Izvorni znanstveni članak
https://doi.org/10.1515/aiht-2017-68-3063
Dissipation dynamics of terbuthylazine in soil during the maize growing season
Sanja Stipičević
; Institute for Medical Research and Occupational Health, Zagreb, Croatia
Gordana Mendaš
orcid.org/0000-0002-2661-2465
; Institute for Medical Research and Occupational Health, Zagreb, Croatia
Marija Dvoršćak
; Institute for Medical Research and Occupational Health, Zagreb, Croatia
Sanja Fingler
; Institute for Medical Research and Occupational Health, Zagreb, Croatia
Natalija Galzina
; Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
Klara Barić
; Faculty of Agriculture, University of Zagreb, Zagreb, Croatia
Sažetak
Ever since terbuthylazine (TBA) replaced atrazine in herbicide crop treatment, its much greater persistence has raised considerable environmental concern. The aim of our field experiment was to establish the dissipation dynamics of TBA and its degradation product desethylterbuthylazine (DET) in soil over five months of maize growth. We applied TBA as part of pre-emergent treatment in the regular and double-the-regular amounts. Soil samples were collected periodically at the following depths: 0-10 cm, 10-20 cm, 20-30 cm, and 30-50 cm. For TBA and DET soil residue analysis we used microwave-assisted extraction with methanol, followed by HPLC-UV/DAD. Regardless of the application rate, more than 80 % of the applied TBA dissipated from the first 50 cm of soil in the two months after herbicide application and 120 mm of rainfall. Three months later (at maize harvest), less than 4 % of total TBA remained in the soil, mostly in the top 20 cm rich with organic carbon on which TBA is likelier to adsorb. The loss of TBA from soil coincided with the rise in DET, especially the top soil layers, during the periods of low rainfall and highest soil temperatures. This points to biodegradation as the main route of TBA dissipation in humic soils. The applied amount had no significant effect on TBA dissipation in the top (humic) layers, but in the layers with less than 1 % of organic carbon, it was higher when the double-the-regular dose was applied.
Ključne riječi
application rate; desethylterbuthylazine; field conditions; herbicide; persistence
Hrčak ID:
191157
URI
Datum izdavanja:
20.12.2017.
Posjeta: 1.962 *