Temporal evolution of emerging contaminants, priority substances and heavy metals most frequently detected in reclaimed water and grounwater in a volcanic aquifer

CEST2013 – A hens, G eece Re no: 0624 Please do no use page numbe s TEMPORAL EVOLUTION OF EMERGING CONTAMINANTS, PRIORITY SUBSTANCES AND HEAVY METALS MOST FREQUENTLY DETECTED IN RECLAIMED WATER AND GROUNDWATER IN A VOLCANIC AQUIFER E. ESTÉVEZ1, M.C. CABRERA1, J.R. FERNÁNDEZ-VERA2, A. MOLINA-DÍAZ3, J.R. ROBLES-MOLINA3 and M.P. PALACIOS-DÍAZ4 1 Uni e si y o Las Palmas de G an Cana ia, Depa men o Physics, 2 Labo a o io Ag oalimen a io y Fi opa ológico (Cabildo de G an Cana ia) 3 Uni e si y o Jaén, Analy ical Chemis y Resea ch G oup, Depa men o Physical and Analy ical Chemis y,4 Uni e si y o Las Palmas de G an Cana ia, Depa men o Animal Pa hology, 35017, Cana y Islands, Spain, [email p o ec ed], EXTENDED ABSTRACT The p esence o eme ging con aminan s has been p e iously desc ibed in eclaimed wa e and g oundwa e o G an Cana ia (Spain). Despi e o he en i onmen al isk associa ed o i iga ion wi h eclaimed wa e (R), his p ac ice is necessa y conside ing sus ainabili y o he hyd ological cycle in semia id zones, especially ega ding ag icul u al ac i i y. The aim o his s udy was: i) o analyse he e olu ion du ing wo yea s o con aminan s o eme ging conce n, p io i y subs ances (2008/105/EC) and hea y me als in eclaimed wa e (R) and in a olcanic aqui e in he NE o G an Cana ia whe e a gol cou se has been i iga ed wi h R since 1976 and ii) o ela e his p esence wi h physicochemical wa e p ope ies and hyd ogeological media. Reclaimed wa e and g oundwa e (GW) we e moni o ing qua e ly om July 2009 o Sep embe 2011. So p ion and deg ada ion p ocesses in soil accoun o mo e compounds being de ec ed in R. Diazinon and chlo en inphos we e de ec ed always in R and e bu hylazine, e bu yn and diu on a 90% o equency. Conside ing all he samples, he mos equen compounds we e chlo py i os e hyl, luo ene, phenan h ene and py ene. Al hough hei concen a ions we e equen ly below 50 ngL-1, some con aminan s, we e occasionally de ec ed a highe concen a ions. Chlo py i os e hyl and diu on a e p io i y subs ances de ec ed equen ly and a high concen a ions so hey mus be included in moni o ing s udies. Geology and loca ion seem o be ela ed o he eme ging compounds p esence due o occasional con amina ion e en s (no ela ed o R i iga ion) and he e o e no o an exis ence o a dange ous di use con amina ion le el. Thus, i is p e e able o selec wells wi h less s able chemical wa e quali y, in o de o moni o he isk o eme ging compounds p esence. Conside ing he ela ionship be ween con aminan p esence, chemical wa e quali y, seasonal a ia ion, hyd ogeological cha ac e is ics and wells loca ion we can conclude ha chlo py i os e hyl and diu on we e he mos dange ous p io i y subs ances in e ms o GW quali y so hey mus be included in all o he moni o ing s udies, a leas in Cana y Islands. Keywo ds: eme ging con aminan s, p io i y subs ances, hea y me als, eclaimed wa e , g oundwa e , i iga ion, olcanic zone. 1. INTRODUCTION Reclaimed wa e euse o e s a gua an eed supply and con ibu es o mi iga e he sho age o na u al wa e esou ces, especially, in semia id zones, whe e eclaimed wa e cons i u es an