EuropeanJournalofChemistry3(4)(2012)480‐484

EuropeanJournalofChemistryISSN2153‐2249(Print)/ISSN2153‐2257(Online)2012EURJCHEM

DOI:10.5155/eurjchem.3.4.480‐484.698

EuropeanJournalofChemistryJournalhomepage:www.eurjchem.com

Thefateofleachateofpharmaceuticalslikeamoxicillin,ibuprofenandcaffeineinthesoilusingsoilcolumns

ShehdehJodeha,*,HalimehStaitib,MarwanHaddadb,TamaraRennoc,AbdelnaserZaidc,NidalJaradatcandMaherKharoafd

aChemistryDepartment,An‐NajahNationalUniversity,Nablus,11347,PalestinebWaterandEnvironmentalInstitute,An‐NajahNationalUniversity,Nablus,11347,PalestinecPharmacyDepartment,An‐NajahNationalUniversity,Nablus,11347,PalestinedJerusalemPharmaceuticalCompany,Ramallah,11347,Palestine

*Correspondingauthorat:ChemistryDepartment,An‐NajahNationalUniversity,Nablus,11347,Palestine.Tel.:+970.59.959049;Fax:+970.59.2345982.E‐mailaddress:sjodeh@najah.edu(S.Jodeh).

ARTICLEINFORMATION ABSTRACTReceived:30October2012Accepted:07November2012Online:31December2012

KEYWORDS

Fromanenvironmentalengineeringpointofview,pharmaceuticalssuchasantibioticsareagroup of man‐made chemicals of concern entering the environment in concentrations atwhich,thehealtheffectsareunknown.Theproblemthatmaybecreatedbythepresenceofantibioticsatlowconcentrationsintheenvironmentisthedevelopmentofantibioticresistantmicroorganisms. In this study, three pharmaceutical drugsmanufactured in Palestinewerestudiedinwastewaterandtheiradsorptioninagriculturesoilwasstudiedusingsoilcolumns.During thestudyofsoil columns, itwasnoted that theconcentrationof caffeine in leachatewashigher than thatof ibuprofenandamoxicillin,ascaffeinehashigheraqueoussolubility.Ibuprofen and amoxicillinwere present in leachatewith very small concentrations, due totheir degradationanddecomposition into other substances thatmaybeharmful, andaffectthenaturalpropertiesofsoil,groundwaterandhumanhealth.Thedecompositionpercentagesof the pharmaceuticals in the soil columns were 97.82, 97.88 and 86.52% for amoxicillin,ibuprofen and caffeine for one year’s study, respectively. For the fifteen years, thedecomposition percentages were 94.04, 96.60 and 93.70% for amoxicillin, ibuprofen andcaffeine,respectively.

KineticsLeachateAdsorptionPharmaceuticalsChemicaloxygendemand(COD)Biochemicaloxygendemand(BOD)

1.Introduction

Landfillleachatesareheavilyloadedwithdifferenttypesoforganic and inorganic contaminants and present amajor riskwithrespecttocontaminationofnaturalwaterresources[1].Inunprotectedlandfills,leachatesinfiltrateverticallythroughthevadose soil zone below the landfill and eventually reach thegroundwater aquifer, forming anaerobic plumes [2], that canpose a serious threat to drinking water resources [3]. Inlandfills, which include a leachate collection system, it ismandatorytotreatthecollectedleachatebeforeitsreleaseintoambientsurfacewaters.

Newpharmaceuticalresiduesintheenvironment,andtheirpotential toxic effects, already have been recognized as anemerging research area in environmental chemistry [4]. Abetterknowledgeoftheoccurrenceandfateofpharmaceuticalsreleasetotheenvironmentwillattainaproperriskassessmentforriverbasins;wetlandsandothersrelatedecosystems[5].Itis nowwell established that pharmaceuticals are widespreadcontaminants of wastewater effluents [6‐7], surface anddrinking waters, but limited publications are concerned withtheiroccurrenceinterrestrialecosystems[4].

Drinking water for major areas in the world is producedfrom surface as well as groundwater. Filtering cannot beachieved for all pollutants, neither from surface to ground‐water, nor from soils to streams or wells. Soil infiltration isbecomingmorecommonforwastewatereffluentsindevelopedcountriesasatertiarytreatmentprocessandawayofreusing

waterasresourcesbecomescarcer[8].Theuseofwastewater,often untreated, to irrigate soils occurs widely in lessdevelopedcountriesandhasdonesoformanyyears[9].

