Soil matrix and macropore biodegradation of 2,4-D

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Journal of Environmental Quality

DOI:https://doi.org/10.2134/jeq1995.00472425002400040002x· OSTI ID:369884

Pivetz, B E ^[1]; Steenhuis, T S ^[2]

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1. ManTech Environmental Research Serv. Corp., Ada, OK (United States)
2. Cornell Univ., Ithaca, NY (United States)

Preferential flow of pesticides in macropores can lead to decreased travel times through the vadose zone and increased groundwater contamination. Macropores, however, may present a favorable environment for biodegradation because of greater oxygen, nutrient, and substrate supply, and higher microbial populations in earthworm burrows, compared to the soil matrix. The biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was measured in macropores and soil matrix of packed soil columns (7.0-cm diam., 10-cm length) and undisturbed cores contained as well-defined artificial macropore and the undisturbed cores contained earthworm-burrow macropores. A 50 {mu}g/L 2,4-D solution was continuously applied to the unsaturated soil surface and breakthrough curves (BTCs) indicating pesticide loss in the effluent were obtained from the soil matrix and macropore flow paths. Biodegradation rates were calculated separately for each flow path by comparing the BTCs to BTCs representing abiotic conditions, and dividing the 2,4-D loss by the travel time through each flow path. The biodegradation rates increased with time in both flow paths, and the final biodegradation rate in the macropore region surpassed that of the matrix, presumably because of increased microbial populations in the macropore. Complete loss of the 2,4-D in both flow paths was observed after continuous application of 2,4-D for 400 h, with maximum column-averaged 2,4-D loss rates of 0.879 {mu}g/(L h) in the matrix and 1.073 {mu}g/(L h) in the macropore. Biodegradation of 2,4-D was also observed in the macropore and matrix regions of the undisturbed soil cores. 19 refs., 7 figs., 2 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 369884
• Journal Information: Journal of Environmental Quality, Journal Name: Journal of Environmental Quality Journal Issue: 4 Vol. 24; ISSN JEVQAA; ISSN 0047-2425
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
55 BIOLOGY AND MEDICINE
BASIC STUDIES
BIODEGRADATION
ENVIRONMENTAL TRANSPORT
ORGANIC CHLORINE COMPOUNDS
PESTICIDES
POROSITY
REMEDIAL ACTION
SOILS