Wednesday, 23 September 2020

New on Netflix - A documentary called "Kiss the Ground"

 New on Netflix - A documentary called "Kiss the Ground"

The film has a lot of great ideas (no till, cover crops, biodiversity, compost (the real kind) etc. but sadly presents the idea of using sewage sludge / biosolids in a very superficial and naïve way.

Starting just after the first hour, 1:05 the film looks at composting poop in Haiti. The narrator makes the classic mistake of asserting that humanure and "biosolids" from cities is somehow the same thing. As she says -
"most people don't know that all across America, if you buy some potting mix, it probably has biosolids in it, and that comes from human sewage. We eat food, and we poop it out. We can then treat it, and create soil that has good content for plants, and then the cycle just goes around and around."

No mention is made about what is actually in these "biosolids" from these cities in America (or indeed any city in the world) - is NOT just human excrement - it is a concentration of all domestic and industrial pollutants that go down drains and sewers. It has some good stuff in it, which plants can use, but also thousands of other contaminants.

No mention is made of the fact that this so-called “treatment” does little or nothing to deal with some of the most alarming pollutants found in "biosolids" - things like - Antibiotic Resistance Genes, pharmaceuticals, flame retardants, PFAS, microplastics and phthalates

As Prof. Jordan Peccia- of Yale University, has noted - " biosolids contain heavy metals, hazardous organic chemicals, microbial pathogens, and antibiotic resistant bacteria ... polybrominated flame retardants, pharmaceuticals like Prozac and Tagamet, human hormones such as estrogen, antibiotics, narcotics"

Farms across America are being used as sinks for our cities' toxic sewage waste. It is being spread under the pretense that it is somehow magically "compost" - it is not - it is Toxic Sewage Waste - very different from simple humanure.

As microbiologist, Dr. Sierra Rayne has written - "The science doesn't support the disposal of sewage sludge across the landscape. The supposed benefits are more than offset by the risks to human and environmental health .An unimaginably large number of chemical and biological contaminants exist in these materials, and they persist in the product up to, and after, land disposal. Scientific investigations have identified only a tiny fraction of the total contaminant load. We cannot even say with any degree of confidence what the true range of contaminant risk is from the sludge ... Governments are playing Russian roulette with sewage sludge. Over time, there is a high probability this game will be lost at the public's expense."

Biosolids have NO PLACE in Regenerative or Sustainable Agriculture.
"The most comprehensive sludge management studies have shown that land application is an important contribution to global warming, eutrophication, and acidification" see -

Tuesday, 8 September 2020

Issues related to the "land application" of sewage sludge (biosolids)


Recent worrying science around the "land application" of sewage sludge (biosolids)

Microplastics In Farm Soils Have Adverse Effects On Wheat Crops

"Microplastics in soils have recently been linked to increased cadmium uptake and root damage in wheat plants ... microplastics were able to damage the roots of the wheat plants by clogging soil pores and preventing water uptake"

("The highest source of microplastic input into the soil is the direct application of sewage sludge for agricultural fertilization")

Monday, 15 June 2020

Environment Agency report finds biosolids contaminated with multiple pollutants

UK Environment Agency report finds sewage sludge destined for farms contaminated with multiple pollutants

Below are some of the highlights from the new report -

On the composition of Sewage Sludge / Biosolids - 

“There is growing skepticism whether land application of sewage sludge is a sustainable method of dealing with that waste stream. The underlying concerns for these actions result in particular from the fact that the majority of contaminants in general and organic contaminants in particular potentially contained in sewage sludge are not known and not sufficiently tested before applying sludge on land. An extensive and meaningful risk assessment would require however full knowledge of the number, the concentration and the effects of all organic contaminants found in sewage sludge. Filling the gaps in knowledge regarding the concentration, fate and toxicity of sludge-borne contaminants is critical if risks associated with land application are to be adequately characterized”.
"in addition to organic waste material there are traces of other substances, some of which can be toxic to humans and animals at elevated concentrations in the soil or in food. The composition of sludge is thought to be becoming increasingly complex"