In different countries including Palestine, drugs and theirmetabolites have been repeatedly detected in ground andsurface waters and occasionally in drinking water [10‐12].After intake, the drugs ormetabolites are excreted and reachthe sewage plant through the sewage system. Because of theabsence of any specific absorption or degradation system,drugsandtheirmetabolitesreachthepondwaterandgroundwater [10‐12]. Further sources include the improper disposalof residual or outdated drugs through the sewage systems ofprivate households, and the improper disposal on dumps,whichpossiblybypassesthesewageplant.

In general, most pharmaceuticals in the environment aretheresultofhumanexcretionbutalsopharmaceuticalsmaybefound in lowconcentrations in landfill leachate,discharged towastewater treatment plants. Although the science is limited,thismightsuggestthatlandfilldisposalofpharmaceuticalsmaybe a low‐risk practice. Wastewater treatment plants are notdesignedtoremovepharmaceuticals,sothisalsocanbeviewedas a minor pathway by which pharmaceuticals reach theenvironment.Accordingtoa2007report[13]preparedfortheOregonAssociationofCleanWaterAgencies,onlyafewstudiesprior to that date had examined concentrations of pharma‐ceutical compounds in leachate from lined landfills and all ofthose studies focused on landfills in countries other than theU.S.[14].Thereportconcludedthattheoreticalcalculationsand

Jodehetal./EuropeanJournalofChemistry3(4)(2012)480‐484 481

field data suggest that drugs disposed of in municipal solidwaste landfills contribute only a small fraction (< 1%) of thetotal loadofpharmaceuticalcompoundsdischargedtosurfacewater viamunicipalwastewater treatment plants and landfillleachate treatment systems. In most developed countries,landfillsarenowequippedwithengineeredlinersandleachatecollectionsystemsinordertominimizetheadverseimpactsofleachateonthesurroundingenvironment[15].

In this study three selected pharmaceutical productsmanufactured by major drug companies in Palestine werechosen, to study their presence in the wastewater of thosecompanies and to study their leachate in soil using a plasticpipescolumnsfilledwithagriculturesoil.Theobjectiveofthisstudy is to understand the fate of those drugs, wastepenetrating groundwater through soil using soil columns andadddifferentconcentrationsofthosedrugsinthecolumnsandcollect the leachates out of those columns. This will beexplainedindetailsinthemethodsandmaterialssection.2.Experimental

The research experimental work basically depends ondetermining the concentration of residues of amoxicillin,ibuprofen, and caffeine (Scheme 1) versus time in soil, andleachate,whichisconsideredbythreeterms,Zero‐term,short‐term (one year), and long‐term concentration (fifteen years)whichallofwhichwillbeexplainedlater.

Amoxicillin(2S,5R,6R)‐6‐{[(2R)‐2‐amino‐2‐(4‐hydroxyphenyl)‐acetyl]amino}‐3,3‐dimethyl‐7‐oxo‐4‐thia‐1‐azabicyclo[3.2.0]heptane‐2‐carboxylicacid

Ibuprofen(RS)‐2‐(4‐(2‐methylpropyl)phenyl)propanoicacid

Caffeine

1,3,7‐trimethyl‐1H‐purine‐2,6(3H,7H)‐dione

Scheme12.1.Instrumentation

High‐Performance Liquid Chromatography (HPLC)consisted of a Waters Millipore (Bedford, MA) 6000A pump,SpectraPhysics (San Jose, CA) 3000A automatic injector withcolumnheater,Waters/Millipore440dualfixedwavelengthUVdetector, Spectra PhysicsWinner data collection systemwith4270integratorandacolumnofWhatman10cmPartishere5

C18µmpacking. Theinjectionvolumeusedwas10µLwithaflowrateof1mL/min.Datawascollectedat254,230and256nmfor ibuprofen, amoxicillin, andcaffeine, respectively at2.5points/second.Column temperaturewas regulatedat30 oC, afewdegreesaboveambient temperature tostabilize retentiontime.2.2.Soilcolumnpreparation

