Archives of Environmental Contamination and Toxicology

, Volume 44, Issue 1, pp 0067–0076

Aqueous-Phase Disappearance of Atrazine, Metolachlor, and Chlorpyrifos in Laboratory Aquaria and Outdoor Macrocosms

  • L. Mazanti
  • C. Rice
  • K. Bialek
  • D. Sparling
  • C. Stevenson
  • W. E. Johnson
  • P. Kangas
  • J. Rheinstein

DOI: 10.1007/s00244-002-1259-3

Cite this article as:
Mazanti, L., Rice, C., Bialek, K. et al. Arch. Environ. Contam. Toxicol. (2003) 44: 0067. doi:10.1007/s00244-002-1259-3

Abstract

Dissipation processes are described for a combination of commonly used pesticides—atrazine (6-chloro-4-ethylamino-6-isopropylamino-s-triazine), metolachlor (2-chloro-N-[2-ethyl-6-methyl-phenyl]-N-[2-methoxy-1-methylethyl] acetamide), and chlorpyrifos (O-O diethyl O-[3,5,6-trichloro-2-pyridinyl] phosphorothioate)—in a laboratory and outdoor pond systems. Dosing rates and timing were designed to duplicate those common in the mid-Atlantic Coastal Plain, USA. Treatments ranged from 2 and 2.5 mg/L to 0.2 and 0.25 mg/L respectively for atrazine and metolachlor, and chlorpyrifos was added at 1.0 and 0.1 mg/L in the aquaria and at 0.1 mg/L in the outdoor macrocosms. Chlorpyrifos disappearance was rapid in all of the systems and followed a two-phase sequence. Initial half-lives varied from 0.16 day to 0.38 day and showed similar rates in the aquaria and the outdoor systems. The second phase of the chlorpyrifis loss pattern was slower (18–20 days) in all the treatments except for the low herbicide treatment in the outdoor test, where it was 3.4 days. Compared to the outdoor system, herbicide losses were much slower in the aquaria, e.g., 150 days for atrazine and 55 days for metolachlor, and no appreciable loss of herbicide was apparent in the high-treated aquaria. In the outdoor systems, the half-lives for the low herbicide treatment were 27 days and 12 days, respectively, for atrazine and metolachlor, and 48 and 20 days, respectively for the high herbicide-treated pond. Very low levels of CIAT (6-amino-2-chloro-4-iso-propylamino-s-triazine) and CEAT (2-chloro-4-ethylamino-6-ethylamino-s-triazine), degradation products of atrazine, were observed in the outdoor studies.

Copyright information

© Springer-Verlag New York Inc. 2003

Authors and Affiliations

  • L. Mazanti
    • 1
  • C. Rice
    • 2
  • K. Bialek
    • 2
  • D. Sparling
    • 3
  • C. Stevenson
    • 4
  • W. E. Johnson
    • 5
  • P. Kangas
    • 6
  • J. Rheinstein
    • 2
  1. 1.U.S. Department of Agriculture, Natural Resources Conservation Service, Wetland Science Institute, 12311 Beech Forest Rd., Laurel, Maryland 20708, USAUS
  2. 2.U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Building 007, BARC-W, 1300 Balitmore Ave., Beltsville, Maryland 20705, USAUS
  3. 3.U.S. Geological Survey, Patuxent Wildlife Research Center, 11510 American Holly Dr., Laurel Maryland 20708-4017, USAUS
  4. 4.University of Maryland, Chesapeake Biological Laboratory, 1 Williams St., Solomons, Maryland 20688, USAUS
  5. 5.National Oceanographic and Atmospheric Administration, National Ocean Services, Center for Coastal Monitoring and Assessment, 1305 East West Highway, Silver Spring, Maryland 20910-3281, USAUS
  6. 6.University of Maryland, Biological Resources Engineering, 1457 Animal Science/Agricultural Engineering Bldg., College Park, Maryland 20742-2315, USAUS