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Oxytetracycline interactions at the soil–water interface: Effects of environmental surfaces on natural transformation and growth inhibition of Azotobacter vinelandii
Author(s) -
Goetsch Heather E.,
Mylon Steven E.,
Butler Shane,
Zilles Julie L.,
Nguyen Thanh H.
Publication year - 2012
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.1945
Subject(s) - adsorption , sorption , chemistry , azotobacter vinelandii , loam , environmental chemistry , oxytetracycline , nuclear chemistry , soil water , organic chemistry , biochemistry , soil science , geology , nitrogenase , nitrogen fixation , nitrogen , antibiotics
The mechanism of oxytetracycline (OTC) adsorption to a silty clay loam soil was investigated using sorption isotherm experiments, Fourier transform infrared spectroscopy (FTIR), and X‐ray diffraction spectroscopy (XRD). Sorption data fit well to a cation‐exchange capacity sorption model. Spectroscopic data indicate that the interactions between oxytetracycline and silty clay loam soil were primarily through electrostatic interactions between the protonated dimethylamino group of OTC and the negatively charged moieties on the surface of the soil. Based on XRD results, OTC adsorption appeared to inhibit the ethylene glycol solvation of the expandable clay minerals, suggesting that OTC had diffused into the clay interlayer space. The presence of adsorbed OTC did not significantly affect the transformation frequency of the soil bacterium Azotobacter vinelandii with plasmid DNA (soil alone 3 × 10 6 ± 4 × 10 6 and soil with adsorbed OTC 4 × 10 6 ± 0.5 × 10 6 ). Growth was inhibited by adsorbed OTC, although a greater mass of adsorbed OTC was required to achieve the same degree of inhibition as the system of dissolved OTC alone. These results suggest that the interactions of tetracyclines at the soil–water interface will affect the growth of sensitive microorganisms in soil microbial communities. Environ. Toxicol. Chem. 2012; 31: 2217–2224. © 2012 SETAC