title: Occurrence and Dissipation of the Antibiotics Sulfamethoxazole, Sulfadiazine, Trimethoprim, and Enrofloxacin in the Mekong Delta, Vietnam.
abstract: The Mekong Delta in Vietnam has seen a rapid development and intensification of aquaculture in the last decades, with a corresponding widespread use of antibiotics. This study provides information on current antibiotic use in freshwater aquaculture, as well as on resulting antibiotic concentrations in the aquatic environment of the Mekong Delta. Two major production steps, fish hatcheries and mature fish cultivation, were surveyed (50 fish farm interviews) for antibiotic use. Different water sources, including surface water, groundwater and piped water (164 water samples) were systematically screened for antibiotic residues. To better understand antibiotic fate under tropical conditions, the dissipation behavior of selected antibiotics in the aquatic environment was investigated for the first time in mesocosm experiments. None of the investigated antibiotics were detected in groundwater and piped water samples. Surface water, which is still often used for drinking and domestic purposes by local populations, contained median concentrations of 21 ng L-1 sulfamethoxazole (SMX), 4 ng L-1 sulfadiazine (SDZ), 17 ng L-1 trimethoprim (TRIM), and 12 ng L-1 enrofloxacin (ENRO). These concentrations were lower than the predicted no effect concentrations (PNECs) and minimum inhibitory concentrations (MICs), suggesting limited antibiotic-related risk to aquatic ecosystems in the monitored systems. The dissipation half-lives of the studied antibiotics ranged from <1 to 44 days, depending on the availability of sunlight and sediment. Among the studied antibiotics TRIM was the most persistent in water systems. TRIM was not susceptible to photodegradation, while the dissipation of ENRO and SDZ was influenced by photolysis. The recorded dissipation models gave good predictions of the occurrence and concentrations of TRIM, ENRO and SDZ in surface water. In summary, the currently measured concentrations of the investigated antibiotics are unlikely to cause immediate risks to the aquatic environment, yet the persistence of these antibiotics is of concern and might lead to chronic exposure of aquatic organisms as well as humans.
authors.affiliation: United Nations University, Institute for Environment and Human Security (UNU-EHS), Platz der Vereinten Nationen 1, 53113, Bonn, Germany; Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, University of Bonn, Nussallee 13, 53115, Bonn, Germany; Hue University, College of Sciences, Department of Chemistry, Nguyen Hue 77, Hue, Vietnam.
authors.forename: Chau
authors.initials: C
authors.lastname: Nguyen Dang Giang
authors.affiliation: United Nations University, Institute for Environment and Human Security (UNU-EHS), Platz der Vereinten Nationen 1, 53113, Bonn, Germany.
authors.forename: Zita
authors.initials: Z
authors.lastname: Sebesvari
authors.affiliation: United Nations University, Institute for Environment and Human Security (UNU-EHS), Platz der Vereinten Nationen 1, 53113, Bonn, Germany.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Renaud
authors.affiliation: Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, University of Bonn, Nussallee 13, 53115, Bonn, Germany.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Rosendahl
authors.affiliation: Department of Natural Resources and Environment-Thua Thien Hue province, Center for Natural resource and Environment monitoring, Pham Van Dong 173, Hue, Vietnam.
authors.forename: Quang
authors.initials: Q
authors.lastname: Hoang Minh
authors.affiliation: Institute of Crop Science and Resource Conservation (INRES), Soil Science and Soil Ecology, University of Bonn, Nussallee 13, 53115, Bonn, Germany.
authors.forename: Wulf
authors.initials: W
authors.lastname: Amelung
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D000077422:Enrofloxacin; D004784:Environmental Monitoring; D005398:Fisheries; D024841:Fluoroquinolones / Q000032:analysis*; D005618:Fresh Water; D005843:Geography; D060587:Groundwater; D018570:Risk Assessment; D045483:Rivers; D013411:Sulfadiazine / Q000032:analysis*; D013420:Sulfamethoxazole / Q000032:analysis*; D014295:Trimethoprim / Q000032:analysis*; D014744:Vietnam; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D014874:Water Pollutants, Chemical; D013411:Sulfadiazine; D000077422:Enrofloxacin; D014295:Trimethoprim; D013420:Sulfamethoxazole