Microbial degradation of pharmaceuticals in estuarine and coastal seawater Mark J. Benotti 1 , Bruce J. Brownawell * Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794-5000, USA Microbial degradation rates were measured for 19 structurally variable pharmaceuticals in wastewater-impacted estuarine and coastal seawater. article info Article history: Received 30 May 2008 Received in revised form 10 October 2008 Accepted 15 October 2008 Keywords: PPCP Biodegradation Sorption Estuary Caffeine abstract Microbial degradation rates were measured for 19 pharmaceuticals in estuarine and coastal surface water samples. Antipyrine, carbamazepine, cotinine, sulfamethoxazole, and trimethoprim were the most refractory (half-lives, t 1/2 ¼ 35 to >100 days), making them excellent candidates for wastewater tracers. Nicotine, acetaminophen, and fluoxetine were labile across all treatments (t 1/2 ¼ 0.68–11 days). Caffeine, diltiazem, and nifedipine were also and relatively labile in all but one of the treatments (t 1/2 ¼ 3.5–13 days). Microbial degradation of caffeine was further confirmed by production 14 CO 2 . The fastest decay of non-refractory compounds was always observed in more sewage-affected Jamaica Bay waters. Degra- dation rates for the majority of these pharmaceuticals are much slower than reported rates for small biomolecules, such as glucose and amino acids. Batch sorption experiments indicate that removal of these soluble pharmaceuticals from the water column to sediments is a relatively insignificant removal process in these receiving waters. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction The widespread occurrence of pharmaceuticals in surface waters (Kolpin et al., 2002; Boyd et al., 2003; Buerge et al., 2003; Bendz et al., 2005; Glassmeyer et al., 2005) attests to their lack of efficient removal during wastewater treatment (Ternes, 1998) and/ or their relative persistence in receiving waters. Depending on local industry and land-use practices, pharmaceutically active compounds can be introduced into aquatic systems by industrial waste (Daughton and Ternes, 1999), animal husbandry practices (Meyer et al., 2000), or municipal and domestic wastewater (Glassmeyer et al., 2005). Scientific interest in pharmaceutical occurrence in the envi- ronment arises largely from concern over possible toxicological risks and implications stemming from human exposure via drinking water (Schulman et al., 2002; Schwab et al., 2005), aquatic organism exposure (Jones et al., 2001), and the development of microbial resistance to antibiotics in aquatic ecosystems (Lear et al., 2002; Thomas et al., 2005). Detailed risk assessments will require improved understanding of environmental fate, including the rates and pathways of microbially-mediated degradation. Studies aimed at understanding pharmaceutical transformation in surface waters have focused more on photo-degradation than microbially-mediated degradation as a removal pathway. Researchers have observed that some pharmaceutical compounds, including ranitidine, sulfamethoxazole, diclofenac, ofloxacin, ator- vastatin and propanolol can be photo-degraded relatively rapidly (Buser et al., 1998; Andreozzi et al., 2003; Latch et al., 2003). Others, including carbamazepine, levofloxacin, cimetidine, and clofibric acid, are largely resistant to photo-degradation (Andreozzi et al., 2003; Latch et al., 2003; Lam and Mabury, 2005). In short, photo- degradation of pharmaceuticals varies throughout this structurally dissimilar class of compounds. Most microbially-mediated degradation studies with pharma- ceuticals have focused on removal during wastewater treatment (Ternes, 1998; Clara et al., 2005; Joss et al., 2005). On the other hand, there is relatively little information pertaining to microbial degradation rates of pharmaceuticals or other anthropogenic compounds in fresh waters (Bradley et al., 2007; Groning et al., 2007; Lim et al., 2008) and especial in marine or estuarine seawaters (Ying and Kookana, 2003). Four endocrine disrupting compounds (bisphenol A, 17b-estradiol, 17a-ethynylestradiol, 4-t- octyl phenol) were largely degraded in coastal seawater within 56 days, but only after a several-week lag time (Ying and Kookana, 2003). Degradation of 4-n-nonylphenol, which is likely more labile than the tetrapropylene based technical nonylphenol mixture of branched isomers in commercial products, was much more rapid under the same conditions. When incubations were conducted with oxic slurries of marine sediment, half-lives were shorter, * Corresponding author. Tel.: þ1 631 632 8658; fax: þ1 631 632 3072. E-mail address: bruce.brownawell@sunysb.edu (B.J. Brownawell). 1 Present address: Southern Nevada Water Authority, P.O. Box 99954, Las Vegas, NV 89193-9954, USA. Tel.: þ1 702 856 3684; fax: þ1 702 856 3647. mark.benotti@ snwa.com. Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol 0269-7491/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2008.10.009 Environmental Pollution 157 (2009) 994–1002