Part III Treatment of Pharmaceuticals in Drinking Water and Wastewater © 2008 by Taylor & Francis Group, LLC 217 10 Drugs in Drinking Water Treatment Options Howard S. Weinberg, Vanessa J. Pereira, and Zhengqi Ye 10.1 INTRODUCTION The high usage of drugs throughout the world, their partial metabolism after inges- tion,andinconsistenciesinthewaytheyaredisposedmaketheirpresenceinthe aquaticenvironmentinevitable.Theirsourcesinnaturalwatersarenotlimitedto excretion of parent compounds and their metabolites by individuals and pets but also include disposal of unused medications to sewage systems, underground leakage from sewage system infrastructures, release of treated or untreated hospital wastes, disposal by pharmacies and physicians, and humanitarian drug surplus to domestic sewage systems. Transmission routes include release to private septic elds; treated efuentfromdomesticsewagetreatmentplantsdischargedtosurfacewaters;over- owofuntreatedsewagefromstormeventsandsystemfailuresdirectlytosurface waters;transferofsewagesolidstoland;releasefromagriculture;dungfrommedi- cated domestic animals and conned animal feeding operations; direct release via washing, bathing, or swimming; discharges from industrial manufacturing and clandestine drug laboratories, as well as illicit drug usage; leaching from defective landlls; and release from aquaculture. 1 After release into the environment, most pharmaceutically active compounds (PhACs) are eventually transported to the aque- ousdomainandareexpectedtobeonlypartiallydegradedandtransformedinto other products by phototransformative, physicochemical, and biological degradation reactions. The environmental fate of only a fraction of these compounds has been evaluated in laboratory studies, and only recently has their occurrence in drinking Contents 10.1 Introduction 217 10.2 Occurrence in the Aquatic Environment 218 10.3 Drinking Water Treatment 218 10.3.1 Pretreatment 220 10.3.2 Filtrat ion 220 10.3.3 Chlorine-Based Disinfection 221 10.3.4 Ozone and Advanced Oxidation Treatment 222 10.3.5 Ultraviolet (UV) and Advanced Oxidation Treatment 223 10.4 Conclusion 225 References 226 © 2008 by Taylor & Francis Group, LLC 218 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems water been considered. 2 Their presence at low levels presents analytical challenges, and the environmental impact and public health effects of long-term, low-level expo- s u re and combinatory effects of these compounds requires further study. Particular concern should be raised over those compounds that resist wastewater and drinking watertreatment.TreatmentprocessesthatareexpectedtoefcientlyremovePhACs from water include adsorption using activated carbon, ozonation, ultraviolet (UV), and advanced oxidation processes. The concentrations investigated in laboratory- controlled evaluations of treatment options are often higher than those expected in the aquatic environment. This is a standard procedure in laboratory-scale studies for determination of rate constants and other fundamental process parameters minimiz - ing interference and analytical constraints, since working at these levels allows the analyte reduction to be followed over at least an order of magnitude without involv - ing extensive extractions or preparation procedures. Althoughthelifetimeingestionofdrinkingwatermayresultinconsumerexpo - suretoPhACsatanorderofmoreorlessthanasingletherapeuticdose,l ittlei s knownaboutlong-term,low-levelexposuretohumansorthepotentialsynergisms t h at may arise from exposure to multiple compounds. Consequently, it is prudent to considertheoptionsavailabletopreventPhACsfromreachingdrinkingwater. 10.2 OCCURRENCE IN THE AQUATIC ENVIRONMENT The occurrence of different classes of PhACs, such as analgesics and antiinam- matories, antibiotics, antiepileptics, beta-blockers, blood lipid regulators, contrast media, oral contraceptives, cytostatic, and bronchodilator drugs, has been reported in sewage, surface, ground and drinking water. 