impo an sou ce o i iga ion wa e (Kuma e al., 2005; Kinney e al., 2006). In G an Cana ia (Spain), his p ac ice has been used o mo e han hi y yea s (Ma e o and Palacios, 1996), and eclaimed wa e cu en ly ep esen s 8% o wa e esou ces (Palacios e al., 2008). Nowadays, ad ances in ea men p ocesses esul in accep able eclaimed wa e quali ies. In he s udy a ea, e luen quali y has been imp o ed due o he ins alla ion o new in as uc u es, highligh ing a desalina ion sys em o he seconda y e luen since 2002. Aqui e s in eg a e echa ge wa e (na u al o om i iga ion e u ns) om di e en imes, especially in semia id zones and i g oundwa e able head is deep. The main sou ces o eme ging o ganic compounds in g oundwa e a e ela ed o was ewa e e luen s o euse, sep ic anks, li es ock ac i i ies and hospi al e luen s (Lapwo h e al., 2012). The main p ocesses con olling eme ging con aminan s du ing mig a ion h ough he soil, unsa u a ed zone and aqui e a e so p ion mainly o o ganic ma e and clay mine als, ion exchange, and mic obial deg ada ion o ans o ma ions. Indeed, he con aminan p ope ies as well as ansi ime h ough he unsa u a ed zone and g oundwa e esidence ime, edox condi ions and o al loading will be impo an in de e mining p esence and pe sis ence in g oundwa e . In olcanic ma e ials, he p esence o p e e en ial pa hs in he unsa u a ed zone can a ou a apid echa ge, so eme gen con aminan s can each he aqui e in ela i e sho imes. The p esence o eme ging con aminan s has been p e iously iden i ied and desc ibed in eclaimed wa e used o i iga e a gol cou se and in g oundwa e o he NE o G an Cana ia (Es é ez e al., 2012). This s udy moni o s 183 con aminan s o eme ging conce n and p io i y subs ances (2008/105/EC) since July 2009 o May 2010. The mos equen compounds we e ca eine, nico ine (s imulan s), chlo py i os e hyl (o ganophospha e insec icide), luo ene, phenan h ene and py ene (PAHs). Concen a ions we e always below 50 ngL-1, al hough some pha maceu icals and one pes icide, chlo py i os e hyl, we e occasionally de ec ed a highe concen a ions. This pape poin s o mo e en y ou es apa om eclaimed wa e i iga ion: ag icul u al p ac ices, sep ic anks leaks and sewe age b eaks, and men ions he impo ance o adso p ion, deg ada ion and p e e en ial lows phenomena. Howe e , empo al a ia ions o he con aminan s concen a ion had no been obse ed and a longe sampling pe iod was ecommended. One o he aims o ou s udy was o analyse he empo al e olu ion 36 con aminan s o he o al de ec ed by Es é ez e al. (2012), also including he esul s o an ex ended pe iod un il Sep embe 2011 and he esul s o 20 compounds non de ec ed in he i s s udy. A seconda y objec i e was o ela e hei p esence wi h chemical wa e p ope ies and hyd ogeological condi ions. Resul s o analyses o hea y me als in he whole pe iod a e also p esen ed. 2. MATERIAL AND METHODS 2.1. Loca ion and desc ip ion o he s udy a ea The Bandama Gol Cou se is loca ed in he NE o he G an Cana ia Island in he cen al pa o he Las Go e as basin, be ween 400 m and 500 m high. The Las Go e as basin is included in he N4 zone o he G an Cana ia Wa e Adminis a ion Plan (CIAGC, 1999), which is ep esen ed in Figu e 1. A e age p ecipi a ion in he a ea is 300 mm pe yea , he a e age annual empe a u e is 19°C, and