Modelling the photochemical generation kinetics of 2-methyl-4-chlorophenol, an intermediate of the herbicide MCPA (2-methyl-4-chlorophenoxyacetic acid) in surface waters

Authors

  • Elisa De Laurentiis Dipartimento di Chimica, Università di Torino, Via Pietro Giuria 5, Torino 10125, Italy
  • Marco Minella Dipartimento di Chimica, Università di Torino, Via Pietro Giuria 5, Torino 10125, Italy
  • Marco Bodrato MambaSoft, Via Barletta 90, 10136 Torino, Italy
  • Valter Maurino Dipartimento di Chimica, Università di Torino, Via Pietro Giuria 5, Torino 10125, Italy
  • Claudio Minero Dipartimento di Chimica, Università di Torino, Via Pietro Giuria 5, Torino 10125, Italy
  • Davide Vione Dipartimento di Chimica, Università di Torino, Via Pietro Giuria 5, Torino 10125, Italy

Keywords:

environmental photochemistry, sensitized transformation, chromophoric dissolved organic matter, photodegradation of contaminants, degradation by-products

Abstract

2-Methyl-4-chlorophenol (MCP) is the main transformation intermediate of the herbicide MCPA in surface waters and it is more toxic than its parent compound. MCP is produced from MCPA by both direct photolysis and •OH reaction. The latter process has higher yield of MCP from MCPA: 0.5 vs. 0.3 for the direct photolysis. Our model results show that the formation rate of MCP would be higher in waters that contain low organic matter and high nitrate and nitrite. Such conditions are favourable to MCPA direct photolysis and •OH-induced transformation, which are both inhibited by organic matter, while •OH formation is enhanced by nitrate and nitrite. Good agreement is obtained between model predictions and field data of MCPA transformation in the Rhône river delta (Southern France). The field data also suggest that MCP undergoes slightly faster transformation than MCPA in that environment.

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Published

2013-04-01

Issue

Vol. 16 No. 2 (2013): Celebrating the 20th Anniversary of the AEHMS: The Aquatic Ecosystem Puzzle

Section

Editorial

License

Manuscripts must be original. They must not be published or be under consideration for publication elsewhere, in whole or in part. It is required that the lead author of accepted papers complete and sign the MSU Press AEHM Author Publishing Agreement and provide it to the publisher upon acceptance.