TY - JOUR
T1 - Distribution, fate and risk assessment of antibiotics in sewage treatment plants in Hong Kong, South China
AU - Leung, H. W.
AU - Minh, T. B.
AU - Murphy, M. B.
AU - Lam, James C.W.
AU - So, M. K.
AU - Martin, Michael
AU - Lam, Paul K.S.
AU - Richardson, B. J.
N1 - Funding Information:
We thank the staff of the Drainage Services Department and the Hospital Authority of the Hong Kong Special Administrative Region for sampling and providing relevant information. This study was funded by a Strategic Research Grant from City University of Hong Kong (Grant No. 7002005 ), and the Area of Excellence Scheme under the University Grants Committee of the Hong Kong Special Administrative Region, China (Project No. AoE/P-04/2004 ).
PY - 2012/7
Y1 - 2012/7
N2 - Occurrence, removal, consumption and environmental risks of sixteen antibiotics were investigated in several sewage treatment plants (STPs) featuring different treatment levels in Hong Kong, China. Cefalexin, ofloxacin and erythromycin-H2O were predominant with concentrations of 1020-5640, 142-7900 and 243-4740ng/L in influent, respectively; their mass loads were comparable to levels reported in urban regions in China and were at the high end of the range reported for western countries. The target antibiotics behaved differently depending on the treatment level employed at the STPs and relatively higher removal efficiencies (>70%) were observed for cefalexin, cefotaxime, amoxicillin, sulfamethoxazole and chloramphenicol during secondary treatment. ß-lactams were especially susceptible to removal via the activated sludge process while macrolides were recalcitrant (<20%) in the dissolved phase. Two fluoroquinolones, ofloxacin (4%) and norfloxacin (52%), differed greatly in their removal efficiencies, probably because of disparities in their pKa values which resulted in different sorption behaviour in sludge. Overall antibiotic consumption in Hong Kong was back-calculated based on influent mass flows and compared with available prescription and usage data. This model was verified by a good approximation of 82% and 141% to the predicted consumption of total ofloxacin, but a less accurate estimate was obtained for erythromycin usage. Risk assessment indicated that algae are susceptible to the environmental concentrations of amoxicillin as well as the mixture of the nine detected antibiotics in receiving surface waters.
AB - Occurrence, removal, consumption and environmental risks of sixteen antibiotics were investigated in several sewage treatment plants (STPs) featuring different treatment levels in Hong Kong, China. Cefalexin, ofloxacin and erythromycin-H2O were predominant with concentrations of 1020-5640, 142-7900 and 243-4740ng/L in influent, respectively; their mass loads were comparable to levels reported in urban regions in China and were at the high end of the range reported for western countries. The target antibiotics behaved differently depending on the treatment level employed at the STPs and relatively higher removal efficiencies (>70%) were observed for cefalexin, cefotaxime, amoxicillin, sulfamethoxazole and chloramphenicol during secondary treatment. ß-lactams were especially susceptible to removal via the activated sludge process while macrolides were recalcitrant (<20%) in the dissolved phase. Two fluoroquinolones, ofloxacin (4%) and norfloxacin (52%), differed greatly in their removal efficiencies, probably because of disparities in their pKa values which resulted in different sorption behaviour in sludge. Overall antibiotic consumption in Hong Kong was back-calculated based on influent mass flows and compared with available prescription and usage data. This model was verified by a good approximation of 82% and 141% to the predicted consumption of total ofloxacin, but a less accurate estimate was obtained for erythromycin usage. Risk assessment indicated that algae are susceptible to the environmental concentrations of amoxicillin as well as the mixture of the nine detected antibiotics in receiving surface waters.
KW - Antibiotics
KW - Consumption
KW - Hong Kong
KW - Removal efficiency
KW - Risk assessment
KW - Sewage treatment plants
UR - http://www.scopus.com/inward/record.url?scp=84858448162&partnerID=8YFLogxK
U2 - 10.1016/j.envint.2011.03.004
DO - 10.1016/j.envint.2011.03.004
M3 - Article
C2 - 21450345
AN - SCOPUS:84858448162
SN - 0160-4120
VL - 42
SP - 1
EP - 9
JO - Environment International
JF - Environment International
IS - 1
ER -