he ange o humidi y is om 78% o 85%. Since 1976, he Bandama Gol Cou se has been i iga ed wi h eclaimed wa e om he Was ewa e T ea men Plan o Las Palmas de G an Cana ia, whe e e ia y ea men ins alled since 2002, consis ed in desalina ion and disin ec ion (Es e ez e al., 2010). Figu e 1. Loca ion and geology o he s udy a ea (modi ied om Balcells e al., 1990), si ua ion o he main a ines, he Bandama Calde a, he gol cou se and moni o ing poin s ( eclaimed wa e : R, wells: W0-W6 and he El Cula ón wa e galle y) and piezome y o Janua y 2009 (Cab e a e al., 2009, modi ied). The s udy a ea is nex o he qua e na y Bandama olcanic complex, and includes a olcanic calde a. F esh basal ic and basani ic la as and py oclas ic ma e ials (2,000 yea s old) ou c op in he a ea (Hansen and Mo eno, 2008). These ma e ials o e lie ac u ed basani ic la a lows and landslide b eccias, which co e Miocene phonoli es. In e bedded allu ial conglome a es ou c op inside he Bandama Calde a (Fig. 1). The island has a low pe meabili y “co e” wi h successi e co e s o younge , mo e pe meable ma e ials whe e g oundwa e low concen a es (Cus odio, 2003; SPA-15, 1975). P e ious hyd ogeological s udies in he a ea (Cab e a e al., 2009) ha e shown ha he g oundwa e lows om summi s o coas ollow a p e e en ial low line h ough he Las Go e as a ine and ha he e is a g oundwa e low om he gol cou se o he a ine. The g oundwa e able head is loca ed 250 m below he Bandama Gol Cou se. The aqui e sys em in he s udy a ea is exploi ed by sha wells o 2.5-3 m in diame e (“cana ian” wells) and 15-300 m dep hs. These i iga ing wells, desc ibed in Table 1, exploi mainly he ac u ed Miocene phonoli es wi h equi alen con inuous yields lowe han 1 Ls-1 pe day. Cab e a e al. (2010) demos a ed ha g oundwa e salini y inc eases om summi o sho e and ha hyd ogeochemis y changes om sodium bica bona e (occasionally wi h an endogenous gas supply) o chlo ide sodium bica bona e in he middle a ea and o sodium chlo ide on he coas al inge. Also, ni a e con en s inc ease om summi o sho e (up o 180 mgL-1), exceeding no ma i e h esholds (Di ec i e 91/676 EEC) so i is designed as a ulne able zone by he Regional Cana y Islands Go e nmen . The men ioned s udy concluded ha he wa e om he El Cula ón wa e galle y: G (Figu e 1 and Table 1), abou 40 m long and loca ed 60 m below he gol cou se, d ains a pe ched aqui e wi h a cons an low a e o 0.05 Ls-1 and ecei es wa e om di e en sou ces, including gol cou se leacha es. The wa e galle y hyd ogeochemis y di e s sligh ly om he g oundwa e sampled in he wells loca ed a he bo om o he Las Go e as a ine (Cab e a e al., 2009). Table 1. Desc ip ion o g oundwa e sampling s a ions (1: Dep h (m), 2: Bo om ele a ion (m), 3: Exploi ed Fo ma ion, 4: Hyd ochemical g oundwa e ype) and chemical pa ame e s o he moni o ing ne wo k poin s p esen ing mean (x) and s anda d de ia ion (sd). W0 W1 W2 W3 W4 W5 W6 G R x sd x sd x sd x sd x sd x sd x sd x sd x sd 1 208 133 32 158 34 70 96 40** 2 504 168 183 27 76 205 57 430 3 Roque Nublo Phonoli es Recen Basal s Recen Basal s - Phonoli es Phonoli es Phonoli es Recen Basal s - Phonoli es Roque Nublo Slipped b eccia 4 HCO3-Na Cl-HCO3- Na Cl-Na HCO3-Na Cl-Na Cl-SO4-Na Cl-Na Cl-Na pH 7.8b 0.3 7.6b 0.2 7.9b 0.3 6.6a 0.2 7.7b 