"Smith (2009) identified the following compounds, which may be incorporated in sewage sludge:
·persistent compounds from incomplete combustion of fossil fuels that enter the urban wastewater collection system through deposition onto paved surfaces via run-off (e.g. polycyclic aromatic hydrocarbons (PAHs) and dioxins / furans);
·persistent compounds that are associated with impurities in wood preservatives such as creosote (PAHs) and pentachlorophenol (PCP) that enter urban wastewater in run-off;
·controlled persistent compounds mobilized by volatilisation from soil, deposition and transfer to urban wastewater in run-off (e.g. PAHs, PCBs and dioxins / furans);
persistent compounds generated by cooking food that are discharged from domestic sources
(e.g. PAHs);
·persistent compounds that are prohibited from use/manufacture, but domestic sources may exist and can transfer to urban wastewater via run-off (e.g. chlorinated pesticides);
·compounds discharged to sewer used directly in industrial processes or domestically, including solvents, flame retardants or compounds that leach from plastics and surfaces during end-use and are carried in run-off (e.g. di(2-ethylhexyl)phthalate (DEHP) and polybrominated diphenyl ethers (PBDEs));
detergent residues (e.g. linear alkylbenzene sulphonates, nonylphenol and nonylphenol
·pharmaceuticals, antibiotics, endogenous hormones and synthetic steroids; and,

·compounds from the various above groups with endocrine-disrupting potential.

Microplastics are also a growing concern. These can be split into two groups (CIWEM, 2017):
·primary microplastics include industrial scrubbers used in blast cleaning, plastic powders used in moulding, nanoparticles used in industrial processes and micro-beads used in cosmetics and personal care products. Soaps are a major source of microbeads both in personal care products (e.g. deodorant, shampoo, conditioner, shower gel, lipstick, hair colouring, shaving cream, sunscreen, insect repellent, anti-wrinkle creams, moisturizers, hair spray, facial masks, baby care products, eye shadow, mascara) and in detergents for washing machines;  

-and secondary microplastics formed by fragmentation and weathering of larger plastic items during the use of products such as textiles (including microfleece materials), paint and tyres, or once these or other plastic items (bags, bottles etc.) have been released into the environment.

Most microplastic emissions occur in urban and residential areas. In developed regions,
municipal/industrial effluents and even diffuse urban runoff are eventually conveyed to wastewater treatment works. Additives used in manufacture include, PCBs, polybrominated diphenyl ethers (PBDEs), perfluorooctanoic acid (PFOA), bis-phenol A (BPA) and phthalate plasticisers. Microplastics could also provide a medium for exotic species and pathogens, for example microorganisms developing biofilms on microplastics particles. (UNEP, 2015).
During wastewater treatment, over 90% of microplastics are retained in sewage sludge (Carr, 2016). Most of the plastic ingredients in microplastics contain non-degradable polymers, which may take hundreds of years to degrade completely via oxidative or photodegradation routes (UNEP, 2015). In most urban and domestic environments, the contact time for these chemicals with human users will be in the order of minutes to days, with most of the chemical residues following usage being washed into sewers. However, once partitioned into sludge and spread to land, the residence time for some of the more persistent chemicals in agricultural soils can be many years. Sludge also contains bacteria and viruses, which are a potential hazard to the health of humans, animals and plants"

"The assessment indicated potential risks to human health from the following POP: benzo(a)pyrene, dioxins, furans and dioxin-like PCBs, plus PTE manganese.
There were also potential issues with enrichment of a wider range of PTE and POP, which may indicate that long term spreading of sludges at the modelled rates could result in accumulation of these contaminants to levels which may pose a risk"

Potential Risks

Risks to human health or environmental receptors as a result of waste material applied to land can be categorized as:
·contamination of soil by substances harmful to human health, crops or livestock;
·contamination of groundwater by substances harmful to human health or ecological receptors;
·contamination of surface water by substances harmful to human health or ecological receptors;
·contamination of the food chain by substances harmful to human or animal health; or

·reduction in the agricultural productivity of land.

A further limitation is that for many of the emerging toxics, not enough is understood about the toxicity and behaviour of these contaminants in the environment to derive suitable risk assessment criteria which are protective of human health, crops, livestock, controlled waters, and the wider environment.

