Article

A comparison of five pesticides adsorption and desorption processes in thirteen contrasting field soils.

George E. Brown, Jr. Salinity Laboratory, USDA-ARS, 450 West Big Springs Road, Riverside, CA 92507-4617, USA.
Chemosphere (Impact Factor: 3.5). 12/2005; 61(5):668-76. DOI: 10.1016/j.chemosphere.2005.03.024
Source: PubMed

ABSTRACT Batch adsorption and desorption experiments were performed using thirteen agricultural soil samples and five pesticides. Experimental data indicated a gradient in pesticide adsorption on soil: trifluralin > 2,4-D > isoproturon> atrazine > bentazone. Atrazine, isoproturon and trifluralin adsorption were correlated to soil organic matter content (r2 = 0.7, 0.82, 0.79 respectively). Conversely, bentazone adsorption was governed by soil pH (r2 = 0.68) while insignificant effect has been shown in the case of 2,4-D. Multiple linear regressions were used to combine relationships between the various soil parameters and the Freundlich adsorption coefficient (K(f)) of each pesticide. Then desorption was assessed since it may reflect some of the interactions involved between the pesticides and the soil components. Adsorbed molecules were released into aqueous solution in the following order: bentazone > atrazine> isoproturon> 2,4-D > trifluralin. The occurrence of hysteresis did not allow an accurate interpretation of the pesticide desorption data because of the possible interplay of several processes.

2 Bookmarks
 · 
311 Views
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Carbamates neurotoxins are a group of compounds acting as pseudo-irreversible inhibitors of an enzyme acetylcholinesterase and butyrylcholinesterase. The compounds are well known as pesticides. Some of them, such as rivastigmine, pyridostigmine, and neostigmine, can be used as drugs for Myasthenia gravis or Alzheimer disease as well. The present review is aimed to summarize the basic facts about carbamate pesticides. Legislative aspects, e.g. law No. 326/2004 Coll., in the Czech Republic and examples of accidental exposures to carbamates in the country are provided, too. Other general provisions are determined by the EU, in particular by the Directive 91/414/EHS. The European legislative is discussed, too. Finally, examples of accidental exposures are introduced in the study.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pesticide sorption on to the soil has a significant role in deciding the fate and behavior of pesticides in soil and aquatic environment. The present study investigates the adsorption of monocrotophos (MCP) and dichlorvos (DDVP) on the three soils of Malwa region of Punjab, India under different conditions. Batch adsorption experiments were preformed in replicates using 2 g of air-dried soil and varying concentrations of pesticides and 20 mL of 0.01 M CaCl2 as background electrolyte. The results revealed high adsorption of MCP and DDVP in soil B with kf-values 0.1261 and 0.0498 and n-values 2.7345 and 1.831, respectively. The adsorption isotherms obtained were analyzed and the data was subjected to classical Langmuir, Freundlich, and Temkin models. The experimental data best fitted to the logarithm form of Freundlich and Temkin model. Kinetics analyses were performed using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The regression results showed that the experimental data fitted very well with the pseudo-second order kinetic model as correlation coefficient value is very closer to 1 and also followed the intraparticle diffusion model, whereas, diffusion is not only the rate controlling step. The percentages desorption with tap and distilled water is 32–64% for MCP and 25–48% for DDVP.
    CLEAN - Soil Air Water 12/2011; 39(12). · 2.05 Impact Factor

Full-text (2 Sources)

Download
25 Downloads
Available from
Sep 17, 2014