0.2 8.0b 0.2 7.7b 0.0 7.7b 0.2 7.7b 0.2 EC 0.5a 0.0 1.6b 0.1 2.4c 0.1 3.0d 0.2 3.5e 0.2 1.6b 0.2 3.0d 0.1 1.7b 0.1 0.4a 0.1 NO3 - 7.2a 2.5 38.6b 4.3 117.0d 5.8 64.6c 18.3 185.0e 12.0 76.2c 13.5 133.0d 1.4 59.3c 7.9 8.1a 3.1 Na+ 50a 1.0 200bc 2.9 252cd 22.4 590 57.7 468e 33.5 183b 10.1 436e 24.7 304d 5.7 49a 28.2 K+ 10.3bc 0.5 13.1c 0.7 17.8d 1.3 37.8 4.4 41.9g 2.5 12.3c 1.0 33.0e 1.4 7.6ab 0.7 3.8a 1.8 Ca2+ 22.8b 0.5 51.9cd 5.0 99.3e 11.5 39.4c 6.8 107.7e 7.2 56.6d 8.0 62.0d 5.7 8.0a 0.4 11.6ab 1.6 Mg2+ 15.7ab 0.5 43.8c 5.2 76.5d 9.6 23.8b 4.5 88.6e 7.0 51.4c 7.1 76.0d 5.7 9.4a 0.6 8.7a 1.8 Cl- 31.3a 2.9 236.6b 7.0 412.0e 54.5 324.1c 18.6 676.5e 65.8 224.9b 17.0 624.0e 32.5 328.9c 10.3 58.4a 27.5 SO4 2- 7.9a 1.9 155.2b 9.6 232.1c 24.5 371.0d 45.7 335.5d 14.7 233.6c 29.5 251.5c 6.4 130.0b 4.1 17.2a 6.9 HCO3- 246bc 14 310cd 14 275cd 15 839e 127 346d 21 181ab 11 303cd 29 132a 12 93a 19 SiO2 89.5d 0.6 66.4c 1.3 40.2b 2.5 67.3c 4.4 48.8b 2.0 69.1c 5.0 72.0c 4.2 64.8c 4.2 28.3a 5.7 P 0.09a 0.0 0.09a 0.1 0.24bc 0.1 0.12ab 0.1 0.11ab 0.1 0.10a 0.1 0.25c 0.1 0.42d 0.0 0.13abc 0.1 B 0.06a 0.0 0.23ab 0.0 0.46ab 0.1 1.07b 0.1 0.83ab 0.1 0.18a 0.0 0.56ab 0.0 0.53ab 0.0 0.34ab 0.2 Fe 0.00a 0.0 0.00a 0.0 0.00a 0.0 0.00a 0.0 0.00a 0.0 0.01a 0.0 0.00a 0.0 0.00a 0.0 0.09b 0.1 Mn 0.01a 0.0 0.00a 0.0 0.03a 0.1 0.32b 0.1 0.01a 0.0 0.01a 0.0 0.00a 0.0 0.00a 0.0 0.02a 0.0 W ep esen s he 3 m-diame e wells, G: wa e galle y and R: eclaimed i iga ion wa e . Elec ic conduc i i y (EC). *: Da a wi h he same le e a e no signi ican ly di e en a 0.05. **: Leng h o he wa e galle y. Dep h om he gol cou se o he wa e galle y: 60m 2.2. Moni o ing ne wo k In he moni o ing ne wo k ca ied ou un il Sep embe 2011 we e sampled he gol cou se i iga ion wa e (R), he El Cula ón wa e galle y (G) and he same wells conside ed in Es é ez e al. (2012): W1, W2, W3 and W4, adding a con ol well loca ed a he highes al i ude and wo wells: W5 (nea e he gol cou se) - W6 (be ween W3 and W4). Samples we e aken in ambe glass bo les wi h Te lon caps (1L) o analyse o ganic compounds and in PE-LD bo les (250 ml and 500 ml) o analyse hea y me als and chemical pa ame e s espec i ely. All samples we e immedia ely s o ed in an insula ed con aine chilled wi h ice packs o be dispa ched by exp ess deli e y o he labo a o y. All he samples we e aken on he same da e and we e dispa ched wi hin 48h. I iga ion wa e was sampled di ec ly om a wa e ou le loca ed in a ai way o he gol cou se, wa e galle y samples we e aken om a pipe discha ging di ec ly om i , and well samples we e aken a e pumping a minimum o 15 minu es. This pape p esen s he esul s o he occu ence o 65 eme ging con aminan s and p io i y subs ances (2008/105/EC) in nine qua e ly campaigns conduc ed om July 2009 o Sep embe 2011. Only R and G we e sampled in all he da es. In he es o he moni o ing poin s he numbe o a ailable da a is: 4 (W0), 6 (W1), 8 (W2), 7 (W3 and W4), 3 (W5) and 2 (W6). 