The pesticide chlordecone is trapped in the tortuous mesoporosity of allophane clays

Woignier, Thierry; Clostre, Florence; Fernandes, Paula; Soler, Alain; Rangon, Luc; Sastre-Conde, Maria Isabel; Jannoyer, Magalie

doi:10.1007/s11356-017-9370-1

Cited by 8 publications

(3 citation statements)

References 94 publications

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“…Formation of SROAS is not limited to volcanic parent material, but also takes place along pedogenetic transformation of more crystalline siliceous rocks 8 – 10 . The presence of SROAS imposes peculiar properties on soil material with respect to retention of plant nutrients 11 , pollutants 12 and degradation products of soil organic matter (SOM) 13 , which promotes carbon sequestration in andic soils 14 . Efficient sorption of various compounds is ascribed to large surface areas and the microporous nature of SROAS, including the presence of reactive functional groups 15 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of short-range ordered aluminosilicates at ambient conditions

Lenhardt

Breitzke

Buntkowsky

et al. 2021

Sci Rep

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We report here on structure-related aggregation effects of short-range ordered aluminosilicates (SROAS) that have to be considered in the development of synthesis protocols and may be relevant for the properties of SROAS in the environment. We synthesized SROAS of variable composition by neutralizing aqueous aluminium chloride with sodium orthosilicate at ambient temperature and pressure. We determined elemental composition, visualized morphology by microscopic techniques, and resolved mineral structure by solid-state 29Si and 27Al nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Nitrogen sorption revealed substantial surface loss of Al-rich SROAS that resembled proto-imogolite formed in soils and sediments due to aggregation upon freezing. The effect was less pronounced in Si-rich SROAS, indicating a structure-dependent effect on spatial arrangement of mass at the submicron scale. Cryomilling efficiently fractured aggregates but did not change the magnitude of specific surface area. Since accessibility of surface functional groups is a prerequisite for sequestration of substances, elucidating physical and chemical processes of aggregation as a function of composition and crystallinity may improve our understanding of the reactivity of SROAS in the environment.

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Section: Introductionmentioning

confidence: 99%

Synthesis of short-range ordered aluminosilicates at ambient conditions

Lenhardt

Breitzke

Buntkowsky

et al. 2021

Sci Rep

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“…Similar to what has been shown in the USA, CLD has contaminated surface and ground water, and ineluctably through watershed hydrology, rain runoff and soil erosion [Bonan andPrime, 2001, Mottes et al, 2016], the molecule has reached marine environments [Bertrand et al, 2010]. However, a limited number of studies have specifically focused on the transport of CLD, especially between terrestrial and marine ecosystems [Woignier et al, 2018, Dromard et al, 2022. Currently, various coastal marine ecosystems, including mangroves, seagrass meadows and coral reefs, are known to be contaminated.…”

Section: A Brief Review Of Historical Contamination By Chlordeconementioning

confidence: 84%

Pesticide upsurge, cross-contamination and biodiversity: case studies from the Caribbean Coast Human-Environment Observatory

Hervé,

Sabatier,

Lambourdière

et al. 2023

Comptes Rendus. Géoscience

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Similar to many small islands within the Wider Caribbean Region, the French West Indies are rich but fragile island ecosystems threatened by global warming, pollutants and other anthropic pressures. To understand integrated and complex human impacts on the environment, the Caribbean Coast Human-Environment Observatory (OHM) is developing disciplinary and interdisciplinary studies related to the local-scale driving factors that affect the coastal evolution in Guadeloupe. We present here results that show the multiple causalities, causal asymmetries, and equifinality of environmental pollution related to chlordecone, glyphosate, arsenic and Sargassum and highlight the need to bring further knowledge and awareness to the local populations on these concerns.

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“…1). Table 2 lists the typical structural and porous features of allophane aggregates (Woignier et al 2017). The fractal dimension D (2.5-2.7) and tortuosity t (1.5-3.5) are dimensionless.…”

Section: Porous and Structural Features Of Allophane Aggregatesmentioning

confidence: 99%

Physical limitation of pesticides (chlordecone) decontamination in volcanic soils: fractal approach and numerical simulation

Woignier

Rangon

Clostre³

et al. 2019

Environ Sci Pollut Res

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In the French West Indies, the chlordecone (organochloride pesticide) pollution is now diffuse becoming new contamination source for crops and environment (water, trophic chain). Decontamination by bioremediation and chemical degradation are still under development but the physical limitations of these approaches are generally not taken into account. These physical limitations are related to the poor physical accessibility to the pesticides in soils because of the peculiar structural properties of the contaminated clays (pore volume, transport properties, permeability, and diffusion). Some volcanic soils (andosols), which represent the half of the contaminated soils in Martinique, contain nanoclay (allophane) with a unique structure and porous properties. Andosols are characterized by pore size distribution in the mesoporous range, a high specific surface area, a large pore volume, and a fractal structure. Our hypothesis is that the clay microstructure characteristics are crucial physico-chemical factors strongly limiting the remediation of the pesticide. Our results show that allophane microstructure (small pore size, hierarchical microstructure, and tortuosity) favors accumulation of chlordecone, in andosols. Moreover, the clay microporosity limits the accessibility of microorganisms and chemical species able to decontaminate because of poor transport properties (permeability and diffusion). We model the transport properties by two approaches: (1) we use a numerical model to simulate the structure of allophane aggregates. The algorithm is based on a cluster-cluster aggregation model. From the simulated data, we derived the pore volume, specific surface area, tortuosity, permeability, and diffusion. We show that transport properties strongly decrease because of the presence of allophane. (2) The fractal approach. We characterize the fractal features (size of the fractal aggregate, fractal dimension, tortuosity inside allophane aggregates) and we calculate that transport properties decrease of several order ranges inside the clay aggregates. These poor transport properties are important parameters to explain the poor accessibility to pollutants in volcanic soils and should be taken into account by future decontamination process. We conclude that for andosols, this inaccessibility could render inefficient some of the methods proposed in the literature.

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The pesticide chlordecone is trapped in the tortuous mesoporosity of allophane clays

Cited by 8 publications

References 94 publications

Synthesis of short-range ordered aluminosilicates at ambient conditions

Synthesis of short-range ordered aluminosilicates at ambient conditions

Pesticide upsurge, cross-contamination and biodiversity: case studies from the Caribbean Coast Human-Environment Observatory

Physical limitation of pesticides (chlordecone) decontamination in volcanic soils: fractal approach and numerical simulation

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