We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Pollution of agricultural soils by microplastics and their interaction with residual herbicides
Summary
Researchers investigated how microplastics interact with three residual herbicides -- diuron, hexazinone, and S-metolachlor -- in agricultural soil matrices, using near-infrared spectroscopy, multispectral analysis, and HPLC to assess sorption and desorption isotherms and evaluate the most effective detection methods for MPs at varying concentrations.
Agricultural soils contaminated by microplastics (MPs) pose a significant con-cern regarding the efficacy of residual herbicides in controlling weeds. An im-portant part of this study was investigating how MPs interact with three residual herbicides: diuron, hexazinone, and S-metolachlor. The main focus was on identifying the most effective analytical methods for detecting MPs in soil matri-ces and assessing the sorption and desorption behavior of the herbicides. Near-infrared spectroscopy (NIR) and multispectral analysis were used, demonstrating high sensitivity in detecting MPs at various concentrations. High-performance liquid chromatography (HPLC) was used to assess the interaction between MPs and herbicides, enabling the determination of sorption and de-sorption isotherms. MPs were only detected at high concentrations (20%) using X-ray analysis. NIR at 2,300 nm and multispectral analysis at 395 nm showed greater accuracy and sensitivity in distinguishing between all levels of MPs. Scanning Electron Microscopy (SEM) revealed that MPs possess an amor-phous structure, distinct from crystalline soil, which may influence their interactions with other soil constituents. Regarding the interaction of MPs with herbicides, the presence of MPs influenced the sorption of S-metolachlor in the soil, resulting in up to a 10% increase in the amount of the herbicide sorbed, with a sorption coefficient (Kd) of 4.85 L kg-¹ with the addition of 5% MPs. However, there was no return of S-metolachlor to the soil solution, as demonstrated by a hysteresis (H) of 0.99 for the treatment with 5% MPs, compared to a control treatment with an H of 0.88. Diuron and hexazinone showed little interaction with MPs; the sorbed percentage of diuron was around 40% in all treatments (amended and unamended soils), with a Kd ranging from 1.84 to 2.12 L kg-¹. In the case of hexazinone, the behavior was similar, but the sorbed percentage was around 20% for all treatments (amended and unamended soils), with a Kd ranging from 1.63 to 2.03 L kg-¹. Only small amounts of both herbicides were taken up by plants. In all treatments (amended and unamended soils), approx-imately 15% of hexazinone and diuron was taken up. These interactions signifi-cantly impact herbicide efficacy in weed control and increase the risk of envi-ronmental contamination. Identifying these polymers and understanding the interaction of residual herbicides with MPs in agricultural soils is crucial for developing management strategies that consider the presence of MPs, thereby promoting more sustainable agricultural practices. Keywords: Residues plastic. Contamination. Analytical techniques. Sorption. Desorption
Sign in to start a discussion.
More Papers Like This
How does soil contamination by microplastics interferes the sorption and desorption processes of three herbicides?
Researchers tested how varying proportions of polyethylene microplastics (0-100% by weight) affected the sorption and desorption of three herbicides (hexazinone, diuron, S-metolachlor) in soil. Microplastic presence significantly altered sorption behavior for S-metolachlor, with effects depending on microplastic concentration and herbicide chemical structure.
Adsorption-desorption of propyrisulfuron in six typical agricultural soils of China: Kinetics, thermodynamics, influence of 38 environmental factors and its mechanisms
This study investigated how the common herbicide propyrisulfuron behaves in six different Chinese agricultural soils, and notably found that microplastic contamination in the soil was one of 38 environmental factors influencing how much of the herbicide was adsorbed. The herbicide bound tightly enough to soil particles that residues could persist and potentially leach into groundwater with continued use. The incidental finding about microplastic influence on herbicide adsorption points to a broader issue: microplastics in farmland soils may alter the behavior of pesticides and other agrochemicals, with implications for both crop safety and water quality.
Vis-NIR spectroscopy based rapid and non-destructive method to quantitate microplastics: An emerging contaminant in farm soil
Researchers developed a rapid, non-destructive method using visible and near-infrared spectroscopy to quantify microplastics in farm soil. The study suggests this approach could overcome the limitations of current extraction-based methods, which are time-consuming and prone to errors and biases.
Rapid detection of microplastics in plastic-covered soils using FT-NIR and ATR-FTIR spectral data fusion
Researchers developed a rapid, non-destructive method to detect microplastics in agricultural soils by combining two infrared spectroscopy techniques (FT-NIR and ATR-FTIR) with machine-learning models. The fused spectral approach substantially outperformed either technique alone, detecting microplastics down to around 7 parts per million. Fast, accurate soil screening tools are critical for understanding and managing the growing microplastic contamination in farmland.
Comparative analysis of the sorption behaviors and mechanisms of amide herbicides on biodegradable and nondegradable microplastics derived from agricultural plastic products
Sorption behavior of amide herbicides onto biodegradable and non-biodegradable microplastics was compared, finding that polymer type and weathering state significantly influenced herbicide uptake. The results inform assessments of whether microplastics in intensively farmed soils amplify herbicide mobility and bioavailability.