3,4,5–13 Maximum occurrence levels for some of these compounds reported in different countries are presented in Table 10.1, w h ichalsopresentsestimatesofquantitiesofPhACssoldforuseinhumanmedicine inGermanyin1997,wherescripdataaremorewidelyaccessiblethanintheUnited States,togetherwithsecondarywastewatertreatmentplant(WWTP)removalef - c i encies obtained by collecting composite raw inuent and nal efuent samples overaperiodof6days. 3 The reported WWTP removal efciencies were highly vari- able, and during other sampling events conducted at the same plant lower removal efciencies were observed. These results make clear the need to investigate further the fate and potential remediation options for those PhACs that were found to resist wastewatertreatmentandthatwerefoundindrinkingwater,suchasclobricacid, iopromide, carbamazepine, diclofenac, and ibuprofen. 10.3 DRINKING WATER TREATMENT A conventional surface water treatment process that consists of coagulation, oc- culation, sedimentation, ltration, and disinfection is often employed in drinking watertreatmentfacilities.OzoneandUVcanbeusedasoxidantsanddisinfectants, butchlorineandchloraminesaremostoftenemployedfornaldisinfectioninthe UnitedStatessothatapersistentresidualismaintainedinthedistributionsystem. © 2008 by Taylor & Francis Group, LLC DrugsinDrinkingWater 219 TABLE 10.1 Pharmaceuticals Sold in Germany, Wastewater Removal Efficiency in Germany, and Maximum Concentrations Reported by Several Authors in Different Countries (References Given in Parentheses) Maximum Concentrations Reported Compound Therapeutic Class PhACs Sold in Germany (Tons) WWTP Removal Efficiency (%) WWTP Effluent (µg/L) Surface Water (µg/L) Groundwater (µg/L) Drinking Water (µg/L) Acetaminophen Analgesics/ nonsteroidal antiinammatories >99 (3) 6.0 (6) 10 (7) Diclofenac 75 (3) 69 (3) 2.5 (6) 1.2 (6) 0.006 (3) Ibuprofen 180 (3) 90 (3) 85 (4) 2.7 (4) 0.003 (3) Ketoprofen 0.38 (6) 0.12 (6) Naproxen 66 (3) 3.5 (11) 0.4 (11) Oxytetracycline Antibiotics 0.34 (7) Tetracycline 1.0 (5) Ciprooxacin 0.132 (10) 0.07 (9) 0.018 (9) Carbamazepine Antiepileptic 80 (3) ~0 (3) 6.3 (6) 1.1 (6) 1.1 (4) 0.258 (12) Metoprolol Beta-blockers 52 (3) 67 (3) 2.2 (6) 2.2 (6) Clobric acid Antilipemic 51 (3) 1.6 (13) 0.55 (13) 4.0 (4) 0.270 (4) Iohexol Contrast media 7.0 (8) 0.5 (8) Iopromide 130 (3) 20 (8) 4.0 (8) 0.086 (3) 17B-ethinylestradiol Oral contraceptives 0.050 (3) 0.003 (4) 0.831 (7) Ifosfamide Cytostatic 2.9 (6) Salbutamol Bronchodilator >90 (3) 0.035 (6) © 2008 by Taylor & Francis Group, LLC 220 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems 10.3.1 PRETREATMENT ThepotentialfortheremovalofPhACsfromdrinkingwaterbydifferenttreatment processes has been reviewed. 14 Neither coagulation, which is expected to remove only hydrophobic compounds associated with particulate or colloidal material with highorganiccarboncontent,norocculationwouldbeefcienttoolsforremov- in gmostofthesecompoundsfromwater.Thiswasconrmedinabench-scale coagulation/occulation/sedimentation study on antibiotic removal with alum and iron salts. 15 Under simulated drinking water treatment conditions with ng/L initial concentrationsand68mg/LalumcoagulantdoseatpH6~8,theremovalrates of sulfamethoxazole and trimethoprim were below 20%, while erythromycin-H 2 O couldberemovedbyupto33%. 16 Erythromycin is much more hydrophobic than sulfamethoxazoleandtrimethoprim(logKow=3.06,0.89,and0.91,respectively) and is therefore more likely to partition onto solids and have higher removal rates. Diclofenac,carbamazepine,bezabrate,andclobricacidwerealsopoorlyremoved by ferric chloride precipitation. 