TY - JOUR
T1 - Fate and transport of chlormequat in subsurface environments
AU - Juhler, René K.
AU - Henriksen, Trine
AU - Rosenbom, Annette E.
AU - Kjær, Jeanne
PY - 2010/7
Y1 - 2010/7
N2 - Background, aim and scopeChlormequat
(Cq) is a plant growth regulator used throughout the world. Despite
indications of possible effects of Cq on mammalian health and fertility,
little is known about its fate and transport in subsurface
environments. The aim of this study was to determine the fate of Cq in
three Danish subsurface environments, in particular with respect to
retardation of Cq in the A and B horizons and the risk of leaching to
the aquatic environment. The study combines laboratory fate studies of
Cq sorption and dissipation with field scale monitoring of the
concentration of Cq in the subsurface environment, including artificial
drains.Materials and methodsFor
the laboratory studies, soil was sampled from the A and B horizons at
three Danish field research stations—two clayey till sites and one
coarse sandy site. Adsorption and desorption were described by means of
the distribution coefficient (K
d) and the Freundlich adsorption coefficient (K
F,ads). The dissipation rate was estimated using soil sampled from the A horizon at the three sites. Half life (DT50)
was calculated by approximation to first-order kinetics. A total of 282
water samples were collected at the sites under the field monitoring
study— groundwater from shallow monitoring screens located 1.5–4.5 m
b.g.s. at all three sites as well as drainage water from the two clayey
sites and porewater from suction cups at the sandy site, in both cases
from 1 m b.g.s. The samples were analysed using LC-MS/MS. The field
monitoring study was supported by hydrological modelling, which provided
an overall water balance and a description of soil water dynamics in
the vadose zone.ResultsThe DT50 of Cq from the A horizon ranged from 21 to 61 days. The Cq concentration-dependant distribution coefficient (K
d) ranged from 2 to 566 cm3/g (median 18 cm3/g), and was lowest in the sandy soil (both the A and B horizons). The K
F,ads ranged from 3 to 23 (µg1 − 1/n (cm3)1/n g−1) with the exponent (1/n)
ranging from 0.44 to 0.87, and was lowest in the soil from the sandy
site. Desorption of Cq was very low for the soil types investigated
(<10%w). Cq in concentrations exceeding the detection limit
(0.01 µg/L) was only found in two of the 282 water samples, the highest
concentration being 0.017 µg/L.
AB - Background, aim and scopeChlormequat
(Cq) is a plant growth regulator used throughout the world. Despite
indications of possible effects of Cq on mammalian health and fertility,
little is known about its fate and transport in subsurface
environments. The aim of this study was to determine the fate of Cq in
three Danish subsurface environments, in particular with respect to
retardation of Cq in the A and B horizons and the risk of leaching to
the aquatic environment. The study combines laboratory fate studies of
Cq sorption and dissipation with field scale monitoring of the
concentration of Cq in the subsurface environment, including artificial
drains.Materials and methodsFor
the laboratory studies, soil was sampled from the A and B horizons at
three Danish field research stations—two clayey till sites and one
coarse sandy site. Adsorption and desorption were described by means of
the distribution coefficient (K
d) and the Freundlich adsorption coefficient (K
F,ads). The dissipation rate was estimated using soil sampled from the A horizon at the three sites. Half life (DT50)
was calculated by approximation to first-order kinetics. A total of 282
water samples were collected at the sites under the field monitoring
study— groundwater from shallow monitoring screens located 1.5–4.5 m
b.g.s. at all three sites as well as drainage water from the two clayey
sites and porewater from suction cups at the sandy site, in both cases
from 1 m b.g.s. The samples were analysed using LC-MS/MS. The field
monitoring study was supported by hydrological modelling, which provided
an overall water balance and a description of soil water dynamics in
the vadose zone.ResultsThe DT50 of Cq from the A horizon ranged from 21 to 61 days. The Cq concentration-dependant distribution coefficient (K
d) ranged from 2 to 566 cm3/g (median 18 cm3/g), and was lowest in the sandy soil (both the A and B horizons). The K
F,ads ranged from 3 to 23 (µg1 − 1/n (cm3)1/n g−1) with the exponent (1/n)
ranging from 0.44 to 0.87, and was lowest in the soil from the sandy
site. Desorption of Cq was very low for the soil types investigated
(<10%w). Cq in concentrations exceeding the detection limit
(0.01 µg/L) was only found in two of the 282 water samples, the highest
concentration being 0.017 µg/L.
KW - CCC
KW - Chlormequat
KW - Chlorocholine chloride
KW - Cycocel
KW - Freundlich isotherm
KW - Groundwater
KW - Pesticide
KW - Quaternary ammonium herbicides
KW - Soil
KW - Sorption
UR - http://www.scopus.com/inward/record.url?scp=77954031782&partnerID=8YFLogxK
U2 - 10.1007/s11356-010-0303-5
DO - 10.1007/s11356-010-0303-5
M3 - Article
SN - 0944-1344
VL - 17
SP - 1245
EP - 1256
JO - Environmental Science and Pollution Research
JF - Environmental Science and Pollution Research
IS - 6
ER -