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Environ Sci Pollut Res Int. 2014;21(16):9453-60. doi: 10.1007/s11356-013-2103-1. Epub 2013 Sep 14.

Biodegradability of a polyacrylate superabsorbent in agricultural soil.

Author information

1
Institute for Landscape Ecology and Resources Management (ILR), Justus Liebig University, Giessen, Germany, burkhard.wilske@umwelt.uni-giessen.de.

Abstract

Superabsorbent polymers (SAP) are used, inter alia, as soil amendment to increase the water holding capacity of soils. Biodegradability of soil conditioners has become a desired key characteristic to protect soil and groundwater resources. The present study characterized the biodegradability of one acrylate based SAP in four agricultural soils and at three temperatures. Mineralisation was measured as the (13)CO₂ efflux from (13)C-labelled SAP in soil incubations. The SAP was either single-labelled in the carboxyl C-atom or triple-labelled including additionally the two C-atoms interlinked in the SAP backbone. The dual labelling allowed estimating the degradation of the polyacrylate main chain. The (13)CO₂ efflux from samples was measured using an automated system including wavelength-scanned cavity ring-down spectroscopy. Based on single-labelled SAP, the mean degradation after 24 weeks varied between 0.45% in loamy sand and 0.82% in loam. However, the differences between degradation rates in different soils were not significant due to a large intra-replicate variability. Similarly, mean degradation did not differ significantly between effective temperature regimes of 20° and 30 °C after 12 weeks. Results from the triple-labelled SAP were lower as compared to their single-labelled variant. Detailed results suggest that the polyacrylate main chain degraded in the soils, if at all, at rates of 0.12-0.24 % per 6 months.

PMID:
24037296
DOI:
10.1007/s11356-013-2103-1
[Indexed for MEDLINE]

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