17 10.3.2 FILTRATION Adsorptionusingactivatedcarboncouldplayanimportantroleintheremovalof PhACs,butcompetitionwithmorepolarorlargercompounds,includingnatural organicmatter(NOM),hasamajorimpact.Forexample,eventhoughtheaddition of 10 to 20 mg/L of powdered activated carbon (PAC) efciently removed seven antibiotics from distilled water (50 to greater than 99% removal), when the same experimentwasconductedinriverwatertheremovaldecreasedby10to20%. 14 Thepercentremovalofsulfonamides,trimethoprim,andcarbadoxinaltered(0.45 µm)surfacewatersamplewithdissolvedorganiccontentof10.7mg/Lrangedfrom 49 to 73% and 65 to 100% at PAC dosages of 10 and 20 mg/L, respectively. 15 In another laboratory-controlled batch study at an initial antibiotic concentration of 30 to 150 ng/L, sulfamethoxazole, trimethoprim, and erythromycin-H 2 Owereremoved throughPACadsorptionby21%,93%,and65%,respectively,inanaturalwaterof DOC3.5mg/Lwith4mg/LPACdoseandcontacttimeof4h. 16 These ndings show that even though the NOM in surface water may compete with the antibiotics for some of the adsorption sites on PAC, this process might still be somewhat effective asatreatmenttool. Membraneltrationprocessesareusedforwatertreatmentandvariousindustrial applications when production and distribution of water with high chemical and micro - bi ological quality is required. Processes such as reverse osmosis, nanoltration, and ultraltrationwerefoundtoefcientlyremovemanyPhACsfromwater. 18,19 However, a major disadvantage of using any of these ltration processes is that the removal of PhACs is accompanied by production of a rejection concentrate that will be much moreconcentratedthanthefeedwaterwithrespecttosuspendedanddissolvedcon - st ituents and will consequently require additional treatment and disposal. 20 © 2008 by Taylor & Francis Group, LLC DrugsinDrinkingWater 221 10.3.3 CHLORINE-BASED DISINFECTION Chlorine disinfectants, such as free chlorine and chloramines, are widely used in drinking water disinfection in the United States. Free aqueous chlorine (HOCl/OCl – ) can be formed by dissolving chlorine gas or hypochlorite into water, while chlora- mi nes can be formed by reaction of free chlorine with ammonia. Free chlorine, as a strong oxidant, is reactive toward many organic pollutants and produces chlorination byproducts.Chloramines,asrelativelyweakeroxidants,areexpectedtoreactmuch more slowly with organics. 21 AliphaticaminesreactrapidlywithHOCltoproduceN-chloramines, and direct correlations were observed between degree of nucleophilicity of amines and reaction rate with chlorine. 22 N-chlorocompoundswithahydrogenatomonthecarbonB-to the amine could undergo elimination reactions to form an imide, which subsequently hydrolyzes,resultinginbondcleavagebetweenthenitrogenandcarbonatomsand removal of the B-carbon s ide-chain. 23 Aromatic amines tend to form ring-substituted rather than N-chlorinated p roducts. Chlorination of phenol proceeds via a typical electrophilic substitution pathway. The phenolate anion has a higher electron den- si ty and, hence, reacts quite rapidly with HOCl. Among antibiotics, sulfonamides containanaromaticaminegroupthatissusceptibletofreechlorineattack,while the aliphatic amine groups in the structures of uoroquinolones, tetracyclines, and macrolides are likely to react with free chlorine to form N-chloroamines t hat can further decompose. The kinetics and mechanisms of sulfamethoxazole, trimethoprim, and three uoroquinolone antibiotics (ciprooxacin, enrooxacin, and umequine) in reaction with free chlorine and chlora mineshaveb eenstudied,albeitatafarlowerdisin- fectant-to-analyte ratio (~10) than would be typical with full-scale water treatment (~6000). 