The contaminants present in materials applied to land can be broadly categorised as:
·potentially toxic elements (PTEs), predominantly metals, which have long been recognised as hazards and which are typically included in the thresholds for compost and sludge;
·other inorganic compounds (e.g. various anions and nutrients) which may affect soil quality or agricultural productivity, or which may affect biological processes.
organic contaminants, many of which are persistent in the environment and some of which may bioaccumulate. Some of these chemicals are widely recognised as hazards (e.g. dioxins and PAHs) and are often analysed for in wastes, although are not included in the thresholds for compost, digestate and sludge. Others, such as PFAS and pharmaceutical residues, are not routinely analysed and do not have well-established thresholds;
·physical contaminants such as glass and plastics, which may pose health and safety risks, and in the case of plastics and microplastics release chemicals of concern upon degradation and breakdown; and
·asbestos, the health risks for which are well known.

Organic Contaminants

“organic compounds are present in many of the materials that are ultimately applied to land, and in many cases these are of anthropogenic origin.
The diversity of materials and their sources of origin makes it difficult to make definitive assessments at this stage of how these compounds find their way into certain materials. Some (such as PAHs and PCBs) seem to be ubiquitous, albeit at usually low concentrations. The absence of regulatory thresholds for many compounds means that it is difficult to determine whether non-detects (at current detection levels) are actually indicative of negligible risk.

It is also worth noting that the relative half-life of the compounds when assessing risk is important. For example, volatile aromatic compounds (e.g. toluene) may be present in waste at low levels but are anticipated to break down relatively quickly in soil, whereas other compounds such as PCBs, PBDEs, PFOS, dioxins and furans have very long half-lives in soil and can last for years. With these persistent chemicals of concern, there is the possibility for accumulation in soil and bioaccumulation in animals and humans ingesting grass and crops grown on the soil. Based on the M2L and WEP studies, the most widespread organic contaminants in wastes includes:
·dioxins and furans;
·triclosan; and


“The potential presence of microplastics in wastewater is becoming a concern, as these can then become incorporated into biosolids and sewage sludge which is then spread to land.
Microplastics can potentially impact soil ecosystems, crops and livestock either directly or through the toxic and endocrine-disrupting substances added during plastics manufacturing.
During use, plasticpolymers efficiently accumulate other harmful pollutants from the surrounding environment, including a number of persistent, bioaccumulative and toxic substances, e.g. PCBs, dioxins, DDTs and PAHs (Nizetto, 2016). As yet, there is no standardised method for assessing the levels of microplastics in wastewaters, sludges and soils and consequently the presence of microplastics in wastes and agricultural soils was not assessed and the full potential extent of the issue has not been properly assessed.
...the possible presence of plastics can be inferred from the detection of

certain organic contaminants present in plastics (e.g. phthalates, used as plasticisers), but the presence of micro-plastics and whether or not these are acting as “sponges” for adsorption of other organic contaminants is not clear.

"the cumulative effect of enrichment from multiple applications of waste over a number of
years has yet to be assessed, Currently, the guidance in the regulations requires analysis of
PTE (potentially toxic elements ) concentrations in receiving soils once every twentieth year.
The levels of enrichment identified for individual spreading events are sufficiently high that
year on year applications could result in significant increases in PTE concentrations in the 20 year period between testing, to the extent that the soil may no longer be suitable for supporting crop growth.

In addition, the PTE suite does not include all of the potential contaminants present in waste which may pose a risk to human health, controlled waters, and the wider environment.

Ecological risks were assessed by screening soil concentrations against Soil Screening Values (SSV) derived for assessing potential risks to ecological systems from 11 contaminants including benzo(a)pyrene, pentachlorophenol, toluene and selected metals (EA, 2008). The SSVs are conservative and are to be used for screening to provide an early indication of the potential for risks to exist. Concentrations of contaminants exceeding the SSVs may indicate a concern, which may warrant further investigation or risk evaluation.
However, the following contaminants were identified at levels that may present a risk to human health:
·dioxins and furans; and

It is becoming clear from the results and other studies that there are other contaminants
present in waste whose effects in soil environments have not been well studied and there remains significant uncertainty regarding the potential longer term impacts of these contaminants on the quality of the land bank, and the potential for bioaccumulation of more persistent organic contaminants within receiving soils, and potentially crops grown on the receiving soils.

...Particular concerns revolve around the role of anti-microbial chemicals and the effect which these could have on naturally occurring soil bacteria and fauna intrinsic in maintaining healthy soil conditions.

