Journal of Hazardous Materials 166 (2009) 297–308 Contents lists available at ScienceDirect Journal of Hazardous Materials journal homepage: www.elsevier.com/locate/jhazmat Appraisal of potential environmental risks associated with human antibiotic consumption in Turkey F. Ilter Turkdogan, Kaan Yetilmezsoy ∗ Department of Environmental Engineering, Yildiz Technical University, 34349 Yildiz, Besiktas, Istanbul, Turkey article info Article history: Received 14 September 2008 Received in revised form 9 November 2008 Accepted 10 November 2008 Available online 17 November 2008 Keywords: Antibiotic Medication Environmental risk Risk assessment Wastewater treatment plant abstract A comprehensive analysis of Turkish antibiotic data was conducted to evaluate potential environmental risks associated with antibiotic consumption in Turkey for year 2007. Antibiotics were defined for systemic use or group J01 of the WHO Anatomical Therapeutic Chemical (ATC) classification system. Total emis- sions and prescriptions for each ATC group were classified separately into 17 different J01 categories and three forms of medication (capsule/tablets, injectables and suspensions). Capsules and tablets were found as the most emitted form of medication in year 2007, with a total emission rate of about 585.5tons/year (76%). Total antibiotic emission rates including all forms of medications were determined to be about 664.2tons/year (86%) and 110.1tons/year (14%) for adult and pediatric patients, respectively. An envi- ronmental risk assessment of 8 human antibiotics was conducted according to the EU draft guidance (CEC/III/5504/94, draft 6, version 4) and the risk was indicated by the ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) for the aquatic environment. Available acute and chronic toxicity data were collected from the open peer-reviewed literature to derive PNEC. Risk quotients (PEC/PNEC) were then calculated for 8 pharmaceutical substances. PEC/PNEC ratio exceeded 1.0 for -lactams (cephalosporins and penicillins), fluoroquinolones, macrolides and aminoglycosides. The findings of this study concluded that the release of these compounds from wastewater treatment plants may potentially be of an important environmental concern based on today’s use of antibiotics in Turkey. © 2008 Elsevier B.V. All rights reserved. 1. Introduction Antibiotic consumption has received a lot of attention in the media in the last several years due to the increasing numbers of diseases and infections becoming resistant to traditional treat- ments for both humans and animals. However, after administration to humans and animals in hospitals or by prescription, a high percentage of antibiotics (up to 90%) are excreted unchanged via urine and/or feces into domestic sewage, and are discharged to wastewater treatment plants (WWTPs) without a second thought [1–5]. The resultant higher concentrations of antibiotics and other pharmaceutical products in urban waste streams have substantial impacts on the environment and human health, which are very dif- ficult to control using conventional practices. More importantly, in WWTPs, these pharmaceutical compounds are only partially removed and there is a potential for residues of antibiotics to be released through the WWTP effluents into the aquatic envi- ronment [3]. Therefore, urgent risk assessment and proper risk management are needed to ensure a robust and resilient control ∗ Corresponding author. Tel.: +90 212 3833033; fax: +90 212 2619041. E-mail address: yetilmez@yildiz.edu.tr (K. Yetilmezsoy). of antibiotic emissions for both developed and developing coun- tries. The main sources of antibiotics are homes, hospitals, nursing homes (medical treatment, disposal of unused medication), poultry and livestock feeding operations (growth promotion), and phar- maceutical manufacturers [6]. Kümmerer [7] has reported that if antibiotics used for veterinary purposes or as growth promot- ers in animal husbandry, they seep through the soil from manure and enter ground water. In addition, antibiotics may reach sur- face water and ground water, and potentially drinking water if they are not degraded or removed during sewage treatment, in soil or in other environmental compartments [7]. Although some antibiotics such as penicillins and ampicillin can be easily biode- graded in the aquatic environment, however, many antibiotics such as tetracyclines, erythromycin, metronidazole and sulphamethox- azole may not be readily destroyed by conventional wastewater treatment tecniques [6,8]. In addition, various antibiotics such as sulphonamides bind strongly to sludge, soil, sediments and manure, and may show a recalcitrant behaviour to a possible fur- ther biodegradation. Furthermore, many antibiotics are designed to be persistent and lipophilic, so that they can retain their chemi- cal structure long enough to do their therapeutic work [4]. Because of aquatic contamination by these persistent chemicals, bacteria 0304-3894/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2008.11.012