24–26 All these antibiotics react rapidly with free chlorine and at slower rates with preformed chloramines, except for umequine, lacking the characteristic piperizine ring in its structure, which exhibits no apparent reactivity toward chlorine oxidants. Sulfamethoxazole yields an N-chlorinated a dduct, which rearranges to a ringchlorinationproductorleadstoruptureofthesulfonamidemoietytoformthe major product N-chloro-p-benzoquinoneimine. R eactionoftrimethoprimappearsto occurprimarilyonthemolecule’strimethoxybenzylmoietyatpH<5,whileatpH≥5 an N-chlorinated i ntermediate is generated, which may react further or rearrange to anumberofstablesubstitutionproducts.Ciprooxacinreactsveryrapidlytoforma chloramine intermediate that spontaneously decays in water by piperazine fragmen- tat ion.Enrooxacinreactsrelativelyslowlytoformachlorammoniumintermedi- ate that can catalytically halogenate the parent in aqueous solution. The incomplete oxidationofuoroquinolonesmaynotcompletelyeliminatethebiologicaleffectof these compounds. 26 However, the substantial structural modication resulting from reactionofsulfamethoxazolewithfreechlorinemayleadtoasignicantreduction of that parent molecule’s antimicrobial activities. 25 Nevertheless, sulfonamides were demonstrated to be readily removed from drinking water at near neutral pH although barely affected by monochloramine. 27 The antimicrobial activity of trimethoprim mightnotbesignicantlyreducedviachlorinationduetotheformationofprimarily © 2008 by Taylor & Francis Group, LLC 222 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems stable and multiple-substituted products. 24 Thereactionkineticsofcarbadoxwith chlorine are highly pH dependent, with the apparent second-order rate constants rangingfrom51.8to3.15×10 4 M –1 s -1 at pH 4 to 11. 28 Carbadox was completely removedtobelowdetectionlevelsbybothfreechlorine(0.1mg/L)andmonochlo- ra mine(1mg/L)within1minofcontacttimeinbothdeionizedandsurfacewater. 27 However, chlorination did not appear to remove the antibacterial activity of the par- en t compound, as the identied chlorination byproducts of carbadox retain their bio- lo gically active functional groups. Although dechlorination agents were not used in many of these studies, they are employed when samples are collected for disinfection byproductanalysis,butonlyaftertheyhavebeenevaluatedtodetermineiftheydo not affect the stability of the analytes the samples are being collected for. Such an approach must also be used before eld samples are collected for the analysis of PhACs. Chlorine dioxide (ClO 2 )isanalternativetochlorinefordisinfection,anditisa highly selective oxidant for specic functional groups of organic compounds. 29 For example, sulfamethoxazole and roxithromycin were reactive to ClO 2 with second-order rateconstants(pH7,20ºC)of6.7×10 3 M –1 s –1 and2.2×10 2 M –1 s –1 ,respectively. 30 OrganicpollutantscanassociatewithdissolvedNOMintheaquaticphasevia thesamemechanismastheirsorptiontoparticulatenaturalorganicmatter.For example, the sorption coefcient ( K d, DOM )valuesoftetracyclinesonAldrichhumic acidwere2060and1430L/KgatpH4.6and6.1,respectively, 31 whichiscomparable to the K d valueoftetracycline.AssociationofantibioticswithdissolvedNOMmay facilitate their transport in the aquatic environment along with the dissolved NOM. 10.3.4 OZONE AND ADVANCED OXIDATION TREATMENT Ozone (O 3 ),withitshighstandardoxidationpotential,isexpectedtooxidizeorganic compounds more quickly than chlorine or chlorine dioxide. Ozonation is used in drinkingwatertreatmentplantstoachievedisinfectionandoxidationforpurposes such as color, taste and odor control, control of iron and manganese, destabilization of colloidal material to aid occulation, oxidation of disinfection byproduct (DBP) precursors,andeliminationoforganiccompounds. 32 Ozoneisaveryselectiveoxi- dant that will react with double bonds, activated aromatic compounds, and deproton- ate damines,whereashydroxyl(OH)radicalsgeneratedwhenozoneisemployedin advanced oxidation mode react with most water constituents with nearly diffusion controlled rates. 33 Diclofenac was efciently degraded in a semibatch reactor in dis- tilledandriverwateratanozonedoseof1mg/Lbutnotibuprofenorclobricacid (C o =2µg/Landreactiontime=10min). 