Effect of addition of HPBCD on diuron adsorption–desorption, transport and mineralization in soils with different properties

Abstract

The influence of different soil properties on diuron adsorption, and the effect of hydroxypropyl-β-Cyclodextrin (HPBCD) on its desorption, leaching and mineralisation have been investigated. The significant variables on adsorption were organic matter (OM) content, aluminum oxides and clay fraction. Diuron desorption from soils presents negative hysteresis when HPBCD solutions were used as an extractant, in comparison to the positive hysteresis when using Ca(NO 3) 2 solutions. Therefore, higher amounts of Diuron were desorbed by HPBCD due to the formation of an inclusion complex that causes an increase in its solubility. However, the application of HPBCD in columns of selected soils did not cause increased leaching of the herbicide. Finally, the presence of HPBCD shows clearly an increase in the rate of mineralisation of diuron in contaminated soils and a drastic reduction of DT 50 values due to its increasing bioavailability. HPBCD is proposed as an efficient tool for Diuron soil bioremediation.

Behaviour of glyphosate in a reservoir and the surrounding agricultural soils

“…For a specific pesticide, when hydrophobic bonds are the only factor responsible for its adsorption, the K foc values should be relatively constant among the different soils. However, the values obtained in this study are quite different (Table 3), ranged from 7332 to 14263, indicating that the adsorption mechanism is related to some other soil properties in addition to the OC content (Morillo et al, 2002;Undabeytia et al, 2011;Rubio-Bellido et al, 2016). Morillo et al (2000) observed that GPS adsorption to three soils of different characteristics was not related to their CEC and clay mineral content, but to levels of iron and aluminium amorphous oxides and organic matter.…”

Bioaugmentation of PAH-Contaminated Soils With Novel Specific Degrader Strains Isolated From a Contaminated Industrial Site. Effect of Hydroxypropyl-β-Cyclodextrin as PAH Bioavailability Enhancer

“…HPBCD addition (Figure 5B) provoked a significant decrease of 25 days in the acclimation period (from 79 days for TME to 54 days for TME + HPBCD) (Table 6) in relation to the mineralization in the absence of HPBCD, although a similar global extension of mineralization and mineralization rate was determined (33.9 and 1.00% day –1 , respectively). The explanation for this reduction is the higher bioaccessibility of PYR after HPBCD application due to an increase of its bioavailable fraction just from the beginning of the assay (Reid et al, 2000), reaching a similar global extension of mineralization corresponding to the global PYR bioavailable fraction in soil (Rubio-Bellido et al, 2016). These results also reveal that the increase of PYR bioavailability due to HPBCD addition has no toxic effects on the indigenous microbiota.…”

Sorptive Interactions Evaluation of Benomyl Metabolites Mecarzole with the Varyingly Selected Minerals

“…Major portion of the pesticides reaches the nontarget regions in the ecological setting either through spray drifting, run off and percolation (Singh and Cameotra, 2013). Pesticides' adsorptive and persistence characteristics often determine their distribution in the environmental compartments (Yue et al, 2017;Rubio-Bellido et al, 2016). Soils have been characterized with severe pollution problems especially due to agrochemicals use in the agricultural regions.…”