...While the presence and behaviour of nutrients (particularly nitrate) and more established
contaminants such as heavy metals in controlled waters are well understood, there is little information regarding the current levels, risks and impacts from emerging toxics and other organic pollutants which could be present in wastes being spread to land and ultimately end up in surface water, groundwater and the marine environment.

... but perhaps the biggest risk to the landbank is from the spreading and incorporation
of physical contaminants into agricultural soils (for example plastics, microplastics)
Coupled with advances in pharmaceutical and healthcare industries, there is an ongoing shift away from the more well understood traditional contaminants (i.e. heavy metals) to an ever increasing list of new chemicals, whose behaviour in the environment is not well understood.

In addition to the emerging toxics (including phthalates, antimicrobials, personal care products) there is also evidence of many persistent organic pollutants

As our understanding of the behaviour and longevity of some contaminants in the natural environment has improved (and continues to do so), the number of potential contaminants present in wastes and soils, which may pose a risk to human health and the wider environment, has expanded. Our knowledge is continually evolving and currently includes the following as a non-exhaustive list: PAHs, PCBs, dioxins and furans, Per- and Polyfluoroalkylated Substances (PFAS e.g. PFOS and PFOA), PDBEs, phthalates,
antibiotics, human and veterinary medicines, pesticides, and antimicrobial chemicals.
In addition to chemical constituents of waste, there are also concerns over physical contaminants particularly with regard to plastics and microplastics. The latter are of particular concern due to their small size, ability to be retained by WwTW (Carr et al., 2016), and ability to potentially sequester other contaminants (e.g. PCBs, dioxins, DDTs and PAHs) which are subsequently released as the plastics break down in soils (Nizetto at al., 2016).

The fate and behaviour of many of these compounds in the soil environment are only beginning to be investigated, and the risks associated with these contaminants is not yet understood. Current testing suites for characterising wastes and soils remain largely unchanged, despite increasing evidence of the identification of low levels of contaminants in waste streams.

There are uncertainties over the levels of these contaminants present in wastes spread to land. Specifically, there is uncertainty over whether these contaminants pose a risk to human health and the wider environment, either at the levels present in wastes or through enrichment in soils due to repeated applications over successive years."

Saturday, 13 June 2020

Recent research on Microplastics & Sewage Sludge / Biosolids

Recent Publications on Microplastics and Sewage Sludge / Biosolids

1. "Long-term assessment of nanoplastic particle and microplastic fiber flux through a pilot wastewater treatment plant using metal-doped plastics" June/2020

"nanoplastics and microplastics were tracked through a wastewater treatment plant. Over 98% of plastic particles sequestered into biosolids."
"As the majority of particulate plastic is retained in the sludge, the burden of plastic pollution would shift with sewage sludge application to soil"
" the material that may enter the environment in those locations where sludge is still used as an amendment to agricultural soils."
( )

2. "Plastic Pollution in Soils: Governance Approaches to Foster Soil Health and Closed Nutrient Cycles " May/2020

"Plastic pollution in soils pose a major threat to soil health and soil fertility, to food security and human health. The highest source of microplastic input into the soil is the direct application of sewage sludge for agricultural fertilization …It is, therefore, to be welcomed—also because of other pollutants in sewage sludge—that in Germany, the direct soil related spreading of sewage sludge will be largely prohibited in the future by the respective command‐and‐control legislation"
 "the potentially high contamination of sewage sludge with a wide variety of pollutants and microplastic particles has already led to an increased focus on indirect, thermal sewage sludge recycling in Germany and the EU. The direct recovery of essential nutrients such as phosphorus from sewage sludge by specific (preferably energy‐efficient) recycling processes is, therefore, seen as future‐oriented. This would also lead to reduced plastic pollution of agricultural soils"

3. "High microplastic levels in soil can halve worm fertility" Oct/2019

“Given we know that microplastics are accumulating in our soils and can stay there for a very long time, we clearly need to understand the effect they are having on our soil ecosystems and the long-term risks they may pose.”
( )

4. "Municipal sewage sludge as a source of microplastics in the environment" April/2020