2.3. Me hods o analysis The analysis o o ganic compounds and hea y me als was conduc ed by he Labo a o y o Analy ical Chemis y a he Uni e si y o Jaén by using wo di e en analy ical me hods (Table 2). The sample p e- ea men applied o he isola ion and p e-concen a ion o non-pola and semi-pola ola ile compounds was a liquid-liquid ex ac ion (LLE) wi h n- hexane (Robles-Molina e al., 2010), ollowed by gas ch oma og aphy coupled wi h mass spec ome y analysis (GC-MS). The ins umen used was a CP-3800 gas ch oma og aph coupled wi h a 300-MS iple quad upole mass spec ome e (Va ian Inc. Walnu C eek, Cali o nia, USA). This me hodology was sa is ac o ily alida ed and ob ained good eco e y a es, as well as he RDS (%) o mos compounds. The me hods’ limi s o de ec ion, oge he wi h he es o alida ion pa ame e s o hose compounds ound in he samples we e p esen ed in Es é ez e al. (2012). Hea y me als we e de e mined by mass spec ome e wi h induc i ely coupled plasma (ICP-MS, Agilen Technologies 7500 Se ies) a e acuum il a ion o he samples. The es o he chemical pa ame e s we e de e mined in he Labo a o y o he Council o G an Cana ia (Labo a o io Ag oalimen a io y Fi opa ológico Labo a o io del Cabildo de G an Cana ia): pH and EC; ca ions, SiO2, P and B by ICP coupled by Op ical emission spec opho ome e (OES) and anions by ionic ch oma og aphy excep ca bona es and bica bona es (Po en iome ic De e mina ion). Table 2. Analy ical me hods employed in his wo k oge he wi h he de ec ed and non- de ec ed compounds which we e classi ied in o he ollowing g oups: pes icides, Polycyclic A oma ic Hyd oca bons (PAH), pha maceu icals and hea y me als. GC-MS me hod P e- ea men Ex ac ion me hod Analy ical Me hod  No il a ion  pH adjus men (3-4)  Liquid-Liquid Ex ac ion (LLE)  Sol en : n-Hexane  Gas Ch oma og aphy coupled o T iple Quad upole Mass Spec ome y (GC-TQMS). Ope a ion mode: MRM.  Column: Va ian Fac o Fou VF-5-ms (30m x 0.25mm i.d. x 0.25 µm) GC-MS: non de ec ed compounds GC-MS: de ec ed compounds Pes icides: alachlo , ame yn, ald in, a azine dese hyl, del ame h in, dield in, endosul an sulpha e, e hion, end in, hep achlo , isod in, ip odione, pa a hion, pa a hion me hyl, i lu alin, α-HCH, β-endosul an, β- HCH, δ-HCH. Pes icides: 4,4’-DDE, 4,4’-DDT, a azine, chlo en inphos, chlo o olu on, chlo py i os e hyl, diazinon, diu on, hexachlo obu adiene, hexachlo obenzene, isop o u on, me oxychlo , oxy luo en, pa a hion e hyl, pen achlo obenzene, p ocymidone, p opazine, simazine, e bu hylazine, e bu yn*, α -cype me h in, α-endosul an, γ-HCH. Pha maceu icals: ace aminophen, an ipy ine. PAH: acenaph ylene, an h acene, benzo(a)an h acene, benzo(a)py ene,benzo(b) luo an hene, benzo(g,h,i)pe ylene, benzo(k) luo an hene, ch ysene, dibenzo(a,h)an h acene, luo ene, indene(1,2,3-cd)py ene, phenan h ene, py ene. ICP-MS me hod P e- ea men Analy ical Me hod  Vacuum Fil a ion  Mass spec ome e wi h induc i ely coupled plasma. Babing on nebulize , sp ay chambe double e ige a ed (2 º C) o Pel ie qua z and Agilen I-AS au osample .  RF powe : 1500 W, plasma gas low o 15 Lmin-1; nebulize gas low: 1 Lm-1; auxilia y gas low: 0.9 min-1; suc ion eloci y o he sample: 0.25mLmin -1. ICP-MS: non de ec ed compounds ICP-MS: de ec ed compounds Hea y me als: Hg, Sn, P and Pd Hea y me als: Cd, Cu , Ni, Pb, Zn and Tl. P io i y subs ances (2008/105/EC) a e in cu si e. 3. RESULTS 3.1. Hyd ogeochemical cha ac e iza ion. Figu e 2 p esen s Schoelle -Be kalo and S i diag ams ob ained wi h he las analy ical esul s (Sep embe 2011). As i was desc ibed by Cab e a e al. (2010) GW quali y emains cons