34 On the other hand, greater than 70% removalofeachinapilot-scaleplantwasachievedusing2.5mg/Lozone. 2 These three compounds were effectively degraded by advanced oxidation processes (AOPs) using two O 3 to H 2 O 2 ratios (3.7:1.4 and 5.0:1.8 mg/mg). 34 Batch experiments have also been conducted to determine the degradation rate constants of several pharmaceuticals (bezabrate, carbamazepine, diazepam, diclofenac, 17 B-ethinylestradiol, i buprofen, sulfamethoxazole, and roxithromycin) with ozone and OH radicals. 35 Carbamazepine, diclofenac, 17B-ethinylestradiol, sulfamethoxazole, and roxithromycin were completely degraded during ozonation, © 2008 by Taylor & Francis Group, LLC DrugsinDrinkingWater 223 andtheratesobtainedinpurewatersolutionscouldefcientlybeappliedtopredict thesecompounds’behaviorinnaturalwaters(bankltrate,well,andlakewaters) withdifferentdissolvedorganiccarboncontentandalkalinity.Arapidreactionof ozone with the double bond in carbamazepine has been reported 36 as has the for- mation of byproducts containing quinazoline-based functional groups that can be furtheroxidizedbyreactionwithOHradicals.Moreover,inafull-scaleozonation plant, removal of sulfamethoxazole and carbamazepine, at occurrence levels of 9.7 and2.4ng/Linthesourcewater,tobelowdetectionlimit(<1ng/L)wasobserved. 2 Theactualmechanismofremoval,however,remainsunclear.Inapilot-scalestudy, samples of coagulated/settled/ltered (dual media) water illustrated little change in thelevelsofcarbamazepineintheplant’ssourcewater.However,whenozonewas introducedpriortocoagulation,66to96%reductionwasobserved,althoughitcould notbedeterminedifthiswastheresultofenhancedcoagulationratherthanozone alone. 37 10.3.5 ULTRAVIOLET (UV) AND ADVANCED OXIDATION TREATMENT EventhoughfewstudiesofdegradationofPhACsbyUVlighttreatmentprocess exist, in combination with ozone or hydrogen peroxide this process may effectively transform the compounds. UV radiation is widely used for drinking water disinfec - ti oninEurope.IntheUnitedStates,thistechnologyiscurrentlygainingimportance, since its use can reduce the chlorine dose applied for nal disinfection, therefore, decreasing the levels of DBPs formed. 38 AOPsusingUVinplaceofO 3 can also be usedforDBPprecursorremovalandareattractiveduetolowercostandlowerpoten- ti al for producing alternative chemical byproducts. Degradation of organic compounds can also be obtained using direct photolysis andAOPs.Foracompoundtobephotolabileitneedstohavethecapacitytoabsorb light. As a consequence of that light absorption, it will undergo transformation. It canalsoundergodegradationbyreceivingenergyfromotherexcitedspecies(sen - si tized photolysis) or by chemical reactions involving very reactive and short-lived species such as hydroxyl-radicals, peroxy-radicals, or singlet oxygen. 39 UVradiationcanbegeneratedusinglowpressure(LP)lampsthatemitmono- chromaticlightat254nmormediumpressure(MP)lampsthatemitabroadband rangingfrom205toabove500nm. 40 MP lamps were found to achieve a more effec- tivedegradationofbisphenolA,ethinylestradiol,andestradiolascomparedtodirect photolysisusingLPlamps. 41 The kinetic degradation constant of carbamazepine and reaction intermediates formedusingLPUV/H 2 O 2 have been studied. 42 Even though direct photolysis in the absence of H 2 O 2 leads to negligible degradation, an effective removal of carbamaze- pine can be obtained, and pathways were suggested to describe the degradation to acradine, a potentially mutagenic and carcinogenic byproduct. The effectiveness of ozonation and LP UV/H 2 O 2 processes were compared to testthedegradationofparacetamolanddiclofenacandidentifythemainbyproducts formed. 