"Sewage sludge serves as a source of MPs to the environment, predominantly through the application of biosolids on agricultural lands ... land applied biosolids presents a dangerous opportunity
 for large amounts of Microplastics to enter the environment and accumulate up the food chain"
( )

5. "Microplastics and pollutants in biosolids have contaminated agricultural soils: An analytical study and a proposal to cease the use of biosolids in farmlands" April/2020

"This study examines the detrimental effects of the existing methods for recycling biosolids. Such methods produce negative consequences in terms of contaminating farmlands with microplastics,
micropollutants, chemicals and pathogens. In addition the negative effects of stockpiling biosolids is likewise be examined."
"The agricultural applications of biosolids produce known biological and health concerns, and contamination of farmland through the accumulation of different types of pollutants is occurring despite governing authorities implementing restrictions to lessen their environmental burden."
"Furthermore emerging pollutants, such as microplastics, nanoplastics, pharmaceutical and industrial chemicals, are leading to further contamination of agricultural soils."
"... although guidelines address known pollutants and place ceiling concentrations upon them in order to mitigate their consequences, emerging pollutants, such as pharmaceuticals and chemicals used in the production of household items, have no such limits placed upon them. Thus they are uninhibited from accumulating in the soils on which they are applied."
"Environmental impact of biosolids stockpiles - while stockpiles remain untouched, they contribute to the wastewater treatment industry's damaging carbon footprint … they present a significant source of greenhouse gas emissions worldwide … and may also be responsible for polluting waterways, thus affecting the aquatic environment in addition to polluting the atmosphere."
( )

6. "More than 1,200 tonnes of microplastics are dumped into Aussie farmland every year from wastewater sludge" June/2020

"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"
( )

7. "Microplastic in soil–current status in Europe with special focus on method tests with Austrian samples" April/2020

"In wastewater treatment plants 90% of the microplastic–fibers of textiles, particles of cosmetic and hygiene products are transferred into sewage sludge and remains there independent from the treatment procedures"
( )

8. "Transfer and transport of microplastics from biosolids to agricultural soils and the wider environment" July/2020

"This study reinforces the hypothesis that biosolids are a significant source of MicroPlastics to agrosystems … long-term accumulation of MP fibers in soils on plant growth and soil biota could pose a risk to agricultural sustainability"

9. "Microplastics: from origin to impacts" March/2020

"The large proportion of MPs removed during wastewater treatment may be retained in sewage sludge. Depending on the treatment process applied at wastewater treatment plants and during subsequent treatment, the number of particles in sludge has been seen to vary. Following treatment, a large proportion of sludge becomes biosolids, transferred to terrestrial ecosystems through land application and also landfilling. This presents a further problem; in repurposing sludge, MPs are directly released to the terrestrial environment. Further research into the consequences of sludge application and terrestrial transfer and fate of MPs are urgently required"
"Sewage sludge has been identified as a point source for the release of MPs on land ... the presence of these particles in terrestrial ecosystems may facilitate the transport of organic contaminants in soil … If MPs persist and accumulate in soils, there may be significant direct impacts on agriculture and the functioning and biodiversity of terrestrial ecosystems"

10. "An Overlooked Entry Pathway of Microplastics into Agricultural Soils from Application of Sludge-Based Fertilizers" March/2020

"The quantity of Microplastics in soils exhibited a close correlation with application rate of sludge-based fertilizers... sludge composts may act as a vehicle of MPs into soils, enter soil biota and in turn influence the spread of MPs in the environment"
( )

11. "A scientific perspective on microplastics in nature and society" February/2020

"Plastic and other particulate matter are removed from the liquid waste stream via sedimentation and end up in sewage sludge. Because sewage sludge is used as a fertilizer, microplastics can thereafter be spread on agricultural lands and thus re-emitted to terrestrial ecosystems"
"Transport of plastic particles to air derived from dried sewage sludge onto agricultural soils has also been postulated, supported by the finding that synthetic clothing fibres persisted in soils up to 15 years after being applied"
( )

12. "Microplastics making their way to British farms in human sewage fertiliser" Feb/2020

"It warns microplastics could harm soil ecosystems or crops either directly or through hormone-disrupting substances, and contain chemicals that could be released slowly as they break down over hundreds of years"
( )