an o e ime, since simila diag ams had been depic ed. Figu e 2. Schoelle -Be kalo and S i diag ams o he g oundwa e moni o ing poin s ob ained o Sep embe 2011. As i was expec ed, W0 ep esen s sodium bica bona e low mine alized g oundwa e , simila han he wa e echa ge in his a ea. This g oundwa e coincides signi ican ly in e ms o mos o he chemical pa ame e s wi h R (Table 1), excep wi h highe con en s o K+, HCO3-, SiO2 and Fe, esul ing om he olcanic ocks hyd olysis. W3 wa e is sodium bica bona ed wi h signi ican ly la ge con en o Na+. I s low pH and high con en o HCO3- indica es ha g oundwa e is been en iching by endogenous CO2 gas con ibu ions. I coincides jus wi h he well ha exploi s he aqui e mo e deeply. The wa e pumped om W4 is signi ican ly di e en om he es o he wells in many o he chemical pa ame e s (EC, NO3-, SO4-2, Cl-2, Na+, K+, Ca+2, Mg+2) excep o SiO2 (Table 1). W4 ep esen s g oundwa e nea he discha ge a ea ( he coas ), whe e g oundwa e quali y is he esul o he p og essi e mine aliza ion h ough he g oundwa e low di ec ion, he in luence o saline echa ge wa e due o a idi y in coas al a eas and an h opogenic ac i i ies. The chlo ided sodic wa e om he wa e galle y p esen s a de ici o Ca+2, Mg+2 and HCO3-, an excess o NO3- and he highes P con en de ec ed. This ac would be ela ed wi h p e e en ial low phenomena. Compa ing wi h R, G is mo e concen a ed and seems o ecei e also al e na i e wa e sou ces. 3.1. P io i y subs ances and Con aminan s o Eme ging Conce n Table 3 shows he equency, mean and maximum concen a ion o he moni o ing ne wo k esul s. In he p e ious s udy (Es é ez e al., 2012) he pes icides and PAH p esen ing a 100% o equency we e: chlo py i os e hyl, luo ene, phenan h ene and py ene. Howe e , once he pe iod o ime was ex ended and he moni o ing poin s we e inc eased, he equency o chlo py i os e hyl de ec ion dec eased o 80% (Table 3). The concen a ion o his p io i y subs ance (2008/105/CE) is in a ange o 10 ngL-1 (bellow he 30 ngL-1 AA-EQS), al hough 20% o samples we e o e his alue, exceeding in he 5% o he esul s he Eu opean h eshold limi in g oundwa e (100 ngL-1) (2006/118/CE). These exceeding alues we e always de ec ed in summe , al hough in summe 2010 i was only de ec ed in h ee samples and bellow 10 ngL-1 (Figu e 3). The widesp ead p esence o his chlo ina ed o ganophospha e insec icide, aca icide and nema icide is ela ed o i s b oad spec um and use in ag icul u al p ac ices, gol cou ses, ca le and u ban media. The con inued use o his pes icide poses a isk o a mwo ke s and hei amilies he e o e he EPA is seeking o end ag icul u al use o chlo py i os. Al hough i s soil pe sis ence may depend on he o mula ion, a e o applica ion, soil ype, clima e and o he condi ions (Robe s e al., 1999) chlo py i os is s able in soils wi h epo ed hal - li es anging be ween 7 and 120 days (Ch is ensen e al., 2009). As chlo py i os does no pa i ion easily om soil o wa e i s p esence in uno wa e is likely a esul o soil-bound om e oding soil, a he han om dissol ed chlo py i os (EPA, 1999). The high equency and concen a ion o his adso bable compound de ec ed in he Las Go e as aqui e a e consis en wi h he p e e en ial low anspo desc ibed in olcanic aqui e s. In his sense, he highes alues ob ained in g