43,44 Both processes proved to be effective in inducing the degradation of both xenobiotics and achieved degrees of mineralization of approximately 30 and 40%forozonationandH 2 O 2 photolysis, respectively. © 2008 by Taylor & Francis Group, LLC 224 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems LP and MP ultraviolet systems were evaluated in batch-sale laboratory reac- tors 45,46 to investigate the UV photolysis and UV/H 2 O 2 oxidation of PhACs that were found to occur in the aquatic environment and belong to different therapeutic classes. The chemicals investigated were carbamazepine (antiepileptic agent), clobric acid (metabolite of the lipid regulator clobrate), iohexol (x-ray contrast agent), cipro -  o xacin (antibiotic), naproxen, and ketoprofen (both analgesics). Fundamental direct and indirect photolysis parameters obtained in laboratory-grade water were reported andusedtomodeltheUVphotolysisandUV/H 2 O 2 oxidation of the pharmaceuticals inasurfacewaterusingLPandMPlamps.MP-UVphotolysisandMP-UV/H 2 O 2 oxidation modeling predicted the experimental results very well. The LP-UV model predicted the experimental UV photolysis removals well but underestimated the LP- UV/H 2 O 2 oxidationresults.Overall,MPlampsprovedtobemoreefcientatmaxi- mizing the degradation of the selected group of compounds by both UV photolysis and UV/H 2 O 2 oxidation in the bench-scale experiments conducted. The UV uences required to achieve 50% removal of the selected pharmaceuticals from surface and laboratory-gradewaterrangedfrom34to3466mJ/cm 2 using MP-UV photolysis, 39 to 23105 mJ/cm 2 usingLP-UVphotolysis,91to257mJ/cm 2 using MP-UV/H 2 O 2 oxidation,and108to257mJ/cm 2 using LP-UV/H 2 O 2 oxidation. It should be emphasized that the irradiance measurement in a batch reactor is much less complex than in a full-scale UV reactor with multiple light sources. Future studiesshouldvalidatetheseresultsinpilotandfull-scalefacilitiesandevaluate whethertheuseofhighUVuencesandAOPsthatcoulddegradeawidevarietyof organiccompoundsareeconomicallyfeasibleandcompetitivewhencomparedto the use of other treatment processes (such as ozonation and membranes). The com - pa rison should take into consideration the possibility of byproduct formation during photolysis,ozonation,andAOPsaswellashowtodealwiththemembranerejection concentrate. P h otocatalysis is an AOP that has proven to be efcient for application in water disinfection and degradation of pollutants. It relies on the formation of strongly oxi - dative hydroxy radicals that inactivate microorganisms and degrade resilient organic micropollutantsrelativelynonselectivelyandmaybecarriedoutinthepresenceof a semiconductor (heterogeneous photocatalysis) or in the presence of chemical oxi - d a ntssuchasironandhydrogenperoxide(photo-Fenton). Among t he heterogeneous catalysts widely tested, titanium dioxide (TiO 2 ) appearstobeoneofthemostpromisingmaterialsinpromotingagoodlevelof disinfection and efcient destruction of chemical compounds. Its advantages include chemical inertness, photostability, absence of toxicity, and low cost, and it has there - f o re been considered for a wide range of applications. 47 To be catalytically active, titaniumdioxiderequiresirradiationwithasourceinawavelengthrangelowerthan 390nmthatwillinducethephotoexcitationofanelectron,sinceithasanenergy bandgapofabout3.2eV. After nding that photocatalysis in controlled laboratory-scale experiments appeared to reduce persistent substances such as NOM, carbamazepine, clobric acid,iomeprol,andiopromide(eveniftheyarepresentinacomplexmatrix), 48 the processwasevaluatedincombinationwithmicroltrationatthepilotscaletotestthe degradation of some of these compounds in a model solution without the presence © 2008 by Taylor & Francis Group, LLC DrugsinDrinkingWater 225 of NOM. 49 High photocatalytic degradation of carbamazepine and clobric acid was accompanied by elimination of the model solution’s dissolved organic carbon show- ingthatthexenobioticsweremineralizedtosomeextent.Ontheotherhand,the photocatalytic degradation of iomeprol was accompanied by formation of degrada- tion products and intermediates. The combination of photocatalysis with cross-ow microltration allowed the efcient separation and reuse of the TiO 2 particles. 