16
K. Kuroda and J. Kobayashi
Tokyo were still vulnerable to pollution by sewage and that the pollution was still
ongoing.
1.3.4 Korea
Lee et al. (2019) investigated the occurrence of 44 CECs in groundwater in the rural
areas of Chungcheong Province, where agriculture such as rice, apple, and pear
cropping and cattle raising were actively practiced (Lee et al. 2019). A total of 31
CECs were detected in the surveyed wells, which were shallow (10–15 mbgl). The
detected concentrations of PPCPs (e.g., caffeine, up to 15 ng/L; crotamiton, up to
3.9 ng/L; carbamazepine, up to 0.26 ng/L) were lower than in the other Asian countries, presumably because the survey was conducted in rural areas with less PPCP
usage and more background groundwater. Nevertheless, the occurrence of the compounds showed an interesting contrast between agricultural and non-agricultural
areas; antibiotics, anthelmintics, β-blockers, and pesticides were detected only in
agricultural groundwater. In comparison, the concentrations of artificial sweeteners were significantly higher in non-agricultural groundwater than in agricultural
groundwater. These results clearly reflect the different human activities in these
areas.
1.3.5 Singapore
Tran et al. investigated the occurrence of 17 PPCPs (Tran et al. 2014b) and six artificial
sweeteners (Tran et al. 2014a) in surface water and groundwater in an urban area of
Singapore. In both studies, groundwater samples from ten wells in catchments with
sewerage systems, and those from a well in a catchment without known wastewater
sources (background groundwater), were surveyed in multiple sampling campaigns.
The surveyed catchments were served by relatively old and shallow sewer systems,
with the age of the sewer pipes being greater than 15–20 years. The surveyed wells
were shallow (4.7–11 mbgl).
Nine PPCPs (acetaminophen, clofibric acid, carbamazepine, caffeine, crotamiton, diclofenac, DEET, gemfibrozil, and salicylic acid) and three artificial sweeteners
(acesulfame, cyclamate, and saccharin) were detected in groundwater samples. In the
groundwater from sewered catchments, DEET (detection frequency: 100%), caffeine
(83%), carbamazepine (67%), acetaminophen (58%), and salicylic acid (58%) were
the most frequently detected PPCPs, with maximum concentrations of 16,249 ng/L
(caffeine), 4689 ng/L (acetaminophen), 3481 ng/L (DEET), and 1994 ng/L (salicylic
acid). The median concentrations in the groundwater samples (68.5 ng/L for caffeine, 49.5 ng/L for DEET, 23 ng/L for acetaminophen, 17 ng/L for salicylic acid,
K. Kuroda and J. Kobayashi
Tokyo were still vulnerable to pollution by sewage and that the pollution was still
ongoing.
1.3.4 Korea
Lee et al. (2019) investigated the occurrence of 44 CECs in groundwater in the rural
areas of Chungcheong Province, where agriculture such as rice, apple, and pear
cropping and cattle raising were actively practiced (Lee et al. 2019). A total of 31
CECs were detected in the surveyed wells, which were shallow (10–15 mbgl). The
detected concentrations of PPCPs (e.g., caffeine, up to 15 ng/L; crotamiton, up to
3.9 ng/L; carbamazepine, up to 0.26 ng/L) were lower than in the other Asian countries, presumably because the survey was conducted in rural areas with less PPCP
usage and more background groundwater. Nevertheless, the occurrence of the compounds showed an interesting contrast between agricultural and non-agricultural
areas; antibiotics, anthelmintics, β-blockers, and pesticides were detected only in
agricultural groundwater. In comparison, the concentrations of artificial sweeteners were significantly higher in non-agricultural groundwater than in agricultural
groundwater. These results clearly reflect the different human activities in these
areas.
1.3.5 Singapore
Tran et al. investigated the occurrence of 17 PPCPs (Tran et al. 2014b) and six artificial
sweeteners (Tran et al. 2014a) in surface water and groundwater in an urban area of
Singapore. In both studies, groundwater samples from ten wells in catchments with
sewerage systems, and those from a well in a catchment without known wastewater
sources (background groundwater), were surveyed in multiple sampling campaigns.
The surveyed catchments were served by relatively old and shallow sewer systems,
with the age of the sewer pipes being greater than 15–20 years. The surveyed wells
were shallow (4.7–11 mbgl).
Nine PPCPs (acetaminophen, clofibric acid, carbamazepine, caffeine, crotamiton, diclofenac, DEET, gemfibrozil, and salicylic acid) and three artificial sweeteners
(acesulfame, cyclamate, and saccharin) were detected in groundwater samples. In the
groundwater from sewered catchments, DEET (detection frequency: 100%), caffeine
(83%), carbamazepine (67%), acetaminophen (58%), and salicylic acid (58%) were
the most frequently detected PPCPs, with maximum concentrations of 16,249 ng/L
(caffeine), 4689 ng/L (acetaminophen), 3481 ng/L (DEET), and 1994 ng/L (salicylic
acid). The median concentrations in the groundwater samples (68.5 ng/L for caffeine, 49.5 ng/L for DEET, 23 ng/L for acetaminophen, 17 ng/L for salicylic acid,