons License. read Original article.Conversation

Reference: Australians are washing microplastics down the drain and it’s ending up on farms (2024, February 18) Retrieved February 18, 2024 from https://phys.org/news/2024-02-australians-microplastics-farms.html Obtained

This document is subject to copyright. No part may be reproduced without written permission, except for any fair dealing for the purpose of private study or research. The content is provided for informational purposes only.