10.4 CONCLUSION Despitethelow levelsofPhACsexpectedintheenvironment,theirconstantinfu- sion can cause them to become more persistent and, therefore, even if the half-lives of these compounds are short, long-term exposure effects and combinatory effects need to be addressed. The ecotoxicological potential of 10 prescription drugs has beenevaluated,andeventhoughformostofthesubstancestoxicitiesweremoder- ate , tests with combinations of various pharmaceuticals revealed stronger effects than expected from the effects measured individually. 50 The potential for indirect human exposure to pharmaceuticals from drinking water supplies was studied, and themarginbetweenpotentialindirectdailyexposureviadrinkingwateranddaily therapeuticdosewashigherbyatleastthreeordersofmagnitudeormore. 51 Despite these ndings, concerns are raised about long-term, low-level human exposure to pharmaceutical products, their metabolites, and degradation compounds via drink- ing water. Research has also shown that the presence of antibiotics in the aquatic environment poses a potential threat to ecosystem function and human health. 10,52 Minor side effects from prescribed drugs are common, and even though they are usually outweighed by the health benets of the medication, they can possibly have adverse effects in routine unintended exposure. This chapter has attempted to consider what does and does not work in remediat- in gthepresenceofdrugsindrinkingwater.Thereisnoquestionthatsubtherapeutic doses of these compounds are nding their way into the surface and groundwaters that ultimatelybecomeconsumers’drinkingwaterandthat,fornow,thelevelsfoundin that nished drinking water are most often close to the analytical limits of detection. Nevertheless, there are insufcient occurrence data for us to conclude that all conven- ti onaldrinkingwatertreatmentplantsaregeneratinganishedproductthatis“drug free.”Ifthesurfacewatersourceisimpactedbyanupstreamwastewaterdischarge fromamajorpopulationcenter,thereisastronglikelihoodthatasmalldownstream conventional drinking water plant will receive elevated levels of pharmaceutically active compounds that will survive to some degree in to the nished drinking water. One study even suggests that subsequent chlorination of such water could generate an even more toxic end product so that a switch to chloramination, already favored for reducing disinfection byproduct formation, might be preferable. Also, the introduc- ti on of advanced treatments such as AOPs or photolysis that target reactive centers in thechemicalcontaminantoffersomedegreeofremediationthat,whencoupledwith adsorption,appeartoofferafairdegreeofprotectiontotheconsumer. Furtherstudiesshouldfocusonevaluatingtheenvironmentalandhumanimpact of these compounds to determine to what extent they should be removed from drink- in gwater.Inaddition,economicviabilitystudiesofusinghigherUVuencesthan © 2008 by Taylor & Francis Group, LLC [...]...226 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems those typically employed for drinking water treatment should be conducted Furthermore, the fate of the target analytes during treatment should also be studied to determine if the pharmaceuticals are being mineralized or formation of photolysis products occurs Last, if photolysis byproduct formation occurs, their toxicity and. .. Meeting, San Francisco, CA, March 26–30, 2000, ENVR-045 18 Kim, S.D., Cho, J., Kim, I.S., Vanderford, B.J., and Snyder, S.A Occurrence and removal of pharmaceuticals and endocrine disruptors in South Korean surface, drinking, and waste waters, Water Res 2007, 41(5), 101 3 102 1 19 Yoon, Y., Westerhoff, P., Snyder, S.A., and Wert, E.C Nanofiltration and ultrafiltration of endocrine