surface water samples were low (average of 0.031 μg/L), their study proposes a
highly sensitive new technique for the detection of drugs in aqueous samples.
Tanwar et al. [55] used two different approaches to determine NSAIDs in water:
stir bar sorptive extraction (SBSE) and passive sampling, followed by electrospray
ionization liquid chromatography-tandem mass spectrometry. Unfortunately they
only found undetectable levels of diclofenac, ketoprofen, mefenamic acid, naproxen,
and ibuprofen in samples taken from the Arno river in Italy.
The photolysis of ibuprofen was studied by exposure to a solar simulator in
solutions of fulvic acid isolated from Lake Pony in Antarctica: Suwannee River, GA,
United States. High-pressure liquid chromatography using a UV-visible dual wavelength detector found ibuprofen concentrations of 7.20 mgC/L in the Suwannee
River and 5.45 mgC/L in Lake Pony. The authors conclude that the photolytic fate of
ibuprofen in sunlit waters is affected by its concentration and the source of dissolved
organic matter present [56].
In the Doñana National Park in southern Spain, one of the most emblematic
protected areas in Europe included in the UNESCO World Heritage List, a 1-year
monitoring study was conducted to investigate the presence of NSAIDs in waters of
rivers and streams that affect the Park. Using high-performance liquid chromatography with diode matrix and in-line fluorescence detectors, the presence of
diclofenac was detected with a maximum average of 0.09 μg/L, ketoprofen
0.20 μg/L, naproxen 0.64 μg/L, and salicylic acid at 0.52 μg/L. Ibuprofen was the
compound found at the highest concentration levels, with an average of 1.21 μg/L.
The authors observed an increase in concentration levels in surface waters in the
summer months due to the reduction in river flows [22].
For their part, Ma et al. [40] developed a study to determine, through a direct
chiral analysis by means of LC-MS/MS, NSAIDs in the mainstream of the North
Canal Basin and its main tributaries (Qinghe, Bahe, Tonghui, and Liangshui) in the
most urbanized and industrialized zone in the northeast of Beijing (China). Their
analyses revealed that ibuprofen was the most abundant NSAID, with an average
concentration of its enantiomers of 114.9 ng/L, naproxen was also detectable at
concentrations of 43.2 ng/L, both presenting an excess of the S enantiomer. Therefore, they argued that to better understand the ecological risk, chiral contaminants
must be analyzed at enantiomeric levels. The authors indicate that this study is the
first to outline the enantiospecific occurrence of NSAIDs in surface waters in
Beijing.
Finally, another study that evaluated by means of LC-MS/MS the chiral fractions
of ibuprofen, ketoprofen, and naproxen was the one conducted by Camacho-Muñoz
and Kasprizyk-Hordern with surface water samples from a river in South West
England. They found ibuprofen as the maximum contaminant in both chiral fractions
(S 466 ng/L, R 1076 ng/L) followed by chiral fractions of naproxen (S 23.7 ng/L, R
25.9 ng/L) and finally those of ketoprofen (S 4.37 ng/L, R5.29 ng/L) [57].
This review has revealed the scarce research that still exists on the subject around
the world. It is a pressing need to further develop techniques with satisfactory
sensitivity to detect very low levels of NSAIDs and other pharmaceutical contaminants in natural water sources, in particular in the surface water of rivers, lakes, and
Worldwide Occurrence, Detection, and Fate of Nonsteroidal Anti-inflammatory. . .
69
highly sensitive new technique for the detection of drugs in aqueous samples.
Tanwar et al. [55] used two different approaches to determine NSAIDs in water:
stir bar sorptive extraction (SBSE) and passive sampling, followed by electrospray
ionization liquid chromatography-tandem mass spectrometry. Unfortunately they
only found undetectable levels of diclofenac, ketoprofen, mefenamic acid, naproxen,
and ibuprofen in samples taken from the Arno river in Italy.
The photolysis of ibuprofen was studied by exposure to a solar simulator in
solutions of fulvic acid isolated from Lake Pony in Antarctica: Suwannee River, GA,
United States. High-pressure liquid chromatography using a UV-visible dual wavelength detector found ibuprofen concentrations of 7.20 mgC/L in the Suwannee
River and 5.45 mgC/L in Lake Pony. The authors conclude that the photolytic fate of
ibuprofen in sunlit waters is affected by its concentration and the source of dissolved
organic matter present [56].
In the Doñana National Park in southern Spain, one of the most emblematic
protected areas in Europe included in the UNESCO World Heritage List, a 1-year
monitoring study was conducted to investigate the presence of NSAIDs in waters of
rivers and streams that affect the Park. Using high-performance liquid chromatography with diode matrix and in-line fluorescence detectors, the presence of
diclofenac was detected with a maximum average of 0.09 μg/L, ketoprofen
0.20 μg/L, naproxen 0.64 μg/L, and salicylic acid at 0.52 μg/L. Ibuprofen was the
compound found at the highest concentration levels, with an average of 1.21 μg/L.
The authors observed an increase in concentration levels in surface waters in the
summer months due to the reduction in river flows [22].
For their part, Ma et al. [40] developed a study to determine, through a direct
chiral analysis by means of LC-MS/MS, NSAIDs in the mainstream of the North
Canal Basin and its main tributaries (Qinghe, Bahe, Tonghui, and Liangshui) in the
most urbanized and industrialized zone in the northeast of Beijing (China). Their
analyses revealed that ibuprofen was the most abundant NSAID, with an average
concentration of its enantiomers of 114.9 ng/L, naproxen was also detectable at
concentrations of 43.2 ng/L, both presenting an excess of the S enantiomer. Therefore, they argued that to better understand the ecological risk, chiral contaminants
must be analyzed at enantiomeric levels. The authors indicate that this study is the
first to outline the enantiospecific occurrence of NSAIDs in surface waters in
Beijing.
Finally, another study that evaluated by means of LC-MS/MS the chiral fractions
of ibuprofen, ketoprofen, and naproxen was the one conducted by Camacho-Muñoz
and Kasprizyk-Hordern with surface water samples from a river in South West
England. They found ibuprofen as the maximum contaminant in both chiral fractions
(S 466 ng/L, R 1076 ng/L) followed by chiral fractions of naproxen (S 23.7 ng/L, R
25.9 ng/L) and finally those of ketoprofen (S 4.37 ng/L, R5.29 ng/L) [57].
This review has revealed the scarce research that still exists on the subject around
the world. It is a pressing need to further develop techniques with satisfactory
sensitivity to detect very low levels of NSAIDs and other pharmaceutical contaminants in natural water sources, in particular in the surface water of rivers, lakes, and
Worldwide Occurrence, Detection, and Fate of Nonsteroidal Anti-inflammatory. . .
69