carbamazepine spiked soil (0.5–20 μg/g). Under realistic exposure conditions from
the use of recycled wastewater, carbamazepine concentrations were estimated to be
0.37 ng/L and 30 ng/kg in nectar and pollen, respectively. These findings were then
used to simulate pharmaceutical exposure to honeybees via contaminated nectar and
pollen at a landscape scale. This work illustrates a fundamental first step in assessing
the risk of pharmaceuticals to bees, although more work is needed to assess the
accumulation of a wider range of pharmaceuticals in nectar and pollen in fruiting
plants. Given the biological potency of pharmaceuticals, accumulation of these
chemicals in nectar and pollen suggests potential implications for honeybee health,
with unknown ecosystem consequences.
Plant uptake of the antidiabetic compound metformin, the antibiotic agent ciprofloxacin and the anti-coccidial narasin was investigated in a spiked soil exposure
with barley (Hordeum vulgare) (root, leaf, seed) and carrot Napoli (root, leaf)
[63]. Whilst metformin was the only pharmaceutical to be detected in all plant
compartments, all pharmaceuticals were measured at higher concentrations in
plant roots compared to their aboveground compartments in barley and carrot.
Higher concentrations in roots than aboveground compartments were similarly
observed for all pharmaceuticals tested where chemicals were spiked into a growth
medium by means of exposure [64, 65]. Interestingly, within the carrot root itself,
[57] observed that a majority of the veterinary medicines that were taken up were
associated with the outer layer of the carrot, with the exception of trimethoprim.
Similar results were found by Eggen et al. [63] where metformin BCFs for carrot and
potato (Solanum tuberosum) were higher in the peels than for the cores. These results
demonstrate that even within the root itself, there is variation in pharmaceutical
accumulation between the various plant organs.
However, other studies have observed that pharmaceutical distribution between
different plant organs is dependent on the plant species in question and the pharmaceutical itself. In spiked soil studies, differences in accumulation of pharmaceuticals
between radish leaf and radish root were also observed by [5], with higher concentrations in the roots reported for fluoxetine, triclosan and propranolol which translated into larger uptake factors (based on soil concentrations) for these chemicals in
the roots. Comparatively, higher total concentrations and larger uptake factors
(based on soil concentrations) for carbamazepine and diclofenac were observed in
the radish leaf in comparison to the root. Studies showing higher concentrations of
pharmaceuticals in aboveground parts compared to roots have been reported previously, when pharmaceuticals were added to soil-plant systems either via the addition
of biosolids or reclaimed wastewater [8, 13, 23]. The difference in accumulation
amongst pharmaceuticals clearly demonstrates the significant role of chemical
properties play in the distribution of pharmaceuticals within a single plant species.
Karnjanapiboonwong et al. [66] evaluated the accumulation of triclosan and
17α-ethynylestradiol (EE2) in the pinto bean (Phaseolus vulgaris) in both sand
and soil exposures. Plants accumulated EE2 at higher concentrations than triclosan
which was thought to be related to the sorption of these compounds in soil, with less
triclosan chemical available for plant uptake in comparison to the more bioavailable
EE2. In the soil exposure, both EE2 and triclosan accumulated to a greater extent in
190
L. J. Carter et al.
the use of recycled wastewater, carbamazepine concentrations were estimated to be
0.37 ng/L and 30 ng/kg in nectar and pollen, respectively. These findings were then
used to simulate pharmaceutical exposure to honeybees via contaminated nectar and
pollen at a landscape scale. This work illustrates a fundamental first step in assessing
the risk of pharmaceuticals to bees, although more work is needed to assess the
accumulation of a wider range of pharmaceuticals in nectar and pollen in fruiting
plants. Given the biological potency of pharmaceuticals, accumulation of these
chemicals in nectar and pollen suggests potential implications for honeybee health,
with unknown ecosystem consequences.
Plant uptake of the antidiabetic compound metformin, the antibiotic agent ciprofloxacin and the anti-coccidial narasin was investigated in a spiked soil exposure
with barley (Hordeum vulgare) (root, leaf, seed) and carrot Napoli (root, leaf)
[63]. Whilst metformin was the only pharmaceutical to be detected in all plant
compartments, all pharmaceuticals were measured at higher concentrations in
plant roots compared to their aboveground compartments in barley and carrot.
Higher concentrations in roots than aboveground compartments were similarly
observed for all pharmaceuticals tested where chemicals were spiked into a growth
medium by means of exposure [64, 65]. Interestingly, within the carrot root itself,
[57] observed that a majority of the veterinary medicines that were taken up were
associated with the outer layer of the carrot, with the exception of trimethoprim.
Similar results were found by Eggen et al. [63] where metformin BCFs for carrot and
potato (Solanum tuberosum) were higher in the peels than for the cores. These results
demonstrate that even within the root itself, there is variation in pharmaceutical
accumulation between the various plant organs.
However, other studies have observed that pharmaceutical distribution between
different plant organs is dependent on the plant species in question and the pharmaceutical itself. In spiked soil studies, differences in accumulation of pharmaceuticals
between radish leaf and radish root were also observed by [5], with higher concentrations in the roots reported for fluoxetine, triclosan and propranolol which translated into larger uptake factors (based on soil concentrations) for these chemicals in
the roots. Comparatively, higher total concentrations and larger uptake factors
(based on soil concentrations) for carbamazepine and diclofenac were observed in
the radish leaf in comparison to the root. Studies showing higher concentrations of
pharmaceuticals in aboveground parts compared to roots have been reported previously, when pharmaceuticals were added to soil-plant systems either via the addition
of biosolids or reclaimed wastewater [8, 13, 23]. The difference in accumulation
amongst pharmaceuticals clearly demonstrates the significant role of chemical
properties play in the distribution of pharmaceuticals within a single plant species.
Karnjanapiboonwong et al. [66] evaluated the accumulation of triclosan and
17α-ethynylestradiol (EE2) in the pinto bean (Phaseolus vulgaris) in both sand
and soil exposures. Plants accumulated EE2 at higher concentrations than triclosan
which was thought to be related to the sorption of these compounds in soil, with less
triclosan chemical available for plant uptake in comparison to the more bioavailable
EE2. In the soil exposure, both EE2 and triclosan accumulated to a greater extent in
190
L. J. Carter et al.