Dissolved organic carbon interactions with sorption and leaching of diuron in organic‐amended soils

Abstract

Diuron (N¢-[3,4-dichlorophenyl]-N,N-dimethylurea) is one of the most frequently used herbicides in olive groves in Spain and other Mediterranean countries. The main objective of this work was to investigate the effect of the dissolved organic carbon (DOC) from a commercial humic amendment, derived by composting the liquid waste of the olive-mill process (LF), and a solid residue from the olive oil production industry (AL) on the sorption and leaching behaviour of diuron in soil. For this purpose, a clay and a sandy soil were selected. Soil sorption coefficients of diuron increased with LF (32%) and AL (76%) amendment in the sandy soil, whereas sorption decreased in the clay soil upon amendment, especially in the case of the liquid LF (52%). The DOC from LF and AL is composed of very poorly humified molecules, which are strongly sorbed onto the clay soil and thus compete with diuron for the same sorption sites. Dialysis experiments revealed that diuron forms stable complexes with DOC from LF and AL. Leaching of diuron in columns of the sandy soil treated with the organic amendments caused earlier breakthrough and maximum concentration peaks at fewer pore volumes when compared with leaching with 0.01 M CaCl 2 . Competition between diuron and DOC molecules for sorption sites and diuron-DOC interactions can both account for the enhanced leaching of diuron.

Sorption of pharmaceuticals and personal care products to polyethylene debris

“…Firstly, organic pollutants can interact with DOM via hydrophobic interaction or complexation (Ilani et al 2005;Nelson et al 2000). Secondly, DOM can compete with organic pollutants for the sorption sites on the sorbent (Cox et al 2007). Additionally, DOM can be adsorbed to the sorbent first and then interact with the sorbate (Ling et al 2006;Sun et al 2008).…”

Direct and residual effects on diuron behaviour and persistence following two-phase olive mill waste addition to soil: Field and laboratory experiments

“…Several studies have demonstrated the beneficial effects of TPOMW in restoring crop productivity in degraded soils (López-Piñeiro et al, 2006, but very few studies have investigated diuron's behaviour in fresh TPOMW-amended soils Cox et al, 2007), and even fewer have been carried out in situ under field conditions, due to the high cost and difficulty (Cabrera et al, 2008a(Cabrera et al, ,b, 2009). In addition, to the best of our knowledge, there is no information on the influence of TPOMW organic matter transformation on diuron's fate in soils following repeated applications of this waste also under field conditions, although such information would be useful from the environmental perspective of the management of this herbicide in soils receiving this waste.…”

Validation of a liquid chromatography ultraviolet method for determination of herbicide diuron and its metabolites in soil samples

“…According to Tixier et al (2001), diuron can undergo transformations forming by-products with even greater toxicity. Its degradation in environment mainly occurs through microorganism biological activity, producing three primary metabolites: 3,4-dichlorophenylurea (DCPU), 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU), and 3,4-dichloroaniline (DCA) (Dalton et al 1996, Cox et al 2007). These by-products can persist longer in aquatic and terrestrial ecosystems due to its great stability (Tixier et al 2000, Sorensen et al 2003.…”