TY - JOUR
T1 - C, N, and H Isotope fractionation of the herbicide lsoproturon reflects different microbial transformation pathways
AU - Penning, Holger
AU - Sørensen, Sebastian R.
AU - Meyer, Armin H.
AU - Aamand, Jens
AU - Elsner, Martin
PY - 2010/4/1
Y1 - 2010/4/1
N2 - The fate of pesticides in the subsurface is of great interest to the
public, industry, and regulatory authorities. Compound-specific isotope
analysis (CSIA) is a promising tool complementary to existing methods
for elucidating pesticide degradation reactions. Here, we address three
different initial biotransformation reactions of the phenylurea
herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) in pure
culture experiments with bacterial and fungal strains. When analyzing
isotopic changes in different parts of the isoproturon molecule,
hydroxylation of the isopropyl group by fungi was found to be associated
with C and H isotope fractionation. In contrast, hydrolysis by Arthrobacter globiformis
D47 caused strong C and N isotope fractionation, albeit in a different
manner than abiotic hydrolysis so that isotope measurements can
distinguish between both modes of transformation. No significant isotope
fractionation was observed during N-demethylation by Sphingomonas
sp. SRS2. The observed isotope fractionation patterns were in agreement
with the type of reactions and elements involved. Moreover, their
substantially different nature suggests that isotope changes in natural
samples may be uniquely attributed to either pathway, allowing even to
distinguish the abiotic versus biotic nature of hydrolysis. Our
investigations show how characteristic isotope patterns may
significantly add to the present understanding of the environmental fate
of pesticides.
AB - The fate of pesticides in the subsurface is of great interest to the
public, industry, and regulatory authorities. Compound-specific isotope
analysis (CSIA) is a promising tool complementary to existing methods
for elucidating pesticide degradation reactions. Here, we address three
different initial biotransformation reactions of the phenylurea
herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) in pure
culture experiments with bacterial and fungal strains. When analyzing
isotopic changes in different parts of the isoproturon molecule,
hydroxylation of the isopropyl group by fungi was found to be associated
with C and H isotope fractionation. In contrast, hydrolysis by Arthrobacter globiformis
D47 caused strong C and N isotope fractionation, albeit in a different
manner than abiotic hydrolysis so that isotope measurements can
distinguish between both modes of transformation. No significant isotope
fractionation was observed during N-demethylation by Sphingomonas
sp. SRS2. The observed isotope fractionation patterns were in agreement
with the type of reactions and elements involved. Moreover, their
substantially different nature suggests that isotope changes in natural
samples may be uniquely attributed to either pathway, allowing even to
distinguish the abiotic versus biotic nature of hydrolysis. Our
investigations show how characteristic isotope patterns may
significantly add to the present understanding of the environmental fate
of pesticides.
UR - http://www.scopus.com/inward/record.url?scp=77950394116&partnerID=8YFLogxK
U2 - 10.1021/es9031858
DO - 10.1021/es9031858
M3 - Article
VL - 44
SP - 2372
EP - 2378
JO - Environmental Science & Technology
JF - Environmental Science & Technology
SN - 0013-936X
IS - 7
ER -