0
Article Tier 2 Environmental Sources Remediation Sign in to save

Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

Frontiers of Environmental Science & Engineering 2021 29 citations

AI summary Read the abstract

Researchers found that polypropylene microplastics reduce soil's ability to bind the toxic heavy metal cadmium, with the effect varying by soil composition and microplastic aging — suggesting that microplastic contamination could indirectly increase the risk of heavy metals leaching into groundwater.

Polymers

Microplastics (MPs) are widely present in a variety of environmental media and have attracted more and more attention worldwide. However, the effect of MPs on the interaction between heavy metals and soil, especially in soil solid fraction level, is not well understood. In this study, batch experiments were performed to investigate the adsorption characteristics of Cd in bulk soil and three soil solid fractions (i.e. particulate organo matter (POM), organic-mineral compounds (OMC), and mineral) with or without polypropylene (PP) MPs. The results showed that the addition of PP-MPs reduced the Cd adsorption capacity of the bulk soil in aqueous solution, and the effects varied with PP-MPs dose and aging degree. Whereas, the responses of the three fractions to PP-MPs were different. In presence of PP-MPs, the POM and OMC fractions showed negative adsorption effects, while the mineral fraction showed positive adsorption. For the bulk soil, POM and OMC fractions, the adsorption isotherm fitted to the Langmuir model better than the Freundlich model, whereas, the Freundlich isotherm model was more fitted for the mineral fraction. Combined with the comprehensive analysis of the partitioning coefficients, XRD and FTIR results, it was found that OMC fraction extremely likely play a leading role in the bulk soil adsorption of Cd in this study. Overall, the effect of MPs on adsorption capacity of the bulk soil for Cd may be determined by the proportion of POM, OMC, and mineral fractions in the soil, but further confirmation is needed.

More Papers Like This

Article Tier 2

Relevance of dissolved organic matter components on the adsorption behaviors of cadmium onto non-biodegradable and biodegradable microplastics in an agricultural soil

AI summary Read the abstract

Researchers found that microplastics in agricultural soil — both conventional and biodegradable types — reduce the soil's ability to bind cadmium, a toxic heavy metal, largely by altering organic matter that controls metal mobility. This suggests microplastic contamination could increase cadmium availability in farmland, raising potential food safety concerns.

Article Tier 2

Enhanced Adsorption of Cadmium onto Microplastics Derived from Polyethylene Mulching Film by Weathering

AI summary Read the abstract

Weathered polyethylene microplastics from agricultural mulch film showed more than four times greater adsorption capacity for cadmium ions compared to pristine particles, driven by increased surface roughness and oxygen-containing functional groups that develop during environmental aging. Because weathered microplastics are far more common in real environments than pristine particles, this finding significantly elevates the estimated risk of microplastics acting as vectors for heavy metal transport in contaminated soils and water.

Article Tier 2

Polyethylene Microplastics Modulate the Copper Adsorption–desorption Processes in Agricultural Soils

AI summary Read the abstract

Batch adsorption experiments showed that adding 1% polyethylene microplastics to two agricultural soils modestly increased copper adsorption capacity while altering desorption behavior in soil-type-dependent ways. This matters because microplastic accumulation in farmland can disrupt heavy metal cycling, potentially increasing bioavailability of toxic metals like copper in crops and the humans and animals that consume them.

Article Tier 2

Effect of Microplastics on the Adsorption and Desorption Properties of Cadmium in Soil

AI summary Read the abstract

Polyethylene and polypropylene microplastics were found to reduce soil's capacity to adsorb cadmium, a toxic heavy metal, raising concerns that microplastic contamination in farmland soils could increase the mobility and risk of heavy metal pollutants.

Article Tier 2

A potential threat from biodegradable microplastics: mechanism of cadmium adsorption and desorption in the simulated gastrointestinal environment

AI summary Read the abstract

Laboratory experiments found that biodegradable polylactic acid (PLA) microplastics adsorb significant amounts of cadmium, and simulated gastrointestinal digestion dramatically increased cadmium bioaccessibility — 19% released in the gastric phase and 62% in the intestinal phase — far exceeding conventional PP and PA microplastics. This indicates that biodegradable plastics marketed as environmentally safer alternatives may pose heightened risks as heavy metal vectors in the human gut, challenging assumptions about their safety.

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