13. Government of Canada - "Draft science assessment of plastic pollution"  Jan/2020 - 

"It is estimated that 99% of microplastics are removed from the influent but are retained in sewage sludge ... Microplastics can therefore enter terrestrial environments through the application and use of sewage sludge as fertilizers for agriculture or landscaping purposes"
( )

14. "Mapping microplastics in sludge" April/2018

" it was estimated that over 500 billion microplastics are released into the environment via sewage sludge application each year, to agricultural soils, green areas and soil producers. This likely represents a significant source of microplastics to terrestrial and marine systems."
( )

Microbiologist, Dr. Richard Honour - 

Plastics in Sewage Sludge
Researchers have also looked into how polyester microfibers may be affecting microorganisms in the soil, especially since sewage sludge is loaded with microfibers. They found that the microplastics did, indeed, lead to changes in the soil, including altering the bulk density, water-holding capacity and microbial activity.
Writing in the journal Environmental Science & Technology, researchers noted that wastewater treatment plants act as receptors for the "cumulative loading of microplastics." The solids and liquids are separated using a settlement process, which results in the majority of microplastics (MP) ending up in sewage sludge.
Different methods of treatment affected the end number of particles found in the sludge, but the study found microplastic amounts ranging from 4,196 to 15,385 particles kg–1 (dry weight) in sludge samples.
The researchers noted, "This study highlights the potential for sewage sludge treatment processes to affect the risk of MP pollution prior to land spreading and may have implications for legislation governing the application of biosolids to agricultural land."
Microplastics may act like sponges for contaminants including heavy metals, persistent organic pollutants, polychlorinated biphenyls (PCBs) or pathogens, for instance, and may cause harm on a cellular or subcellular level,  raising serious questions about the risks of exposing soil to them.
Indeed, wastewater treatment plants are efficient at removing microplastics from sewage, but they become trapped in the sludge. This helps keep them out of waterways, unless they're applied to agricultural soils (which may run off into waterways).
When researchers evaluated 31 fields that had applications of sewage sludge, microplastics were found in the samples at levels ranging from 18 to 41 particles g−1, with a median of 34 particles g−1.16 What's more, the microplastic levels increased on fields with higher rates of sludge applications.
"Our results indicate that microplastic counts increase over time where successive sludge applications are performed," the researchers adding, "Sludge is proposed as a primal driver of soil microplastic pollution."


Update for June 24th

Source, occurrence, migration and potential environmental risk of microplastics in sewage sludge and during sludge amendment to soil”

“Microplastics can adsorb heavy metals, organic pollutants, antibiotics and ARGs, and the mechanism of adsorption mainly relies on physical interaction. MPs that are aged by UV irradiation and weathering will adsorb more pollutants because of the increased specific surface area and oxygen-containing surface groups. Soil amendment with sludge is an important pathway of sludge recycling, but the MPs input with the sludge amendment will accumulate in the soil. The MPs will influence the physicochemical properties of soil such as soluble substance concentration, bulk density and hydrodynamics, and may accumulate in plants. The combination of MPs and the pollutants they adsorb might increase the risk of soil pollution. The desorption and migration of pollutants orginally adsorbed by MPs make them become vectors to transfer pollutants, which increases the risks of spreading heavy metals, organic pollutants, antibiotics and ARGs in soils”

Update for June 25

""Most research has so far focused on agricultural systems, which are expected to contain the largest amount of microplastics because of input pathways including sewage sludge""

Update for June 30th

Our fruits and veggies are sucking up microplastics through their roots

"new research has shown that microplastics can penetrate the roots of crops, traveling up the plant into the parts we eat"


Micro- and nano-plastics in edible fruit and vegetables. The first diet risks assessment for the general population

"Agricultural systems are the final recipients of a number of several pollutants and nanomaterials, including microplastics (MPs), with effects relatively unknown. The general lack of understanding regarding nanomaterial fate and effects in agricultural systems is troublesome given the potential for food chain contamination and for an uncharacterized pathway of human exposure"
"Micro- and nano-plastics in edible fruit and vegetables. The first diet risks assessment for the general population"


Update for August 8th

Microplastics in soils: a review of possible sources, analytical methods and ecological impacts

"The annual amount of MPs that enter soils through the use of sewage sludge on arable lands is larger than that released into the oceans. Furthermore, sewage sludge discharged into agricultural soils is estimated to be one of the largest sources of MPs entering the environment. Applying sewage sludge as a fertilizer to the soil environment leads to pollution by synthetic fibers, which are mobile and persistent."