oundwa e coincided wi h highe EC o ni a e con en s. Hence, i s p esence in high concen a ions seems o co espond o occasional con amina ion e en s (no ela ed o RW i iga ion) and no o an exis ence o a dange ous di use con amina ion le el. On Ap il 15, 2009, EPA included chlo py i os e hyl in he ini ial lis o chemicals o be sc eened o hei po en ial e ec s on he endoc ine sys em (EPA, 2009), which aims o co e all pes icide chemicals, as well as subs ances ha may occu in sou ces o d inking wa e o which a subs an ial popula ion may be exposed. Nowadays, EPA is e iewing es o de esponses and making a ailable he s a us o es o de esponses (EPA, 2013). As occu ed in ou p e ious s udy, luo ene, phenan h ene and py ene (PAH compounds) we e de ec ed wi h equencies o 100%. These compounds a e included in he lis o he 30 mos equen ly de ec ed compounds epo ed in he UK En i onmen al Agency G oundwa e Mic opollu an Da abase (S ua e al., 2012). The ange concen a ion o luo ene is less han 7 ngL-1. Phenan h ene and py ene (Figu e 4) concen a ion we e always below 25 ngL-1 in GW, excep o he anomalous maximum alues desc ibed in Es e ez e al., (2012) (close o 60 ngL-1). Non seasonal a ia ion was obse ed (Figu e 4) o hose PAHs. Table 3. Concen a ion (µgL-1: hea y me als, ngL-1: es o subs ances) and equency o de ec ion pe sample (i iga ion wa e : R, wa e galle y: G and wells: W0- W6), o hose compounds de ec ed a leas once in he whole pe iod (July 2009 – Sep embe 2011). Nº: Compound Numbe o de ed by g oup (pes icides: 1-23, PAH: 24-36, hea y me als: 37-42 and pha maceu icals: 43-44) and by equency o de ec ion, X: mean concen a ion, Max: maximum concen a ion, n : o al numbe o analysis, nd: numbe o de ec ions, %T: o al equency (GW and R), %R: eclaimed wa e equency and %GW: g oundwa e equency. R G W0 W1 W2 W3 W4 W5 W6 Nº X Max X Max X Max X Max X Max X Max X Max X Max X Max F equency n = 9 n = 9 n = 4 n = 6 n = 8 n = 7 n = 7 n = 3 n = 2 % T % R %GW 1 5.9 27.2 4.2 9.3 1.3 2.9 2.3 4.1 2.4 9.9 5.3 13.4 3.1 6.8 2.4 4.4 3.6 5.6 nd/n 6/9 6/9 4/4 5/6 8/8 6/7 6/7 3/3 2/2 83.3 66.7 86.7 2* 6.8 18.1 10 39 3.3 5.3 62 223 52 294 7.7 28.2 51 262 3 6.3 5.2 nd/n 6/9 7/9 3/4 5/6 6/8 7/7 6/7 3/3 1/2 79.6 66.7 82.2 3* 9.8 42.3 2.8 4.6 2.6 9.3 13.8 8 25 4.8 7.6 131 624 3 3.7 nd/n 8/9 5/9 1/4 4/6 5/8 4/7 5/7 2/3 61.1 88.9 55.6 4* 6.2 18 1.7 2.8 1 3.8 8.1 2.8 6.3 2 2.6 68 195 0.5 nd/n 8/9 3/9 1/4 5/6 6/8 4/7 3/7 1/3 55.6 88.9 48.9 5 1.8 3.2 2.7 7.6 1.6 2.4 4.5 11.7 2.3 3.4 2.4 7.3 1.3 1.5 0.9 1.6 3.2 nd/n 5/9 4/9 3/4 3/6 5/8 4/7 3/7 2/3 1/2 53.7 55.6 53.3 6 12 36.1 1.8 0.7 1.3 0.9 0.9 0.8 nd/n 9/9 1/9 2/6 4/8 3/7 2/7 38.9 100 26.7 7* 4.1 11.3 1.6 1 2.9 4 5.5 1.7 3.9 126 250 nd/n 8/9 1/9 1/4 2/6 1/8 3/7 2/7 33.3 88.9 22.2 8* 0.4 0.7 0.8 1.9 14 34.5 14 36 164 325 nd/n 1/9 2/9 1/4 3/6 3/8 2/7 22.2 11.1 24.4 9* x 35 191 101 nd/n 9/9 1/7 18.5 100 2.2 10* 1.3 2.5 9.1 13.8 4 6.7 2.8 4.3 242 484 nd/n 1/9 1/9 2/6 2/8 1/7 2/7 18.5 11.1 20 11* 2.2 0.2 2.5 4.4 2.8 1.6 2.3 109 217 nd/n 1/9 1/9 2/6 1/8 2/7 2/7 16.7 11.1 17.8 12 0.4 1.2 1.7 1.6 0.4 0.5 0.3 0.4 0.3 1.0 nd/n 1/9 2/9 1/6 2/8 2/7 1/7 1/3 14.8 11.1 15.6 13 0.8 1.3 2.1 2.8 2.8 6.4 11 nd/n 1/9 2/6 1/8 1/7 2/7 13 0 15.6 14 0.4 1.2 0.5 5.1 nd/n 1/9 1/9 1/4 1/6 9.3 11.1 8.9 15 8 14.7 1.5 1.8 nd/n 2/9 2/4 