0
Article Tier 2 Environmental Sources Sign in to save

Polyethylene and poly (butyleneadipate-co-terephthalate)-based biodegradable microplastics modulate the bioavailability and speciation of Cd and As in soil: Insights into transformation mechanisms

Journal of Hazardous Materials 2022 53 citations

AI summary Read the abstract

Biodegradable PBAT and conventional polyethylene microplastics added to soil were both found to alter soil physicochemical properties and change the speciation and bioavailability of heavy metals including lead and cadmium. The study highlights that both conventional and so-called biodegradable microplastics can exacerbate heavy metal risks in contaminated agricultural soils.

Polymers

Microplastics (MPs) that enter the soil can alter the physicochemical and biochemical properties of soil and affect speciation of heavy metals (HMs), thereby perturbing the bioavailability of HMs. However, the mechanisms underlying these effects are not understood. Therefore, we investigated the effects of MPs from poly (butyleneadipate-co-terephthalate)-based biodegradable mulch (BM) and polyethylene mulch (PM) in Cd- or As-contaminated soil on soil properties and speciation of HMs. MPs were characterised using Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The addition of MPs reduced the bioavailability of HMs in soil and promoted the transformation of HMs into inert fractions. The mechanisms underlying the reduction of the bioavailability of HMs in soils could be as follows: (1) the entry of MPs into the soil changed its properties, which reduced the bioavailability of HMs; (2) FTIR and XPS analyses revealed that the hydroxyl and carboxyl groups and benzene ring present on the surface of aged MPs stabilized complexes (As(V)-O) with As(V) may have directly reduced the bioavailability of As(V) in soil; (3) aged BM exposed more amounts and types of reactive functional groups and was more effective in stabilising soil HMs than PM. Overall, this study provides new insights regarding the complexation mechanisms of soil HMs by MPs from different plastic mulch sources.

More Papers Like This

Article Tier 2

Influence of polyethylene-microplastic on environmental behaviors of metals in soil

AI summary Read the abstract

Researchers investigated how polyethylene microplastics affect the adsorption, desorption, and bioavailability of heavy metals in soil. They found that adding microplastics altered how metals bind to soil particles and increased the mobility of certain metals like cadmium and lead. The study suggests that microplastic contamination in soils may change the environmental behavior of heavy metals, potentially increasing their availability to plants and soil organisms.

Article Tier 2

Microplastics can affect soil properties and chemical speciation of metals in yellow-brown soil

AI summary Read the abstract

Researchers added five polymer types (LLDPE, PA, PU, PS, LDPE) at various concentrations to yellow-brown soil and measured their effects on soil physicochemical properties and the speciation of cadmium, copper, lead, and zinc. MPs shifted heavy metal distribution toward more bioavailable fractions, suggesting that microplastic contamination can increase the extractability and potential toxicity of co-occurring metals in soil.

Meta Analysis Tier 1

Contrasting impacts of biodegradable and conventional microplastics on heavy metal bioavailability in soils: A multilevel meta-analysis

AI summary Read the abstract

"Biodegradable" plastics are often marketed as the eco-friendly alternative to regular plastic, but this study found they may actually make soil pollution worse: they caused toxic heavy metals like cadmium already lurking in soil to become more available for uptake by plants, by changing soil chemistry and microbial life. This matters because metals absorbed by crops can end up in our food, so switching to biodegradable plastics isn't automatically the safer choice, it may trade one environmental problem for another.

Article Tier 2

The Hidden Crisisof Biodegradable Plastics: PolylacticAcid Microplastics Increase Soil Cd and Pb Bioavailability and AssociatedHuman Health Risks

AI summary Read the abstract

Researchers conducted a pot experiment to assess how polylactic acid (PLA) microplastics affect the soil availability and plant uptake of cadmium and lead in co-contaminated agricultural soils. PLA microplastics increased the bioavailability of both heavy metals, raising human health risks from crops grown in PLA-contaminated soils.

Article Tier 2

Effect of biodegradable microplastics and Cd co-pollution on Cd bioavailability and plastisphere in soil-plant system

AI summary Read the abstract

Researchers examined how biodegradable microplastics interact with cadmium contamination in agricultural soil where lettuce is grown. They found that the biodegradable plastics indirectly increased cadmium availability to plants by lowering soil pH and changing soil chemistry. The study suggests that even eco-friendly biodegradable plastics may worsen heavy metal contamination risks in farming soils.

Research digests by email

When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.

Email me about

Share this paper