Hong Kong, SAR and Taipei, Taiwan rank among the most densely populated cities globally. Dense populations result in concentrated use of pharmaceuticals and consumer products; however, diverse gradients of wastewater treatment capacities exist throughout Asia. Pharmaceuticals have received attention as contaminants of emerging concern (CECs) in freshwater, but environmental risks of CECs in urban coastal areas are poorly understood. We examined occurrence and water quality hazards of CECs in Hong Kong and Taipei. We collected wastewater from 11 sites across Hong Kong and Taipei, including eight primary treatment works in Kowloon and north-east Hong Kong Island, Stonecutters Island Sewage Treatment Works, Bali Sewage Treatment Plant, and Dihua Sewage Treatment Plant. We sampled over the 2015 summer monsoon and 2016 winter dry seasons to determine whether target analytes, including pharmaceuticals, drugs of abuse, and anthropogenic tracers differed among sewersheds. Target analytes were extracted, separated, and analyzed following previously reported methods using solid phase extraction and isotope-dilution liquid chromatography-tandem mass spectrometry. We determined potential coastal water quality hazards with a fish plasma modelling approach. We detected 12 of 23 target analytes: acetaminophen, benzoylecgonine, caffeine, carbamazepine, diclofenac, diltiazem, diphenhydramine, erythromycin, ketamine, sucralose, sulfamethoxazole, trimethoprim. Acetaminophen, caffeine, and sucralose were detected at the highest levels. While the primary cocaine metabolite, benzoylecgonine, was occasionally detected at low ng/L levels, ketamine, another drug of abuse, was observed at elevated levels in Hong Kong effluents (81 - 447 ng/L). Treatment efficiencies, effluent concentrations and estimated water quality hazards differed among Hong Kong and Taipei treatment plants. For example, while removal efficiencies at Stonecutters Island and Bali ranged from -70% to 1%, at the Dihua plant in Taipei, acetaminophen removal efficiency approached 100%. Additionally, therapeutic hazards differed across sewersheds. Results may inform decisions regarding waste stream assessment, apportioning, and management in urban coastal regions.

Examining urban metabolism and contaminants of emerging concern in coastal environments: A pilot study in Hong Kong and Taipei

253rd National Meeting (2017)

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