7.4 22.2 4.4 16 0.1 0.2 0.5 nd/n 1/9 1/7 1/2 5.6 0 6.7 17 6.5 9 8 42 nd/n 1/9 1/4 1/6 1/7 5.6 0 6.7 18 0.2 0.2 1.5 nd/n 1/9 1/6 1/8 5.6 0 6.7 19 3 3 nd/n 2/9 3.7 22.2 0 20 0.3 0.8 nd/n 1/6 1/8 3.7 0 4.4 21 20 nd/n 1/9 1.9 11.1 0 22 0.9 nd/n 1/8 1.9 0 2.2 23 12 nd/n 1/6 1.9 0 2.2 24 8.1 60 1.2 3.1 1 2.2 1.3 3.2 1.9 6.5 1.7 5.6 1.4 2.1 0.7 1.4 1.6 1.8 nd/n 9/9 9/9 4/4 6/6 8 7/7 7/7 3/3 2/2 100 100 100 25 6 18.7 5.7 18 6.4 14 13 57 6.9 18.9 5.8 9.8 2.7 5.8 9.4 13 nd/n 9/9 9/9 4/4 8/8 7/7 7/7 3/3 2/2 100 100 100 26 4.9 17.6 3.9 8.9 4.4 6.7 4.5 6.9 9.4 23 2.5 5 7.1 11 nd/n 9/9 9/9 4/4 6/6 7/7 3/3 2/2 100 100 100 27 1 1.6 0.5 0.6 0.4 0.5 0.4 0.7 0.5 0.8 0.4 0.5 0.4 nd/n 2/9 3/9 1/4 1/6 3/8 3/7 2/7 1/2 27.8 22.2 28.9 28 2.3 6.2 2.7 9.3 0.5 0.9 1.2 4.8 12 11 21.4 8.5 17 nd/n 3/9 4/9 1/4 2/6 3/8 2/7 2/7 25.9 11.1 28.9 29 0.2 0.2 0.3 0.4 0.3 0.4 0.4 0.2 0.4 0.2 0.3 nd/n 5/9 2/9 1/6 2/8 3/7 2/7 24.1 33.3 22.2 30 0.3 0.3 0.3 0.4 0.3 0.4 0.4 0.8 0.5 0.7 0.2 0.2 nd/n 2/9 2/9 2/6 3/8 2/7 2/7 24.1 22.2 24.4 31 0.7 1.2 0.7 0.9 0.5 0.6 0.6 0.6 1.2 1.8 1.3 nd/n 3/9 2/9 2/6 2/8 2/7 1/7 22.2 33.3 20 32 0.3 0.4 0.5 0.8 1.2 1.4 0.4 0.6 0.4 nd/n 1/9 2/9 1/6 2/8 2/7 1/7 16.7 11.1 17.8 33 0.2 0.3 0.4 0.6 1.1 1.2 0.3 0.4 0.4 nd/n 1/9 2/9 1/6 2/8 2/7 1/7 16.7 11.1 17.8 34 0.8 0.9 0.3 0.4 0.3 0.4 0.3 0.4 nd/n 2/9 2/9 2/6 2/7 14.8 22.2 13.3 35* 7.7 14 0.5 105 0.5 nd/n 1/9 1/9 1/8 1/7 1/3 9.3 11.1 8.9 36 0.3 18 0.5 nd/n 1/9 1/4 1/8 5.6 11.1 4.4 37* 425 811 351 1022 280 396 381 1006 292 532 362 563 377 610 216 353 282 317 nd/n 9/9 9/9 3/4 6/6 7/8 7/7 7/7 3/3 2/2 98.1 100 97.8 38* x 347 1732 5.6 24 2.2 3.7 29 140 8.6 34 3.8 6.9 5.4 18 1.2 2 4,3 4,7 nd/n 9/9 8/9 3/4 6/6 6/8 7/7 6/7 2/3 2/2 81.5 100 77.8 39 10 24.7 4.4 15 4.5 5.6 4.9 12.6 15 35.3 10 19 2.5 3,3 6,9 11 nd/n 7/9 9/9 2/4 6/6 7/7 7/7 3/3 2/2 81.5 77.8 82.2 40 0.2 0.4 0.2 0.4 0.2 0.5 0.2 0.3 0.2 0.4 0.1 nd/n 4/9 4/9 4/6 4/8 3/7 1/3 37 44.4 35.6 41 0.3 0.6 0 0.1 0.1 0.1 0.7 0.4 2.7 nd/n 3/9 5/9 1/4 1/6 5/7 1/7 1/3 16.7 33.3 13.3 42 0.05 0.007 0.007 1.1 0.9 0.007 nd/n 1/9 1/9 1/8 1/7 1/3 2/2 13 11.1 13.3 43 51 92 nd/n 5/9 9.3 55.6 0 44 x 1832 35 nd/n 1/9 1/4 3.7 11.1 2.2 *: Compounds e ec ed a leas once in he g oundwa e (G o W0 - W6) a a concen ac ion highe han 0.1 µgL-1. x: de ec ed a leas once in he eclaimed wa e (R) a a concen a ion highe han 0.1 µgL-1. Nº = Compound Numbe o de ed by g oup (Pes icides: 1- 23, PAH: , Pha maceu icals: and hea y me als: ) and equency o de ec ion. PESTICIDES: 1: hexachlo obenzene, 2*: chlo py i os e hyl, 3*: e bu hylazine, 4*: diu on, 5: oxy luo en, 6: chlo en inphos, 7*: e bu yn, 8*: p ocymidone, 9* x: diazinon, 10*: a azine, 11*: p opazine, 12: pen achlo obenzene, 13: simazine,14:chlo o olu on, 15: γ-HCH, 16: 4,4’-DDT, 17: α-endosul an, 18: 4,4’-DDE, 19: isop o u on, 20: hexachlo obu adiene, 21: α-cype me h in, 22: me oxychlo , 23: pa a hion e hyl. PAH: 24: luo ene, 25: phenan h ene, 26: py ene, 27:acenaph ylene, 28: ch ysene, 29: benzo(b) luo an hene, 30:benzo(a)an h acene, 31: benzo(ghi)pe ylene, 32: indene(1,2,3-cd)py ene, 33: dibenzo(a,h)an h acene, 34: benzo(k) luo an hene, 35*: an h acene, 36: benzo(a)py ene. HEAVY METALS: 37*: Zn, 38 x: Cu, 39: Ni, 40: Cd, 41: Pb and 42: Tl. PHARMACEUTICALS: 43: an ipy ine, 44 x: ace aminophen.