Seven columnsof Polyvinyl chloride (PVC) (15 x 100 cm)werepreparedafterfillingthemwithsievedsoil˂63mm.Allofthecolumnswerepreparedbyaddingdistilledwater throughthem to insure that there are no gaps or spaces between thesoilpieces.Thefirstcolumnwasusedasblankwhichhadonlysoil and distilled water. The second column represented oneyear’sexpectationtoseewhatwillhappento thedrugafter itwas adsorbed by soil. The second and third columns werepolluted using amoxicillin contained at 50 mg/L, solutioncontaining0.2034 g for oneyear and3.054 g in4.0L for 15‐years.Usuallyweadd4litersof50mg/Lofamoxicillintothesoil in the column to study the adsorption and leachate. Thethird columnwasused for the studyof the adsorption for 15years, which is basically adding 4 liters of 750 mg/L ofamoxicillin and studying the adsorption and leachate. Thefourth column was polluted with Ibuprofen; a solutioncontaining0.2034gof Ibuprofen ina4.0L containerwith50mg/Lwaspreparedandaddedtothecolumn,thereforeitwaslabeled(ibuprofenone‐year).Thefifthcolumncontained3.054g of Ibuprofen powder in 4.0 L, contained 150 mg/L ofibuprofen and labeled ibuprofen 15 years. These labels arerelated with the study of the fate of pharmaceuticals in oneyearand15years,respectively.Thesixthandseventhcolumnswere polluted using caffeine of 50mg/L solutions containing0.2034 g for one year, and 3.054 g for 15‐years. After theadditionofpharmaceuticalstothecolumns,soilcolumnswereleftfor24hrstoensureacompleteadsorptionprocessonsoil.Ofcourseeachcolumnwaspreparedbyaddingdistilledwaterbeforeadditiondrugs towet thecolumnsandmakesure thattherewasnoairbetweensoilgranulesandthewaterrunningsmoothlyinthecolumns.

In Palestine it rains an average of 43 days a year andweusedthisnumbertoaddthedrugstocolumn43timesandwecollected the leachate every 72 hours for HPLC analysis. Theleachateswerecentrifugedat1100gfor20min,andthen,thesupernatant solution was decanted, filtered through 0.45 µmAcrodiskfilters,andstoredat4oCbeforeanalysisusingHPLC.At the end of the experiment, each soil columnwas cut intoeight parts (0‐25, 25‐50, 50‐75, 75‐100, 100‐125, 125‐150,150‐175,175‐200cm).

Thesoilwastakenoutandextractedwithdouble‐deionizedwater (DDW) at 18 MΩ resistivity. All pharmaceuticals andchemicalswerepurchasedfromtheSunCompanyinPalestineand all chemicals with of very high purity. The otherpharmaceutical materials (samples for studies) weremanufactured in Palestine (Beir Zeit, Dar El‐shefa andJerusalemPharmaceuticalCompanies).

All standard solutions used in the experiment wereanalytical reagent grade or of extra pure quality unlessotherwiseindicated.Allglasswareandplasticcontainersweresoaked overnight in 10% nitric acid and rinsed with DDWbeforetheywereusedforanalysis.2.3.HPLCscanningofamoxicillin

FordetectionthewavelengthofpharmaceuticalsusingUVdetector, chemicals and reagents like acetonitrile solution,monobasic potassium phosphate, sodium hydroxide, distilledwater,and thepharmaceuticalswereused. In thisexperimentthreesolutionswereprepared:

Mobile phase solution prepared from a diluent andacetonitrile (96:4), the diluent was a mixture of 6.9 g of

482 Jodehetal./EuropeanJournalofChemistry3(4)(2012)480‐484monobasicpotassiumphosphatewith1000mLdistilledwater,adjustedwith45%NaOHsolutiontoapHof5.0±0.1.

The standard solution was prepared by dissolving anaccurately weighed quantity of the pharmaceuticals to bestudied in diluents to obtain a solution having a knownconcentrationofabout1.2mg/mL(degassedbyultrasonicationbeforeuse).The retention timeandwavelength foreachdrugareshowninTable1.