From the article ... "Microplastics as vectors for pollutants and additives in soils" 

“after plastics enter the soil environment, they release toxic plastic additives (plasticizers, retardants, antioxidants and photostabilizers), which threaten ecosyste
ms and impact long‐term soil quality. Furthermore, the weathered surfaces of MPs can act as high‐capacity carriers by adhering microorganisms (pathogens) and other toxic pollutants (organic contaminants, heavy metals, pesticides, etc.) in the soil to them. Under certain conditions, the slow degradation process of plastics can release these adsorbed toxic chemicals back to the surrounding environment. Moreover, soil organisms can have access to high concentrations of MPs via ingestion; hence MPs are transported to the food chain and act as potential vectors that may carry pathogens and contaminants in soil systems. Therefore MPs, which act as vectors for these chemicals, move along with soil particles and not only threaten the aquatic environment but also the soil environment”


Update for August 17th

"Microplastics, especially polyethylene with high adsorption and desorption potentials may serve as a source and carrier to triclosan, and its amendment can change triclosan's environmental behavior and further risk in soil."

Update for August 26

Microplastics removal in wastewater treatment plants: a critical review

"reported that successive sludge application on agricultural fields resulted in microplastic accumulation over time. Microplastic content in sludge of the agricultural fields ranged from 18 000 to 41 000 particle per kg. It is expected that microplastics in soil enter the aquatic environment through surface runoff, irrigation or wind"
"The majority of plastics removed during sewage treatment are retained in sewage sludge ... Large numbers of plastic particles enter the terrestrial environment where sludge is reused for agriculture. More research is needed on the environmental fate and impact of plastics in sludge-amended soils, in particular where agricultural reuse of sewage sludge is common practice"


August 26th

Microplastics in Sewage Sludge -
Dr. Scott Coffin - "over time our agricultural soils may become toxic with the addition of these biosolids"
Microplastics in Sludge -starts around the 34 minute mark.

August 26th

Environmental fate and impacts of microplastics in soil ecosystems: Progress and perspective

 "we assessed the ecotoxicological consequences of microplastics contamination on soil ecosystems, including the effects on soil physiochemical properties, terrestrial plants, soil fauna, and soil microbes"


Are Agricultural Soils Dumps for Microplastics of Urban Origin?

"Based on new Microplastic emission estimates in industrialized countries, we suggest that widespread application of sewage sludge from municipal wastewater treatment plants (WWTPs) to farmlands is likely to represent a major input of MPs to agricultural soils, with unknown consequences for sustainability and food security."
" We expect that none of the common processing steps (e.g., drying, pasteurization, composting, etc.) to produce biosolids from WWTP sludge for agricultural use will remove the MP load."
"Reports are emerging about the occurrence and impacts of MPs in soil, both from breakdown of plastics and sludge additions. Reproduction of worms was recently shown to be impacted at MP exposure levels possibly representative of those in agricultural soils receiving sewage sludge application"
"MPs can potentially impact soil ecosystems, crops and livestock either directly or through the toxic and endocrine-disrupting substances added during plastics manufacturing."
"Studies assessing the scale of contamination of agricultural soils by MPs are notable for their absence while farm soils may arguably represent one of their largest environmental reservoirs."


Update September 2nd

Microplastic pollution devastating soil species, study finds

“We call for a reduction in the use of plastics and to avoid burying plastic wastes in soils, as this may bring adverse ecological consequences on soil communities and biogeochemical cycling in terrestrial ecosystems.”


Microplastics in farm soils: A growing concern

"Microplastics arrive on farms through processed sewage sludge used for fertilizer ... alarming potential impacts of this contamination on all aspects of agricultural systems from soil quality to human health"


Update - Sept. 8th

Inhibitory effect of microplastics on soil extracellular enzymatic activities by changing soil properties and direct adsorption

"Microplastics (MPs), as a new type of environmental pollutant, pose a serious threat to soil ecosystems ... MPs competed with soil microorganisms for physicochemical niches to reduce microbial activity and eventually, extracellular enzyme activity"