disrupting compounds, pharmaceuticals. .. Schittko, S., and Jekel, M Quantification of triiodinated benzene derivatives and X-ray contrast media in water samples by liquid chromatography-electrospray tandem mass spectrometry, J Chromatogr A 2001, 930, 127–134 9 Ye, Z., Weinberg, H.S., and Meyer, M.T Occurence of antibiotics in drinking water, 4th International Conference on Pharmaceuticals and Endocrine Disrupting Chemicals in Water, Minneapolis,... Chamberlain, E and Adams, C Oxidation of sulfonamides, macrolides, and carbadox with free chlorine and monochloramine, Water Res 2006, 40, 2517–2526 28 Shah, A.D., Kim, J.-H., and Huang, C.-H Reaction kinetics and transformation of carbadox and structurally related compounds with aqueous chlorine, Environ Sci Technol in press 29 Hoigné, J and Bader, H Kinetics of reactions of chlorine dioxide (OClO) in water. .. pharmaceuticals during ozonation and advanced oxidation processes, Environ Sci Technol 2003, 37, 101 6 102 4 © 2008 by Taylor & Francis Group, LLC 228 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems 36 McDowell, D.C., Huber, M.M., Wagner, M., von Gunten, U., and Ternes, T.A Ozonation of carbamazepine in drinking water: identification and kinetic study of major oxidation products,... P.M., and Imboden, D.M Environmental Organic Chemistry; Wiley-Interscience: New York, 1993 40 Sharpless, C.M and Linden, K.L Experimental and model comparisons of low- and medium-pressure Hg lamps for the direct and H2O2 assisted UV photodegradation of N-nitrosodimethylamine in simulated drinking water, Environ Sci Technol 2003, 37, 1933–1940 41 Rosenfeldt, E and Linden, K.G Degradation of endocrine... and Wert, E Fate of endocrine-disruptor, pharmaceutical, and personal care product chemicals during simulated drinking water treatment processes, Environ Sci Technol 2005, 39(17), 6649–6663 17 Sacher, F., Haist-Gulde, B., Brauch, H.-J., Zullei-Seibert, N., Preuss, G., Meisenheimer, M., Welsch, H., and Ternes, T.A Behavior of selected pharmaceuticals during drinking -water treatment, Book of Abstracts,... W., Bennett, E.R., and Letcher, R.J Ozone treatment and the depletion of detectable pharmaceuticals and atrazine herbicide in drinking water sourced from the Upper Detroit River, Ontario, Canada, Water Res 2006, 40, 2259–2266 38 Sharpless, C.M and Linden, K.L UV photolysis of nitrate: effects of natural organic matter and dissolved inorganic carbon and implications for UV water disinfection, Environ... Ed Water Quality and Treatment; 4th edition; McGraw-Hill: New York, 1990 33 von Gunten, U Ozonation of drinking water: part I oxidation kinetics and product formation, Water Res 2003, 37, 1443–1467 34 Zwiener, C and Frimmel, F.H Oxidative treatment of pharmaceuticals in water, Water Res 2000, 34, 1881–1885 35 Huber, M.M., Canonica, S., Park, G.-Y., and von Gunten, U Oxidation of pharmaceuticals during... A.K., and Reissman, D.B Persistence of pharmaceutical compounds and other organic wastewater contaminants in a conventional drinking -water- treatment plant, Sci Total Environ 2004, 329, 99–113 13 Ternes, T.A Occurrence of drugs in German sewage treatment plants and rivers, Water Res 1998, 32, 3245–3260 14 Snyder, S.A., Westerhoff, P., Yoon, Y., and Sedlak, D.L Pharmaceuticals, personal care products, and . Francis Group, LLC 220 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems 10. 3.1 PRETREATMENT ThepotentialfortheremovalofPhACsfromdrinkingwaterbydifferenttreatment processes. Group, LLC DrugsinDrinkingWater 221 10. 3.3 CHLORINE-BASED DISINFECTION Chlorine disinfectants, such as free chlorine and chloramines, are widely used in drinking water disinfection in the United States resist wastewatertreatmentandthatwerefoundindrinkingwater,suchasclobricacid, iopromide, carbamazepine, diclofenac, and ibuprofen. 10. 3 DRINKING WATER TREATMENT A conventional surface water treatment