Table 1. Wavelengths and retention times for the pharmaceuticals usingHPLC.Drugname Wavelength(nm) Retentiontime(min)Amoxicillin 230 9.16Ibuprofen 254 2.00Caffeine 256 20.712.4.Calibrationcurves

Standardcalibrationcurves foramoxicillin, ibuprofen,andcaffeine weremade by preparing a stock solution containing500 mg/L of ibuprofen, amoxicillin and caffeine as referencestandardsand then transferred into100mLvolumetric flasksof10,30,40,50and60mg/Lofeachcompound.Absorbancereadingswere recorded at 254nm for ibuprofen, 230nm foramoxicillin,andat256nmforcaffeine.3.Resultsanddiscussion3.1.Soiltests

Samplesofredsoilwereanalyzedinordertoevaluatethesoil texture, moisture, pH value, and specific gravity. Table 2showstheresultsobtainedfromthesetests.

From the table it was noticed that the silt percentage islarger than the clay and both organic carbon and organicmatterwere highwhich increased the adsorption capacity ofdrugs.

Table 2. Soil specific gravity, pH, texture, and moisture for soil beforepollution.Soilproperties ResultSpecificgravity 2.34pH 7.14Clay,% 41Silt,% 71Moisturecontent,% 29Organiccarbon,% 7.34Organicmatter,% 10.363.2.Pollutedleachatewaterfromibuprofen,amoxicillin,andcaffeineanalysis

Theleachatewaterthatflowedfromeachsoilcolumnwaskept in well closed High Density Polyethylene (HDPE)containersandstoredinrefrigeratorat7oCandthenanalyzedby HPLC. The absorbance readings were recorded, andconvertedtoconcentrations(mg/L)usingstandardcalibrationcurves.TheresultsareshowninFigure1‐3forthethreedrugsand this data represents the kinetic study for the leachate inoneand15years,respectively.

Fromtheresultsthathavebeenobtained,thespeedofflowofwaterinblankcolumnsismuchhigherthaninothercolumnswith added medications because of the lack soil correlationwithanyotheradditives.

Hydrolysis of ibuprofen, amoxicillin, and caffeine inpollutedwaterfollowedfirstorderkineticsasprescribedintheplottedgraphs(Figure1,2and3).StraightlineswereobtainedafterplottingLn[A]vs.timeanditagreeswithpreviousstudies[18‐21].

Asprescribed in Figure2. The concentrationmeasuredofibuprofeninpollutedwaterwasdecreasedamongtheoneyearand 15‐years columns, due to the limited mobility of thecompoundandrapiddegradation,andbecausethesoilusedin

theexperimenthasapHof7.41.Ibuprofendissolvedinacidicmediamorethananyotherpharmaceuticals[18].

Itwasnotedthatamoxicillinconcentrationsdecreasedlessdramaticallyandrapidlythanibuprofenduetoitsnature,asitdecomposesduringthefirst6hoursoftime[22].Whileitwasobserved that the concentrations of caffeine were obviouslylarger than both ibuprofen and amoxicillin, this is becausecaffeineisamorewatersolublecompound[23].

Figure 1. Ln [A] versus time for polluted water flowed from amoxicillincolumnforoneandfifteenyears.

Figure2. Ln[A]versustimeforpollutedwaterflowedfromibuprofen(one‐yearandfifteenyears).

Figure3. Ln [A]versus time forpollutedwater flowed fromcaffeine (one‐yearandfifteenyears).

Jodehetal./EuropeanJournalofChemistry3(4)(2012)480‐484 483

Table3.Massbalanceforamoxicillin,ibuprofenandcaffeine.

Totalconcentrationinleachate(mg/L)/43days

Totalconcentrationadsorbedonsoil(mg/L)/43days

Decomposed(%)

Amoxicillinone‐year2150(mg/L) 40.42 9.90 97.66Amoxicillin15‐year32,250(3.23%) 1213.46 706.92 94.04Ibuprofenone‐year2150(mg/L) 11.18 34.3 97.88Ibuprofen15‐year32,250(3.23%) 258.00 1161.00 96.60Caffeineoneyear2150(mg/L) 96.75 38.70 93.70Caffeine15‐year32,250(3.23%) 3010.00 1400 86.323.3.Distributionofpharmaceuticalinsoilcolumnsafterfinishingtheleachatestudy

Afterfinishingtheleachatestudiesfromthecolumnsinoneyear and fifteen year studies, the columns were cut‐off for 8equalpartsandarepresentativesampleofsoilwastakenfromeachpartasdescribedinSection2.2toseethedistributionofadsorptionineachlayerofthecolumns.

