70
S. Mohapatra et al.
predicted based on a correlation between K OC and the octanol/water partition coefficient (K ow ). For hormones, such as 17β-estradiol (estradiol), estrone, and 17α-ethinyl
estradiol (EE2), the log K OC values are in the range of 3.40–3.81, 3.45–3.85, and
3.71–4.12, respectively. Hence, these compounds are expected to sorb significantly
onto the sediments (Lee et al. 2003a, b). For sediment and soil samples having
organic matter with low to intermediate polarity, Karickhoff (1981) suggested a correlation (Eq. 3.2) for predicting the organic carbon normalized sorption coefficient,
K OC (ml g
−1 ):
log K OC = 0.989 × logK OW − 0.346
(3.2)
The K ow values correspond to the partitioning of an organic compound between
the octanol phase and the aqueous phase at equilibrium. High K ow is a characteristic
of hydrophobic compounds having poor solubility. Such compounds also show a
higher tendency to sorb onto organic matter (Stangroom et al. 2000). Compounds
with log K ow < 2.5 are characterized by low sorption and higher bioavailability.
A moderate degree of sorption is expected for organics depicting log K ow values
between 2.5 and 4, while a high degree of sorption is expected for compounds with
log K ow values greater than 4.0 (Rogers 1996).
The log K D values for sorption of anti-influenza drugs (favipiravir, peramivir, laninamivir, laninamivir octanoate, oseltamivir, oseltamivir carboxylate, amantadine,
zanamivir) on river sediments were in the range of 0.1–1.4. The values are 3–4
orders of magnitude lower than for other pharmaceuticals, as reported by Azuma
et al. (2017). Such low values indicate a higher concentration of anti-influenza drugs
in the liquid phase compared to their loading on river sediments. The K OW values
for these drugs were in the range −7.1 to 2.7, i.e., below the threshold for sorption (Rogers 1996). Similarly, Radovi´ c et al. (2016) studied the sorption behavior of
17 pharmaceutical compounds onto four different river sediments. Sorption equilibrium could be described by the Freundlich isotherm, and sorption capacity followed
the order erythromycin » doxycycline » simvastatin » clopidogrel » bisoprolol »
lorazepam » azithromycin » diclofenac » atorvastatin » metoprolol » carbamazepine
» diazepam » trimethoprim » enalapril.
Radovi´ c et al. (2016) studied the sorption behavior of a variety of pharmaceuticals on sediments with varying sand, silt and clay content, as shown in Table 3.1.
The K D of any pharmaceutical was affected by the percentage distribution of clay,
silt, sand. Sediment-1, which was mainly composed of 93.50% fine-grained silt with
an average particle size of 0.003 mm, showed the greatest sorption capacity for the
pharmaceuticals studied. In contrast, sediment-4, which was mainly composed of
sandy gravel (94.74%) with granule size range 0.032–0.063 mm, showed the lowest
sorption capacity. The sorption capacity of various sediments for the studied pharmaceuticals followed the order: Sediment-1 (OC=1.28%) > Sediment-2 (OC=0.229%)
> Sediment-3 (OC= 0.06%)> Sediment-4 (OC=0%), such that sorption decreased
with decrease in the organic carbon (OC) content. A comparison of log K D values
for sorption of anti-influenza drugs on sandy and clayey sediments revealed higher
S. Mohapatra et al.
predicted based on a correlation between K OC and the octanol/water partition coefficient (K ow ). For hormones, such as 17β-estradiol (estradiol), estrone, and 17α-ethinyl
estradiol (EE2), the log K OC values are in the range of 3.40–3.81, 3.45–3.85, and
3.71–4.12, respectively. Hence, these compounds are expected to sorb significantly
onto the sediments (Lee et al. 2003a, b). For sediment and soil samples having
organic matter with low to intermediate polarity, Karickhoff (1981) suggested a correlation (Eq. 3.2) for predicting the organic carbon normalized sorption coefficient,
K OC (ml g
−1 ):
log K OC = 0.989 × logK OW − 0.346
(3.2)
The K ow values correspond to the partitioning of an organic compound between
the octanol phase and the aqueous phase at equilibrium. High K ow is a characteristic
of hydrophobic compounds having poor solubility. Such compounds also show a
higher tendency to sorb onto organic matter (Stangroom et al. 2000). Compounds
with log K ow < 2.5 are characterized by low sorption and higher bioavailability.
A moderate degree of sorption is expected for organics depicting log K ow values
between 2.5 and 4, while a high degree of sorption is expected for compounds with
log K ow values greater than 4.0 (Rogers 1996).
The log K D values for sorption of anti-influenza drugs (favipiravir, peramivir, laninamivir, laninamivir octanoate, oseltamivir, oseltamivir carboxylate, amantadine,
zanamivir) on river sediments were in the range of 0.1–1.4. The values are 3–4
orders of magnitude lower than for other pharmaceuticals, as reported by Azuma
et al. (2017). Such low values indicate a higher concentration of anti-influenza drugs
in the liquid phase compared to their loading on river sediments. The K OW values
for these drugs were in the range −7.1 to 2.7, i.e., below the threshold for sorption (Rogers 1996). Similarly, Radovi´ c et al. (2016) studied the sorption behavior of
17 pharmaceutical compounds onto four different river sediments. Sorption equilibrium could be described by the Freundlich isotherm, and sorption capacity followed
the order erythromycin » doxycycline » simvastatin » clopidogrel » bisoprolol »
lorazepam » azithromycin » diclofenac » atorvastatin » metoprolol » carbamazepine
» diazepam » trimethoprim » enalapril.
Radovi´ c et al. (2016) studied the sorption behavior of a variety of pharmaceuticals on sediments with varying sand, silt and clay content, as shown in Table 3.1.
The K D of any pharmaceutical was affected by the percentage distribution of clay,
silt, sand. Sediment-1, which was mainly composed of 93.50% fine-grained silt with
an average particle size of 0.003 mm, showed the greatest sorption capacity for the
pharmaceuticals studied. In contrast, sediment-4, which was mainly composed of
sandy gravel (94.74%) with granule size range 0.032–0.063 mm, showed the lowest
sorption capacity. The sorption capacity of various sediments for the studied pharmaceuticals followed the order: Sediment-1 (OC=1.28%) > Sediment-2 (OC=0.229%)
> Sediment-3 (OC= 0.06%)> Sediment-4 (OC=0%), such that sorption decreased
with decrease in the organic carbon (OC) content. A comparison of log K D values
for sorption of anti-influenza drugs on sandy and clayey sediments revealed higher