Fromtheresultsofthispartofstudy, thepharmaceuticalswere distributed along the columns. Amoxicillin in one andfifteenyearssoilcolumns(Figure4and5),showedthehighestconcentrations in the region of 0‐25 cm, and the amount ofamoxicillinwas rapidly decreased as increasing in soil depth,whichwasanindicationofamoxicillinlowmobilityinsoilduetoitsrapiddegradation[22].

Figure 4. Amoxicillin, ibuprofen,andcaffeineconcentrationsmeasured insoillayersforoneyear.

In Ibuprofen one year and fifteen years soil columns(Figure4and5),thehighestconcentrationswerefoundintheregionof0‐25and25‐50cm,because ithadbothhydrophilicand hydrophobic features, so it can dissolve in water andadsorbonsoilatthesametime.

InCaffeineoneandfifteenyearscolumns(Figure4and5),especiallyintheregionof150‐175and175‐200cm,indicatedahigher mobility of caffeine than ibuprofen and amoxicillin insoil. Ontheotherhand,caffeinehashighersolubilityinwaterthanothersdo[23].3.4.Massbalance

The purpose from this process is accounting forpharmaceuticalsenteringandleavingasystem,mathematicallythemassbalanceforasystemwithoutachemicalreactionisasfollows:

Input=Output+Accumulation (1)Inourstudywehavethefollowingequation:Input=Output(conc.inleachate)+(conc.adsorbedonsoil)+(Decomposedmaterials) (2)

Theinputofeachdrugperdaywas50mg/L,andthetotalinputforeachdrugin43dayswas2150mg/L.Table3showsthemassbalanceforthepharmaceuticalsdrugsthatweusedinourstudy.

Figure 5. Amoxicillin, ibuprofen, and caffeine concentrations measured insoillayersfor15years.

For amoxicillin its outputwas not of equal input becauseit’saverydegradablecompoundandaffectswithbiologicalandnon‐biological factors in soil and wastewater especiallyammonia,phosphateandhydroxylgroups.Allofthesefactorscanparticipateinthereductionofamoxicillinlevel.Againinthecase of ibuprofen it decomposed thermally producing manytoxic products like 4‐isobutlacetophenonewhich is a popularnon‐prescriptiondrugthatmayentailprolongeduse. It’susedto monitor the presence of all degradation products and tostudytheirlongtermtoxicity[24].

Forcaffeine, itdegradeswithina fewweeksandproducestheo‐bromineandtheo‐phyllinecompoundswhichareusefulintheindustrialworld[25‐26].

TheresultsinTable3mightbeexplainedintwoways:Firstthe life time of those pharmaceuticals are less than 5 hours.Secondly, whatever we got without degradation has beendiluted due to daily addition of amoxicillin, ibuprofen and

484 Jodehetal./EuropeanJournalofChemistry3(4)(2012)480‐484caffeine,inadditiontothebacterialeffectandthat’swhywegotverysmallconcentrations,lessthan1mg/L[27].4.Conclusion

The adsorption characteristics of pharmaceuticals in soilsand ground water are of great importance environmentally,because such processes are associated with the ecotoxicity,degradation, transportation, and bioaccumulation in the soilenvironment.Adsorptionofibuprofen,amoxicillin,andcaffeinewasstudiedusingsoilcolumnsandthefollowingresultswereobtained.

Theleachateandequilibriumofibuprofen,amoxicillinandcaffeine were best described using first‐order reaction andFreundlichisotherm.Ibuprofenconcentrationwasdecreasedinleachates amongst the one year and 15‐years columns. Thiswas due to the soil passage acting as an effective barrier foribuprofen,duetosorptionand/orduetomicrobialdegradationandthiswillaffectitsmobility.

Amoxicillin concentrations decreased dramatically andrapidly inleachateamongtheoneyearand15‐yearscolumns,more than ibuprofen due to its nature as a high degradablecompound.

Another observationwas observed. The concentrations ofcaffeine were obviously larger than that in ibuprofen andamoxicillinamongsttheoneyearand15‐yearscolumns;thisisbecause of that caffeine ismorewater soluble; despite it notreaching1mg/L.Duringthecolumns’studytheleachatefromthosecolumnswasfoundtobelessthan1.0mg/Lwhichmeansthat there will be no environmental effects of thosepharmaceuticals on the groundwater nor are further studiesrequired.Acknowledgement

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